WorldWideScience

Sample records for antioxidant iron chelating

  1. Flavonoids function as antioxidants: By scavenging reactive oxygen species or by chelating iron?

    Science.gov (United States)

    Wuguo, Deng; Xingwang, Fang; Jilan, Wu

    1997-09-01

    Flavonoids have been reported to exhibit strong antioxidative activity. In the present work, a systematic mechanistic study has been performed on five flavonoids (baicalin, hesperidin, naringin, quercetin and rutin) selected according to their structural characteristics. The experimental results reveal that flavonoids function as antioxidant mainly by chelating iron ions and by scavenging peroxyl radicals whereas their OH radical scavenging effect is much less important.

  2. Flavonoids function as antioxidants: by scavenging reactive oxygen species or by chelating iron?

    International Nuclear Information System (INIS)

    Flavonoids have been reported to exhibit strong antioxidative activity. In the present work, a systematic mechanistic study has been performed on five flavonoids (baicalin, hesperidin, naringin, quercetin and rutin) selected according to their structural characteristics. The experimental results reveal that flavonoids function as antioxidant mainly by chelating iron ions and by scavenging peroxyl radicals whereas their OH radical scavenging effect is much less important. (author)

  3. Flavonoids function as antioxidants: by scavenging reactive oxygen species or by chelating iron?

    Energy Technology Data Exchange (ETDEWEB)

    Wuguo Deng; Xingwang Fang; Jilan Wu [Peking Univ., Technical Physics Dept., Beijing (China)

    1997-09-01

    Flavonoids have been reported to exhibit strong antioxidative activity. In the present work, a systematic mechanistic study has been performed on five flavonoids (baicalin, hesperidin, naringin, quercetin and rutin) selected according to their structural characteristics. The experimental results reveal that flavonoids function as antioxidant mainly by chelating iron ions and by scavenging peroxyl radicals whereas their OH radical scavenging effect is much less important. (author).

  4. Combined Iron Chelator and Antioxidant Exerted Greater Efficacy on Cardioprotection Than Monotherapy in Iron-Overloaded Rats

    Science.gov (United States)

    Wongjaikam, Suwakon; Kumfu, Sirinart; Khamseekaew, Juthamas; Sripetchwandee, Jirapas; Srichairatanakool, Somdet; Fucharoen, Suthat; Chattipakorn, Siriporn C.; Chattipakorn, Nipon

    2016-01-01

    Background Iron chelators are used to treat iron overload cardiomyopathy patients. However, a direct comparison of the benefits of three common iron chelators (deferoxamine (DFO), deferiprone (DFP) and deferasirox (DFX)) or an antioxidant (N-acetyl cysteine (NAC)) with a combined DFP and NAC treatments on left ventricular (LV) function with iron overload has not been investigated. Methods and Findings Male Wistar rats were fed with either a normal diet or a high iron diet (HFe group) for 4 months. After 2 months, the HFe-fed rats were divided into 6 groups to receive either: a vehicle, DFO (25 mg/kg/day), DFP (75 mg/kg/day), DFX (20 mg/kg/day), NAC (100 mg/kg/day) or the combined DFP and NAC for 2 months. Our results demonstrated that HFe rats had increased plasma non-transferrin bound iron (NTBI), malondialdehyde (MDA), cardiac iron and MDA levels and cardiac mitochondrial dysfunction, leading to LV dysfunction. Although DFO, DFP, DFX or NAC improved these parameters, leading to improved LV function, the combined DFP and NAC therapy caused greater improvement, leading to more extensively improved LV function. Conclusions The combined DFP and NAC treatment had greater efficacy than monotherapy in cardioprotection through the reduction of cardiac iron deposition and improved cardiac mitochondrial function in iron-overloaded rats. PMID:27428732

  5. Aroylhydrazone iron chelators: Tuning antioxidant and antiproliferative properties by hydrazide modifications.

    Science.gov (United States)

    Hrušková, Kateřina; Potůčková, Eliška; Hergeselová, Tereza; Liptáková, Lucie; Hašková, Pavlína; Mingas, Panagiotis; Kovaříková, Petra; Šimůnek, Tomáš; Vávrová, Kateřina

    2016-09-14

    Aroylhydrazones such as salicylaldehyde isonicotinoyl hydrazone (SIH) are tridentate iron chelators that may possess antioxidant and/or antineoplastic activities. Their main drawback, their low stability in plasma, has recently been partially overcome by exchanging the aldimine hydrogen for an unbranched alkyl group. In this study, ten analogs of methyl- and ethyl-substituted SIH derivatives with modified hydrazide scaffolds were synthesized to further explore their structure-activity relationships. Their iron-chelation efficiencies, anti- or pro-oxidant potentials, abilities to induce protection against model oxidative injury on the H9c2 cell line derived from rat embryonic cardiac tissue, cytotoxicities on the same H9c2 cells and antiproliferative activities on MCF-7 human breast adenocarcinoma and HL-60 human promyelotic leukemia cell lines were evaluated. Compounds derived from lipophilic naphthyl and biphenyl hydrazides displayed highly selective antiproliferative activities against both MCF-7 and HL-60 cell lines, and they showed markedly improved stabilities in plasma compared to SIH. Of particular interest is a hydrazone prepared from 2-hydroxypropiophenone and pyridazin-4-carbohydrazide that showed a considerable antiproliferative effect and protected cardiomyoblasts against oxidative stress with a five-fold higher selectivity compared to the parent compound SIH. Thus, this work highlighted new structure-activity relationships among antiproliferative and antioxidant aroylhydrazones and identified new lead compounds for further development. PMID:27187862

  6. Iron Chelators and Antioxidants Regenerate Neuritic Tree and Nigrostriatal Fibers of MPP+/MPTP-Lesioned Dopaminergic Neurons.

    Directory of Open Access Journals (Sweden)

    Pabla Aguirre

    Full Text Available Neuronal death in Parkinson's disease (PD is often preceded by axodendritic tree retraction and loss of neuronal functionality. The presence of non-functional but live neurons opens therapeutic possibilities to recover functionality before clinical symptoms develop. Considering that iron accumulation and oxidative damage are conditions commonly found in PD, we tested the possible neuritogenic effects of iron chelators and antioxidant agents. We used three commercial chelators: DFO, deferiprone and 2.2'-dypyridyl, and three 8-hydroxyquinoline-based iron chelators: M30, 7MH and 7DH, and we evaluated their effects in vitro using a mesencephalic cell culture treated with the Parkinsonian toxin MPP+ and in vivo using the MPTP mouse model. All chelators tested promoted the emergence of new tyrosine hydroxylase (TH-positive processes, increased axodendritic tree length and protected cells against lipoperoxidation. Chelator treatment resulted in the generation of processes containing the presynaptic marker synaptophysin. The antioxidants N-acetylcysteine and dymetylthiourea also enhanced axodendritic tree recovery in vitro, an indication that reducing oxidative tone fosters neuritogenesis in MPP+-damaged neurons. Oral administration to mice of the M30 chelator for 14 days after MPTP treatment resulted in increased TH- and GIRK2-positive nigra cells and nigrostriatal fibers. Our results support a role for oral iron chelators as good candidates for the early treatment of PD, at stages of the disease where there is axodendritic tree retraction without neuronal death.

  7. Ferritin iron minerals are chelator targets, antioxidants, and coated, dietary iron

    OpenAIRE

    Theil, Elizabeth C.

    2010-01-01

    Cellular ferritin is central for iron balance during transfusions therapies; serum ferritin is a small fraction of body ferritin, albeit a convenient reporter. Iron overload induces extra ferritin protein synthesis but the protein is overfilled with the extra iron that damages ferritin, with conversion to toxic hemosiderin. Three new approaches that manipulate ferritin to address excess iron, hemosiderin, and associated oxidative damage in Cooley’s Anemia and other iron overload conditions, a...

  8. Structure-activity relationships of novel salicylaldehyde isonicotinoyl hydrazone (SIH analogs: iron chelation, anti-oxidant and cytotoxic properties.

    Directory of Open Access Journals (Sweden)

    Eliška Potůčková

    Full Text Available Salicylaldehyde isonicotinoyl hydrazone (SIH is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability. Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O, which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.

  9. Synthesis, antioxidant activities of the nickel(II), iron(III) and oxovanadium(IV) complexes with N2O2 chelating thiosemicarbazones

    Science.gov (United States)

    Bal-Demirci, Tülay; Şahin, Musa; Özyürek, Mustafa; Kondakçı, Esin; Ülküseven, Bahri

    The nickel(II), iron(III) and oxovanadium(IV) complexes of the N2O2 chelating thiosemicarbazones were synthesized using 4-hydroxysalicyladehyde-S-methylthiosemicarbazone and R1-substitute-salicylaldehyde (R1: 4-OH, H) in the presence of Ni(II), Fe(III), VO(IV) ions by the template reaction. The structures of the thiosemicarbazone complexes were characterized by FT-IR, 1H NMR, elemental, ESI-MS and APCI-MS analysis. The synthesized compounds were screened for their antioxidant capacity by using the cupric reducing antioxidant capacity (CUPRAC) method. Trolox equivalent antioxidant capacity (TEAC) of iron(III) complex, 1c, was measured to be higher than that of the other complexes. Other parameters of antioxidant activity (scavenging effects on rad OH, O2rad - and H2O2) of these compounds were also determined. All the compounds have shown encouraging ROS scavenging activities.

  10. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    OpenAIRE

    Ana Paula Oliveira Amorim; Márcia Cristina Campos de Oliveira; Thiago de Azevedo Amorim; Aurea Echevarria

    2013-01-01

    The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE) and the hydromethanolic fraction (Fraction 1), resulting in a concentration of 0.5853 g/1...

  11. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    Directory of Open Access Journals (Sweden)

    Ana Paula Oliveira Amorim

    2013-07-01

    Full Text Available The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE and the hydromethanolic fraction (Fraction 1, resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract.The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE and 6.6 μg·mL−1 (Fraction 1. The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform.

  12. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem.

    Science.gov (United States)

    Oliveira Amorim, Ana Paula; Campos de Oliveira, Márcia Cristina; de Azevedo Amorim, Thiago; Echevarria, Aurea

    2013-01-01

    The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE) and the hydromethanolic fraction (Fraction 1), resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract).The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL(-1) (CE) and 6.6 μg·mL(-1) (Fraction 1). The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform. PMID:26784338

  13. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    Science.gov (United States)

    Oliveira Amorim, Ana Paula; Campos de Oliveira, Márcia Cristina; de Azevedo Amorim, Thiago; Echevarria, Aurea

    2013-01-01

    The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE) and the hydromethanolic fraction (Fraction 1), resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract).The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE) and 6.6 μg·mL−1 (Fraction 1). The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform. PMID:26784338

  14. Combination therapies in iron chelation

    Directory of Open Access Journals (Sweden)

    Raffaella Origa

    2014-12-01

    Full Text Available The availability of oral iron chelators and new non-invasive methods for early detection and treatment of iron overload, have significantly improved the life expectancy and quality of life of patients with b thalassemia major. However, monotherapy is not effective in all patients for a variety of reasons. We analyzed the most relevant reports recently published on alternating or combined chelation therapies in thalassemia major with special attention to safety aspects and to their effects in terms of reduction of iron overload in different organs, improvement of complications, and survival. When adverse effects, such as gastrointestinal upset with deferasirox or infusional site reactions with deferoxamine are not tolerable and organ iron is in an acceptable range, alternating use of two chelators (drugs taken sequentially on different days, but not taken on the same day together may be a winning choice. The association deferiprone and deferoxamine should be the first choice in case of heart failure and when dangerously high levels of cardiac iron exist. Further research regarding the safety and efficacy of the most appealing combination treatment, deferiprone and deferasirox, is needed before recommendations for routine clinical practice can be made.

  15. Iron mobilization using chelation and phlebotomy

    DEFF Research Database (Denmark)

    Flaten, T. P.; Aaseth, J.; Andersen, Ole;

    2012-01-01

    are phlebotomy and chelation. Phlebotomy is the initial treatment of choice in haemochromatosis, while chelation is a mainstay in the treatment of transfusional siderosis. The classical iron chelator is deferoxamine (Desferal), but due to poor gastrointestinal absorption it has to be administered intravenously...... or subcutaneously, mostly on a daily basis. Thus, there is an obvious need to find and develop new effective iron chelators for oral use. In later years, particularly two such oral iron chelators have shown promise and have been approved for clinical use, namely deferiprone (Ferriprox) and deferasirox (Exjade...

  16. Antioxidant properties of modified rutin esters by DPPH, reducing power, iron chelation and human low density lipoprotein assays

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Nielsen, Nina Skall; Jacobsen, Charlotte;

    2010-01-01

    rutin compounds exhibited decreased reducing power and metal chelating abilities as compared to rutin. Conversely, investigations on the oxidation of human low density lipoprotein (LDL) revealed that rutin laurate was most effective in inhibiting oxidation by prolonging LDL lag time for an in vitro...

  17. Acute iron poisoning. Rescue with macromolecular chelators.

    OpenAIRE

    Mahoney, J R; Hallaway, P E; Hedlund, B E; Eaton, J. W.

    1989-01-01

    Acute iron intoxication is a frequent, sometimes life-threatening, form of poisoning. Present therapy, in severe cases, includes oral and intravenous administration of the potent iron chelator, deferoxamine. Unfortunately, high dose intravenous deferoxamine causes acute hypotension additive with that engendered by the iron poisoning itself. To obviate this problem, we have covalently attached deferoxamine to high molecular weight carbohydrates such as dextran and hydroxyethyl starch. These ma...

  18. Trypanotoxic activity of thiosemicarbazone iron chelators.

    Science.gov (United States)

    Ellis, Samuel; Sexton, Darren W; Steverding, Dietmar

    2015-03-01

    Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of Trypanosoma brucei and human leukaemia HL-60 cells. In addition to their iron chelating properties, TSC24 and Dp44mT inhibit topoisomerase IIα while 3-AP inactivates ribonucleotide reductase. All three compounds exhibited anti-trypanosomal activity, with minimum inhibitory concentration (MIC) values ranging between 1 and 100 µM and 50% growth inhibition (GI50) values of around 250 nM. Although the compounds did not kill HL-60 cells (MIC values >100 µM), TSC24 and Dp44mT displayed considerable cytotoxicity based on their GI50 values. Iron supplementation partly reversed the trypanotoxic and cytotoxic activity of TSC24 and Dp44mT but not of 3-AP. This finding suggests possible synergy between the iron chelating and topoisomerase IIα inhibiting activity of the compounds. However, further investigation using separate agents, the iron chelator deferoxamine and the topoisomerase II inhibitor epirubicin, did not support any synergy for the interaction of iron chelation and topoisomerase II inhibition. Furthermore, TSC24 was shown to induce DNA degradation in bloodstream forms of T. brucei indicating that the mechanism of trypanotoxic activity of the compound is topoisomerase II independent. In conclusion, the data support further investigation of thiosemicarbazone iron chelators with dual activity as lead compounds for anti-trypanosomal drug development. PMID:25595343

  19. IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

    Directory of Open Access Journals (Sweden)

    Paolo Cianciulli

    2009-06-01

    Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

  20. Study on antioxidant activity of lipids with iron threonine chelate%苏氨酸铁螯合物对油脂的抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    陶浚; 胡晓波; 孙文捷; 聂少平; 谢明勇

    2012-01-01

    摘要:采用Schaal烘箱法研究了氯化亚铁、苏氨酸铁螯合物、TBHQCL不同浓度苏氨酸铁螯合物对动植物油脂的抗氧化作用。实验结果表明,苏氨酸铁螯合物在添加剂量为0.5g/kg水平以上,对油脂具有催化自动氧化酸败的作用;但在油脂中添加剂量为0.1g/kg时能有效的降低油脂的过氧化值,表现出一定的抗氧化能力。%This experiment was studied the antioxidant activity of lipids with ferrous chloride,iron threonine chelate,TBHQ and the different concentration of iron threonine chelate by the method of Schaal oven. The results indicated that it could catalyze oxidation of chelate was more than 0.5g/kg. However,it could pids to rancidity when the dosage of the iron threonine effectively reduce the peroxide value at the dosage of 0.1 g/kg.

  1. New developments and controversies in iron metabolism and iron chelation therapy

    Science.gov (United States)

    Kontoghiorghe, Christina N; Kontoghiorghes, George J

    2016-01-01

    Iron is essential for all organisms including microbial, cancer and human cells. More than a quarter of the human population is affected by abnormalities of iron metabolism, mainly from iron deficiency and iron overload. Iron also plays an important role in free radical pathology and oxidative damage which is observed in almost all major diseases, cancer and ageing. New developments include the complete treatment of iron overload and reduction of morbidity and mortality in thalassaemia using deferiprone and selected deferiprone/deferoxamine combinations and also the use of the maltol iron complex in the treatment of iron deficiency anaemia. There is also a prospect of using deferiprone as a universal antioxidant in non iron overloaded diseases such as neurodegenerative, cardiovascular, renal, infectious diseases and cancer. New regulatory molecules of iron metabolism such as endogenous and dietary chelating molecules, hepcidin, mitochondrial ferritin and their role in health and disease is under evaluation. Similarly, new mechanisms of iron deposition, removal, distribution and toxicity have been identified using new techniques such as magnetic resonance imaging increasing our understanding of iron metabolic processes and the targeted treatment of related diseases. The uniform distribution of iron in iron overload between organs and within each organ is no longer valid. Several other controversies such as the toxicity impact of non transferrin bound iron vs injected iron, the excess levels of iron in tissues causing toxicity and the role of chelation on iron absorption need further investigation. Commercial interests of pharmaceutical companies and connections to leading journals are playing a crucial role in shaping worldwide medical opinion on drug sales and use but also patients’ therapeutic outcome and safety. Major controversies include the selection criteria and risk/benefit assessment in the use of deferasirox in thalassaemia and more so in idiopathic

  2. New developments and controversies in iron metabolism and iron chelation therapy.

    Science.gov (United States)

    Kontoghiorghe, Christina N; Kontoghiorghes, George J

    2016-03-26

    Iron is essential for all organisms including microbial, cancer and human cells. More than a quarter of the human population is affected by abnormalities of iron metabolism, mainly from iron deficiency and iron overload. Iron also plays an important role in free radical pathology and oxidative damage which is observed in almost all major diseases, cancer and ageing. New developments include the complete treatment of iron overload and reduction of morbidity and mortality in thalassaemia using deferiprone and selected deferiprone/deferoxamine combinations and also the use of the maltol iron complex in the treatment of iron deficiency anaemia. There is also a prospect of using deferiprone as a universal antioxidant in non iron overloaded diseases such as neurodegenerative, cardiovascular, renal, infectious diseases and cancer. New regulatory molecules of iron metabolism such as endogenous and dietary chelating molecules, hepcidin, mitochondrial ferritin and their role in health and disease is under evaluation. Similarly, new mechanisms of iron deposition, removal, distribution and toxicity have been identified using new techniques such as magnetic resonance imaging increasing our understanding of iron metabolic processes and the targeted treatment of related diseases. The uniform distribution of iron in iron overload between organs and within each organ is no longer valid. Several other controversies such as the toxicity impact of non transferrin bound iron vs injected iron, the excess levels of iron in tissues causing toxicity and the role of chelation on iron absorption need further investigation. Commercial interests of pharmaceutical companies and connections to leading journals are playing a crucial role in shaping worldwide medical opinion on drug sales and use but also patients' therapeutic outcome and safety. Major controversies include the selection criteria and risk/benefit assessment in the use of deferasirox in thalassaemia and more so in idiopathic

  3. Trypanotoxic activity of thiosemicarbazone iron chelators

    OpenAIRE

    Ellis, Samuel; Sexton, Darren; Steverding, Dietmar

    2015-01-01

    Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of T. brucei and human leukaemia HL-60 cells. In addition to t...

  4. Antioxidant, Free Radical Scavenging and Metal Chelating Characteristics of Propolis

    Directory of Open Access Journals (Sweden)

    Hikmet Geckil

    2005-01-01

    Full Text Available This study was undertaken to determine the reducing characteristics, metal chelating capability, anti-lipid peroxidative and antiradical properties of propolis compared to two widely used artificial antioxidants, Butylated Hydroxyanisole (BHA and Butylated Hydroxytoluene (BHT. The water and ethanol extracts of propolis showed significantly a different degree of metal chelating, radical scavenging activity and reducing power. In general, ethanol extracts of propolis showed higher activity regarding these parameters. Synthetic antioxidants showed better activities than both propolis extracts for antioxidant properties, utilizing a -carotene bleaching method. At higher concentrations, the reducing power of ethanol extract of propolis was similar to that of artificial antioxidants. The metal chelating activity of both water and ethanol extracts of propolis was comparable to that of EDTA and significantly higher than both BHA and BHT.

  5. Antioxidant, Free Radical Scavenging and Metal Chelating Characteristics of Propolis

    OpenAIRE

    Hikmet Geckil; Burhan Ates; Gokhan Durmaz; Selim Erdogan; Ismet Yilmaz

    2005-01-01

    This study was undertaken to determine the reducing characteristics, metal chelating capability, anti-lipid peroxidative and antiradical properties of propolis compared to two widely used artificial antioxidants, Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT). The water and ethanol extracts of propolis showed significantly a different degree of metal chelating, radical scavenging activity and reducing power. In general, ethanol extracts of propolis showed higher activity re...

  6. A novel antimycobacterial compound acts as an intracellular iron chelator.

    Science.gov (United States)

    Dragset, Marte S; Poce, Giovanna; Alfonso, Salvatore; Padilla-Benavides, Teresita; Ioerger, Thomas R; Kaneko, Takushi; Sacchettini, James C; Biava, Mariangela; Parish, Tanya; Argüello, José M; Steigedal, Magnus; Rubin, Eric J

    2015-04-01

    Efficient iron acquisition is crucial for the pathogenesis of Mycobacterium tuberculosis. Mycobacterial iron uptake and metabolism are therefore attractive targets for antitubercular drug development. Resistance mutations against a novel pyrazolopyrimidinone compound (PZP) that is active against M. tuberculosis have been identified within the gene cluster encoding the ESX-3 type VII secretion system. ESX-3 is required for mycobacterial iron acquisition through the mycobactin siderophore pathway, which could indicate that PZP restricts mycobacterial growth by targeting ESX-3 and thus iron uptake. Surprisingly, we show that ESX-3 is not the cellular target of the compound. We demonstrate that PZP indeed targets iron metabolism; however, we found that instead of inhibiting uptake of iron, PZP acts as an iron chelator, and we present evidence that the compound restricts mycobacterial growth by chelating intrabacterial iron. Thus, we have unraveled the unexpected mechanism of a novel antimycobacterial compound.

  7. Hydroxyurea could be a good clinically relevant iron chelator.

    Directory of Open Access Journals (Sweden)

    Khushnooma Italia

    Full Text Available Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

  8. Μethods of iron chelation therapy: a bibliographic review

    Directory of Open Access Journals (Sweden)

    Maria Agapiou

    2012-01-01

    Full Text Available "Iron Chelation Therapy" is a term used to describe the procedure of removing excess iron from the body, which is applied after a total of approximately 20 blood transfusions or when serum ferritin levels rise above 1000 ng/ml. Aim: The purpose of the present paper is a retrospective search in bibliography, concerning the methods of iron chelation treatment for patients with hemochromatosis owing to their undergoing multiple blood transfusions. Method: The methology followed, included the search for review and research studies, in electronic databases as well as scientific haematology journals, mostly regarding recent entries in greek and international bibliography. Results: According to the bibliography, chelation therapy compounds have significantly changed the patients' clinical features and have substantially improved their quality of life, along with their outcome over time. However, the level of patient compliance to treatment still remains the basic problem of iron chelation therapy. Conclusions: Even though the discovery of orally administered chelating agents can qualify as an auspicious accomplishment, research fields should cover a much wider spectrum, in order to improve the effectiveness of iron chelation treatment.

  9. Iron chelator daphnetin against Pneumocystis carinii in vitro

    Institute of Scientific and Technical Information of China (English)

    叶彬; 郑玉强; 武卫华; 张静

    2004-01-01

    Background Although there are several drugs and drug combinations for the treatment of Pneumocystis carinii (P. carinii) pneumonia, all drugs have the toxicity as well as low efficacy. Iron chelators have been proposed as a source of new drugs for combating these infections. We hypothesized that iron chelators would suppress the growth of P. carinii by deprivation of the nutritional iron required for growth. In this study, a short-term axenic culture system of P. carinii was established. Daphnetin (7,8-dihydroxycoumarin), a known iron chelator, was demonstrated to exhibit in vitro activity against P. carinii in this system. Methods P. carinii organisms were obtained from the lungs of immunosuppressed rats. The culture system consisted of Iscove Dulbecco Eagle's Minimum Essential Medium (IMDM), supplemented with S-adenosyl-L-methionine, N-acetylglucosamine, putrescine, L-cysteine, L-glutamine, 2-mercaptoethanol, and fetal bovine serum, and was maintained at 37℃, in 5% CO2, 95% O2, at the optimal pH of 8.0. The culture system was used to assess the effect of daphnetin on the proliferation of P. carinii organisms. The ultrastructures of the treated organisms were observed by transmission electron microscopy.Conclusions Daphnetin can suppress the growth of P. carinii in vitro. The efficacy of daphnetin in suppressing the the growth of P. carinii in vitro is related to its ability to chelate iron.

  10. Mixed ligand complexes of cobalt(III) and iron(III) containing N2O2-chelating Schiff base: Synthesis, characterisation, antimicrobial activity, antioxidant and DFT study

    Science.gov (United States)

    Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh; Bhattacharjee, Chira R.

    2015-11-01

    Six mixed ligand complexes, namely, [Co(acac)L1] (1), [Fe(acac)L1] (2), [Co(acac)L2] (3), [Fe(acac)L2] (4), [Co(acac)L3] (5), and [Fe(acac)L3] (6) (H2L1 = NN/-bis(salicylidene)-trans 1,2 diaminocyclohexane, H2L2 = NN/-bis(salicylidene)-1,2 phenylenediamine, H2L3 = NN/-bis(salicylidene)-4-methyl-1,2-phenylenediamine) were synthesised and characterized using elemental analysis, IR spectra, UV-Vis spectra, mass spectra, magnetic susceptibility measurements, 1H and 13C NMR spectroscopy, thermogravimetric analysis. The molar conductance measurement confirmed the non-electrolytic nature of the complexes in DMF solution. Antioxidant activity of the complexes was studied using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method. Biological studies of the complexes have been carried out in vitro for antimicrobial activity against some selected gram-positive and gram-negative bacteria. DFT calculations were performed using GAUSSIAN 09 program to ascertain the stable electronic structure, HOMO-LUMO energy gap, chemical hardness and dipole moment of the complexes.

  11. Management of transfusional iron overload – differential properties and efficacy of iron chelating agents

    Directory of Open Access Journals (Sweden)

    Kwiatkowski JL

    2011-09-01

    Full Text Available Janet L Kwiatkowski The Children's Hospital of Philadelphia, Division of Hematology and University of Pennsylvania School of Medicine, Philadelphia, PA, USA Abstract: Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols. These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading. Keywords: transfusion, iron, chelation, magnetic resonance imaging

  12. Screening wheat genotypes in response to ordinary chelate and nano-iron chelate fertilizers in nutrient solution

    Directory of Open Access Journals (Sweden)

    S. Omidi Nargesi

    2015-11-01

    Full Text Available Recently, attentions have been taken on the investigations regarding the use of nano-sized compounds in different fields including agricultural sector. Due to the importance of evaluating the fate and operation of nano-particles in plant systems, in this survey, responses of 13 wheat genotypes to the effect of nano-iron chelate fertilizer in the Hoagland solution under the conditions of ordinary iron chelate and nano-iron chelate, with concentration of 22.5 mg/L, was studied. This experiment was carried out in Research Greenhouse of Soilless Culture Research Center, Isfahan University of Technology, Iran, in the spring of 2013. Results showed that there were considerable positive and negative variations among wheat genotypes in response to application of nano-sized iron chelate fertilizer. Under the application of iron chelate, among the different measured traits, number of tillers and root/shoot ratio had the highest coefficient of variations, and the lowest values were observed for chlorophyll flourescence and green leaf surface. Under the application of nano-iron chelate, number of tillers and root/shoot ratio had the highest coefficient of variations, and the lowest value was observed for chlorophyll flourescence content. Nano-iron chelate fertilizer caused reduction of average dry matter yield of shoots, leaf area and root volume by 14.1, 9.5 and 8.9 percent, respectively, and increased root/shoot ratio by 13.7% for some wheat varieties, in comparison with the ordinary iron chelate. In response to nano-iron chelate fertilizer, compared to ordinary iron chelate, Line-9-shoory produced the highest total dry matter (14.49% increase and Star variety had the lowest total dry matter (-51.82%.

  13. Deferasirox, an oral chelator in the treatment of iron overload

    Directory of Open Access Journals (Sweden)

    I. Portioli

    2013-05-01

    Full Text Available BACKGROUND Deferasirox is a once-daily oral iron chelator developed for treating iron overload complicating long-term transfusion therapy in patients with diseases such as beta-thalassemia and myelodysplastic syndromes. Iron overload can damage the liver, pancreas and the heart. Deferoxamine, the only other drug approved for iron chelation, can prevent these effects but requires parenteral administration. Deferasirox has been approved after a one-year, open-label trial in patients ≥ 2 years old with beta-thalassemia and transfusional emosiderosis randomized to once-daily oral 5, 10, 20, 30 mg/kg/day in comparison of subcutaneous deferoxamine 20-60 mg/mg/kg/day x 5/week. CONCLUSIONS Deferasirox 20-30 mg/kg/day produced reductions in liver iron concentration (LIC similar to those with deferoxamine. Adverse effect of deferasirox (increases of serum creatinine and aminotransferases, including the gastrointestinal ones, are similar but more frequent than those occurring with deferoxamine. Information is lacking on the effects of deferasirox on cardiac iron and cardiac dysfunction which is the most serious complication of transfusional iron overload.

  14. Meta-analysis of the safety of iron chelating agents

    OpenAIRE

    Li, Niya; 李妮婭

    2014-01-01

    Background: Thalassaemia is a genetic disorder disease, one of the most clinically relevant haemoglobinopathies in paediatric population. It interferes with the synthesis of haemoglobin chain. For the sake of maintaining the serum haemoglobin at a normal level, regular blood cell transfusion is required to the patients with thalassaemia. In general, patients with thalassaemia are often diagnosed at an early age and need to take a life-long iron chelating therapy to prevent the multi-organ...

  15. Screening wheat genotypes in response to ordinary chelate and nano-iron chelate fertilizers in nutrient solution

    OpenAIRE

    S. Omidi Nargesi; Zahedi, M; H.R. Eshghizadeh; A.H. Khoshgoftarmanesh

    2015-01-01

    Recently, attentions have been taken on the investigations regarding the use of nano-sized compounds in different fields including agricultural sector. Due to the importance of evaluating the fate and operation of nano-particles in plant systems, in this survey, responses of 13 wheat genotypes to the effect of nano-iron chelate fertilizer in the Hoagland solution under the conditions of ordinary iron chelate and nano-iron chelate, with concentration of 22.5 mg/L, was studied. This experiment ...

  16. Antibacterial and antibiofilm effects of iron chelators against Prevotella intermedia.

    Science.gov (United States)

    Moon, Ji-Hoi; Kim, Cheul; Lee, Hee-Su; Kim, Sung-Woon; Lee, Jin-Yong

    2013-09-01

    Prevotella intermedia, a major periodontopathogen, has been shown to be resistant to many antibiotics. In the present study, we examined the effect of the FDA-approved iron chelators deferoxamine (DFO) and deferasirox (DFRA) against planktonic and biofilm cells of P. intermedia in order to evaluate the possibility of using these iron chelators as alternative control agents against P. intermedia. DFRA showed strong antimicrobial activity (MIC and MBC values of 0.16 mg ml(-1)) against planktonic P. intermedia. At subMICs, DFRA partially inhibited the bacterial growth and considerably prolonged the bacterial doubling time. DFO was unable to completely inhibit the bacterial growth in the concentration range tested and was not bactericidal. Crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that DFRA significantly decreased the biofilm-forming activity as well as the biofilm formation, while DFO was less effective. DFRA was chosen for further study. In the ATP-bioluminescent assay, which reflects viable cell counts, subMICs of DFRA significantly decreased the bioactivity of biofilms in a concentration-dependent manner. Under the scanning electron microscope, P. intermedia cells in DFRA-treated biofilm were significantly elongated compared to those in untreated biofilm. Further experiments are necessary to show that iron chelators may be used as a therapeutic agent for periodontal disease. PMID:23329319

  17. Performance of Nonmigratory Iron Chelating Active Packaging Materials in Viscous Model Food Systems.

    Science.gov (United States)

    Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-09-01

    Many packaged food products undergo quality deterioration due to iron promoted oxidative reactions. Recently, we have developed a nonmigratory iron chelating active packaging material that represents a novel approach to inhibit oxidation of foods while addressing consumer demands for "cleanˮ labels. A challenge to the field of nonmigratory active packaging is ensuring that surface-immobilized active agents retain activity in a true food system despite diffusional limitations. Yet, the relationship between food viscosity and nonmigratory active packaging activity retention has never been characterized. The objective of this study was to investigate the influence of food viscosity on iron chelation by a nonmigratory iron chelating active packaging material. Methyl cellulose was added to aqueous buffered iron solutions to yield model systems with viscosities ranging from ∼1 to ∼10(5)  mPa·s, representing viscosities ranging from beverage to mayonnaise. Iron chelation was quantified by material-bound iron content using colorimetry and inductively coupled plasma-optical emission spectrometry (ICP-OES).  Maximum iron chelation was reached in solutions up to viscosity ∼10(2)  mPa·s. In more viscous solutions (up to ∼10(4)  mPa·s), there was a significant decrease in iron chelating capacity (P influence of different food hydrocolloids on the performance of nonmigratory iron chelating active packaging was characterized. Methyl cellulose and carrageenan did not compete with the material for specific iron chelation (P > 0.05). Materials retained 32% to 45% chelating capacity when in contact with competitively chelating hydrocolloids guar gum, locust bean gum, and xanthan gum. This work demonstrates the potential application of nonmigratory iron chelating active packaging in liquid and semi-liquid foods to allow for the removal of synthetic chelators, while maintaining food quality.

  18. Curcumin inhibits growth of Saccharomyces cerevisiae through iron chelation.

    Science.gov (United States)

    Minear, Steven; O'Donnell, Allyson F; Ballew, Anna; Giaever, Guri; Nislow, Corey; Stearns, Tim; Cyert, Martha S

    2011-11-01

    Curcumin, a polyphenol derived from turmeric, is an ancient therapeutic used in India for centuries to treat a wide array of ailments. Interest in curcumin has increased recently, with ongoing clinical trials exploring curcumin as an anticancer therapy and as a protectant against neurodegenerative diseases. In vitro, curcumin chelates metal ions. However, although diverse physiological effects have been documented for this compound, curcumin's mechanism of action on mammalian cells remains unclear. This study uses yeast as a model eukaryotic system to dissect the biological activity of curcumin. We found that yeast mutants lacking genes required for iron and copper homeostasis are hypersensitive to curcumin and that iron supplementation rescues this sensitivity. Curcumin penetrates yeast cells, concentrates in the endoplasmic reticulum (ER) membranes, and reduces the intracellular iron pool. Curcumin-treated, iron-starved cultures are enriched in unbudded cells, suggesting that the G(1) phase of the cell cycle is lengthened. A delay in cell cycle progression could, in part, explain the antitumorigenic properties associated with curcumin. We also demonstrate that curcumin causes a growth lag in cultured human cells that is remediated by the addition of exogenous iron. These findings suggest that curcumin-induced iron starvation is conserved from yeast to humans and underlies curcumin's medicinal properties.

  19. Ascorbate status modulates reticuloendothelial iron stores and response to deferasirox iron chelation in ascorbate-deficient rats

    DEFF Research Database (Denmark)

    Brewer, Casey; Otto-Duessel, Maya; Lykkesfeldt, Jens;

    2012-01-01

    Iron chelation is essential to patients on chronic blood transfusions to prevent toxicity from iron overload and remove excess iron. Deferasirox (DFX) is the most commonly used iron chelator in the United States; however, some patients are relatively refractory to DFX therapy. We postulated...... weeks. Cardiac and liver iron levels were measured after iron loading (n = 18), 12 weeks of sham chelation (n = 18), and 12 weeks of DFX chelation (n = 18) at 75 mg/kg/day. Ascorbate supplementation of 150 ppm, 900 ppm, and 2250 ppm was used in the chow to mimic a broad range of ascorbate status; plasma...... 12 weeks of sham chelation. Most importantly, ascorbate supplementation at 2250 ppm improved DFX efficiency, allowing DFX to remove 21% more hepatic iron than ascorbate supplementation with 900 ppm or 150 ppm (p

  20. Development of Iron-Chelating Poly(ethylene terephthalate) Packaging for Inhibiting Lipid Oxidation in Oil-in-Water Emulsions.

    Science.gov (United States)

    Johnson, David R; Tian, Fang; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-05-27

    Foods such as bulk oils, salad dressings, and nutritionally fortified beverages that are susceptible to oxidative degradation are often packaged in poly(ethylene terephthalate) (PET) bottles with metal chelators added to the food to maintain product quality. In the present work, a metal-chelating active packaging material is designed and characterized, in which poly(hydroxamic acid) (PHA) metal-chelating moieties were grafted from the surface of PET. Biomimetic PHA groups were grafted in a two-step UV-initiated process without the use of a photoinitiator. Surface characterization of the films by attenuated total reflective Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) suggested successful grafting and conversion of poly(hydroxyethyl acrylate) (PHEA) to PHA chelating moieties from the surface of PET. Colorimetric (ferrozine) and inductively coupled plasma mass spectroscopy (ICP-MS) assays demonstrated the ability of PET-g-PHA to chelate iron in a low-pH (3.0) environment containing a competitive metal chelator (citric acid). Lipid oxidation studies demonstrated the antioxidant activity of PET-g-PHA films in inhibiting iron-promoted oxidation in an acidified oil-in-water (O/W) emulsion model system (pH 3.0). Particle size and ζ-potential analysis indicated that the addition of PET-g-PHA films did not affect the physical stability of the emulsion system. This work suggests that biomimetic chelating moieties can be grafted from PET and effectively inhibit iron-promoted degradation reactions, enabling removal of metal-chelating additives from product formulations. PMID:25985711

  1. Using iron chelating agents to enhance dermatological PDT

    Science.gov (United States)

    Curnow, Alison; Dogra, Yuktee; Winyard, Paul; Campbell, Sandra

    2009-06-01

    Topical protoporphyrin IX (PPIX) induced photodynamic therapy (PDT) of basal cell carcinoma (BCC) produces good clinical outcomes with excellent cosmesis as long as the disease remains superficial. Efficacy for nodular BCC however appears inferior to standard treatment unless repeat treatments are performed. Enhancement is therefore required and is possible by employing iron chelating agents to temporarily increase PPIX accumulation above the levels normally obtained using aminolevulinic acid (ALA) or the methyl ester of ALA (MAL) alone. In vitro studies investigated the effect of the novel iron chelator, CP94 on necrotic or apoptotic cell death in cultured human skin fibroblasts and epidermal carcinoma cells incubated with MAL. Furthermore, following a dose escalating safety study conducted with ALA in patients, an additional twelve nodular BCCs were recruited for topical treatment with standard MAL-PDT +/- increasing doses of CP94. Six weeks later following clinical assessment, the whole treatment site was excised for histological analysis. CP94 produced greater cell death in vitro when administered in conjunction with MAL than this porphyrin precursor could produce when administered alone. Clinically, PDT treatment using Metvix + CP94 was a simple and safe modification associated with a trend of reduced tumor thickness with increasing CP94 dose.

  2. Natural iron chelators: Protective role in A549 cells of flavonoids-rich extracts of Citrus juices in Fe(3+)-induced oxidative stress.

    Science.gov (United States)

    Ferlazzo, Nadia; Visalli, Giuseppa; Cirmi, Santa; Lombardo, Giovanni Enrico; Laganà, Pasqualina; Di Pietro, Angela; Navarra, Michele

    2016-04-01

    Exogenous iron in particulate matter and imbalanced iron homeostasis cause deleterious effects on health. Natural and synthetic iron chelators may be of therapeutic benefit, therefore we evaluated the protective effect of Citrus flavonoids-rich extracts from bergamot and orange juices in iron overloaded human lung epithelial cells. Cytofluorimetric, biochemical and genotoxic analyses were performed in Fe2(SO4)3 exposed A549, pretreated with each extract whose chemical composition was previously detected. Chelating activity was assessed in cells by a calcein ester. Both extracts reduced the generation of reactive oxygen species and membrane lipid peroxidation, improved mitochondrial functionality, and prevented DNA-oxidative damage in iron-exposed cells. Antioxidant effects were attributed to the chelating property, blocking upstream the redox activity of iron. Flavonoid-rich extracts also induced antioxidant catalase. The bergamot and orange juice extracts had a broad-spectrum protective effect. Their use prevents iron oxidative injury and these natural iron chelators could be used as therapeutic agents. PMID:27037654

  3. Curcumin, a cancer chemopreventive and chemotherapeutic agent, is a biologically active iron chelator

    OpenAIRE

    Jiao, Yan; Wilkinson, John; Di, Xiumin; Wang, Wei; Hatcher, Heather; Kock, Nancy D.; D'Agostino, Ralph; Knovich, Mary Ann; Torti, Frank M; Suzy V Torti

    2009-01-01

    Curcumin is a natural product currently in human clinical trials for a variety of neoplastic, preneoplastic, and inflammatory conditions. We previously observed that, in cultured cells, curcumin exhibits properties of an iron chelator. To test whether the chelator activity of curcumin is sufficient to induce iron deficiency in vivo, mice were placed on diets containing graded concentrations of both iron and curcumin for 26 weeks. Mice receiving the lowest level of dietary iron exhibited borde...

  4. MRI guided iron assessment and oral chelator use improve iron status in thalassemia major patients.

    Science.gov (United States)

    Nichols-Vinueza, Diana X; White, Matthew T; Powell, Andrew J; Banka, Puja; Neufeld, Ellis J

    2014-07-01

    Oral iron chelators and magnetic resonance imaging (MRI) assessment of heart and liver iron burden have become widely available since the mid 2000s, allowing for improved patient compliance with chelation and noninvasive monitoring of iron levels for titration of therapy. We evaluated the impact of these changes in our center for patients with thalassemia major and transfusional iron overload. This single center, retrospective observational study covered the period from 2005 through 2012. Liver iron content (LIC) was estimated both by a T2* method and by R2 (Ferriscan® ) technique. Cardiac iron was assessed as cT2*. Forty-two patients (55% male) with transfused thalassemia and at least two MRIs were included (median age at first MRI, 17.5 y). Over a mean follow-up period of 5.2 ± 1.9 y, 190 MRIs were performed (median 4.5 per patient). Comparing baseline to last MRI, 63% of patients remained within target ranges for cT2* and LIC, and 13% improved from high values to the target range. Both the median LIC and cT2* (cR2* = 1000/cT2*) status improved over time: LIC 7.3 to 4.5 mg/g dry weight, P = 0.0004; cR2* 33.4 to 28.3 Hz, P = 0.01. Individual responses varied widely. Two patients died of heart failure during the study period. Annual MRI iron assessments and availability of oral chelators both facilitate changes in chelation dose and strategies to optimize care. PMID:24652616

  5. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    OpenAIRE

    Leitch, Heather A.; Vickars, Linda M.; Chase, Jocelyn M.; Badawi, Maha A.

    2010-01-01

    Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC). A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the ...

  6. Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

    Science.gov (United States)

    Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

    2002-12-18

    Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time. PMID:12475278

  7. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    Directory of Open Access Journals (Sweden)

    Maha A. Badawi

    2010-01-01

    Full Text Available Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC. A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the same time course, ferritin levels decreased but did not normalize. There have been eighteen other MDS patients reported showing improvement in hemoglobin level with iron chelation; nine became transfusion independent, nine had decreased transfusion requirements, and some showed improved trilineage myelopoiesis. The clinical features of these patients are summarized and possible mechanisms for such an effect of iron chelation on cytopenias are discussed.

  8. Intracellular reduction/activation of a disulfide switch in thiosemicarbazone iron chelators

    OpenAIRE

    Akam, Eman A.; Chang, Tsuhen M.; Astashkin, Andrei V.; Tomat, Elisa

    2014-01-01

    Iron scavengers (chelators) offer therapeutic opportunities in anticancer drug design by targeting the increased demand for iron in cancer cells as compared to normal cells. Prochelation approaches are expected to avoid systemic iron depletion as chelators are liberated under specific intracellular conditions. In the strategy described herein, a disulfide linkage is employed as a redox-directed switch within the binding unit of an antiproliferative thiosemicarbazone prochelator, which is acti...

  9. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    Science.gov (United States)

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life. PMID:26593563

  10. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    Science.gov (United States)

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life.

  11. Translational downregulation of HSP90 expression by iron chelators in neuroblastoma cells.

    Science.gov (United States)

    Sidarovich, Viktoryia; Adami, Valentina; Gatto, Pamela; Greco, Valentina; Tebaldi, Toma; Tonini, Gian Paolo; Quattrone, Alessandro

    2015-01-01

    Iron is an essential cellular nutrient, being a critical cofactor of several proteins involved in cell growth and replication. Compared with normal cells, neoplastic cells have been shown to require a greater amount of iron, thus laying the basis for the promising anticancer activity of iron chelators. In this work, we evaluated the effects of molecules with iron chelation activity on neuroblastoma (NB) cell lines. Of the 17 iron chelators tested, six reduced cell viability of two NB cell lines with an inhibition of growth of 50% below 10 µM; four of the six molecules-ciclopirox olamine (CPX), piroctone, 8-hydroxyquinoline, and deferasirox-were also shown to efficiently chelate intracellular iron within minutes after addition. Effects on cell viability of one of the compounds, CPX, were indeed dependent on chelation of intracellular iron and mediated by both G0/G1 cell cycle block and induction of apoptosis. By combined transcriptome and translatome profiling we identified early translational downregulation of several members of the heat shock protein group as a specific effect of CPX treatment. We functionally confirmed iron-dependent depletion of HSP90 and its client proteins at pharmacologically achievable concentrations of CPX, and we extended this effect to piroctone, 8-hydroxyquinoline, and deferasirox. Given the documented sensitivity of NB cells to HSP90 inhibition, we propose CPX and other iron chelators as investigational antitumor agents in NB therapy. PMID:25564462

  12. Generation, Fractionation, and Characterization of Iron-Chelating Protein Hydrolysate from Palm Kernel Cake Proteins.

    Science.gov (United States)

    Zarei, Mohammad; Ghanbari, Rahele; Tajabadi, Naser; Abdul-Hamid, Azizah; Bakar, Fatimah Abu; Saari, Nazamid

    2016-02-01

    Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron-chelating activity of each hydrolysate were evaluated using O-phthaldialdehyde-based spectrophotometric method and ferrozine-based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron-chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron-chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain-generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron-chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron-chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain-generated peptides, GGIF and YLLLK showed among the highest iron-chelating activities of 56% and 53%, whereas their IC50 were 1.4 and 0.2 μM, respectively. PMID:26720491

  13. Generation, Fractionation, and Characterization of Iron-Chelating Protein Hydrolysate from Palm Kernel Cake Proteins.

    Science.gov (United States)

    Zarei, Mohammad; Ghanbari, Rahele; Tajabadi, Naser; Abdul-Hamid, Azizah; Bakar, Fatimah Abu; Saari, Nazamid

    2016-02-01

    Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron-chelating activity of each hydrolysate were evaluated using O-phthaldialdehyde-based spectrophotometric method and ferrozine-based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron-chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron-chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain-generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron-chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron-chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain-generated peptides, GGIF and YLLLK showed among the highest iron-chelating activities of 56% and 53%, whereas their IC50 were 1.4 and 0.2 μM, respectively.

  14. Antioxidant Activity of Caffeic Acid against Iron-Induced Free Radical Generation—A Chemical Approach

    Science.gov (United States)

    Genaro-Mattos, Thiago C.; Maurício, Ângelo Q.; Rettori, Daniel; Alonso, Antonio; Hermes-Lima, Marcelo

    2015-01-01

    Caffeic acid (CA) is a phenolic compound widely found in coffee beans with known beneficial effects in vivo. Many studies showed that CA has anti-inflammatory, anti-mutagenic, antibacterial and anti-carcinogenic properties, which could be linked to its antioxidant activity. Taking in consideration the reported in vitro antioxidant mechanism of other polyphenols, our working hypothesis was that the CA antioxidant activity could be related to its metal-chelating property. With that in mind, we sought to investigate the chemical antioxidant mechanism of CA against in vitro iron-induced oxidative damage under different assay conditions. CA was able to prevent hydroxyl radical formation promoted by the classical Fenton reaction, as determined by 2-deoxyribose (2-DR) oxidative degradation and DMPO hydroxylation. In addition to its ability to prevent hydroxyl radical formation, CA had a great inhibition of membrane lipid peroxidation. In the lipid peroxidation assays CA acted as both metal-chelator and as hydrogen donor, preventing the deleterious action promoted by lipid-derived peroxyl and alkoxyl radicals. Our results indicate that the observed antioxidant effects were mostly due to the formation of iron-CA complexes, which are able to prevent 2-DR oxidation and DMPO hydroxylation. Noteworthy, the formation of iron-CA complexes and prevention of oxidative damage was directly related to the pH of the medium, showing better antioxidant activity at higher pH values. Moreover, in the presence of lipid membranes the antioxidant potency of CA was much higher, indicating its enhanced effectiveness in a hydrophobic environment. Overall, our results show that CA acts as an antioxidant through an iron chelating mechanism, preventing the formation of free hydroxyl radicals and, therefore, inhibiting Fenton-induced oxidative damage. The chemical properties of CA described here—in association with its reported signaling effects—could be an explanation to its beneficial effects

  15. Antioxidant Activity of Caffeic Acid against Iron-Induced Free Radical Generation--A Chemical Approach.

    Directory of Open Access Journals (Sweden)

    Thiago C Genaro-Mattos

    Full Text Available Caffeic acid (CA is a phenolic compound widely found in coffee beans with known beneficial effects in vivo. Many studies showed that CA has anti-inflammatory, anti-mutagenic, antibacterial and anti-carcinogenic properties, which could be linked to its antioxidant activity. Taking in consideration the reported in vitro antioxidant mechanism of other polyphenols, our working hypothesis was that the CA antioxidant activity could be related to its metal-chelating property. With that in mind, we sought to investigate the chemical antioxidant mechanism of CA against in vitro iron-induced oxidative damage under different assay conditions. CA was able to prevent hydroxyl radical formation promoted by the classical Fenton reaction, as determined by 2-deoxyribose (2-DR oxidative degradation and DMPO hydroxylation. In addition to its ability to prevent hydroxyl radical formation, CA had a great inhibition of membrane lipid peroxidation. In the lipid peroxidation assays CA acted as both metal-chelator and as hydrogen donor, preventing the deleterious action promoted by lipid-derived peroxyl and alkoxyl radicals. Our results indicate that the observed antioxidant effects were mostly due to the formation of iron-CA complexes, which are able to prevent 2-DR oxidation and DMPO hydroxylation. Noteworthy, the formation of iron-CA complexes and prevention of oxidative damage was directly related to the pH of the medium, showing better antioxidant activity at higher pH values. Moreover, in the presence of lipid membranes the antioxidant potency of CA was much higher, indicating its enhanced effectiveness in a hydrophobic environment. Overall, our results show that CA acts as an antioxidant through an iron chelating mechanism, preventing the formation of free hydroxyl radicals and, therefore, inhibiting Fenton-induced oxidative damage. The chemical properties of CA described here--in association with its reported signaling effects--could be an explanation to its

  16. A study of intracellular iron metabolism using pyridoxal isonicotinoyl hydrazone and other synthetic chelating agents

    International Nuclear Information System (INIS)

    Rabbit reticulocytes with a high level of non-heme radioiron induced by preincubation with isonicotinic acid hydrazide and transferrin-bound 59Fe, were reincubated with various synthetic chelating agents and the amount of radioiron released from the cells was determined. Some substances, especially derivatives of pyridoxal or 2-hydroxybenzaldehyde and isonicotinic acid hydrazide or benzhydrazide, were found to mobilize significantly iron from 59Fe-labelled reticulocytes. Iron mobilizaiton from reticulocytes by pyridoxal isonicotinoyl hydrazone requires ATP to be produced by cells and is completely blocked by low temperatute (40C). Although the effect of desferrioxamine is also prevented by low temperature, modest iron mobilization due to this chelator seems to occur independently of ATP production in reticulocytes. Pyridoxal isonicotinoyl hydrazone mobilized iron mainly from mitochondria and in part also from ferritin. Although 2,2'-bipyridine seems to enter reticulocyte mitochondria and bind iron there, this chelator is not able to relaease iron either from mitochondria or from the cells. Reticulocytes with a high level of non-heme radioiron are envisaged as a useful system for testing biological effectiveness of various iron chelators. Pyridoxal isonicotinoyl hydrazone was shown to be an effective in vivo chelator since its adminstration to mice decreased 59Fe radioactivity in liver, spleen and kidney. (Auth.)

  17. The Management of Iron Chelation Therapy: Preliminary Data from a National Registry of Thalassaemic Patients

    Directory of Open Access Journals (Sweden)

    Adriana Ceci

    2011-01-01

    Full Text Available Thalassaemia and other haemoglobinopathies constitute an important health problem in Mediterranean countries, placing a tremendous emotional, psychological, and economic burden on their National Health systems. The development of new chelators in the most recent years had a major impact on the treatment of thalassaemia and on the quality of life of thalassaemic patients. A new initiative was promoted by the Italian Ministry of Health, establishing a Registry for thalassaemic patients to serve as a tool for the development of cost-effective diagnostic and therapeutic approaches and for the definition of guidelines supporting the most appropriate management of the iron-chelating therapy and a correct use of the available iron-chelating agents. This study represents the analysis of the preliminary data collected for the evaluation of current status of the iron chelation practice in the Italian thalassaemic population and describes how therapeutic interventions can widely differ in the different patients' age groups.

  18. Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

    Science.gov (United States)

    Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

    2016-10-01

    Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. PMID:27474467

  19. Effect of the chelation of metal cation on the antioxidant activity of chondroitin sulfates.

    Science.gov (United States)

    Ajisaka, Katsumi; Oyanagi, Yutaka; Miyazaki, Tatsuo; Suzuki, Yasuhiro

    2016-06-01

    The antioxidant potencies of chondroitin sulfates (CSs) from shark cartilage, salmon cartilage, bovine trachea, and porcine intestinal mucosa were compared by three representative methods for the measurement of the antioxidant activity; DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity. CSs from salmon cartilage and bovine trachea showed higher potency in comparison with CSs from shark cartilage and porcine intestinal mucosa. Next, CS from salmon cartilage chelating with Ca(2+), Mg(2+), Mn(2+), or Zn(2+) were prepared, and their antioxidant potencies were compared. CS chelating with Ca(2+) or Mg(2+) ions showed rather decreased DPPH radical scavenging activity in comparison with CS of H(+) form. In contrast, CS chelating with Ca(2+) or Mg(2+) ion showed remarkably enhanced superoxide radical scavenging activity than CS of H(+) or Na(+) form. Moreover, CS chelating with divalent metal ions, Ca(2+), Mg(2+), Mn(2+), or Zn(2+), showed noticeably higher hydroxyl radical scavenging activity than CS of H(+) or Na(+) form. The present results revealed that the scavenging activities of, at least, superoxide radical and hydroxyl radical were enhanced by the chelation with divalent metal ions. PMID:26856546

  20. Intracellular reduction/activation of a disulfide switch in thiosemicarbazone iron chelators.

    Science.gov (United States)

    Akam, Eman A; Chang, Tsuhen M; Astashkin, Andrei V; Tomat, Elisa

    2014-10-01

    Iron scavengers (chelators) offer therapeutic opportunities in anticancer drug design by targeting the increased demand for iron in cancer cells as compared to normal cells. Prochelation approaches are expected to avoid systemic iron depletion as chelators are liberated under specific intracellular conditions. In the strategy described herein, a disulfide linkage is employed as a redox-directed switch within the binding unit of an antiproliferative thiosemicarbazone prochelator, which is activated for iron coordination following reduction to the thiolate chelator. In glutathione redox buffer, this reduction event occurs at physiological concentrations and half-cell potentials. Consistent with concurrent reduction and activation, higher intracellular thiol concentrations increase cell susceptibility to prochelator toxicity in cultured cancer cells. The reduction of the disulfide switch and intracellular iron chelation are confirmed in cell-based assays using calcein as a fluorescent probe for paramagnetic ions. The resulting low-spin Fe(III) complex is identified in intact Jurkat cells by EPR spectroscopy measurements, which also document a decreased concentration of active ribonucleotide reductase following exposure to the prochelator. Cell viability and fluorescence-based assays show that the iron complex presents low cytotoxicity and does not participate in intracellular redox chemistry, indicating that this antiproliferative chelation strategy does not rely on the generation of reactive oxygen species. PMID:25100578

  1. Intracellular reduction/activation of a disulfide switch in thiosemicarbazone iron chelators

    Science.gov (United States)

    Akam, Eman A.; Chang, Tsuhen M.; Astashkin, Andrei V.

    2014-01-01

    Iron scavengers (chelators) offer therapeutic opportunities in anticancer drug design by targeting the increased demand for iron in cancer cells as compared to normal cells. Prochelation approaches are expected to avoid systemic iron depletion as chelators are liberated under specific intracellular conditions. In the strategy described herein, a disulfide linkage is employed as a redox-directed switch within the binding unit of an antiproliferative thiosemicarbazone prochelator, which is activated for iron coordination following reduction to the thiolate chelator. In glutathione redox buffer, this reduction event occurs at physiological concentrations and half-cell potentials. Consistent with concurrent reduction and activation, higher intracellular thiol concentrations increase cell susceptibility to prochelator toxicity in cultured cancer cells. The reduction of the disulfide switch and intracellular iron chelation are confirmed in cell-based assays using calcein as a fluorescent probe for paramagnetic ions. The resulting low-spin Fe(III) complex is identified in intact Jurkat cells by EPR spectroscopy measurements, which also document a decreased concentration of active ribonucleotide reductase following exposure to the prochelator. Cell viability and fluorescence-based assays show that the iron complex presents low cytotoxicity and does not participate in intracellular redox chemistry, indicating that this antiproliferative chelation strategy does not rely on the generation of reactive oxygen species. PMID:25100578

  2. Function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2+, demonstrating that the substance may serve as a ferric chelator, oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the β-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more acces- sible to degradation.

  3. Function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation

    Institute of Scientific and Technical Information of China (English)

    WANG Lu; YAN WenChao; CHEN JiaChuan; HUANG Feng; GAO PeiJi

    2008-01-01

    An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2+, demonstrating that the substance may serve as a ferric chelator,oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the β-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more accessible to degradation.

  4. Yerba mate (Ilex paraguariensis St. Hill.)-based beverages: How successive extraction influences the extract composition and its capacity to chelate iron and scavenge free radicals.

    Science.gov (United States)

    Colpo, Ana C; Rosa, Hemerson; Lima, Maria Eduarda; Pazzini, Camila Eliza F; de Camargo, Vanessa B; Bassante, Felipa E M; Puntel, Robson; Ávila, Daiana Silva; Mendez, Andreas; Folmer, Vanderlei

    2016-10-15

    Chimarrão or mate is a popular beverage from South America that is drank with successive infusions. Although yerba mate extracts have been widely studied, few studies have described the extract contents in beverages. Using yerba mate samples from Brazil, Argentina, and Uruguay, we examined the extract chromatographic profiles, total polyphenol content and their capacities to chelate iron. In addition, we analyzed antioxidant activity by examining the ability of the extracts to scavenge DPPH and NO. Our results showed that the amount of extracted compound was highest in yerba mate extract from Uruguay, followed by Argentina, then Brazil. Herbs from all three areas had a significant capacity to inhibit DPPH and NO free radicals. The Brazilian and Uruguayan herbs had an 80% iron chelation capacity (pchelation capacity of the Argentinean herb was lower but still significant (p⩽0.05). We conclude that the compound concentration decreases with successive extractions, while the antioxidant capacity is maintained at significant levels.

  5. Yerba mate (Ilex paraguariensis St. Hill.)-based beverages: How successive extraction influences the extract composition and its capacity to chelate iron and scavenge free radicals.

    Science.gov (United States)

    Colpo, Ana C; Rosa, Hemerson; Lima, Maria Eduarda; Pazzini, Camila Eliza F; de Camargo, Vanessa B; Bassante, Felipa E M; Puntel, Robson; Ávila, Daiana Silva; Mendez, Andreas; Folmer, Vanderlei

    2016-10-15

    Chimarrão or mate is a popular beverage from South America that is drank with successive infusions. Although yerba mate extracts have been widely studied, few studies have described the extract contents in beverages. Using yerba mate samples from Brazil, Argentina, and Uruguay, we examined the extract chromatographic profiles, total polyphenol content and their capacities to chelate iron. In addition, we analyzed antioxidant activity by examining the ability of the extracts to scavenge DPPH and NO. Our results showed that the amount of extracted compound was highest in yerba mate extract from Uruguay, followed by Argentina, then Brazil. Herbs from all three areas had a significant capacity to inhibit DPPH and NO free radicals. The Brazilian and Uruguayan herbs had an 80% iron chelation capacity (pextractions, while the antioxidant capacity is maintained at significant levels. PMID:27173551

  6. Diethylentriaminepenta acetic acid glucose conjugates as a cell permeable iron chelator

    Directory of Open Access Journals (Sweden)

    Mona Mosayebnia

    2014-01-01

    Full Text Available Objective: To find out whether DTPA-DG complex can enhance clearance of intracellular free iron. Materials and Methods: Diethylenetriaminepentaacetic acid-D-deoxy-glucosamine (DTPA-DG was synthesized and examined for its activity as a cell-permeable iron chelator in human hepatocellular carcinoma (HEPG2 cell line exposed to high concentration of iron sulfate and compared with deferoxamine (DFO, a prototype iron chelator. The effect of DTPA-DG on cell viability was monitored using the 3-(4,5-dimethythiazol-2-yl-2,5-diphenyl tetrazolium bromide MTT assay as well. Results: There was a significant increase of iron level after iron overload induction in HEPG2 cell culture. DTPA-DG presented a remarkable capacity to iron burden reducing with estimated 50% inhibitory concentration value of 65.77 nM. In fact, glycosyl moiety was gained access of DTPA to intracellular iron deposits through glucose transporter systems. Conclusion: DTPA-DG, more potent than DFO to sequester deposits of free iron with no profound toxic effect. The results suggest the potential of DTPA-DG in chelating iron and permitting its excretion from primary organ storage.

  7. Arsenic induced oxidative stress and the role of antioxidant supplementation during chelation: a review.

    Science.gov (United States)

    Flora, S J S; Bhadauria, Smrati; Kannan, G M; Singh, Nutan

    2007-04-01

    Arsenic is a naturally occurring metalloid, ubiquitously present in the environment in both organic and inorganic forms. Arsenic contamination of groundwater in the West Bengal basin in India is unfolding as one of the worst natural geoenvironmental disaster to date. Chronic exposure of humans to high concentration of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, Blackfoot disease and high risk of cancer The underlying mechanism of toxicity includes the interaction with the sulphydryl groups and the generation of reactive oxygen species leading to oxidative stress. Chelation therapy with chelating agents like British Anti Lewisite (BAL), sodium 2,3-dimercaptopropane 1-sulfonate (DMPS), meso 2,3 dimercaptosuccinic acid (DMSA) etc., is considered to be the best known treatment against arsenic poisoning. The treatment with these chelating agents however is compromised with certain serious drawbacks/side effects. The studies show that supplementation of antioxidants along with a chelating agent prove to be a better treatment regimen. This review attempts to provide the readers with a comprehensive account of recent developments in the research on arsenic poisoning particularly the role of oxidative stress/free radicals in the toxic manifestation, an update about the recent strategies for the treatment with chelating agents and a possible beneficial role of antioxidants supplementation to achieve the optimum effects.

  8. The Effect of Chelating Copolymer Additive on the Yttrium Iron Garnet Nanoparticle Formation

    Institute of Scientific and Technical Information of China (English)

    Wang; Cheng-chien

    2007-01-01

    1 Results Yttrium iron garnet (YIG) is a well-known ferromagnetic garnet material and has widely used in electronic devices[1].A new acrylic chelating polymer was developed to act as the additive of the preparation of YIG precursor in our previous study[2].The sintering temperature of YIG nanocrystal obtained by this YIG precursor (ACP) was magnificently descended from 1 000 to 600 ℃.In this study,we were further to study the effect of amount of chelating polymer and the compositions of chelating polyme...

  9. Toxicity of chelated iron (Fe-DTPA) in American cranberry

    Science.gov (United States)

    American cranberry (Vaccinium macrocarpon) is naturally adapted to environments with high concentrations of soluble iron. Yet, there is a need to further explore iron nutrition in cranberry given concerns of toxicity problems from irrigation with iron-rich water. This study investigated the threat o...

  10. DCCP and DICP: Construction and Analyses of Databases for Copper- and Iron-Chelating Proteins

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Yan Yang; Sheng-Juan Jiang; Ling-Ling Chen; Hai-Xia Gao; Qing-Shan Fu; Feng Li; Bin-Guang Ma; Hong-Yu Zhang

    2005-01-01

    Copper and iron play important roles in a variety of biological processes, especially when being chelated with proteins. The proteins involved in the metal binding,transporting and metabolism have aroused much interest. To facilitate the study on this topic, we constructed two databases (DCCP and DICP) containing the known copper- and iron-chelating proteins, which are freely available from the website http:∥sdbi.sdut.edu.cn/en. Users can conveniently search and browse all of the entries in the databases. Based on the two databases, bioinformatic analyses were performed, which provided some novel insights into metalloproteins.

  11. Synergistic Activities of an Efflux Pump Inhibitor and Iron Chelators against Pseudomonas aeruginosa Growth and Biofilm Formation

    DEFF Research Database (Denmark)

    Liu, Yang; Yang, Liang; Molin, Søren

    2010-01-01

    The efflux pump inhibitor phenyl-arginine-beta-naphthylamide (PA beta N) was paired with iron chelators 2,2'-dipyridyl, acetohydroxamic acid, and EDTA to assess synergistic activities against Pseudomonas aeruginosa growth and biofilm formation. All of the tested iron chelators synergistically...

  12. Iron removal from milk and other nutrient media with a chelating resin.

    Science.gov (United States)

    Feng, M; van der Does, L; Bantjes, A; de Groote, J M

    1995-01-01

    A water-insoluble iron(III)-chelating resin was used to study iron removal from milk and other nutrient media. Seventy to 85% of the iron could be removed from wine and beer with the resin, which was a crosslinked copolymer of 1-(beta-acrylamidoethyl)-3-hydroxy-2-methyl-4(1H)- pyridinone and N,N-dimethylacrylamide. Iron removal from milk was dependent on the pH of milk and on the concentration of soluble chelators added. Under the same conditions as used for the removal of iron from wine and beer, only 11 to 19% of the iron could be removed from milk. However, in combination with water-soluble chelators, the resin removed 60 to 75% of the iron from the milk. Preliminary results showed that the growth of spores of Clostridium tyrobutyricum in the treated milk was reduced. Moreover, addition of the resin and sodium bicarbonate to the milk completely inhibited the growth of the spores. PMID:7738259

  13. The Utility of Iron Chelators in the Management of Inflammatory Disorders

    Directory of Open Access Journals (Sweden)

    C. Lehmann

    2015-01-01

    Full Text Available Since iron can contribute to detrimental radical generating processes through the Fenton and Haber-Weiss reactions, it seems to be a reasonable approach to modulate iron-related pathways in inflammation. In the human organism a counterregulatory reduction in iron availability is observed during inflammatory diseases. Under pathological conditions with reduced or increased baseline iron levels different consequences regarding protection or susceptibility to inflammation have to be considered. Given the role of iron in development of inflammatory diseases, pharmaceutical agents targeting this pathway promise to improve the clinical outcome. The objective of this review is to highlight the mechanisms of iron regulation and iron chelation, and to demonstrate the potential impact of this strategy in the management of several acute and chronic inflammatory diseases, including cancer.

  14. Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

    Directory of Open Access Journals (Sweden)

    Kell Douglas B

    2009-01-01

    Full Text Available Abstract Background The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. Review We review the considerable and wide-ranging evidence for the involvement of this combination of (superoxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation. The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron molecules that are nominally antioxidants can actually act as pro

  15. A Powerful Mitochondria-Targeted Iron Chelator Affords High Photoprotection against Solar Ultraviolet A Radiation.

    Science.gov (United States)

    Reelfs, Olivier; Abbate, Vincenzo; Hider, Robert C; Pourzand, Charareh

    2016-08-01

    Mitochondria are the principal destination for labile iron, making these organelles particularly susceptible to oxidative damage on exposure to ultraviolet A (UVA, 320-400 nm), the oxidizing component of sunlight. The labile iron-mediated oxidative damage caused by UVA to mitochondria leads to necrotic cell death via adenosine triphosphate depletion. Therefore, targeted removal of mitochondrial labile iron via highly specific tools from these organelles may be an effective approach to protect the skin cells against the harmful effects of UVA. In this work, we designed a mitochondria-targeted hexadentate (tricatechol-based) iron chelator linked to mitochondria-homing SS-like peptides. The photoprotective potential of this compound against UVA-induced oxidative damage and cell death was evaluated in cultured primary skin fibroblasts. Our results show that this compound provides unprecedented protection against UVA-induced mitochondrial damage, adenosine triphosphate depletion, and the ensuing necrotic cell death in skin fibroblasts, and this effect is fully related to its potent iron-chelating property in the organelle. This mitochondria-targeted iron chelator has therefore promising potential for skin photoprotection against the deleterious effects of the UVA component of sunlight. PMID:27109868

  16. Selection of Chelated Fe (III)/Fe (II) Catalytic Oxidation Agents for Desulfurization Based on Iron Complexation Method

    Institute of Scientific and Technical Information of China (English)

    Luo Ying; Liu Youzhi; Qi Guisheng; Guo Huidong; Zhu Zhengfeng

    2014-01-01

    Optimization of factors inlfuencing the experiments on reactions involving 8 different chelating agents and sol-uble Fe (III)/Fe (II) salts was carried out to yield chelated iron complexes. A combination of optimized inlfuencing factors has resulted in a Fe chelating capacity of the iron-based desulfurization solution to be equal to 6.83-13.56 g/L at a redox potential of 0.185-0.3. The desulfurization performance of Fe (III)/Fe (II) chelating agents was investigated on a simulated sulfur-containing industrial gas composed of H2S and N2 in a cross-lfow rotating packed bed. Test results have revealed that the proposed iron-based desulfurization solution showed a sulfur removal efifciency of over 99%along with a Fe chelating capacity exceeding 1.35 g/L. This desulfurization technology which has practical application prospect is currently in the phase of commercial scale-up study.

  17. Extraction of Micronutrient Metals from Peat-based Media Using Various Chelate-ligand and Iron-source Extractants

    Science.gov (United States)

    Objectives of the study were to determine effects of chelate-ligand (experiment 1) and iron-source (experiment 2) unbuffrered extractant solutions on substrate pH and Cu, Fe, Mn, and Zn extraction from peat-based media. Chelate-ligand extractants consisted of 5 mM solutions of ethylenediaminedisucc...

  18. Antioxidant and Chelating Activity of Nontoxic Jatropha curcas L. Protein Hydrolysates Produced by In Vitro Digestion Using Pepsin and Pancreatin

    Directory of Open Access Journals (Sweden)

    Santiago Gallegos Tintoré

    2015-01-01

    Full Text Available The antioxidant and metal chelating activities in J. curcas protein hydrolysates have been determined. The hydrolysates were produced by treatment of a nontoxic genotype with the digestive enzymes pepsin and pancreatin and then were characterized by fast protein liquid chromatography and reverse phase chromatography. Peptidic fractions with higher radical scavenging activity were analysed by matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant activity was determined by measuring inhibition of the oxidative degradation of β-carotene and by measuring the reactive oxygen species (ROS in Caco-2 cell cultures. Cu2+ and Fe2+ chelating activities were also determined. The hydrolysates inhibited the degradation of β-carotene and the formation of ROS in Caco-2 cells. The lower molecular weight peptidic fractions from FPLC had stronger antioxidant activity in cell cultures compared with the hydrolysates, which correlated with a higher content in antioxidant and chelating amino acids. These fractions were characterized by a large presence of peptides with different molecular masses. The hydrolysates exhibited both Cu2+ and Fe2+ chelating activity. It was concluded that J. curcas is a good source of antioxidant and metal chelating peptides, which may have a positive impact on the economic value of this crop, as a potential source of food functional components.

  19. CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.

    Science.gov (United States)

    Tian, Qiuying; Zhang, Xinxin; Yang, An; Wang, Tianzuo; Zhang, Wen-Hao

    2016-05-01

    Iron deficiency is one of the major limiting factors affecting quality and production of crops in calcareous soils. Numerous signaling molecules and transcription factors have been demonstrated to play a regulatory role in adaptation of plants to iron deficiency. However, the mechanisms underlying the iron deficiency-induced physiological processes remain to be fully dissected. Here, we demonstrated that the protein kinase CIPK23 was involved in iron acquisition. Lesion of CIPK23 rendered Arabidopsis mutants hypersensitive to iron deficiency, as evidenced by stronger chlorosis in young leaves and lower iron concentration than wild-type plants under iron-deficient conditions by down-regulating ferric chelate reductase activity. We found that iron deficiency evoked an increase in cytosolic Ca(2+) concentration and the elevated Ca(2+) would bind to CBL1/CBL9, leading to activation of CIPK23. These novel findings highlight the involvement of calcium-dependent CBL-CIPK23 complexes in the regulation of iron acquisition. Moreover, mutation of CIPK23 led to changes in contents of mineral elements, suggesting that CBL-CIPK23 complexes could be as "nutritional sensors" to sense and regulate the mineral homeostasis in Arabisopsis. PMID:26993237

  20. CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.

    Science.gov (United States)

    Tian, Qiuying; Zhang, Xinxin; Yang, An; Wang, Tianzuo; Zhang, Wen-Hao

    2016-05-01

    Iron deficiency is one of the major limiting factors affecting quality and production of crops in calcareous soils. Numerous signaling molecules and transcription factors have been demonstrated to play a regulatory role in adaptation of plants to iron deficiency. However, the mechanisms underlying the iron deficiency-induced physiological processes remain to be fully dissected. Here, we demonstrated that the protein kinase CIPK23 was involved in iron acquisition. Lesion of CIPK23 rendered Arabidopsis mutants hypersensitive to iron deficiency, as evidenced by stronger chlorosis in young leaves and lower iron concentration than wild-type plants under iron-deficient conditions by down-regulating ferric chelate reductase activity. We found that iron deficiency evoked an increase in cytosolic Ca(2+) concentration and the elevated Ca(2+) would bind to CBL1/CBL9, leading to activation of CIPK23. These novel findings highlight the involvement of calcium-dependent CBL-CIPK23 complexes in the regulation of iron acquisition. Moreover, mutation of CIPK23 led to changes in contents of mineral elements, suggesting that CBL-CIPK23 complexes could be as "nutritional sensors" to sense and regulate the mineral homeostasis in Arabisopsis.

  1. Highly nucleophilic dipropanolamine chelated boron reagents for aryl-transmetallation to iron complexes.

    Science.gov (United States)

    Dunsford, Jay J; Clark, Ewan R; Ingleson, Michael J

    2015-12-21

    New aryl- and heteroarylboronate esters chelated by dipropanolamine are synthesised directly from boronic acids. The corresponding anionic borates are readily accessible by deprotonation and demonstrate an increase in hydrocarbyl nucleophilicity in comparison to other common borates. The new borates proved competent for magnesium or zinc additive-free, direct boron-to-iron hydrocarbyl transmetallations with well-defined iron(II) (pre)catalysts. The application of the new borate reagents in representative Csp(2)-Csp(3) cross-coupling led to almost exclusive homocoupling unless coupling is performed in the presence of a zinc additive. PMID:26554484

  2. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions

    Science.gov (United States)

    Burke, Benjamin P.; Baghdadi, Neazar; Kownacka, Alicja E.; Nigam, Shubhanchi; Clemente, Gonçalo S.; Al-Yassiry, Mustafa M.; Domarkas, Juozas; Lorch, Mark; Pickles, Martin; Gibbs, Peter; Tripier, Raphaël; Cawthorne, Christopher; Archibald, Stephen J.

    2015-09-01

    The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging.The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no

  3. Preparation and Bioavailability Analysis of Ferrous Bis Alanine Chelate as a New Micronutrient for Treatment of Iron Deficiency Anemia

    Science.gov (United States)

    Zargaran, Marzieh; Saadat, Ebrahim; Dinarvand, Rassoul; Sharifzadeh, Mohammad; Dorkoosh, Farid

    2016-01-01

    Purpose: One of the most nutritional disorders around the world is iron deficiency. A novel iron compound was synthesized by chelating ferrous ions with alanine for prevention and treatment of iron deficiency anemia. Methods: The newly synthesized compound was characterized both qualitatively and quantitatively by Fourier Transform Infrared (FT-IR) spectroscopy. The bioavailability of newly synthesized iron micronutrient was evaluated in four groups of Wistar rats. The group I was a negative control group and the other three groups received three different iron formulations. After 14 days, the blood samples were taken and analyzed accordingly. Results: Calculations showed that more than 91.8% of iron was incorporated in the chelate formulation. In vivo studies showed that serum iron, total iron binding capacity and hemoglobin concentrations were significantly increased in group IV, which received ferrous bis alanine chelate compared with the negative control group (p<0.05) and also group II, which received ferrous sulfate.7H2O (p<0.05). It indicates that the new formulation considerably improves the blood iron status compared with the conventional iron compounds. There were no significant differences (p<0.05) in the serum iron between group IV and group III, which received ferrous bis glycine. Conclusion: The results showed better bioavailability of ferrous bis alanine as a new micronutrient for treatment of iron deficiency anemia in comparison with ferrous sulfate. Ferrous bis alanine could be considered as a suitable supplement for prevention and treatment of iron deficiency anemia.

  4. Novel "hybrid" iron chelators derived from aroylhydrazones and thiosemicarbazones demonstrate selective antiproliferative activity against tumor cells.

    Science.gov (United States)

    Lovejoy, David B; Richardson, Des R

    2002-07-15

    We previously demonstrated that 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) and other aroylhydrazone chelators possess potent antineoplastic activity because of their ability to bind iron (Fe). From these studies, we identified structural components of the hydrazones that provide antineoplastic activity, namely the salicylaldehyde and 2-hydroxy-1-naphthylaldehyde moieties. A related group of chelators known as the thiosemicarbazones also show pronounced antitumor activity because of their ability to inhibit ribonucleotide reductase. Considering this, we designed a new series of "hybrid ligands" by condensation of the aldehydes described above with a range of thiosemicarbazides. The parent compound of these ligands is 2-hydroxy-1-naphthylaldehyde thiosemicarbazone (NT). Of 8 NT analogues, 3 chelators, namely NT, N4mT (2-hydroxy-1-naphthylaldehyde-4-methyl-3-thiosemicarbazone), and N44mT (2-hydroxy-1-naphthylaldehyde-4,4-dimethyl-3-thiosemicarbazone), showed high antiproliferative activity against SK-N-MC neuroepithelioma cells (50% inhibitory concentration [IC(50)] = 0.5-1.5 microM). Indeed, their activity was significantly (P <.0001) greater than that of desferrioxamine (DFO) (IC(50) = 22 microM). We demonstrate that 311, a 311 analogue (311m), and several NT-series chelators have significantly (P <.001) greater antiproliferative activity against tumor cells than against a range of normal cell types. For example, the IC(50) values of NT and N4mT in SK-N-MC neuroepithelioma cells were 0.5 microM, whereas for fibroblasts the IC(50) values were greater than 25 microM. Further, the effect of one of the most potent chelators (311m) on preventing the growth of bone marrow stem cell cultures was far less than that of doxorubicin and similar to that of cisplatin. These studies support the further development of these chelators as antiproliferative agents. PMID:12091363

  5. Comparative study of antioxidant, metal chelating and antiglycation activities of Momordica charantia flesh and pulp fractions.

    Science.gov (United States)

    Ghous, Tahseen; Aziz, Nouman; Mehmood, Zahid; Andleeb, Saiqa

    2015-07-01

    Momordica charantia is commonly used as a vegetable and folk medicine in most parts of South Asia. This study aims to determine and compare the antioxidant, metal chelating and antiglycation activities of aqueous extracts of M. charantia fruit flesh (MCF) and fruit pulp (MCP) fractions. Our results show that MCP has pronounced DPPH and ABTS radical scavenging potential compared to MCF. In the antiglycation assay both fractions illustrated considerable inhibitory activities against the formation of AGEs induced by glucose with an efficacy of 75 and 67% with 150 μl of MCP and MCF extracts respectively, almost equal to 0.3mM amino guanidine. Results for metal catalysed protein fragmentation and autoxidative and glycoxidation assays demonstrate that MCF and MCP inhibited metal catalysed protein fragmentation. The percentage of relative standard deviation for three replicate measurements of 150 μl of MCF and MCP was < 3.0% for antiglycation. The antioxidant assays with regression values of MCP (0.981 and 0.991) and MCF (0.967 and 0.999) were also recorded. We conclude that both extracts possess high antioxidant and antiglycation activities and are equally good sources of antioxidant and antiglycating agents. PMID:26142512

  6. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions.

    Science.gov (United States)

    Burke, Benjamin P; Baghdadi, Neazar; Kownacka, Alicja E; Nigam, Shubhanchi; Clemente, Gonçalo S; Al-Yassiry, Mustafa M; Domarkas, Juozas; Lorch, Mark; Pickles, Martin; Gibbs, Peter; Tripier, Raphaël; Cawthorne, Christopher; Archibald, Stephen J

    2015-09-28

    The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging. PMID:26292197

  7. Reduction in labile plasma iron during treatment with deferasirox, a once-daily oral iron chelator, in heavily iron-overloaded patients with β-thalassaemia

    OpenAIRE

    Daar, Shahina; Pathare, Anil; Nick, Hanspeter; Kriemler-Krahn, Ulrike; Hmissi, Abdel; Habr, Dany; Taher, Ali

    2009-01-01

    This subgroup analysis evaluated the effect of once-daily oral deferasirox on labile plasma iron (LPI) levels in patients from the prospective, 1-yr, multicentre ESCALATOR study. Mean baseline liver iron concentration and median serum ferritin levels were 28.6 ± 10.3 mg Fe/g dry weight and 6334 ng/mL respectively, indicating high iron burden despite prior chelation therapy. Baseline LPI levels (0.98 ± 0.82 μmol/L) decreased significantly to 0.12 ± 0.16 μmol/L, 2 h after first deferasirox dose...

  8. CARDIAC FUNCTION AND IRON CHELATION IN THALASSEMIA MAJOR AND INTERMEDIA: A REVIEW OF THE UNDERLYING PATHOPHYSIOLOGY AND APPROACH TO CHELATION MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Athanasios Aessopos

    2009-07-01

    Full Text Available Heart disease is the leading cause of mortality and one of the main causes of morbidity in beta-thalassemia. Patients with homozygous thalassemia may have either a severe phenotype which is usually transfusion dependent or a milder form that is thalassemia intermedia.  The two main factors that determine cardiac disease in homozygous β thalassemia are the high output state that results from chronic tissue hypoxia, hypoxia-induced compensatory reactions and iron overload.  The high output state playing a major role in thalassaemia intermedia and the iron load being more significant in the major form. Arrhythmias, vascular involvement that leads to an increased pulmonary vascular resistance and an increased systemic vascular stiffness and valvular abnormalities also contribute to the cardiac dysfunction in varying degrees according to the severity of the phenotype.  Endocrine abnormalities, infections, renal function and medications can also play a role in the overall cardiac function.  For thalassaemia major, regular and adequate blood transfusions and iron chelation therapy are the mainstays of management. The approach to thalassaemia intermedia, today, is aimed at monitoring for complications and initiating, timely, regular transfusions and/or iron chelation therapy.  Once the patients are on transfusions, then they should be managed in the same way as the thalassaemia major patients.  If cardiac manifestations of dysfunction are present in either form of thalassaemia, high pre transfusion Hb levels need to be maintained in order to reduce cardiac output and appropriate intensive chelation therapy needs to be instituted.  In general recommendations on chelation, today, are usually made according to the Cardiac Magnetic Resonance findings, if available.  With the advances in the latter technology and the ability to tailor chelation therapy according to the MRI findings as well as the availability of three iron chelators, together with

  9. Effects of Iron Chelators on the Formation and Development of Aspergillus fumigatus Biofilm.

    Science.gov (United States)

    Nazik, Hasan; Penner, John C; Ferreira, Jose A; Haagensen, Janus A J; Cohen, Kevin; Spormann, Alfred M; Martinez, Marife; Chen, Vicky; Hsu, Joe L; Clemons, Karl V; Stevens, David A

    2015-10-01

    Iron acquisition is crucial for the growth of Aspergillus fumigatus. A. fumigatus biofilm formation occurs in vitro and in vivo and is associated with physiological changes. In this study, we assessed the effects of Fe chelators on biofilm formation and development. Deferiprone (DFP), deferasirox (DFS), and deferoxamine (DFM) were tested for MIC against a reference isolate via a broth macrodilution method. The metabolic effects (assessed by XTT [2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt]) on biofilm formation by conidia were studied upon exposure to DFP, DFM, DFP plus FeCl3, or FeCl3 alone. A preformed biofilm was exposed to DFP with or without FeCl3. The DFP and DFS MIC50 against planktonic A. fumigatus was 1,250 μM, and XTT gave the same result. DFM showed no planktonic inhibition at concentrations of ≤2,500 μM. By XTT testing, DFM concentrations of biofilms forming in A. fumigatus or preformed biofilms (P biofilm formation (P Biofilm formation with 625 μM DFP plus any concentration of FeCl3 was lower than that in the controls (P biofilms, DFP in the range of ≥625 to 1,250 μM was inhibitory compared to the controls (P biofilm formation (P biofilm increased with 2,500 μM FeCl3 only (P biofilms of A. fumigatus clinical isolates to DFP were noted. In conclusion, iron stimulates biofilm formation and preformed biofilms. Chelators can inhibit or enhance biofilms. Chelation may be a potential therapy for A. fumigatus, but we show here that chelators must be chosen carefully. Individual isolate susceptibility assessments may be needed.

  10. Iron (II)-chelating activity of buffalo αS-casein hydrolysed by corolase PP, alcalase and flavourzyme

    OpenAIRE

    Jaiswal, Arvind; Bajaj, Rajesh; Mann, Bimlesh; Lata, Kiran

    2014-01-01

    Iron is a vital substance for human health which participates in many biochemical reactions. It also act as initiator for many harmful oxidative process. Buffalo αS-casein enriched fraction (80 %) was hydrolysed independently by corolase PP (H1), alcalase (H2), flavourzyme (H3) and sequentially by alcalase-flavourzyme (H4). After ultrafiltration (10 and 3 kDa) hydrolysates were analysed for their iron chelation activity using ferrozine. For H1 group of hydrolysates highest iron (II)-chelation...

  11. [Iron chelation therapy and its influence on the alleviation of EPO resistance in MDS patients].

    Science.gov (United States)

    Zhang, Yao; Xiao, Chao; Gu, Shu-Cheng; Chang, Chun-Kang

    2014-08-01

    This study was aimed to investigate the changes of erythropoietin (EPO), hemoglobin(Hb) and recombinant EPO (rEPO) levels in MDS patients receiving iron chelation therapy, and to explore the relationship between EPO and serum ferritin(SF). A total of 172 MDS patients and 30 healthy controls were studied. The levels of SF, EPO, serum iron (SI), total iron binding capacity (TIBC), C-reaction protein (CRP) and Hb were measured respectively, the level of SF was adjusted according to the changes of CRP. Among them, there were 34 cases of low-risk (SF>1 000 mg/L) receiving deferoxamine therapy, whose changes of SF, EPO, SI, TIBC, Hb levels were detected and compared before and after treatment. Besides, the difference in the incidence of EPO resistance in iron overload group and non-iron overload group was assessed before and after therapy, and 58 cases of low-risk and EPO<1 000 U/L MDS patients were given rEPO therapy. The results showed that the level of EPO in non-iron overload group was higher than that in the normal control group (997.44 ± 473.48 vs 467.27 ± 238.49, P < 0.05). Obviously, the level of EPO in iron overload group was higher than that in non-iron overload group and control group (3257.59 ± 697.19 vs 997.44 ± 473.48, P = 0.012, 3257.59 ± 697.19 vs 467.27 ± 238.49, P = 0.002). Otherwise, the incidence of EPO resistance in iron overload group was higher than that in non-iron overload group (18/35 vs 2/23, P = 0.001), and the level of EPO and SF was positively related to each other in iron overload group (r = 0.310,P = 0.036). After receiving iron chelation therapy, the levels of SF, SI, TIBC and EPO in iron overload group were significantly lower than that before therapy (3942.38 ± 641.82 vs 2266.35 ± 367.31, P = 0.028;48.61 ± 10.65 vs 28.52 ± 12.61, P = 0.034;59.84 ± 12.62 vs 33.76 ± 15.43, P = 0.045;3808.01 ± 750.22 vs 1954.78 ± 473.18, P = 0.042). Moreover, the level of Hb increased (35 ± 18 vs 57 ± 21, P = 0.046) and the EPO resistance

  12. Modulatory effect of iron chelators on adenosine deaminase activity and gene expression in Trichomonas vaginalis.

    Science.gov (United States)

    Primon-Barros, Muriel; Rigo, Graziela Vargas; Frasson, Amanda Piccoli; Santos, Odelta dos; Smiderle, Lisiane; Almeida, Silvana; Macedo, Alexandre José; Tasca, Tiana

    2015-11-01

    Trichomonas vaginalis is a flagellate protozoan that parasitises the urogenital human tract and causes trichomoniasis. During the infection, the acquisition of nutrients, such as iron and purine and pyrimidine nucleosides, is essential for the survival of the parasite. The enzymes for purinergic signalling, including adenosine deaminase (ADA), which degrades adenosine to inosine, have been characterised in T. vaginalis. In the evaluation of the ADA profile in different T. vaginalis isolates treated with different iron sources or with limited iron availability, a decrease in activity and an increase in ADA gene expression after iron limitation by 2,2-bipyridyl and ferrozine chelators were observed. This supported the hypothesis that iron can modulate the activity of the enzymes involved in purinergic signalling. Under bovine serum limitation conditions, no significant differences were observed. The results obtained in this study allow for the assessment of important aspects of ADA and contribute to a better understanding of the purinergic system in T. vaginalis and the role of iron in establishing infection and parasite survival.

  13. Curcumin Inhibits Growth of Saccharomyces cerevisiae through Iron Chelation ▿ ††

    Science.gov (United States)

    Minear, Steven; O'Donnell, Allyson F.; Ballew, Anna; Giaever, Guri; Nislow, Corey; Stearns, Tim; Cyert, Martha S.

    2011-01-01

    Curcumin, a polyphenol derived from turmeric, is an ancient therapeutic used in India for centuries to treat a wide array of ailments. Interest in curcumin has increased recently, with ongoing clinical trials exploring curcumin as an anticancer therapy and as a protectant against neurodegenerative diseases. In vitro, curcumin chelates metal ions. However, although diverse physiological effects have been documented for this compound, curcumin's mechanism of action on mammalian cells remains unclear. This study uses yeast as a model eukaryotic system to dissect the biological activity of curcumin. We found that yeast mutants lacking genes required for iron and copper homeostasis are hypersensitive to curcumin and that iron supplementation rescues this sensitivity. Curcumin penetrates yeast cells, concentrates in the endoplasmic reticulum (ER) membranes, and reduces the intracellular iron pool. Curcumin-treated, iron-starved cultures are enriched in unbudded cells, suggesting that the G1 phase of the cell cycle is lengthened. A delay in cell cycle progression could, in part, explain the antitumorigenic properties associated with curcumin. We also demonstrate that curcumin causes a growth lag in cultured human cells that is remediated by the addition of exogenous iron. These findings suggest that curcumin-induced iron starvation is conserved from yeast to humans and underlies curcumin's medicinal properties. PMID:21908599

  14. Wild Edible Fruit of Prunus nepalensis Ser. (Steud), a Potential Source of Antioxidants, Ameliorates Iron Overload-Induced Hepatotoxicity and Liver Fibrosis in Mice.

    Science.gov (United States)

    Chaudhuri, Dipankar; Ghate, Nikhil Baban; Panja, Sourav; Das, Abhishek; Mandal, Nripendranath

    2015-01-01

    The antioxidant and restoration potentials of hepatic injury by Prunus nepalensis Ser. (Steud), a wild fruit plant from the Northeastern region of India, were investigated. The fruit extract (PNME) exhibited excellent antioxidant and reducing properties and also scavenged the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (IC50 = 30.92 ± 0.40 μg/ml). PNME demonstrated promising scavenging potency, as assessed by the scavenging of different reactive oxygen and nitrogen species. Moreover, the extract revealed an exceptional iron chelation capacity with an IC50 of 25.64 ± 0.60 μg/ml. The extract induced significant improvement of hepatic injury and liver fibrosis against iron overload induced hepatotoxicity in mice in a dose-dependent manner, and this effect was supported by different histopathological studies. The phytochemical constitutions and their identification by HPLC confirmed the presence of purpurin, tannic acid, methyl gallate, reserpine, gallic acid, ascorbic acid, catechin and rutin. The identified compounds were investigated for their individual radical scavenging and iron chelation activity; some compounds exhibited excellent radical scavenging and iron chelation properties, but most were toxic towards normal cells (WI-38). On the other hand, crude PNME was found to be completely nontoxic to normal cells, suggesting its feasibility as a safe oral drug. The above study suggests that different phytochemicals in PNME contributed to its free radical scavenging and iron chelation activity; however, further studies are required to determine the pathway in which PNME acts to treat iron-overload diseases.

  15. Chemical, physical, and sensory characteristics of mozzarella cheese fortified using protein-chelated iron or ferric chloride.

    Science.gov (United States)

    Rice, W H; McMahon, D J

    1998-02-01

    Mozzarella cheese containing 25 and 50 mg of iron/kg of cheese was manufactured from milk that had been fortified with casein-chelated iron, whey protein-chelated iron, or FeCl3. Chemical, physical, and sensory characteristics were compared with those of a control cheese. Physical properties were assessed by testing melting, apparent viscosity, and browning of heated cheese. Cheeses were evaluated by trained panelists for the presence of metallic flavors, oxidized flavors, and other undesirable flavors. Addition of 25 mg iron/kg of cheese had no effects on the physical properties of Mozzarella cheese. Apparent viscosity of cheese fortified with 50 mg of iron/kg of cheese tended to be slightly higher than the control cheese, although this difference was not statistically significant at all storage times. Cook color was not affected by iron fortification. No increase in chemical oxidation (measured using thiobarbituric acid assay) was observed between the control and iron-fortified cheeses. Slight but statistically significant increases in metallic flavors, oxidized flavors, and off-flavors in the iron-fortified cheese were observed by the trained sensory panel, but the flavor defects were of very low intensity. For metallic flavors, oxidized flavors, and off-flavors, the control cheese scored 1.5, 1.5, and 1.3, respectively; the iron-fortified cheese scored 2.1, 2.0, and 1.6 based on a nine-point scale (where 1 = not perceptible to 3 = slightly perceptible). Sensory scores for iron-fortified cheese made using casein-chelated iron or whey protein-chelated iron was not significantly different from those of cheese made using ferric chloride. When used on pizza, consumer panels rated the iron-fortified cheeses as comparable with the control cheese. PMID:9532487

  16. Mutational reconstructed ferric chelate reductase confers enhanced tolerance in rice to iron deficiency in calcareous soil

    OpenAIRE

    Ishimaru, Yasuhiro; Kim, Suyeon; Tsukamoto, Takashi; Oki, Hiroyuki; Kobayashi, Takanori; Watanabe, Satoshi; Matsuhashi, Shinpei; Takahashi, Michiko; Nakanishi, Hiromi; Mori, Satoshi; Naoko K. Nishizawa

    2007-01-01

    Iron (Fe) deficiency is a worldwide agricultural problem on calcareous soils with low-Fe availability due to high soil pH. Rice plants use a well documented phytosiderophore-based system (Strategy II) to take up Fe from the soil and also possess a direct Fe2+ transport system. Rice plants are extremely susceptible to low-Fe supply, however, because of low phytosiderophore secretion and low Fe3+ reduction activity. A yeast Fe3+ chelate-reductase gene refre1/372, selected for better performance...

  17. Rapid Regeneration of Chelated Iron Desulfurization Solution Using Electrochemical Reactor with Rotating Cylindrical Electrodes

    Institute of Scientific and Technical Information of China (English)

    于永; 刘有智; 祁贵生

    2014-01-01

    A new electrochemical reactor with rotating cylindrical electrodes was designed and used to increase the regeneration efficiency of chelated iron desulfurization solution. The influence of operating parameters, such as the rotation speed of electrode, voltage, and inlet air and liquid flow rates, on the regeneration rate was investigated. Compared with the traditional tank-type reactor, the regeneration rate with the new electrochemical reactor was in-creased significantly. Under the optimum conditions, the regeneration rate was increased from 45.3% to 84.8%. Experimental results of continuous operation indicated that the new electrochemical regeneration method had some merits including higher regeneration efficiency, smaller equipment size and good stability in operation.

  18. Iron Chelation

    Science.gov (United States)

    ... information, it does not guarantee the accuracy or currency of this information. ... makes it possible to meet patients' needs, hold impactful conferences, develop fresh education programs and fund research for the cures, along ...

  19. Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial

    DEFF Research Database (Denmark)

    Lee, Jong Wook; Yoon, Sung-Soo; Shen, Zhi Xiang;

    2010-01-01

    The prospective 1-year Evaluation of Patients' Iron Chelation with Exjade (EPIC) study enrolled a large cohort of 116 patients with aplastic anemia; the present analyses evaluated the efficacy and safety of deferasirox in this patient population. After 1 year, median serum ferritin decreased...... significantly from 3254 ng/mL at baseline to 1854 ng/mL (P chelation-naive (3229-1520 ng/mL; P chelated (3263-2585 ng/mL; P = .21, last-observation-carried-forward analysis) patients and were reflective of dose...

  20. The Pseudomonas aeruginosa extracellular secondary metabolite, Paerucumarin, chelates iron and is not localized to extracellular membrane vesicles.

    Science.gov (United States)

    Qaisar, Uzma; Kruczek, Cassandra J; Azeem, Muhammed; Javaid, Nasir; Colmer-Hamood, Jane A; Hamood, Abdul N

    2016-08-01

    Proteins encoded by the Pseudomonas aeruginosa pvcA-D operon synthesize a novel isonitrile functionalized cumarin termed paerucumarin. The pvcA-D operon enhances the expression of the P. aeruginosa fimbrial chaperone/usher pathway (cup) genes and this effect is mediated through paerucumarin. Whether pvcA-D and/or paerucumarin affect the expression of other P. aeruginosa genes is not known. In this study, we examined the effect of a mutation in pvcA-D operon the global transcriptome of the P. aeruginosa strain PAO1-UW. The mutation reduced the expression of several ironcontrolled genes including pvdS, which is essential for the expression of the pyoverdine genes. Additional transcriptional studies showed that the pvcA-D operon is not regulated by iron. Exogenously added paerucumarin enhanced pyoverdine production and pvdS expression in PAO1-UW. Iron-chelation experiments revealed that purified paerucumarin chelates iron. However, exogenously added paerucumarin significantly reduced the growth of a P. aeruginosa mutant defective in pyoverdine and pyochelin production. In contrast to other secondary metabolite, Pseudomonas quinolone signal (PQS), paerucumarin is not localized to the P. aeruginosa membrane vesicles. These results suggest that paerucumarin enhances the expression of iron-controlled genes by chelating iron within the P. aeruginosa extracellular environment. Although paerucumarin chelates iron, it does not function as a siderophore. Unlike PQS, paerucumarin is not associated with the P. aeruginosa cell envelope. PMID:27480638

  1. Chelating, antioxidant and hypoglycaemic potential of Muscari comosum (L.) Mill. bulb extracts.

    Science.gov (United States)

    Loizzo, Monica R; Tundis, Rosa; Menichini, Federica; Pugliese, Alessandro; Bonesi, Marco; Solimene, Umberto; Menichini, Francesco

    2010-12-01

    The metal chelating activity, antioxidant properties and the effect on carbohydrate-hydrolysing enzyme inhibition of Muscari comosum extracts have been investigated. M. comosum bulbs contain a total amount of the phenols with a value of 56.6 mg chlorogenic acid equivalent per gram of extract and a flavonoid content of 23.4 mg quercetin equivalent per gram of extract. In order to evaluate the non-polar constituents, n-hexane extract was obtained. Gas chromatography-mass spectrometry analysis revealed the presence of fatty acids and ethyl esters as major constituents, with different aldehydes and alkanes as minor components. Ethanolic extract had the highest ferric-reducing ability power (66.7 μM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC₅₀) value of 40.9 μg/ml. Moreover, this extract exhibited a good hypoglycaemic activity with IC₅₀ values of 81.3 and 112.8 μg/ml for α-amylase and α-glucosidase, respectively. In conclusion, M. comosum bulbs show promising antioxidant and hypoglycaemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from a functional point of view and for the revalorization of this ancient non-cultivated vegetable of Mediterranean traditional gastronomy.

  2. Chelating, antioxidant and hypoglycaemic potential of Muscari comosum (L.) Mill. bulb extracts.

    Science.gov (United States)

    Loizzo, Monica R; Tundis, Rosa; Menichini, Federica; Pugliese, Alessandro; Bonesi, Marco; Solimene, Umberto; Menichini, Francesco

    2010-12-01

    The metal chelating activity, antioxidant properties and the effect on carbohydrate-hydrolysing enzyme inhibition of Muscari comosum extracts have been investigated. M. comosum bulbs contain a total amount of the phenols with a value of 56.6 mg chlorogenic acid equivalent per gram of extract and a flavonoid content of 23.4 mg quercetin equivalent per gram of extract. In order to evaluate the non-polar constituents, n-hexane extract was obtained. Gas chromatography-mass spectrometry analysis revealed the presence of fatty acids and ethyl esters as major constituents, with different aldehydes and alkanes as minor components. Ethanolic extract had the highest ferric-reducing ability power (66.7 μM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC₅₀) value of 40.9 μg/ml. Moreover, this extract exhibited a good hypoglycaemic activity with IC₅₀ values of 81.3 and 112.8 μg/ml for α-amylase and α-glucosidase, respectively. In conclusion, M. comosum bulbs show promising antioxidant and hypoglycaemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from a functional point of view and for the revalorization of this ancient non-cultivated vegetable of Mediterranean traditional gastronomy. PMID:20465433

  3. New hydroxypyridinone iron-chelators as potential anti-neurodegenerative drugs.

    Science.gov (United States)

    Arduino, Daniela; Silva, Daniel; Cardoso, Sandra M; Chaves, Silvia; Oliveira, Catarina R; Santos, M Amelia

    2008-05-01

    The neuroprotective action of a set of new hydroxypyridinone-based (3,4-HP) compounds (A, B and C), which are iron chelators extra-functionalized with a propargylamino group for potential MAO-B inhibition, was evaluated after cell treatment with MPP+ (an in vivo inducer of parkinsonism) and Abeta(1-40) and/or Abeta(1-42) peptides. Our results show that all these compounds improved cell viability in cells treated with MPP+ and Abeta(1-40) peptide or Abeta(1-42) peptide. In order to evaluate the cellular mechanisms underlying the activity of these compounds, we studied their protective role in caspase activation. All compounds tested were able to prevent MPP+ and Brefeldin A induced caspase-2 activation. They also showed quite effective in the inhibition of caspase-4 and caspase-3 activity, an effector caspase in the apoptotic process. Finally, detection of apoptotic-like cell death after cell exposure to MPP+ was also performed by TUNEL assay. Our results demonstrated that all tested compounds prevented DNA fragmentation by decreasing TUNEL positive cells. A, B and C were more effective than DFP (a 3,4-HP iron-chelating agent in clinical use) in MPP+ induced cell death. Therefore, these results evidenced a neuroprotective and antiapoptotic role for the compounds studied.

  4. High-performance liquid chromatography method for ferric iron chelators using a post-column reaction with Calcein Blue.

    Science.gov (United States)

    Ariga, Tomoko; Ito, Kyoko; Imura, Yuki; Yoshimura, Etsuro

    2015-03-15

    Iron (Fe) is an essential element for higher plants, which take it up from the soil at the root surface and transport it to shoots through the xylem. Fe(III) chelators, such as organic acids and phytosiderophores, play important roles in the acquisition and transportation of Fe(III). Therefore, a selective and sensitive method for analyzing Fe(III) chelators is required to study the many Fe-related physiological mechanisms in plants. A novel analytical approach employing a high-performance liquid chromatography post-column method with fluorescence detection was developed to separate and detect Fe(III) chelators. This method takes advantage of the quenching of the fluorescence of Calcein Blue (CB) that occurs with the formation of an Fe(III)-CB complex and the dequenching that occurs with the release of CB as a result of competition for Fe(III) between CB and an Fe(III) chelator. This simple experimental method does not require complicated pretreatments and can selectively detect Fe(III) chelators according to their Fe(III)-chelating ability. The detection limit for citric acid using this method was 72pmol. Furthermore, this method can also detect unknown Fe(III) chelators that exhibit a high affinity for Fe(III). The method was evaluated with xylem sap of barley, which was shown to contain several Fe(III) chelators. PMID:25658515

  5. Expanding horizons in iron chelation and the treatment of cancer: role of iron in the regulation of ER stress and the epithelial-mesenchymal transition.

    Science.gov (United States)

    Lane, Darius J R; Mills, Thomas M; Shafie, Nurul H; Merlot, Angelica M; Saleh Moussa, Rayan; Kalinowski, Danuta S; Kovacevic, Zaklina; Richardson, Des R

    2014-04-01

    Cancer is a major public health issue and, despite recent advances, effective clinical management remains elusive due to intra-tumoural heterogeneity and therapeutic resistance. Iron is a trace element integral to a multitude of metabolic processes, including DNA synthesis and energy transduction. Due to their generally heightened proliferative potential, cancer cells have a greater metabolic demand for iron than normal cells. As such, iron metabolism represents an important "Achilles' heel" for cancer that can be targeted by ligands that bind and sequester intracellular iron. Indeed, novel thiosemicarbazone chelators that act by a "double punch" mechanism to both bind intracellular iron and promote redox cycling reactions demonstrate marked potency and selectivity in vitro and in vivo against a range of tumours. The general mechanisms by which iron chelators selectively target tumour cells through the sequestration of intracellular iron fall into the following categories: (1) inhibition of cellular iron uptake/promotion of iron mobilisation; (2) inhibition of ribonucleotide reductase, the rate-limiting, iron-containing enzyme for DNA synthesis; (3) induction of cell cycle arrest; (4) promotion of localised and cytotoxic reactive oxygen species production by copper and iron complexes of thiosemicarbazones (e.g., Triapine(®) and Dp44mT); and (5) induction of metastasis and tumour suppressors (e.g., NDRG1 and p53, respectively). Emerging evidence indicates that chelators can further undermine the cancer phenotype via inhibiting the epithelial-mesenchymal transition that is critical for metastasis and by modulating ER stress. This review explores the "expanding horizons" for iron chelators in selectively targeting cancer cells. PMID:24472573

  6. Anti-Plasmodial Activity of Aroylhydrazone and Thiosemicarbazone Iron Chelators: Effect on Erythrocyte Membrane Integrity, Parasite Development and the Intracellular Labile Iron Pool

    OpenAIRE

    Walcourt, Asikiya; Kurantsin-Mills, Joseph; Kwagyan, John; Adenuga, Babafemi B.; Kalinowski, Danuta S.; Lovejoy, David B.; Lane, Darius J.R.; Richardson, Des R.

    2013-01-01

    Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-re...

  7. Selection of Chelated Fe (III)/Fe (II) Catalytic Oxidation Agents for Desulfurization Based on Iron Complexation Method

    Institute of Scientific and Technical Information of China (English)

    Luo Ying; Liu Youzhi; Qi Guisheng; Guo Huidong; Zhu Zhengfeng

    2014-01-01

    Optimization of factors inlfuencing the experiments on reactions involving 8 different chelating agents and sol-uble Fe (III)/Fe (II) salts was carried out to yield chelated iron complexes. A combination of optimized inlfuencing factors has resulted in a Fe chelating capacity of the iron-based desulfurization solution to be equal to 6.83—13.56 g/L at a redox potential of 0.185—0.3. The desulfurization performance of Fe (III)/Fe (II) chelating agents was investigated on a simulated sulfur-containing industrial gas composed of H2S and N2 in a cross-lfow rotating packed bed. Test results have revealed that the proposed iron-based desulfurization solution showed a sulfur removal efifciency of over 99%along with a Fe chelating capacity exceeding 1.35 g/L. This desulfurization technology which has practical application prospect is currently in the phase of commercial scale-up study.

  8. Iron Hydride Detection and Intramolecular Hydride Transfer in a Synthetic Model of Mono-Iron Hydrogenase with a CNS Chelate.

    Science.gov (United States)

    Durgaprasad, Gummadi; Xie, Zhu-Lin; Rose, Michael J

    2016-01-19

    We report the identification and reactivity of an iron hydride species in a synthetic model complex of monoiron hydrogenase. The hydride complex is derived from a phosphine-free CNS chelate that includes a Fe-C(NH)(═O) bond (carbamoyl) as a mimic of the active site iron acyl. The reaction of [((O═)C(HN)N(py)S(Me))Fe(CO)2(Br)] (1) with NaHBEt3 generates the iron hydride intermediate [((O═)C(HN)N(py)S(Me))Fe(H)(CO)2] (2; δFe-H = -5.08 ppm). Above -40 °C, the hydride species extrudes CH3S(-) via intramolecular hydride transfer, which is stoichiometrically trapped in the structurally characterized dimer μ2-(CH3S)2-[((O═)C(HN)N(Ph))Fe(CO)2]2 (3). Alternately, when activated by base ((t)BuOK), 1 undergoes desulfurization to form a cyclometalated species, [((O═)C(NH)NC(Ph))Fe(CO)2] (5); derivatization of 5 with PPh3 affords the structurally characterized species [((O═)C(NH)NC)Fe(CO)(PPh3)2] (6), indicating complex 6 as the common intermediate along each pathway of desulfurization.

  9. Effect of Systemic Iron Overload and a Chelation Therapy in a Mouse Model of the Neurodegenerative Disease Hereditary Ferritinopathy

    Science.gov (United States)

    Li, Wei; Goodwin, Charles B.; Richine, Briana; Acton, Anthony; Chan, Rebecca J.; Peacock, Munro; Muhoberac, Barry B.; Ghetti, Bernardino; Vidal, Ruben

    2016-01-01

    Mutations in the ferritin light chain (FTL) gene cause the neurodegenerative disease neuroferritinopathy or hereditary ferritinopathy (HF). HF is characterized by a severe movement disorder and by the presence of nuclear and cytoplasmic iron-containing ferritin inclusion bodies (IBs) in glia and neurons throughout the central nervous system (CNS) and in tissues of multiple organ systems. Herein, using primary mouse embryonic fibroblasts from a mouse model of HF, we show significant intracellular accumulation of ferritin and an increase in susceptibility to oxidative damage when cells are exposed to iron. Treatment of the cells with the iron chelator deferiprone (DFP) led to a significant improvement in cell viability and a decrease in iron content. In vivo, iron overload and DFP treatment of the mouse model had remarkable effects on systemic iron homeostasis and ferritin deposition, without significantly affecting CNS pathology. Our study highlights the role of iron in modulating ferritin aggregation in vivo in the disease HF. It also puts emphasis on the potential usefulness of a therapy based on chelators that can target the CNS to remove and redistribute iron and to resolubilize or prevent ferritin aggregation while maintaining normal systemic iron stores. PMID:27574973

  10. Effect of Systemic Iron Overload and a Chelation Therapy in a Mouse Model of the Neurodegenerative Disease Hereditary Ferritinopathy.

    Science.gov (United States)

    Garringer, Holly J; Irimia, Jose M; Li, Wei; Goodwin, Charles B; Richine, Briana; Acton, Anthony; Chan, Rebecca J; Peacock, Munro; Muhoberac, Barry B; Ghetti, Bernardino; Vidal, Ruben

    2016-01-01

    Mutations in the ferritin light chain (FTL) gene cause the neurodegenerative disease neuroferritinopathy or hereditary ferritinopathy (HF). HF is characterized by a severe movement disorder and by the presence of nuclear and cytoplasmic iron-containing ferritin inclusion bodies (IBs) in glia and neurons throughout the central nervous system (CNS) and in tissues of multiple organ systems. Herein, using primary mouse embryonic fibroblasts from a mouse model of HF, we show significant intracellular accumulation of ferritin and an increase in susceptibility to oxidative damage when cells are exposed to iron. Treatment of the cells with the iron chelator deferiprone (DFP) led to a significant improvement in cell viability and a decrease in iron content. In vivo, iron overload and DFP treatment of the mouse model had remarkable effects on systemic iron homeostasis and ferritin deposition, without significantly affecting CNS pathology. Our study highlights the role of iron in modulating ferritin aggregation in vivo in the disease HF. It also puts emphasis on the potential usefulness of a therapy based on chelators that can target the CNS to remove and redistribute iron and to resolubilize or prevent ferritin aggregation while maintaining normal systemic iron stores. PMID:27574973

  11. Effects of intracellular chelatable iron and oxidative stress on transcription of classical cellular glutathione peroxidase gene in murine erythroleukemia cells

    International Nuclear Information System (INIS)

    The effect of intracellular chelatable iron levels and of oxidative stress on nuclear classical cellular glutathione peroxidase (GSHPx-1) RNA nascent chain elongation (run-on transcription) and on the stability of cytoplasmic GSHPx-1 mRNA was investigated in murine erythroleukemia (MEL) cells. The amount in the intracellular low molecular mass iron pool was changed by incubation of MEL cells transformed by Friend virus with iron donors or iron chelators. Transcription in vitro in isolated nuclei from treated cells showed that the treatment with chelators (desferrioxamine (DFO), pyridoxal isonicotinoyl hydrazone) decrease the rate of nuclear GSHPx-1 RNA nascent chain elongation in both un-induced and with 5 mmol hexamethylenebisacetamide to erythroid differentiation induced MEL cells. Iron donors (diferric transferrin,, Fe-PIH or their combination) and t-butyl hydroperoxide (t-BuOOH) had the opposite effect on GSHPx-1 gene transcription in run-on experiments. On the other hand, 50 μmol DFO or 2.5 μmol t-BuOOH did not change the stability of cytoplasmic GSHPx-1 mRNA in both un-induced and induced MEL cells treated with 5 μmol actinomycin D and with or without these agents for 9 h. These findings indicate that iron and oxidative stress play their role at the transcriptional level of GSHPx-1 gene expression. (author)

  12. Antioxidant and Metal Chelation-Based Therapies in the Treatment of Prion Disease.

    Science.gov (United States)

    Brazier, Marcus W; Wedd, Anthony G; Collins, Steven J

    2014-04-21

    Many neurodegenerative disorders involve the accumulation of multimeric assemblies and amyloid derived from misfolded conformers of constitutively expressed proteins. In addition, the brains of patients and experimental animals afflicted with prion disease display evidence of heightened oxidative stress and damage, as well as disturbances to transition metal homeostasis. Utilising a variety of disease model paradigms, many laboratories have demonstrated that copper can act as a cofactor in the antioxidant activity displayed by the prion protein while manganese has been implicated in the generation and stabilisation of disease-associated conformers. This and other evidence has led several groups to test dietary and chelation therapy-based regimens to manipulate brain metal concentrations in attempts to influence the progression of prion disease in experimental mice. Results have been inconsistent. This review examines published data on transition metal dyshomeostasis, free radical generation and subsequent oxidative damage in the pathogenesis of prion disease. It also comments on the efficacy of trialed therapeutics chosen to combat such deleterious changes.

  13. Antioxidant and Metal Chelation-Based Therapies in the Treatment of Prion Disease

    Directory of Open Access Journals (Sweden)

    Marcus W. Brazier

    2014-04-01

    Full Text Available Many neurodegenerative disorders involve the accumulation of multimeric assemblies and amyloid derived from misfolded conformers of constitutively expressed proteins. In addition, the brains of patients and experimental animals afflicted with prion disease display evidence of heightened oxidative stress and damage, as well as disturbances to transition metal homeostasis. Utilising a variety of disease model paradigms, many laboratories have demonstrated that copper can act as a cofactor in the antioxidant activity displayed by the prion protein while manganese has been implicated in the generation and stabilisation of disease-associated conformers. This and other evidence has led several groups to test dietary and chelation therapy-based regimens to manipulate brain metal concentrations in attempts to influence the progression of prion disease in experimental mice. Results have been inconsistent. This review examines published data on transition metal dyshomeostasis, free radical generation and subsequent oxidative damage in the pathogenesis of prion disease. It also comments on the efficacy of trialed therapeutics chosen to combat such deleterious changes.

  14. An Antioxidant Extract of the Insectivorous Plant Drosera burmannii Vahl. Alleviates Iron-Induced Oxidative Stress and Hepatic Injury in Mice.

    Science.gov (United States)

    Ghate, Nikhil Baban; Chaudhuri, Dipankar; Das, Abhishek; Panja, Sourav; Mandal, Nripendranath

    2015-01-01

    Free iron typically leads to the formation of excess free radicals, and additional iron deposition in the liver contributes to the oxidative pathologic processes of liver disease. Many pharmacological properties of the insectivorous plant Drosera burmannii Vahl. have been reported in previous studies; however, there is no evidence of its antioxidant or hepatoprotective potential against iron overload. The antioxidant activity of 70% methanolic extract of D. burmannii (DBME) was evaluated. DBME showed excellent DPPH, hydroxyl, hypochlorous, superoxide, singlet oxygen, nitric oxide, peroxynitrite radical and hydrogen peroxide scavenging activity. A substantial iron chelation (IC50 = 40.90 ± 0.31 μg/ml) and supercoiled DNA protection ([P]50 = 50.41 ± 0.55 μg) were observed. DBME also displayed excellent in vivo hepatoprotective activity in iron-overloaded Swiss albino mice compared to the standard desirox treatment. Administration of DBME significantly normalized serum enzyme levels and restored liver antioxidant enzymes levels. DBME lowered the raised levels of liver damage parameters, also reflected from the morphological analysis of the liver sections. DBME also reduced liver iron content by 115.90% which is also seen by Perls' staining. A phytochemical analysis of DBME confirms the presence of various phytoconstituents, including phenols, flavonoids, carbohydrates, tannins, alkaloids and ascorbic acid. Alkaloids, phenols and flavonoids were abundantly found in DBME. An HPLC analysis of DBME revealed the presence of purpurin, catechin, tannic acid, reserpine, methyl gallate and rutin. Purpurin, tannic acid, methyl gallate and rutin displayed excellent iron chelation but exhibited cytotoxicity toward normal (WI-38) cells; while DBME found to be non-toxic to the normal cells. These findings suggest that the constituents present in DBME contributed to its iron chelation activity. Additional studies are needed to determine if DBME can be used as a treatment for

  15. An Antioxidant Extract of the Insectivorous Plant Drosera burmannii Vahl. Alleviates Iron-Induced Oxidative Stress and Hepatic Injury in Mice.

    Directory of Open Access Journals (Sweden)

    Nikhil Baban Ghate

    Full Text Available Free iron typically leads to the formation of excess free radicals, and additional iron deposition in the liver contributes to the oxidative pathologic processes of liver disease. Many pharmacological properties of the insectivorous plant Drosera burmannii Vahl. have been reported in previous studies; however, there is no evidence of its antioxidant or hepatoprotective potential against iron overload. The antioxidant activity of 70% methanolic extract of D. burmannii (DBME was evaluated. DBME showed excellent DPPH, hydroxyl, hypochlorous, superoxide, singlet oxygen, nitric oxide, peroxynitrite radical and hydrogen peroxide scavenging activity. A substantial iron chelation (IC50 = 40.90 ± 0.31 μg/ml and supercoiled DNA protection ([P]50 = 50.41 ± 0.55 μg were observed. DBME also displayed excellent in vivo hepatoprotective activity in iron-overloaded Swiss albino mice compared to the standard desirox treatment. Administration of DBME significantly normalized serum enzyme levels and restored liver antioxidant enzymes levels. DBME lowered the raised levels of liver damage parameters, also reflected from the morphological analysis of the liver sections. DBME also reduced liver iron content by 115.90% which is also seen by Perls' staining. A phytochemical analysis of DBME confirms the presence of various phytoconstituents, including phenols, flavonoids, carbohydrates, tannins, alkaloids and ascorbic acid. Alkaloids, phenols and flavonoids were abundantly found in DBME. An HPLC analysis of DBME revealed the presence of purpurin, catechin, tannic acid, reserpine, methyl gallate and rutin. Purpurin, tannic acid, methyl gallate and rutin displayed excellent iron chelation but exhibited cytotoxicity toward normal (WI-38 cells; while DBME found to be non-toxic to the normal cells. These findings suggest that the constituents present in DBME contributed to its iron chelation activity. Additional studies are needed to determine if DBME can be used as a

  16. Bp44mT: an orally active iron chelator of the thiosemicarbazone class with potent anti-tumour efficacy

    Science.gov (United States)

    Yu, Y; Rahmanto, Y Suryo; Richardson, DR

    2012-01-01

    BACKGROUND AND PURPOSE Our previous studies demonstrated that a thiosemicarbazone iron chelator (di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone; Dp44mT) possesses potent and selective anti-cancer activity but led to cardiotoxicity at non-optimal doses. In this study, we examined the in vivo anti-tumour efficacy and tolerability of a new-generation 2-benzoylpyridine thiosemicarbazone iron chelator (2-benzoylpyridine-4,4-dimethyl-3-thiosemicarbazone; Bp44mT) administered via the oral or i.v. routes. EXPERIMENTAL APPROACH BpT chelators were tested in vitro against human lung cancer cells (DMS-53) and in vivo in DMS-53 tumour xenografts in mice. The toxicity of Bp44mT in vivo and its effects on the expression of iron-regulated molecules involved in growth and cell cycle control were investigated. KEY RESULTS Administration of Bp44mT by either route resulted in marked dose-dependent inhibition of tumour growth. When administered at 50 mg·kg−1 via oral gavage three times per week for 23 days, the net xenograft growth was inhibited by 75%, compared with vehicle-treated mice. Toxicological examination showed reversible alterations including slight reduction of RBC count, with a decrease of liver and splenic iron levels, which confirmed iron chelation in vivo. Importantly, in contrast to Dp44mT, the chelator-treated mice did not show cardiac histological abnormalities. There was also no significant weight loss in mice, suggesting oral administration of Bp44mT was well tolerated. CONCLUSIONS AND IMPLICATIONS This is the first study to show that Bp44mT can be given orally with potent anti-tumour efficacy. Oral administration of a novel and effective chemotherapeutic agent provides the benefits of convenience for chronic dosing regimens. PMID:21658021

  17. Phenyl-1-Pyridin-2yl-Ethanone-Based Iron Chelators Increase IκB-α Expression, Modulate CDK2 and CDK9 Activities, and Inhibit HIV-1 Transcription

    Science.gov (United States)

    Kumari, Namita; Iordanskiy, Sergey; Kovalskyy, Dmytro; Breuer, Denitra; Niu, Xiaomei; Lin, Xionghao; Xu, Min; Gavrilenko, Konstantin; Kashanchi, Fatah; Dhawan, Subhash

    2014-01-01

    HIV-1 transcription is activated by the Tat protein, which recruits CDK9/cyclin T1 to the HIV-1 promoter. CDK9 is phosphorylated by CDK2, which facilitates formation of the high-molecular-weight positive transcription elongation factor b (P-TEFb) complex. We previously showed that chelation of intracellular iron inhibits CDK2 and CDK9 activities and suppresses HIV-1 transcription, but the mechanism of the inhibition was not understood. In the present study, we tested a set of novel iron chelators for the ability to inhibit HIV-1 transcription and elucidated their mechanism of action. Novel phenyl-1-pyridin-2yl-ethanone (PPY)-based iron chelators were synthesized and examined for their effects on cellular iron, HIV-1 inhibition, and cytotoxicity. Activities of CDK2 and CDK9, expression of CDK9-dependent and CDK2-inhibitory mRNAs, NF-κB expression, and HIV-1- and NF-κB-dependent transcription were determined. PPY-based iron chelators significantly inhibited HIV-1, with minimal cytotoxicity, in cultured and primary cells chronically or acutely infected with HIV-1 subtype B, but they had less of an effect on HIV-1 subtype C. Iron chelators upregulated the expression of IκB-α, with increased accumulation of cytoplasmic NF-κB. The iron chelators inhibited CDK2 activity and reduced the amount of CDK9/cyclin T1 in the large P-TEFb complex. Iron chelators reduced HIV-1 Gag and Env mRNA synthesis but had no effect on HIV-1 reverse transcription. In addition, iron chelators moderately inhibited basal HIV-1 transcription, equally affecting HIV-1 and Sp1- or NF-κB-driven transcription. By virtue of their involvement in targeting several key steps in HIV-1 transcription, these novel iron chelators have the potential for the development of new therapeutics for the treatment of HIV-1 infection. PMID:25155598

  18. Kinetic studies on the oxidation of oxyhemoglobin by biologically active iron thiosemicarbazone complexes: relevance to iron-chelator-induced methemoglobinemia.

    Science.gov (United States)

    Basha, Maram T; Rodríguez, Carlos; Richardson, Des R; Martínez, Manuel; Bernhardt, Paul V

    2014-03-01

    The oxidation of oxyhemoglobin to methemoglobin has been found to be facilitated by low molecular weight iron(III) thiosemicarbazone complexes. This deleterious reaction, which produces hemoglobin protein units unable to bind dioxygen and occurs during the administration of iron chelators such as the well-known 3-aminopyridine-2-pyridinecarbaldehyde thiosemicarbazone (3-AP; Triapine), has been observed in the reaction with Fe(III) complexes of some members of the 3-AP structurally-related thiosemicarbazone ligands derived from di-2-pyridyl ketone (HDpxxT series). We have studied the kinetics of this oxidation reaction in vitro using human hemoglobin and found that the reaction proceeds with two distinct time-resolved steps. These have been associated with sequential oxidation of the two different oxyheme cofactors in the α and β protein chains. Unexpected steric and hydrogen-bonding effects on the Fe(III) complexes appear to be the responsible for the observed differences in the reaction rate across the series of HDpxxT ligand complexes used in this study. PMID:24317633

  19. Iron-[S,S']-EDDS (FeEDDS) Chelate as an Iron Source for Horticultural Crop Production: Marigold Growth and Nutrition, Spectral Properties, and Photodegradation

    Science.gov (United States)

    Aminopolycarboxylic acid (APCA) complexones, commonly referred to as ligands or chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to p...

  20. Antioxidant and iron-binding properties of curcumin, capsaicin, and S-allylcysteine reduce oxidative stress in rat brain homogenate.

    Science.gov (United States)

    Dairam, Amichand; Fogel, Ronen; Daya, Santy; Limson, Janice L

    2008-05-14

    Research demonstrates that antioxidants and metal chelators may be of beneficial use in the treatment of neurodegenerative diseases, such as Alzheimer's disease (AD). This study investigated the antioxidant and metal-binding properties of curcumin, capsaicin, and S-allylcysteine, which are major components found in commonly used dietary spice ingredients turmeric, chilli, and garlic, respectively. The DPPH assay demonstrates that these compounds readily scavenge free radicals. These compounds significantly curtail iron- (Fe2+) and quinolinic acid (QA)-induced lipid peroxidation and potently scavenge the superoxide anion generated by 1 mM cyanide in rat brain homogenate. The ferrozine assay was used to measure the extent of Fe2+ chelation, and electrochemistry was employed to measure the Fe3+ binding activity of curcumin, capsaicin, and S-allylcysteine. Both assays demonstrate that these compounds bind Fe2+ and Fe3+ and prevent the redox cycling of iron, suggesting that this may be an additional method through which these agents reduce Fe2+-induced lipid peroxidation. This study demonstrates the antioxidant and metal-binding properties of these spice ingredients, and it is hereby postulate that these compounds have important implications in the prevention or treatment of neurodegenerative diseases such as AD.

  1. Side effects of Deferasirox Iron Chelation in Patients with Beta Thalassemia Major or Intermedia

    Directory of Open Access Journals (Sweden)

    Murtadha Al-Khabori

    2013-03-01

    Full Text Available Objectives: Chelating agents remain the mainstay in reducing the iron burden and extending patient survival in homozygous beta-thalassemia but adverse and toxic effects may increase with the institution and long term use of this essential therapy. This study aimed to estimate the incidence of deferasirox (DFX side effects in patients with thalassemia major or intermedia.Methods: A retrospective study of 72 patients (mean age: 20.3±0.9 yrs; 36 male, 36 female with thalassemia major or intermedia treated at Sultan Qaboos University Hospital, Oman, was performed to assess the incidence of side effects related to deferasirox over a mean of 16.7 month follow-up period.Results: Six patients experienced rashes and 6 had gastro-intestinal upset. DFX was discontinued in 18 patients for the following reasons: persistent progressive rise(s in serum creatinine (7 patients; 40% mean serum creatinine rise from baseline, feeling unwell (2, severe diarrhea (1, pregnancy (1, death unrelated to chelator (2 and rise in serum transaminases (2. Three patients were reverted to desferoxamine and deferiprone combination therapy as DFX was no longer biochemically effective after 18 months of therapy. There was no correlation between baseline serum ferritin and serum creatinine or a rise in serum creatinine. Cardiac MRI T2* did not change with DFX therapy. However, there was an improvement in liver MRI T2* (p=0.013.Conclusion: Renal side effects related to deferasirox appear to be higher than those reported in published clinical trials. Further larger studies are required to confirm these findings.

  2. On improvement in ejection fraction with iron chelation in thalassemia major and the risk of future heart failure

    Directory of Open Access Journals (Sweden)

    Carpenter JP

    2011-09-01

    Full Text Available Abstract Background Trials of iron chelator regimens have increased the treatment options for cardiac siderosis in beta-thalassemia major (TM patients. Treatment effects with improved left ventricular (LV ejection fraction (EF have been observed in patients without overt heart failure, but it is unclear whether these changes are clinically meaningful. Methods This retrospective study of a UK database of TM patients modelled the change in EF between serial scans measured by cardiovascular magnetic resonance (CMR to the relative risk (RR of future development of heart failure over 1 year. Patients were divided into 2 strata by baseline LVEF of 56-62% (below normal for TM and 63-70% (lower half of the normal range for TM. Results A total of 315 patients with 754 CMR scans were analyzed. A 1% absolute increase in EF from baseline was associated with a statistically significant reduction in the risk of future development of heart failure for both the lower EF stratum (EF 56-62%, RR 0.818, p Conclusion These data show that during treatment with iron chelators for cardiac siderosis, small increases in LVEF in TM patients are associated with a significantly reduced risk of the development of heart failure. Thus the iron chelator induced improvements in LVEF of 2.6% to 3.1% that have been observed in randomized controlled trials, are associated with risk reductions of 25.5% to 46.4% for the development of heart failure over 12 months, which is clinically meaningful. In cardiac iron overload, heart mitochondrial dysfunction and its relief by iron chelation may underlie the changes in LV function.

  3. Wild Edible Fruit of Prunus nepalensis Ser. (Steud, a Potential Source of Antioxidants, Ameliorates Iron Overload-Induced Hepatotoxicity and Liver Fibrosis in Mice.

    Directory of Open Access Journals (Sweden)

    Dipankar Chaudhuri

    Full Text Available The antioxidant and restoration potentials of hepatic injury by Prunus nepalensis Ser. (Steud, a wild fruit plant from the Northeastern region of India, were investigated. The fruit extract (PNME exhibited excellent antioxidant and reducing properties and also scavenged the 2,2-diphenyl-1-picrylhydrazyl (DPPH radical (IC50 = 30.92 ± 0.40 μg/ml. PNME demonstrated promising scavenging potency, as assessed by the scavenging of different reactive oxygen and nitrogen species. Moreover, the extract revealed an exceptional iron chelation capacity with an IC50 of 25.64 ± 0.60 μg/ml. The extract induced significant improvement of hepatic injury and liver fibrosis against iron overload induced hepatotoxicity in mice in a dose-dependent manner, and this effect was supported by different histopathological studies. The phytochemical constitutions and their identification by HPLC confirmed the presence of purpurin, tannic acid, methyl gallate, reserpine, gallic acid, ascorbic acid, catechin and rutin. The identified compounds were investigated for their individual radical scavenging and iron chelation activity; some compounds exhibited excellent radical scavenging and iron chelation properties, but most were toxic towards normal cells (WI-38. On the other hand, crude PNME was found to be completely nontoxic to normal cells, suggesting its feasibility as a safe oral drug. The above study suggests that different phytochemicals in PNME contributed to its free radical scavenging and iron chelation activity; however, further studies are required to determine the pathway in which PNME acts to treat iron-overload diseases.

  4. Flotation of a new chelate collector on fine refractory iron ore-containing carbonate

    Institute of Scientific and Technical Information of China (English)

    王婷霞; 朱一民; 桂夏辉

    2016-01-01

    A suitable and efficient flotation collector at normal atmospheric temperature for Donganshan iron ore was developed. A new chelate collector W-2 was synthesized. At 30 °C, condition flotation tests on mixed magnetic concentrate of Donganshan sintering plant established the best reagent system. With the optimum reagent system, one direct flotation and one reverse flotation including one roughing, one cleaning and two scavenging stages have been conducted. After closed-circuit flotation, excellent indices were obtained with grade of siderite concentrate of 36.49%, recovery rate of 10.65%, and loss on ignition of 11.17%, and the grade of hematite concentrate reached 66.27%, with recovery rate of 78.25%, tailing grade of 16.22%, and recovery rate of 11.10%. To analyze the mechanism of action from W-2 to quartz and siderite, zeta potential and FTIR spectra were detected. Results showed that after reaction with W-2, the zeta potential of quartz and siderite evidently changed, which resulted from hydrogen bond between quartz and W-2, and a certain chemical action between siderite and W-2. In addition, the electronegativity equalization principle was used to calculate electronegativity of active adsorption sites and analysis on reagent molecular structure showed that W-2 molecule had five active adsorption sites. Results showed that the electronegativity of atoms N and O in W-2 presented a substantial increase, and the synergy of atomic sites allowed considerable enhancement of collecting ability.

  5. Involvement of type VI secretion system in secretion of iron chelator pyoverdine in Pseudomonas taiwanensis

    Science.gov (United States)

    Chen, Wen-Jen; Kuo, Tzu-Yen; Hsieh, Feng-Chia; Chen, Pi-Yu; Wang, Chang-Sheng; Shih, Yu-Ling; Lai, Ying-Mi; Liu, Je-Ruei; Yang, Yu-Liang; Shih, Ming-Che

    2016-01-01

    Rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most destructive rice diseases worldwide. Therefore, in addition to breeding disease-resistant rice cultivars, it is desirable to develop effective biocontrol agents against Xoo. Here, we report that a soil bacterium Pseudomonas taiwanensis displayed strong antagonistic activity against Xoo. Using matrix-assisted laser desorption/ionization imaging mass spectrometry, we identified an iron chelator, pyoverdine, secreted by P. taiwanensis that could inhibit the growth of Xoo. Through Tn5 mutagenesis of P. taiwanensis, we showed that mutations in genes that encode components of the type VI secretion system (T6SS) as well as biosynthesis and maturation of pyoverdine resulted in reduced toxicity against Xoo. Our results indicated that T6SS is involved in the secretion of endogenous pyoverdine. Mutations in T6SS component genes affected the secretion of mature pyoverdine from the periplasmic space into the extracellular medium after pyoverdine precursor is transferred to the periplasm by the inner membrane transporter PvdE. In addition, we also showed that other export systems, i.e., the PvdRT-OpmQ and MexAB-OprM efflux systems (for which there have been previous suggestions of involvement) and the type II secretion system (T2SS), are not involved in pyoverdine secretion. PMID:27605490

  6. Durable Red Blood Cell Transfusion Independence in a Patient with an MDS/MPN Overlap Syndrome Following Discontinuation of Iron Chelation Therapy

    OpenAIRE

    Harpreet Kochhar; Chantal S. Leger; Leitch, Heather A.

    2015-01-01

    Background. Hematologic improvement (HI) occurs in some patients with acquired anemias and transfusional iron overload receiving iron chelation therapy (ICT) but there is little information on transfusion status after stopping chelation. Case Report. A patient with low IPSS risk RARS-T evolved to myelofibrosis developed a regular red blood cell (RBC) transfusion requirement. There was no response to a six-month course of study medication or to erythropoietin for three months. At 27 months of ...

  7. Iron-chelating and anti-lipid peroxidation properties of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) in long-term iron loadingβ-thalassemic mice

    Institute of Scientific and Technical Information of China (English)

    Kanokwan Kulprachakarn; Nittaya Chansiw; Kanjana Pangjit; Chada Phisalaphong; Suthat Fucharoen; Robert C Hider; Sineenart Santitherakul; Somdet Srichairatanakool

    2014-01-01

    Objective:To evaluate the iron-chelating properties and free-radical scavenging activities of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) treatment in chronic iron-loadedβ-thalassemic (BKO) mice. Methods:The BKO mice were fed with a ferrocene-rich diet and were orally administered with CM1 [50 mg/(kg.day)] for 6 months. Blood levels of non-transferrin bound iron, labile plasma iron, ferritin (Ft) and malondialdehyde were determined. Results:The BKO mice were fed with an iron diet for 8 months which resulted in iron overload. Interestingly, the mice showed a decrease in the non-transferrin bound iron, labile plasma iron and malondialdehyde levels, but not the Ft levels after continuous CM1 treatment. Conclusions:CM1 could be an effective oral iron chelator that can reduce iron overload and lipid peroxidation in chronic iron overloadβ-thalassemic mice.

  8. Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test

    Directory of Open Access Journals (Sweden)

    Barros Marcelo P

    2012-06-01

    Full Text Available Abstract Background Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20 g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1 ± 5.8 years old immediately before and 5 and 60 min after the exhaustive Wingate test. Results Maximum anaerobic power was improved by acute creatine supplementation (10.5 %, but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP, leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects. Conclusions Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent and inherent antioxidant activity of creatine.

  9. Affinity purification of copper chelating peptides from chickpea protein hydrolysates.

    Science.gov (United States)

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-05-16

    Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals.

  10. Immunological Evaluation of -Thalassemia Major Patients Receiving Oral Iron Chelator Deferasirox

    International Nuclear Information System (INIS)

    Objective: To determine the immune abnormalities and occurrence of infections in transfusion-dependent -thalassemia major patients receiving oral iron chelator deferasirox (DFX). Study Design: An observational study. Place and Duration of Study: Hematology Clinics, King Khalid University Hospital, Riyadh, Saudi Arabia, from July to December 2010. Methodology: Seventeen patients with -thalassemia major (12 females, median age 26 years) receiving deferasirox (DFX) for a median duration of 27 months were observed for any infections and had their immune status determined. Immune parameters studied included serum immunoglobulins and IgG subclasses, serum complement (C3 and C4) and anti-nuclear antibody (ANA) level, total B and T-lymphocytes, CD4+ and CD8+ counts, CD4+/CD8+ ratio, and natural killer (NK) cells. Immunological parameters of the patients were compared with age, gender, serum ferritin level and splenectomy status. Lymphocyte subsets were also compared with age and gender matched normal controls. Results: A considerable reduction in serum ferritin was achieved by DFX from a median level of 2528 to 1875 mol/l. Serum IgG levels were increased in 7 patients. Low C4 levels were found in 9 patients. Total B and T-lymphocytes were increased in 14 patients each, while CD4+, CD8+ and NK cells were increased in 13, 12 and 11 patients respectively. Absolute counts for all lymphocyte subsets were significantly higher compared to the normal controls (p=0.05 for all parameters). Raised levels of IgG were associated with older age, female gender, splenectomized status and higher serum ferritin levels but this did not reach statistical significance except for the higher ferritin levels (p=0.044). Increased tendency to infections was not observed. Conclusion: Patients with -thalassemia major receiving DFX exhibited significant immune abnormalities. Changes observed have been described previously, but could be related to DFX. The immune abnormalities were not associated with

  11. Anti-plasmodial activity of aroylhydrazone and thiosemicarbazone iron chelators: effect on erythrocyte membrane integrity, parasite development and the intracellular labile iron pool.

    Science.gov (United States)

    Walcourt, Asikiya; Kurantsin-Mills, Joseph; Kwagyan, John; Adenuga, Babafemi B; Kalinowski, Danuta S; Lovejoy, David B; Lane, Darius J R; Richardson, Des R

    2013-12-01

    Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-resistant (7G8) strains of P. falciparum in culture compared to desferrioxamine (DFO). The present study examined the effects of 311, N4mT and N4pT on erythrocyte membrane integrity and asexual parasite development. While the characteristic biconcave disk shape of the erythrocytes was unaffected, the chelators caused very slight hemolysis at IC50 values that inhibited parasite growth. The chelators 311, N4mT and N4pT affected all stages of the intra-erythrocytic development cycle (IDC) of P. falciparum in culture. However, while these ligands primarily affected the ring-stage, DFO inhibited primarily trophozoite and schizont-stages. Ring, trophozoite and schizont-stages of the IDC were inhibited by significantly lower concentrations of 311, N4mT, and N4pT (IC50=4.45±1.70, 10.30±4.40, and 3.64±2.00μM, respectively) than DFO (IC50=23.43±3.40μM). Complexation of 311, N4mT and N4pT with iron reduced their anti-plasmodial activity. Estimation of the intracellular labile iron pool (LIP) in erythrocytes showed that the chelation efficacy of 311, N4mT and N4pT corresponded to their anti-plasmodial activities, suggesting that the LIP may be a potential source of non-heme iron for parasite metabolism within the erythrocyte. This study has implications for malaria chemotherapy that specifically disrupts parasite iron utilization. PMID:24028863

  12. Removal of Fe3+ and Zn2+ from plasma metalloproteins by iron chelating therapeutics depicted with SEC-ICP-AES.

    Science.gov (United States)

    Sooriyaarachchi, Melani; Gailer, Jürgen

    2010-08-28

    The iron chelation therapy drugs desferrioxamine B (DFO) and deferiprone (DFP) are used to treat iron overload patients, but not much is known about their adverse effects on other essential metals in vivo. After the addition of a clinically relevant dose of DFP or an equimolar dose of DFO to human plasma in vitro, the mixtures were analyzed by size exclusion chromatography (SEC) coupled to an inductively coupled plasma atomic emission spectrometer (ICP-AES). Simultaneous detection of the emission lines of copper, iron and zinc allowed the visualization of changes that these drugs exerted at the metalloprotein level. After the addition of DFP, a metalloprotein level. Thus, SEC-ICP-AES emerges as a useful analytical tool to visualize health-relevant bioinorganic chemistry-related reactions of medicinal drugs in blood plasma in vitro.

  13. Longitudinal MRI and Ferritin Monitoring of Iron Overload in Chronically Transfused and Chelated Children With Sickle Cell Anemia and Thalassemia Major.

    Science.gov (United States)

    Aubart, Mélodie; Ou, Phalla; Elie, Caroline; Canniffe, Carla; Kutty, Shelby; Delos, Vincent; Graffigne, Christine; de Montalembert, Mariane; Brousse, Valentine

    2016-10-01

    Iron overload is an ineluctable complication in chronically transfused children warranting accurate assessment to avoid related morbidity. We investigated longitudinally the relationships between ferritin levels and hepatic and cardiac T2* magnetic resonance imaging (MRI) in a cohort of chronically transfused children receiving chelation therapy. Thirty children with sickle cell anemia (SCA) and 7 with thalassemia major (TM) chelated similarly by deferasirox were analyzed. Sex ratio, age, median duration of transfusion programs (5 y; range, 2 to 14 y), median transfusion iron intake 0.54 mg/kg/d (range, 0.27 to 0.74 mg/kg/d), and median ferritin level (1550 mg/L; range, 184 to 6204 mg/L) were comparable in TM and SCA. A significant relation was found between ferritin level and transfusion iron intake (P<0.001) despite chelation therapy. Analysis of 73 hepatic T2* MRI performed yearly demonstrated severe hepatic iron overload (≥14 mg/g) in 38.3% cases and a strong relationship between serum ferritin level and liver iron content both in SCA and TM (P<0.001). Analysis of 55 cardiac T2* MRI measurements found no cardiac overload in patients with SCA. Cardiac iron overload was moderate in 4 cases and severe in 1 case of TM. In almost half the cases, ferritin trend correctly predicted hepatic iron trend, both in patients with SCA and TM but failed to predict cardiac iron trend, notably in TM patients. Despite chelation therapy, iron burden in chronically transfused patients remains a threat. Ferritin levels are associated with liver iron overload in chelated children with SCA and TM, but iron burden should be best monitored with MRI whenever the setting allows it. PMID:27548334

  14. Iron Chelators of the Di-2-pyridylketone Thiosemicarbazone and 2-Benzoylpyridine Thiosemicarbazone Series Inhibit HIV-1 Transcription: Identification of Novel Cellular Targets—Iron, Cyclin-Dependent Kinase (CDK) 2, and CDK9S⃞

    OpenAIRE

    Debebe, Zufan; Ammosova, Tatyana; Breuer, Denitra; Lovejoy, David B.; Kalinowski, Danuta S.; Karla, Pradeep K.; Kumar, Krishna; Jerebtsova, Marina; Ray, Patricio; KASHANCHI, FATAH; Gordeuk, Victor R; Richardson, Des R.; Nekhai, Sergei

    2011-01-01

    HIV-1 transcription is activated by HIV-1 Tat protein, which recruits cyclin-dependent kinase 9 (CDK9)/cyclin T1 and other host transcriptional coactivators to the HIV-1 promoter. Tat itself is phosphorylated by CDK2, and inhibition of CDK2 by small interfering RNA, the iron chelator 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), and the iron chelator deferasirox (ICL670) inhibits HIV-1 tran...

  15. Deferoxamine alleviates chronic hydrocephalus after intraventricular hemorrhage through iron chelation and Wnt1/Wnt3a inhibition.

    Science.gov (United States)

    Meng, Hui; Li, Fei; Hu, Rong; Yuan, Yikai; Gong, Guoqi; Hu, Shengli; Feng, Hua

    2015-03-30

    Post-hemorrhagic chronic hydrocephalus (PHCH) is a common complication after intraventricular hemorrhage (IVH). The mechanism of PHCH is not fully understood, and its treatment is relatively difficult. In the present study, a rat model of PHCH was used to elucidate the role of iron in the pathogenesis of PHCH. The action of deferoxamine (DFX) in IVH-induced PHCH, the expression of brain ferritin, the concentration of iron in cerebrospinal fluid (CSF), and changes in Wnt1/Wnt3a gene expression were determined. Results indicate that iron plays an important role in the occurrence of hydrocephalus after IVH. The iron chelator, DFX, can decrease the concentrations of iron and ferritin after cerebral hemorrhage and can thereby decrease the incidence of hydrocephalus. In addition, after IVH, the gene expression of Wnt1 and Wnt3a was enhanced, with protein expression also upregulated; DFX was able to suppress both gene and protein expression of Wnt1 and Wnt3a in brain tissue. This indicates that iron may be the key stimulus that activates the Wnt signaling pathway and regulates subarachnoid fibrosis after cerebral hemorrhage, and that DFX may be a candidate for preventing PHCH in patients with IVH.

  16. Antidiabetic and pancreas-protective effects of zinc threoninate chelate in diabetic rats may be associated with its antioxidative stress ability.

    Science.gov (United States)

    Zhu, Kexue; Nie, Shaoping; Li, Chuan; Huang, Jianqin; Hu, Xiaobo; Li, Wenjuan; Gong, Deming; Xie, Mingyong

    2013-06-01

    Zinc exerts a wide range of important biological roles. The present study was carried out to investigate the effects of zinc threoninate chelate in blood glucose levels, lipid peroxidation, activities of antioxidant defense systems and nitrite concentration, and histology of the pancreas in diabetic rats. Wistar rats were intravenously injected with a single dose of streptozotocin to induce diabetes. Then, diabetic rats were administrated orally with zinc threoninate chelate (3, 6, and 9 mg/kg body weight) once daily for 7 weeks. Fasting blood glucose was monitored weekly. At the end of the experimental period, the diabetic rats were killed, and levels of serum insulin, malondialdehyde, and nitric oxide, activities of glutathione peroxidase, total superoxide dismutase, copper/zinc-superoxide dismutase, and nitric oxide synthase were determined; pancreas was examined histopathologically as well. Zinc threoninate chelate significantly reduced the blood glucose levels and significantly increased the serum insulin levels in diabetic rats. In addition, zinc threoninate chelate caused a significant increase in activities of antioxidant enzymes and significant decrease in nitrite concentration and malondialdehyde formation in the pancreas and serum of diabetic rats. These biochemical observations were supplemented by histopathological examination of the pancreas. These results suggested that the antidiabetic effect of zinc threoninate chelate may be related to its antioxidative stress ability in diabetic rats.

  17. Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial

    DEFF Research Database (Denmark)

    Lee, Jong Wook; Yoon, Sung-Soo; Shen, Zhi Xiang;

    2010-01-01

    The prospective 1-year Evaluation of Patients' Iron Chelation with Exjade (EPIC) study enrolled a large cohort of 116 patients with aplastic anemia; the present analyses evaluated the efficacy and safety of deferasirox in this patient population. After 1 year, median serum ferritin decreased...... neutrophil and platelet counts remained stable during treatment, and there were no drug-related cytopenias. This prospective dataset confirms the efficacy and well characterizes the tolerability profile of deferasirox in a large population of patients with aplastic anemia. This study was registered at www...

  18. Novel enterobactin analogues as potential therapeutic chelating agents: Synthesis, thermodynamic and antioxidant studies

    Science.gov (United States)

    Zhang, Qingchun; Jin, Bo; Shi, Zhaotao; Wang, Xiaofang; Liu, Qiangqiang; Lei, Shan; Peng, Rufang

    2016-09-01

    A series of novel hexadentate enterobactin analogues, which contain three catechol chelating moieties attached to different molecular scaffolds with flexible alkyl chain lengths, were prepared. The solution thermodynamic stabilities of the complexes with uranyl, ferric(III), and zinc(II) ions were then investigated. The hexadentate ligands demonstrate effective binding ability to uranyl ion, and the average uranyl affinities are two orders of magnitude higher than 2,3-dihydroxy-N1,N4-bis[(1,2-hydroxypyridinone-6-carboxamide)ethyl]terephthalamide [TMA(2Li-1,2-HOPO)2] ligand with similar denticity. The high affinity of hexadentate ligands could be due to the presence of the flexible scaffold, which favors the geometric agreement between the ligand and the uranyl coordination preference. The hexadentate ligands also exhibit higher antiradical efficiency than butylated hydroxyanisole (BHA). These results provide a basis for further studies on the potential applications of hexadentate ligands as therapeutic chelating agents.

  19. Safety of deferasirox as an oral iron chelator in thalassemic children

    OpenAIRE

    Shikha Jaiswal; Rajesh Hishikar; Basant Maheshwari; Onkar Khandwal; Raka Sheohare

    2016-01-01

    Background: Thalassemia major patients require frequent blood transfusion leading to iron overload. Iron overload is characterized by excessive iron deposition and consequent injury and dysfunction of the heart, liver, anterior pituitary, pancreas, and joints. Because physiologic mechanisms to excrete iron are very limited, patients with iron overload and its complications need safe, effective therapy that is compatible with their coexisting medical conditions. Current prospective, observatio...

  20. Quantitative Analysis of the Anti-Proliferative Activity of Combinations of Selected Iron-Chelating Agents and Clinically Used Anti-Neoplastic Drugs

    OpenAIRE

    Eliska Potuckova; Hana Jansova; Miloslav Machacek; Anna Vavrova; Pavlina Haskova; Lucie Tichotova; Vera Richardson; Kalinowski, Danuta S.; Richardson, Des R.; Tomas Simunek

    2014-01-01

    Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, ...

  1. Curcumin protects nigral dopaminergic neurons by iron-chelation in the 6-hydroxydopamine rat model of Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    Xi-Xun Du; Hua-Min Xu; Hong Jiang; Ning Song; Jun Wang; Jun-Xia Xie

    2012-01-01

    [Objective] Curcumin is a plant polyphenolic compound and a major component of spice turmeric (Curcuma longa).It has been reported to possess free radical-scavenging,iron-chelating,and anti-inflammatory properties in different tissues.Our previous study showed that curcumin protects MES23.5 dopaminergic cells from 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro.The present study aimed to explore this neuroprotective effect in the 6-OHDAlesioned rat model of Parkinson's disease in vivo.[Methods] Rats were given intragastric curcumin for 24 days.6-OHDA lesioning was conducted on day 4 of curcumin treatment.Dopamine content was assessed by high-performance liquid chromatography with electrochemical detection,tyrosine hydroxylase (TH)-containing neurons by immunohistochemistry,and iron-containing cells by Perls' iron staining.[Results] The dopamine content in the striatum and the number of THimmunoreactive neurons decreased after 6-OHDA treatment.Curcumin pretreatment reversed these changes.Further studies demonstrated that 6-OHDA treatment increased the number of iron-staining cells,which was dramatically decreased by curcumin pretreatment.[Conclusion]The protective effects of curcumin against 6-OHDA may be attributable to the ironchelating activity of curcumin to suppress the iron-induced degeneration of nigral dopaminergic neurons.

  2. Effects of metal ion chelators on DNA strand breaks and inactivation produced by hydrogen peroxide in Escherichia coli: detection of iron-independent lesions.

    OpenAIRE

    Asad, N R; A.C. Leitão

    1991-01-01

    In order to study the role of metallic ions in the H2O2 inactivation of Escherichia coli cells, H2O2-sensitive mutants were treated with metal ion chelators and then submitted to H2O2 treatment. o-Phenanthroline, dipyridyl, desferrioxamine, and neocuproine were used as metal chelators. Cell sensitivity to H2O2 treatment was not modified by neocuproine, suggesting that copper has a minor role in OH production in E. coli. On the other hand, prior treatment with iron chelators protected the cell...

  3. Neuroprotective effect of the natural iron chelator, phytic acid in a cell culture model of Parkinson's disease

    International Nuclear Information System (INIS)

    Disrupted iron metabolism and excess iron accumulation has been reported in the brains of Parkinson's disease (PD) patients. Because excessive iron can induce oxidative stress subsequently causing degradation of nigral dopaminergic neurons in PD, we determined the protective effect of a naturally occurring iron chelator, phytic acid (IP6), on 1-methyl-4-phenylpyridinium (MPP+)-induced cell death in immortalized rat mesencephalic/dopaminergic cells. Cell death was induced with MPP+ in normal and iron-excess conditions and cytotoxicity was measured by thiazolyl blue tetrazolium bromide (MTT assay) and trypan blue staining. Apoptotic cell death was also measured with caspase-3 activity, DNA fragmentation, and Hoechst nuclear staining. Compared to MPP+ treatment, IP6 (30 μmol/L) increased cell viability by 19% (P + treatment was decreased by 55% (P < 0.01) and 52% (P < 0.05), respectively with IP6. Cell survival was increased by 18% (P < 0.05) and 42% (P < 0.001) with 30 and 100 μmol/L of IP6, respectively in iron-excess conditions. A 40% and 52% (P < 0.001) protection was observed in caspase-3 activity with 30 and 100 μmol/L IP6, respectively in iron-excess condition. Similarly, a 45% reduction (P < 0.001) in DNA fragmentation was found with 100 μmol/L IP6. In addition, Hoechst nuclear staining results confirmed the protective effect of IP6 against apoptosis. Similar protection was also observed with the differentiated cells. Collectively, our results demonstrate a significant neuroprotective effect of phytate in a cell culture model of PD

  4. Iron chelation with deferasirox for the treatment of secondary hemosiderosis in pediatric oncology patients: a single-center experience.

    Science.gov (United States)

    Ktena, Yiouli P; Athanasiadou, Anastasia; Lambrou, George; Adamaki, Maria; Moschovi, Maria

    2013-08-01

    Pediatric oncology patients are often iron overloaded, due to the multiple blood transfusions necessary during the course of chemotherapy. Our aim is to report the efficacy and safety of deferasirox, an oral iron chelator, in this patient group. Deferasirox was administered to 13 children with malignancies in remission and iron overload. Ferritin, blood urea nitrogen, creatinine, transaminases, and bilirubin were recorded at 4- to 8-week intervals, and hepatic and cardiac iron overload were assessed with magnetic resonance imaging before initiation of treatment. Deferasirox was administered for an average of 6 months (SD=4.5; range, 0.3 to 18.2). Two children presented with skin rash, 1 with gastrointestinal disturbances, and 1 with fully reversible acute renal failure. The mean monthly rate of change in ferritin levels was -10.8 μg/L before initiation of treatment (95% confidence interval [CI], -19.8 to -1.8; P=0.02) and -93.6 μg/L during deferasirox treatment (95% CI, -118.1 to -69.1; Piron burden. The adverse effects were easily monitored and managed. Further studies are warranted to investigate the effect of deferasirox on mortality and morbidity in this population.

  5. Curcumin Inhibits Growth of Saccharomyces cerevisiae through Iron Chelation ▿ ††

    OpenAIRE

    Minear, Steven; O'Donnell, Allyson F.; Ballew, Anna; Giaever, Guri; Nislow, Corey; Stearns, Tim; Martha S Cyert

    2011-01-01

    Curcumin, a polyphenol derived from turmeric, is an ancient therapeutic used in India for centuries to treat a wide array of ailments. Interest in curcumin has increased recently, with ongoing clinical trials exploring curcumin as an anticancer therapy and as a protectant against neurodegenerative diseases. In vitro, curcumin chelates metal ions. However, although diverse physiological effects have been documented for this compound, curcumin's mechanism of action on mammalian cells remains un...

  6. "Evaluation Of compliance To Iron Chelation Therapy With Defe-Roxamine In Patients With Major Thalassemia In Iran In 2004 "

    Directory of Open Access Journals (Sweden)

    M. Izadyar

    2006-06-01

    Full Text Available Background and Aim: With the introduction of long term subcutaneous administration of Deferoxamine there has been a decline in the morbidity and mortality of transfusion-dependent beta thalassemia patients. But parenteral iron chelation therapy is still a burden and a major reason for unsatisfactory compliance and places an additional psychological burden on the patients. There are some factors contributing to low compliance in these patients. To evaluate compliance to Deferoxamine and barriers of non adherence and assessment the prevalence of depression and it’s association with compliance. Materials and Methods: 205 patients with major thalassemia in children medical center older than 6 years old were included. They were classified in 3 groups by compliance index (CI: No. of days of treatment per one month/No. of treatment days prescribed by physician. CI>75 % was considered good ,CI< 50-75%: moderate,CI<50%:weak and 3d group the patients without compliance. For assessment of depression: Beck Depression questionnaires were given to the patients older than 18 years old and Children Depression Inventories (CDI“kovacs” were given to the rest Results: Of 205 patients (110 females (54% and 95 males (46%, 13.3% were non compliant, 14% had poor compliance, 62.7% had good compliance. Females were more compliant than males (P=0.034. Compliance improved in older age groups meaningfully (P=0.037. There was negative association between compliance and serum ferritin level (P=0.02. 22% of children and 12% of Adults had severe depression according to the questionnaires. There was no association between compliance and depression. The most prevalent problem rgarding Desferal injection was local reactions in injection site (83%. Conclusion: As oral chelation therapies are not used routinely, more investigations regarding the noncompliance must be considered; and this method of chelation therapy must be encouraged. Compliance is a multifactorial problem

  7. Ulcerated hemosiderinic dyschromia and iron deposits within lower limbs treated with a topical application of biological chelator

    Directory of Open Access Journals (Sweden)

    Eugenio Brizzio

    2012-12-01

    Full Text Available The ulcerative haemosiderinic dyschromia of chronic venous insufficiency is difficult to heal and presents a high accumulation of iron. Lactoferrin, a potent natural iron chelator, could help to scar this ulcerative haemosi - derinic dyschromia. The objective of this study was to determine whether the topical application of a liposomal gel with Lactoferrin favors scarring/degradation of the brown colored spot typical of ulcerative haemosiderinic dyschromia. Nine patients with severe chronic venous insufficiency and ulcerative haemosiderinic dyschromia (CEAP-C6, with a natural evolution of over 12 months, were included in the study. Hemo chromatosis gene mutations were investigated. The levels of serum ferritin, transferrin saturation and blood cell counts were analyzed. The presence of hemosiderin was investigated through periulcerous and ulcer fundus biopsies carried out at baseline and 30 days after treatment with Lactoferrin. The severity of the injuries (CEAP classification was evaluated at the beginning of and throughout the whole 3-month treatment period. No patient had received compression treatment during the three months previous to this therapy. Significant improvement in these injuries, with a reduction in the dimensions of the brown spot (9 of 9 at Day 90, and complete scarring with a closure time ranging from 15 to 180 days (7 of 9 were observed. The use of topical lactoferrin is a non-invasive therapeutic tool that favors clearance of hemosiderinic dyschromia and scarring of the ulcer. The success of this study was not influenced either by the hemochromatosis genetics or the iron metabolism profile observed.

  8. Profound morphological changes in the erythrocytes and fibrin networks of patients with hemochromatosis or with hyperferritinemia, and their normalization by iron chelators and other agents.

    Directory of Open Access Journals (Sweden)

    Etheresia Pretorius

    Full Text Available It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH, as well as some who displayed hyperferritinemia (HF. Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators. These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded ('free' iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise.

  9. Impact of two iron(III) chelators on the iron, cadmium, lead and nickel accumulation in poplar grown under heavy metal stress in hydroponics.

    Science.gov (United States)

    Mihucz, Victor G; Csog, Árpád; Fodor, Ferenc; Tatár, Enikő; Szoboszlai, Norbert; Silaghi-Dumitrescu, Luminiţa; Záray, Gyula

    2012-04-15

    Poplar (Populus jacquemontiana var. glauca cv. Kopeczkii) was grown in hydroponics containing 10 μM Cd(II), Ni(II) or Pb(II), and Fe as Fe(III) EDTA or Fe(III) citrate in identical concentrations. The present study was designed to compare the accumulation and distribution of Fe, Cd, Ni and Pb within the different plant compartments. Generally, Fe and heavy-metal accumulation were higher by factor 2-7 and 1.6-3.3, respectively, when Fe(III) citrate was used. Iron transport towards the shoot depended on the Fe(III) chelate and, generally, on the heavy metal used. Lead was accumulated only in the root. The amounts of Fe and heavy metals accumulated by poplar were very similar to those of cucumber grown in an identical way, indicating strong Fe uptake regulation of these two Strategy I plants: a cultivar and a woody plant. The Strategy I Fe uptake mechanism (i.e. reducing Fe(III) followed by Fe(II) uptake), together with the Fe(III) chelate form in the nutrient solution had significant effects on Fe and heavy metal uptake. Poplar appears to show phytoremediation potential for Cd and Ni, as their transport towards the shoot was characterized by 51-54% and 26-48% depending on the Fe(III) supply in the nutrient solution.

  10. Effects of feed supplementation with glycine chelate and iron sulfate on selected parameters of cell-mediated immune response in broiler chickens.

    Science.gov (United States)

    Jarosz, Łukasz; Kwiecień, Małgorzata; Marek, Agnieszka; Grądzki, Zbigniew; Winiarska-Mieczan, Anna; Kalinowski, Marcin; Laskowska, Ewa

    2016-08-01

    Because little is known about the impact of chelated (Fe-Gly, Fe-Gly+F) and inorganic (FeSO4, FeSO4+F) iron products on immune response parameters in broiler chickens, the objective of the study was to determine the effects of inorganic and organic forms of iron on selected parameters of the cell-mediated immune response in broiler chickens by assessing the percentage of CD3(+)CD4(+), CD3(+)CD8(+), CD25(+), and MHC Class II lymphocytes, as well as the CD4(+)/CD8(+) ratio and IL-2 concentration in the peripheral blood. The experiments were conducted using 50day-old Ross 308 roosters. The test material was peripheral blood. Flow cytometry was used to determine selected cell-mediated immune response parameters. The results obtained indicate that the use of iron chelates in the diet of broiler chickens may stimulate cellular defense mechanisms. As a result of the experiment an increase was observed in the percentage of Th1, mainly T CD4(+) and T CD8(+). It was also noted that application of chelated iron can increase production of T CD8(+) cytotoxic cells and IL-2, which promotes the body's natural response to developing inflammation. There were no changes in T CD4(+), T CD8(+), T CD25(+) or MHC II lymphocyte subpopulations in the chickens following application of the inorganic form of iron.

  11. Preservation of glutamic acid-iron chelate into montmorillonite to efficiently degrade Reactive Blue 19 in a Fenton system under sunlight irradiation at neutral pH

    Science.gov (United States)

    Huang, Zhujian; Wu, Pingxiao; Gong, Beini; Yang, Shanshan; Li, Hailing; Zhu, Ziao; Cui, Lihua

    2016-05-01

    To further enhance the visible light responsive property and the chemical stability of Fe/clay mineral catalysts, glutamic acid-iron chelate intercalated montmorillonite (G-Fe-Mt) was developed. The physiochemical properties of G-Fe-Mt were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), etc. The results showed that glutamic acid-iron chelates were successfully intercalated into the gallery of montmorillonite and the intercalated glutamic acid-iron chelate molecules were well preserved. The product G-Fe-Mt displayed excellent catalytic performance in heterogeneous photo-Fenton reaction under sunlight irradiation at acidic and neutral pH values. The chelation and the visible light responsiveness of glutamic acid produce a synergistic effect leading to greatly enhanced sunlight-Fenton reaction catalyzed by the heterogeneous G-Fe-Mt under neutral pH. G-Fe-Mt is a promising catalyst for advanced oxidation processes.

  12. Iron Chelators of the Di-2-pyridylketone Thiosemicarbazone and 2-Benzoylpyridine Thiosemicarbazone Series Inhibit HIV-1 Transcription: Identification of Novel Cellular Targets—Iron, Cyclin-Dependent Kinase (CDK) 2, and CDK9S⃞

    Science.gov (United States)

    Debebe, Zufan; Ammosova, Tatyana; Breuer, Denitra; Lovejoy, David B.; Kalinowski, Danuta S.; Karla, Pradeep K.; Kumar, Krishna; Jerebtsova, Marina; Ray, Patricio; Kashanchi, Fatah; Gordeuk, Victor R.; Richardson, Des R.

    2011-01-01

    HIV-1 transcription is activated by HIV-1 Tat protein, which recruits cyclin-dependent kinase 9 (CDK9)/cyclin T1 and other host transcriptional coactivators to the HIV-1 promoter. Tat itself is phosphorylated by CDK2, and inhibition of CDK2 by small interfering RNA, the iron chelator 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), and the iron chelator deferasirox (ICL670) inhibits HIV-1 transcription. Here we have analyzed a group of novel di-2-pyridylketone thiosemicarbazone- and 2-benzoylpyridine thiosemicarbazone-based iron chelators that exhibit marked anticancer activity in vitro and in vivo (Proc Natl Acad Sci USA 103:7670–7675, 2006; J Med Chem 50:3716–3729, 2007). Several of these iron chelators, in particular 2-benzoylpyridine 4-allyl-3-thiosemicarbazone (Bp4aT) and 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT), inhibited HIV-1 transcription and replication at much lower concentrations than did 311 and ICL670. Neither Bp4aT nor Bp4eT were toxic after a 24-h incubation. However, longer incubations for 48 h or 72 h resulted in cytotoxicity. Analysis of the molecular mechanism of HIV-1 inhibition showed that the novel iron chelators inhibited basal HIV-1 transcription, but not the nuclear factor-κB-dependent transcription or transcription from an HIV-1 promoter with inactivated SP1 sites. The chelators inhibited the activities of CDK2 and CDK9/cyclin T1, suggesting that inhibition of CDK9 may contribute to the inhibition of HIV-1 transcription. Our study suggests the potential usefulness of Bp4aT or Bp4eT in antiretroviral regimens, particularly where resistance to standard treatment occurs. PMID:20956357

  13. Iron and exercise induced alterations in antioxidant status. Protection by dietary milk proteins.

    Science.gov (United States)

    Zunquin, Gautier; Rouleau, Vincent; Bouhallab, Said; Bureau, Francois; Theunynck, Denis; Rousselot, Pierre; Arhan, Pierre; Bougle, Dominique

    2006-05-01

    Lipid peroxidation stress induced by iron supplementation can contribute to the induction of gut lesions. Intensive sports lead to ischemia reperfusion, which increases free radical production. Athletes frequently use heavy iron supplementation, whose effects are unknown. On the other hand, milk proteins have in vitro antioxidant properties, which could counteract these potential side effects. The main aims of the study were: (1) to demonstrate the effects of combined exercise training (ET) and iron overload on antioxidant status; (2) to assess the protective properties of casein in vivo; (3) to study the mechanisms involved in an in vitro model. Antioxidant status was assessed by measuring the activity of antioxidant enzymes (superoxide dismutase (SOD); glutathione peroxidase (GSH-Px)), and on the onset of aberrant crypts (AC) in colon, which can be induced by lipid peroxidation. At day 30, all ET animals showed an increase in the activity of antioxidant enzymes, in iron concentration in colon mucosa and liver and in the number of AC compared to untrained rats. It was found that Casein's milk protein supplementation significantly reduced these parameters. Additional information on protective effect of casein was provided by measuring the extent of TBARS formation during iron/ascorbate-induced oxidation of liposomes. Free casein and casein bound to iron were found to significantly reduce iron-induced lipid peroxidation. The results of the overall study suggest that Iron supplementation during intensive sport training would decrease anti-oxidant status. Dietary milk protein supplementation could at least partly prevent occurrence of deleterious effects to tissue induced by iron overload. PMID:17390518

  14. Characterisation of powerful antioxidants and synthetic iron ligands, as protective agents against oxidative damages, using new high throughput screening assays

    International Nuclear Information System (INIS)

    This work was devoted to the development of pertinent high throughput screening assays in the aim of studying oxidative stress. Three screening assays have been developed for the evaluation of protective agents toward ROS generated by gamma irradiation, UV or by a Fenton-like system. 24 natural extracts and a library of 120 pure compounds, containing among the most powerful antioxidants known to date, have been readily studied using, these new techniques. We found that two pulvinic acid derivatives possess excellent protective properties, and especially a pigment of fungus named norbadione A. Beyond its in vitro activity, this molecule displays remarkable biological properties. In the aim of studying an alternative pathway of protection against oxidation induced by iron, ligands able to modify the redox properties of this metal, have been synthesised. We have developed a parallel synthesis allowing the variation of the architecture, denticity, chelating moieties and hydrophobicity of iron chelates. Using this strategy, 47 potential Fe(III) ligands were obtained. Their protective capacities have been studied using a fourth screening assay, demonstrating the effectiveness of some ligands. Finally, the immunoassay technique called SPI-RAD has been used in order to study a particular consequence of drastic oxidative stress, namely covalent crosslinks between proteins. Our results demonstrate that these linkages occur in the presence of metals (FeII or CuII) and hydrogen peroxide, as well as in the presence of NO. radical. Moreover, it has been demonstrated that tyrosines residues and disulfide bridges play an important role in these phenomena. (author)

  15. Green tea or rosemary extract added to foods reduces nonheme- iron absorption

    DEFF Research Database (Denmark)

    Samman, S.; Sandstrøm, B.; Toft, M.B.;

    2001-01-01

    Background: Phenolic compounds act as food antioxidants. One of the postulated mechanisms of action is chelation of prooxidant metals, such as iron. Although the antioxidative effect is desirable, this mechanism may impair the utilization of dietary iron. Objective: We sought to determine...

  16. Investigation of antioxidant property of iron oxide particles by 1'-1'diphenylpicryl-hydrazyle (DPPH) method

    Energy Technology Data Exchange (ETDEWEB)

    Paul, S. [Department of Energy, Tezpur University, Tezpur 784028 (India)], E-mail: paul.tezu@gmail.com; Saikia, J.P. [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028 (India); Samdarshi, S.K. [Department of Energy, Tezpur University, Tezpur 784028 (India)], E-mail: drsksamdarshi@rediffmail.com; Konwar, B.K. [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028 (India)

    2009-11-15

    We investigated the antioxidant properties of iron oxide particles. Particles of different sizes were synthesized and their antioxidant potency was investigated by using an in vitro system. The antioxidant capacity assay was done via a modified DPPH method for insoluble solid materials. The percentages of DPPH scavenging were calculated for iron oxide particles. The particles were found to show antioxidant potency. The DPPH scavenging increases with decrease in particle size.

  17. Investigation of antioxidant property of iron oxide particlesby 1‧-1‧diphenylpicryl-hydrazyle (DPPH) method

    Science.gov (United States)

    Paul, S.; Saikia, J. P.; Samdarshi, S. K.; Konwar, B. K.

    2009-11-01

    We investigated the antioxidant properties of iron oxide particles. Particles of different sizes were synthesized and their antioxidant potency was investigated by using an in vitro system. The antioxidant capacity assay was done via a modified DPPH method for insoluble solid materials. The percentages of DPPH scavenging were calculated for iron oxide particles. The particles were found to show antioxidant potency. The DPPH scavenging increases with decrease in particle size.

  18. Investigation of antioxidant property of iron oxide particles by 1'-1'diphenylpicryl-hydrazyle (DPPH) method

    International Nuclear Information System (INIS)

    We investigated the antioxidant properties of iron oxide particles. Particles of different sizes were synthesized and their antioxidant potency was investigated by using an in vitro system. The antioxidant capacity assay was done via a modified DPPH method for insoluble solid materials. The percentages of DPPH scavenging were calculated for iron oxide particles. The particles were found to show antioxidant potency. The DPPH scavenging increases with decrease in particle size.

  19. Structural and Antioxidant Properties of Compounds Obtained from Fe2+ Chelation by Juglone and Two of Its Derivatives: DFT, QTAIM, and NBO Studies

    Science.gov (United States)

    Tamafo Fouegue, Aymard Didier; Bikélé Mama, Désiré; Nkungli, Nyiang Kennet; Younang, Elie

    2016-01-01

    The chelating ability of juglone and two of its derivatives towards Fe2+ion and the antioxidant activity (AOA) of the resulting chelates and complexes (in the presence of H2O and CH3OH as ligands) in gas phase is reported via bond dissociation enthalpy, ionization potential, proton dissociation enthalpy, proton affinity, and electron transfer enthalpy. The DFT/B3LYP level of theory associated with the 6-31+G(d,p) and 6-31G(d) Pople-style basis sets on the atoms of the ligands and the central Fe(II), respectively, was used. Negative chelation free energies obtained revealed that juglone derivatives possessing the O-H substituent (L2) have the greatest ability to chelate Fe2+ ion. Apart from 1B, thermodynamic descriptors of the AOA showed that the direct hydrogen atom transfer is the preferred mechanism of the studied molecules. NBO analysis showed that the Fe-ligand bonds are all formed through metal to ligand charge transfer. QTAIM studies revealed that among all the Fe-ligand bonds, the O1-Fe bond of 1A is purely covalent. The aforementioned results show that the ligands can be used to fight against Fe(II) toxicity, thus preserving human health, and fight against the deterioration of industrial products. In addition, most of the complexes studied have shown a better AOA than their corresponding ligands.

  20. Chelation in Metal Intoxication

    Directory of Open Access Journals (Sweden)

    Swaran J.S. Flora

    2010-06-01

    Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

  1. Antimalarial iron chelator, FBS0701, shows asexual and gametocyte Plasmodium falciparum activity and single oral dose cure in a murine malaria model.

    Directory of Open Access Journals (Sweden)

    Patricia Ferrer

    Full Text Available Iron chelators for the treatment of malaria have proven therapeutic activity in vitro and in vivo in both humans and mice, but their clinical use is limited by the unsuitable absorption and pharmacokinetic properties of the few available iron chelators. FBS0701, (S3"-(HO-desazadesferrithiocin-polyether [DADFT-PE], is an oral iron chelator currently in Phase 2 human studies for the treatment of transfusional iron overload. The drug has very favorable absorption and pharmacokinetic properties allowing for once-daily use to deplete circulating free iron with human plasma concentrations in the high µM range. Here we show that FBS0701 has inhibition concentration 50% (IC(50 of 6 µM for Plasmodium falciparum in contrast to the IC(50 for deferiprone and deferoxamine at 15 and 30 µM respectively. In combination, FBS0701 interfered with artemisinin parasite inhibition and was additive with chloroquine or quinine parasite inhibition. FBS0701 killed early stage P. falciparum gametocytes. In the P. berghei Thompson suppression test, a single dose of 100 mg/kg reduced day three parasitemia and prolonged survival, but did not cure mice. Treatment with a single oral dose of 100 mg/kg one day after infection with 10 million lethal P. yoelii 17XL cured all the mice. Pretreatment of mice with a single oral dose of FBS0701 seven days or one day before resulted in the cure of some mice. Plasma exposures and other pharmacokinetics parameters in mice of the 100 mg/kg dose are similar to a 3 mg/kg dose in humans. In conclusion, FBS0701 demonstrates a single oral dose cure of the lethal P. yoelii model. Significantly, this effect persists after the chelator has cleared from plasma. FBS0701 was demonstrated to remove labile iron from erythrocytes as well as enter erythrocytes to chelate iron. FBS0701 may find clinically utility as monotherapy, a malarial prophylactic or, more likely, in combination with other antimalarials.

  2. Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

    Science.gov (United States)

    Siriwardana, Gamini; Seligman, Paul A

    2013-12-01

    Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points. PMID:24744856

  3. Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

    Science.gov (United States)

    Siriwardana, Gamini; Seligman, Paul A

    2013-12-01

    Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

  4. Quantitative analysis of the anti-proliferative activity of combinations of selected iron-chelating agents and clinically used anti-neoplastic drugs.

    Directory of Open Access Journals (Sweden)

    Eliska Potuckova

    Full Text Available Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, we explored the combined anti-proliferative potential of four iron chelators, namely: desferrioxamine (DFO, salicylaldehyde isonicotinoyl hydrazone (SIH, (E-N'-[1-(2-hydroxy-5-nitrophenylethyliden] isonicotinoyl hydrazone (NHAPI, and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT, plus six selected anti-neoplastic drugs. These six agents are used for breast cancer treatment and include: paclitaxel, 5-fluorouracil, doxorubicin, methotrexate, tamoxifen and 4-hydroperoxycyclophosphamide (an active metabolite of cyclophosphamide. Our quantitative chelator-drug analyses were designed according to the Chou-Talalay method for drug combination assessment. All combinations of these agents yielded concentration-dependent, anti-proliferative effects. The hydrophilic siderophore, DFO, imposed antagonism when used in combination with all six anti-tumor agents and this antagonistic effect increased with increasing dose. Conversely, synergistic interactions were observed with combinations of the lipophilic chelators, NHAPI or Dp44mT, with doxorubicin and also the combinations of SIH, NHAPI or Dp44mT with tamoxifen. The combination of Dp44mT with anti-neoplastic agents was further enhanced following formation of its redox-active iron and especially copper complexes. The most potent combinations of Dp44mT and NHAPI with tamoxifen were confirmed as synergistic using another estrogen receptor-expressing breast cancer cell line, T47D, but not estrogen receptor

  5. Quantitative analysis of the anti-proliferative activity of combinations of selected iron-chelating agents and clinically used anti-neoplastic drugs.

    Science.gov (United States)

    Potuckova, Eliska; Jansova, Hana; Machacek, Miloslav; Vavrova, Anna; Haskova, Pavlina; Tichotova, Lucie; Richardson, Vera; Kalinowski, Danuta S; Richardson, Des R; Simunek, Tomas

    2014-01-01

    Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, we explored the combined anti-proliferative potential of four iron chelators, namely: desferrioxamine (DFO), salicylaldehyde isonicotinoyl hydrazone (SIH), (E)-N'-[1-(2-hydroxy-5-nitrophenyl)ethyliden] isonicotinoyl hydrazone (NHAPI), and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), plus six selected anti-neoplastic drugs. These six agents are used for breast cancer treatment and include: paclitaxel, 5-fluorouracil, doxorubicin, methotrexate, tamoxifen and 4-hydroperoxycyclophosphamide (an active metabolite of cyclophosphamide). Our quantitative chelator-drug analyses were designed according to the Chou-Talalay method for drug combination assessment. All combinations of these agents yielded concentration-dependent, anti-proliferative effects. The hydrophilic siderophore, DFO, imposed antagonism when used in combination with all six anti-tumor agents and this antagonistic effect increased with increasing dose. Conversely, synergistic interactions were observed with combinations of the lipophilic chelators, NHAPI or Dp44mT, with doxorubicin and also the combinations of SIH, NHAPI or Dp44mT with tamoxifen. The combination of Dp44mT with anti-neoplastic agents was further enhanced following formation of its redox-active iron and especially copper complexes. The most potent combinations of Dp44mT and NHAPI with tamoxifen were confirmed as synergistic using another estrogen receptor-expressing breast cancer cell line, T47D, but not estrogen receptor-negative MDA

  6. Optimization of High-Gravity Chelated Iron Process for Removing H2S Based on Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    Luo Ying; Zhang Zhongzhe; Qi Jibing; Li Gang; Qi Guisheng; Liu Youzhi

    2015-01-01

    By using a mixture of N2 and H2S as the simulated APG (associated petroleum gas), the desulfurization experi-ment was performed in a cross-lfow rotating packed bed (RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ions (ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio (ranging from 15 to 25 L/m3) and the high gravity factor (ranging from 36 to 126) on the removal of H2S were studied by means of the Box-Behnken design (BBD) under response surface methodology (RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses (at a Fe3+ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efifciency could reach 98.81%when the H2S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the energy dispersive X-ray spectrometer (EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation.

  7. Chelation in metal intoxication

    DEFF Research Database (Denmark)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, yang;

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...

  8. Effectiveness of antioxidants in preventing oxidation of palm oil enriched with heme iron: A model for iron fortification in baked products

    OpenAIRE

    Alemán Ezcaray, Mercedes; Nuchi, C. D.; Bou Novensà, Ricard; Tres Oliver, Alba; Polo Pozo, Francisco Javier; Guardiola Ibarz, Francesc; Codony Salcedo, Rafael

    2010-01-01

    Bakery products such as biscuits, cookies, and pastries represent a good medium for iron fortification in food products, since they are consumed by a large proportion of the population at risk of developing iron deficiency anemia, mainly children. The drawback, however, is that iron fortification can promote oxidation. To assess the extent of this, palm oil added with heme iron and different antioxidants was used as a model for evaluating the oxidative stability of some bakery products, such ...

  9. Effect of antioxidants on lipid peroxidation in iron-loaded rats.

    Science.gov (United States)

    Dillard, C J; Downey, J E; Tappel, A L

    1984-02-01

    Indirect evidence has suggested that lipid peroxidation is associated with iron overload in vivo. As a measure of lipid peroxidation, pentane expired in the breath of rats loaded with an accumulated dose of either 100 mg or 186-200 mg of iron injected intraperitoneally as iron dextran was measured over a 7 to 8 week period, and the effect on pentane production of feeding antioxidant-supplemented diets was determined. By the seventh week of feeding the diets, rats fed 0.3% L-ascorbic acid produced 17% less (P = 0.03) pentane than did rats fed the basal antioxidant-deficient diet, whereas rats fed 0.004% dl-alpha-tocopherol acetate produced 92% less (P less than 0.001). After being fed the basal diet for 7 weeks, iron-loaded rats produced 76 +/- 9 pmol pentane/100 g body wt/min. When synthetic antioxidants were added to the diet at a concentration of 0.25%, the order of effectiveness in decreasing pentane production after 1 week was: N,N'-diphenyl-p-phenylenediamine greater than ethoxyquin greater than butylated hydroxyanisole greater than butylated hydroxytoluene greater than propyl gallate approximately equal to no antioxidant. After removal of either ethoxyquin or N,N'-diphenyl-p-phenylenediamine from the diets for 1 week, pentane production increased to a high level. The total amount of lipid soluble fluorophores in individual spleens of rats fed N,N'-diphenyl-p-phenylenediamine, ethoxyquin, dl-alpha- tocopherol acetate, ascorbic acid and no antioxidant were correlated significantly with the corresponding total integrated amount of pentane produced by the individual rats over the 7 to 8 week period. This study has provided some of the most direct evidence to date that lipid peroxidation is associated with iron overload in vivo. PMID:6708751

  10. Antioxidant activity of Rhizophora mangle bark.

    Science.gov (United States)

    Sánchez, Janet; Melchor, Gleiby; Martínez, Gregorio; Escobar, Arturo; Faure, Roberto

    2006-02-01

    The antioxidant activity of Rhizophora mangle bark aqueous extract and its majoritary component and high molecular weight polyphenols' fraction were studied using deoxyribose assay. The total extract and its fraction showed scavenging activity of hydroxyl radicals and hability to chelate iron ions. PMID:16436316

  11. Treatment of mild non-chemotherapy-induced iron deficiency anemia in cancer patients: comparison between oral ferrous bisglycinate chelate and ferrous sulfate.

    Science.gov (United States)

    Ferrari, Paola; Nicolini, Andrea; Manca, Maria Laura; Rossi, Giuseppe; Anselmi, Loretta; Conte, Massimo; Carpi, Angelo; Bonino, Ferruccio

    2012-09-01

    In cancer patients mild-moderate non-chemotherapy-induced iron deficiency anemia (IDA) is usually treated with oral iron salts, mostly ferrous sulfate. In this study, we compare efficacy and toxicity of oral ferrous bisglycinate chelate and ferrous sulfate in cancer patients with mild IDA. Twenty-four patients operated on for solid tumors (10 breast, 12 colorectal, 2 gastric), aged 61±10 years (range 45-75), with non-chemotherapy-induced hemoglobin (Hb) values between 10 and 12 g/dL and ferritin lower than 30 ng/mL were randomized to receive oral ferrous bisglycinate chelate, 28 mg per day for 20 days, and then 14 mg per day for 40 days (12 patients) (A group) or oral ferrous sulphate, 105 mg per day for 60 days (12 patients) (B group). Values of hemoglobin and ferritin obtained at diagnosis, 1 and 2 months from the beginning of treatment were compared. Adverse events (AEs) related to the two treatments were recorded. In the 12 patients treated with ferrous bisglycinate chelate, basal hemoglobin and ferritin values (mean±SD) were 11.6±0.8 g/dL and 16.1±8.0 ng/mL. After 2 months of treatment, they were 13.0±1.4 g/dL and 33.8±22.0 ng/mL, respectively (P=0.0003 and P=0.020). In the group treated with ferrous sulphate, hemoglobin and ferritin mean values were 11.3±0.6 g/dL and 19.0±6.4 ng/mL basally, and 12.7±0.70 g/dL and 40.8±28.1 ng/mL (P<0.0001 and P=0.017) after 2 months of treatment. AEs occurred in six cases. In all these six cases, two (17%) treated with ferrous bisglycinate chelate and four (33%) with ferrous sulphate, toxicity was grade 1. In conclusion, these data suggest that ferrous bisglycinate chelate has similar efficacy and likely lower GI toxicity than ferrous sulphate given at the conventional dose of 105 mg per day for the same time.

  12. Treatment of mild non-chemotherapy-induced iron deficiency anemia in cancer patients: comparison between oral ferrous bisglycinate chelate and ferrous sulfate.

    Science.gov (United States)

    Ferrari, Paola; Nicolini, Andrea; Manca, Maria Laura; Rossi, Giuseppe; Anselmi, Loretta; Conte, Massimo; Carpi, Angelo; Bonino, Ferruccio

    2012-09-01

    In cancer patients mild-moderate non-chemotherapy-induced iron deficiency anemia (IDA) is usually treated with oral iron salts, mostly ferrous sulfate. In this study, we compare efficacy and toxicity of oral ferrous bisglycinate chelate and ferrous sulfate in cancer patients with mild IDA. Twenty-four patients operated on for solid tumors (10 breast, 12 colorectal, 2 gastric), aged 61±10 years (range 45-75), with non-chemotherapy-induced hemoglobin (Hb) values between 10 and 12 g/dL and ferritin lower than 30 ng/mL were randomized to receive oral ferrous bisglycinate chelate, 28 mg per day for 20 days, and then 14 mg per day for 40 days (12 patients) (A group) or oral ferrous sulphate, 105 mg per day for 60 days (12 patients) (B group). Values of hemoglobin and ferritin obtained at diagnosis, 1 and 2 months from the beginning of treatment were compared. Adverse events (AEs) related to the two treatments were recorded. In the 12 patients treated with ferrous bisglycinate chelate, basal hemoglobin and ferritin values (mean±SD) were 11.6±0.8 g/dL and 16.1±8.0 ng/mL. After 2 months of treatment, they were 13.0±1.4 g/dL and 33.8±22.0 ng/mL, respectively (P=0.0003 and P=0.020). In the group treated with ferrous sulphate, hemoglobin and ferritin mean values were 11.3±0.6 g/dL and 19.0±6.4 ng/mL basally, and 12.7±0.70 g/dL and 40.8±28.1 ng/mL (Pferrous bisglycinate chelate and four (33%) with ferrous sulphate, toxicity was grade 1. In conclusion, these data suggest that ferrous bisglycinate chelate has similar efficacy and likely lower GI toxicity than ferrous sulphate given at the conventional dose of 105 mg per day for the same time. PMID:22795809

  13. Magnetic bead-based enzyme-chromogenic substrate system for ultrasensitive colorimetric immunoassay accompanying cascade reaction for enzymatic formation of squaric acid-iron(III) chelate.

    Science.gov (United States)

    Lai, Wenqiang; Tang, Dianping; Zhuang, Junyang; Chen, Guonan; Yang, Huanghao

    2014-05-20

    This work reports on a simple and feasible colorimetric immunoassay with signal amplification for sensitive determination of prostate-specific antigen (PSA, used as a model) at an ultralow concentration by using a new enzyme-chromogenic substrate system. We discovered that glucose oxidase (GOx), the enzyme broadly used in enzyme-linked immunosorbent assay (ELISA), has the ability to stimulate in situ formation of squaric acid (SQA)-iron(III) chelate. GOx-catalyzed oxidization of glucose leads to the formation of gluconic acid and hydrogen peroxide (H2O2). The latter can catalytically oxidize iron(II) to iron(III), which can rapidly (immunoassay protocol with GOx-labeled anti-PSA detection antibody can be designed for the detection of target PSA on capture antibody-functionalized magnetic immunosensing probe, monitored by recording the color or absorbance (λ = 468 nm) of the generated SQA-iron(III) chelate. The absorbance intensity shows to be dependent on the concentration of target PSA. A linear dependence between the absorbance and target PSA concentration is obtained under optimal conditions in the range from 1.0 pg mL(-1) to 30 ng mL(-1) with a detection limit (LOD) of 0.5 pg mL(-1) (0.5 ppt) estimated at the 3Sblank level. The sensitivity displays to be 3-5 orders of magnitude better than those of most commercialized human PSA ELISA kits. In addition, the developed colorimetric immunoassay was validated by assaying 12 human serum samples, receiving in good accordance with those obtained by the commercialized PSA ELISA kit. Importantly, the SQA-based immunosensing system can be further extended for the detection of other low-abundance proteins or biomarkers by controlling the target antibody.

  14. Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry

    OpenAIRE

    Muhlisin,; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-01-01

    This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw...

  15. Hypoxia-inducible factor prolyl hydroxylases as targets for neuroprotection by "antioxidant" metal chelators: From ferroptosis to stroke.

    Science.gov (United States)

    Speer, Rachel E; Karuppagounder, Saravanan S; Basso, Manuela; Sleiman, Sama F; Kumar, Amit; Brand, David; Smirnova, Natalya; Gazaryan, Irina; Khim, Soah J; Ratan, Rajiv R

    2013-09-01

    Neurologic conditions including stroke, Alzheimer disease, Parkinson disease, and Huntington disease are leading causes of death and long-term disability in the United States, and efforts to develop novel therapeutics for these conditions have historically had poor success in translating from bench to bedside. Hypoxia-inducible factor (HIF)-1α mediates a broad, evolutionarily conserved, endogenous adaptive program to hypoxia, and manipulation of components of the HIF pathway is neuroprotective in a number of human neurological diseases and experimental models. In this review, we discuss molecular components of one aspect of hypoxic adaptation in detail and provide perspective on which targets within this pathway seem to be ripest for preventing and repairing neurodegeneration. Further, we highlight the role of HIF prolyl hydroxylases as emerging targets for the salutary effects of metal chelators on ferroptosis in vitro as well in animal models of neurological diseases.

  16. Hepatic but not brain iron is rapidly chelated by deferasirox in aceruloplasminemia due to a novel gene mutation

    OpenAIRE

    Finkenstedt, Armin; Wolf, Elisabeth; Höfner, Elmar; Gasser, Bethina Isasi; Bösch, Sylvia; Bakry, Rania; Creus, Marc; Kremser, Christian; Schocke, Michael; Theurl, Milan; Moser, Patrizia; Schranz, Melanie; Bonn, Guenther; Poewe, Werner; Vogel, Wolfgang

    2010-01-01

    Background & Aims Aceruloplasminemia is a rare autosomal recessive neurodegenerative disease associated with brain and liver iron accumulation which typically presents with movement disorders, retinal degeneration, and diabetes mellitus. Ceruloplasmin is a multi-copper ferroxidase that is secreted into plasma and facilitates cellular iron export and iron binding to transferrin. Results A novel homozygous ceruloplasmin gene mutation, c.2554+1G>T, was identified as the cause of aceruloplasminem...

  17. cis-Dioxomolybdenum(VI) complexes of a new ONN chelating thiosemicarbazidato ligand; Synthesis, characterization, crystal, molecular structures and antioxidant activities

    Science.gov (United States)

    İlhan Ceylan, Berat; Deniz, Nahide Gulsah; Kahraman, Sibel; Ulkuseven, Bahri

    2015-04-01

    5-Chloro-4-methyl-2-hydroxybenzophenone S-propyl-4-phenyl-thiosemicarbazone (H2L) and its cis-dioxomolybdenum(VI) complexes, in the general formula [MoO2(L)R-OH)] (R: methyl, 1; ethyl, 2; n-propyl, 3; n-butyl, 4; n-pentyl, 5), were synthesized and characterized by micro analysis, electronic, infrared and 1H and 13C NMR spectra. The crystal structures of complexes, 1 and 3, have been solved by direct methods (SIR92) and refined to the residual indexes R1 = 0.098 and R1 = 0.052 respectively. Complexes 1 and 3 are crystallized in the triclinic space group P-1 with Z = 2. The crystal study of complex 1 showed the first example of intermolecular hydrogen bond for this type of molybdenum-thiosemicarbazone complexes. The hydrogen bond is between the hydroxyl proton of attached alcohol and an oxo oxygen (in MoO22+ unit) of another complex molecule, and its bond distance (1.767(1) Å) is shorter than from the σ-coordination bonds in complex 1. Antioxidant activities of the compounds were determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Ligand showed 23.61% DPPH radical scavenging activity at 250 mg/L concentration. Cupric Reducing Antioxidant Capacity (CUPRAC) was also evaluated and trolox-equivalent antioxidant capacity (TEAC) values were found for ligand, 1 and 3 as 0.51, 0.33 and 0.30 respectively.

  18. Iron fertilization with FeEDDHA : the fate and effectiveness of FeEDDHA chelates in soil-plant systems

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.

    2010-01-01

    Iron deficiency chlorosis is a nutritional disorder in plants which reduces crop yields both quantitatively and qualitatively, and causes large economic losses. It occurs world-wide, predominantly in plants grown on calcareous soils, as a result of a limited bioavailability of iron related to the po

  19. Discovery of an extended bundle sheath in Ricinus communis L. and its role as a temporal storage compartment for the iron chelator nicotianamine.

    Science.gov (United States)

    Rutten, T; Krüger, C; Melzer, M; Stephan, U W; Hell, R

    2003-07-01

    The extended bundle sheath (EBS) is a specialized layer of cells that enhances the lateral transport of photoassimilates within the leaf. This little-known tissue is often considered to be legume-specific. We identified an EBS in cotyledons and leaves of the non-legume Ricinus communis L. By means of cytological and immunological studies and using the localization of the iron-chelator nicotianamine as an established indicator for mass transport, we confirmed its role as a transport tissue and a temporal sink. Observations on cotyledons of Ricinus seedlings further proved that the EBS carries out these tasks from a very early stage of development onwards. This is the first time that information has been obtained on the physiological role of an EBS in a non-legume. Our results support the idea of its widespread occurrence among higher plants. PMID:14520566

  20. cis-Dioxomolybdenum(VI) complexes of a new ONN chelating thiosemicarbazidato ligand; synthesis, characterization, crystal, molecular structures and antioxidant activities.

    Science.gov (United States)

    İlhan Ceylan, Berat; Deniz, Nahide Gulsah; Kahraman, Sibel; Ulkuseven, Bahri

    2015-04-15

    5-Chloro-4-methyl-2-hydroxybenzophenone S-propyl-4-phenyl-thiosemicarbazone (H2L) and its cis-dioxomolybdenum(VI) complexes, in the general formula [MoO2(L)R-OH)] (R: methyl, 1; ethyl, 2; n-propyl, 3; n-butyl, 4; n-pentyl, 5), were synthesized and characterized by micro analysis, electronic, infrared and (1)H and (13)C NMR spectra. The crystal structures of complexes, 1 and 3, have been solved by direct methods (SIR92) and refined to the residual indexes R1=0.098 and R1=0.052 respectively. Complexes 1 and 3 are crystallized in the triclinic space group P-1 with Z=2. The crystal study of complex 1 showed the first example of intermolecular hydrogen bond for this type of molybdenum-thiosemicarbazone complexes. The hydrogen bond is between the hydroxyl proton of attached alcohol and an oxo oxygen (in MoO2(2+) unit) of another complex molecule, and its bond distance (1.767(1)Å) is shorter than from the σ-coordination bonds in complex 1. Antioxidant activities of the compounds were determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Ligand showed 23.61% DPPH radical scavenging activity at 250 mg/L concentration. Cupric Reducing Antioxidant Capacity (CUPRAC) was also evaluated and trolox-equivalent antioxidant capacity (TEAC) values were found for ligand, 1 and 3 as 0.51, 0.33 and 0.30 respectively. PMID:25681810

  1. Optimization of the Preparation Process for Iron Chelate of Tilapia Scale Collagen Peptide%罗非鱼鳞胶原蛋白肽铁螯合物制备工艺的优化

    Institute of Scientific and Technical Information of China (English)

    刘永; 叶娴; 韦寿莲

    2013-01-01

    设计四因素三水平的响应面实验进行优化罗非鱼鳞胶原蛋白肽铁螯合物的制备工艺,建立了肽铁螯合率与pH、肽铁质量比、时间、温度的数学模型.结果表明,pH、肽铁质量比、时间对肽铁螯合率影响显著.最佳制备工艺参数为:pH=5.4、温度40℃、肽铁质量比3∶1、时间41min.在该条件下,得到肽铁螯合率的验证值为90.49%,与预测值无显著差异.%According to the experimental design principle of response surface methodology,a response surface experiment with four factors and three levels was designed to optimize the preparation process of the tilapia scales collagen peptide iron chelate.A mathematical model was established to describe peptide iron chelate rate as a function of pH,peptide iron mass ratio,time and temperature.The results show that pH,peptide iron mass ratio and time have a significant effect on the peptide iron chelate rate.The optimal preparation conditions are:pH =5.4,temperature 40 ℃,the peptide iron mass ratio 3 ∶ 1,and time 41 min.Under the optimal preparation process,the practical value of peptide iron chelate rate is 90.49%,which has no significant difference from the predicted value.

  2. Alkylation of Sulfur Ligand in Cysteinate-Iron Chelates by a 1,2,4,5-Tetraoxane

    Institute of Scientific and Technical Information of China (English)

    刘鹤华; 伍贻康; 沈鑫

    2003-01-01

    Reaction of a 1,2, 4, 5-tetraoxane with cysteinate-iron in the presence of excess methyl cysteinate led to formation of sulfuralkylated methyl cysteinate in 33 % yield, illustrating a possible mechanism for tetraoxanes' antimalarial action.

  3. Effects of iron-glycine chelate on growth, carcass characteristic, liver mineral concentrations and haematological and biochemical blood parameters in broilers.

    Science.gov (United States)

    Kwiecień, M; Samolińska, W; Bujanowicz-Haraś, B

    2015-12-01

    Studies were carried out to determine the effect of additive iron-glycine chelate on the production performance, slaughter yield, mineral deposition in the liver and the metabolic blood panel in broiler chickens. A total of 250 one-day-old Ross 308 chicks were allotted into five groups with five replicates of 10 birds each. Diets were supplemented with the organic form iron (Fe-Gly at the rate of 25%, 50% or 100% of the total requirements of the elements) and inorganic Fe (FeSO4 at the rate of 50% or 100%). In the experiment, iron was added to the premix (containing no Fe) in an amount of 40 or 20 mg per kg of basal diet, in groups I and II, in the form of FeSO4 , and in an amount of 40, 20 or 10 mg per kg of basal diet, in groups III, IV and V, in the form of Fe-Gly. The study covering the period from the first to the 42nd day of breeding revealed that the production performance and slaughter yield were not dependent on the form and amount of added Fe. In the experimental groups with the addition of Fe-Gly of 20 or 10 mg/kg, there were no deaths of chickens during the whole fattening period. As a result, introducing an organic form of iron covering 50% and 25% of the birds' requirement increased the effectiveness of chicken fattening (European Efficiency Index) (p < 0.01). An organic Fe compound (40, 20 or 10 mg/kg) added to mixtures contributed to significant changes in the level of biochemical and haematological indicators in blood. The study demonstrated that an addition of Fe-Gly to mixtures for broilers can be fully effective in terms of production and health performance even if the suggested requirement for this element is 50% or 25% covered.

  4. Anti-oxidative protection against iron overload-induced liver damage in mice by Cajanus cajan (L.) Millsp. leaf extract.

    Science.gov (United States)

    Sarkar, Rhitajit; Hazra, Bibhabasu; Mandal, Nripendranath

    2013-02-01

    In view of the contribution of iron deposition in the oxidative pathologic process of liver disease, the potential of 70% methanolic extract of C. cajan leaf (CLME) towards antioxidative protection against iron-overload-induced liver damage in mice has been investigated. DPPH radical scavenging and protection of Fenton reaction induced DNA damage was conducted in vitro. Post oral administration of CLME to iron overloaded mice, the levels of antioxidant and serum enzymes, hepatic iron, serum ferritin, lipid peroxidation, and protein carbonyl and hydroxyproline contents were measured, in comparison to deferasirox treated mice. Oral treatment of the plant extract effectively lowered the elevated levels of liver iron, lipid peroxidation, protein carbonyl and hydroxyproline. There was notable increment in the dropped levels of hepatic antioxidants. The dosage of the plant extract not only made the levels of serum enzymes approach normal value, but also counteracted the overwhelmed serum ferritin level. The in vitro studies indicated potential antioxidant activity of CLME. The histopathological observations also substantiated the ameliorative function of the plant extract. Accordingly, it is suggested that Cajanus cajan leaf can be a useful herbal remedy to suppress oxidative damage caused by iron overload. PMID:23923610

  5. Accumulation and distribution of iron, cadmium, lead and nickel in cucumber plants grown in hydroponics containing two different chelated iron supplies.

    Science.gov (United States)

    Csog, Árpád; Mihucz, Victor G; Tatár, Eniko; Fodor, Ferenc; Virág, István; Majdik, Cornelia; Záray, Gyula

    2011-07-01

    Cucumber plants grown in hydroponics containing 10 μM Cd(II), Ni(II) and Pb(II), and iron supplied as Fe(III) EDTA or Fe(III) citrate in identical concentrations, were investigated by total-reflection X-ray fluorescence spectrometry with special emphasis on the determination of iron accumulation and distribution within the different plant compartments (root, stem, cotyledon and leaves). The extent of Cd, Ni and Pb accumulation and distribution were also determined. Generally, iron and heavy-metal contaminant accumulation was higher when Fe(III) citrate was used. The accumulation of nickel and lead was higher by about 20% and 100%, respectively, if the iron supply was Fe(III) citrate. The accumulation of Cd was similar. In the case of Fe(III) citrate, the total amounts of Fe taken up were similar in the control and heavy-metal-treated plants (27-31 μmol/plant). Further, the amounts of iron transported from the root towards the shoot of the control, lead- and nickel-contaminated plants were independent of the iron(III) form. Although Fe mobility could be characterized as being low, its distribution within the shoot was not significantly affected by the heavy metals investigated.

  6. Clinical monitoring and management of complications related to chelation therapy in patients with β-thalassemia.

    Science.gov (United States)

    Saliba, Antoine N; El Rassi, Fuad; Taher, Ali T

    2016-01-01

    Iron chelating agents - deferoxamine (DFO), deferiprone (DFP), and deferasirox (DFX) - are used to treat chronic iron overload in patients with β-thalassemia in an attempt to reduce morbidity and mortality related to siderosis. Each of the approved iron chelating agents has its own advantages over the others and also has its own risks, whether related to over-chelation or not. In this review, we briefly discuss the methods to monitor the efficacy of iron chelation therapy (ICT) and the evidence behind the use of each iron chelating agent. We also portray the risks and complications associated with each iron chelating agent and recommend strategies to manage adverse events. PMID:26613264

  7. Manganese-induced hydroxyl radical formation in rat striatum is not attenuated by dopamine depletion or iron chelation in vivo

    NARCIS (Netherlands)

    Sloot, WN; Korf, J; Koster, JF; DeWit, LEA; Gramsbergen, JBP

    1996-01-01

    The present studies were aimed at investigating the possible roles of dopamine (DA) and iron in production of hydroxyl radicals ((OH)-O-.) in rat striatum after Mn2+ intoxication. For this purpose, DA depletions were assessed concomitant with in vivo 2,3- and 2,5-dihydroxybenzoic acid (DHBA) formati

  8. Iron Deficiency-induced Increase of Root Branching Contributes to the Enhanced Root Ferric Chelate Reductase Activity

    Institute of Scientific and Technical Information of China (English)

    Chong-Wei Jin; Wei-Wei Chen; Zhi-Bin Meng; Shao-Jian Zheng

    2008-01-01

    In various plant species, Fe deficiency increases lateral root branching. However, whether this morphological alteration contributes to the Fe deficiency-induced physiological responses still remains to be demonstrated. In the present research, we demonstrated that the lateral root development of red clover (Trifolium pretense L.) was significantly enhanced by Fe deficient treatment, and the total lateral root number correlated well with the Fe deficiency-induced ferric chelate reductase (FCR) activity. By analyzing the results from Dasgan et al. (2002), we also found that although the two tomato genotypes line227/1 (P1) and Roza (P2) and their reciprocal F1 hybrid lines ("P1 × P2" and "P2 × P1 ") were cultured under two different lower Fe conditions (10-6 and 10-7 M FeEDDHA), their FCR activities are significantly correlated with the lateral root number. More interestingly, the -Fe chlorosis tolerant ability of these four tomato lines displays similar trends with the lateral root density. Taking these results together, it was proposed that the Fe deficiency-induced increases of the lateral root should play an important role in resistance to Fe deficiency, which may act as harnesses of a useful trait for the selection and breeding of more Fe-efficiant crops among the genotypes that have evolved a Fe deficiency-induced Fe uptake system.

  9. An Antioxidant Extract of the Insectivorous Plant Drosera burmannii Vahl. Alleviates Iron-Induced Oxidative Stress and Hepatic Injury in Mice

    OpenAIRE

    Nikhil Baban Ghate; Dipankar Chaudhuri; Abhishek Das; Sourav Panja; Nripendranath Mandal

    2015-01-01

    Free iron typically leads to the formation of excess free radicals, and additional iron deposition in the liver contributes to the oxidative pathologic processes of liver disease. Many pharmacological properties of the insectivorous plant Drosera burmannii Vahl. have been reported in previous studies; however, there is no evidence of its antioxidant or hepatoprotective potential against iron overload. The antioxidant activity of 70% methanolic extract of D. burmannii (DBME) was evaluated. DBM...

  10. Overview of chelation recommendations for thalassaemia and sickle cell disease

    Directory of Open Access Journals (Sweden)

    Banu Kaya

    2014-12-01

    Full Text Available The long term consequences of iron toxicity are mostly reversible with effective iron chelation therapy. Recommendations for use of chelation therapy in transfusion dependent thalassaemia (TDT, sickle cell disease (SCD and non transfusion dependent thalassaemia (NTDT continue to evolve as our knowledge and clinical experience increases. Improved chelation options including drug combinations and a better understanding of condition specific factors may help to improve efficiency of chelation regimens and meet the needs of patients more effectively.

  11. Chemical composition, iron bioavailability, and antioxidant activity of Kappaphycus alvarezzi (Doty).

    Science.gov (United States)

    Fayaz, Mohamed; Namitha, K K; Murthy, K N Chidambara; Swamy, M Mahadeva; Sarada, R; Khanam, Salma; Subbarao, P V; Ravishankar, G A

    2005-02-01

    Kappaphycus alvarezzi, an edible seaweed from the west coast of India, was analyzed for its chemical composition. It was found that K. alvarezzi is rich in protein (16.24% w/w) and contains a high amount of fiber (29.40% w/w) and carbohydrates (27.4% w/w). K. alvarezzi showed vitamin A activity of 865 mug retinal equivalents/100 g of sample. It contained a higher quantity of unsaturated fatty acids (44.50% of the total), in which relative percentage of oleic acid was 11%, cis-heptadecanoic acid 13.50%, and linoleic acid 2.3% and 37.0% of saturated fatty acids (mainly heptadecanoic acid). K. alvarezziwas also found to be good source of minerals, viz 0.16% of calcium, 0.033% of iron, and 0.016% of zinc, which are essential for various vital biological activities. Bioavailability of iron by in vitro methods showed a higher efficiency in intestinal conditions than in stomach conditions. Ascorbic acid influenced higher bioavailability of iron. Successive extracts of n-hexane, acetone, ethyl acetate, ethanol, and direct extractables of chloroform/methanol (1:1 and 2:1) were screened for antioxidant activity using a beta-carotene linoleic acid model system (B-CLAMS), DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) model system and hydroxyl radical scavenging activity. The chloroform/methanol (2:1) extract has shown 82.5% scavenging activity at 1000 ppm. Acetone fraction extracts at the 1000 ppm level showed 63.31% antioxidant activity in beta-carotene linoleic acid system. The acetone extract showed 46.04% scavenging activity at 1000 ppm concentration. In the case of hydroxyl radical scavenging activity, all the extracts showed better activity at the concentrations of 25 and 50 ppm, where at the 50 ppm level ethyl acetate extract showed 76.0%, acetone 75.12%, and hexane 71.15% activity, respectively. Results of this study suggest the utility of K. alvarezzi (Eucheuma) for various nutritional products, including antioxidant for use as health food or nutraceutical

  12. Tratamento da anemia ferropriva com ferro quelato glicinato e crescimento de crianças na primeira infância Treatment of iron deficiency anemia with iron bis-glycinate chelate and growth of young children

    Directory of Open Access Journals (Sweden)

    Luciana Cisoto Ribeiro

    2008-10-01

    Full Text Available OBJETIVO: Avaliar a resposta à suplementação diária com ferro quelato glicinato e seu impacto sobre o crescimento linear. MÉTODOS: Realizou-se um estudo prospectivo com 790 crianças, de 6 a 36 meses, que freqüentavam creches municipais de São Paulo no período de 1999 a 2003. Ao início e ao final do estudo a hemoglobina, o peso corporal e a estatura/comprimento foram coletados. Utilizou-se suplemento contendo ferro quelato glicinato em gotas na dose de 5mg Fe elementar/kg peso/dia, administrado na própria instituição pelo profissional de saúde da creche, por um período de 12 semanas. RESULTADOS: A suplementação resultou em um significante e positivo efeito sobre os níveis de hemoglobina. A resposta ao tratamento foi positiva em 85,3% das crianças, com um aumento médio de 1,6g/dL nos valores de hemoglobina (pOBJECTIVE: The objective of this study was to evaluate response to daily supplementation with iron bis-glycinate chelate and its impact on linear growth. METHODS: A prospective study was done with 790 children aging from 6 to 36 months who attended daycare in São Paulo from 1999 to 2003. Hemoglobin levels, body weight and height/length were determined at the beginning and end of the study. Liquid iron bis-glycinate chelate was administered in a dosage of 5mg of elemental iron/kg of body weight/day given by the health provider of the daycare facility for a period of 12 weeks. RESULTS: Supplementation resulted in a significant, positive effect on the hemoglobin levels of 85.3% of the children with a mean increase of 1.6g/dL (p<0.001. In children aging from 25 to 36 months and in those with lower hemoglobin levels at the beginning of supplementation, there was a significantly higher increase. No gastrointestinal problem or intolerance to the supplement was observed during the intervention period. Supplementation also had an impact on growth and on the height-for-age indicator (z-score in children older than 12 months but

  13. Chelating bis-N-heterocyclic carbene complexes of iron(ii) containing bipyridyl ligands as catalyst precursors for oxidation of alcohols.

    Science.gov (United States)

    Pinto, Mara F; Cardoso, Bernardo de P; Barroso, Sónia; Martins, Ana M; Royo, Beatriz

    2016-09-14

    Chelating bis-N-heterocyclic carbene (bis-NHC) complexes of iron(ii) containing pyridyl ligands have been prepared by the reaction of [FeCl2L] [L = bipy (1), phen (2)] with [LiN(SiMe3)2] and a bis(imidazolium) salt. The [Fe(bis-NHC)L(I)2] complexes were active pre-catalysts in the oxidation of 1-phenylethanol with tert-butyl hydroperoxide in neat conditions, affording a quantitative yield of acetophenone in 4.5 h. The catalyst could be reused up to six cycles giving a turnover number (TON) of 1500. Various secondary alcohols, both aromatic and aliphatic were selectivity oxidised to the corresponding ketones in excellent yields. Compound 1 is stable in acetonitrile solution for ca. 4 h, although after 16 h, it evolves to a mixture of [Fe(bis-NHC)(bipy)2]I2 (3), [Fe(bipy)3](2+) and bis-imidazolium salt. The molecular structure of 3 has been determined by X-ray diffraction studies. PMID:27506414

  14. Preparation and antioxidant activity evaluation of cod skin peptides chelated calcium%鳕鱼皮复合肽螯合钙的制备及抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    黄薇; 邓尚贵; 唐艳; 李淑芳; 孔巧香

    2012-01-01

    This paper focused on the preparation of cod skin protein chelating Ca^2+ by compound enzymolysis method, and studied the antioxidation function of the chelate. The results showed that the optimal chelation reaction between hydrolysates and CaCl2 conducted for 20 min at 25 ℃ and pH 7.0 with a calcium/peptide mass ratio of 0.3/3, yielded 58.85% of Ca^2+ chelating rate. The chelated products exhibited inhibitory effects on hydroxyl radical and super oxide anion radical.%利用木瓜蛋白酶与风味酶组合成的复合酶对鳕鱼皮蛋白进行酶解,制得酶解液,以氯化钙为钙源,与多肽酶解液反应制备多肽螯合钙,并对其抗氧化性进行了研究。结果表明,制备多肽螯合钙的最佳条件是:氯化钙与多肽的质量比为0.3:3,pH值为7.0,反应温度为25℃,反应时间为20min,在此条件下钙离子的螯合率为58.85%,产物对羟自由基(·OH)和超氧阴离子自由基(O2^-·)均有较强的清除作用。

  15. Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry.

    Science.gov (United States)

    Muhlisin; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-05-01

    This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat. PMID:26954148

  16. Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry.

    Science.gov (United States)

    Muhlisin; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-05-01

    This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat.

  17. Role of chelates in treatment of cancer

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2007-01-01

    Full Text Available Chelates are used in cancer as cytotoxic agent, as radioactive agent in imaging studies and in radioimmunotherapy. Various chelates based on ruthenium, copper, zinc, organocobalt, gold, platinum, palladium, cobalt, nickel and iron are reported as cytotoxic agent. Monoclonal antibodies labeled with radioactive metals such as yttrium-90, indium-111 and iodine-131 are used in radioimmunotherapy. This review is an attempt to compile the use of chelates as cytotoxic drugs and in radioimmunotherapy.

  18. Models of the iron-only hydrogenase: a comparison of chelate and bridge isomers of Fe2(CO)4{Ph2PN(R)PPh2}(μ-pdt) as proton-reduction catalysts.

    Science.gov (United States)

    Ghosh, Shishir; Hogarth, Graeme; Hollingsworth, Nathan; Holt, Katherine B; Richards, Idris; Richmond, Michael G; Sanchez, Ben E; Unwin, David

    2013-05-21

    Reactions of Fe2(CO)6(μ-pdt) (pdt = SCH2CH2CH2S) with aminodiphosphines Ph2PN(R)PPh2 (R = allyl, (i)Pr, (i)Bu, p-tolyl, H) have been carried out under different conditions. At room temperature in MeCN with added Me3NO·2H2O, dibasal chelate complexes Fe2(CO)4{κ(2)-Ph2PN(R)PPh2}(μ-pdt) are formed, while in refluxing toluene bridge isomers Fe2(CO)4{μ-Ph2PN(R)PPh2}(μ-pdt) are the major products. Separate studies have shown that chelate complexes convert to the bridge isomers at higher temperatures. Two pairs of bridge and chelate isomers (R = allyl, (i)Pr) have been crystallographically characterised together with Fe2(CO)4{μ-Ph2PN(H)PPh2}(μ-pdt). Chelate complexes adopt the dibasal diphosphine arrangement in the solid state and exhibit very small P-Fe-P bite-angles, while the bridge complexes adopt the expected cisoid dibasal geometry. Density functional calculations have been carried out on the chelate and bridge isomers of the model compound Fe2(CO)4{Ph2PN(Me)PPh2}(μ-pdt) and reveal that the bridge isomer is thermodynamically favourable relative to the chelate isomers that are isoenergetic. The HOMO in each of the three isomers exhibits significant metal-metal bonding character, supporting a site-specific protonation of the iron-iron bond upon treatment with acid. Addition of HBF4·Et2O to the Fe2(CO)4{κ(2)-Ph2PN(allyl)PPh2}(μ-pdt) results in the clean formation of the corresponding dibasal hydride complex [Fe2(CO)4{κ(2)-Ph2PN(allyl)PPh2}(μ-H)(μ-pdt)][BF4], with spectroscopic measurements revealing the intermediate formation of a basal-apical isomer. A crystallographic study reveals that there are only very small metric changes upon protonation. In contrast, the bridge isomers react more slowly to form unstable species that cannot be isolated. Electrochemical and electrocatalysis studies have been carried out on the isomers of Fe2(CO)4{Ph2PN(allyl)PPh2}(μ-pdt). Electron accession is predicted to occur at an orbital that is anti-bonding with respect to

  19. Antioxidants

    Science.gov (United States)

    Antioxidants are man-made or natural substances that may prevent or delay some types of cell damage. Antioxidants are found in many foods, including fruits and ... are also available as dietary supplements. Examples of antioxidants include Beta-carotene Lutein Lycopene Selenium Vitamin A ...

  20. Enhanced antioxidation and electromagnetic properties of Co-coated flaky carbonyl iron particles prepared by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yingying, E-mail: zyzlchappy1989@163.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Zhou, Wancheng [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Li, Rong [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); No. 603 Faculty, Xi’an Institute of High Technology, Xi’an 710025 (China); Mu, Yang; Qing, Yuchang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

    2015-07-15

    Highlights: • Co-coated carbonyl iron particles were prepared by electroless plating method. • The obvious weight gain of carbonyl iron was deferred to 400 °C after Co-coated. • The permeability of the Co-coated particle composite kept almost invariable. • Co-coated carbonyl iron composite reserves a better absorption after heat treatment. - Abstract: Co was successfully coated on the surface of flaky carbonyl iron particles using an electroless plating method. The morphologies, composition, as well as magnetic, antioxidation and electromagnetic properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), vibrating sample magnetometer (VSM), thermogravimetric (TG) and microwave network analyzer. TG curve shows that the obvious weight gain of carbonyl iron was deferred from 300 to 400 °C after Co-coated. In contrast to raw carbonyl iron, the Co-coated carbonyl iron shows better stability on electromagnetic properties after 300 °C heat treatment for 10 h, demonstrating that the Co coating can act as the protection of carbonyl iron.

  1. Purification and antioxidant activities of baicalin isolated from the root of huangqin (Scutellaria baicalensis gcorsi)

    OpenAIRE

    Peng-fei, Liu; Fu-gen, Han; Bin-bin, Duan; Tian-sheng, Deng; Xiang-lin, Hou; Ming-qin, Zhao

    2012-01-01

    Baicalin is a flavonoid from the root of huangqin (Scutellaria baicalensis gcorsi, a kind of Traditional Chinese Medicine and food condiment) with two pro phenolic hydroxyls. In this manuscript, high purity of baicalin (95.5 %) was isolated from the root of huangqin and its antioxidant activities were investigated. The antioxidant properties of baicalin were evaluated by scavenging of the diphenylpicrylhydrazyl radical (DPPH), reducing power, and iron-chelating assays, compared to ascorbic ac...

  2. N-acetylcysteine protects rats with chronic renal failure from gadolinium-chelate nephrotoxicity.

    Directory of Open Access Journals (Sweden)

    Leonardo Victor Barbosa Pereira

    Full Text Available The aim of this study was to evaluate the effect of Gd-chelate on renal function, iron parameters and oxidative stress in rats with CRF and a possible protective effect of the antioxidant N-Acetylcysteine (NAC. Male Wistar rats were submitted to 5/6 nephrectomy (Nx to induced CRF. An ionic-cyclic Gd (Gadoterate Meglumine was administrated (1.5 mM/KgBW, intravenously 21 days after Nx. Clearance studies were performed in 4 groups of anesthetized animals 48 hours following Gd- chelate administration: 1--Nx (n = 7; 2--Nx+NAC (n = 6; 3--Nx+Gd (n = 7; 4--Nx+NAC+Gd (4.8 g/L in drinking water, initiated 2 days before Gd-chelate administration and maintained during 4 days (n = 6. This group was compared with a control. We measured glomerular filtration rate, GFR (inulin clearance, ml/min/kg BW, proteinuria (mg/24 hs, serum iron (µg/dL; serum ferritin (ng/mL; transferrin saturation (%, TIBC (µg/dL and TBARS (nmles/ml. Normal rats treated with the same dose of Gd-chelate presented similar GFR and proteinuria when compared with normal controls, indicating that at this dose Gd-chelate is not nephrotoxic to normal rats. Gd-chelate administration to Nx-rats results in a decrease of GFR and increased proteinuria associated with a decrease in TIBC, elevation of ferritin serum levels, transferrin oversaturation and plasmatic TBARS compared with Nx-rats. The prophylactic treatment with NAC reversed the decrease in GFR and the increase in proteinuria and all alterations in iron parameters and TBARS induced by Gd-chelate. NAC administration to Nx rat did not modify the inulin clearance and iron kinetics, indicating that the ameliorating effect of NAC was specific to Gd-chelate. These results suggest that NAC can prevent Gd-chelate nephrotoxicity in patients with chronic renal failure.

  3. Overview of current chelation practices

    Directory of Open Access Journals (Sweden)

    Y. Aydinok

    2011-12-01

    Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

  4. Novel double prodrugs of the iron chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED): Synthesis, characterization, and investigation of activation by chemical hydrolysis and oxidation.

    Science.gov (United States)

    Thiele, Nikki A; Abboud, Khalil A; Sloan, Kenneth B

    2016-08-01

    The development of iron chelators suitable for the chronic treatment of diseases where iron accumulation and subsequent oxidative stress are implicated in disease pathogenesis is an active area of research. The clinical use of the strong chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) and its alkyl ester prodrugs has been hindered by poor oral bioavailability and lack of conversion to the parent chelator, respectively. Here, we present novel double prodrugs of HBED that have the carboxylate and phenolate donors of HBED masked with carboxylate esters and boronic acids/esters, respectively. These double prodrugs were successfully synthesized as free bases (7a-f) or as dimesylate salts (8a-c,e), and were characterized by (1)H, (13)C, and (11)B NMR; MP; MS; and elemental analysis. The crystal structure of 8a was solved. Three of the double prodrugs (8a-c) were selected for further investigation into their abilities to convert to HBED by stepwise hydrolysis and H2O2 oxidation. The serial hydrolysis of the pinacol and methyl esters of N,N'-bis(2-boronic acid pinacol ester benzyl)ethylenediamine-N,N'-diacetic acid methyl ester dimesylate (8a) was verified by LC-MS. The macro half-lives for the hydrolyses of 8a-c, measured by UV, ranged from 3.8 to 26.3 h at 37 °C in pH 7.5 phosphate buffer containing 50% MeOH. 9, the product of hydrolysis of 8a-c and the intermediate in the conversion pathway, showed little-to-no affinity for iron or copper in UV competition experiments. 9 underwent a serial oxidative deboronation by H2O2 in N-methylmorpholine buffer to generate HBED (k = 10.3 M(-1) min(-1)). The requirement of this second step, oxidation, before conversion to the active chelator is complete may confer site specificity when only localized iron chelation is needed. Overall, these results provide proof of principle for the activation of the double prodrugs by chemical hydrolysis and H2O2 oxidation, and merit further investigation into the

  5. Unsymmetrical Chelation of N-Thioether-Functionalized Bis(diphenylphosphino)amine-Type Ligands and Substituent Effects on the Nuclearity of Iron(II) Complexes: Structures, Magnetism, and Bonding.

    Science.gov (United States)

    Fliedel, Christophe; Rosa, Vitor; Falceto, Andrés; Rosa, Patrick; Alvarez, Santiago; Braunstein, Pierre

    2015-07-01

    Starting from the short-bite ligands N-thioether-functionalized bis(diphenylphosphino)amine-type (Ph2P)2N(CH2)3SMe (1) and (Ph2P)2N(p-C6H4)SMe (2), the Fe(II) complexes [FeCl2(1)]n (3), [FeCl2(2)]2 (4), [Fe(OAc)(1)2]PF6 (5), and [Fe(OAc)(2)2]PF6 (6) were synthesized and characterized by Fourier transform IR, mass spectrometry, elemental analysis, and also by X-ray diffraction for 3, 4, and 6. Complex 3 is a coordination polymer in which 1 acts as a P,P-pseudochelate and a (P,P),S-bridge, whereas 4 has a chlorido-bridged dinuclear structure in which 2 acts only as a P,P-pseudochelate. Since these complexes were obtained under strictly similar synthetic and crystallization conditions, these unexpected differences were ascribed to the different spacer between the nitrogen atom and the −SMe group. In both compounds, one Fe–P bond was found to be unusually long, and a theoretical analysis was performed to unravel the electronic or steric reasons for this difference. Density functional theory calculations were performed for a set of complexes of general formula [FeCl2(SR2){R21PN(R2)P′R23}] (R = H, Me; R1, R2, and R3 = H, Me, Ph), to understand the reasons for the significant deviation of the iron coordination sphere away from tetrahedral as well as from trigonal bipyramidal and the varying degree of unsymmetry of the two Fe–P bonds involving pseudochelating PN(R)P ligands. Electronic factors nicely explain the observed structures, and steric reasons were further ruled out by the structural analysis in the solid-state of the bis-chelated complex 6, which displays usual and equivalent Fe–P bond lengths. Magnetic susceptibility studies were performed to examine how the structural differences between 3 and 4 would affect the interactions between the iron centers, and it was concluded that 3 behaves as an isolated high-spin Fe(II) mononuclear complex, while significant intra- and intermolecular ferromagnetic interactions were evidenced for 4 at low temperatures

  6. Lipid peroxidation, antioxidant enzymes and glutathione levels in human erythrocytes exposed to colloidal iron hydroxide in vitro

    Directory of Open Access Journals (Sweden)

    Ferreira A.L.A.

    1999-01-01

    Full Text Available The free form of the iron ion is one of the strongest oxidizing agents in the cellular environment. The effect of iron at different concentrations (0, 1, 5, 10, 50, and 100 µM Fe3+ on the normal human red blood cell (RBC antioxidant system was evaluated in vitro by measuring total (GSH and oxidized (GSSG glutathione levels, and superoxide dismutase (SOD, catalase, glutathione peroxidase (GSH-Px and reductase (GSH-Rd activities. Membrane lipid peroxidation was assessed by measuring thiobarbituric acid reactive substance (TBARS. The RBC were incubated with colloidal iron hydroxide and phosphate-buffered saline, pH 7.45, at 37oC, for 60 min. For each assay, the results for the control group were: a GSH = 3.52 ± 0.27 µM/g Hb; b GSSG = 0.17 ± 0.03 µM/g Hb; c GSH-Px = 19.60 ± 1.96 IU/g Hb; d GSH-Rd = 3.13 ± 0.17 IU/g Hb; e catalase = 394.9 ± 22.8 IU/g Hb; f SOD = 5981 ± 375 IU/g Hb. The addition of 1 to 100 µM Fe3+ had no effect on the parameters analyzed. No change in TBARS levels was detected at any of the iron concentrations studied. Oxidative stress, measured by GSH kinetics over time, occurs when the RBC are incubated with colloidal iron hydroxide at concentrations higher than 10 µM of Fe3+. Overall, these results show that the intact human RBC is prone to oxidative stress when exposed to Fe3+ and that the RBC has a potent antioxidant system that can minimize the potential damage caused by acute exposure to a colloidal iron hydroxide in vitro.

  7. Relation between iron metabolism and antioxidants enzymes and δ-ALA-D activity in rats experimentally infected by Fasciola hepatica.

    Science.gov (United States)

    Bottari, Nathieli B; Mendes, Ricardo E; Baldissera, Matheus D; Bochi, Guilherme V; Moresco, Rafael N; Leal, Marta L R; Morsch, Vera M; Schetinger, Maria R C; Christ, Ricardo; Gheller, Larissa; Marques, Éder J; Da Silva, Aleksandro S

    2016-06-01

    The aim of this study was to evaluate the iron metabolism in serum, as well as antioxidant enzymes, in addition to the Delta-Aminolevulinic Acid Dehydratase (δ-ALA-D) activity in the liver of rats experimentally infected by Fasciola hepatica. Thirty male adult rats (Wistar) specific pathogen free were divided into four groups: two uninfected group (CTRL 1 and CTRL 2) with five animals each and two infected groups (INF 1 and INF 2) with 10 animals each. Infection was performed orally with 20 metacercariae at day 1. On day 15 (CTRL 1 and INF 1 groups) and 87 PI (CTRL 2 and INF 2 groups) blood and bone marrow were collected and the animals were subsequently euthanized for liver sampling. Blood was allocated in tubes without anticoagulant for serum acquisition to measure iron, transferrin and unsaturated iron binding capacity (UIBC). δ-ALA-D, superoxide dismutase (SOD), and catalase (CAT) activities were measured in the liver. A decrease in iron, transferrin and UIBC levels was observed in all infected animals compared to control groups (P < 0.05). Furthermore, iron accumulation was observed in bone marrow of infected mice. Infected animals showed an increase in δ-ALA-D activity at 87 post-infection (PI) (INF 2) as well as in SOD activity at days 15 (INF 1) and 87 PI (INF 2). On the other hand, CAT activity was reduced in rats infected by F. hepatica during acute and chronic phase of fasciolosis (INF 1 and INF 2 groups), when moderate (acute) and severe necrosis in the liver histopathology were observed. These results may suggest that oxidative damage to tissues along with antioxidant mechanisms might have taken part in fasciolosis pathogenesis and are also involved in iron deficiency associated to changes in δ-ALA-D activity during chronic phase of disease. PMID:26995536

  8. Phenolipids as antioxidants in emulsified systems

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Bayrasy, Christelle; Laguerre, Mickäel;

    Lipid oxidation is a major issue in foods containing LC PUFA and substantial efforts have been made to protect lipids against oxidation. Recent studies carried out with phenolipids (lipophilized phenolics) in emulsified systems have shown that increased lipophilicity did not necessarily lead to an...... antioxidant effect has been shown to be influenced by the specific phenolic compound and the type of emulsion. The overall aim for our work was to evaluate phenolipids with different lipophilicity as antioxidants in emulsified food. In the study presented here caffeic, ferulic and coumaric acid were selected...... along with their corresponding alkyl esters (C4-C20). The methods used to evaluate the antioxidative effect of the different phenolipids were the CAT assay (o/w emulsion), antioxidant assays (DPPH, Iron chelating and reducing power) and partitioning studies. Moreover, the results from the CAT assay on...

  9. Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial

    OpenAIRE

    Duque, Ximena; Martinez, Homero; Vilchis-Gil, Jenny; Mendoza, Eugenia; Flores-Hernández, Sergio; Morán, Segundo; Navarro, Fabiola; Roque-Evangelista, Victoria; Serrano, Anayeli; Mera, Robertino M.

    2014-01-01

    Background Iron deficiency is one of the most common nutritional deficiencies worldwide. It is more prevalent when iron requirements are increased during pregnancy and during growth spurts of infancy and adolescence. The last stage in the process of iron depletion is characterized by a decrease in hemoglobin concentration, resulting in iron deficiency anemia. Iron deficiency, even before it is clinically identified as anemia, compromises the immune response, physical capacity for work, and in...

  10. Effects of methionine chelate- or yeast proteinate-based supplement of copper, iron, manganese and zinc on broiler growth performance, their distribution in the tibia and excretion into the environment.

    Science.gov (United States)

    Singh, Abhay Kumar; Ghosh, Tapan Kumar; Haldar, Sudipto

    2015-04-01

    A straight-run flock of 1-day-old Cobb 400 chicks (n = 432) was distributed into four treatment groups (9 replicate pens in each group, 12 birds in a pen) for a 38-day feeding trial evaluating the effects of a methionine chelate (Met-TM)- or a yeast proteinate (Yeast-TM)-based supplement of copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) on growth performance, bone criteria and some metabolic indices in commercial broiler chickens. The diets were either not supplemented with any trace elements at all (negative control, NC) or supplemented with an inorganic (sulphate) trace element premix (inorganic TM (ITM), 1 g/kg feed), the Met-TM (1 g/kg feed) and the Yeast-TM (0.5 g/kg feed). Body weight, feed conversion ratio and dressed meat yield at 38 days were better in the Yeast-TM-supplemented group as compared with the NC, ITM and Met-TM groups (p chelates or yeast proteinate forms of Cu, Fe, Mn and Zn improved body weight and feed conversion ratio (FCR) and markedly reduced excretion of the said trace elements. The study revealed that it may be possible to improve broiler performance and reduce excretion of critical trace elements into the environment by complete replacement of inorganic trace minerals from their dietary regime and replacing the same with methionine chelate or yeast proteinate forms.

  11. LABILE IRON IN CELLS AND BODY FLUIDS . Physiology, Pathology and Pharmacology

    Directory of Open Access Journals (Sweden)

    Zvi Ioav Cabantchik

    2014-03-01

    Full Text Available In living systems iron appears predominantly associated with proteins, but can also be detected in forms referred as labile iron, which denotes the combined redox properties of iron and its amenability to exchange between ligands, including chelators. The labile cell iron (LCI composition varies with metal concentration and substances with chelating groups but also with pH and the redox potential. Although physiologically in the lower µM range, LCI plays a key role in cell iron economy as cross-roads of metabolic pathways. LCI levels are continually regulated by an iron-responsive machinery that balances iron uptake versus deposition into ferritin. However, LCI rises aberrantly in some cell types due to faulty cell utilization pathways or infiltration by pathological iron forms that are found in hemosiderotic plasma. As LCI attains pathological levels, it can catalyze reactive O species (ROS formation that, at particular threshold, can surpass cellular anti-oxidant capacities and seriously damage its constituents. While in normal plasma and interstitial fluids, virtually all iron is securely carried by circulating transferrin (that renders iron essentially non-labile, in systemic iron overload (IO, the total plasma iron binding capacity is often surpassed by a massive iron influx from hyperabsorptive gut or from erythrocyte overburdened spleen and/or liver. As plasma transferrin approaches iron saturation, labile plasma iron (LPI emerges in forms that can infiltrate cells by unregulated routes and raise LCI to toxic levels. Despite the limited knowledge available on LPI speciation in different types and degrees of iron overload, LPI measurements can be and are in fact used for identifying systemic IO and for initiating/adjusting chelation regimens to attain full-day LPI protection. A recent application of labile iron assay is the detection of labile components in iv iron formulations per se as well as in plasma (LPI following parenteral iron

  12. Coenzyme Q10 Supplementation Prevents Iron Overload While Improving Glycaemic Control and Antioxidant Protection in Insulin-Resistant Psammomys obesus.

    Science.gov (United States)

    Lazourgui, Mohamed Amine; El-Aoufi, Salima; Labsi, Moussa; Maouche, Boubekeur

    2016-09-01

    This study investigated the anti-diabetic preventive activity of coenzyme Q10 (CoQ10) in a murine model of diet-induced insulin resistance (IR), Psammomys obesus (Po). IR was induced by feeding a standard laboratory diet (SD). CoQ10 oil suspension was orally administered at 10 mg/kg body weight (BW)/day along with SD for 9 months. Anthropometric parameters, namely, total body weight gain (BWG) and the relative weight of white adipose tissue (WAT) were determined. Blood glucose, insulin, quantitative insulin sensitivity check index (QUICKI), total antioxidant status (TAS), iron, malondialdehyde (MDA) and nitrite (NO2 (-)) were evaluated. NO2 (-) level was also assessed in peripheral blood mononuclear cells (PBMCs) culture supernatants. Our results show that CoQ10 supplementation significantly improved blood glucose, insulin, QUICKI, TAS, iron and MDA, but influenced neither NO2 (-) levels nor the anthropometric parameters. These findings support the hypothesis that CoQ10 would exert an anti-diabetic activity by improving both glycaemic control and antioxidant protection. The most marked effect of CoQ10 observed in this study concerns the regulation of iron levels, which may carry significant preventive importance. PMID:26779622

  13. Trivalent Iron Chelator with Flavone Moiety: Synthesis and Pharmacological Properties%含黄酮的三价铁配合物合成及其药理性质

    Institute of Scientific and Technical Information of China (English)

    Emel Yildiz; Sadet Karabulut; Neslihan S.Pinar; Yusuf Karatas; Figen Doran

    2010-01-01

    3,3,4,7-四羟基黄酮与1,3-二环己基碳二亚胺在4-二甲胺吡啶存在下反应,得到2,2-双(3,3,4,7-四羟基黄酮)1,3-二环已基碳二亚胺.三价金属离子与上述合成得到的配体螯合.对此四面体结构的双核Fe(Ⅲ)配合物的血液学及病理学数据进行了讨论,同时研究了合成的配体作为螯合剂清除鼠肝胰组织中超载的铁的能力.结果表明作为口服药其作为双齿配体的螫合能力与市售用于治疗地中海贫血的药物"去铁敏"相近.%2,2-bis(3,3,4,7-tetra hydroxyflavone) 1,3-dicyclohexyl carbamine, 3,3,4,7-tetra hydroxyflavone was obtained by the reaction of 3,3,4,7-tetra hydroxyflavone with 1,3-dicyclohexyl carbodiimid in presence of 4-dimethyl amino pyridine. The above obtained ligand can chelate with trivalent metal ion. Hematologic and pathologic data of the dinuclear iron complex with tetrahedral geometry were discussed. The ability of the synthesized ligand as a chelator to remove overloaded iron from rat liver and spleen tissues was studied. The results show that the chelate effect of the ligand as the bidentate is near that of desferrioxamine available in market in oral applications for the treatment of ?thalassemia.

  14. Antioxidant potential of water hyacinth (Eichornia crassipes): In vitro antioxidant activity and phenolic composition

    DEFF Research Database (Denmark)

    Surendraraj, Alagarsamy; Farvin, Sabeena; Anandan, R.

    2011-01-01

    activity, reducing power and prevention of oxidation in a liposome model system) and its effectiveness in retarding lipid peroxidation in fish oil by accelerated stability test. Significant differences were observed in total and individual phenolic content and antioxidant activities of extracts from......The aims of the present study were (a) to extract and quantify the main phenolic acids and tocopherols from the petiole, leaf and flowers of Eichornia crassipes, (b) to evaluate the antioxidant capacity of the extracts in four in vitro systems (DPPH radical scavenging ability, iron chelating...... the highest total phenolic content, were found to have high DPPH radical scavenging activity and reducing power. Ethanolic extracts of leaf were found to have high Fe2+ chelating activity and inhibited lipid peroxidation in liposomes and fish oil. Our results demonstrate that E. crassipes, an underutilized...

  15. Iron-ascorbate-mediated lipid peroxidation causes epigenetic changes in the antioxidant defense in intestinal epithelial cells: impact on inflammation.

    Directory of Open Access Journals (Sweden)

    Sabrina Yara

    Full Text Available INTRODUCTION: The gastrointestinal tract is frequently exposed to noxious stimuli that may cause oxidative stress, inflammation and injury. Intraluminal pro-oxidants from ingested nutrients especially iron salts and ascorbic acid frequently consumed together, can lead to catalytic formation of oxygen-derived free radicals that ultimately overwhelm the cellular antioxidant defense and lead to cell damage. HYPOTHESIS: Since the mechanisms remain sketchy, efforts have been exerted to evaluate the role of epigenetics in modulating components of endogenous enzymatic antioxidants in the intestine. To this end, Caco-2/15 cells were exposed to the iron-ascorbate oxygen radical-generating system. RESULTS: Fe/Asc induced a significant increase in lipid peroxidation as reflected by the elevated formation of malondialdehyde along with the alteration of antioxidant defense as evidenced by raised superoxide dismutase 2 (SOD2 and diminished glutathione peroxidase (GPx activities and genes. Consequently, there was an up-regulation of inflammatory processes illustrated by the activation of NF-κB transcription factor, the higher production of interleukin-6 and cycloxygenase-2 as well as the decrease of IκB. Assessment of promoter's methylation revealed decreased levels for SOD2 and increased degree for GPx2. On the other hand, pre-incubation of Caco-2/15 cells with 5-Aza-2'-deoxycytidine, a demethylating agent, or Trolox antioxidant normalized the activities of SOD2 and GPx, reduced lipid peroxidation and prevented inflammation. CONCLUSION: Redox and inflammatory modifications in response to Fe/Asc -mediated lipid peroxidation may implicate epigenetic methylation.

  16. N,N',N"-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane (Deofix) - a high-affinity, high-specificity chelator for first transition series metal cations with significant deodorant, antimicrobial, and antioxidant activity.

    Science.gov (United States)

    Laden, Karl; Zaklad, Haim; Simhon, Elliot D; Klein, Joseph Y; Cyjon, Rosa L; Winchell, Harry S

    2003-01-01

    Deofix, N,N',N"-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane, is a high-affinity, high-specificity chelator for first transition series cations such as iron, zinc, manganese, and copper. A 1% solution in 50% ethanol was found to be significantly better at reducing underarm malodor than a solution of 0.3% Triclosan in 50% ethanol. Compared to a 50% alcohol control, Deofix was found to produce a significant reduction in malodor for at least 48 hours. Deofix appears to work by reducing the concentration of first transition series metal ions below the levels needed for microbial cell reproduction and by inhibiting oxidative processes by interfering with catalytic formation of free radicals. Deofix has very low levels of toxicity when measured via a number of screening techniques.

  17. Iron

    Science.gov (United States)

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  18. Exogenous Nitric Oxide Alleviated the Inhibition of Photosynthesis and Antioxidant Enzyme Activities in Iron-Deficient Chinese Cabbage(Brassica chinensis L.)

    Institute of Scientific and Technical Information of China (English)

    DING Fei; WANG Xiu-feng; SHI Qing-hua; WANG Mei-ling; YANG Feng-juan; GAO Qing-hai

    2008-01-01

    The effects of exogenous nitric oxide(NO)on plant growth,chlorophyll contents,photosynthetic and chlorophyll fluorescence parameters as well as lipid peroxidation and activities of antioxidant enzymes were investigated in Chinese cabbage plants exposed to iron(Fe)deficiency.Iron deficiency led to serious chlorosis in Chinese cabbage leaves,and resulted in significant decrease in plant growth,photosynthetic pigments,net photosynthetic rate,Fv/Fm,ΦPsⅡand activities of antioxidant enzymes,and increase in lipid peroxidation.While treatment with SNP,a NO donor,it could revert the iron deficiency symptoms,increased photosynthetic rate as well as activities of antioxidant enzymes,and protected membrane from lipid peroxidation,as a result,the growth inhibition of Chinese cabbage by Fe deficiency was alleviated.

  19. Helicobacter pylori seropositivity's association with markers of iron, 1-carbon metabolism, and antioxidant status among US adults: a structural equations modeling approach.

    Directory of Open Access Journals (Sweden)

    May A Beydoun

    Full Text Available We tested a model in which Helicobacter pylori seropositivity (Hps predicted iron status, which in turn acted as a predictor for markers of 1-C metabolism that were then allowed to predict antioxidant status.National Health and Nutrition Examination Surveys (NHANES 1999-2000 cross-sectional data among adults aged 20-85 y were analyzed (n = 3,055. Markers of Hps, iron status (serum ferritin and transferrin saturation (TS; 1-C metabolism (serum folate (FOLserum, B-12, total homocysteine (tHcy, methylmalonic acid (MMA and antioxidant status (vitamins A and E were entered into a structural equations model (SEM.Predictors of Hps included older age, lower education and income, racial/ethnic groups (lowest among Non-Hispanic Whites, and lifetime cigarette smoking. SEM modeling indicated that Hps had a direct inverse relationship with iron status (combining serum ferritin and TS which in turn was positively related to 1-C metabolites (higher serum folate, B-12 or lower tHcy/MMA that were positively associated with antioxidant status (combining serum vitamins A and E. Another pathway that was found bypassed 1-C metabolites (Hps → Iron_st → Antiox. The sum of all indirect effects from Hps combining both pathways and the other indirect pathways in the model (Hps → Iron_st → OneCarbon; Hps →OneCarbon →Antiox was estimated at β = -0.006±0.003, p<0.05.In sum, of the total effect of H. pylori seropositivity on antioxidant status, two significant indirect pathways through Iron status and 1-Carbon metabolites were found. Randomized controlled trials should be conducted to uncover the concomitant causal effect of H. pylori eradication on improving iron status, folate, B-12 and antioxidant status among H. pylori seropositive individuals.

  20. Effect of antioxidant therapy on hepatic fibrosis and liver iron concentrations in β-thalassemia major patients.

    Science.gov (United States)

    Elalfy, Mohsen S; Adly, Amira A M; Attia, Atef A M; Ibrahim, Fatma A; Mohammed, Amer S; Sayed, Abdelbasset M

    2013-01-01

    To assess the effects of combined vitamin therapy on oxidant-antioxidant hepatic status and hemoglobin (Hb) derivatives on β-thalassemia major (β-TM), a prospective study of 60 β-TM patients aged 4 to 17 years, was conducted. Thirty-nine patients with initial low serum vitamins E, C and A, were treated with oral combined vitamins for 1 year compared to 21 patients with normal vitamin levels. Serum transaminases, serum ferritin, hepatic fibroscan elastography (TE) and magnetic resonance imaging R2* (MRI R2*) for liver iron concentration (LIC), were assessed before and after 6 and 12 months of therapy. Antioxidant capacity was assessed by levels of reduced glutathione (GSH), malondialdehyde (MDA), catalase, superoxide dismutase and GSH enzymes. The studied vitamins, reduced GSH and Hb levels were significantly elevated and paralleled by progressive decline in MDA and ferritin during therapy (p 12 kPa) at baseline compared to 20.5% after therapy (p >0.05), although LIC values were significantly decreased (p <0.001). Combined vitamin therapy improves the antioxidant/oxidant balance, LIC and hepatic fibrosis in young β-TM patients.

  1. Flame atomic absorption spectrometric determination of zinc, nickel, iron and lead in different matrixes after solid phase extraction on sodium dodecyl sulfate (SDS)-coated alumina as their bis (2-hydroxyacetophenone)-1, 3-propanediimine chelates

    International Nuclear Information System (INIS)

    A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in food samples has been reported. The method is based on the adsorption of zinc, nickel, iron and lead on sodium dodecyl sulfate (SDS)-coated alumina, which is also chelated with bis (2-hydroxyacetophenone)-1, 3-propanediimine (BHAPN). The retained analyte ions on modified solid phase were eluted using 8 mL of 4 mol L-1 HNO3. The analyte determinations were carried out by flame atomic absorption spectrometry. The influences of some metal ions and anions on the recoveries of understudy analyte ions were investigated. The proposed method has been successfully applied for the evaluation of these trace and toxic metals in some traditional food samples from Iran.

  2. Antioxidant Properties of the Extracts of Talinum Triangulare and its Effect on Antioxidant enzymes in Tissue Homogenate of Swiss Albino Rat

    OpenAIRE

    Afolabi, Olakunle Bamikole; Oloyede, Omotade Ibidun

    2014-01-01

    Objectives: This study was designed to put into consideration both the in vitro and in vivo investigations on Talinum triangulare (Tt), an herbaceous perennial plant that is a native of tropical America and one of the most important vegetables in Nigeria. Methods: Total phenolic contents in (mg GAE/100 g), flavonoid contents, the ferric reducing antioxidant properties (FRAP), 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl free radical scavenging ability (OH-) and iron chelating ability were ...

  3. Dysregulation of Iron Metabolism in Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Satoru Oshiro

    2011-01-01

    Full Text Available Dysregulation of iron metabolism has been observed in patients with neurodegenerative diseases (NDs. Utilization of several importers and exporters for iron transport in brain cells helps maintain iron homeostasis. Dysregulation of iron homeostasis leads to the production of neurotoxic substances and reactive oxygen species, resulting in iron-induced oxidative stress. In Alzheimer's disease (AD and Parkinson's disease (PD, circumstantial evidence has shown that dysregulation of brain iron homeostasis leads to abnormal iron accumulation. Several genetic studies have revealed mutations in genes associated with increased iron uptake, increased oxidative stress, and an altered inflammatory response in amyotrophic lateral sclerosis (ALS. Here, we review the recent findings on brain iron metabolism in common NDs, such as AD, PD, and ALS. We also summarize the conventional and novel types of iron chelators, which can successfully decrease excess iron accumulation in brain lesions. For example, iron-chelating drugs have neuroprotective effects, preventing neural apoptosis, and activate cellular protective pathways against oxidative stress. Glial cells also protect neurons by secreting antioxidants and antiapoptotic substances. These new findings of experimental and clinical studies may provide a scientific foundation for advances in drug development for NDs.

  4. Antioxidative low molecular weight compounds in marinated herring (Clupea harengus) salt brine

    DEFF Research Database (Denmark)

    Gringer, Nina; Safafar, Hamed; du Mesnildot, Axelle;

    2016-01-01

    This study aimed at unravelling the antioxidative capacity of low molecular weight compounds (LMWC) (peptides, amino acids and phenolic acids) present in salt brines from the marinated herring production. Brines were fractionated into <10 kDa fractions using dialysis and further into 94 fractions...... salt brines contain LMWC holding ABTS-radical scavenging activity, reducing power and iron chelating activity. Generally, a strong correlation between TPC and ABTSradical scavenging was found. In contrast, reducing power and iron chelating activity seemed to be caused by peptides. Protein....../peptide sequencing revealed 1 kDa peptides with the presence of HDFmotif which could be responsible for some of the antioxidant capacity observed in marinated herring salt brine....

  5. Hematological and Immunological Studies on the Effect of Hepatitis B Virus Vaccination in Hepatitis and Non-Hepatitis, Iron Chelating Dependent or Independent Egyptian Thalassemia Patients

    OpenAIRE

    Eman G. Helal*, Ali F.M. El-Sayed**, Noran Abu- Ouf* , Nahla G. Mohamed** and Mona A.M. Ahmed

    2013-01-01

    Background: Regular transfusion in thalassemia major patients increases life expectancy and improves quality of life. Blood transfusion is the main sources for viral transmission to Thalassemia patients. So, detection of viral antigens using more than one technique must be adopted. Iron and its binding proteins have immune regulatory properties and shifting of immune regulatory balance by iron excess or deficiency may produce severe deleterious physiological effects. Thus, the aim of this stu...

  6. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    The interest in the role of ferrous iron in diabetes pathophysiology has been revived by recent evidence of iron as an important determinant of pancreatic islet inflammation and as a biomarker of diabetes risk and mortality. The iron metabolism in the β-cell is complex. Excess free iron is toxic......, but at the same time, iron is required for normal β-cell function and thereby glucose homeostasis. In the pathogenesis of diabetes, iron generates reactive oxygen species (ROS) by participating in the Fenton chemistry, which can induce oxidative damage and apoptosis. The aim of this review is to present...... and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...

  7. Novel Lipid-Soluble Thiol-Redox Antioxidant and Heavy Metal Chelator, N,N′-bis(2-Mercaptoethyl)Isophthalamide (NBMI) and Phospholipase D-Specific Inhibitor, 5-Fluoro-2-Indolyl Des-Chlorohalopemide (FIPI) Attenuate Mercury-Induced Lipid Signaling Leading to Protection Against Cytotoxicity in Aortic Endothelial Cells

    OpenAIRE

    Secor, Jordan D.; Kotha, Sainath R.; Gurney, Travis O.; Patel, Rishi B.; Kefauver, Nicholas R.; Gupta, Niladri; Morris, Andrew J.; Haley, Boyd E.; Parinandi, Narasimham L.

    2011-01-01

    Here, we investigated thiol-redox-mediated phospholipase D (PLD) signaling as a mechanism of mercury cytotoxicity in mouse aortic endothelial cell (MAEC) in vitro model utilizing the novel lipid-soluble thiol-redox antioxidant and heavy metal chelator, N,N′-bis(2-mercaptoethyl)isophthalamide (NBMI) and the novel PLD-specific inhibitor, 5-fluoro-2-indolyl des-chlorohalopemide (FIPI). Our results demonstrated (i) mercury in the form of mercury(II) chloride, methylmercury, and thimerosal induced...

  8. Chemical Characterization, Antioxidant and Enzymatic Activity of Brines from Scandinavian Marinated Herring Products

    DEFF Research Database (Denmark)

    Gringer, Nina; Osman, Ali; Nielsen, Henrik Hauch;

    2014-01-01

    Brines generated during the last marination step in the production of marinated herring (Clupea harengus) were chemically characterized and analyzed for antioxidant and enzyme activities. The end-products were vinegar cured, spice cured and traditional barrel-salted herring with either salt...... or spices. The chemical characterization encompassed pH, dry matter, ash, salt, fatty acids, protein, polypeptide pattern, iron and nitrogen. The antioxidant activity was tested with three assays measuring: iron chelation, reducing power and radical scavenging activity. The enzymatic activity for peroxidase...... and protease were also tested. Results revealed that the brine can contain up to 56.7 mg protein/ mL, up to 20.1 mg fatty acid/mL, good antioxidant activity, high amounts of the antioxidative amino acids lysine, alanine, and glycine, and high enzymatic activity. The potential of using the protein-rich fraction...

  9. Fortification with iron chelate and substitution of sucrose by sucralose in light uvaia sherbet (Eugenia pyriformis Cambess): physical, chemical and sensory characteristics.

    Science.gov (United States)

    Giarola, Tales Márcio de Oliveira; Pereira, Cristina Guimarães; de Resende, Jaime Vilela

    2015-09-01

    In this work, iron fortified light uvaia sherbet, with low sucrose content, was developed and its physical, chemical and sensory characteristics were evaluated. The central composite rotational design (CCRD), applicable to the response surface methodology, was used to analyze the formulations. In the formulations, in addition of iron fortification (9 to 15 mg/100 g), the sucrose was substituted by micronized sucralose in a proportion of 66-94 %. The responses were analyzed with respect to changes in pH, total solids, ash, carbohydrates, proteins, calories, overrun, nucleation and thawing temperatures, rheological parameters and sensory attributes. Protein contents and acidity were similar in all formulations. There was a reduction of over 25 % in the caloric value. The rheological results showed pseudoplastic behavior and significant viscosity differences among the tested sherbets. In the overrun and thawing behavior results the sucrose concentration had a significant influence as the formulations with substitution by 28 g of sucralose/kg of sucrose showed greater air incorporation. In the flavor attribute there was not significance in relation to the iron fortification. Sherbets prepared with substitution of sucrose by sucralose and fortified with iron showed good acceptability, more stability and more resistant to thawing.

  10. The root ferric-chelate reductase of Ceratonia siliqua (L.) and Poncirus trifoliata (L.) Raf. responds differently to a low level of iron

    OpenAIRE

    Pestana, M; Gama, Florinda; Saavedra, Teresa; de Varennes, Amarilis; P.J. Correia

    2012-01-01

    Iron (Fe) deficiency is a common nutritional disorder in several crops grown in calcareous soils, but some species are well adapted to these conditions. A hydroponic experiment was conducted to compare the response of a calcicole species Ceratonia siliqua L. (carob) and of Poncirus trifoliata (L.) Raf., a citrus rootstock very sensitive to Fe deficiency. Rootstocks from both species were grown in nutrient solutions without Fe (0 M Fe), with 1 M Fe, and with 10 M Fe (carob) or 4...

  11. The preparation and antioxidant activity of glucosamine sulfate

    Institute of Scientific and Technical Information of China (English)

    XING Ronge; LIU Song; WANG Lin; CAI Shengbao; YU Huahua; FENG Jinhua; LI Pengcheng

    2009-01-01

    Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O(2))/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O(2) scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL.However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.

  12. Applied research on domestic MCS chelated iron desulfurization process in Western Sichuan marine sour gas reservoir%国产MCS络合铁脱硫工艺在川西海相含硫气田的应用研究

    Institute of Scientific and Technical Information of China (English)

    姚广聚; 陈海龙; 赵凯; 彭红利

    2015-01-01

    川西海相气藏目前处于勘探开发评价阶段,所开采的天然气中 H2 S摩尔分数为0.7%~5%,需进行单井脱硫试采并开展气藏评价。针对该气藏第一口试采井CK1井MCS国产络合铁脱硫工艺进行了跟踪分析,对现场的环保及硫堵问题进行了脱硫工艺的调整和优化,提出工艺推广建议,计算了装置的运行能耗及运行成本。目前,该井M C S络合铁脱硫装置年操作时间超过8000 h ,日生产硫膏4 t ,累计生产天然气8500×104 m3,与工艺优化前相比,天然气年产量提高约625×104 m3,保证了该井的顺利试采和川西海相气藏的有效评价,可为同类含硫气井试采提供参考。%Western Sichuan marine gas reservoir is in the exploration and development evaluation stage at present .The natural gas contains 0 .7% -5% hydrogen sulfide ,which needs the single well desulfurization test mining and gas reservoir evaluation .The tracking analysis of the first oral produc‐tion well (Chuanke 1) using MCS domestic chelated iron desulfurization process was carried out .Ai‐ming at the environmental protection and sulfur plugging problems ,the desulfurization process was adjusted and optimized ,the suggestions for process popularizing were put forward ,and the operating energy consumption and costs were calculated .Currently the operating time of MCS chelated iron des‐ulfurization unit is over 8 000 h per year ,sulfur ointment production is 4 t/d ,and the cumulative pro‐duction of natural gas is 85 × 106 m3 ,which increase about 6 .25 × 106 m3 per year compared with the annual output of natural gas before optimization .It ensures the successfully test mining of the well and the effective evaluation of Western Sichuan marine gas reservoir ,w hich can provide references for the production test of similar sour gas well .

  13. Macrocyclic bifunctional chelating agents

    Science.gov (United States)

    Meares, Claude F.; DeNardo, Sally J.; Cole, William C.; Mol, Min K.

    1987-01-01

    A copper chelate conjugate which is stable in human serum. The conjugate includes the copper chelate of a cyclic tetraaza di-, tri-, or tetra-acetic acid, a linker attached at one linker end to a ring carbon of the chelate, and a biomolecule joined at the other end of the linker. The conjugate, or the linker-copper chelate compound used in forming the conjugate, are designed for use in diagnostic and therapeutic applications which involve Cu(II) localization via the systemic route.

  14. Effect of iron stress on Withania somnifera L.: antioxidant enzyme response and nutrient elemental uptake of in vitro grown plants.

    Science.gov (United States)

    Rout, Jyoti Ranjan; Behera, Sadhana; Keshari, Nitin; Ram, Shidharth Sankar; Bhar, Subhajit; Chakraborty, Anindita; Sudarshan, Mathummal; Sahoo, Santi Lata

    2015-03-01

    In the present study the response of antioxidant enzyme activities and the level of expression of their corresponding genes on bioaccumulation of iron (Fe) were investigated. In vitro germinated Withania somnifera L. were grown in Murashige and Skoog's liquid medium with increasing concentrations (0, 25, 50, 100 and 200 µM) of FeSO4 for 7 and 14 days. Root and leaf tissues analyzed for catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1) and guaiacol peroxidase (GPX, EC 1.11.1.7), have shown an increase in content with respect to exposure time. Isoforms of CAT, SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and observed that the isoenzymes were greatly affected by higher concentrations of Fe. Reverse transcriptase polymerase chain reaction analysis performed by taking three pairs of genes of CAT (RsCat, Catalase1, Cat1) and SOD (SodCp, TaSOD1.2, MnSOD) to find out the differential expression of antioxidant genes under Fe excess. RsCat from CAT and MnSOD from SOD have exhibited high levels of gene expression under Fe stress, which was consistent with the changes of the activity assayed in solution after 7 days of treatment. Analysis by proton induced X-ray emission exhibited an increasing uptake of Fe in plants by suppressing and expressing of other nutrient elements. The results of the present study suggest that higher concentration of Fe causes disturbance in nutrient balance and induces oxidative stress in plant.

  15. Antioxidant Enzymes and Physiological Responses of Safflower (Carthamus tinctorius L.) to Iron Application, under Water Deficit Condition

    OpenAIRE

    Kayvan Fathi AMIRKHIZ; Majid Amini DEHAGHI; Siavash HESHMATI

    2015-01-01

    The effect of soil and foliar iron (Fe) application on the activity of some antioxidant enzymes and plant metabolites of Carthamus tinctorius L. (IL111), under water stress conditions was tested. The results showed that under drought stress conditions, the activity of ascorbate peroxidase, superoxide dismutase, polyphenol oxidase and catalase enzymes increased with soil application of Fe. In contrast, the activity of peroxidase enzyme under drought conditions increased with foliar application...

  16. 51例重型β珠蛋白生成障碍性贫血患儿长期输血去铁治疗与铁过载的关系研究%Relationship of long-term blood transfusion, iron chelation therapy with iron overload in 51 children with beta-thalassaemia major

    Institute of Scientific and Technical Information of China (English)

    陈光福; 陈娟娟; 高红英; 龙琦; 富国华

    2012-01-01

    Objective To explore the relationship of long-term blood transfusion, iron chelation therapy with iron overload in the patients with beta-thalassaemia major. Methods The serum ferritin (SF) , liver function, renal function, myocardial enzyme, ultrasonograph of liver and spleen, blood glucose and urine glucose were detected in the patients with beta-thalassaemia major in "Friends of thalassemia" and "Service team for thalassemia in Shenzhen" with regular long-term blood transfusion and iron chelation therapy in three months. Left ventricular ejection fraction (LVEF) , myocardial, liver, pancreas and pituitary MR imaging T2* were performed on 51 patients of them. The51 patients were divided into 3 groups. 10 cases with sufficient dose DFO and sufficient dose DFP iron chelation treatment group (sufficient dose joint group) ; 31 cases with insufficient DFO and DFP iron chelation treatment group (insufficient joint group) ; 10 cases with sufficient dose DFX iron chelation treatment group (DFX group). Results There was no difference in myocardial T2*, pituitary T2*, LVEF in every group. (P > 0.05). Liver T2* in sufficient dose joint group was higher than that in insufficient joint group (P 0.05), and there was moderate negative correlation with liver T2*(r = 0.558,P < 0.01). Conclusion The sufficient dose DFO with DFP treatment, and the DFX treatment can effectively reduce SF, compared with that of insufficient DFO with DFP treatment. All iron chelation therapy can alleviate myocardial iron overload.%目的 探讨重型β珠蛋白生成障碍性贫血(beta-thalassaemia,简称β -TM)患儿长期输血、去铁治疗与铁过载的关系.方法 深圳市第二人民医院2001年成立“地贫之友”与“地贫服务队”,对β-TM患儿进行规范性的长期输血和去铁治疗.每3个月监测血清铁蛋白浓度(SF)、肝肾功能、心肌酶谱、心功能、心脏和肝脾B超、血糖和尿糖.2001年2月至2010年6月对其中51例患儿进

  17. The Chelate Effect Redefined.

    Science.gov (United States)

    da Silva, J. J. R. Frausto

    1983-01-01

    Discusses ambiguities of the accepted definition of the chelate effect, suggesting that it be defined in terms of experimental observation rather than mathematical abstraction. Indicates that the effect depends on free energy change in reaction, ligand basicity, pH of medium, type of chelates formed, and concentration of ligands in solution. (JN)

  18. ANTIOXIDANT MUSHROOMS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Aggarwal Preeti

    2012-06-01

    Full Text Available The antioxidant properties of wild mushrooms have been extensively studied and many antioxidant compounds such as phenolic compounds, tocopherols, ascorbic acid, and carotenoids identified. The various antioxidant mechanisms of the mushroom species extracts may be attributed to strong hydrogen-donating ability, metal-chelating ability, and their effectiveness as good scavengers of superoxide and free radicals. This indicates the potential of mushrooms as panacea for many diseases and also reveals a novel potential to fight against tumors in man.

  19. 复合氨基酸络合铁、锌对肥育猪铁、锌吸收代谢的影响%Effects of Iron and Zinc Complex Amino Acid Chelate on Absorption Metabolism of Iron and Zinc of Finishing Pigs

    Institute of Scientific and Technical Information of China (English)

    詹康; 占今舜; 赵国琦; 霍永久

    2014-01-01

    本试验旨在研究复合氨基酸络合铁、锌对肥育猪血液生化指标,血清中免疫球蛋白含量,毛发中铁、锌含量及铁、锌表观消化率的影响。选择体重[(55.63±1.33)kg]相近的“杜×长×大”肥育猪36头,随机分至对照组和2个试验组,每组3个重复,每个重复4头猪。对照组饲喂铁、锌含量均为100 mg/kg(由硫酸亚铁、硫酸锌提供)的基础饲粮,试验1组饲喂铁、锌含量均为50 mg/kg(由硫酸亚铁、硫酸锌提供)+50 mg/kg(由复合氨基酸络合铁、锌提供)的基础饲粮,试验2组饲喂铁、锌含量均为100 mg/kg(由复合氨基酸络合铁、锌提供)的基础饲粮。结果表明:1)3组间的红细胞数量、血细胞压积、血清免疫球蛋白A和免疫球蛋白M含量无显著差异( P>0.05)。2)试验2组的血红蛋白含量和血清免疫球蛋白 G含量显著高于对照组( P<0.05)。3)试验2组毛发中铁含量显著高于对照组( P<0.05),试验2组毛发中锌含量显著高于试验1组和对照组( P<0.05);4)试验2组粪中铁含量和试验2组、试验1组粪中锌含量显著低于对照组( P<0.05);3组间铁和锌表观消化率无显著差异( P>0.05)。由此可见,添加复合氨基酸络合铁、锌可显著增加肥育猪血红蛋白、血清免疫球蛋白G含量及毛发中铁、锌含量,显著降低粪中铁、锌含量。%To study the effects of iron and zinc complex amino acid chelate on blood biochemical indexes,im-munoglobulin content in serum,iron and zinc contents in hair and apparent digestibility of iron and zinc of fin-ishing pigs,thirty-six finishing pigs( Duroc × Landrace × Yorkshire ) with an average initial body weight of (55.63±1.33)kg were selected and randomly allotted to three groups. There were three replicates per group and four pigs in each replicate. Pigs of the control group fed a basal diet with 100 mg

  20. Dysregulation of iron of amyotrophic lateral sclerosis mice and neuroprotective effects of iron chelator%肌萎缩侧索硬化小鼠脊髓铁离子浓度及铁离子螯合剂的神经保护作用

    Institute of Scientific and Technical Information of China (English)

    王倩; 张晓洁; 乐卫东

    2009-01-01

    AIM To observe the change of iron accumulation in spinal cords of amyotrophic lateral sclerosis(ALS)mice and the neuroprotective effects,and mechanism of iron chelators in the mice model. METHODS After iron chelators VK-28 or M3O administration,the onset of morbidity and life span of the transgenic mice was observed,the levels of iron and MDA and the activity of SOD in spinal cords of SOD1- G93A mice and wide type(WT)mice were assessed by using proper kits,and spinal motor neuron and active glias were counted by spectrophotometry. RESULTS The iron levels in spinal cords of SOD1-G93A transgenic mice were significantly increased compared with WT mice at age of 90 d (42%, P < 0.05) and 120 d (82%, P < 0.01). And it was attenuated by iron chelators VK-28 and M30 at the age of 90 d (μg·g~(-1)protein, 1784 ± s 132, 2 103 ± 983 vs. 2 398 ± 243; both P < 0.05) and 120 d (μg·g~(-1) protein, 2 080 ±118, 2 483 ± 134 vs. 3 180 ± 201; both P < 0.01). Compared with the SOD1-G93A control group, VK-28 and M30 significantly delayed the onset of morbidity ((116.2 ± 4.4) d, (110.5 ± 3.7) d vs. (104.5 ± 1.7); both P < 0.05) and extended the survival ((139.3 ± 3.9) d, (134.6 ±2.1) d vs. (126.5 ± 2.2) d; P < 0.01, P < 0.05) , accompanied by a significant reduction of motor neuron loss (P < 0.01). Moreover, the chelators reversed the increased MDA level and the decreased SOD activity (P < 0.05, P < 0.01), and suppressed the activation of microglia (P < 0.01) and astrocytes (P < 0.01). CONCLUSION There were increased iron accumulation in spinal cord of SOD1-G93A transgenic mice. Iron chelators VK-28 and M30 therapy may have neuroprotective potential for ALS by decreasing the levels of iron and oxygen free radicals in the spinal cords.%目的 探讨肌萎缩侧索硬化(ALS)小鼠脊髓中铁离子的异常变化和铁离子螯合剂的神经保护作用及其可能机制.方法 SOD1-G93A转基因小鼠腹腔注射铁离子螯合剂VK-28(5 mg·kg~(-1))及M3O(5 mg

  1. Lead toxicosis of captive vultures: case description and responses to chelation therapy

    Directory of Open Access Journals (Sweden)

    Pikula Jiri

    2013-01-01

    Full Text Available Abstract Background Lead, a serious threat for raptors, can hamper the success of their conservation. This study reports on experience with accidental lead intoxication and responses to chelation therapy in captive Cinereous (Aegypius monachus and Egyptian (Neophron percnopterus Vultures. Results Soil contamination by lead-based paint sanded off the steel aviary resulted in poisoning of eight Cinereous and two Egyptian Vultures. A male Egyptian Vulture developed signs of apathy, polydipsia, polyuria, regurgitation, and stupor, and died on the next day. Liver, kidney and blood lead concentrations were 12.2, 8.16 and 2.66 μg/g, respectively. Laboratory analyses confirmed severe liver and kidney damage and anaemia. Blood Pb levels of Pb-exposed Cinereous Vultures were 1.571 ± 0.510 μg/g shortly after intoxication, decreased to 0.530 ± 0.165 μg/g without any therapy in a month and to 0.254 ± 0.097 μg/g one month after CaNa2EDTA administration. Eight months later, blood lead levels decreased to close to the background of the control group. Blood parameters of healthy Pb-non-exposed Cinereous Vultures were compared with those of the exposed group prior to and after chelation therapy. Iron levels in the lead-exposed pre-treatment birds significantly decreased after chelation. Haematocrit levels in Pb-exposed birds were significantly lower than those of the controls and improved one month after chelation. Creatine kinase was higher in pre-treatment birds than in the controls but normalised after therapy. Alkaline phosphatase increased after chelation. A marked increase in the level of lipid peroxidation measured as thiobarbituric acid reactive species was demonstrated in birds both prior to and after chelation. The ferric reducing antioxidant power was significantly lower in pre-treatment vultures and returned to normal following chelation therapy. Blood metallothionein levels in lead-exposed birds were higher than in controls

  2. Metal based pharmacologically active agents: Synthesis, structural characterization, molecular modeling, CT-DNA binding studies and in vitro antimicrobial screening of iron(II) bromosalicylidene amino acid chelates

    Science.gov (United States)

    Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.; Ismael, Mohamed; Seleem, Amin Abdou

    2014-01-01

    In recent years, great interest has been focused on Fe(II) Schiff base amino acid complexes as cytotoxic and antitumor drugs. Thus a series of new iron(II) complexes based on Schiff bases amino acids ligands have been designed and synthesized from condensation of 5-bromosalicylaldehyde (bs) and α-amino acids (L-alanine (ala), L-phenylalanine (phala), L-aspartic acid (aspa), L-histidine (his) and L-arginine (arg)). The structure of the investigated iron(II) complexes was elucidated using elemental analyses, infrared, ultraviolet-visible, thermogravimetric analysis, as well as conductivity and magnetic susceptibility measurements. Moreover, the stoichiometry and the stability constants of the prepared complexes have been determined spectrophotometrically. The results suggest that 5-bromosalicylaldehyde amino acid Schiff bases (bs:aa) behave as dibasic tridentate ONO ligands and coordinate to Fe(II) in octahedral geometry according to the general formula [Fe(bs:aa)2]ṡnH2O. The conductivity values between 37 and 64 ohm-1 mol-1 cm2 in ethanol imply the presence of nonelectrolyte species. The structure of the complexes was validated using quantum mechanics calculations based on accurate DFT methods. Geometry optimization of the Fe-Schiff base amino acid complexes showed that all complexes had octahedral coordination. In addition, the interaction of these complexes with (CT-DNA) was investigated at pH = 7.2, by using UV-vis absorption, viscosity and agarose gel electrophoresis measurements. Results indicated that the investigated complexes strongly bind to calf thymus DNA via intercalative mode and showed a different DNA binding according to the sequence: bsari > bshi > bsali > bsasi > bsphali. Moreover, the prepared compounds are screened for their in vitro antibacterial and antifungal activity against three types of bacteria, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus and three types of anti fungal cultures, Penicillium purpurogenium, Aspergillus

  3. Cholinesterases inhibitory and antioxidant activities of Harpagophytum procumbens from in vitro systems.

    Science.gov (United States)

    Georgiev, Milen I; Alipieva, Kalina; Orhan, Ilkay Erdogan

    2012-02-01

    A previous report showed that extracts of cell suspension and transformed root cultures of Harpagophytum procumbens (commonly known as Devil's claw), an African plant with high medicinal value, exhibit strong antiinflammatory characteristics. The present work tests the ability of extracts, phenylethanoid-containing fractions and the major phenylethanoid glycoside isolated from the Devil's claw cultures, to inhibit acetylcholinesterase and butyrylcholinesterase, and the antioxidant activity in iron-related systems (e.g. ferric-reducing antioxidant power and ferrous ion-chelating capacity). The results indicated that the phenylethanoid fractions may be attractive for various commercial purposes since they displayed significant cholinesterase inhibitory activity (even higher than that of pure galanthamine in the case of butyrylcholinesterase inhibition assay). Crude methanolic extracts from cell and hairy root cultures of Devil's claw exhibited strong ferrous ion-chelating capacity (1.5-2 times higher than pure butylated hydroxyanisole, used as positive standard). PMID:21721061

  4. Iron

    Science.gov (United States)

    ... as recommended by an obstetrician or other health care provider. Infants and toddlers Iron deficiency anemia in infancy can lead to delayed psychological development, social withdrawal, and less ability to pay attention. By age 6 to 9 months, full-term infants could ...

  5. Antioxidant potential of water hyacinth (Eichornia crassipes): In vitro antioxidant activity and phenolic composition

    DEFF Research Database (Denmark)

    Surendraraj, A.; Farvin, Sabeena; Anandan, R.

    2013-01-01

    and in the antioxidant activities of extracts from the various parts of E. crassipes. Out of the 11 phenolic acids analyzed, ethanolic extracts contained high amounts of gallic, protocatechuic, gentisic, and p-hydroxybenzoic acid, whereas, water extracts contained less amounts of a varied number of phenolic acids......The aims of the present study were (a) to extract and quantify the main phenolic acids and tocopherols from the petiole, leaves, and flowers of Eichornia crassipes; (b) to evaluate the antioxidant capacity of the extracts in four in vitro systems (1,1-diphenyl-2-pycryl-hydrazyl [DPPH] radical...... scavenging ability, iron chelating activity, reducing power, and prevention of oxidation in a liposome model system); and (c) its effectiveness in retarding lipid peroxidation in fish oil by accelerated stability test. Significant differences were observed in total and individual phenolic contents...

  6. Ferrocene base metal chelates

    International Nuclear Information System (INIS)

    Review of the works, devoted to different types of ferrocene metal chelates and to a possibility of ferrocene-containing ligand modification by means of complexing, is presented. Structure, properties and spectral characteristics of transitional metal, rare earth element, Cd2+, UO22+, Th4+ etc. complexes with ferrocene diketones, ferrocene acyl derivatives based on thiosemicarbazones and hydrazones and other heterometal ferrocene-containing metal chelates, are considered. 134 refs., 1 tab

  7. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  8. Carot-4-en-9,10-diol, a conidiation-inducing sesquiterpene diol produced by Trichoderma virens PS1-7 upon exposure to chemical stress from highly active iron chelators.

    Science.gov (United States)

    Wang, Mengcen; Hashimoto, Makoto; Hashidoko, Yasuyuki

    2013-03-01

    To screen biocontrol agents against Burkholderia plantarii, the causative agent of rice seedling blight, we employed catechol, an analog of the virulence factor tropolone, to obtain chemical stress-resistant microorganisms. The fungal isolate PS1-7, identified as a strain of Trichoderma virens, showed the highest resistance to catechol (20 mM) and exhibited efficacy as a biocontrol agent for rice seedling blight. During investigation of metabolic traits of T. virens PS1-7 exposed to catechol, we found a secondary metabolite that was released extracellularly and uniquely accumulated in the culture. The compound induced by chemical stress due to catechol was subsequently isolated and identified as a sesquiterpene diol, carot-4-en-9,10-diol, based on spectroscopic analyses. T. virens PS1-7 produced carot-4-en-9,10-diol as a metabolic response to tropolone at concentrations from 0.05 to 0.2 mM, and the response was enhanced in a dose-dependent manner, similar to its response to catechol at concentrations from 0.1 to 1 mM. Some iron chelators, such as pyrogallol, gallic acid, salicylic acid, and citric acid, at 0.5 mM also showed activation of T. virens PS1-7 production of carot-4-en-9,10-diol. This sesquiterpene diol, formed in response to chemical stress, promoted conidiation of T. virens PS1-7, suggesting that it is involved in an autoregulatory signaling system. In a bioassay of the metabolic and morphological responses of T. virens PS1-7, conidiation in hyphae grown on potato dextrose agar (PDA) plates was either promoted or induced by carot-4-en-9,10-diol. Carot-4-en-9,10-diol can thus be regarded as an autoregulatory signal in T. virens, and our findings demonstrate that intrinsic intracellular signaling regulates conidiation of T. virens. PMID:23315728

  9. Nanoparticle and other metal chelation therapeutics in Alzheimer disease.

    Science.gov (United States)

    Liu, Gang; Garrett, Matthew R; Men, Ping; Zhu, Xiongwei; Perry, George; Smith, Mark A

    2005-09-25

    Current therapies for Alzheimer disease (AD) such as the anticholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of disease, but do not arrest disease progression or supply meaningful remission. As such, new approaches to disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. In this review, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show a unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may prove to be a safe and effective means of reducing the metal load in neural tissue thus staving off the harmful effects of oxidative damage and its sequelae.

  10. Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management

    Science.gov (United States)

    Udeigwe, Theophilus K.; Eichmann, Madeleine; Menkiti, Matthew C.

    2016-07-01

    This study was designed to examine the fixation pattern and kinetics of zinc (Zn) in chelated (ethylenediaminetetraacetic acid, EDTA) and non-chelated mixed micronutrient systems of semi-arid alkaline soils from the Southern High Plains, USA. Soils were characterized for a suite of chemical and physical properties and data obtained from extraction experiments fitted to various kinetic models. About 30 % more plant-available Zn was fixed in the non-chelated system within the first 14 days with only about 18 % difference observed between the two systems by day 90, suggesting that the effectiveness of the chelated compounds tended to decrease over time. The strengths of the relationships of change in available Zn with respect to other micronutrients (copper, iron, and manganese) were higher and more significant in the non-chelated system (average R2 of 0.83), compared to the chelated (average R2 of 0.42). Fixation of plant-available Zn was best described by the power-function model (R2 = 0.94, SE = 0.076) in the non-chelated system, and was poorly described by all the models examined in the chelated system. Reaction rate constants and relationships generated from this study can serve as important tools for micronutrient management and for future micronutrient modeling studies on these soils and other semi-arid regions of the world.

  11. Chelation Therapy for Mercury Poisoning

    Directory of Open Access Journals (Sweden)

    Rong Guan

    2009-01-01

    Full Text Available Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role of chelating agents against mercury poisoning, which provides a promising research direction for broader application of chelation therapy in prevention and treatment of mercury poisoning.

  12. Treatment of β-Thalassemia/Hemoglobin E with Antioxidant Cocktails Results in Decreased Oxidative Stress, Increased Hemoglobin Concentration, and Improvement of the Hypercoagulable State

    Directory of Open Access Journals (Sweden)

    Orn-uma Yanpanitch

    2015-01-01

    Full Text Available Studies on the antioxidant treatment for thalassemia have reported variable outcomes. However, treatment of thalassemia with a combination of hydrophobic and hydrophilic antioxidants and an iron chelator has not been studied. This study investigated the effects of antioxidant cocktails for the treatment of β-thalassemia/hemoglobin E (HbE, which is the most common form of β-thalassemia in Southeast Asia. Sixty patients were divided into two groups receiving N-acetylcysteine, deferiprone, and either curcuminoids (CUR or vitamin E (Vit-E, and their hematological parameters, iron load, oxidative stress, and blood coagulation potential were evaluated. Patients were classified as responders if they showed the improvements of the markers of iron load and oxidative stress, otherwise as nonresponders. During treatment, the responders in both groups had significantly decreased iron load, oxidative stress, and coagulation potential and significantly increased antioxidant capacity and hemoglobin concentration. The significantly maximum increase (P<0.01 in hemoglobin concentration was 11% at month 4 in CUR group responders and 10% at month 10 in Vit-E group responders. In conclusion, the two antioxidant cocktails can improve anemia, iron overload, oxidative stress, and hypercoagulable state in β-thalassemia/HbE.

  13. HERBAL ANTIOXIDANTS- A REVIEW

    OpenAIRE

    Swathi K; Priyenka Devi K S*; Sangeetha A

    2016-01-01

    Reactive oxygen species, circulating in the human body tend to react with the electron of other molecules which may initiate the chain reaction and contribute to adverse health effects in the body. Antioxidants possess anti-inflammatory property, antitumor property, anticarcinogenic property, antimutagenic property and metal chelating potential which inturn terminates the chain reaction by arresting free radical intermediates. Natural antioxidants derived from plant sources are effective and ...

  14. Chelation Therapy for Mercury Poisoning

    OpenAIRE

    Rong Guan; Han Dai

    2009-01-01

    Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

  15. Chelation in metal intoxication--Principles and paradigms.

    Science.gov (United States)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, Yang; Andersen, Ole

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new oral iron antidotes deferiprone and desferasirox have entered into the clinical arena. Comparisons of these agents and deferoxamine infusions are in progress. General principles for research and development of new chelators are briefly outlined in this review. PMID:25457281

  16. Rapid reductive degradation of aqueous p-nitrophenol using nanoscale zero-valent iron particles immobilized on mesoporous silica with enhanced antioxidation effect

    International Nuclear Information System (INIS)

    Highlights: • Nanoscale zero-valent iron (nZVI) was doped in mesoporous silica (SBA-15). • High capacity and fast rate for the removal of p-nitrophenol. • Better antioxidant ability of nZVI/SBA-15 than nZVI. • p-Nitrophenol removal depended heavily on immobilized nZVI amount. • Mechanism of PNP removal by nZVI/SBA-15 was proposed. - Abstract: In this study, nanoscale zero-valent iron particles immobilized on mesoporous silica (nZVI/SBA-15) were successfully prepared for effective degradation of p-nitrophenol (PNP). The nZVI/SBA-15 composites were characterized by N2 adsorption/desorption, transmission electron microscopy (TEM), UV–vis spectrum and X-ray photoelectron spectroscopy (XPS). Results showed that abundant ultrasmall nanoscale zero-valent iron particles were formed and well dispersed on mesoporous silica (SBA-15). Batch experiments revealed that PNP removal declined from 96.70% to 16.14% as solution pH increased from 3.0 to 9.0. Besides, degradation equilibrium was reached within 5 min, which was independent of initial PNP concentration. Furthermore, only a little PNP elimination on SBA-15 indicated that nZVI immobilized on mesoporous silica was mainly responsible for the target contaminant removal. The UV–vis spectrum and XPS measurement confirmed that the PNP removal was a reductive degradation process, which was further proved by the detected intermediates using gas chromatography–mass spectrometry (GC/MS). The excellent antioxidation ability had been discovered with more than 80% of PNP being removed by nZVI/SBA-15 treated with 30 days’ exposure to air. These results demonstrated the feasible and potential application of nZVI/SBA-15 composites in organic wastewater treatment

  17. Rapid reductive degradation of aqueous p-nitrophenol using nanoscale zero-valent iron particles immobilized on mesoporous silica with enhanced antioxidation effect

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lin, E-mail: tanglin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Tang, Jing [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Yang, Guide; Xie, Xia; Zhou, Yaoyu [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Pang, Ya [Department of Biological Engineering and Environmental Science, Changsha College, Changsha 410003 (China); Fang, Yan; Wang, Jiajia [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Xiong, Weiping [College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082 (China)

    2015-04-01

    Highlights: • Nanoscale zero-valent iron (nZVI) was doped in mesoporous silica (SBA-15). • High capacity and fast rate for the removal of p-nitrophenol. • Better antioxidant ability of nZVI/SBA-15 than nZVI. • p-Nitrophenol removal depended heavily on immobilized nZVI amount. • Mechanism of PNP removal by nZVI/SBA-15 was proposed. - Abstract: In this study, nanoscale zero-valent iron particles immobilized on mesoporous silica (nZVI/SBA-15) were successfully prepared for effective degradation of p-nitrophenol (PNP). The nZVI/SBA-15 composites were characterized by N{sub 2} adsorption/desorption, transmission electron microscopy (TEM), UV–vis spectrum and X-ray photoelectron spectroscopy (XPS). Results showed that abundant ultrasmall nanoscale zero-valent iron particles were formed and well dispersed on mesoporous silica (SBA-15). Batch experiments revealed that PNP removal declined from 96.70% to 16.14% as solution pH increased from 3.0 to 9.0. Besides, degradation equilibrium was reached within 5 min, which was independent of initial PNP concentration. Furthermore, only a little PNP elimination on SBA-15 indicated that nZVI immobilized on mesoporous silica was mainly responsible for the target contaminant removal. The UV–vis spectrum and XPS measurement confirmed that the PNP removal was a reductive degradation process, which was further proved by the detected intermediates using gas chromatography–mass spectrometry (GC/MS). The excellent antioxidation ability had been discovered with more than 80% of PNP being removed by nZVI/SBA-15 treated with 30 days’ exposure to air. These results demonstrated the feasible and potential application of nZVI/SBA-15 composites in organic wastewater treatment.

  18. MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

    Energy Technology Data Exchange (ETDEWEB)

    Abergel, Rebecca J.; Raymond, Kenneth N.

    2011-07-13

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  19. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, Shih-Ger T.

    1994-01-01

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO.sub.x and optionally SO.sub.2 from a fluid using a metal ion (Fe.sup.2+) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC' is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution.

  20. Iron load

    Directory of Open Access Journals (Sweden)

    Filippo Cassarà

    2013-03-01

    Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.

  1. Efficient solvent extraction of antioxidant-rich extract from a tropical diatom,Chaetoceros calcitrans (Paulsen) Takano 1968简

    Institute of Scientific and Technical Information of China (English)

    Su; Chern; Foo; Fatimah; Md.Yusoff; Maznah; Ismail; Mahiran; Basri; Nicholas; Mun; Hoe; Khong; Kim; Wei; Chan; Sook; Kun; Yau

    2015-01-01

    Objective: To compare the in vitro antioxidant capacity of a diatom, Chaetoceros calcitrans(C. calcitrans) extracted using six types of solvents.Methods: Each extract was evaluated in terms of extraction yield, total carotenoid,fucoxanthin content, total phenolic and antioxidant capacities(DPPH and ABTS +scavenging activity and iron chelating activity).Results: The methanol extract exhibited the highest yield [(22.71 ± 0.96) g/100 g dry weight(DW)], total carotenoid [(4.46 ± 0.36) mg/g DW], total phenolic [(2.49 ± 0.08) mg gallic acid equivalents/g DW] and second highest fucoxanthin content [(2.08 ± 0.03) mg fucoxanthin/g DW] as compared to other solvent extracts. Methanolic extract also exhibited significantly higher(P < 0.05) scavenging(DPPH, ABTS +) and iron chelating activities.Conclusions: Methanol was the recommended solvent for the production of antioxidant rich extract from C. calcitrans. Both carotenoids and phenolic acids were found to be positively correlated to the antioxidant capacities of C. calcitrans. Lead bioactives confirmed by subsequent high performance liquid chromatography studies were fucoxanthin, gallic acid and protocatechuic acid.

  2. Heavy metal chelation in neurotoxic exposures.

    Science.gov (United States)

    Jang, David H; Hoffman, Robert S

    2011-08-01

    Metals such as iron and copper are critical to living organisms, whereas other metals such as lead and arsenic have no known biologic role. Any metals in large amounts may cause toxicity. Many metals cause pervasive systemic effects involving the nervous system, which can be subtle in some cases. Although challenging, the diagnosis and treatment of metal poisoning can be made based on history, physical examination, and the proper use of metal testing. This article focuses on the use, and misuse, of chelation in the diagnosis and management of metal intoxication. PMID:21803213

  3. Phenolic Compounds of Cereals and Their Antioxidant Capacity.

    Science.gov (United States)

    Van Hung, Pham

    2016-01-01

    Phenolic compounds play an important role in health benefits because of their highly antioxidant capacity. In this review, total phenolic contents (TPCs), phenolic acid profile and antioxidant capacity of the extracted from wheat, corn, rice, barley, sorghum, rye, oat, and millet, which have been recently reported, are summarized. The review shows clearly that cereals contain a number of phytochemicals including phenolics, flavonoids, anthocyanins, etc. The phytochemicals of cereals significantly exhibit antioxidant activity as measured by trolox equivalent antioxidant capacity (TEAC), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity (ORAC), inhibition of oxidation of human low-density lipoprotein (LDL) cholesterol and DNA, Rancimat, inhibition of photochemilumenescence (PCL), and iron(II) chelation activity. Thus, the consumption of whole grains is considered to have significantly health benefits in prevention from chronic diseases such as cardiovascular disease, diabetes, and cancer because of the contribution of phenolic compounds existed. In addition, the extracts from cereal brans are considered to be used as a source of natural antioxidants. PMID:25075608

  4. A Copper Chelate of Thiosemicarbazone NSC 689534 induces Oxidative/ER Stress and Inhibits Tumor Growth In Vitro and In Vivo

    Science.gov (United States)

    Hancock, Chad N.; Stockwin, Luke H.; Han, Bingnan; Divelbiss, Raymond D.; Jun, Jung Ho; Malhotra, Sanjay V.; Hollingshead, Melinda G.; Newton, Dianne L.

    2010-01-01

    In this study, a Cu2+ chelate of the novel thiosemicarbazone NSC 689534 was evaluated for in vitro and in vivo anti-cancer activity. Results demonstrated that NSC 689534 activity (low µM range) was enhanced 4–5 fold by copper chelation and completely attenuated by iron. Importantly, once formed, the NSC 689534/Cu2+ complex retained activity in the presence of additional iron or iron-containing biomolecules. NSC 689534/Cu2+ mediated its effects primarily through the induction of ROS, with depletion of cellular glutathione and protein thiols. Pre-treatment of cells with the antioxidant L-NAC impaired activity, whereas NSC 689534/Cu2+ effectively synergized with the glutathione biosynthesis inhibitor, buthionine sulphoximine. Microarray analysis of NSC 689534/Cu2+-treated cells highlighted activation of pathways involved in oxidative and ER-stress/UPR, autophagy and metal metabolism. Further scrutiny of the role of ER-stress and autophagy indicated that NSC 689534/Cu2+ -induced cell death was ER-stress dependent and autophagy-independent. Lastly, NSC 689534/Cu2+ was shown to have activity in an HL60 xenograft model. These data suggest that NSC 689534/Cu2+ is a potent oxidative stress inducer worthy of further preclinical investigation. PMID:20971185

  5. Reactive polymers: part I - Novel polystyrene-anchored copper (II), nickel (II), cobalt (II), iron (III), zinc (II), cadmium (II), molybdenum (VI) and uranium (VI) complexes of the chelating resin containing thiosemicarbazone

    International Nuclear Information System (INIS)

    A new chelating resin containing thiosemicarbazone has been synthesized by the reaction of aldehydopolystyrene and thiosemicarbazide. The polystyrene bound thiosemicarbazone reacts with salicylaldehyde leading to the formation of a new Schiff base chelating resin which reacts with sodium monochloroacetate and gives the polymer bound S-acetatothiosemicarbazone. The new chelating resin forms complexes of the types PS-LCuX·S, PS-LNiX·3S, PS-LHNi(acac)2, PS-LCoX·3S, PS-LFeX2·2S, PS-LZnX·S, PS-LCdX·S, PS-LMoO2(acac) and PS-LUO2X·S (where PS-LH = polymeranchored ligand; S = DMF or CH3OH; X=Cl or CH3COO- and acacH = acetylacetone). The chelating resins and complexes have been characterized by elemental analysis, IR and electronic spectra and magnetic measurements. The Cu(II), Ni(II), Co(II), and Fe(III) complexes are paramagnetic while the Zn(II), Cd(II), Mo(VI) and U(VI) complexes are diamagnetic. The IR data indicate the thioenolization of the ligand in the complexes (except in PS-LHNi(acac)2 where it behaves as a neutral bidentate ligand). (author). 24 refs., 2 tabs

  6. Chelated minerals for poultry

    Directory of Open Access Journals (Sweden)

    SL Vieira

    2008-06-01

    Full Text Available Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

  7. Rapid reductive degradation of aqueous p-nitrophenol using nanoscale zero-valent iron particles immobilized on mesoporous silica with enhanced antioxidation effect

    Science.gov (United States)

    Tang, Lin; Tang, Jing; Zeng, Guangming; Yang, Guide; Xie, Xia; Zhou, Yaoyu; Pang, Ya; Fang, Yan; Wang, Jiajia; Xiong, Weiping

    2015-04-01

    In this study, nanoscale zero-valent iron particles immobilized on mesoporous silica (nZVI/SBA-15) were successfully prepared for effective degradation of p-nitrophenol (PNP). The nZVI/SBA-15 composites were characterized by N2 adsorption/desorption, transmission electron microscopy (TEM), UV-vis spectrum and X-ray photoelectron spectroscopy (XPS). Results showed that abundant ultrasmall nanoscale zero-valent iron particles were formed and well dispersed on mesoporous silica (SBA-15). Batch experiments revealed that PNP removal declined from 96.70% to 16.14% as solution pH increased from 3.0 to 9.0. Besides, degradation equilibrium was reached within 5 min, which was independent of initial PNP concentration. Furthermore, only a little PNP elimination on SBA-15 indicated that nZVI immobilized on mesoporous silica was mainly responsible for the target contaminant removal. The UV-vis spectrum and XPS measurement confirmed that the PNP removal was a reductive degradation process, which was further proved by the detected intermediates using gas chromatography-mass spectrometry (GC/MS). The excellent antioxidation ability had been discovered with more than 80% of PNP being removed by nZVI/SBA-15 treated with 30 days' exposure to air. These results demonstrated the feasible and potential application of nZVI/SBA-15 composites in organic wastewater treatment.

  8. Examining the fixation kinetics of chelated and non-chelated copper and the applications to micronutrient management in semiarid alkaline soils

    Science.gov (United States)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.; Kusi, N. Y. O.

    2016-02-01

    This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semiarid soils of the Southern High Plains, USA, using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system compared to the chelated within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrients over time, highlighting the significance of timing even when chelated micronutrients are used. The strengths of the relationship of change in available Cu with respect to other micronutrients (iron (Fe), manganese (Mn), and zinc (Zn)) were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81), with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated system. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second-order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semiarid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  9. Efficacy of chelation therapy to remove aluminium intoxication.

    Science.gov (United States)

    Fulgenzi, Alessandro; De Giuseppe, Rachele; Bamonti, Fabrizia; Vietti, Daniele; Ferrero, Maria Elena

    2015-11-01

    There is a distinct correlation between aluminium (Al) intoxication and neurodegenerative diseases (ND). We demonstrated how patients affected by ND showing Al intoxication benefit from short-term treatment with calcium disodium ethylene diamine tetraacetic acid (EDTA) (chelation therapy). Such therapy further improved through daily treatment with the antioxidant Cellfood. In the present study we examined the efficacy of long-term treatment, using both EDTA and Cellfood. Slow intravenous treatment with the chelating agent EDTA (2 g/10 mL diluted in 500 mL physiological saline administered in 2 h) (chelation test) removed Al, which was detected (using inductively coupled plasma mass spectrometry) in urine samples collected from patients over 12 h. Patients that revealed Al intoxication (expressed in μg per g creatinine) underwent EDTA chelation therapy once a week for ten weeks, then once every two weeks for a further six or twelve months. At the end of treatment (a total of 22 or 34 chelation therapies, respectively), associated with daily assumption of Cellfood, Al levels in the urine samples were analysed. In addition, the following blood parameters were determined: homocysteine, vitamin B12, and folate, as well as the oxidative status e.g. reactive oxygen species (ROS), total antioxidant capacity (TAC), oxidized LDL (oxLDL), and glutathione. Our results showed that Al intoxication reduced significantly following EDTA and Cellfood treatment, and clinical symptoms improved. After treatment, ROS, oxLDL, and homocysteine decreased significantly, whereas vitamin B12, folate and TAC improved significantly. In conclusion, our data show the efficacy of chelation therapy associated with Cellfood in subjects affected by Al intoxication who have developed ND.

  10. Towards further understanding on the antioxidative activities of Prunus persica fruit: A comparative study with four different fractions

    Science.gov (United States)

    Dhingra, Naveen; Sharma, Rajesh; Kar, Anand

    2014-11-01

    In the present study we have evaluated the antioxidant activities of different fractions (hexane, ethyl acetate, n-butanol and aqueous fractions) of Prunus persica fruit. For extraction simple warring blender method was employed and total phenolic and flavonoid contents were correlated with different antioxidant activities (total antioxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2 scavenging, superoxide radical scavenging, iron chelating and their reducing power properties). Different in vitro antioxidant studies showed that ethyl acetate and n-butanol fractions had the maximum activities that were well correlated with total phenolic and flavonoid contents. Maximum yield (25.14 ± 2.2%) was obtained in its aqueous fraction. Both ethyl acetate and n-butanol fractions showed significant inhibitory effects on different antioxidant activities. A significantly high correlation coefficient existed between total antioxidant activities and with total phenolic as well as total flavonoid contents. It appears that ethyl acetate and n-butanol fractions of P. persica may serve as new potential sources of natural antioxidants and could be of therapeutic use in treating several diseases.

  11. Pyrrolidine dithiocarbamate inhibits UVB-induced skin inflammation and oxidative stress in hairless mice and exhibits antioxidant activity in vitro.

    Science.gov (United States)

    Ivan, Ana L M; Campanini, Marcela Z; Martinez, Renata M; Ferreira, Vitor S; Steffen, Vinicius S; Vicentini, Fabiana T M C; Vilela, Fernanda M P; Martins, Frederico S; Zarpelon, Ana C; Cunha, Thiago M; Fonseca, Maria J V; Baracat, Marcela M; Georgetti, Sandra R; Verri, Waldiceu A; Casagrande, Rúbia

    2014-09-01

    Ultraviolet B (UVB) irradiation may cause oxidative stress- and inflammation-dependent skin cancer and premature aging. Pyrrolidine dithiocarbamate (PDTC) is an antioxidant and inhibits nuclear factor-κB (NF-κB) activation. In the present study, the mechanisms of PDTC were investigated in cell free oxidant/antioxidant assays, in vivo UVB irradiation in hairless mice and UVB-induced NFκB activation in keratinocytes. PDTC presented the ability to scavenge 2,2'-azinobis-(3-ethyl benzothiazoline-6-sulfonic acid) radical (ABTS), 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH) and hydroxyl radical (OH); and also efficiently inhibited iron-dependent and -independent lipid peroxidation as well as chelated iron. In vivo, PDTC treatment significantly decreased UVB-induced skin edema, myeloperoxidase (MPO) activity, production of the proinflammatory cytokine interleukin-1β (IL-1β), matrix metalloproteinase-9 (MMP-9), increase of reduced glutathione (GSH) levels and antioxidant capacity of the skin tested by the ferric reducing antioxidant power (FRAP) and ABTS assays. PDTC also reduced UVB-induced IκB degradation in keratinocytes. These results demonstrate that PDTC presents antioxidant and anti-inflammatory effects in vitro, which line up well with the PDTC inhibition of UVB irradiation-induced skin inflammation and oxidative stress in mice. These data suggest that treatment with PDTC may be a promising approach to reduce UVB irradiation-induced skin damages and merits further pre-clinical and clinical studies.

  12. Role of antioxidant enzymes in bacterial resistance to organic acids.

    Science.gov (United States)

    Bruno-Bárcena, Jose M; Azcárate-Peril, M Andrea; Hassan, Hosni M

    2010-05-01

    Growth in aerobic environments has been shown to generate reactive oxygen species (ROS) and to cause oxidative stress in most organisms. Antioxidant enzymes (i.e., superoxide dismutases and hydroperoxidases) and DNA repair mechanisms provide protection against ROS. Acid stress has been shown to be associated with the induction of Mn superoxide dismutase (MnSOD) in Lactococcus lactis and Staphylococcus aureus. However, the relationship between acid stress and oxidative stress is not well understood. In the present study, we showed that mutations in the gene coding for MnSOD (sodA) increased the toxicity of lactic acid at pH 3.5 in Streptococcus thermophilus. The inclusion of the iron chelators 2,2'-dipyridyl (DIP), diethienetriamine-pentaacetic acid (DTPA), and O-phenanthroline (O-Phe) provided partial protection against 330 mM lactic acid at pH 3.5. The results suggested that acid stress triggers an iron-mediated oxidative stress that can be ameliorated by MnSOD and iron chelators. These findings were further validated in Escherichia coli strains lacking both MnSOD and iron SOD (FeSOD) but expressing a heterologous MnSOD from S. thermophilus. We also found that, in E. coli, FeSOD did not provide the same protection afforded by MnSOD and that hydroperoxidases are equally important in protecting the cells against acid stress. These findings may explain the ability of some microorganisms to survive better in acidified environments, as in acid foods, during fermentation and accumulation of lactic acid or during passage through the low pH of the stomach. PMID:20305033

  13. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    Directory of Open Access Journals (Sweden)

    Leonardo Martinez-Cardenas

    2011-09-01

    Full Text Available Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a β-carotene-linoleic acid emulsion, and iron (II chelation, the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II-dependent hydroxyl radicals (OH•, in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p < 0.05 and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05 to the concentration of total phenolic compounds (R2 = 0.90 and ascorbic acid (R2 = 0.86. All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•.

  14. Antioxidant activity of leaves and inflorescence of Eryngium Caucasicum Trautv at flowering stage

    Directory of Open Access Journals (Sweden)

    Mohamamd Ali Ebrahimzadeh

    2009-01-01

    Full Text Available Methanol extracts of leaves and inflorescence of Eryngium Caucasicum Trautv at flowering stage were investigated for their antioxidant activities employing six in vitro assay systems, i.e. DPPH and nitric oxide radical scavenging, reducing power, linoleic acid and iron ion chelating power. IC50 for DPPH radical-scavenging activity was 0.15 ± 0.01 for leaves and 0.39 ± 0.02 mg ml−1 for inflorescence. Reducing powers of both extracts increased with the increase of their concentrations. Leaves extract showed better activity than Vitamin C (p< 0.05. Extracts showed weak nitric oxide-scavenging activity. Leaves extract exhibited better Fe2+ chelating ability (IC50=0.25 mg ml−1 that was comparable with EDTA. (IC50=18 ìg ml−1. Inflorescence extracts had shown a very weak activity. Extracts showed very good scavenging activity of H2O2. IC50 was 25.5 ± 1.3 for leaves and 177.2 ± 11.6 mg ml−1 for inflorescence, respectively. No antioxidant activity exhibited in linoleic acid test. Extracts exhibited different levels of antioxidant activity in all the models studied.

  15. In Vitro Ion Chelating, Antioxidative Mechanism of Extracts from Fruits and Barks of Tetrapleura tetraptera and Their Protective Effects against Fenton Mediated Toxicity of Metal Ions on Liver Homogenates

    Directory of Open Access Journals (Sweden)

    Bruno Moukette Moukette

    2015-01-01

    Full Text Available The aim of the present study was to investigate the antioxidant activity and protective potential of T. tetraptera extracts against ion toxicity. The antioxidant activity of the extracts was investigated spectrophotometrically against several radicals (1,1-diphenyl-2-picrylhydrazyl (DPPH•, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS•, hydroxyl radical (HO•, and nitric oxide (NO•, followed by the ferric reducing power, total phenols, flavonoid, and flavonol contents. The effects of the extracts on catalase (CAT, superoxide dismutase (SOD, and peroxidase activities were also determined using the standard methods as well as the polyphenol profile using HPLC. The results showed that the hydroethanolic extract of T. tetraptera (CFH has the lowest IC50 value with the DPPH, ABTS, OH, and NO radicals. The same extract also exhibited the significantly higher level of total phenols (37.24 ± 2.00 CAE/g dried extract; flavonoids (11.36 ± 1.88 QE/g dried extract; and flavonols contents (3.95 ± 0.39 QE/g dried extract. The HPLC profile of T. tetraptera revealed that eugenol (958.81 ± 00 mg/g DW, quercetin (353.78 ± 00 mg/g DW, and rutin (210.54 ± 00 mg/g DW were higher in the fruit than the bark extracts. In conclusion, extracts from T. tetraptera may act as a protector against oxidative mediated ion toxicity.

  16. Subclinical renal abnormalities in young thalassemia major and intermedia patients and its relation to chelation therapy

    OpenAIRE

    Adly, Amira A.M.; Dalia N. Toaima; Noha Refaat Mohamed; Karim Mahmoud Abu El Seoud

    2014-01-01

    Background: Limited data are available about renal involvement in thalassemia patients. Renal dysfunction in these patients seems to be multifactorial attributed mainly to long standing anemia, chronic hypoxia, iron overload and toxicity of iron chelators. Objective: To assess the frequency of subclinical glomerular and tubular dysfunctions in children and adolescents with β-thalassemia major and intermedia, and to correlate these findings with the degree of iron overload and type of chela...

  17. Fortification Iron as Ferrous Sulfate Plus Ascorbic Acid Is More Rapidly Absorbed Than as Sodium Iron EDTA but Neither Increases Serum Nontransferrin-Bound Iron in Women

    NARCIS (Netherlands)

    Troesch, B.; Egli, I.; Zeder, C.; Hurrell, R.F.; Zimmermann, M.B.

    2011-01-01

    The absorption profile of iron fortificants may be a determinant of their ability to generate nontransferrin-bound iron (NTBI) and, thus, their potential safety. Ferrous iron may be absorbed more rapidly than chelated ferric iron, but differences at the fortification level cannot be distinguished wi

  18. Potential Anticancer Properties of Grape Antioxidants

    OpenAIRE

    Kequan Zhou; Raffoul, Julian J.

    2012-01-01

    Dietary intake of foods rich in antioxidant properties is suggested to be cancer protective. Foods rich in antioxidant properties include grape (Vitis vinifera), one of the world's largest fruit crops and most commonly consumed fruits in the world. The composition and cancer-protective effects of major phenolic antioxidants in grape skin and seed extracts are discussed in this review. Grape skin and seed extracts exert strong free radical scavenging and chelating activities and inhibit lipid ...

  19. In vitro antioxidant and anti-inflammatory properties of Limonium algarvense flowers' infusions and decoctions: A comparison with green tea (Camellia sinensis).

    Science.gov (United States)

    Rodrigues, Maria João; Neves, Vanessa; Martins, Alice; Rauter, Amélia P; Neng, Nuno R; Nogueira, José M F; Varela, João; Barreira, Luísa; Custódio, Luísa

    2016-06-01

    This work reports the in vitro antioxidant and anti-inflammatory activities and toxicity of infusions and decoctions of Limonium algarvense flowers, and green tea. The total contents in different phenolic groups and the quantification of individual phenolics by HPLC are also reported. L. algarvense and green tea had similar antioxidant properties, except for hydroxyl radical-scavenging activity, higher on green tea, and iron chelating potential, higher on L. algarvense. The later species also had the uppermost anti-inflammatory potential. Green tea decoction had the highest content of phenolic groups, but the infusion of L. algarvense had higher amounts of salicylic, gallic and coumaric acids. L. algarvense was not toxic, whereas green tea was toxic for S17 cells. Under our experimental conditions, infusions and decoctions of L. algarvense flowers had similar or higher antioxidant and anti-inflammatory properties than green tea, and thus, may be useful for alleviating symptoms associated with oxidative and inflammatory-related diseases.

  20. Intestinal Iron Homeostasis and Colon Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Yatrik M. Shah

    2013-06-01

    Full Text Available Colorectal cancer (CRC is the third most common cause of cancer-related deaths in industrialized countries. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Iron is an essential nutrient for cell growth. Iron overload caused by hereditary mutations or excess dietary iron uptake has been identified as a risk factor for CRC. Intestinal iron is tightly controlled by iron transporters that are responsible for iron uptake, distribution, and export. Dysregulation of intestinal iron transporters are observed in CRC and lead to iron accumulation in tumors. Intratumoral iron results in oxidative stress, lipid peroxidation, protein modification and DNA damage with consequent promotion of oncogene activation. In addition, excess iron in intestinal tumors may lead to increase in tumor-elicited inflammation and tumor growth. Limiting intratumoral iron through specifically chelating excess intestinal iron or modulating activities of iron transporter may be an attractive therapeutic target for CRC.

  1. Mineral Components and Anti-oxidant Activities of Tropical Seaweeds

    Institute of Scientific and Technical Information of China (English)

    Suzuki Takeshi; Yoshie-Stark Yumiko; Santoso Joko

    2005-01-01

    Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography (HPLC); the anti-oxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocatechin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control,and that of a green alga shows the strongest anti-oxidant activity. The highest chelation on ferrous ions is also found in the extract of this alga, which is significantly different from the other methanol extracts in both 3 and 24 h incubations.

  2. Design and Synthesis of Some New 1,3,4-Thiadiazines with Coumarin Moieties and Their Antioxidative and Antifungal Activity

    Directory of Open Access Journals (Sweden)

    Milan Čačić

    2014-01-01

    Full Text Available A series of newly disubstituted (compounds 4a,b and trisubstituted 1,3,4-thiadiazines 5a–l with various substituents was prepared utilizing different thiosemicarbazides and 3-α-bromoacetylcoumarins as starting compounds. The structures of the synthesized 1,3,4-thiadiazines are elucidated and confirmed utilizing the corresponding analytical and spectroscopic data. All of the new thiadiazine derivatives were tested for their antioxidant activity, employing different antioxidant assays (DPPH scavenging activity, iron chelating activity, power reducing activity. Compounds 5b, 5f, 5j and 4b were proven to be the best DPPH radical scavengers, while compounds 5h and 5j have shown the best iron chelating activity. Thiadiazine derivatives were also tested on their antifungal activity against four mycotoxicogenic fungi, Aspergillus flavus, A. ochraceus, Fusarium graminearum and F. verticillioides. The best antifungal against A. flavus was proven to be compound 5e, while compounds 4a and 5c were the best antifungals on A. ochraceus, and compound 5g showed the best antifungal activity on F. verticillioides.

  3. Antioxidant Activities of Aqueous Extract from Cultivated Fruit-bodies of Cordyceps militaris (L.) Link In Vitro

    Institute of Scientific and Technical Information of China (English)

    Yu Zhan; Cai-Hong Dong; Yi-Jian Yao

    2006-01-01

    Biological antioxidants extracted from plants and fungi have potential abilities to scavenge free radicals and inhibit lipid peroxidation, playing important roles in preventing diseases, for example, cancer, and aging induced by reactive oxygen species, which may cause oxidative damage to DNA, proteins and other macromolecules. The antioxidant potency of cultivated fruit-bodies of Cordyceps militaris (L.) Link was investigated in this study. Five established in vitro systems were employed, including the 1,1-diphenyl-2-picryldrazyl (DPPH) free radical scavenging, hydroxyl radical eliminating, iron chelating, inhibition of linoleic acid lipid peroxidation and reducing power. The aqueous extract from cultivated fruit-bodies was subjected to the test of amino acid, polysaccharide and mannitol. Ascorbic acid (Vc), butylated hydroxytoluene (BHT)and ethylenediaminetetraacetic acid (EDTA) were used as positive controls for comparisons. Among the assays, the aqueous extract of C. militaris fruit-bodies shows a significant scavenging effect on DPPH,eliminating the capability on hydroxyl radicals and the chelating effect on ferrous iron. The extract also shows positive results of inhibiting linoleic acid lipid peroxidation and reducing power.

  4. Emulsifier type, metal chelation and pH affect oxidative stability of n-3-enriched emulsions

    DEFF Research Database (Denmark)

    Haahr, Anne-Mette; Jacobsen, Charlotte

    2008-01-01

    Recent research has shown that the oxidative stability of oil-in-water emulsions is affected by the type of surfactant used as emulsifier. The aim of this study was to evaluate the effect of real food emulsifiers as well as metal chelation by EDTA and pH on the oxidative stability of a 10% n-3...... to their ability to chelate iron, scavenge free radicals, interfere with interactions between the lipid hydroperoxides and iron as well as to form a physical harrier around the oil droplets....

  5. Removal of cadmium from fish sauce using chelate resin.

    Science.gov (United States)

    Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

    2015-04-15

    Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities.

  6. Acquisition, Transport, and Storage of Iron by Pathogenic Fungi

    OpenAIRE

    Howard, Dexter H.

    1999-01-01

    Iron is required by most living systems. A great variety of means of acquisition, avenues of uptake, and methods of storage are used by pathogenic fungi to ensure a supply of the essential metal. Solubilization of insoluble iron polymers is the first step in iron assimilation. The two methods most commonly used by microorganisms for solubilization of iron are reduction and chelation. Reduction of ferric iron to ferrous iron by enzymatic or nonenzymatic means is a common mechanism among pathog...

  7. Investigation of in vitro cytotoxicity of the redox state of ionic iron in neuroblastoma cells

    Directory of Open Access Journals (Sweden)

    Ajay Vikram Singh

    2012-01-01

    Full Text Available Background: there is an intimate relation between transition metals and cell homeostasis due to the physiological necessity of metals in vivo. Particularly, iron (ferrous and ferric state is utilized in many physiological processes of the cell but in excess has been linked with negative role contributing in many neurodegenerative processes. Objective: the aim of this study was to investigate which oxidation state of ionic iron (Ferrous (II versus Ferric (III is more toxic to neuronal cells (SHSY5Y. Materials and Methods: The neuroblastoma (SHSY5Y cells were exposed to varying concentration of ferric and ferrous iron. Morphological studies using immunofluorescence staining and microscopic analysis as confirmed by intracellular glutathione (GSH test demonstrated oxidative stress to cells in iron microenvironment. In addition, MTT assay was performed to evaluate the viability and metabolic state of the cells. Results: the results showed that ferrous form has significantly higher toxicity compared to the ferric ionic state of higher concentration. In addition, microscopic analysis shows cell fenestration at higher concentrations and swelling at intermediate ferric dosages as demonstrated by atomic force microscopy (AFM. Interestingly, the addition of a differentiation inducing factor, trans-retinoic rcid (RA retains significant viability and morphological features of the cells irrespective of the ionic state of the iron. AFM images revealed clustered aggregates arising from iron chelation with RA. Conclusions: the results indicate that Fe (II has more toxic effects on cells. In addition, it could be an interesting finding with respect to the antioxidant properties of RA as a chelating agent for the neurodegenerative therapeutics.

  8. (+/-)-catechin: chemical weapon, antioxidant, or stress regulator?

    Science.gov (United States)

    Chobot, Vladimir; Huber, Christoph; Trettenhahn, Guenter; Hadacek, Franz

    2009-08-01

    (+/-)-Catechin is a flavan-3-ol that occurs in the organs of many plant species, especially fruits. Health-beneficial effects have been studied extensively, and notable toxic effects have not been found. In contrast, (+/-)-catechin has been implicated as a 'chemical weapon' that is exuded by the roots of Centaurea stoebe, an invasive knapweed of northern America. Recently, this hypothesis has been rejected based on (+/-)-catechin's low phytotoxicity, instability at pH levels higher than 5, and poor recovery from soil. In the current study, (+/-)-catechin did not inhibit the development of white and black mustard to an extent that was comparable to the highly phytotoxic juglone, a naphthoquinone that is allegedly responsible for the allelopathy of the walnut tree. At high stress levels, caused by sub-lethal methanol concentrations in the medium, and a 12 h photoperiod, (+/-)-catechin even attenuated growth retardation. A similar effect was observed when (+/-)-catechin was assayed for brine shrimp mortality. Higher concentrations reduced the mortality caused by toxic concentrations of methanol. Further, when (+/-)-catechin was tested in variants of the deoxyribose degradation assay, it was an efficient scavenger of reactive oxygen species (ROS) when they were present in higher concentrations. This antioxidant effect was enhanced when iron was chelated directly by (+/-)-catechin. Conversely, if iron was chelated to EDTA, pro-oxidative effects were demonstrated at higher concentrations; in this case (+/-)-catechin reduced molecular oxygen and iron to reagents required by the Fenton reaction to produce hydroxyl radicals. A comparison of cyclic voltammograms of (+/-)-catechin with the phytotoxic naphthoquinone juglone indicated similar redox-cycling properties for both compounds although juglone required lower electrochemical potentials to enter redox reactions. In buffer solutions, (+/-)-catechin remained stable at pH 3.6 (vacuole) and decomposed at pH 7.4 (cytoplasm

  9. Phytases for Improved Iron Absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Nyffenegger, Christian; Meyer, Anne S.

    2014-01-01

    Microbial phytases (EC 3.1.3.8) catalyse dephosphorylation of phytic acid, which is the primary storage compound for phosphorous in cereal kernels. The negatively charged phosphates in phytic acid chelate iron (Fe3+) and thus retards iron bioavailability in humans 1. Supplementation of microbial...... phytase can improve iron absorption from cereal-based diets 2. In order for phytase to catalyse iron release in vivo the phytase must be robust to low pH and proteolysis in the gastric ventricle. Our work has compared the robustness of five different microbial phytases, evaluating thermal stability...

  10. Iron-binding properties of sugar cane yeast peptides.

    Science.gov (United States)

    de la Hoz, Lucia; Ponezi, Alexandre N; Milani, Raquel F; Nunes da Silva, Vera S; Sonia de Souza, A; Bertoldo-Pacheco, Maria Teresa

    2014-01-01

    The extract of sugar-cane yeast (Saccharomyces cerevisiae) was enzymatically hydrolysed by Alcalase, Protex or Viscozyme. Hydrolysates were fractionated using a membrane ultrafiltration system and peptides smaller than 5kDa were evaluated for iron chelating ability through measurements of iron solubility, binding capacity and dialyzability. Iron-chelating peptides were isolated using immobilized metal affinity chromatography (IMAC). They showed higher content of His, Lys, and Arg than the original hydrolysates. In spite of poor iron solubility, hydrolysates of Viscozyme provided higher iron dialyzability than those of other enzymes. This means that more chelates of iron or complexes were formed and these kept the iron stable during simulated gastro-intestinal digestion in vitro, improving its dialyzability.

  11. Selective separation of indium by iminodiacetic acid chelating resin

    Energy Technology Data Exchange (ETDEWEB)

    Fortes, M.C.B.; Benedetto, J.S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Martins, A.H. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica e de Materiais]. E-mail: ahmartin@demet.ufmg.br

    2007-04-15

    - Indium can be recovered by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting. This paper investigates the adsorption characteristics of indium and iron on an iminodiacetic acid chelating resin, Amberlite{sup R} IRC748 (Rohm and Haas Co.-USA). High concentrations of iron are always present in the aqueous feed solution of indium recovery. In addition, the chemical behaviour of iron in adsorptive systems is similar to that of indium. The metal concentrations in the aqueous solution were based on typical indium sulfate leach liquor obtained from zinc hydrometallurgical processing in a Brazilian plant. The ionic adsorption experiments were carried out by the continuous column method. Amberlite{sup R} IRC748 resin had a high affinity for indium under acidic conditions. Indium ions adsorbed onto the polymeric resin were eluted with a 0.5 mol/dm{sup 3} sulphuric acid solution passed through the resin bed in the column. 99.5% pure indium sulfate aqueous solution was obtained using the iminodiacetic acid chelating resin Amberlite{sup R} IRC748. (author)

  12. Antioxidant activity of hydroalcoholic leaf extracts of Psidium guajava and Persea Americana, an invitro study

    International Nuclear Information System (INIS)

    Ionizing radiation produce deleterious effects in the living organisms. Rapid technological advancement has increased human exposure to ionizing radiations enormously. Several plants have been screened for their radio protective ability and the hunt for identifying many more safe, nontoxic and effective ones is in progress. The aim of the present study was to evaluate the antioxidant activity in hydro alcoholic leaf extract of Psidium guajava (guava) and Persea americana (avocado). The antioxidant assay such as 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) free radical scavenging assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, chelation of iron by plant extract, hydroxyl radical scavenging assay, ferric reducing antioxidant potential (FRAP), and total antioxidant activity of extract was analyzed using spectrophotometer. Phytochemical screening and HPLC analysis of leaf extracts were also performed. The results indicated that the IC50 value of hydro alcoholic leaf extract of P.guajava and P. americana were 14 μg/ml and 15 μg/ml in ABTS free radical scavenging assay, 4 μg/ml and 2.5 μg/ml in DPPH free radical scavenging assay, 7.2 μg/ml and 8.4 μg/ml in chelation of iron by plant extract, 2 μg/ml and, 4.3 μg/ml in hydroxyl radical scavenging assay and effective concentration(EC50) was 57.80 μg/ml and 87.56 μg/ml in FRAP assay respectively. The results for total antioxidant activity indicated that 242.3 μg/ml of P.guajava and 432.7 μg/ml of P.americana extract was equivalent to 100 μg/ml of standard qurecetin respectively. Qualitative analysis of hydroalcoholic leaf extracts revealed the presence of flavonoids, tannins, saponions, terpenoids, and glycosides. HPLC analysis confirmed the presence of flavonoids qurecetin and rutin in leaf extracts on comparison with standard compounds. Our study showed that hydro alcoholic leaf extracts of Psidium guajava and Persea americana act as strong antioxidant and free

  13. Antioxidant activities of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey

    OpenAIRE

    Özen, Tevfik; TÜRKEKUL, İbrahim

    2010-01-01

    The antioxidant activities of the methanol extract of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey were investigated in this study. Antioxidant activities were evaluated in terms of total antioxidant activity, reducing power, metal chelating ability, inhibition of linoleic acid peroxidation, superoxide, peroxide and hydrogen peroxide scavenging effects. Various antioxidant activities were compared to references antioxidants such as α-tocopherol, butylated hydroxyanisole ...

  14. Antioxidant activities of Sarcodon imbricatum wildly grown in the black sea region of Turkey

    OpenAIRE

    Tevfik Ozen; Ibrahim Turkekul

    2010-01-01

    The antioxidant activities of the methanol extract of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey were investigated in this study. Antioxidant activities were evaluated in terms of total antioxidant activity, reducing power, metal chelating ability, inhibition of linoleic acid peroxidation, superoxide, peroxide and hydrogen peroxide scavenging effects. Various antioxidant activities were compared to references antioxidants such as α-tocopherol, butylated hydroxyanisole ...

  15. Essential trace metal excretion from rats with lead exposure and during chelation therapy.

    Science.gov (United States)

    Victery, W; Miller, C R; Goyer, R A

    1986-02-01

    Urinary excretion of lead, zinc, calcium, magnesium, iron, copper, sodium, and potassium was measured in rats daily for 1 week after a 6-week exposure to 10,000 micrograms/ml lead in drinking water. Beginning on the third day, half of the lead-exposed and control rats were injected intraperitoneally with calcium disodium ethylenediaminetetraacetate (EDTA) daily for 3 days. Whole blood, plasma, and kidney metal concentrations were determined from samples obtained at the end of the experiment. Exposure to lead increased urinary excretion, not only of lead, but also of calcium, magnesium, zinc, copper, and iron. Excretion of sodium and potassium was not altered. Chelation therapy further increased excretion of lead, zinc, copper, and iron, but not magnesium. The increase in calcium excretion during chelation treatment (beyond that resulting from lead exposure per se) was accounted for by the Ca content of CaNa2-EDTA. EDTA treatment increased renal concentration of zinc but lowered renal concentration of lead, copper, and iron. These multimetal alterations may have implications for essential metal supplementation, particularly zinc, in persons being given chelation agents for excess lead exposure and in infants and children with low-level lead exposure not necessarily requiring chelation therapy.

  16. Iron and Acinetobacter baumannii Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Valentina Gentile

    2014-08-01

    Full Text Available Acinetobacter baumannii is an emerging nosocomial pathogen, responsible for infection outbreaks worldwide. The pathogenicity of this bacterium is mainly due to its multidrug-resistance and ability to form biofilm on abiotic surfaces, which facilitate long-term persistence in the hospital setting. Given the crucial role of iron in A. baumannii nutrition and pathogenicity, iron metabolism has been considered as a possible target for chelation-based antibacterial chemotherapy. In this study, we investigated the effect of iron restriction on A. baumannii growth and biofilm formation using different iron chelators and culture conditions. We report substantial inter-strain variability and growth medium-dependence for biofilm formation by A. baumannii isolates from veterinary and clinical sources. Neither planktonic nor biofilm growth of A. baumannii was affected by exogenous chelators. Biofilm formation was either stimulated by iron or not responsive to iron in the majority of isolates tested, indicating that iron starvation is not sensed as an overall biofilm-inducing stimulus by A. baumannii. The impressive iron withholding capacity of this bacterium should be taken into account for future development of chelation-based antimicrobial and anti-biofilm therapies.

  17. Luminescent lanthanide chelates and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Selvin, Paul R. (Berkeley, CA); Hearst, John (Berkeley, CA)

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  18. Chelators for investigating zinc metalloneurochemistry.

    Science.gov (United States)

    Radford, Robert J; Lippard, Stephen J

    2013-04-01

    The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals of hippocampal mossy fiber buttons.

  19. Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

    Institute of Scientific and Technical Information of China (English)

    张永清; 谢晓芳; 黄少斌; 梁海云

    2014-01-01

    In the interest of accelerating aniline degradation, Fe2+and chelated Fe2+activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate (EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn’t follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

  20. Antioxidant ability and mechanism of rhizoma Atractylodes macrocephala.

    Science.gov (United States)

    Li, Xican; Lin, Jian; Han, Weijuan; Mai, Wenqiong; Wang, Li; Li, Qiang; Lin, Miaofang; Bai, Mingsong; Zhang, Lishan; Chen, Dongfeng

    2012-01-01

    Rhizoma Atractylodes macrocephala (AM) has been used in Traditional Chinese Medicine (TCM) for about 2,000 years. In the study, we firstly determined the antioxidant levels of five AM extracts by •OH-scavenging, •O2−-scavenging, Fe2+-chelating, Cu2+-chelating, DPPH·-scavenging, and ABTS+·-scavenging assays. After measurement of the chemical contents in five AM extracts, we quantitatively analyzed the correlations between antioxidant levels and chemical contents. It was observed that total phenolics and total flavonoids had significant positive correlations with antioxidant levels (R = 0.685 and 0.479, respectively). In contrast, total sugars and total saponins presented lower correlations with antioxidant levels (R=−0.272 and 0.244, respectively). It means that antioxidant activity of AM should be attributed to total phenolics (including phenolic acids and flavonoids), and not total sugars and total saponins. Further analysis indicated that phenolic acids exhibited higher R values with radical-scavenging assays (R=0.32–1.00), while flavonoids showed higher R values with metal-chelating assays (R=0.86 and 0.90). In conclusion, AM exerts its antioxidant effect through metal-chelating, and radical-scavenging which is via donating hydrogen atom and donating electron. Its metal-chelating may result from flavonoids, while its radical-scavenging can be attributed to phenolic acids, especially caffeic acid, ferulic acid, and protocatechuic acid. PMID:23149564

  1. Impacto da farinha de mandioca fortificada com ferro aminoácido quelato no nível de hemoglobina de pré-escolares Impact of cassava flour fortified with iron amino acid chelate on the hemoglobin level in pre-schools

    Directory of Open Access Journals (Sweden)

    Rahilda Brito Tuma

    2003-01-01

    Full Text Available OBJETIVO: Avaliou-se o impacto da farinha de mandioca fortificada com ferro aminoácido quelato em 80 pré-escolares de uma Unidade Filantrópica de Manaus, AM, distribuídos aleatoriamente em quatro grupos de 20 crianças cada, por um período de 120 dias. MÉTODOS: Foram utilizadas farinha de mandioca sem fortificação (Grupo zero e fortificada com 1, 2 e 3mg de Fe/dia, correspondendo a quantias diárias de 5, 10 e 15g de farinha, respectivamente, as quais foram distribuídas no horário do almoço, sendo ainda entregue às famílias a quantidade destinada ao consumo do final de semana. O estado nutricional das crianças foi avaliado no início e ao final do experimento, adotando-se como limite discriminatório entre eutrofia/desnutrição o ponto de corte OBJECTIVE: The impact of the cassava flour fortified with iron amino acid chelate was evaluated in 80 pre-scholars of a Philanthropic Unit of Manaus, state of Amazonas, randomly distributed in four groups of 20 children each, for a period of 120 days. METHODS: Cassava flour was used without fortification (group zero or fortified with 1, 2 and 3mg of Fe/day, corresponding respectively to 5, 10 and 15g of flour/day, which were given to the children at lunch time on weekdays. The equivalent amount was previously distributed to their families for flour intake also during the weekends. In the beginning and at the end of the experiment the children's nutritional status was evaluated, being adopted the cutoff point <-2 Z-scores as a discriminating limit between eutrophy/malnutrition, in agreement with the World Health Organization criteria, as well as being established as a cutoff point for the occurrence of iron deficiency anemia a hemoglobin rate of less than 11g/dL. RESULTS: At the end of this study, children recovered from chronic malnutrition, and a significant increase (p <5% of the hemoglobin rates, independently of iron concentration, from 11.4±0.9g/dL to 12.2±0.8g/dL, was observed in

  2. Antioxidant properties of some plants growing wild in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Serteser, A.; Kargioglu, M.; Gok, V.; Bagci, Y.; Musa Ozcan, M.; Arslan, D.

    2009-07-01

    In this study, the antioxidant activity of 50% aqueous methanol extracts of 38 plants growing in the Afyonkarahisar province of Turkey were evaluated by various antioxidant assay, including free radical scavenging, hydrogen peroxide (H{sub 2}O{sub 2}) scavenging and metal (Fe{sup 2}+) chelating activities. The methanolic fruit extracts of the Cornus and Morus species (H{sub 2}O{sub 2} and DPPH scavenging activities, Fe{sup 2}+ chelating activity) and the methanolic leaf extracts of the Mentha species (DPPH scavenging activities) examined in the assay showed the strongest activities. These antioxidant properties depended on the concentration of samples. (Author) 30 refs.

  3. Antioxidant properties of various solvent extracts from purple basil

    Science.gov (United States)

    Yeşiloğlu, Yeşim; Şit, Latifşah

    2012-09-01

    Water, ethanol and acetone extracts from leaves and flowers of purple basil, one of the most popular spices consumed in the Thrace region of Turkey, were tested in vitro for their ability to inhibit peroxidation of lipids, to scavenge DPPH, hydrogen peroxide, superoxide anion, to reduce Fe(III) to Fe(II) and to chelate Fe(II) ions. The results showed that purple basil contained naturally occurring antioxidant components and possessed antioxidant activity which may be attributed to its lipid peroxidation inhibitory, radical scavenging and metal chelating activities. It was concluded that purple basil might be a potential source of antioxidants.

  4. Iron and Iron Metabolism

    OpenAIRE

    Melike Sezgin Evim; Birol Baytan; Adalet Meral Güneş

    2012-01-01

    Iron is an essential element for almost all living organisms except some bacteria. A great number of new articles related to the iron metabolism have been published in recent years explaining new findings. Hepsidine, a peptide hormon, that is recently found, regulates iron methabolism by effecting iron absorbsion from gut, secreting iron from hepatic store and flows iron from macrophages. Hepsidin blockes to effluxe iron from cells by bounding to ferroportin and by inducing ferroportin destru...

  5. ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

    Directory of Open Access Journals (Sweden)

    Anna Skoczyńska

    2010-09-01

    Full Text Available Background: Exposure to heavy metals leads to functional and metabolic disturbances and many of them are included in pathogenesis of common diseases (arterial hypertension, atherosclerosis, neurodegenerative processes. In this context new therapeutic and prophylactic strategies are necessary. Patients diagnosed with chronic heavy metals intoxication usually require chelation to increase mobilisation of metals from tissues and elimination of them via urine. Acute poisoning with toxic metal may be difficult to diagnosis, especially in case of accidental intoxication or suicidal intention. Patients also require chelation after causative factor is identified. Objectives: To describe some problems connected with toxicity of metals poisoning and to review pharmacologic therapies that could have a role in poisoning with metals. Methods: A review of the literature was carried out and expert opinion expressed. Results/conclusion: Chelation is a common therapy in case of poisoning with toxic metals but it is satisfied only partially. A combined therapy with structurally different chelators or long-term acting chelators could become viable alternatives in the future. A combined therapy with an antioxidant plus chelator may be a good choice in patients chronically poisoned with metals. Exposure to lead should be taken into account during estimation of global cardiovascular risk.

  6. Iron Oxide Nanoparticles as a Potential Iron Fertilizer for Peanut (Arachis hypogaea)

    Science.gov (United States)

    Rui, Mengmeng; Ma, Chuanxin; Hao, Yi; Guo, Jing; Rui, Yukui; Tang, Xinlian; Zhao, Qi; Fan, Xing; Zhang, Zetian; Hou, Tianqi; Zhu, Siyuan

    2016-01-01

    Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of iron oxide nanoparticles (Fe2O3 NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe2O3 NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe2O3 NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe2O3 NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe2O3 NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe2O3 NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe2O3 NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe2O3 NPs as the iron fertilizer. PMID:27375665

  7. Sequence diversity and enzyme activity of ferric-chelate reductase LeFRO1 in tomato.

    Science.gov (United States)

    Kong, Danyu; Chen, Chunlin; Wu, Huilan; Li, Ye; Li, Junming; Ling, Hong-Qing

    2013-11-20

    Ferric-chelate reductase which functions in the reduction of ferric to ferrous iron on root surface is a critical protein for iron homeostasis in strategy I plants. LeFRO1 is a major ferric-chelate reductase involved in iron uptake in tomato. To identify the natural variations of LeFRO1 and to assess their effect on the ferric-chelate reductase activity, we cloned the coding sequences of LeFRO1 from 16 tomato varieties collected from different regions, and detected three types of LeFRO1 (LeFRO1(MM), LeFRO1(Ailsa) and LeFRO1(Monita)) with five amino acid variations at the positions 21, 24, 112, 195 and 582. Enzyme activity assay revealed that the three types of LeFRO1 possessed different ferric-chelate reductase activity (LeFRO1(Ailsa) > LeFRO1(MM) > LeFRO1(Monita)). The 112th amino acid residue Ala of LeFRO1 is critical for maintaining the high activity of ferric-chelate reductase, because modification of this amino acid resulted in a significant reduction of enzyme activity. Further, we showed that the combination of the amino acid residue Ile at the site 24 with Lys at the site 582 played a positive role in the enzyme activity of LeFRO1. In conclusion, the findings are helpful to understand the natural adaptation mechanisms of plants to iron-limiting stress, and may provide new knowledge to select and manipulate LeFRO1 for improving the iron deficiency tolerance in tomato.

  8. (Dithiocarbamato)iron(II) complexes: Photochemical chelation and ligand exchange, comparison with electron-transfer processes, and X-ray crystal structures of Fe(. eta. sup 5 -C sub 5 Me sub 5 )(. eta. sup 1 -SC(S)NMe sub 2 )(CO) sub 2 and Fe(. eta. sup 5 -C sub 5 Me sub 5 )(. eta. sup 2 -S sub 2 CNMe sub 2 )(PPh sub 3 )

    Energy Technology Data Exchange (ETDEWEB)

    Desbois, M.H.; Astruc, D. (Universite de Bordeaux I, Talence (France)); Nunn, C.M.; Cowley, A.H. (Univ. of Texas, Austin (USA))

    1990-03-01

    The X-ray crystal structure of FeCp{sup *}({eta}{sup 1}-dtc)(CO){sub 2} (1, Cp{sup *} = {eta}{sup 5}-C{sub 5}Me{sub 5}, dtc = S{sub 2}CNMe{sub 2}) confirms that the dithiocarbamate ligand is bound to iron in a monodentate mode. The photochemical chelation of 1 is carried out in dichloromethane using visible light and quantitatively gives the chelate FeCp{sup *}({eta}{sup 2}-dtc)(CO) (2) and CO. This reaction is the best route to 2 and compares with the electron-transfer chain (ETC) processes 1 {yields} 2 catalyzed by either oxidizing or reducing agents. The photolytic reaction, which can be carried out by monochromatic (330 nm) irradiation and monitored by visible spectroscopy, gives to isosbestic points at 394 and 432 nm. Both complexes 1 and 3 crystallize in a triclinic system. 1: a = 8.582 (2) {angstrom}, b = 9.046 (4) {angstrom}, c = 12.377 (7) {angstrom}, {alpha} = 97.05 (4){degree}, {beta} = 96.84 (3){degree}, {gamma} = 111.99 (3){degree}, space group P{bar 1}, Z = 2. 3: a = 11.142 (4) {angstrom}, b = 14.958 (4) {angstrom}, c = 10.382 (4) {angstrom}, {alpha} = 98.22 (2){degree}, {beta} = 115.22 (3){degree}, {gamma} 102.62 (3){degree}, space group P{bar 1}, Z = 2.

  9. Antioxidants protect keratinocytes against M. ulcerans mycolactone cytotoxicity.

    Directory of Open Access Journals (Sweden)

    Alvar Grönberg

    Full Text Available BACKGROUND: Mycobacterium ulcerans is the causative agent of necrotizing skin ulcerations in distinctive geographical areas. M. ulcerans produces a macrolide toxin, mycolactone, which has been identified as an important virulence factor in ulcer formation. Mycolactone is cytotoxic to fibroblasts and adipocytes in vitro and has modulating activity on immune cell functions. The effect of mycolactone on keratinocytes has not been reported previously and the mechanism of mycolactone toxicity is presently unknown. Many other macrolide substances have cytotoxic and immunosuppressive activities and mediate some of their effects via production of reactive oxygen species (ROS. We have studied the effect of mycolactone in vitro on human keratinocytes--key cells in wound healing--and tested the hypothesis that the cytotoxic effect of mycolactone is mediated by ROS. METHODOLOGY/PRINCIPAL FINDINGS: The effect of mycolactone on primary skin keratinocyte growth and cell numbers was investigated in serum free growth medium in the presence of different antioxidants. A concentration and time dependent reduction in keratinocyte cell numbers was observed after exposure to mycolactone. Several different antioxidants inhibited this effect partly. The ROS inhibiting substance deferoxamine, which acts via chelation of Fe(2+, completely prevented mycolactone mediated cytotoxicity. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that mycolactone mediated cytotoxicity can be inhibited by deferoxamine, suggesting a role of iron and ROS in mycolactone induced cytotoxicity of keratinocytes. The data provide a basis for the understanding of Buruli ulcer pathology and the development of improved therapies for this disease.

  10. African eggplant (Solanum anguivi Lam.) fruit with bioactive polyphenolic compounds exerts in vitro antioxidant properties and inhibits Ca2+-induced mitochondrial swelling

    Institute of Scientific and Technical Information of China (English)

    Olusola Olalekan Elekofehinti; Jean Paul Kamdem; Aline Augusti Bolingon; Margareth Linde Athayde; Seeger Rodrigo Lopes; Emily Pansera Waczuk; Ige Joseph Kade; Isaac Gbadura Adanlawo; Joao Batista Teixeira Rocha

    2013-01-01

    Objective: To evaluate the antioxidant and radical scavenging activities of Solanum anguivi fruit (SAG) and its possible effect on mitochondrial permeability transition pore as well as mitochondrial membrane potential (ΔΨm) isolated from rat liver. Methods: Antioxidant activity of SAG was assayed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, iron chelation and ability to inhibit lipid peroxidation in both liver and brain homogenate of rats. Also, the effect of SAG on mitochondrial membrane potential and mitochondrial swelling were determined. Identification and quantification of bioactive polyphenolics was done by HPLC-DAD. Results: SAG exhibited potent and concentration dependent free radical-scavenging activity (IC50/DPPH=275.03±7.8 µg/mL). Reductive and iron chelation abilities also increase with increase in SAG concentration. SAG also inhibited peroxidation of cerebral and hepatic lipids subjected to iron oxidative assault. SAG protected against Ca2+ (110 µmol/L)-induced mitochondrial swelling and maintained theΔΨm. HPLC analysis revealed the presence of gallic acid [(17.54±0.04) mg/g], chlorogenic acid (21.90±0.02 mg/g), caffeic acid (16.64±0.01 mg/g), rutin [(14.71±0.03) mg/g] and quercetin [(7.39±0.05) mg/g]. Conclusions:These effects could be attributed to the bioactive polyphenolic compounds present in the extract. Our results suggest that SAG extract is a potential source of natural antioxidants that may be used not only in pharmaceutical and food industry but also in the treatment of diseases associated with oxidative stress.

  11. Searching for new aluminium chelating agents: a family of hydroxypyrone ligands.

    Science.gov (United States)

    Toso, Leonardo; Crisponi, Guido; Nurchi, Valeria M; Crespo-Alonso, Miriam; Lachowicz, Joanna I; Mansoori, Delara; Arca, Massimiliano; Santos, M Amélia; Marques, Sérgio M; Gano, Lurdes; Niclós-Gutíerrez, Juan; González-Pérez, Josefa M; Domínguez-Martín, Alicia; Choquesillo-Lazarte, Duane; Szewczuk, Zbigniew

    2014-01-01

    Attention is devoted to the role of chelating agents in the treatment of aluminium related diseases. In fact, in spite of the efforts that have drastically reduced the occurrence of aluminium dialysis diseases, they so far constitute a cause of great medical concern. The use of chelating agents for iron and aluminium in different clinical applications has found increasing attention in the last thirty years. With the aim of designing new chelators, we synthesized a series of kojic acid derivatives containing two kojic units joined by different linkers. A huge advantage of these molecules is that they are cheap and easy to produce. Previous works on complex formation equilibria of a first group of these ligands with iron and aluminium highlighted extremely good pMe values and gave evidence of the ability to scavenge iron from inside cells. On these bases a second set of bis-kojic ligands, whose linkers between the kojic chelating moieties are differentiated both in terms of type and size, has been designed, synthesized and characterized. The aluminium(III) complex formation equilibria studied by potentiometry, electrospray ionization mass spectroscopy (ESI-MS), quantum-mechanical calculations and (1)H NMR spectroscopy are here described and discussed, and the structural characterization of one of these new ligands is presented. The in vivo studies show that these new bis-kojic derivatives induce faster clearance from main organs as compared with the monomeric analog.

  12. Production of chelating agents by Pseudomonas aeruginosa grown in the presence of thorium and uranium

    International Nuclear Information System (INIS)

    Chelating agents produced by microorganisms enhance the dissolution of iron increasing the mobility and bioavailability of the metal. Since some similarities exist in the biological behavior of ferric, thorium and uranyl ions, microorganisms resistant to these metals and which grow in their presence may produce sequestering agents of Th and U, and other metals in a manner similar to the complexation of iron by siderophores. The ability of P. aeruginosa to elaborate sequestering agents in medium containing thorium or uranium salts was tested. Uranium has a stronger inhibitory effect on growth of the organism than thorium at similar concentrations. Analyses of the culture media have shown, that relative to the control, and under the experimental conditions used, the microorganisms have produced several new chelating agents for thorium and uranium. Extracts containing these chelating agents have been tested for their decorporation potential. In vitro mouse liver bioassay and in vivo mouse toxicity tests indicate that their efficiency is comparable to DTPA and DFOA and that they are virtually non-toxic to mice. The bacterially produced compounds resemble, but are not identical to the known iron chelating siderophores isolated from microorganisms. Some of their chemical properties are also discussed. (author)

  13. Functional characterization of the chloroplast ferric chelate oxidoreductase enzyme.

    Science.gov (United States)

    Solti, Adám; Müller, Brigitta; Czech, Viktória; Sárvári, Éva; Fodor, Ferenc

    2014-05-01

    Iron (Fe) has an essential role in the biosynthesis of chlorophylls and redox cofactors, and thus chloroplast iron uptake is a process of special importance. The chloroplast ferric chelate oxidoreductase (cFRO) has a crucial role in this process but it is poorly characterized. To study the localization and mechanism of action of cFRO, sugar beet (Beta vulgaris cv Orbis) chloroplast envelope fractions were isolated by gradient ultracentrifugation, and their purity was tested by western blotting against different marker proteins. The ferric chelate reductase (FCR) activity of envelope fractions was studied in the presence of NAD(P)H (reductants) and FAD coenzymes. Reduction of Fe(III)-ethylenediaminetetraacetic acid was monitored spectrophotometrically by the Fe(II)-bathophenanthroline disulfonate complex formation. FCR activity, that is production of free Fe(II) for Fe uptake, showed biphasic saturation kinetics, and was clearly associated only to chloroplast inner envelope (cIE) vesicles. The reaction rate was > 2.5 times higher with NADPH than with NADH, which indicates the natural coenzyme preference of cFRO activity and its dependence on photosynthesis. FCR activity of cIE vesicles isolated from Fe-deficient plants also showed clear biphasic kinetics, where the KM of the low affinity component was elevated, and thus this component was down-regulated.

  14. High-throughput assay comparison and standardization for metal chelating capacity screening: A proposal and application.

    Science.gov (United States)

    Santos, Jânio Sousa; Alvarenga Brizola, Vitor Rafael; Granato, Daniel

    2017-01-01

    Aiming to standardize the experimental protocols to assess the ability to chelate Fe(2+) and Cu(2+) using 96-well microplates, we analyzed Brazilian coffees (n=20) as a study-case in relation to their antioxidant activity using conventional methods (DPPH and FRAP assays) and correlated the results with the total phenolic content (TPC) using bivariate and multivariate statistical approaches. Complementarily, we assessed the repeatability, reproducibility, recovery, and linearity of both methods. Data showed that the proposed assays presented a good repeatability and reproducibility (assays, respectively. Both methods were linear in the range of 0-100mg EDTA equivalents/L. Cu(2+)-chelating ability was significantly correlated to FRAP, DPPH, and TPC, while sparse (passays can be used to assess the ability of plant-based extracts to chelate Fe(2+) and Cu(2+)in vitro. PMID:27507505

  15. COMPARATIVE EVALUATION OF ANTIOXIDANT AND ANTIHEMOLYTIC CAPACITIES OF PLANTS OF INDIAN ORIGIN USING MULTIPLE ANTIOXIDANT ASSAYS

    OpenAIRE

    Deepinderjeet Singh Joshan; Shruti Rawal

    2012-01-01

    The present study is concerned with both in-vitro assessment of antioxidant activity and anti-hemolytic effects of Ficus bengalensis, Calendula officinalis and Juglans regia. Total flavonoids and phenolics also were determined by using aluminum nitrate and Folin–Ciocalteu colorimetric methods respectively. The antioxidant capacity of sample was assessed through reducing power assay, DPPH-scavenging effect,metal chelation assay and superoxide scavenging assay. The extract of Calendula officina...

  16. In vitro antioxidant activities of sulfated polysaccharide ascophyllan isolated from Ascophyllum nodosum.

    Science.gov (United States)

    Abu, Ryogo; Jiang, Zedong; Ueno, Mikinori; Okimura, Takasi; Yamaguchi, Kenichi; Oda, Tatsuya

    2013-08-01

    Antioxidant activities of sulfated polysaccharide ascophyllan from Ascophyllum nodosum was investigated in vitro by various assays, and compared with those of fucoidan. A chemiluminescence (CL) analysis using a luminol analog, L-012, showed that ascophyllan scavenges superoxide, and the activity is greater than fucoidan. However, in the presence of 10μg/ml of ascophyllan or 10μg/ml and 100μg/ml of fucoidan, slightly enhanced CL-responses were observed. Since EDTA-treatment resulted in disappearance of the enhancement effects, it was suggested that metal ions especially iron ions in the polysaccharides might be involved in this phenomenon. In fact, metal element analysis revealed that ascophyllan and fucoidan inherently contain iron and other metal elements. EDTA-treatment resulted in significant increase in Fe(2+)-chelating activities of these polysaccharides. In an electron spin resonance (ESR)-spin trapping analysis in which direct UV-radiation to hydrogen peroxide was used as a source of hydroxyl radical, ascophyllan and fucoidan showed potent hydroxyl radical scavenging activity with similar extent. Reducing power of ascophyllan was stronger than that of fucoidan. Our results indicate that ascophyllan can exhibit direct and potent antioxidant activity. PMID:23643974

  17. Efficient solvent extraction of antioxidant-rich extract from a tropical diatom,Chaetoceros calcitrans (Paulsen) Takano 1968

    Institute of Scientific and Technical Information of China (English)

    Su Chern Foo; Fatimah Md Yusoff; Maznah Ismail; Mahiran Basri; Nicholas Mun Hoe Khong; Kim Wei Chan; Sook Kun Yau

    2015-01-01

    Objective:To compare thein vitro antioxidant capacity of a diatom,Chaetoceros calcitrans (C. calcitrans) extracted using six types of solvents. Methods:Each extract was evaluated in terms of extraction yield, total carotenoid, fucoxanthin content, total phenolic and antioxidant capacities (DPPH• andABTS•+ scavenging activity and iron chelating activity). Results: The methanol extract exhibited the highest yield [(22.71 ± 0.96) g/100 g dry weight (DW)], total carotenoid [(4.46 ± 0.36) mg/g DW], total phenolic [(2.49 ± 0.08) mg gallic acid equivalents/g DW] and second highest fucoxanthin content [(2.08 ± 0.03) mg fucoxanthin/g DW] as compared to other solvent extracts. Methanolic extract also exhibited significantly higher (P Conclusions: Methanol was the recommended solvent for the production of antioxidant rich extract fromC. calcitrans. Both carotenoids and phenolic acids were found to be positively correlated to the antioxidant capacities ofC. calcitrans. Lead bioactives confirmed by subsequent high performance liquid chromatography studies were fucoxanthin, gallic acid and protocatechuic acid.

  18. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains......, where it serves as a storage molecule for phosphorous. Phytic acid is also associated with minerals. The minerals are bound by chelation to the negatively charged phosphate groups in phytic acid. Phytases catalyse the dephosphorylation of phytic acid, thus releasing bound minerals to make them available...

  19. Baicalin interferes with iron accumulation in C6 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Chunyan Guo; Xin Chen

    2011-01-01

    Baicalin reacts with ferric ammonium citrate and acts as an-iron chelator. The maximal reaction time for baicalin to interact with irons was approximately 3 hours. C6 glioma cell survival decreased following iron-loading, with a large number of cells accumulating iron. In addition, lipid peroxidation increased. Iron accumulation and lipid peroxidation were the major cause of cellular death. Baicalin and ferric ammonium citrate alleviated iron accumulation in C6 cells and lowered the mortality of nerve cells. In addition, malondialdehyde and lactate dehydrogenase levels reduced. These results indicate that baicalin strongly inhibits lipid peroxidation via chelation, reduces the content of iron in C6 cells, lowers lipid peroxidation, and thus plays a protective role against iron-induced nerve cell death.

  20. Antioxidant, antihemolytic and nephroprotective activity of aqueous extract of Diospyros lotus seeds.

    Science.gov (United States)

    Moghaddam, Akbar Hajizadeh; Nabavi, Seyed Mohammad; Nabavi, Seyed Fazel; Bigdellou, Rata; Mohammadzadeh, Sakineh; Ebrahimzadeh, Mohammad Ali

    2012-01-01

    This study was conducted to quantitatively evaluate the antioxidant, antihemolytic and nephroprotective effects of Diospyros lotus seeds extract in experimental in vitro and in vivo models. Antioxidant potential of Diospvyos lotus seeds extract was examined by employing seven in vito models i.e., DPPH, nitric oxide and hydrogen peroxide radicals scavenging activity, iron ion chelating, reducing power and lipid peroxidation through linoleic acid. Antihemolytic activity of extract was examined against hydrogen peroxide-induced erythrocytes hemolysis. Also, nephroprotective effect of extract against gentamicin (GM)-induced renal injury was evaluated. Renal injury was achieved by injecting 100 mg/kg, intraperitoneally (i.p.) of GM in normal saline. Extracts were administrated i.p. in doses 200 and 400 mg/kg. Blood samples were examined for serum creatinine and blood urea nitrogen after 10 consecutive days of treatment. Results show that extract showed different level of antioxidant and antihemolytic activity in the studied models. Also, results show that GM-induced nephrotoxic animal model was successfully constructed. Extract attenuated the gentamicin-induced increase in level of serum creatinine and blood urea nitrogen. The present study shows that the extract offered significant biological action compared with standard compound.

  1. Antioxidant and anticholinesterase effects of frequently consumed cereal grains using in vitro test models.

    Science.gov (United States)

    Senol, F Sezer; Kan, Asuman; Coksari, Gulay; Orhan, Ilkay Erdogan

    2012-08-01

    The ethyl acetate and ethanol extracts obtained from eight varieties (Faikbey, Y-1779, CI-8357, Cheokota, Seydişehir, Y-330, Sivas and YVD-18) of oat (Avena sativa L.), one variety (Larende) of barley (Hordeum vulgare L.), one variety (Tatlicak 97) of triticale (Triticale sp.) and one rye variety (Aslim 95) (Secale cereale L.) were investigated for their antioxidant effects in seven test systems. Anticholinesterase activity of the extracts was examined by enzyme-linked immunosorbent assay (ELISA) microplate reader. Total phenol and flavonoid contents were calculated using Folin Ciocalteau and AlCl₃ reagents, respectively. All of the extracts were ineffective in cholinesterase inhibition assays and had weak-to-moderate activity in antioxidant assays. The extracts exerted better activity in iron-chelation capacity ranging between 43.17 ± 2.04 and 62.97 ± 1.29%. Triticale extracts showed higher activity in reducing power experiments. A notable difference in the results of the antioxidant activity assays was observed among the oat varieties.

  2. Metal ions, Alzheimer's disease and chelation therapy.

    Science.gov (United States)

    Budimir, Ana

    2011-03-01

    In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases.

  3. Metal ions, Alzheimer's disease and chelation therapy.

    Science.gov (United States)

    Budimir, Ana

    2011-03-01

    In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases. PMID:21406339

  4. Antioxidant activity of methanolic leaf extract of Moringa peregrina (Forssk.) Fiori.

    OpenAIRE

    Dehshahri, S.; Wink, M.; Afsharypuor, S.; Asghari, G.; Mohagheghzadeh, A.

    2012-01-01

    Natural antioxidants have an important role in the prevention of many age-related diseases and promotion of health. Among natural antioxidants from plants, flavonoids and other phenolic compounds are potent antioxidants and chelating agents. Moringa peregrina (Forssk.) Fiori (Moringaceae) is a small desert tree distributed from tropical Africa to east India. Moringa tree is also growing in south-east of Iran. The antioxidant activity of M. peregrina methanolic leaf extract on 2,2-diphenyl-1-p...

  5. Critical evaluation of treatment strategies involving adsorption and chelation for wastewater containing copper, zinc and cyanide

    Energy Technology Data Exchange (ETDEWEB)

    Bose, P.; Bose, M.A.; Kumar, S. [Indian Inst. of Technology, Kanpur (India). Dept Civil Engineering, Environmental Engineering & Management Programme

    2002-11-01

    Industrial wastewater containing heavy metals and cyanide must be treatment for removal of both metals and cyanide before disposal. The study described evaluated treatment strategies involving some indigenous adsorbents and a low-cost chelating agent for treatment of a simulated wastewater containing copper and zinc, complexed with cyanide. Treatment strategies involving three adsorbents, sulfonated coal, biosorbent G. lucidum, and iron oxide coated sand (IOCS), and a chelating agent, insoluble agro-based starch xanthate (IAX), were tested. The evaluation procedure involved comparison of the performance of these treatment strategies with that of conventional treatment. Results indicate that treatment using the chelating agent IAX has the greatest potential as an alternative to the conventional treatment technique. The three adsorbents tested, although reported to be very effective in removing copper and zinc from pure systems, exhibit diminished metal removal capacity in the presence of cyanide, and hence are unsuitable.

  6. Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture

    OpenAIRE

    Radzki, W.; Gutierrez Mañero, F. J.; Algar, E.; Lucas García, J. A.; García-Villaraco, A.; Ramos Solano, B.

    2013-01-01

    Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved toma...

  7. Liver iron content determination by magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Konstantinos; Tziomalos; Vassilios; Perifanis

    2010-01-01

    Accurate evaluation of iron overload is necessary to establish the diagnosis of hemochromatosis and guide chelation treatment in transfusion-dependent anemia. The liver is the primary site for iron storage in patients with hemochromatosis or transfusion-dependent anemia, therefore, liver iron concentration (LIC) accurately re? ects total body iron stores. In the past 20 years, magnetic resonance imaging (MRI) has emerged as a promising method for measuring LIC in a variety of diseases. We review the potenti...

  8. Transferrin as a source of iron for Campylobacter rectus

    OpenAIRE

    Grenier, Daniel; Tanabe, Shin-Ichi

    2011-01-01

    Background and Objective: Campylobacter rectus is considered as one of the bacterial species of etiological importance in periodontitis. Iron-containing proteins such as transferrin are found in periodontal sites and may serve as a source of iron for periodontopathogens. The aim of this study was to investigate the capacity of C. rectus to assimilate transferrin-bound iron to support its growth. Design: Growth studies were performed in broth media pretreated with an iron-chelating resin and s...

  9. Antioxidant activity of ethanolic extract from cultivated strawberries’ leaves (Fragariae folium

    Directory of Open Access Journals (Sweden)

    Stanojević Ljiljana P.

    2015-01-01

    Full Text Available Strawberry is a member of the rose family (Rosaceae, subfamily Rosoideae, tribe Potentilleae in the genus Fragaria. The cultivated varieties of commercial strawberries usually were designated as Fragaria ananassa. Root, leaf, flower and fruit have the healing properties. The strawberry leaves extract is used for blood cleaning, for treatment of oral inflammation, diarrhea, various gastro-intestinal inflammation, and hemorrhoids, as well as a diuretic. So far, many positive biological effects of strawberries (anticancer, antioxidant and anticoagulant effect have been proven. The purpose of this study was to evaluate the antioxidant potential of ethanolic extract from cultivated strawberries (Fragariae folium, varieties Senga Sengana by using different antioxidant assays (DPPH, FRAP, FIC, H2O2 and TBA-MDA. Ethanolic extract from strawberry leaves was obtained by reflux extraction at the boiling temperature. Total phenols and total flavonoids content was determined spectrophotometrically by the method of Folin-Ciocalteu and by method with AlCl3, respectively. In the extract was determined high content of total phenols, while the total flavonoid content is much lower. The concentrations of extract required to neutralize 50% of the initial concentration of DPPH radicals (EC50 after 20 minutes incubation and immediately after adding DPPH radical solution were 7,91 and 19,46 μgcm-3, respectively. Extract was achieved the maximum iron ions chelating ability (67.89% at a concentration of 2 mgcm-3. Inhibition of lipid peroxidation of 70% was achieved by extract concentration of 0.03125 mgcm-3, while the maximum neutralization of H2O2 (30.47% was achieved by extract concentration of 0.5 mgcm-3. FRAP value of the investigated extract is 284.51 mgFe/g of dry extract. Presented results of the antioxidant activity show that the obtained extract from the cultivated strawberry leaves is a potential source of natural antioxidants. [Projekat Ministarstva nauke

  10. Structural, Chemical and Biological Aspects of Antioxidants for Strategies Against Metal and Metalloid Exposure

    Directory of Open Access Journals (Sweden)

    Swaran J. S. Flora

    2009-01-01

    Full Text Available Oxidative stress contributes to the pathophysiology of exposure to heavy metals/metalloid. Beneficial renal effects of some medications, such as chelation therapy depend at least partially on the ability to alleviate oxidative stress. The administration of various natural or synthetic antioxidants has been shown to be of benefit in the prevention and attenuation of metal induced biochemical alterations. These include vitamins, N-acetylcysteine, α-lipoic acid, melatonin, dietary flavonoids and many others. Human studies are limited in this regard. Under certain conditions, surprisingly, the antioxidant supplements may exhibit pro-oxidant properties and even worsen metal induced toxic damage. To date, the evidence is insufficient to recommend antioxidant supplements in subject with exposure to metals. Prospective, controlled clinical trials on safety and effectiveness of different therapeutic antioxidant strategies either individually or in combination with chelating agent are indispensable. The present review focuses on structural, chemical and biological aspects of antioxidants particularly related to their chelating properties.

  11. Chelating agents in pharmacology, toxicology and therapeutics

    International Nuclear Information System (INIS)

    The proceedings contain 71 abstracts of papers. Fourteen abstracts were inputted in INIS. The topics covered include: the effects of chelating agents on the retention of 63Ni, 109Cd, 203Hg, 144Ce, 95Nb and the excretion of 210Po, 63Ni, 48V, 239Pu, 241Am, 54Mn; the applications of tracer techniques for studies of the efficacy of chelation therapy in patients with heart and brain disorders; and the treatment of metal poisoning with chelating agents. (J.P.)

  12. Use of countercurrent chromatography during isolation of 6-hydroxyluteolin-7-O-β-glucoside, a major antioxidant of Athrixia phylicoides.

    Science.gov (United States)

    de Beer, Dalene; Joubert, Elizabeth; Malherbe, Christiaan J; Jacobus Brand, D

    2011-09-01

    Athrixia phylicoides, an indigenous South African herbal tea, has potential as a source of nutraceutical antioxidant extracts. Countercurrent chromatography (CCC) was employed as part of a multi-step process to isolate one of the major antioxidant compounds in A. phylicoides extracts. Antioxidant activity of the extracts was comparable to commercial nutraceutical extracts from Aspalathus linearis and Cyclopia spp. in a range of assays. The extracts were tested for radical scavenging (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) di-ammonium radical cation (ABTS·⁺) scavenging, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging and oxygen radical absorbance capacity (ORAC)), ferric reducing antioxidant potential (FRAP) and iron chelating activity, as well as inhibition of microsomal lipid and linoleic acid emulsion oxidation. After extraction optimisation, the antioxidant activity of the major phenolic compounds in an A. phylicoides extract was determined using the on-line HPLC-diode-array-DPPH and -ABTS·⁺ radical scavenging assays. Major compounds reported for the first time included chlorogenic acid, 1,3-dicaffeoylquinic acid, several hydroxycinnamic acid derivatives, including dicaffeoyl quinic acids, and an unidentified flavone-hexose. Finally, CCC was used in conjunction with liquid-liquid partitioning and semi-preparative reversed-phase HPLC to isolate 6-hydroxyluteolin-7-O-β-glucoside (a major antioxidant) and quercetagetin-7-O-β-glucoside (a minor compound present in CCC fraction containing 6-hydroxyluteolin-7-O-β-glucoside) from an A. phylicoides extract. The chemical structures of the isolated compounds were confirmed by LC high-resolution electrospray ionisation MS, as well as ¹H, ¹³C and 2D NMR spectroscopy. This is the first report of the isolation of these compounds from A. phylicoides. PMID:21236437

  13. COMPARATIVE EVALUATION OF ANTIOXIDANT AND ANTIHEMOLYTIC CAPACITIES OF PLANTS OF INDIAN ORIGIN USING MULTIPLE ANTIOXIDANT ASSAYS

    Directory of Open Access Journals (Sweden)

    Deepinderjeet Singh Joshan

    2012-09-01

    Full Text Available The present study is concerned with both in-vitro assessment of antioxidant activity and anti-hemolytic effects of Ficus bengalensis, Calendula officinalis and Juglans regia. Total flavonoids and phenolics also were determined by using aluminum nitrate and Folin–Ciocalteu colorimetric methods respectively. The antioxidant capacity of sample was assessed through reducing power assay, DPPH-scavenging effect,metal chelation assay and superoxide scavenging assay. The extract of Calendula officinalis was found to be more efficient in as antioxidant and anti-hemolytic agents using the in vitro assays as compared to Ficus bengalensis and Juglans regia.

  14. Responses to Iron-Deficiency in Arabidopsis-Thaliana - The Turbo Iron Reductase does not depend on the Formation of Root Hairs and Transfer Cells.

    NARCIS (Netherlands)

    Moog, P.R.; Van der Kooij, T.A.W.; Bruggemann, W.; Schiefelbein, J.W.; Kuiper, P.J.C.

    1995-01-01

    Arabidopsis thaliana (L.) Heynh. Columbia wild type and a root hair-less mutant RM57 were grown on iron-containing and iron-deficient nutrient solutions. In both genotypes, ferric chelate reductase (FCR) of intact roots was induced upon iron deficiency and followed a Michaelis-Menten kinetic with a

  15. Antioxidant activities of Sarcodon imbricatum wildly grown in the black sea region of Turkey

    Directory of Open Access Journals (Sweden)

    Tevfik Ozen

    2010-01-01

    Full Text Available The antioxidant activities of the methanol extract of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey were investigated in this study. Antioxidant activities were evaluated in terms of total antioxidant activity, reducing power, metal chelating ability, inhibition of linoleic acid peroxidation, superoxide, peroxide and hydrogen peroxide scavenging effects. Various antioxidant activities were compared to references antioxidants such as α-tocopherol, butylated hydroxyanisole (BHA, butylated hydroxytoluene (BHT, and trolox. In total antioxidant (12674.45 ΅mol α-tocopherol/g of extract, superoxide scavenging (53.74% and peroxide scavenging activity (45.73%, the methanol extract of Sarcodon imbricatum showed stronger activity patterns than that of references antioxidants. Reducing power, metal chelating activity and free radical (DPPH· scavenging activity was increased with the increasing concentration. The contents of total phenolic, flavonoid, anthocyanin, ascorbic acid, β-carotene and lycopene of Sarcodon imbricatum were determined and found to be noteworthy.

  16. SYNTHESIS AND APPLICATION OF IMINOCARBOXYLIC CHELATING FIBERS

    Institute of Scientific and Technical Information of China (English)

    LiHangqiu; ZhouShaoji

    1997-01-01

    In this paper,fibrous chelating exchangers with-N(CH2COOH)2 group have been prepared for the first time by a weakly basic anion exchange fiber (aminated fiber)as the starting materials.The fibers were quite effective for the adsorption of heavy metal ion such as Cu2+.In addition,IR spectrum of the structure of fibers confirms that it is feasible to prepare iminocarboxylic chelating fiber through direct carboxylation reaction.

  17. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    Science.gov (United States)

    Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

    1998-01-01

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

  18. Curcumin interaction with copper and iron suggests one possible mechanism of action in Alzheimer's disease animal models.

    Science.gov (United States)

    Baum, Larry; Ng, Alex

    2004-08-01

    Curcumin is a polyphenolic diketone from turmeric. Because of its anti-oxidant and anti-inflammatory effects, it was tested in animal models of Alzheimer's disease, reducing levels of amyloid and oxidized proteins and preventing cognitive deficits. An alternative mechanism of these effects is metal chelation, which may reduce amyloid aggregation or oxidative neurotoxicity. Metals can induce Abeta aggregation and toxicity, and are concentrated in AD brain. Chelators desferrioxamine and clioquinol have exhibited anti-AD effects. Using spectrophotometry, we quantified curcumin affinity for copper, zinc, and iron ions. Zn2+ showed little binding, but each Cu2+ or Fe2+ ion appeared to bind at least two curcumin molecules. The interaction of curcumin with copper reached half-maximum at approximately 3-12 microM copper and exhibited positive cooperativity, with Kd1 approximately 10-60 microM and Kd2 approximately 1.3 microM (for binding of the first and second curcumin molecules, respectively). Curcumin-iron interaction reached half-maximum at approximately 2.5-5 microM iron and exhibited negative cooperativity, with Kd1 approximately 0.5-1.6 microM and Kd2 approximately 50-100 microM. Curcumin and its metabolites can attain these levels in vivo, suggesting physiological relevance. Since curcumin more readily binds the redox-active metals iron and copper than redox-inactive zinc, curcumin might exert a net protective effect against Abeta toxicity or might suppress inflammatory damage by preventing metal induction of NF-kappaB.

  19. Lipophilic aroylhydrazone chelator HNTMB and its multiple effects on ovarian cancer cells

    Directory of Open Access Journals (Sweden)

    Singh Rakesh K

    2010-02-01

    Full Text Available Abstract Background Metal chelators have gained much attention as potential anti-cancer agents. However, the effects of chelators are often linked solely to their capacity to bind iron while the potential complexation of other trace metals has not been fully investigated. In present study, we evaluated the effects of various lipophilic aroylhydrazone chelators (AHC, including novel compound HNTMB, on various ovarian cancer cell lines (SKOV-3, OVCAR-3, NUTU-19. Methods Cell viability was analyzed via MTS cytotoxicity assays and NCI60 cancer cell growth screens. Apoptotic events were monitored via Western Blot analysis, fluorescence microscopy and TUNEL assay. FACS analysis was carried out to study Cell Cycle regulation and detection of intracellular Reactive Oxygen Species (ROS Results HNTMB displayed high cytotoxicity (IC50 200-400 nM compared to previously developed AHC (oVtBBH, HNtBBH, StBBH/206, HNTh2H/315, HNI/311; IC50 0.8-6 μM or cancer drug Deferoxamine, a hexadentate iron-chelator (IC50 12-25 μM. In a NCI60 cancer cell line screen HNTMB exhibited growth inhibitory effects with remarkable differences in specificity depending on the cell line studied (GI50 10 nM-2.4 μM. In SKOV-3 ovarian cancer cells HNTMB treatment led to chromatin fragmentation and activation of the extrinsic and intrinsic pathways of apoptosis with specific down-regulation of Bcl-2. HNTMB caused delayed cell cycle progression of SKOV-3 through G2/M phase arrest. HNTMB can chelate iron and copper of different oxidation states. Complexation with copper lead to high cytotoxicity via generation of reactive oxygen species (ROS while treatment with iron complexes of the drug caused neither cytotoxicity nor increased ROS levels. Conclusions The present report suggests that both, non-complexed HNTMB as a chelator of intracellular trace-metals as well as a cytotoxic HNTMB/copper complex may be developed as potential therapeutic drugs in the treatment of ovarian and other

  20. Antioxidant activities of protein hydrolysates obtained from the housefly larvae.

    Science.gov (United States)

    Zhang, Huan; Wang, Pan; Zhang, Ai-Jun; Li, Xuan; Zhang, Ji-Hong; Qin, Qi-Lian; Wu, Yi-Jun

    2016-09-01

    The housefly is an important resource insect and the housefly larvae are ideal source of food additives. The housefly larvae protein hydrolysates were obtained by enzymatic hydrolysis by alcalase and neutral proteinase. Their antioxidant activities were investigated, including the superoxide and hydroxyl radicalscavenging activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, reducing power and metal chelating activity. The antioxidant activities of both hydrolysates increased with their increasing concentrations. The alcalase hydrolysate (AH) showed higher scavenging activities against hydroxyl radical and superoxide anion radical at low concentrations and higher metal-chelating activity than the neutral proteinase hydrolysate (NPH). The NPH exhibited higher scavenging activity against DPPH free radical and higher reducing power than the AH. Both hydrolysates showed more than 50% superoxide anion radical-scavenging activity at 10 μg/mL. These results indicate that both housefly larvae protein hydrolysates display high antioxidant activities and they could serve as potential natural antioxidant food additives. PMID:27630047

  1. Optimization of Preparation Process for Cod Skin Collagen Peptide-Iron (Ⅱ) Chelate via Response Surface Methodology%响应面法优化鳕鱼皮胶原蛋白肽螯合铁工艺

    Institute of Scientific and Technical Information of China (English)

    蔡冰娜; 陈忻; 潘剑宇; 邓婉桦; 万鹏; 陈得科; 孙恢礼

    2012-01-01

    The optimal chelating conditions for cod skin collagen peptide and ferrous chloride were investigated by response surface methodology(RSM) to explore the effects of pH(X1),collagen peptide-ferrous chloride ratio(X2) and collagen peptide concentration(X3) on chelating efficiency.The optimal chelating conditions were collagen peptide-ferrous chloride ratio of 4:1,collagen peptide concentration of 3.5% and pH 7.0.Under the optimal chelating conditions,the predicted and experimental yields of the peptide-iron(Ⅱ) chelate were 37.46% and 37.31%,respectively.The infrared spectral analysis revealed that the ferrous ions were chelated with NH2+and COO-groups,suggesting the formation of a new kind of peptide-iron(Ⅱ) chelate.%采用响应面法优化鳕鱼皮胶原蛋白肽与氯化亚铁进行螯合反应的条件,制备小分子肽螯合铁产品。以pH值、小分子肽与FeCl2的质量比和小分子肽液质量分数3因素的5水平进行二次正交旋转组合试验,建立螯合物得率的二次回归方程。结果表明:最佳螯合工艺条件为胶原蛋白肽与氯化亚铁的质量比4:1、小分子肽液质量分数3.5%、pH7.0。在此条件下,螯合物得率为37.31%,与模型的预测值37.46%接近。红外光谱检测结果显示,亚铁离子与小分子肽中的NH2+和COO-有螯合,是一种新型螯合物。

  2. Antioxidant activity of wheat and buckwheat flours

    Directory of Open Access Journals (Sweden)

    Sedej Ivana J.

    2010-01-01

    Full Text Available Antioxidative activities of wheat flours (type 500 and wholegrain and buckwheat flours (light and wholegrain were tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH·-scavenging activity, reducing power and chelating activity on Fe2+. Also, the content of the total phenolics of ethanolic extracts was estimated. Polyphenolics content (expressed as gallic acid equivalent, GAE in wheat flours varied between 37.1 and 137.2 μg GAE/g extract, while its content in buckwheat flour were at least four time higher and ranged between 476.3 and 618.9μg GAE/g extract. Ethanolic extracts of buckwheat flours exhibited higher antioxidant activities in all the assays, except for chelating activity. Regarding all the obtained results, it can be concluded that bakery products produced with buckwheat flour could be regarded as potential functional foods.

  3. PDTC, metal chelating compound, induces G1 phase cell cycle arrest in vascular smooth muscle cells through inducing p21Cip1 expression: involvement of p38 mitogen activated protein kinase.

    Science.gov (United States)

    Moon, Sung-Kwon; Jung, Sun-Young; Choi, Yung-Hyun; Lee, Young-Choon; Patterson, Cam; Kim, Cheorl-Ho

    2004-02-01

    Pyrrolidine dithiocarbamate (PDTC), a metal chelating compound, is known to induce cell death in vascular smooth muscle cells (VSMC). However, the molecular mechanism for PDTC-induced VSMC death is not well understood. Addition of PDTC reduced cell growth and DNA synthesis on VSMC in low density conditions. However, in serum depleted medium, PDTC did not affect the cell viability, suggesting that certain factors in serum may mediate the cytotoxic effect of PDTC. Several metal chelators prevented the cell death induced by PDTC. In a serum-deprived condition, addition of exogenous metals, copper, iron, and zinc, restored the cytotoxic effect of PDTC. These data indicate that metals such as copper, iron, and zinc in serum may mediate the cytotoxic effect of PDTC. At low VSMC density in 10% FBS, treatment of PDTC, which induced a cell-cycle block in G1-phase, induced down-regulation of cyclins and CDKs and up-regulation of the CDK inhibitor p21 expression, whereas up-regulation of p27 or p53 by PDTC was not observed. Finally, we determined PDTC-mediated signaling pathway involved in VSMC death. Among relevant pathways, PDTC induced marked activation of p38MAPK and JNK. Expression of dominant negative p38MAPK and SB203580, a p38MAPK specific inhibitor, blocked PDTC-dependent p38MAPK, growth inhibition, and p21 expression. These data demonstrate that the p38MAPK pathway participates in p21 induction, which consequently leads to decrease of cyclin D1/cdk4 and cyclin E/cdk2 complexes and PDTC-dependent VSMC growth inhibition. In conclusion, an understanding of the molecular mechanisms of PDTC in VSMC provides a theoretical basis for clinical approaches using antioxidant therapies in atherosclerosis. PMID:14603533

  4. The antioxidant role of xanthurenic acid in the Aedes aegypti midgut during digestion of a blood meal.

    Directory of Open Access Journals (Sweden)

    Vitor L A Lima

    Full Text Available In the midgut of the mosquito Aedes aegypti, a vector of dengue and yellow fever, an intense release of heme and iron takes place during the digestion of a blood meal. Here, we demonstrated via chromatography, light absorption and mass spectrometry that xanthurenic acid (XA, a product of the oxidative metabolism of tryptophan, is produced in the digestive apparatus after the ingestion of a blood meal and reaches milimolar levels after 24 h, the period of maximal digestive activity. XA formation does not occur in the White Eye (WE strain, which lacks kynurenine hydroxylase and accumulates kynurenic acid. The formation of XA can be diminished by feeding the insect with 3,4-dimethoxy-N-[4-(3-nitrophenylthiazol-2-yl] benzenesulfonamide (Ro-61-8048, an inhibitor of XA biosynthesis. Moreover, XA inhibits the phospholipid oxidation induced by heme or iron. A major fraction of this antioxidant activity is due to the capacity of XA to bind both heme and iron, which occurs at a slightly alkaline pH (7.5-8.0, a condition found in the insect midgut. The midgut epithelial cells of the WE mosquito has a marked increase in occurrence of cell death, which is reversed to levels similar to the wild type mosquitoes by feeding the insects with blood supplemented with XA, confirming the protective role of this molecule. Collectively, these results suggest a new role for XA as a heme and iron chelator that provides protection as an antioxidant and may help these animals adapt to a blood feeding habit.

  5. Antioxidant effect of bisphosphonates and simvastatin on chondrocyte lipid peroxidation

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the effect of bisphosphonates (BPs) and simvastatin on chondrocyte lipid peroxidation. For this purpose, a flow cytometrical method using C11-BODIPY581/591 was developed to detect hydroperoxide-induced lipid peroxidation in chondrocytes. Tertiary butylhydroperoxide (t-BHP) induced a time and concentration dependent increase in chondrocyte lipid peroxidation. Addition of a Fe2+/EDTA complex to t-BHP or hydrogen peroxide (H2O2) clearly enhanced lipid peroxidation. The lipophilic simvastatin demonstrated a small inhibition in the chondrocyte lipid peroxidation. None of three tested BPs (clodronate, pamidronate, and risedronate) had an effect on chondrocyte lipid peroxidation induced by t-BHP. However, when Fe2+/EDTA complex was added to t-BHP or H2O2, BPs inhibited the lipid peroxidation process varying from 25% to 58%. This study demonstrates that BPs have antioxidant properties as iron chelators, thereby inhibiting the chondrocyte lipid peroxidation. These findings add evidence to the therapeutic potential of bisphosphonates and statins in rheumatoid arthritis

  6. Chemistry and pharmacological properties of some natural and synthetic antioxidants for heavy metal toxicity.

    Science.gov (United States)

    Flora, S J S; Shrivastava, Rupal; Mittal, Megha

    2013-01-01

    Heavy metals are known to cause oxidative deterioration of bio-molecules by initiating free radical mediated chain reaction resulting in lipid per-oxidation, protein oxidation and oxidation of nucleic acid like DNA and RNA. The development of effective dual functioning antioxidants, possessing both metal-chelating and free radical-scavenging properties should bring into play. Administration of natural and synthetic antioxidants like, quercetin, catechin, taurine, captopril, gallic acid, melatonin, N-acetyl cysteine, α- lipoic acid and others have been recognized in the disease prevention and clinical recovery against heavy metal intoxication. These antioxidants affect biological systems not only through direct quenching of free radicals but also via chelation of toxic metal(s). These antioxidants also, have the capacity to enhance cellular antioxidant defense mechanism by regenerating endogenous antioxidants, such as glutathione and vitamin C and E. They also influence cellular signaling and trigger redox sensitive regulatory pathways. The reactivity of antioxidants in protecting against heavy metal induced oxidative stress depends upon their structural properties, their partitioning abilities between hydrophilic and lipophilic environment and their hydrogen donation antioxidant properties. Herein, we review the structural, biochemical and pharmacological properties of selected antioxidants with particular reference to their ability to (i) chelate heavy metals from its complex (ii) ameliorate free radical (iii) terminate heavy metal induced free radical chain reaction (iv) regenerate endogenous antioxidants and, (v) excretion of metal without its redistribution.

  7. Chemistry and pharmacological properties of some natural and synthetic antioxidants for heavy metal toxicity.

    Science.gov (United States)

    Flora, S J S; Shrivastava, Rupal; Mittal, Megha

    2013-01-01

    Heavy metals are known to cause oxidative deterioration of bio-molecules by initiating free radical mediated chain reaction resulting in lipid per-oxidation, protein oxidation and oxidation of nucleic acid like DNA and RNA. The development of effective dual functioning antioxidants, possessing both metal-chelating and free radical-scavenging properties should bring into play. Administration of natural and synthetic antioxidants like, quercetin, catechin, taurine, captopril, gallic acid, melatonin, N-acetyl cysteine, α- lipoic acid and others have been recognized in the disease prevention and clinical recovery against heavy metal intoxication. These antioxidants affect biological systems not only through direct quenching of free radicals but also via chelation of toxic metal(s). These antioxidants also, have the capacity to enhance cellular antioxidant defense mechanism by regenerating endogenous antioxidants, such as glutathione and vitamin C and E. They also influence cellular signaling and trigger redox sensitive regulatory pathways. The reactivity of antioxidants in protecting against heavy metal induced oxidative stress depends upon their structural properties, their partitioning abilities between hydrophilic and lipophilic environment and their hydrogen donation antioxidant properties. Herein, we review the structural, biochemical and pharmacological properties of selected antioxidants with particular reference to their ability to (i) chelate heavy metals from its complex (ii) ameliorate free radical (iii) terminate heavy metal induced free radical chain reaction (iv) regenerate endogenous antioxidants and, (v) excretion of metal without its redistribution. PMID:24206124

  8. Antioxidant activity of taxifolin: an activity-structure relationship.

    Science.gov (United States)

    Topal, Fevzi; Nar, Meryem; Gocer, Hulya; Kalin, Pınar; Kocyigit, Umit M; Gülçin, İlhami; Alwasel, Saleh H

    2016-08-01

    Taxifolin is a kind of flavanonol, whose biological ability. The objectives of this study were to investigate the antioxidants and antiradical activities of taxifolin by using different in vitro bioanalytical antioxidant methods including DMPD√(+), ABTS√(+), [Formula: see text], and DPPH√-scavenging effects, the total antioxidant influence, reducing capabilities, and Fe(2+)-chelating activities. Taxifolin demonstrated 81.02% inhibition of linoleic acid emulsion peroxidation at 30 µg/mL concentration. At the same concentration, standard antioxidants including trolox, α-tocopherol, BHT, and BHA exhibited inhibitions of linoleic acid emulsion as 88.57, 73.88, 94.29, and 90.12%, respectively. Also, taxifolin exhibited effective DMPD√(+), ABTS√(+), [Formula: see text], and DPPH√-scavenging effects, reducing capabilities, and Fe(2+)-chelating effects. The results obtained from this study clearly showed that taxifolin had marked antioxidant, reducing ability, radical scavenging and metal-chelating activities. Also, this study exhibits a scientific shore for the significant antioxidant activity of taxifolin and its structure-activity insight. PMID:26147349

  9. Influence of HFE variants and cellular iron on monocyte chemoattractant protein-1

    Directory of Open Access Journals (Sweden)

    Simmons Zachary

    2009-02-01

    Full Text Available Abstract Background Polymorphisms in the MHC class 1-like gene known as HFE have been proposed as genetic modifiers of neurodegenerative diseases that include neuroinflammation as part of the disease process. Variants of HFE are relatively common in the general population and are most commonly associated with iron overload, but can promote subclinical cellular iron loading even in the absence of clinically identified disease. The effects of the variants as well as the resulting cellular iron dyshomeostasis potentially impact a number of disease-associated pathways. We tested the hypothesis that the two most common HFE variants, H63D and C282Y, would affect cellular secretion of cytokines and trophic factors. Methods We screened a panel of cytokines and trophic factors using a multiplexed immunoassay in human neuroblastoma SH-SY5Y cells expressing different variants of HFE. The influence of cellular iron secretion on the potent chemokine monocyte chemoattractant protein-1 (MCP-1 was assessed using ferric ammonium citrate and the iron chelator, desferroxamine. Additionally, an antioxidant, Trolox, and an anti-inflammatory, minocycline, were tested for their effects on MCP-1 secretion in the presence of HFE variants. Results Expression of the HFE variants altered the labile iron pool in SH-SY5Y cells. Of the panel of cytokines and trophic factors analyzed, only the release of MCP-1 was affected by the HFE variants. We further examined the relationship between iron and MCP-1 and found MCP-1 secretion tightly associated with intracellular iron status. A potential direct effect of HFE is considered because, despite having similar levels of intracellular iron, the association between HFE genotype and MCP-1 expression was different for the H63D and C282Y HFE variants. Moreover, HFE genotype was a factor in the effect of minocycline, a multifaceted antibiotic used in treating a number of neurologic conditions associated with inflammation, on MCP-1

  10. Determination of in vitro total phenolic, flavonoid contents and antioxidant capacity of the methanolic extract of Echium amoenum L.

    Directory of Open Access Journals (Sweden)

    Fathi H

    2016-06-01

    Full Text Available Introduction: In traditional and modern medicine, active ingredients of medicinal plants have many applications in food, pharmaceutical, medical and industry. Antioxidants are compounds that prevent the oxidation process in the cell. Echium amoenum L. is a plant which grows in the mountainous regions of Mazandaran. This plant has different biological effects such as sedation, anti-inflammation, antidepressant and cancer preventive properties in traditional medicine. The aim of this study was to determine the total phenolic, flavonoid contents and antioxidant capacity of the methanolic extract of E.amoenum plant. Methods:In this experimental laboratory study the content of total phenolic Using the folin-siokalatio reactive at 760 nm wavelength and flavonoid With the use of aluminum chloride reagent at 420nm of E.amoenum extract were measured and antioxidant capacities of different concentrations of the extract were evaluated. Results: The results showed that total phenolic content of the extract was 429±2μg gallic acid equivalent/ml and flavonoid content was 148.56±1.52μg quercetin equivalent/ml, respectively. The radical scavenging activity by 2, 2-diphenyl-1-picryl-hydrazyl hydrate (DPPH,inhibitory concentration of 50%(IC50,was determined 178.11 μg/ml. Assessment of the reducing ability of extract showed that the extract had more activity than vitamin C. The percent nitric oxide trap inhibition of the extract was 57.89% and power iron chelating properties was 51.74%,that showed statistically significant difference in comparison with vitamin C and Quercetin (P=0.0473 and (P=0.0096 respectively. Conclusion: According to the results, E.amoenum extract had remarkable antioxidant capacity and can be proposed as an antioxidant compound used in the manufacture of food and pharmaceutical products.

  11. Minocycline Attenuates Iron Neurotoxicity in Cortical Cell Cultures

    OpenAIRE

    Chen-Roetling, Jing; Chen, Lifen; Regan, Raymond F.

    2009-01-01

    Iron neurotoxicity may contribute to the pathogenesis of intracerebral hemorrhage (ICH). The tetracycline derivative minocycline is protective in ICH models, due putatively to inhibition of microglial activation. Although minocycline also chelates iron, its effect on iron neurotoxicity has not been reported, and was examined in this study. Cortical cultures treated with 10 μM ferrous sulfate for 24h sustained loss of most neurons and an increase in malondialdehyde. Minocycline prevented this ...

  12. Plasma thiobarbituric acid reactivity: reaction conditions and the role of iron, antioxidants and lipid peroxy radicals on the quantitation of plasma lipid peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Wade, C.R.; van Rij, A.M.

    1988-01-01

    The effects of Fe/sup 3 +/, lipid peroxy radicals and the antioxidant butylated hydroxytoluene on the 2-thiobarbituric (TBA) acid quantitation of plasma lipid peroxides were investigated. Whole plasma and plasma fractions prepared by trichloroacetic acid (TCA) protein precipitation and lipid extraction, demonstrated markedly differing TBA reactivities in the presence or absence of added Fe/sup 3 +/. Examination of the spectral profiles of the TBA reacted whole plasma and TCA precipitated fractions demonstrated the presence of interfering compounds which gave rise to an artifactual increase in lipid peroxide concentrations. In contrast the TBA reacted lipid extracts had low levels of interfering compounds that could be removed by our previously described high pressure liquid chromatographic method. Further characterization of the TBA reactivity of the lipid extract showed that Fe/sup 3 +/ at an optimal concentration of 0.5 mM was necessary for the quantitative decomposition of the lipid peroxides to the TBA reactive product malondialdehyde (MDA). However the presence of Fe/sup 3 +/ resulted in further peroxidation of any unsaturated lipids present.

  13. Update on the use of deferasirox in the management of iron overload

    Directory of Open Access Journals (Sweden)

    Ali Taher

    2009-10-01

    Full Text Available Ali Taher,1 Maria Domenica Cappellini21American University of Beirut, Beirut, Lebanon; 2Universitá di Milano, Policlinico Foundation IRCCS, Milan, ItalyAbstract: Regular blood transfusions as supportive care for patients with chronic anemia inevitably lead to iron overload as humans cannot actively remove excess iron. The cumulative effects of iron overload cause significant morbidity and mortality if not effectively treated with chelation therapy. Based on a comprehensive clinical development program, the once-daily, oral iron chelator deferasirox (Exjade® is approved for the treatment of transfusional iron overload in adult and pediatric patients with various transfusion-dependent anemias, including β-thalassemia and the myelodysplastic syndromes. Deferasirox dose should be titrated for each individual patient based on transfusional iron intake, current iron burden and whether the goal is to decrease or maintain body iron levels. Doses of >30 mg/kg/day have been shown to be effective with a safety profile consistent with that observed at doses <30 mg/kg/day. Recent data have highlighted the ability of deferasirox to decrease cardiac iron levels and to prevent the accumulation of iron in the heart. The long-term efficacy and safety of deferasirox for up to 5 years of treatment have now been established. The availability of this effective and generally well tolerated oral therapy represents a significant advance in the management of transfusional iron overload. Keywords: deferasirox, Exjade, oral, iron chelation, iron overload, cardiac iron 

  14. Evaluation of the Antioxidant and Antimicrobial Activities of Clary Sage (Salvia sclarea L.)

    OpenAIRE

    GÜLÇİN, İlhami

    2004-01-01

    The present work evaluates the antioxidant and antimicrobial activity of clary sage (CS) Salvia sclarea L. Antimicrobial, total antioxidant, DPPH radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities, reducing power, and total contents of phenolic compounds of dried herb samples extracted with chloroform and acetone were studied. The chloroform extract had stronger total antioxidant activity than the acetone extract and exhibited ...

  15. Cytosolic peroxidases protect the lysosome of bloodstream African trypanosomes from iron-mediated membrane damage.

    Directory of Open Access Journals (Sweden)

    Corinna Hiller

    2014-04-01

    Full Text Available African trypanosomes express three virtually identical non-selenium glutathione peroxidase (Px-type enzymes which preferably detoxify lipid-derived hydroperoxides. As shown previously, bloodstream Trypanosoma brucei lacking the mitochondrial Px III display only a weak and transient proliferation defect whereas parasites that lack the cytosolic Px I and Px II undergo extremely fast lipid peroxidation and cell lysis. The phenotype can completely be rescued by supplementing the medium with the α-tocopherol derivative Trolox. The mechanism underlying the rapid cell death remained however elusive. Here we show that the lysosome is the origin of the cellular injury. Feeding the px I-II knockout parasites with Alexa Fluor-conjugated dextran or LysoTracker in the presence of Trolox yielded a discrete lysosomal staining. Yet upon withdrawal of the antioxidant, the signal became progressively spread over the whole cell body and was completely lost, respectively. T. brucei acquire iron by endocytosis of host transferrin. Supplementing the medium with iron or transferrin induced, whereas the iron chelator deferoxamine and apo-transferrin attenuated lysis of the px I-II knockout cells. Immunofluorescence microscopy with MitoTracker and antibodies against the lysosomal marker protein p67 revealed that disintegration of the lysosome precedes mitochondrial damage. In vivo experiments confirmed the negligible role of the mitochondrial peroxidase: Mice infected with px III knockout cells displayed only a slightly delayed disease development compared to wild-type parasites. Our data demonstrate that in bloodstream African trypanosomes, the lysosome, not the mitochondrion, is the primary site of oxidative damage and cytosolic trypanothione/tryparedoxin-dependent peroxidases protect the lysosome from iron-induced membrane peroxidation. This process appears to be closely linked to the high endocytic rate and distinct iron acquisition mechanisms of the infective

  16. ANTIOXIDANT ACTIVITIES AND PHENOLIC PROFILE OF SIX MOROCCAN SELECTED HERBS

    Directory of Open Access Journals (Sweden)

    Madiha Bichra

    2013-02-01

    Full Text Available The present work evaluated the antioxidant capacity of six plants commonly used in traditional Moroccan medicine. The antioxidant capacity was estimated by DPPH test, ferrous ion chelating activity and ABTS test. As results, the highest antioxidant activities were found in Mentha suaveolens, Salvia officinalis and Mentha viridis. Different species showed significant differences in their total phenolic content (TPC. The highest level of phenolics was found in Salvia officinalis and the lowest in Pelargonium roseum. Linear correlation was found between TPC, especially the non-flavonoid content (NFC and the antioxidant activity. Qualitative and quantitative analyzes of major phenolics by reverse-phase high-performance liquid chromatography (RP-HPLC were also performed. On the basis of the obtained results, these studied medicinal herbs were found to serve as a potential source of natural antioxidants due to their richness in phenolic compounds and marked antioxidant activity.

  17. Ceramide-induced intracellular oxidant formation, iron signaling, and apoptosis in endothelial cells: protective role of endogenous nitric oxide.

    Science.gov (United States)

    Matsunaga, Toshiyuki; Kotamraju, Srigiridhar; Kalivendi, Shasi V; Dhanasekaran, Anuradha; Joseph, Joy; Kalyanaraman, B

    2004-07-01

    Sphingolipid ceramide (N-acetylsphingosine), a bioactive second messenger lipid, was shown to activate reactive oxygen species (ROS), mitochondrial oxidative damage, and apoptosis in neuronal and vascular cells. The proapoptotic effects of tumor necrosis factor-alpha, hypoxia, and chemotherapeutic drugs were attributed to increased ceramide formation. Here we investigated the protective role of nitric oxide (.NO) during hydrogen peroxide (H(2)O(2))-mediated transferrin receptor (TfR)-dependent iron signaling and apoptosis in C(2)-ceramide (C(2)-cer)-treated bovine aortic endothelial cells (BAECs). Addition of C(2)-cer (5-20 microm) to BAECs enhanced .NO generation. However, at higher concentrations of C(2)-cer (> or =20 microm), .NO generation did not increase proportionately. C(2)-cer (20-50 microm) also resulted in H(2)O(2)-mediated dichlorodihydrofluorescein oxidation, reduced glutathione depletion, aconitase inactivation, TfR overexpression, TfR-dependent uptake of (55)Fe, release of cytochrome c from mitochondria into cytosol, caspase-3 activation, and DNA fragmentation. N(w)-Nitro-l-arginine methyl ester (l-NAME), a nonspecific inhibitor of nitricoxide synthases, augmented these effects in BAECs at much lower (i.e. nonapoptotic) concentrations of C(2)-cer. The 26 S proteasomal activity in BAECs was slightly elevated at lower concentrations of C(2)-cer (10 microm). Intracellular scavengers of H(2)O(2), cell-permeable iron chelators, anti-TfR receptor antibody, or mitochondria-targeted antioxidant greatly abrogated C(2)-cer- and/or l-NAME-induced oxidative damage, iron signaling, and apoptosis. We conclude that C(2)-cer-induced H(2)O(2) and TfR-dependent iron signaling are responsible for its prooxidant and proapoptotic effects and that .NO exerts an antioxidative and cytoprotective role.

  18. Effect of iron on lipid peroxidation, and enzymatic and non-enzymatic antioxidants and bacoside-A content in medicinal plant Bacopa monnieri L.

    Science.gov (United States)

    Sinha, Sarita; Saxena, Rohit

    2006-03-01

    The effect of Fe was investigated in medicinally important plant, Bacopa monnieri L. and the response on malondialdehyde (MDA) content, superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) was found different in roots and leaves of the metal treated plants. Iron induced stress was observed as indicated by high level of lipid peroxidation, being more steep increase in leaves than roots. In roots, SOD activity was found to increase in metal treated plants except 80 and 160 microM at 72 h, whereas, it decreased in leaves except 10 and 40 microM after 48 h as compared to their respective controls. Among H2O2 eliminating enzymes, POD activity increased in roots, however, it decreased in leaves except at 10 and 40 microM Fe after 48 h as compared to control. At 24 and 48 h, APX activity and ascorbic acid content followed the similar trend and were found to increase in both parts of the metal treated plants as compared to their respective controls. The level of cysteine content in the roots increased at initial period of exposure; however, no marked change in its content was noticed in leaves. In both roots and leaves, non-protein thiol content was found to increase except at higher metal concentrations at 72 h. The data of proline content have shown significant (pbacoside-A (active constituent) content in metal treated plants increases, therefore, it is advisable to assess the biological activity of the plants before using for medicinal purposes, particularly in developing countries.

  19. Protective effects of ion-imprinted chitooligosaccharides as uranium-specific chelating agents against the cytotoxicity of depleted uranium in human kidney cells

    International Nuclear Information System (INIS)

    Occupational internal contamination with depleted uranium (DU) compounds can induce radiological and chemical toxicity, and an effective and specific uranium-chelating agent for clinical use is urgently needed. The purpose of this study was to investigate whether a series of synthesized water-soluble metal-ion-imprinted chitooligosaccharides can be used as uranium-specific chelating agents, because the chitooligosaccharides have excellent heavy metal ion chelation property and the ion-imprinting technology can improve the selective recognition of template ions. DU-poisoned human renal proximal tubule epithelium cells (human kidney 2 cells, HK-2) were used to assess the detoxification of these chitooligosaccharides. The DU-chelating capacity and selectivity of the chitooligosaccharides were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Cell viability, cellular accumulation of DU, membrane damage, DNA damage, and morphological changes in the cellular ultrastructure were examined to assess the detoxification of these chitooligosaccharides. The results showed that the Cu2+-imprinted chitooligosaccharides, especially the Cu2+-imprinted glutaraldehyde-crosslinked carboxymethyl chitooligosaccharide (Cu-Glu-CMC), chelated DU effectively and specifically, and significantly reduced the loss of cell viability induced by DU and reduced cellular accumulation of DU in a dose-dependent manner, owing to their chelation of DU outside cells and their prevention of DU internalization. The ultrastructure observation clearly showed that Cu-Glu-CMC-chelated-DU precipitates, mostly outside cells, were grouped in significantly larger clusters, and they barely entered the cells by endocytosis or in any other way. Treatment with Cu-Glu-CMC also increased the activity of antioxidant enzymes, and reduced membrane damage and DNA damage induced by DU oxidant injury. Cu-Glu-CMC was more effective than the positive control drug, diethylenetriaminepentaacetic acid (DTPA), in

  20. Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

    Science.gov (United States)

    Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

    2002-01-16

    Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved. PMID:11782196

  1. Influence of chelating ligands on arsenic uptake by hydroponically grown rice seedlings (Oryza sativa L.): a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Mohammad A.; Hasegawa, Hiroshi; Ueda, Kazumasa; Maki, Teruya [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa (Japan); Rahman, M.M. [Department of Botany, Faculty of Biological Sciences, Jahangirnagar University, Savar, Dhaka (Bangladesh)

    2008-06-15

    Ferric (oxyhydro-)oxides (FeO{sub x}) precipitate in the rhizosphere at neutral or alkaline pH and are adsorbed on the plant root surfaces. Consequently, the higher binding affinity of arsenate to FeO{sub x} and the low iron phytoavailability of the precipitated FeO{sub x} make the phytoremediation of arsenic difficult. In the present study, the influence of chelating ligands on arsenic and iron uptake by hydroponically grown rice seedlings (Oryza sativa L.) was investigated. When chelating ligands were not treated to the growth medium, about 63 and 71% of the total arsenic and iron were distributed in the root extract (outer root surfaces) of rice, respectively. On the other hand, ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS) and hydroxyiminodisuccinic acid (HIDS) desorbed a significant amount of arsenic from FeO{sub x} of the outer root surfaces. Therefore, the uptake of arsenic and iron into the roots and their subsequent translocation to the shoots of the rice seedlings increased significantly. The order of increasing arsenic uptake by chelating ligands was HIDS > EDTA > EDDS. Methylglycinediacetic acid (MGDA) and iminodisuccinic acid (IDS) might not be effective in arsenic solubilization from FeO{sub x}. The results suggest that EDDS and HIDS would be a good and environmentally safe choice to accelerate arsenic phytoavailability in the phytoremediation process because of their biodegradability and would be a competent alternative to the widely used non-biodegradable and environmentally persistent EDTA. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  2. Differing features of proteins in membranes may result in antioxidant or prooxidant action: opposite effects on lipid peroxidation of alcohol dehydrogenase and albumin in liposomal systems.

    Science.gov (United States)

    Riedl, A; Shamsi, Z; Anderton, M; Goldfarb, P; Wiseman, A

    1996-02-01

    The influence of 3 thiol-containing compounds, bovine serum albumin (fatty acid free: BSA), glutathione (GSH) and yeast alcohol dehydrogenase (YADH) on lipid peroxidation in multilamellar liposomes, prepared from ox-brain phospholipid, was investigated. Thiol-compounds were added either before liposome formation, or after liposome formation; and their effects compared to a positive control. Bovine serum albumin (BSA), an acidic hydrophilic protein, displays a small, concentration dependent, antioxidant effect when added to preformed liposomes. A much larger antioxidant effect was observed when the BSA was entrapped inside the liposome, by adding BSA just prior to liposome preparation. In contrast, a Zn(2+) containing redox enzyme, YADH, a basic hydrophobic membrane-associating protein, displays a large pro-oxidant effect at much lower concentrations especially when entrapped inside the liposome. This was observed also with GSH; but per mole of -SH, YADH was about 18 times as powerful a pro-oxidant perhaps because of structural changes to the membrane. Oxidized glutathione and N-acetylcysteine were also pro-oxidant (cysteine and cystine showed little effect). Formation of thiyl radicals may occur in the presence of iron ions with these pro-oxidant sulphur-containing compounds. Partial protection against lipid peroxidation was observed with EDTA, desferrioxamine and protoporphyrin (IX), potent iron-chelating agents.

  3. Development of an upconverting chelate assay

    Science.gov (United States)

    Xiao, Xudong; Haushalter, Jeanne P.; Kotz, Kenneth T.; Faris, Gregory W.

    2005-04-01

    We report progress on performing a cell-based assay for the detection of EGFR on cell surfaces by using upconverting chelates. An upconversion microscope has been developed for performing assays and testing optical response. A431 cells are labeled with europium DOTA and imaged using this upconverting microscope.

  4. Questions and Answers on Unapproved Chelation Products

    Science.gov (United States)

    ... it Email Print The U.S. Food and Drug Administration (FDA) advises consumers to be wary of so-called “chelation” products that are marketed over-the-counter (OTC) to prevent or treat diseases. Companies are marketing unapproved OTC chelation therapy products to ...

  5. Aceruloplasminaemia: a rare but important cause of iron overload.

    Science.gov (United States)

    Doyle, Adam; Rusli, Ferry; Bhathal, Prithi

    2015-01-01

    We present a case of a 20-year-old man referred to our service with iron overload and mildly deranged liver biochemistry. Although liver histopathology was consistent with haemochromatosis, iron studies were not consistent with this diagnosis. Serum ceruloplasmin levels were undetectable, leading to a diagnosis of aceruloplasminaemia. Unlike other iron overload disorders, neurological complications are a unique feature of this illness, and often irreversible, once established. The patient was treated with iron chelation prior to the onset of neurological injury, and experienced progressive normalisation of his ferritin and liver biochemistry. This is one of the youngest diagnosed cases in the published literature and, crucially, was a rare case of diagnosis and treatment prior to the onset of neurological sequelae. This is presented alongside a review of previously published cases of aceruloplasminaemia, including responses to iron chelation therapy. PMID:25976187

  6. Phytochelators Intended for Clinical Use in Iron Overload, Other Diseases of Iron Imbalance and Free Radical Pathology

    Directory of Open Access Journals (Sweden)

    Christina N. Kontoghiorghe

    2015-11-01

    Full Text Available Iron chelating drugs are primarily and widely used in the treatment of transfusional iron overload in thalassaemia and similar conditions. Recent in vivo and clinical studies have also shown that chelators, and in particular deferiprone, can be used effectively in many conditions involving free radical damage and pathology including neurodegenerative, renal, hepatic, cardiac conditions and cancer. Many classes of phytochelators (Greek: phyto (φυτό—plant, chele (χηλή—claw of the crab with differing chelating properties, including plant polyphenols resembling chelating drugs, can be developed for clinical use. The phytochelators mimosine and tropolone have been identified to be orally active and effective in animal models for the treatment of iron overload and maltol for the treatment of iron deficiency anaemia. Many critical parameters are required for the development of phytochelators for clinical use including the characterization of the therapeutic targets, ADMET, identification of the therapeutic index and risk/benefit assessment by comparison to existing therapies. Phytochelators can be developed and used as main, alternative or adjuvant therapies including combination therapies with synthetic chelators for synergistic and or complimentary therapeutic effects. The development of phytochelators is a challenging area for the introduction of new pharmaceuticals which can be used in many diseases and also in ageing. The commercial and other considerations for such development have great advantages in comparison to synthetic drugs and could also benefit millions of patients in developing countries.

  7. Monoclonal antibodies against the iron regulated outer membrane Proteins of Acinetobacter baumannii are bactericidal

    OpenAIRE

    Goel, Vikas Kumar; Kapil, Arti

    2001-01-01

    Background Iron is an important nutrient required by all forms of life.In the case of human hosts,the free iron availability is 10-18M,which is far less than what is needed for the survival of the invading bacterial pathogen.To survive in such conditions, bacteria express new proteins in their outer membrane and also secrete iron chelators called siderophores. Results/ Discussion Acinetobacter baumannii ATCC 19606, a nosocomial pathogen which grows under iron restricted conditions, expresses ...

  8. Minocycline Attenuates Iron-Induced Brain Injury.

    Science.gov (United States)

    Zhao, Fan; Xi, Guohua; Liu, Wenqaun; Keep, Richard F; Hua, Ya

    2016-01-01

    Iron plays an important role in brain injury after intracerebral hemorrhage (ICH). Our previous study found minocycline reduces iron overload after ICH. The present study examined the effects of minocycline on the subacute brain injury induced by iron. Rats had an intracaudate injection of 50 μl of saline, iron, or iron + minocycline. All the animals were euthanized at day 3. Rat brains were used for immunohistochemistry (n = 5-6 per each group) and Western blotting assay (n = 4). Brain swelling, blood-brain barrier (BBB) disruption, and iron-handling proteins were measured. We found that intracerebral injection of iron resulted in brain swelling, BBB disruption, and brain iron-handling protein upregulation (p < 0.05). The co-injection of minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p < 0.01). Albumin, a marker of BBB disruption, was measured by Western blot analysis. Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p < 0.01). Iron-handling protein levels in the brain, including ceruloplasmin and transferrin, were reduced in the minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism. PMID:26463975

  9. Parkinson's Disease: The Mitochondria-Iron Link.

    Science.gov (United States)

    Muñoz, Yorka; Carrasco, Carlos M; Campos, Joaquín D; Aguirre, Pabla; Núñez, Marco T

    2016-01-01

    Mitochondrial dysfunction, iron accumulation, and oxidative damage are conditions often found in damaged brain areas of Parkinson's disease. We propose that a causal link exists between these three events. Mitochondrial dysfunction results not only in increased reactive oxygen species production but also in decreased iron-sulfur cluster synthesis and unorthodox activation of Iron Regulatory Protein 1 (IRP1), a key regulator of cell iron homeostasis. In turn, IRP1 activation results in iron accumulation and hydroxyl radical-mediated damage. These three occurrences-mitochondrial dysfunction, iron accumulation, and oxidative damage-generate a positive feedback loop of increased iron accumulation and oxidative stress. Here, we review the evidence that points to a link between mitochondrial dysfunction and iron accumulation as early events in the development of sporadic and genetic cases of Parkinson's disease. Finally, an attempt is done to contextualize the possible relationship between mitochondria dysfunction and iron dyshomeostasis. Based on published evidence, we propose that iron chelation-by decreasing iron-associated oxidative damage and by inducing cell survival and cell-rescue pathways-is a viable therapy for retarding this cycle.

  10. Parkinson's Disease: The Mitochondria-Iron Link.

    Science.gov (United States)

    Muñoz, Yorka; Carrasco, Carlos M; Campos, Joaquín D; Aguirre, Pabla; Núñez, Marco T

    2016-01-01

    Mitochondrial dysfunction, iron accumulation, and oxidative damage are conditions often found in damaged brain areas of Parkinson's disease. We propose that a causal link exists between these three events. Mitochondrial dysfunction results not only in increased reactive oxygen species production but also in decreased iron-sulfur cluster synthesis and unorthodox activation of Iron Regulatory Protein 1 (IRP1), a key regulator of cell iron homeostasis. In turn, IRP1 activation results in iron accumulation and hydroxyl radical-mediated damage. These three occurrences-mitochondrial dysfunction, iron accumulation, and oxidative damage-generate a positive feedback loop of increased iron accumulation and oxidative stress. Here, we review the evidence that points to a link between mitochondrial dysfunction and iron accumulation as early events in the development of sporadic and genetic cases of Parkinson's disease. Finally, an attempt is done to contextualize the possible relationship between mitochondria dysfunction and iron dyshomeostasis. Based on published evidence, we propose that iron chelation-by decreasing iron-associated oxidative damage and by inducing cell survival and cell-rescue pathways-is a viable therapy for retarding this cycle. PMID:27293957

  11. Activation of the NLRP3 inflammasome by cellular labile iron.

    Science.gov (United States)

    Nakamura, Kyohei; Kawakami, Toru; Yamamoto, Naoki; Tomizawa, Miyu; Fujiwara, Tohru; Ishii, Tomonori; Harigae, Hideo; Ogasawara, Kouetsu

    2016-02-01

    Cellular labile iron, which contains chelatable redox-active Fe(2+), has been implicated in iron-mediated cellular toxicity leading to multiple organ dysfunction. Iron homeostasis is controlled by monocytes/macrophages through their iron recycling and storage capacities. Furthermore, iron sequestration by monocytes/macrophages is regulated by pro-inflammatory cytokines including interleukin-1, highlighting the importance of these cells in the crosstalk between inflammation and iron homeostasis. However, a role for cellular labile iron in monocyte/macrophage-mediated inflammatory responses has not been defined. Here we describe how cellular labile iron activates the NLRP3 inflammasome in human monocytes. Stimulation of lipopolysaccharide-primed peripheral blood mononuclear cells with ferric ammonium citrate increases the level of cellular Fe(2+) levels in monocytes and induces production of interleukin-1β in a dose-dependent manner. This ferric ammonium citrate-induced interleukin-1β production is dependent on caspase-1 and is significantly inhibited by an Fe(2+)-specific chelator. Ferric ammonium citrate consistently induced interleukin-1β secretion in THP1 cells, but not in NLRP3-deficient THP1 cells, indicating a requirement for the NLRP3 inflammasome. Additionally, activation of the inflammasome is mediated by potassium efflux, reactive oxygen species-mediated mitochondrial dysfunction, and lysosomal membrane permeabilization. Thus, these results suggest that monocytes/macrophages not only sequestrate iron during inflammation, but also mediate inflammation in response to cellular labile iron, which provides novel insights into the role of iron in chronic inflammation. PMID:26577567

  12. Effect of adding ball-milled achenes to must on bioactive compounds and antioxidant activities in fruit wine.

    Science.gov (United States)

    Lee, Pao-Ju; Chen, Shaun

    2016-03-01

    This study reports the utilization of ball-milled achenes in fermentation to increase the levels of ellagic acid and total phenol content, as well as to enhance the antioxidant capacity of strawberry wine. Achenes were micronized using ball-milling process, and then added to strawberry must prior to fermentation. The effects of the addition of ball-milled achenes on the ellagic acid and total phenol content in strawberry wine were determined, and the free radical scavenging and iron chelation activities were also analyzed. Quality attributes and acceptance were studied in comparison with a leading commercial strawberry wine for market application. The particle sizes of achenes were reduced from 1.1 mm to 400 nm after 30 min of ball-milling, and this led to an increase in the amount of extracted ellagic acid from 550.72 to 915.24 μg/g. The addition of ball-milled achenes to must led to a 19.72 % and 52.37 % increase in ellagic acid and total phenol content in strawberry wine, respectively. The increase in bioactive compounds resulted in increases of 54.09 %, 51.49 % and 56.97 % in ABTS and DPPH radical scavenging, and ferrous ion chelating activities, respectively. Although the commercial strawberry wine showed greater aroma intensity, no significant differences in overall quality and acceptance among the conventional process, added ball-milled achenes and the leading commercial strawberry wines were found. This study demonstrates that supplementation of ball-milled achenes in fermentation can be beneficial in increasing the levels of bioactive compounds and antioxidative capacity, indicating a good market potential. PMID:27570280

  13. Second international round robin for the quantification of serum non-transferrin-bound iron and labile plasma iron in patients with iron-overload disorders.

    Science.gov (United States)

    de Swart, Louise; Hendriks, Jan C M; van der Vorm, Lisa N; Cabantchik, Z Ioav; Evans, Patricia J; Hod, Eldad A; Brittenham, Gary M; Furman, Yael; Wojczyk, Boguslaw; Janssen, Mirian C H; Porter, John B; Mattijssen, Vera E J M; Biemond, Bart J; MacKenzie, Marius A; Origa, Raffaella; Galanello, Renzo; Hider, Robert C; Swinkels, Dorine W

    2016-01-01

    Non-transferrin-bound iron and its labile (redox active) plasma iron component are thought to be potentially toxic forms of iron originally identified in the serum of patients with iron overload. We compared ten worldwide leading assays (6 for non-transferrin-bound iron and 4 for labile plasma iron) as part of an international inter-laboratory study. Serum samples from 60 patients with four different iron-overload disorders in various treatment phases were coded and sent in duplicate for analysis to five different laboratories worldwide. Some laboratories provided multiple assays. Overall, highest assay levels were observed for patients with untreated hereditary hemochromatosis and β-thalassemia intermedia, patients with transfusion-dependent myelodysplastic syndromes and patients with transfusion-dependent and chelated β-thalassemia major. Absolute levels differed considerably between assays and were lower for labile plasma iron than for non-transferrin-bound iron. Four assays also reported negative values. Assays were reproducible with high between-sample and low within-sample variation. Assays correlated and correlations were highest within the group of non-transferrin-bound iron assays and within that of labile plasma iron assays. Increased transferrin saturation, but not ferritin, was a good indicator of the presence of forms of circulating non-transferrin-bound iron. The possibility of using non-transferrin-bound iron and labile plasma iron measures as clinical indicators of overt iron overload and/or of treatment efficacy would largely depend on the rigorous validation and standardization of assays. PMID:26385212

  14. Influence of Chelating Agents on Chromium Fate in Sediment

    Institute of Scientific and Technical Information of China (English)

    WANGXIAOCHANG; SUNJINHE; 等

    1996-01-01

    A laboratory investigation on reaction between chelating agents and chromium was conducted to evaluate the effect of chelating agents on the adsorption and desorption of chromium in sediment.The amount of adsorbed chromium(VI) in sediment decreased slightly by 5%-10% because of addition of chelating agents.Chelating agents inhibited the removal of Cr(Ⅲ)by sediment from solutions and the inhibiting effect was in the order:citric acid>tartaric acid>EDTA,Salicylic acid.No effect of chelating agents on desorption of chromium in sediment was observed.

  15. Synthesis of Iminodiacetate Functionalized Polypropylene Films and Their Efficacy as Antioxidant Active-Packaging Materials.

    Science.gov (United States)

    Lin, Zhuangsheng; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-06-01

    The introduction of metal-chelating ligands to the food-contact surface of packaging materials may enable the removal of synthetic chelators (e.g., ethylenediamine tetra-acetic acid (EDTA)) from food products. In this study, the metal-chelating ligand iminodiacetate (IDA) was covalently grafted onto polypropylene surfaces to produce metal-chelating active-packaging films. The resulting films were able to chelate 138.1 ± 26 and 210.0 ± 28 nmol/cm(2) Fe(3+) and Cu(2+) ions, respectively, under acidic conditions (pH 3.0). The films demonstrated potent antioxidant efficacy in two model food systems. In an emulsified-oil system, the chelating materials extended the lag phase of both lipid hydroperoxide and hexanal formation from 5 to 25 days and were as effective as EDTA. The degradation half-life of ascorbic acid in an aqueous solution was extended from 5 to 14 days. This work demonstrates the potential application of surface-grafted chelating IDA ligands as effective antioxidant active food-packaging materials. PMID:27243793

  16. Pentaarylcyclopentadiene und chirale Ruthenium-Chelat-Komplexe

    OpenAIRE

    Kanthak, Matthias

    2010-01-01

    Die Synthese von mono-ortho-funktionalisierten Pentaphenylcyclopentadienen gelang durch eine Abwandlung der klassischen Tetracyclon-Route. Durch die Umsetzung der funktionalisierten Cyclopentadiene mit Ru3(CO)12 als Metallquelle konnten entsprechende Ruthenium-Komplexe erhalten werden. Die geeignete Wahl der Substituenten an der Phenylgruppe erlaubte die Bildung von Chelat-Komplexen mit chirotopem Metallzentrum. Enantiomerenreine Oxazolin-Seitenarme führten zu diastereomerenreinen...

  17. Federal regulation of unapproved chelation products.

    Science.gov (United States)

    Lee, Charles E

    2013-12-01

    Chelation products can be helpful in the treatment of metal poisoning. However, many unapproved products with unproven effectiveness and safety are marketed to consumers, frequently via the internet. This paper describes the primary responsibility of the Health Fraud and Consumer Outreach Branch of the United States Food and Drug Administration to identify and address health fraud products. Efforts to prevent direct and indirect hazards to the population's health through regulatory actions are described.

  18. Antioxidant Effect of Stryphnodendron rotundifolium Martius Extracts from Cariri-Ceará State (Brazil: Potential Involvement in Its Therapeutic Use

    Directory of Open Access Journals (Sweden)

    Aline Augusti Boligon

    2012-01-01

    Full Text Available Stryphnodendron rotundifolium is a phytotherapic used in the northeast of Brazil for the treatment of inflammatory processes which normally are associated with oxidative stress. Consequently, we have tested the antioxidant properties of hydroalcoholic (HAB and aqueous extracts (AB from the bark and aqueous extract (AL from the leaves of Stryphnodendron rotundifolium to determine a possible association between antioxidant activity and the popular use of this plant. Free radical scavenger properties were assessed by the quenching of 1′,1′-diphenil-2-picrylhydrazyl (DPPH and the calculated IC50 were: HAB = 5.4 ± 0.7, AB = 12.0 ± 2.6, and AL = 46.3 ± 12.3 µg/mL. Total phenolic contents were: HAB = 102.7 ± 2.8, AB = 114.4 ± 14.6, and AL = 93.8 ± 9.1 µg/mg plant. HPLC/DAD analyses indicated that gallic acid, catechin, rutin and caffeic acid were the major components of the crude extracts of S. rotundifolium. Plant extracts inhibited Fe(II-induced lipid peroxidation in brain homogenates. Iron chelation was also investigated and only HBA exhibited a weak activity. Taken together, the results suggest that S. rotundifolium could be considered an effective agent in the prevention of diseases associated with oxidative stress.

  19. Antioxidant effect of Stryphnodendron rotundifolium Martius extracts from Cariri-Ceará State (Brazil): potential involvement in its therapeutic use.

    Science.gov (United States)

    da Costa, José Galberto Martins; Leite, Gerlânia de Oliveira; Dubois, Albys Ferrer; Seeger, Rodrigo Lopes; Boligon, Aline Augusti; Athayde, Margareth Linde; Campos, Adriana Rolim; da Rocha, João Batista Teixeira

    2012-01-01

    Stryphnodendron rotundifolium is a phytotherapic used in the northeast of Brazil for the treatment of inflammatory processes which normally are associated with oxidative stress. Consequently, we have tested the antioxidant properties of hydroalcoholic (HAB) and aqueous extracts (AB) from the bark and aqueous extract (AL) from the leaves of Stryphnodendron rotundifolium to determine a possible association between antioxidant activity and the popular use of this plant. Free radical scavenger properties were assessed by the quenching of 1',1'-diphenil-2-picrylhydrazyl (DPPH) and the calculated IC(50) were: HAB = 5.4 ± 0.7, AB = 12.0 ± 2.6, and AL = 46.3 ± 12.3 µg/mL. Total phenolic contents were: HAB = 102.7 ± 2.8, AB = 114.4 ± 14.6, and AL = 93.8 ± 9.1 µg/mg plant). HPLC/DAD analyses indicated that gallic acid, catechin, rutin and caffeic acid were the major components of the crude extracts of S. rotundifolium. Plant extracts inhibited Fe(II)-induced lipid peroxidation in brain homogenates. Iron chelation was also investigated and only HBA exhibited a weak activity. Taken together, the results suggest that S. rotundifolium could be considered an effective agent in the prevention of diseases associated with oxidative stress.

  20. Iron, anemia and hepcidin in malaria

    Directory of Open Access Journals (Sweden)

    Natasha eSpottiswoode

    2014-05-01

    Full Text Available Malaria and iron have a complex but important relationship. Plasmodium proliferation requires iron, both during the clinically silent liver stage of growth and in the disease-associated phase of erythrocyte infection. Precisely how the protozoan acquires its iron from its mammalian host remains unclear, but iron chelators can inhibit pathogen growth in vitro and in animal models. In humans, iron deficiency appears to protect against severe malaria, while iron supplementation increases risks of infection and disease. Malaria itself causes profound disturbances in physiological iron distribution and utilization, through mechanisms that include hemolysis, release of heme, dyserythropoiesis, anemia, deposition of iron in macrophages, and inhibition of dietary iron absorption. These effects have significant consequences. Malarial anemia is a major global health problem, especially in children, that remains incompletely understood and is not straightforward to treat. Furthermore, the changes in iron metabolism during a malaria infection may modulate susceptibility to coinfections. The release of heme and accumulation of iron in granulocytes may explain increased vulnerability to non-typhoidal Salmonella during malaria. The redistribution of iron away from hepatocytes and into macrophages may confer host resistance to superinfection, whereby blood-stage parasitemia prevents the development of a second liver-stage Plasmodium infection in the same organism. Key to understanding the pathophysiology of iron metabolism in malaria is the activity of the iron regulatory hormone hepcidin. Hepcidin is upregulated during blood-stage parasitemia and likely mediates much of the iron redistribution that accompanies disease. Understanding the regulation and role of hepcidin may offer new opportunities to combat malaria and formulate better approaches to treat anemia in the developing world.

  1. Oxidants and antioxidants in cardiovascular disease

    OpenAIRE

    Ekblom, Kim

    2010-01-01

    Background Cardiovascular diseases, including myocardial infarction and stroke, are the main reason of death in Sweden and Western Europe. High iron stores are believed to produce oxygen radicals, which is the presumed putative mechanism behind lipid peroxidation, atherosclerosis and subsequent cardiovascular disease. Iron levels are associated with the hemochromatosis associated HFE single nucleotide polymorphisms C282Y and H63D. Bilirubin is an antioxidant present in relatively high levels ...

  2. Antioxidant activity of hydrolysates of deer bone gelatin in a liposome

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yuhong; GAO Tian; ZHANG Ligang

    2007-01-01

    Gelatin extracted from deer bone was hydrolyzed for 3.5-120 min. The degree of hydrolysis was higher from Alcalase-hydrolyzed gelatin than that from neutral proteinase-hydrolyzed gelatin. Alcalase-hydrolyzed gelatin exhibited a stronger antioxidant activity than that of neutral proteinase-hydrolyzed gelatin. Hydrolysates showed strong radical-scavenging ability and Fe2+-chelating activity, both of which were influenced by hydrolysis time. Although nonhydrolyzed gelatin displayed a certain antioxidative effect, it was far less than that of hydrolysates. The hydrolysates of deer bone gelatin can work as a radical stabilizer and metal ion chelator to inhibit lipid oxidation.

  3. Iron-Catalyzed C-H Functionalization Processes.

    Science.gov (United States)

    Cera, Gianpiero; Ackermann, Lutz

    2016-10-01

    Iron-catalyzed C-H activation has recently emerged as an increasingly powerful tool for the step-economical transformation of unreactive C-H bonds. Particularly, the recent development of low-valent iron catalysis has set the stage for novel C-H activation strategies via chelation assistance. The low-cost, natural abundance, and low toxicity of iron prompted its very recent application in organometallic C-H activation catalysis. An overview of the use of iron catalysis in C-H activation processes is summarized herein up to May 2016. PMID:27573499

  4. Treating thalassemia major-related iron overload: the role of deferiprone.

    Science.gov (United States)

    Berdoukas, Vasilios; Farmaki, Kallistheni; Carson, Susan; Wood, John; Coates, Thomas

    2012-01-01

    Over the last 20 years, management for thalassemia major has improved to the point where we predict that patients' life expectancy will approach that of the normal population. These outcomes result from safer blood transfusions, the availability of three iron chelators, new imaging techniques that allow specific organ assessment of the degree of iron overload, and improvement in the treatment of hepatitis. In October 2011, the Food and Drug Administration licensed deferiprone, further increasing the available choices for iron chelation in the US. The ability to prescribe any of the three chelators as well as their combinations has led to more effective reduction of total body iron. The ability to determine the amount of iron in the liver and heart by magnetic resonance imaging allows the prescription of the most appropriate chelation regime for patients and to reconsider what our aims with respect to total body iron should be. Recent evidence from Europe has shown that by normalizing iron stores not only are new morbidities prevented but also reversal of many complications such as cardiac failure, hypothyroidism, hypogonadism, impaired glucose tolerance, and type 2 diabetes can occur, improving survival and patients' quality of life. The most effective way to achieve normal iron stores seems to be with the combination of deferoxamine and deferiprone. Furthermore, outcomes should continue to improve in the future. Starting relative intensive chelation in younger children may prevent short stature and abnormal pubertal maturation as well as other iron-related morbidities. Also, further information should become available on the use of other combinations in chelation treatment, some of which have been used only in a very limited fashion to date. All these advances in management require absolute cooperation and understanding of parents, children, and, subsequently, the patients themselves. Only with such cooperation can normal long-term survival be achieved, as

  5. Protection against SR 4233 (tirapazamine) aerobic cytotoxicity by the metal chelators desferrioxamine and tiron

    International Nuclear Information System (INIS)

    Metal chelating agents and antioxidants were evaluated as potential protectors against aerobic SR 4233 cytotoxicity in Chinese hamster V79 cells. The differential protection of aerobic and hypoxic cells by two metal chelators, desferrrioxamine and Tiron, is discussed in the context of their potential use in the on-going clinical trials with SR 4233. Cytotoxicity was evaluated using clonogenic assay. SR 4233 exposure was done in glass flasks as a function of time either alone or in the presence of the following agents: superoxide dismutase, catalase, 5,5-dimethyl-1-pyrroline, Trolox, ICRF-187, desferrioxamine, Tiron (1,2-dihydroxybenzene-3,5-disulfonate), and ascorbic acid. Experiments done under hypoxic conditions were carried out in specially designed glass flasks that were gassed with humidified nitrogen/carbon dioxide mixture and with a side-arm reservoir from which SR 4233 was added to cell media after hypoxia was obtained. Electron paramagnetic resonance studies were also performed. Electron paramagnetic resonance and spectrophotometry experiments suggest that under aerobic conditions SR 4233 undergoes futile redox cycling to produce superoxide. Treatment of cells during aerobic exposure to SR 4233 with the enzymes superoxide dismutase and catalase, the spin trapping agent DMPO, the water-soluble vitamin E analog Trolox, and the metal chelator ICRF-187 provided little or no protection against aerobic SR 4233 cytotoxicity. However, two other metal chelators, desferrioxamine and Tiron afforded significant protection against minimal protection to hypoxic cells treated with SR 4233. One potential mechanism of aerobic cytotoxicity is redox cycling of SR 4233 with molecular oxygen resulting in several potentially toxic oxidative species that overburden the intrinsic intracellular detoxification systems such as superoxide dismutase, catalase, and glutathione peroxidase. 23 refs., 4 figs., 1 tab

  6. Iron deficiency.

    Science.gov (United States)

    Scrimshaw, N S

    1991-10-01

    The world's leading nutritional problem is iron deficiency. 66% of children and women aged 15-44 years in developing countries have it. Further, 10-20% of women of childbearing age in developed countries are anemic. Iron deficiency is identified with often irreversible impairment of a child's learning ability. It is also associated with low capacity for adults to work which reduces productivity. In addition, it impairs the immune system which reduces the body's ability to fight infection. Iron deficiency also lowers the metabolic rate and the body temperature when exposed to cold. Hemoglobin contains nearly 73% of the body's iron. This iron is always being recycled as more red blood cells are made. The rest of the needed iron does important tasks for the body, such as binds to molecules that are reservoirs of oxygen for muscle cells. This iron comes from our diet, especially meat. Even though some plants, such as spinach, are high in iron, the body can only absorb 1.4-7% of the iron in plants whereas it can absorb 20% of the iron in red meat. In many developing countries, the common vegetarian diets contribute to high rates of iron deficiency. Parasitic diseases and abnormal uterine bleeding also promote iron deficiency. Iron therapy in anemic children can often, but not always, improve behavior and cognitive performance. Iron deficiency during pregnancy often contributes to maternal and perinatal mortality. Yet treatment, if given to a child in time, can lead to normal growth and hinder infections. However, excess iron can be damaging. Too much supplemental iron in a malnourished child promotes fatal infections since the excess iron is available for the pathogens use. Many countries do not have an effective system for diagnosing, treating, and preventing iron deficiency. Therefore a concerted international effort is needed to eliminate iron deficiency in the world.

  7. Soy protein hydrolysis with microbial protease to improve antioxidant and functional properties.

    Science.gov (United States)

    de Oliveira, Cibele Freitas; Corrêa, Ana Paula Folmer; Coletto, Douglas; Daroit, Daniel Joner; Cladera-Olivera, Florencia; Brandelli, Adriano

    2015-05-01

    Soybean proteins are widely used as nutritional and functional food ingredients. This investigation evaluated through a 2(3) central composite design the effect of three variables (pH, temperature and enzyme/substrate (E/S) ratio) on the production of soy protein isolate (SPI) hydrolysates with a microbial protease. Soluble peptides, antioxidant activity, and foaming and emulsifying capabilities of the hydrolysates were analyzed. All variables, as well as their interactions, were significant for the soluble peptides content of SPI hydrolysates. Optimal conditions for obtaining soluble peptides were around 30-35 °C, pH 6.5-9.5, and E/S ratios of 1,650-6,300 U g(-1). SPI hydrolysates produced at 30-45 °C, pH 8.0-9.5, and E/S ratios of 4,000-8,000 U g(-1) showed higher capacity to scavenge the 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical. Models for soluble peptides and ABTS activity of hydrolysates were obtained. In the range studied, the variables had not significant influence on the ability of hydrolysates to scavenge the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. SPI hydrolysates also presented reducing power and ability to chelate iron. Hydrolysis temperature was significant for the Fe(2+)-chelating ability of hydrolysates. Temperature of hydrolysis was significant for the foaming capacity of hydrolysates, with higher values observed at 45 °C and 8,000 U g(-1). For emulsifying capacity, only E/S ratio presented a significant effect. Temperature and E/S ratio appeared to be more significant variables influencing the properties of the SPI hydrolysates. The results of this study indicate that specific hydrolysis conditions should be selected to obtain SPI hydrolysates with preferred characteristics.

  8. Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

    Science.gov (United States)

    Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

    2003-08-25

    Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3

  9. Antiglycation and antioxidant properties of soy sauces.

    Science.gov (United States)

    Mashilipa, Changwe; Wang, Qiuyu; Slevin, Mark; Ahmed, Nessar

    2011-12-01

    Diabetes-induced hyperglycemia increases formation of advanced glycation end products (AGEs) and metal-catalyzed production of free radicals. This study compared the antioxidant capacities of dark and light soy sauces of different brands and investigated their abilities to inhibit AGEs and whether their mechanism of action was pre- or post-Amadori or involved chelation of transition metals. The antioxidant capacities of soy sauces were compared using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) method and by measuring their total phenolic contents. Model proteins (lysozyme, albumin) were glycated using fructose with or without soy sauces with subsequent analysis of cross-linked AGEs by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The effect of soy sauces on pre- and post-Amadori inhibition of AGEs was investigated by measuring fructosamine and AGEs following reincubation of ribose-glycated (ribated) lysozyme, respectively. Dark soy sauces had higher antioxidant capacities and phenolic content and were more effective inhibitors of post-Amadori-derived cross-linked AGEs. However, light soy sauces were more effective at inhibiting fructosamine and had more potent metal chelation properties. This study reports the antiglycation properties of soy sauces, but further studies are required to determine the constituents responsible for this effect and whether soy sauce consumption can reduce oxidative stress and AGEs in diabetic subjects.

  10. Effects of different Fe levels from Fe-nano-chelate and Fe-EDDHA sources on growth and some nutrients concentrations in cowpea in a calcareous soil

    Directory of Open Access Journals (Sweden)

    L. Jokar

    2015-08-01

    Full Text Available To evaluate the effects of different levels of iron (Fe (from Fe-nano-chelate and Fe-EDDHA sources on growth parameters, concentration and absorption of Fe and some nutrients in cowpea (Vigna unguiculata in a calcareous soil, a greenhouse experiment was conducted based on completely randomized design with three replications. Treatments consisted of four levels of Fe (0, 0.135, 0.270 and 0.405 mg Fe per kg soil as Fe-nano-chelate or Fe-EDDHA. The studied soil (Fine-loamy, carbonatic, thermic, Typic Calcixerepts had a loam texture with low available Fe content. Results showed that application of both Fe fertilizers increased shoot dry-matter yield, root dry matter yield, number of pods per plant, weight of pods and seeds per plant, grain weight per pot, shoot Fe concentration and Fe uptake by cowpea as compared to control treatment. Some of the evaluated growth parameters at all levels of Fe from Fe-nano-chelate source were higher than the Fe-EDDHA source and some were the same and had no significant difference. Application of both Fe-nano-chelate and Fe-EDDHA decreased phosphorus and manganese concentrations in shoots as compared to control treatment. Concentration of zinc and cooper in shoots was not significantly affected by the Fe level. In conclusion, lower rates of Fe-nano-chelate were required, as compared to Fe-EDDHA, to alleviate iron deficiency in cowpea grown in calcareous soils.

  11. Investigation of metal–flavonoid chelates and the determination of flavonoids via metal–flavonoid complexing reactions

    Directory of Open Access Journals (Sweden)

    DUSAN MALESEV

    2007-10-01

    Full Text Available Flavonoids constitute a large group of polyphenolic phytochemicals with antioxidant properties which are overwhelmingly exerted through direct free radical scavenging. Flavonoids also exhibit antioxidant properties through chelating with transition metals, primarily Fe(II, Fe(III and Cu(II, which participate in reactions generating free radicals. Metal–flavonoid chelates are considerably more potent free radical scavengers than the parent flavonoids and play a prominent role in protecting from oxidative stress. To unravel the origin of their potent biological action extensive physico–chemical studies were undertaken to reveal the chemical structure, chelation sites, assess the impact of the metal/ligand ratio on the structure of the complexes and the capacity of flavonoids to bind metal ions. In spite of such extensive efforts, data on the composition, structure and complex-formation properties are incomplete and sometimes even contradictory. The aim of this paper is to give a personal account on the development of the field through a retrospective evaluation of our own research which covers approximately 40 complexes of flavonoids from different flavonoids subclasses (rutin, quercetin, 3-hydroxyflavone, morin and hesperidin with several metal ions or groups and suggest directions for future research. Special emphasis will be given to the site of the central ion, the composition of the complexes, the role of pH in complex formation, the stability of metal–flavonoid complexes and their potential application for analytical purposes.

  12. Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Dodi, Alain; Bouscarel, Maelle [Commissariat a l' energie atomique - C.E.A, Centre d' Etude de Cadarache, Laboratoire d' Analyses Radiochimiques et Chimiques, St Paul lez Durance (France)

    2008-07-01

    This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

  13. Simultaneous Determination of Chelating Agents by Ion-Suppression and Ion-Pair Chromatography in Wastewater

    International Nuclear Information System (INIS)

    This article describes two methods for analysing chelating agents found in nuclear waste. First, ion-suppression chromatography using an anion exchange stationary phase and mobile phase consisting of a nitric acid solution and pure water gradient. UV detection was performed at 330 nm after the reaction with a post-column reagent composed of iron nitrate in perchloric acid. Secondly, ion-pair chromatography with a mobile phase consisting of a mixture of nitric acid, tetra-butyl-ammonium hydrogeno-sulphate, tetra-butyl-ammonium hydroxide and iron chloride. A reversed-phase material was used as a stationary phase and detection was performed by direct measurement of the UV absorption at 260 nm. The quantification limits were lower for ion-pair chromatography than for ion-suppression chromatography. Both methods were easy to implement and allow a multi-element separation in less than 30 min with low detection limits. (authors)

  14. The Role of Iron in the Skin & Cutaneous Wound Healing

    Directory of Open Access Journals (Sweden)

    Josephine Anne Wright

    2014-07-01

    Full Text Available In this review article we discuss current knowledge about iron in the skin and the cutaneous wound healing process. Iron plays a key role in both oxidative stress and photo-induced skin damage. The main causes of oxidative stress in the skin include reactive oxygen species (ROS generated in the skin by ultraviolet (UVA 320-400 nm portion of the ultraviolet spectrum and biologically available iron. We also discuss the relationships between iron deficiency, anaemia and cutaneous wound healing. Studies looking at this fall into two distinct groups. Early studies investigated the effect of anaemia on wound healing using a variety of experimental methodology to establish anaemia or iron deficiency and focused on wound-strength rather than effect on macroscopic healing or re-epithelialisation. More recent animal studies have investigated novel treatments aimed at correcting the effects of systemic iron deficiency and localised iron overload. Iron overload is associated with local cutaneous iron deposition, which has numerous deleterious effects in chronic venous disease and hereditary haemochromatosis. Iron plays a key role in chronic ulceration and conditions such as Rheumatoid Arthritis (RA and Lupus Erythematosus are associated with both anaemia of chronic disease and dysregulation of local cutaneous iron haemostasis. Iron is a potential therapeutic target in the skin by application of topical iron chelators and novel pharmacological agents, and in delayed cutaneous wound healing by treatment of iron deficiency or underlying systemic inflammation.

  15. Ferrous Ion Chelating, Superoxide Anion Radical Scavenging and Tyrosinase Inhibitory Properties of Pure and Commercial Essential Oils of Anetrhum Graveolens

    Directory of Open Access Journals (Sweden)

    Sh Darvish Alipour Astaneh

    2013-04-01

    Full Text Available Introduction: Despite slight toxicities of essential oils, they are not under strict control in many countries. Anethum graveolens is widely consumed and its essential oils are at public reach. This study was designed to study essential oils of Anethum graveolens. Methods: The biological properties of pure and commercial essential oils of Anethum graveolens were investigated. In fact, Ferrous ion chelating activity, superoxide anion radical scavenging property, tyrosinase inhibition and total flavonoids of the oils were determined. Results: Chelating activity of 7.8 µg of EDTA was equivalent to 2 µg of the pure oil. The oils had superoxide anion radical scavenging activities which may be related to their total phenol and flavonoid contents. IC50 of ferrous ion chelating, antityrosiase and superoxide anion radical scavenging activities of pure and commercial oils were 1.3, 1.4, 1 and (171.6, 589, 132 µg respectively. Antityrosiase activity of 6.4 µg pure oil was equal to 1000 µg of the commercial oil. Conclusion: Anethum possesses antioxidative and free radical scavenging properties. This oil chelates ferrous ions and superoxide radicals. It is effective in formation of reactive toxic products. Anethum has good potentials regarding its applications in food and drug industries.

  16. Chelation therapy in intoxications with mercury, lead and copper

    DEFF Research Database (Denmark)

    Cao, yang; Skaug, Marit Aralt; Andersen, Ole;

    2015-01-01

    In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... or tetrathiomolybdate may be more suitable alternatives today. In copper-toxicity, a free radical scavenger might be recommended as adjuvant to the chelator therapy...

  17. Novel Terbium Chelate Doped Fluorescent Silica Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ning Qiaoyu; Meng Jianxin; Wang Haiming; Liu Yingliang; Man Shiqing

    2006-01-01

    Novel terbium chelate doped silica fluorescent nanoparticles were prepared and characterized.The preparation was carried out in water-in-oil (W/O) microemulsion containing monomer precursor (pAB-DTPAA-APTEOS), Triton X-100, n-hexanol, and cyclohexane by controlling copolymerization of tetraethyl orthosilicate and 3-aminopropyl-triethyloxysilane.The nanoparticles are spherical and uniform in size, about 30 nm in diameter, strongly fluorescent, and highly stable.The amino groups directly introduced to the surface of the nanoparticles using APTEOS during preparation made the surface modification and bioconjugation of the nanoparticles easier.The nanoparticles are expected as an efficient time-resolved luminescence biological label.

  18. Progress on Study of Luminescence of Rare Earth Organic Chelates

    Institute of Scientific and Technical Information of China (English)

    杨燕生; 安保礼; 龚孟濂; 史华红; 雷衡毅; 孟建新

    2002-01-01

    Based on the investigation of the luminescence of a series of rare earth organic chelates, some relationships between luminescence and the structure of the chelates were proposed: the intensity of sensitized luminescence of central lanthanide ions(Ln3+) in a rare earth organic chelate depends on (1)the suitability of the energy gap between the excited triplet energy level of the ligands and the lowest excited energy level of Ln3+ ions; (2)the rigidity and planarity of the structure of the chelate molecule; (3)the existence of a suitable secondary ligand which may increase rigidity and the stability of the chelate molecule; and (4) the existence of a suitable π-conjugated system in the chelate molecule. According to the above relationships, 25 novel organic ligands were designed and synthesized, and their lanthanide chelates were prepared. Investigation of the photoluminescence for the new chelates shows that some of the chelates are strongly luminescent, and are applied to fluoroimmunoassay for determination of human immunoglobulin(IgG), to preparation of fluorescent plastics, and to determination of growth hormone for plants. Two novel spectroscopy-probe techniques for structure of coordination compounds and biological molecules were proposed and developed based on vibronic spectroscopy of Tb3+ complexes and fluorescence of Ce3+.

  19. Plutonium-237: comparative uptake in chelated and non-chelated form by channel catfish (Ictalurus punctatus)

    International Nuclear Information System (INIS)

    Chelation can either enhance or reduce the uptake of ingested plutonium relative to PuOH (monomer) in channel catfish. Reduced uptake of 237Pu-fulvate is due either to the molecular weight of the complex or its stability in metabolic systems. Increased uptake of 237Pu-citrate is attributable to instability of the complex in metabolic systems. (author)

  20. AKTIVITAS ANTIOKSIDAN EKSTRAK DIKHLOROMETANA DAN AIR JAHE (Zingiber officinale Roscoe PADA ASAM LINOLEAT [Antioxidant Activity of Ginger (Zingiber officinale Roscoe Dichloromethane and Water Exctract on Linoleic Acid

    Directory of Open Access Journals (Sweden)

    Aisyah Tri Septiana 1

    2002-08-01

    Full Text Available Antioxidant activity of various ginger extracts are different. The aims of this work are to determine the antioxidant activity of ginger extracts on linoleic acid. The antioxidant activities were tested on linoleic acid supplemented with water and dichloromethane extract of ginger. The antioxidant activity was tested by measuring malonaldehide absorbance. Total phenol and iron content of the extracts were analyzed by spectrometry. This research showed that antioxidant activity of water and dichloromethane extract of ginger was stronger than a-tocopherol, and antioxidant activity of dichloromethane extract is stronger than water extract of ginger. Antioxidant activity of ginger extracts, seems to be correlated with the total phenol and iron contents

  1. In vitro antioxidant potential of methanol extract of the medicinal plant, Acacia caesia (L.) Willd

    Institute of Scientific and Technical Information of China (English)

    Thambiraj J; Paulsamy S

    2012-01-01

    Objective: The in vitro antioxidant capability of methanolic leaf extract of the medicinal plant,Acacia caesia (L.) Willd (Mimosaceae) was evaluated by different assaying. Methods: The in vitro antioxidant activity was evaluated for total antioxidant, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical scavenging and metal chelating activities. Ascorbic acid and butylated hydroxy toluene (BHT) were kept as standards. Results: IC50 values observed for DPPH, hydroxyl radical scavenging and metal chelating assays were 109, 177 and 295 μg/ml respectively. Conclusions: The results clearly indicate that the methanolic leaf extract of the study species is effective in scavenging free radicals and has the potential to be powerful antioxidant.

  2. Antioxidant activity of ethanolic extract of Penicillium chrysogenum and Penicillium fumiculosum

    Directory of Open Access Journals (Sweden)

    Jakovljević Violeta D.

    2014-01-01

    Full Text Available The aim of this study was to investigate the biological and chemical activity on two species of fungi of the genus Penicillium isolated from wastewater. On the selected species of fungi the different antioxidant activity assays were carried out: DPPH free-radical scavenging activity, total antioxidant activity, Fe2+- chelating ability and Fe3+- reducing power. Total phenol content was also determinate for ethanolic extract of mycelia. Penicillium chrysogenum ethanolic extract contained higher total phenolic content and better total antioxidant capacity as well as ferrous ion chelating ability. Penicillium fumiculosum ethanolic extract showed higher DPPH free-radical scavenging activity, as well as reducing power. Based on the obtained results it can be concluded that two types of fungi are potential new sources of natural antioxidants. [Projekat Ministarstva nauke Republike Srbije, br. III 43004

  3. Sulfated polysaccharide fraction from marine algae Solieria filiformis: Structural characterization, gastroprotective and antioxidant effects.

    Science.gov (United States)

    Sousa, Willer M; Silva, Renan O; Bezerra, Francisco F; Bingana, Rudy D; Barros, Francisco Clark N; Costa, Luís E C; Sombra, Venicios G; Soares, Pedro M G; Feitosa, Judith P A; de Paula, Regina C M; Souza, Marcellus H L P; Barbosa, André Luiz R; Freitas, Ana Lúcia P

    2016-11-01

    A sulfated polysaccharide (SFP) fraction from the marine alga Solieria filiformis was extracted and submitted to microanalysis, molar mass estimation and spectroscopic analysis. We evaluated its gastroprotective potential in vivo in an ethanol-induced gastric damage model and its in vitro antioxidant properties (DPPH, chelating ferrous ability and total antioxidant capacity). Its chemical composition revealed to be essentially an iota-carrageenan with a molar mass of 210.9kDa and high degree of substitution for sulfate groups (1.08). In vivo, SFP significantly (Plevels. SFP presented an IC50 of 1.77mg/mL in scavenging DPPH. The chelating ferrous ability was 38.98%, and the total antioxidant capacity was 2.01mg/mL. Thus, SFP prevents the development of ethanol-induced gastric damage by reducing oxidative stress in vivo and possesses relevant antioxidant activity in vitro. PMID:27516258

  4. Preparation by enzymolysis and bioactivity of iron complex of fish protein hydrolysate (Fe-FPH)from low value fish

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Preparation of Fe2+ chelate of fish protein hydrolysate (Fe-FPH) obtained from low value fish proteins was introduced and its bioactivity was studied by compound enzymolysis. The optimum conditions for hydrolysate chelating Fe2+ are DH (degree of hydrolysis) at 5%, pH 7.0, 20°C and 15 min chelating time for FM (material not being defatted). Four types of Fe-FPH including CA (deposit after chelating), CB (deposit in 50% of absolute ethanol solution), CC (suspended deposit in 80% of absolute ethanol solution), and CD (bottom deposit in 80% of absolute ethanol solution) were fractionated with absolute ethanol from FM. Structural analysis through infra-red spectrum revealed that Fe2+ was combined strongly with amino-group and carboxyl-group in each chelate and each Fe2+ could form two five-member ring structures. All of the four chelates were shown more significant antioxidative activity and can be used as natural hydrophobic and hydrophilic antioxidant. Among all the chelates, the CB possesses the most effective antioxidative activity at 92% as high as that of a-tocopherol. Among all Fe-FPHs, only CD showed the most effective antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi, and Bacillus subtilis and can be used as natural antibacterial. It provides a more effective way for utilization of low value fish proteins and key information of Fe-FPH as additive in food industry.

  5. Cationic albumin-conjugated chelating agent as a novel brain drug delivery system in neurodegeneration.

    Science.gov (United States)

    Kamalinia, Golnaz; Khodagholi, Fariba; Shaerzadeh, Fatemeh; Tavssolian, Faranak; Chaharband, Farkhondeh; Atyabi, Fatemeh; Sharifzadeh, Mohammad; Amini, Mohsen; Dinarvand, Rassoul

    2015-11-01

    The critical role of metal ions and in particular iron in oxidative stress and protein aggregation offers chelation therapy as a sensible pharmaceutical strategy in oxidative stress-induced neuronal damages. In this research, we conjugated an iron-chelating agent, deferasirox, to cationized human serum albumin molecules in order to develop a novel brain delivery system for the management of neurodegenerative disorders due to the significant role of oxidative stress-induced neuronal injury in such diseases. Cationized albumin is known to be able to transport to brain tissue via adsorptive-mediated transcytosis. The developed structures were molecularly characterized, and their conjugation ratio was determined. PC12 cell line was utilized to evaluate the neuroprotective features of these newly developed molecules in the presence of hydrogen peroxide neuronal damage and to identify the mechanisms behind the observed neuronal protection including apoptotic and autophagic pathways. Furthermore, a rat model of Alzheimer's disease was utilized to evaluate the impact of conjugated structures in vivo. Data analysis revealed that the conjugated species were able to hinder apoptotic cell death while enhancing autophagic process. The developed conjugated species were also able to attenuate amyloid beta-induced learning deficits when administered peripherally.

  6. Native iron

    DEFF Research Database (Denmark)

    Brooks, Charles Kent

    2015-01-01

    , a situation unique in the Solar System. In such a world, iron metal is unstable and, as we all know, oxidizes to the ferric iron compounds we call 'rust'. If we require iron metal it must be produced at high temperatures by reacting iron ore, usually a mixture of ferrous (Fe2+) and ferric (Fe3+) oxides (Fe2O3......, hematite, or FeO.Fe2O3, magnetite), with carbon in the form of coke. This is carried out in a blast furnace. Although the Earth's core consists of metallic iron, which may also be present in parts of the mantle, this is inaccessible to us, so we must make our own. In West Greenland, however, some almost...... unique examples of iron metal, otherwise called 'native iron' or 'telluric iron', occur naturally....

  7. Potential Anticancer Properties of Grape Antioxidants

    Directory of Open Access Journals (Sweden)

    Kequan Zhou

    2012-01-01

    Full Text Available Dietary intake of foods rich in antioxidant properties is suggested to be cancer protective. Foods rich in antioxidant properties include grape (Vitis vinifera, one of the world’s largest fruit crops and most commonly consumed fruits in the world. The composition and cancer-protective effects of major phenolic antioxidants in grape skin and seed extracts are discussed in this review. Grape skin and seed extracts exert strong free radical scavenging and chelating activities and inhibit lipid oxidation in various food and cell models in vitro. The use of grape antioxidants are promising against a broad range of cancer cells by targeting epidermal growth factor receptor (EGFR and its downstream pathways, inhibiting over-expression of COX-2 and prostaglandin E2 receptors, or modifying estrogen receptor pathways, resulting in cell cycle arrest and apoptosis. Interestingly, some of these activities were also demonstrated in animal models. However, in vivo studies have demonstrated inconsistent antioxidant efficacy. Nonetheless, a growing body of evidence from human clinical trials has demonstrated that consumption of grape, wine and grape juice exerts many health-promoting and possible anti-cancer effects. Thus, grape skin and seed extracts have great potential in cancer prevention and further investigation into this exciting field is warranted.

  8. Chemical treatment of chelated metal finishing wastes.

    Science.gov (United States)

    McFarland, Michael J; Glarborg, Christen; Ross, Mark A

    2012-12-01

    This study evaluated two chemical approaches for treatment of commingled cadmium-cyanide (Cd-CN) and zinc-nickel (Zn-Ni) wastewaters. The first approach, which involved application of sodium hypochlorite (NaOCl), focused on elimination of chelating substances. The second approach evaluated the use of sodium dimethyldithiocarbamate (DMDTC) to specifically target and precipitate regulated heavy metals. Results demonstrated that by maintaining a pH of 10.0 and an oxidation-reduction potential (ORP) value of +600 mV, NaOCl treatment was effective in eliminating all chelating substances. Cadmium, chromium, nickel, and zinc solution concentrations were reduced from 0.27, 4.44, 0.06, and 0.10 ppm to 0.16, 0.17, 0.03, and 0.06 ppm, respectively. Similarly, a 1% DMDTC solution reduced these same metal concentrations in commingled wastewater to 0.009, 1.142, 0.036, and 0.320 ppm. Increasing the DMDTC concentration to 2% improved the removal of all regulated heavy metals except zinc, the removal of which at high pH values is limited by its amphotericity. PMID:23342939

  9. Effect of water cooking on antioxidant capacity of carotenoid-rich vegetables in Taiwan

    OpenAIRE

    Fuh-Juin Kao; Yu-Shan Chiu; Wen-Dee Chiang

    2014-01-01

    Carotenoid-rich green leafy vegetables including cilantro, Thai basil leaves, sweet potato leaves, and choy sum were selected to evaluate the effects of water cooking or boiling on their total carotenoid content (TCC), total phenolic content (TPC), and total antioxidant capacity (TAC). The percentage inhibition of peroxidation (%IP), Trolox equivalent antioxidant capacity (TEAC), and metal-chelating effect were used to evaluate TAC. The results indicated that TCC reached the maximum after boi...

  10. In Vitro Antioxidant and Anticancer Activity Studies on Drosera Indica L. (Droseraceae)

    OpenAIRE

    Raju Asirvatham; Arockiasamy Josphin Maria Christina; Anita Murali

    2013-01-01

    Purpose: The aim of present in vitro studies was performed to examine the antioxidant and anticancer activities of ethanol and aqueous extracts of Drosera indica L. Methods: Different concentrations (5 – 640mcg/ml) of the ethanol (EEDI) and aqueous (AEDI) extracts of D.indica L were used in various antioxidant assay methods such as hydroxyl radicals, DPPH, super oxide radical scavenging activity, chelating ability of ferrous ion, nitric oxide radical inhibition, ABTS and reducing power. Ascor...

  11. Sugars increase non-heme iron bioavailability in human epithelial intestinal and liver cells.

    Directory of Open Access Journals (Sweden)

    Tatiana Christides

    Full Text Available Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55 increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.

  12. Iron Prochelator BSIH Protects Retinal Pigment Epithelial Cells against Cell Death Induced by Hydrogen Peroxide

    OpenAIRE

    Charkoudian, Louise K.; Dentchev, Tzvete; Lukinova, Nina; Wolkow, Natalie; Dunaief, Joshua L.; Franz, Katherine J.

    2008-01-01

    Dysregulation of localized iron homeostasis is implicated in several degenerative diseases, including Parkinson’s, Alzheimer’s, and age-related macular degeneration, wherein iron-mediated oxidative stress is hypothesized to contribute to cell death. Inhibiting toxic iron without altering normal metal-dependent processes presents significant challenges for standard small molecule chelating agents. We previously introduced BSIH (isonicotinic acid [2-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl...

  13. The heme–p53 interaction: Linking iron metabolism to p53 signaling and tumorigenesis

    OpenAIRE

    Shen, Jia; Sheng, Xiangpeng; Chang, ZeNan; Wu, Qian; Xie, Dong; Wang, Fudi; HU, Ronggui

    2014-01-01

    Recently, we reported that heme binds to tumor suppressor p53 protein (TP53, best known as p53) and promotes its nuclear export and cytosolic degradation, whereas iron chelation stabilizes p53 protein and suppresses tumors in a p53-dependent manner. This not only provides mechanistic insights into tumorigenesis associated with iron excess, but also helps guide the administration of chemotherapy based on iron deprivation in the clinic.

  14. The experimental study on protective effects and mechanisms of chelating agents of catechols amino carboxylic acid for radiation injury induced by actimides(Th-234)

    International Nuclear Information System (INIS)

    The decorporative efficacy and antioxidative action of prompt and delayed consecutive administration of catecholicpolyaminopolycarboxylate ligands, 7601 and 9501 for radiothorium in mice were investigated. DTPA and Vitamin E were used as positive controls. The competitive abilities of 7601 and 9501 to mobilize the thorium with BSA were studied. Their inhibition effects on superoxide anionas radicals were measured with electron spin resonance. The results showed that 7601 and 9501 are able to effectively prevent the internal radiation injury induced radiothorium, attributing to their double functions of pronounced removal effectiveness and antioxidative action. Their protective effects were better than DTPA and Vitamin E. The mechanisms of protective effects of 7601 and 9501 for internal radiation injury was close related to competitive ability of chelating agent to chelate the thorium with BSA and oxygen free radical scavenging activities

  15. Comparison of Antioxidant Activities of Melanin Fractions from Chestnut Shell

    Directory of Open Access Journals (Sweden)

    Zeng-Yu Yao

    2016-04-01

    Full Text Available Chestnut shell melanin can be used as a colorant and antioxidant, and fractionated into three fractions (Fr. 1, Fr. 2, and Fr. 3 with different physicochemical properties. Antioxidant activities of the fractions were comparatively evaluated for the first time. The fractions exhibited different antioxidative potential in different evaluation systems. Fr. 1, which is only soluble in alkaline water, had the strongest peroxidation inhibition and superoxide anion scavenging activity; Fr. 2, which is soluble in alkaline water and hydrophilic organic solvents but insoluble in neutral and acidic water, had the greatest power to chelate ferrous ions; and Fr. 3, which is soluble both in hydrophilic organic solvents and in water at any pH conditions, had the greatest hydroxyl (·OH and 1,1-diphenyl-2-picryl-hydrazyl (DPPH· radicals scavenging abilities, reducing power, and phenolic content. The pigment fractions were superior to butylated hydroxytolune (BHT in ·OH and DPPH· scavenging and to ethylene diamine tetraacetic acid (EDTA in the Fe2+–chelation. They were inferior to BHT in peroxidation inhibition and O2·− scavenging and reducing power. However, BHT is a synthetic antioxidant and cannot play the colorant role. The melanin fractions might be used as effective biological antioxidant colorants.

  16. Spectroscopic studies on the antioxidant activity of ellagic acid

    Science.gov (United States)

    Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

    2014-09-01

    Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

  17. Iron in haemoglobinopathies and rare anaemias

    Directory of Open Access Journals (Sweden)

    John Porter

    2014-12-01

    Full Text Available Iron overload in haemoglobinopathies and rare anaemias may develop from increased iron absorption secondary to hepcidin suppression, and/or from repeated blood transfusions. While the accumulation of body iron load from blood transfusion is inevitable and predictable from the variable rates of transfusion in the different conditions, there are some important differences in the distribution of iron overload and its consequences between these. Transfusion-dependent thalassaemia (TDT is the best described condition in which transfusional overload occurs. Initially iron loads into macrophages, subsquently hepatocytes, and then the endocrine system including the anterior pituiatry and finally the myocardium. The propensity to extrahepatic iron spread increases with rapid transfusion and with inadequate chelation therapy but there is considerable interpatient and interpopulation variability in this tendency. The conduits though which iron is delivered to tissues is through non transferrin iron species (NTBI which are taken into liver, endocrine tissues and myocardium through L-type calcium channells and possibly through other channells. Recent work by the MSCIO group1 suggests that levels of NTBI are determined by three mechanisms: i increasing with iron overload; ii increasing with ineffective erythropoieis; iii and decreasing when level of transferrin iron utilisation is high. In TDT all three mechanisms increase NTBI levels because transferrin iron utilisation is suppressed by hypertransfusion. It is hypothesized that the transfusion regimen and target mean Hb may have a key impact on NTBI levels because high transfusion regimes may suppress the ‘sink’ effect of the erythron though decreased clearance of transferrin iron. In sickle cell disease (SCD without blood transfusion the anaemia results mainly from haemolysis rather than from ineffective erythropoiesis.2 Thus there is a tendency to iron depletion because of urinary iron loss from

  18. Role of phenolics as antioxidants, biomolecule protectors and as anti-diabetic factors - Evaluation on bark and empty pods of Acacia auriculiformis

    Institute of Scientific and Technical Information of China (English)

    Arumugam Sathya; Perumal Siddhuraju

    2012-01-01

    Objective:To search for an efficient and inexpensive source of phytoconstituents with antioxidant potential and health promoting traits from bark and empty pods of Acacia auriculiformis (A. auriculiformis). Methods: Samples of bark and empty pod extracts were analyzed for bioactives (phenolics, flavonoids and proanthocyanidins) and subjected to free radical scavenging activity on DPPH˙, ABTS˙+, OH˙, O2•-and NO along with the determination of reducing power, iron chelating activity and peroxidation inhibition. Defensive action of extracts on biomolecules and cell membranes were evaluated by DNA nicking assay and haemolysis inhibition assay respectively.α-amylase andα-glucosidase inhibitory potentials were also determined. Results: All the bioactives analyzed were higher in bark (B) than empty pods (EP) [TPC: B (574.51±16.11); EP (96.80±3.45) mg GAE/g. TFC: B (94.71±7.65); EP (247.87±20.45) mg RE/g. Proanthocyanidins: B (2.81±0.31); EP (1.25±0.01) mg LE/100 g DM] except flavonoids. Both the extracts showed higher quenching capacity on DPPH and ABTS (DPPH:B (0.21±0.01);EP (1.51±0.17) g extract/g DPPH. ABTS:B (111 519.14±79 340.91);EP (80 232.55±32 894.12) mmol TE/g) with the FRAP of B (84 515.63±3 350.69) and EP (47 940.79±1 257.60) mmol Fe (II)/g. Iron chelation was not observed. In addition, they showed lower quenching activity on OH˙(B (48.95±1.72);EP (34.94±1.62)%) and equivalent quenching on O2•-(B (53.47±3.92);EP (24.41±2.61)%), NO (B (49.04±5.04);EP (51.00±5.13)%), peroxidation inhibition (B (67.50±5.50); EP (55.1±2.3)%) and antihaemolytic potential (B (87.60±6.84)%) towards authentic antioxidant standards. Interestingly, Empty pod extracts are devoid of antihaemolytic activity. Both the extracts showed dose dependent DNA protection. Besides this, bark and empty pod extracts exhibited dual inhibiting potential againstα-amylase andα-glucosidase enzymes. Conclusions: On summarization, it insinuated that both bark and empty pods

  19. Is copper chelation an effective anti-angiogenic strategy for cancer treatment?

    Science.gov (United States)

    Antoniades, V; Sioga, A; Dietrich, E M; Meditskou, S; Ekonomou, L; Antoniades, K

    2013-12-01

    Angiogenesis and the acquisition of an angiogenic phenotype is important for cancer cell proliferation. Copper in an essential trace element that participates in many enzymatic complexes like the cytochrome c, superoxide dismutase and lysyl oxidase and it is involved in processes, like embryogenesis, growth, angiogenesis and carcinogenesis. In particular, its involvement in carcinogenesis was described for the first time in oral submucous fibrosis, where fibroblasts produce large amounts of collagen in the presence of copper. Copper's action in carcinogenesis is two-fold: (1) it participates in reactions with an increased redox potential that result in the production of oxidative products and oxidative stress. Through this mechanism, copper may cause DNA mutations in the nucleus and mitochondria or alterations to membrane phospholipids, (2) it participates in angiogenesis even in the absence of angiogenic molecules, as it was reported for the first time in rabbit cornea models with copolymer pellets charged with PGE1. Copper chelation regimens like penicillamine and tetrathiomolybdate are being described in the literature as having anti-angiogenic, anti-fibrotic and anti-inflammatory actions. Animal models of brain cancer that evaluated the anti-angiogenic properties of copper, have proven evidence of the reduction of tumor's microvascular supply, tumor volume and vascular permeability after plasma copper levels reduction. Interestingly, plasma copper levels reduction was shown to suppress micrometastases generation in mice models of breast cancer. We hypothesize that copper chelation therapy: increases oxidative stress in cancer cells to a level that does not allow survival because of the reduction of anti-oxidative enzymes production. It may also result in inhibition of angiogenesis and of the initiation of the angiogenic switch, because copper normally enhances endothelial cell migration and proliferation, improves binding of growth factors to endothelial cells

  20. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and lysi

  1. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    Science.gov (United States)

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  2. Macrocyclic Chelator Assembled RGD Multimers for Tumor Targeting

    OpenAIRE

    Zhang, Xiaofen; Liu, Hongguang; Miao, Zheng; Kimura, Richard; Fan, Feiyue; Cheng, Zhen

    2011-01-01

    Macrocyclic chelators have been extensively used for complexation of metal ions. A widely used chelator, DOTA, has been explored as a molecular platform to assemble multiple bioactive peptides in this paper. The multivalent DOTA-peptide bioconjugates demonstrate promising tumor targeting ability.

  3. Inapplicability of high pressure spray injection for chelate administration

    International Nuclear Information System (INIS)

    A high-pressure spray injector was tested for use in injecting chelating agents around radionuclides in wounds. It was difficult to employ because of the force required for proper injection, and it did not improve the effectiveness of the injected chelate in removing intramuscularly injected 238Pu. (U.S.)

  4. Adsorptive separation of rare earths by using chelating chitosan

    International Nuclear Information System (INIS)

    Two kinds of chelating chitosan were prepared by chemically modifying chitosan with functional groups of EDTA or DTPA, abbreviated as EDTA- and DTPA-chitosan hereafter, respectively, to investigate the adsorption behaviour for rare earths the mutual separation of which is the most difficult among metal ions on these chelating chitosan from dilute hydrochloric or sulfuric acid solution. The plots of the distribution ratio of a series of rare earths against equilibrium pH lay on different straight lines with slope of 3 corresponding to each earth for both of two chelating chitosan, suggesting that 3 hydrogen ions are released for the adsorption of unit ion of each rare earth by chelate formation with the functional group of EDTA or DTPA and that mutual adsorptive separation between adjacent rare earth is possible with these chelating chitosan. Apparent equilibrium constants of the adsorption were evaluated from the intercepts of these straight lines with the ordinate for each rare earth and for both chelating chitosan. It was found that the equilibrium constants of adsorption on EDTA- or DTPA-chitosan are quite analogous to those of chelate formation with EDTA or DTPA themselves, suggesting that chelating characteristics of these complexones is still maintained after their immobilization on polymer matrices of chitosan. (author)

  5. Antioxidative defense

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka

    2011-01-01

    Full Text Available Free radicals occur constantly during metabolism and take part in numerous physiological processes, such as: intra-cellular and inter-cellular signalization, gene expression, removal of damaged or senescent cells, and control of the tone of blood vessels. However, there is an increased quantity of free radicals in situations of so-called oxidative stress, when they cause serious damage to cellular membranes (peroxidation of their lipids, damage of membrane proteins, and similar, to interior cellular protein molecules, as well as DNA molecules and carbohydrates. This is precisely why the organism has developed numerous mechanisms for removing free radicals and/or preventing their production. Some of these are enzyme-related and include superoxide-dismutase, catalase, glutathione-peroxidase, and others. Other, non-enzyme mechanisms, imply antioxidative activities of vitamins E and C, provitamin A, coenzyme Q, reduced glutation, and others. Since free radicals can leave the cell that has produced them and become dispersed throughout the body, in addition to antioxidative defense that functions within cellular structures, antioxidant extra-cellular defense has also been developed. This is comprised by: transferrin, lactoferrin, haptoglobin, hemopexin, ceruloplasmin, albumins, extra-cellular isoform SOD, extracellular glutathione-peroxidase, glucose, bilirubin, urates, and many other molecules.

  6. Luminescence of a conjugated polymer containing europium (III) chelate

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Hao; Xie, Fang, E-mail: xiefang4498@126.com

    2013-12-15

    A europium (III) chelate has been incorporated in a conjugated polymer, poly-[2,2′-bipyridine-5,5′-diyl-(2,5-dihexyl-1,4-phenylene)]. From the absorbance and emission spectra measurement and using the Judd–Ofelt theory, an efficient energy transfer between the conjugated polymer and the europium (III) chelate has been confirmed. The luminescence lifetime of Eu{sup 3+} ion in the conjugated polymer is 0.352 ms and the emission cross section of this material is 3.11×10{sup −21} cm{sup 2}. -- Highlights: • A europium chelate has been incorporated in a conjugated polymer. • Energy transfer in the conjugated polymer containing europium chelate is efficient. • The conjugated polymer containing europium chelate is a promising optical material.

  7. Quantitative measurement of metal chelation by fourier transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Monika E. Miller

    2015-12-01

    Full Text Available Nutritionally important minerals are more readily absorbed by living systems when complexed with organic acids, resulting in higher consumer demand and premium prices for these products. These chelated metals are produced by reaction of metal oxides and acids in aqueous solution. However, unreacted dry blends are sometimes misrepresented as metal chelates, when in reality they are only simple mixtures of the reactants typically used to synthesize them. This practice has increased interest in developing analytical methods that are capable of measuring the extent of metal chelation for quality control and regulatory compliance. We describe a novel method to rapidly measure the percent chelation of citric and malic acids with calcium, magnesium, and zinc. Utilization of attenuated total reflectance (FTIR-ATR provides for the direct, rapid measurement of solid samples. The inclusion of an internal standard allows independent determination of either free or chelated acids from integrated areas in a single spectrum.

  8. Antioxidant Contents and Antioxidant Activities of White and Colored Potatoes (Solanum tuberosum L.)

    Science.gov (United States)

    Lee, Sang Hoon; Oh, Seung Hee; Hwang, In Guk; Kim, Hyun Young; Woo, Koan Sik; Woo, Shun Hee; Kim, Hong Sig; Lee, Junsoo; Jeong, Heon Sang

    2016-01-01

    This study was performed to evaluate and compare the antioxidant substance content and antioxidant activities of white (Superior) and colored (Hongyoung, Jayoung, Jasim, Seohong, and Jaseo) potatoes. The potatoes were extracted with 80% ethanol and were evaluated for the total polyphenol, flavonoid, and anthocyanin contents and for 1,1-diphenyl- 2-picrylhydrazyl (DPPH)/2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity, reducing power, and ferrous metal ion chelating effect. The total polyphenol, flavonoid, and anthocyanin contents of Hongyoung and Jayoung were higher than white and other colored potatoes. All colored potato extracts, except for Jaseo and Seohong, showed higher ABTS radical scavenging activities than the general white potato extract. Hongyoung and Jayoung had the highest ABTS and DPPH radical scavenging activities. Optical density values for the reducing power of Jayoung and Jaseo at concentration of 2 mg/mL were 0.148 and 0.090, respectively. All colored potato extracts had lower ferrous metal ion chelating effect than the white potato. A significant (Panthocyanin content (r=0.992), and ABTS radical scavenging activity (r=0.897). Based on these results, this research may be useful in developing the Hongyoung and Jayoung cultivars with high antioxidant activities. PMID:27390727

  9. Antioxidant Contents and Antioxidant Activities of White and Colored Potatoes (Solanum tuberosum L.).

    Science.gov (United States)

    Lee, Sang Hoon; Oh, Seung Hee; Hwang, In Guk; Kim, Hyun Young; Woo, Koan Sik; Woo, Shun Hee; Kim, Hong Sig; Lee, Junsoo; Jeong, Heon Sang

    2016-06-01

    This study was performed to evaluate and compare the antioxidant substance content and antioxidant activities of white (Superior) and colored (Hongyoung, Jayoung, Jasim, Seohong, and Jaseo) potatoes. The potatoes were extracted with 80% ethanol and were evaluated for the total polyphenol, flavonoid, and anthocyanin contents and for 1,1-diphenyl- 2-picrylhydrazyl (DPPH)/2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity, reducing power, and ferrous metal ion chelating effect. The total polyphenol, flavonoid, and anthocyanin contents of Hongyoung and Jayoung were higher than white and other colored potatoes. All colored potato extracts, except for Jaseo and Seohong, showed higher ABTS radical scavenging activities than the general white potato extract. Hongyoung and Jayoung had the highest ABTS and DPPH radical scavenging activities. Optical density values for the reducing power of Jayoung and Jaseo at concentration of 2 mg/mL were 0.148 and 0.090, respectively. All colored potato extracts had lower ferrous metal ion chelating effect than the white potato. A significant (P<0.05) positive correlation was observed between total polyphenol content and total flavonoid content (r=0.919), anthocyanin content (r=0.992), and ABTS radical scavenging activity (r=0.897). Based on these results, this research may be useful in developing the Hongyoung and Jayoung cultivars with high antioxidant activities. PMID:27390727

  10. Antioxidant activity of wild edible plants in the Black Sea Region of Turkey

    OpenAIRE

    Özen, Tevfik

    2010-01-01

    The antioxidative activity of the 80% ethanol extract obtained from eleven commonly consumed wild edible plants was determined according to the phosphomolybdenum method, reducing power, metal chelating, superoxide anion and free radical scavenging activity and compared to standard compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox. Total phenolic compounds, flavonoids, and anthocyanins in the extracts were also measured. Trachystemon orientalis, Vaccin...

  11. Methanobactin: a copper binding compound having antibiotic and antioxidant activity isolated from methanotrophic bacteria

    Science.gov (United States)

    DiSpirito, Alan A.; Zahn, James A.; Graham, David W.; Kim, Hyung J.; Alterman, Michail; Larive, Cynthia

    2007-04-03

    A means and method for treating bacterial infection, providing antioxidant activity, and chelating copper using a copper binding compound produced by methanotrophic bacteria is described. The compound, known as methanobactin, is the first of a new class of antibiotics having gram-positive activity. Methanobactin has been sequenced, and its structural formula determined.

  12. Coccoloba uvifera (L. (Polygonaceae Fruit: Phytochemical Screening and Potential Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Maira Rubi Segura Campos

    2015-01-01

    Full Text Available The flora of Latin America attracts gaining interest as it provides a plethora of still unexplored or underutilized fruits that can contribute to human well-being due to their nutritional value and their content of bioactive compounds. Antioxidant compounds are now of considerable interest due to their effect of preventing or delaying aging and their apparent involvement in prevention of numerous human diseases, including cancer, atherosclerosis, Alzheimer’s disease, inflammation, and rheumatoid arthritis. In this work, the fruit of Coccoloba uvifera (L. was investigated for their in vitro antioxidant capacity using two assays based on reactions with a relatively stable single reagent radical (Trolox equivalent antioxidant capacity, TEAC; and DPPH free radical scavenging assay, DPPH, two assays based on chelating of metallic cations, and one based on the reduction of oxidized species. The TEAC value on ABTS radical, DPPH scavenging activity, ion chelation, and reducing power were found to be 897.6 μM of Trolox/100 g of sample, 22.8% of DPPH free radical scavenging, 11.3% of Cu2+-chelating activity, 23.9% of Fe2+-chelating activity, and a Fe2+-reducing power of 0.76 mg/mL, respectively. The free radical scavenging and antioxidant characteristics of C. uvifera may be due to the presence of diverse phytochemicals in the fruit as anthocyanins, ascorbic acid, phenolic compounds, and flavonoids.

  13. Antiglycation and Antioxidant Properties of Momordica charantia

    Science.gov (United States)

    Aljohi, Ali; Matou-Nasri, Sabine; Ahmed, Nessar

    2016-01-01

    The accumulation of advanced glycation endproducts (AGEs) and oxidative stress underlie the pathogenesis of diabetic complications. In many developing countries, diabetes treatment is unaffordable, and plants such as bitter gourd (or bitter melon; Momordica charantia) are used as traditional remedies because they exhibit hypoglycaemic properties. This study compared the antiglycation and antioxidant properties of aqueous extracts of M. charantia pulp (MCP), flesh (MCF) and charantin in vitro. Lysozyme was mixed with methylglyoxal and 0–15 mg/ml of M. charantia extracts in a pH 7.4 buffer and incubated at 37°C for 3 days. Crosslinked AGEs were assessed using gel electrophoresis, and the carboxymethyllysine (CML) content was analyzed by enzyme-linked immunosorbent assays. The antioxidant activities of the extracts were evaluated using assays to assess DPPH (1,1-diphenyl-2-picryl-hydrazyl) and hydroxyl radical scavenging activities, metal-chelating activity and reducing power of the extracts. The phenolic, flavonol and flavonoid content of the extracts were also determined. All extracts inhibited the formation of crosslinked AGEs and CML in a dose-dependent manner, with MCF being the most potent. The antioxidant activity of MCF was higher than that of MCP, but MCP showed the highest metal-chelating activity. MCF had the highest phenolic and flavonoid contents, whereas MCP had the highest flavonol content. M. charantia has hypoglycaemic effects, but this study shows that M. charantia extracts are also capable of preventing AGE formation in vitro. This activity may be due to the antioxidant properties, particularly the total phenolic content of the extracts. Thus, the use of M. charantia deserves more attention, as it may not only reduce hyperglycaemia but also protect against the build-up of tissue AGEs and reduce oxidative stress in patients with diabetes. PMID:27513747

  14. Treating Lead Toxicity: Possibilities beyond Synthetic Chelation

    Directory of Open Access Journals (Sweden)

    Shambhavi Tannir

    2013-01-01

    Full Text Available Lead, a ubiquitous metal, is one of the most abundant elements present on earth. Its easy availability and cost effectiveness made it an extremely popular component in the industrial revolution. However, its hazardous health effects were not considered at the time. Over the last few decades, with the adverse effects of lead coming to the forefront, nations across the world have started to recognize and treat lead toxicity. The most reliable and used method until now has been chelation therapy. Recent research has suggested the use of natural products and sources to treat lead poisoning with minimal or no side effects. This review has tried to summarize a few of the natural products/sources being investigated by various groups.

  15. The Mycobacterium tuberculosis high-affinity iron importer, IrtA, contains an FAD-binding domain.

    Science.gov (United States)

    Ryndak, Michelle B; Wang, Shuishu; Smith, Issar; Rodriguez, G Marcela

    2010-02-01

    Iron is an essential nutrient not freely available to microorganisms infecting mammals. To overcome iron deficiency, bacteria have evolved various strategies including the synthesis and secretion of high-affinity iron chelators known as siderophores. The siderophores produced and secreted by Mycobacterium tuberculosis, exomycobactins, compete for iron with host iron-binding proteins and, together with the iron-regulated ABC transporter IrtAB, are required for the survival of M. tuberculosis in iron deficient conditions and for normal replication in macrophages and in mice. This study further characterizes the role of IrtAB in M. tuberculosis iron acquisition. Our results demonstrate a role for IrtAB in iron import and show that the amino terminus domain of IrtA is a flavin-adenine dinucleotide-binding domain essential for iron acquisition. These results suggest a model in which the amino terminus of IrtA functions to couple iron transport and assimilation.

  16. The mechanism of patulin's cytotoxicity and the antioxidant activity of indole tetramic acids

    Energy Technology Data Exchange (ETDEWEB)

    Riley, R.T.; Showker, J.L. (Toxicology and Mycotoxins Research Unit, U.S. Department of Agriculture/Agricultural Research Service, Athens, GA (USA))

    1991-06-01

    In LLC-PK1 cells exposed to patulin (50 microM), lipid peroxidation, abrupt calcium influx, extensive blebbing, and total LDH release appeared to be serially connected events with each representing a step in the loss of structural integrity of the plasma membrane. The aforementioned patulin-induced events were prevented by concurrent incubation with butylated hydroxytoluene, deferoxamine, and cyclopiazonic acid, a fungal metabolite. Patulin also caused depletion of nonprotein sulfhydryls, increased 86Rb+ efflux, dome collapse, and eventually the loss of cell viability. These events were not prevented by antioxidants, results consistent with the hypothesis that they were also serially connected but occurring parallel to those previously mentioned. The earliest events observed in patulin-treated cells were the decrease in nonprotein sulfhydryls and increase in 86Rb+ efflux (5 min) which occurred before statistically significant alterations in protein-bound sulfhydryls. The increased potassium efflux (86Rb+ efflux) occurred via a pathway distinct from BaCl2, quinine, or tetraethylammonium sensitive potassium channels. This is the first published report of the antioxidant activity of indole tetramic acids (cyclopiazonic acid and cyclopiazonic acid imine). The protective effect of tetramic acids in LLC-PK1 cells was restricted to indole tetramic acids, and their prevention of lipid peroxidation did not involve iron chelation. The results of this study demonstrate that cyclopiazonic acid is a potent inhibitor of azide-insensitive, ATP-dependent, a23187-sensitive calcium uptake by the lysate of LLC-PK1 cells. This result is consistent with the hypothesis that the endoplasmic reticulum calcium transport ATPase is a sensitive target for cyclopiazonic acid in LLC-PK1 cells.

  17. Relationship between conformational flexibility and chelate cooperativity.

    Science.gov (United States)

    Misuraca, M Cristina; Grecu, Tudor; Freixa, Zoraida; Garavini, Valentina; Hunter, Christopher A; van Leeuwen, Piet W N M; Segarra-Maset, M Dolores; Turega, Simon M

    2011-04-15

    A family of four biscarbamates (AA) and four bisphenols (DD) were synthesized, and H-bonding interactions between all AA•DD combinations were characterized using (1)H NMR titrations in carbon tetrachloride. A chemical double mutant cycle analysis shows that there are no secondary electrostatic interactions or allosteric cooperativity in these systems, and the system therefore provides an ideal platform for investigating the relationship between chemical structure and chelate cooperativity. Effective molarities (EMs) were measured for 12 different systems, where the number of rotors in the chains connecting the two H-bond sites was varied from 5 to 20. The association constants vary by less than an order of magnitude for all 12 complexes, and the variation in EM is remarkably small (0.1-0.9 M). The results provide a relationship between EM and the number of rotors in the connecting chains (r): EM ≈ 10r(-3/2). The value of 10 M is the upper limit for the value of EM for a noncovalent intramolecular interaction. Introduction of rotors reduces the value of EM from this maximum in accord with a random walk analysis of the encounter probability of the chain ends (r(-3/2)). Noncovalent EMs never reach the very high values observed for covalent processes, which places limitations on the magnitudes of the effects that one is likely to achieve through the use of chelate cooperativity in supramolecular assembly and catalysis. On the other hand, the decrease in EM due to the introduction of conformational flexibility is less dramatic than one might expect based on the behavior of covalent systems, which limits the losses in binding affinity caused by poor preorganization of the interaction sites.

  18. Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

    International Nuclear Information System (INIS)

    Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

  19. Genotoxic effect of ethacrynic acid and impact of antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Ward, William M.; Hoffman, Jared D.; Loo, George, E-mail: g_loo@uncg.edu

    2015-07-01

    It is known that ethacrynic acid (EA) decreases the intracellular levels of glutathione. Whether the anticipated oxidative stress affects the structural integrity of DNA is unknown. Therefore, DNA damage was assessed in EA-treated HCT116 cells, and the impact of several antioxidants was also determined. EA caused both concentration-dependent and time-dependent DNA damage that eventually resulted in cell death. Unexpectedly, the DNA damage caused by EA was intensified by either ascorbic acid or trolox. In contrast, EA-induced DNA damage was reduced by N-acetylcysteine and by the iron chelator, deferoxamine. In elucidating the DNA damage, it was determined that EA increased the production of reactive oxygen species, which was inhibited by N-acetylcysteine and deferoxamine but not by ascorbic acid and trolox. Also, EA decreased glutathione levels, which were inhibited by N-acetylcysteine. But, ascorbic acid, trolox, and deferoxamine neither inhibited nor enhanced the capacity of EA to decrease glutathione. Interestingly, the glutathione synthesis inhibitor, buthionine sulfoxime, lowered glutathione to a similar degree as EA, but no noticeable DNA damage was found. Nevertheless, buthionine sulfoxime potentiated the glutathione-lowering effect of EA and intensified the DNA damage caused by EA. Additionally, in examining redox-sensitive stress gene expression, it was found that EA increased HO-1, GADD153, and p21mRNA expression, in association with increased nuclear localization of Nrf-2 and p53 proteins. In contrast to ascorbic acid, trolox, and deferoxamine, N-acetylcysteine suppressed the EA-induced upregulation of GADD153, although not of HO-1. Overall, it is concluded that EA has genotoxic properties that can be amplified by certain antioxidants. - Highlights: • Ethacrynic acid (EA) caused cellular DNA damage. • EA-induced DNA damage was potentiated by ascorbic acid or trolox. • EA increased ROS production, not inhibited by ascorbic acid or trolox. • EA

  20. Antioxidant Capacity and the Correlation with Major Phenolic Compounds, Anthocyanin, and Tocopherol Content in Various Extracts from the Wild Edible Boletus edulis Mushroom

    OpenAIRE

    Emanuel Vamanu; Sultana Nita

    2013-01-01

    Boletus edulis is a wild edible mushroom habitually consumed by rural populations. Ethanolic and methanolic extracts was obtained in cold and hot water from dried fruit bodies. The antioxidant activity of freeze-dried extracts from B. edulis were investigated using free radicals scavenging activity, reducing power, metal chelating effect, inhibition of lipid peroxidation, and the identification of antioxidant compounds. The levels of different compounds with antioxidant properties were higher...

  1. Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells

    DEFF Research Database (Denmark)

    Nygaard, Sanne Bjørn; Larsen, Agnete; Knuhtsen, Astrid;

    2014-01-01

    BACKGROUND: Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron......-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS: Using INS-1E...... cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl...

  2. Abiotic reductive extraction of arsenic from contaminated soils enhanced by complexation: Arsenic extraction by reducing agents and combination of reducing and chelating agents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Jung [Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo 561-675 (Korea, Republic of); Lee, Jae-Cheol [Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo 561-675 (Korea, Republic of); Baek, Kitae, E-mail: kbaek@jbnu.ac.kr [Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo 561-675 (Korea, Republic of); Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo 561-675 (Korea, Republic of)

    2015-02-11

    Highlights: • Abiotic reductive extraction of As from contaminated soils was studied. • Oxalate/ascorbate were effective in extracting As bound to amorphous iron oxides. • Reducing agents were not effective in extracting As bound to crystalline oxides. • Reductive As extraction was greatly enhanced by complexation. • Combination of dithionite and EDTA could extract about 90% of the total As. - Abstract: Abiotic reductive extraction of arsenic from contaminated soils was studied with various reducing agents and combinations of reducing and chelating agents in order to remediate arsenic-contaminated soils. Oxalate and ascorbic acid were effective to extract arsenic from soil in which arsenic was associated with amorphous iron oxides, but they were not effective to extract arsenic from soils in which arsenic was bound to crystalline oxides or those in which arsenic was mainly present as a scorodite phase. An X-ray photoelectron spectroscopy study showed that iron oxides present in soils were transformed to Fe(II,III) or Fe(II) oxide forms such as magnetite (Fe{sub 3}O{sub 4}, Fe{sup II}Fe{sub 2}{sup III}O{sub 4}) by reduction with dithionite. Thus, arsenic extraction by dithionite was not effective due to the re-adsorption of arsenic to the newly formed iron oxide phase. Combination of chelating agents with reducing agents greatly improved arsenic extraction from soil samples. About 90% of the total arsenic could be extracted from all soil samples by using a combination of dithionite and EDTA. Chelating agents form strong complexation with iron, which can prevent precipitation of a new iron oxide phase and also enhance iron oxide dissolution via a non-reductive dissolution pathway.

  3. Polyphenolic content and antioxidant activity of some wild Saudi Arabian asteraceae plants

    Institute of Scientific and Technical Information of China (English)

    Abdelaaty A Shahat; Abeer Y Ibrahim; Mansour S Elsaid

    2014-01-01

    Objective:To study the antioxidant properties of crude extract of differentAsteraceae plants. Methods:The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities.Results:Picris cyanocarpa(P. cyanocarpa) andAnthemis deserti(A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima(A. fragrantissima) andArtemissia monosperma(A. monosperma) were the most efficient as ion chelator(100% at100,200 and400 μg/mL)A. fragrantissima and Rhantarium appoposum(R. appoposum) showed100% inhibition on peroxidation of linoleic acid emulsion at200 and400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed100 and95% inhibition percentage at400 μg/mL, respectively.Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. Conclusions:In most testsP. cyanocarpa andA. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger.

  4. Treating thalassemia major-related iron overload: the role of deferiprone

    Directory of Open Access Journals (Sweden)

    Berdoukas V

    2012-10-01

    Full Text Available Vasilios Berdoukas,1 Kallistheni Farmaki,2 Susan Carson,1 John Wood,3 Thomas Coates11Division of Hematology/Oncology, Children's Hospital Los Angeles, Los Angeles, CA, USA; 2Thalassemia Unit, General Hospital of Corinth, Corinth, Greece; 3Division of Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, USAAbstract: Over the last 20 years, management for thalassemia major has improved to the point where we predict that patients' life expectancy will approach that of the normal population. These outcomes result from safer blood transfusions, the availability of three iron chelators, new imaging techniques that allow specific organ assessment of the degree of iron overload, and improvement in the treatment of hepatitis. In October 2011, the Food and Drug Administration licensed deferiprone, further increasing the available choices for iron chelation in the US. The ability to prescribe any of the three chelators as well as their combinations has led to more effective reduction of total body iron. The ability to determine the amount of iron in the liver and heart by magnetic resonance imaging allows the prescription of the most appropriate chelation regime for patients and to reconsider what our aims with respect to total body iron should be. Recent evidence from Europe has shown that by normalizing iron stores not only are new morbidities prevented but also reversal of many complications such as cardiac failure, hypothyroidism, hypogonadism, impaired glucose tolerance, and type 2 diabetes can occur, improving survival and patients' quality of life. The most effective way to achieve normal iron stores seems to be with the combination of deferoxamine and deferiprone. Furthermore, outcomes should continue to improve in the future. Starting relative intensive chelation in younger children may prevent short stature and abnormal pubertal maturation as well as other iron-related morbidities. Also, further information should become available on the

  5. Neuroprotective Role of a Novel Copper Chelator against Aβ42 Induced Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar Singh

    2013-01-01

    Full Text Available Alzheimer's disease (AD is a progressive neurodegenerative disease and associated with the extracellular deposits of amyloid-β peptide in hippocampus region. Metal ions like Cu, Fe and Zn are known to associate with the amyloid beta (Aβ at high concentration and interaction of these ions with soluble and aggregated forms of Aβ peptide help in development of AD. Here we showed Cu mediated neurotoxicity in the eye tissues of transgenic Drosophila expressing human amyloid β and its rescue through a novel Cu chelator. In this context, we have synthesised and characterized the compound L 2,6-Pyridinedicarboxylic acid, 2,6-bis[2-[(4-carboxyphenyl methylene] hydrazide] by Mass spectra (MS and Elemental analysis (EA. The Cu chelation potential of the compound L is tested in vivo in Drosophila. Oral administration of Copper to the transgenic larvae resulted in severe degeneration in eye tissues, which was rescued by the supplementation of compound L. The levels of anti-oxidant markers like SOD and MDA were measured in compound L treated flies and found a significant rescue (P<0.001. Further rescue of the eye degeneration phenotypes as revealed by SEM affirm the role of copper in Aβ toxicity. Hence, use of compound L, an amidoamine derivative, could be a possible therapeutic measure for Aβ induced neurotoxicity.

  6. ATOX1 gene silencing increases susceptibility to anticancer therapy based on copper ionophores or chelating drugs.

    Science.gov (United States)

    Barresi, Vincenza; Spampinato, Giorgia; Musso, Nicolò; Trovato Salinaro, Angela; Rizzarelli, Enrico; Condorelli, Daniele Filippo

    2016-03-01

    Copper is a catalytic cofactor required for the normal function of many enzymes involved in fundamental biological processes but highly cytotoxic when in excess. Therefore its homeostasis and distribution is strictly regulated by a network of transporters and intracellular chaperones. ATOX1 (antioxidant protein 1) is a copper chaperone that plays a role in copper homeostasis by binding and transporting cytosolic copper to ATPase proteins in the trans-Golgi network. In the present study the Caco-2 cell line, a colon carcinoma cell line, was used as an in vitro model to evaluate if ATOX1 deficiency could affect sensitivity to experimentally induced copper dyshomeostasis. Silencing of ATOX1 increased toxicity of a short treatment with a high concentration of Cu(2+). Copper ionophores, such as 5-chloro-8-hydroxyquinoline, induced a copper-dependent cell toxicity which was significantly potentiated after ATOX1 silencing. The copper chelator TPEN (N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine) produced a form of cell toxicity that was reversed by the addition of Cu(2+). ATOX1 silencing increased Caco-2 cell sensitivity to TPEN toxicity. Our results suggest the possibility of a therapy with copper-chelating or ionophore drugs in subtypes of tumors showing specific alterations in ATOX1 expression. PMID:26784148

  7. Chelation therapy for metal intoxication: comments from a thermodynamic viewpoint.

    Science.gov (United States)

    Nurchi, Valeria Marina; Alonso, Miriam Crespo; Toso, Leonardo; Lachowicz, Joanna Izabela; Crisponi, Guido

    2013-10-01

    Chelation therapy plays a prominent role in the clinical treatment of metal intoxication. In this paper the principal causes of metal toxicity are exposed, and the chemical and biomedical requisites of a chelating agent are sketched. The chelating agents currently in use for scavenging toxic metal ions from humans belong to few categories: those characterized by coordinating mercapto groups, by oxygen groups, poliaminocarboxylic acids, and dithiocarbamates. Considering that the complex formation equilibria have been studied for less than 50% of chelators in use, some reflections on the utility of stability constants are presented, together with an evaluation of ligands under the stability profile. The competition between endogenous and toxic target metal ions for the same chelating agent is furthermore examined. A thorough examination of stability constant databases has allowed to select, for each toxic metal, the ligands distinguished by the best pMe values. Even though this selection does not consider the biomedical requisites of a chelating agent, it gives a clear picture both of the pMe values that can be attained, and of the most appropriate chelators for each metal ion. PMID:23895193

  8. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    Directory of Open Access Journals (Sweden)

    Margaret E. Sears

    2013-01-01

    Full Text Available Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease.

  9. Effect of tris(3-hydroxy-4-pyridinonate) iron(III) complexes on iron uptake and storage in soybean (Glycine max L.).

    Science.gov (United States)

    Santos, Carla S; Carvalho, Susana M P; Leite, Andreia; Moniz, Tânia; Roriz, Mariana; Rangel, António O S S; Rangel, Maria; Vasconcelos, Marta W

    2016-09-01

    Iron deficiency chlorosis (IDC) is a serious environmental problem affecting the growth of several crops in the world. The application of synthetic Fe(III) chelates is still one of the most common measures to correct IDC and the search for more effective Fe chelates remains an important issue. Herein, we propose a tris(3-hydroxy-4-pyridinonate) iron(III) complex, Fe(mpp)3, as an IDC corrector. Different morphological, biochemical and molecular parameters were assessed as a first step towards understanding its mode of action, compared with that of the commercial fertilizer FeEDDHA. Plants treated with the pyridinone iron(III) complexes were significantly greener and had increased biomass. The total Fe content was measured using ICP-OES and plants treated with pyridinone complexes accumulated about 50% more Fe than those treated with the commercial chelate. In particular, plants supplied with compound Fe(mpp)3 were able to translocate iron from the roots to the shoots and did not elicit the expression of the Fe-stress related genes FRO2 and IRT1. These results suggest that 3,4-HPO iron(III) chelates could be a potential new class of plant fertilizing agents.

  10. Minimal role of metallothionein in decreased chelator efficacy for cadmium.

    Science.gov (United States)

    Waalkes, M P; Watkins, J B; Klaassen, C D

    1983-05-01

    Chelator efficacy in Cd poisoning drops precipitously if therapy is not commenced almost immediately after exposure. Metallothionein (MT), a low-molecular-weight metal-binding protein with high affinity for Cd, may be important for this phenomenon. To more fully assess this role of MT in the acute drop in chelator efficacy following Cd poisoning, rats were injected iv with radioisotopic Cd (1mg/kg as CdCl2; 50 muCi/kg) followed by diethylenetriaminepentaacetic acid (DTPA; 90 mg/kg ip) at various times (0, 15, 30, 60, and 120 min) after Cd. Ther percentage of the Cd dose remaining in major organs 24 hr following Cd was determined. Although DTPA reduced Cd content in the various organs when given immediately after Cd, the chelator was ineffective at all later times. Increases in hepatic and renal MT did not occur until 2 hr after Cd, and did not coincide with the earlier drop in chelator efficacy. Blockade of MT synthesis by actinomycin D treatment (1.25 mg/kg, 1 hr before Cd) failed to prolong the chelators effectiveness. Furthermore, newborn rats have high levels of hepatic MT which had no effect on the time course of chelator effectiveness since DTPA still decreased Cd organ contents if given immediately following Cd but had no effect if given 2 hr after Cd. Therefore, if appears that MT does not have an important role in the acute decrease in efficacy of chelation therapy for Cd poisoning. The quick onset of chelator ineffectiveness may be due to the rapid uptake of Cd into tissues which makes it relatively unavailable of chelation.

  11. Prooxidant Mechanisms in Iron Overload Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Ching-Feng Cheng

    2013-01-01

    Full Text Available Iron overload cardiomyopathy (IOC, defined as the presence of systolic or diastolic cardiac dysfunction secondary to increased deposition of iron, is emerging as an important cause of heart failure due to the increased incidence of this disorder seen in thalassemic patients and in patients of primary hemochromatosis. At present, although palliative treatment by regular iron chelation was recommended; whereas IOC is still the major cause for mortality in patient with chronic heart failure induced by iron-overloading. Because iron is a prooxidant and the associated mechanism seen in iron-overload heart is still unclear; therefore, we intend to delineate the multiple signaling pathways involved in IOC. These pathways may include organelles such as calcium channels, mitochondria; paracrine effects from both macrophages and fibroblast, and novel mediators such as thromboxane A2 and adiponectin; with increased oxidative stress and inflammation found commonly in these signaling pathways. With further understanding on these complex and inter-related molecular mechanisms, we can propose potential therapeutic strategies to ameliorate the cardiac toxicity induced by iron-overloading.

  12. Chelation therapy for the management of diabetic complications: a hypothesis and a proposal for clinical laboratory assessment of metal ion homeostasis in plasma.

    Science.gov (United States)

    Frizzell, Norma; Baynes, John W

    2014-01-01

    In a recent article, we presented the hypothesis that decompartmentalized metal ions are a major contributor to the development of diabetic complications and supported the use of chelation therapy for the treatment of diabetic complications [Nagai R, Murray DB, Metz TO, Baynes JW. Chelation: a fundamental mechanism of action of AGE inhibitors, AGE breakers, and other inhibitors of diabetes complications. Diabetes 2012;61:549-59]. Evidence in support of this hypothesis included the observation that many drugs used in the treatment of diabetes are chelators, that advanced glycation end product (AGE) inhibitors and AGE breakers lack carbonyl-trapping or AGE-breaker activity but are potent chelators, and that simple copper chelators inhibit vascular pathology in diabetes and aging. In the present article, we extend this hypothesis, proposing the interplay between copper and iron in the development of pathology in diabetes and other chronic age-related diseases, including atherosclerosis and neurodegenerative diseases. We also discuss the need and provide a framework for the development of a clinical laboratory test to assess plasma autoxidative catalytic activity and transition metal homeostasis in vivo.

  13. Transgenic petunia with the iron(III-phytosiderophore transporter gene acquires tolerance to iron deficiency in alkaline environments.

    Directory of Open Access Journals (Sweden)

    Yoshiko Murata

    Full Text Available Iron is an essential nutrient for all plants. However, terrestrial plants often suffer from iron deficiency in alkaline soil due to its extremely low solubility. Alkaline soil accounts for about 30% of all cultivated ground in the world. Plants have evolved two distinct strategies, I and II, for iron uptake from the soil. Dicots and non-graminaceous monocots use Strategy I, which is primarily based on the reduction of iron(III to iron(II and the uptake of iron(II by the iron-regulated transporter, IRT1. In contrast, graminaceous plants use Strategy II to efficiently acquire insoluble iron(III. Strategy II comprises the synthesis and secretion of iron-chelating phytosiderophores, such as mugineic acids and the Yellow Stripe 1 transporter proteins of the iron(III-phytosiderophore complex. Barley, which exhibits the highest tolerance to iron deficiency in alkaline soil among graminaceous plants, utilizes mugineic acids and the specific iron(III-mugineic acids transporter, HvYS1. In this study, we established the transgenic plant Petunia hybrida, which originally had only Strategy I, by introducing the HvYS1 transporter gene derived from barley. When the transgenic plants were grown hydroponically in media containing the iron(III-2'-deoxymugineic acid complex, free 2'-deoxymugineic acid and its iron(III complex were detected in the root extract of the transgenic plant by electrospray ionization-Fourier transform-ion cyclotron resonance mass spectrometry. The growth of the transgenic petunia was significantly better than that of the control host in alkaline conditions. Consequently, the transgenic plant acquired a significantly enhanced tolerance to alkaline hydroponic media in the presence of the iron(III-2'-deoxymugineic acid complex. Furthermore, the flower color of the transgenic plant deepened. The results showed that iron-phytosiderophore complexes and their transporters can potentially be utilized to overcome the worldwide iron uptake problems

  14. Scavenging iron: a novel mechanism of plant immunity activation by microbial siderophores.

    Science.gov (United States)

    Aznar, Aude; Chen, Nicolas W G; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-04-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H₂O₂ staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  15. STUDY ON THERMAL DECOMPOSITION KINETICS OF URUSHIOL METAL CHELATE POLYMERS

    Institute of Scientific and Technical Information of China (English)

    HU Binghuan; CHEN Riyao; LIN Jinhuo; CHEN Wending

    1994-01-01

    The thermal decomposition kinetics of urushiol-Cu, urushiol-Nd and urushiol-Ti chelate polymers has been studied by non-isothermal thermogravimetry. The results suggest that the thermal decomposition kinetics of three chelate polymers are all of first order. Their average activation energy values of the thermal decomposition calculated by Ozawa-(Ⅰ) method are 110.79,136.98 and 163.64 kJ mol-1respectively,which increase linearly with the metal valence of the metal chelate polymers

  16. Siderophore-Mediated Iron Acquisition Influences Motility and Is Required for Full Virulence of the Xylem-Dwelling Bacterial Phytopathogen Pantoea stewartii subsp. stewartii

    OpenAIRE

    Burbank, Lindsey; Mohammadi, Mojtaba; Roper, M Caroline

    2014-01-01

    Iron is a key micronutrient for microbial growth but is often present in low concentrations or in biologically unavailable forms. Many microorganisms overcome this challenge by producing siderophores, which are ferric-iron chelating compounds that enable the solubilization and acquisition of iron in a bioactive form. Pantoea stewartii subsp. stewartii, the causal agent of Stewart's wilt of sweet corn, produces a siderophore under iron-limiting conditions. The proteins involved in the biosy...

  17. Mapping and characterization of iron compounds in Alzheimer's tissue

    International Nuclear Information System (INIS)

    Understanding the management of iron in the brain is of great importance in the study of neurodegeneration, where regional iron overload is frequently evident. A variety of approaches have been employed, from quantifying iron in various anatomical structures, to identifying genetic risk factors related to iron metabolism, and exploring chelation approaches to tackle iron overload in neurodegenerative disease. However, the ease with which iron can change valence state ensures that it is present in vivo in a wide variety of forms, both soluble and insoluble. Here, we review recent developments in approaches to locate and identify iron compounds in neurodegenerative tissue. In addition to complementary techniques that allow us to quantify and identify iron compounds using magnetometry, extraction, and electron microscopy, we are utilizing a powerful combined mapping/characterization approach with synchrotron X-rays. This has enabled the location and characterization of iron accumulations containing magnetite and ferritin in human Alzheimer's disease (AD) brain tissue sections in situ at micron-resolution. It is hoped that such approaches will contribute to our understanding of the role of unusual iron accumulations in disease pathogenesis, and optimise the potential to use brain iron as a clinical biomarker for early detection and diagnosis.

  18. The Investigation of Some Bioactive Compounds and Antioxidant Properties of Hawthorn (Crataegus monogyna subsp. monogyna jacq.

    Directory of Open Access Journals (Sweden)

    Serhat KESER

    2014-04-01

    Full Text Available The antioxidant and pharmacological effects of hawthorn have mainly been attributed to the polyphenolic contents. The aim of this research is to determine some bioactive compounds and antioxidant properties of hawthorn aqueous and ethanol extracts of leaves, flowers and ripened fruits. For this purpose, antioxidant activities of extracts were assessed on DPPH and #8226;, ABTS and #8226;+, superoxide scavenging, reducing power and ferrous metal chelating activity assays and phenolic content of extracts was determined by Folin-Cioacalteu and #8217;s reagent. The flavonoids including rutin, apigenin, myricetin, quercetin, naringenin and kaempferol, were identified by HPLC in the hawthorn extract. It was observed the aqueous and ethanol extracts of Crataegus monogyna subsp. monogyna fruits showed highest activity in reducing power and metal chelating activity assays. Additionally, it was determined that the aqueous flower extract showed higher flavonoid content than aqueous leaves extract. [J Intercult Ethnopharmacol 2014; 3(2.000: 51-55

  19. Interactions between Carotenoids from Marine Bacteria and Other Micronutrients: Impact on Stability and Antioxidant Activity.

    Science.gov (United States)

    Sy, Charlotte; Dangles, Olivier; Borel, Patrick; Caris-Veyrat, Catherine

    2015-11-19

    Recently isolated spore-forming pigmented marine bacteria Bacillus indicus HU36 are sources of oxygenated carotenoids with original structures (about fifteen distinct yellow and orange pigments with acylated d-glucosyl groups). In this study, we evaluated the stability (sensitivity to iron-induced autoxidation) and antioxidant activity (inhibition of iron-induced lipid peroxidation) of combinations of bacterial HU36 carotenoids with the bacterial vitamin menaquinone MQ-7 and with phenolic antioxidants (vitamin E, chlorogenic acid, rutin). Unexpectedly, MQ-7 strongly improves the ability of HU36 carotenoids to inhibit Fe(II)-induced lipid peroxidation, although MQ-7 was not consumed in the medium. We propose that their interaction modifies the carotenoid antioxidant mechanism(s), possibly by allowing carotenoids to scavenge the initiating radicals. For comparison, β-carotene and lycopene in combination were shown to exhibit a slightly higher stability toward iron-induced autoxidation, as well as an additive antioxidant activity as compared to the carotenoids, individually. HU36 carotenoids and phenolic antioxidants displayed synergistic activities in the inhibition of linoleic acid peroxidation induced by heme iron, but not by free iron. Synergism could arise from antioxidants interacting via electron transfer through the porphyrin nucleus of heme iron. Overall, combining antioxidants acting via complementary mechanisms could be the key for optimizing the activity of this bacterial carotenoid cocktail.

  20. Transferrin as a source of iron for Campylobacter rectus

    Directory of Open Access Journals (Sweden)

    Daniel Grenier

    2011-01-01

    Full Text Available Background and Objective: Campylobacter rectus is considered as one of the bacterial species of etiological importance in periodontitis. Iron-containing proteins such as transferrin are found in periodontal sites and may serve as a source of iron for periodontopathogens. The aim of this study was to investigate the capacity of C. rectus to assimilate transferrin-bound iron to support its growth. Design: Growth studies were performed in broth media pretreated with an iron-chelating resin and supplemented with various iron sources. The uptake of iron by C. rectus was monitored using 55Fe-transferrin. Transferrin-binding activity was assessed using a microplate assay while the degradation of transferrin and iron removal was evaluated by polyacrylamide gel electrophoresis. A colorimetric assay was used to determine ferric reductase activity. Results: Holotransferrin (iron-saturated form but not apotransferrin (iron-free form was found to support growth of C. rectus in an iron-restricted culture medium. Incubation of holotransferrin with cells of C. rectus resulted in removal of iron from the protein. A time dependent intracellular uptake of iron by C. rectus cells from 55Fe-transferrin was demonstrated. This uptake was significantly increased when bacteria were grown under an iron-limiting condition. Cells of C. rectus did not show transferrin-binding activity or proteolytic activity toward transferrin. However, a surface-associated ferric reductase activity was demonstrated. Conclusion: To survive and multiply in periodontal sites, periodontopathogens must possess efficient iron-scavenging mechanisms. In this study, we showed the capacity of C. rectus to assimilate iron from transferrin to support its growth. The uptake of iron appears to be dependent on a ferric reductive pathway.

  1. A Brief Review of Chelators for Radiolabeling Oligomers

    Directory of Open Access Journals (Sweden)

    Yuxia Liu

    2010-05-01

    Full Text Available The chemical modification of oligomers such as DNA, PNA, MORF, LNA to attach radionuclides for nuclear imaging and radiotherapy applications has become a field rich in innovation as older methods are improved and new methods are introduced. This review intends to provide a brief overview of several chelators currently in use for the labeling of oligomers with metallic radionuclides such as 99mTc, 111In and 188Re. While DNA and its analogs have been radiolabeled with important radionuclides of nonmetals such as 32P, 35S, 14C, 18F and 125I, the labeling methods for these isotopes involve covalent chemistry that is quite distinct from the coordinate-covalent chelation chemistry described herein. In this review, we provide a summary of the several chelators that have been covalently conjugated to oligomers for the purpose of radiolabeling with metallic radionuclides by chelation and including details on the conjugation, the choice of radionuclides and labeling methods.

  2. Effects of macromolecular chelators on intestinal cadmium absorption in mice

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, O.; Nielsen, J.B.; Bulman, R.A.

    1989-01-01

    Suppression of absorption by macromolecular chelators have been sucessful with several metals. In this paper a series of immobilized chelators ranging from DTPA to S-containing soft bases have been synthetized and investigated for ability to suppress intestinal uptake of /sup 109/Cd/sup 2+/ in mice. Dextran-O-ethyl-mercaptan, xanthates derived from polysaccharides and polyvinyl alcohol, dithiocarbamates of polyethylene imine and aminoethyl cellulose, and DTPA immobilized on aminopropyl silica were all ineffective. DTPA immobilized on aminoethyl cellulose even enhanced the intestinal uptake. The macromolecular chelators were without extensive effect on organ distribution of absorbed cadmium, except for dithiocarbamate immobilized on polyethylene imine, which enhanced the deposition of cadmium in several organs including the brain. Although the results are discouragign, they indicate that desing and synthesis of immobilized vicinal dithio compounds may represent an avenue for development of non-absorbable chelators with high affinity for cadmium.

  3. Mixed-chelate therapy of intratracheally deposited cadmium oxide

    International Nuclear Information System (INIS)

    Mixed-chelate treatment with EDTA and salicylic acid was no more effective in accelerating the removal of intratracheally instilled 109CdO, or in protecting against CdO-induced mortality, than was EDTA given alone

  4. Development of Multi-Functional Chelators Based on Sarcophagine Cages

    Directory of Open Access Journals (Sweden)

    Shuanglong Liu

    2014-04-01

    Full Text Available A new class of multifunctionalized sarcophagine derivatives was synthesized for 64Cu chelation. The platform developed in this study could have broad applications in 64Cu-radiopharmaceuticals.

  5. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    OpenAIRE

    Endo, Koji; Grubbs, Robert H.

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis.

  6. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    Science.gov (United States)

    Endo, Koji; Grubbs, Robert H.

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis. PMID:21563826

  7. Gradient ion-pair chromatographic method for the determination of iron N,N'-ethylenediamine-di-(2-hydroxy-5-sulfophenylacetate) by high performance liquid chromatography-atmospheric pressure ionization electrospray mass spectrometry.

    Science.gov (United States)

    García-Marco, Sonia; Cremonini, Mauro A; Esteban, Pedro; Yunta, Felipe; Hernández-Apaolaza, Lourdes; Placucci, Giuseppe; Lucena, Juan J

    2005-01-28

    The most effective remedy for iron deficiency is the use of synthetic iron chelates, specifically chelates derived from polyaminecarboxylic acids as EDDHSA (N,N'-ethylenediamine-di-(2-hidroxy-5-sulfophenylacetic) acid). A gradient ion-pair chromatographic method was developed to quantify the total amount of chelated iron in EDDHSA/Fe3+ fertilizers. Two mobile phases were used containing, respectively, 35 and 75% acetonitrile in a 0.005 M tetrabutylammonium hydroxide aqueous solution at pH 6.0. The stationary phase was a reverse phase C-18 column (150mm x 3.9mm i.d., dp = 5 microm). Two chromatographic peaks appeared and were identified by Electrospray Mass Spectrometry. The first peak corresponds to the monomer of EDDHSA/Fe3+ and the second peak has been assigned to condensation molecules. Quality parameters indicate that the method is suitable for the quantification of iron chelate by EDDHSA fertilizers. PMID:15729821

  8. Effects of Environmental Pollutants on Cellular Iron Homeostasis and Ultimate Links to Human Disease.

    Science.gov (United States)

    Schreinemachers, Dina M; Ghio, Andrew J

    2016-01-01

    Chronic disease has increased in the past several decades, and environmental pollutants have been implicated. The magnitude and variety of diseases may indicate the malfunctioning of some basic mechanisms underlying human health. Environmental pollutants demonstrate a capability to complex iron through electronegative functional groups containing oxygen, nitrogen, or sulfur. Cellular exposure to the chemical or its metabolite may cause a loss of requisite functional iron from intracellular sites. The cell is compelled to acquire further iron critical to its survival by activation of iron-responsive proteins and increasing iron import. Iron homeostasis in the exposed cells is altered due to a new equilibrium being established between iron-requiring cells and the inappropriate chelator (the pollutant or its catabolite). Following exposure to environmental pollutants, the perturbation of functional iron homeostasis may be the mechanism leading to adverse biological effects. Understanding the mechanism may lead to intervention methods for this major public health concern.

  9. Antioxidant properties and efficacies of synthesized alkyl caffeates, ferulates, and coumarates

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Durand, Erwann; Laguerre, Mickaël;

    2014-01-01

    /w microemulsion using the conjugated autoxidizable triene (CAT) assay. All evaluated phenolipids had radical scavenging, reducing power, and metal chelating properties. Only caffeic acid and caffeates were able to form a complex with iron via their catechol group in the phenolic ring. In the o/w emulsion...

  10. EFFECTS OF ENZYMATIC HYDROLYSIS ON THE ANTIOXIDANT ACTIVITY OF WATER- SOLUBLE ELASTIN EXTRACTED FROM BROILER AND SPENT HEN SKIN

    OpenAIRE

    Mehdi Nadalian; Salma Mohamad Yusop; Abdul Salam Babji; Wan Aida Wan Mustapha; Mohd Azri Azman

    2015-01-01

    Poultry by-products are great economic sources that need to be exploited. Poultry skin could be utilized to extract protein particularly elastin, which is often incorporated in the production of functional food, cosmetic industry or medicine due to its antioxidative properties. In this study, water-soluble elastin was successfully extracted from broiler and spent hen skin and analysed for antioxidant activities including DPPH (1,1-diphenyl-2-picryl hydrazyl), ABTS and metal chelating activity...

  11. Antioxidant Capacity and Phenolic Content of Caesalpinia pyramidalis Tul. and Sapium glandulosum (L.) Morong from Northeastern Brazil

    OpenAIRE

    Carlos Henrique Tabosa Pereira da Silva; Tadeu José da Silva Peixoto Sobrinho; Valérium Thijan Nobre de Almeida e Castro; Danielle da Cunha Amaral Lima; Elba Lúcia Cavalcanti de Amorim

    2011-01-01

    The aims of this study were to quantify the phenolic content and evaluate the antioxidant potential of extracts from the bark and leaves of C. pyramidalis and S. glandulosum. The total phenolic content (TPC) and total tannin content (TTC) were determined using the Folin-Ciocalteu method, and the total flavonoids content (TFC) was measured via complexation with aluminum chloride. The antioxidant activity was evaluated with DPPH (2.2-diphenyl-1-picrylhydrazyl) and FIC (ferrous ion chelating) as...

  12. Extraction of metals using supercritical fluid and chelate forming legand

    Science.gov (United States)

    Wai, Chien M.; Laintz, Kenneth E.

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  13. Extraction of metals using supercritical fluid and chelate forming ligand

    Science.gov (United States)

    Wai, C.M.; Laintz, K.E.

    1998-03-24

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

  14. Chemical composition and antioxidant activity of lichen Toninia candida

    Directory of Open Access Journals (Sweden)

    Nedeljko T. Manojlovic

    2012-04-01

    Full Text Available In the present investigation, methanol, chloroform and petrol ether extracts from the lichen Toninia candida (Weber Th. Fr, Catillariaceae, were assayed for their antioxidant activity. The phenolic composition of the extracts was determined by HPLC-UV analysis. The predominant phenolic compound in all the extracts was depsidone, norstictic acid. All the tested extracts of T. candida contain, besides norstictic acid, atranorin, stictic, protocetraric and usnic acid, but in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity and inhibitory activity towards lipid peroxidation. This is the first report of chemical composition and antioxidant antimicrobial activity of the lichen Toninia candida.

  15. The iron component of particulate matter is antiapoptotic: A clue to the development of lung cancer after exposure to atmospheric pollutants?

    Science.gov (United States)

    Lovera-Leroux, Melanie; Crobeddu, Belinda; Kassis, Nadim; Petit, Patrice X; Janel, Nathalie; Baeza-Squiban, Armelle; Andreau, Karine

    2015-11-01

    The classification of outdoor air pollution as carcinogenic for humans strengthens the increasing concern about particulate matter (PM). We previously demonstrated that PM exposure produces an antiapoptotic effect resulting from polycyclic aromatic hydrocarbons (PAH) and water-soluble components. In this study, we investigated transition metallic compounds, particularly iron, in order to decipher their underlying molecular mechanisms that prevent apoptosis. Human bronchial epithelial cells were exposed for 4 h to different PM samples with established antiapoptotic effect (e.g. PM-AW) or not (e.g. PM-VS) or to their metallic components (Fe, Mn, Zn and Al) before apoptosis induction by the calcium ionophore A23187 or Staurosporine. PM-AW, Fe, Mn and Al significantly reduced induced apoptosis. The antiapoptotic effect of Fe was enhanced by benzo(a)pyrene, a typical PAH compound, but was totally reversed by the iron chelator, deferiprone. Furthermore, particles and iron triggered cellular ROS generation and prevented the depletion in glutathione levels observed during A23187-induced apoptosis. In contrast to benzo(a)pyrene, PM-AW and Fe rapidly activated NRF2, subsequently upregulated several target genes (HO1, NQO1 and GPX1) and modulated some genes which control cell death (BCL2, BAX and p53). The key role of the NRF2 pathway in the antiapoptotic effect mediated by Fe and PM was demonstrated using siRNA technology. Our results suggest that the iron component participates in the antiapoptotic effect of PM by activating a NRF2-dependent antioxidant process. As resisting to cell death is one of the hallmarks of cancer cells, these findings provide additional clues for understanding the development of lung cancer after atmospheric pollution exposure. PMID:26419736

  16. Analysis of chemical composition and evaluation of antigenotoxic, cytotoxic and antioxidant activities of essential oil of Toddalia asiatica (L.) Lam.

    Institute of Scientific and Technical Information of China (English)

    Ramaraj Thirugnanasampandan; Rajarajeswaran Jayakumar; Murugaiyan Prabhakaran

    2012-01-01

    Objective: To analyse the chemical composition of essential oil isolated from the leaves ofToddalia asiatica (L.) Lam. and to test its bioactive properties. Methods: Gas chromatography-mass spectrometry (GC/MS) analysis and antigenotoxicity, cytotoxicity and antioxidant studies of isolated oil. Results: GC-MS analysis of oil revealed the presence of 42 compounds. The major compound in the oil was β-phellandrene (21.35%). DNA protecting activity of oil was considerably significant against H2O2 induced genotoxicity in human lymphocytes. Concentration of oil needed to protect 50% of DNA was calculated as 100 μg/mL. Cytotoxicity of oil against breast (MCF-7) and colorectal (HT-29) cancer cells were observed with the IC50 value of (7.80±0.03) μg/mL and (100.00±0.16) μg/mL respectively. Considerable DPPH free radical, hydroxyl radical scavenging, iron chelation and inhibition of lipid peroxidation activities of oil were also studied. Conclusions: The results of the present study clearly indicate oil could be a promising candidate for food and drug preparation.

  17. Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture.

    Science.gov (United States)

    Radzki, W; Gutierrez Mañero, F J; Algar, E; Lucas García, J A; García-Villaraco, A; Ramos Solano, B

    2013-09-01

    Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved tomato plants. For this purpose, siderophore production in MM9 medium by two selected bacterial strains was quantified, and the best was used for biological assay. Bacterial culture media free of bacteria (S) and with bacterial cells (BS), both supplemented with Fe were delivered to 12-week-old plants grown under iron starvation in hydroponic conditions; controls with full Hoagland solution, iron-free Hoagland solution and water were also conducted. Treatments were applied twice along the experiment, with a week in between. At harvest, plant yield, chlorophyll content and nutritional status in leaves were measured. Both the bacterial siderophore treatments significantly increased plant yield, chlorophyll and iron content over the positive controls with full Hoagland solution, indicating that siderophores are effective in providing Fe to the plant, either with or without the presence of bacteria. In summary, siderophores from strain Chryseobacterium C138 are effective in supplying Fe to iron-starved tomato plants by the roots, either with or without the presence of bacteria. Based on the amount of siderophores produced, an effective and economically feasible organic Fe chelator could be developed. PMID:23812968

  18. Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture.

    Science.gov (United States)

    Radzki, W; Gutierrez Mañero, F J; Algar, E; Lucas García, J A; García-Villaraco, A; Ramos Solano, B

    2013-09-01

    Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved tomato plants. For this purpose, siderophore production in MM9 medium by two selected bacterial strains was quantified, and the best was used for biological assay. Bacterial culture media free of bacteria (S) and with bacterial cells (BS), both supplemented with Fe were delivered to 12-week-old plants grown under iron starvation in hydroponic conditions; controls with full Hoagland solution, iron-free Hoagland solution and water were also conducted. Treatments were applied twice along the experiment, with a week in between. At harvest, plant yield, chlorophyll content and nutritional status in leaves were measured. Both the bacterial siderophore treatments significantly increased plant yield, chlorophyll and iron content over the positive controls with full Hoagland solution, indicating that siderophores are effective in providing Fe to the plant, either with or without the presence of bacteria. In summary, siderophores from strain Chryseobacterium C138 are effective in supplying Fe to iron-starved tomato plants by the roots, either with or without the presence of bacteria. Based on the amount of siderophores produced, an effective and economically feasible organic Fe chelator could be developed.

  19. Urinary iron excretion induced by intravenous infusion of deferoxamine in ß-thalassemia homozygous patients

    Directory of Open Access Journals (Sweden)

    Boturão-Neto E.

    2002-01-01

    Full Text Available The purpose of the present study was to identify noninvasive methods to evaluate the severity of iron overload in transfusion-dependent ß-thalassemia and the efficiency of intensive intravenous therapy as an additional tool for the treatment of iron-overloaded patients. Iron overload was evaluated for 26 ß-thalassemia homozygous patients, and 14 of them were submitted to intensive chelation therapy with high doses of intravenous deferoxamine (DF. Patients were classified into six groups of increasing clinical severity and were divided into compliant and non-compliant patients depending on their adherence to chronic chelation treatment. Several methods were used as indicators of iron overload. Total gain of transfusion iron, plasma ferritin, and urinary iron excretion in response to 20 to 60 mg/day subcutaneous DF for 8 to 12 h daily are useful to identify iron overload; however, urinary iron excretion in response to 9 g intravenous DF over 24 h and the increase of urinary iron excretion induced by high doses of the chelator are more reliable to identify different degrees of iron overload because of their correlation with the clinical grades of secondary hemochromatosis and the significant differences observed between the groups of compliant and non-compliant patients. Finally, the use of 3-9 g intravenous DF for 6-12 days led to a urinary iron excretion corresponding to 4.1 to 22.4% of the annual transfusion iron gain. Therefore, continuous intravenous DF at high doses may be an additional treatment for these patients, as a complement to the regular subcutaneous infusion at home, but requires individual planning and close monitoring of adverse reactions.

  20. THE STUDIES ON CHELATING FIBER V.ADSORPTION BEHAVIOR OF Au3+ ONTO CHELATING FIBER CONTAINING AMIDOXIME GROUPS

    Institute of Scientific and Technical Information of China (English)

    LINWeiping; LUYun; 等

    1992-01-01

    The adsorption behavior of ionic gold onto chelating fiber containing amidoxime groups was investigated. The chelating fiber presents high adsorption capacity for ionic gold Au3+(up to 626mg/g,when the content of amidoxime group reaches 7.59mmol/g),and possesses the ability to reduce the Au3+ into metallic gold,In the redox process,the amidoxime group is oxidized into carboxyl group.

  1. Design, selection, and characterization of thioflavin-based intercalation compounds with metal chelating properties for application in Alzheimer's disease.

    Science.gov (United States)

    Rodríguez-Rodríguez, Cristina; Sánchez de Groot, Natalia; Rimola, Albert; Alvarez-Larena, Angel; Lloveras, Vega; Vidal-Gancedo, José; Ventura, Salvador; Vendrell, Josep; Sodupe, Mariona; González-Duarte, Pilar

    2009-02-01

    Metal chelation is considered a rational therapeutic approach for interdicting Alzheimer's amyloid pathogenesis. At present, enhancing the targeting and efficacy of metal-ion chelating agents through ligand design is a main strategy in the development of the next generation of metal chelators. Inspired by the traditional dye Thioflavin-T, we have designed new multifunctional molecules that contain both amyloid binding and metal chelating properties. In silico techniques have enabled us to identify commercial compounds that enclose the designed molecular framework (M1), include potential antioxidant properties, facilitate the formation of iodine-labeled derivatives, and can be permeable through the blood-brain barrier. Iodination reactions of the selected compounds, 2-(2-hydroxyphenyl)benzoxazole (HBX), 2-(2-hydroxyphenyl)benzothiazole (HBT), and 2-(2-aminophenyl)-1H-benzimidazole (BM), have led to the corresponding iodinated derivatives HBXI, HBTI, and BMI, which have been characterized by X-ray diffraction. The chelating properties of the latter compounds toward Cu(II) and Zn(II) have been examined in the solid phase and in solution. The acidity constants of HBXI, HBTI, and BMI and the formation constants of the corresponding ML and ML2 complexes [M = Cu(II), Zn(II)] have been determined by UV-vis pH titrations. The calculated values for the overall formation constants for the ML2 complexes indicate the suitability of the HBXI, HBTI, and BMI ligands for sequestering Cu(II) and Zn(II) metal ions present in freshly prepared solutions of beta-amyloid (Abeta) peptide. This was confirmed by Abeta aggregation studies showing that these compounds are able to arrest the metal-promoted increase in amyloid fibril buildup. The fluorescence features of HBX, HBT, BM, and the corresponding iodinated derivatives, together with fluorescence microscopy studies on two types of pregrown fibrils, have shown that HBX and HBT compounds could behave as potential markers for the presence

  2. Intraperitoneal N-acetylcysteine for acute iron intoxication in rats.

    Science.gov (United States)

    Breitbart, Rachelle; Abu-Kishk, Ibrahim; Kozer, Eran; Ben-Assa, Eyal; Goldstein, Lee H; Youngster, Ilan; Berkovitch, Matitiahu

    2011-10-01

    Free radical formation and release of oxidant agents have been suggested as possible mechanisms for tissue damage in acute iron intoxication. N-acetylcysteine (NAC), a glutathione substitute and an antioxidant, is widely used as an antidote for various intoxications. Our aim was to determine whether intraperitoneal (i.p.) NAC would reduce the mortality of rats after acute, toxic oral doses of iron. Male Wistar rats were studied in three phases. In the first phase, animals were assigned to groups 1 (distilled water by gavage) and 2 (i.p. NAC) and observed for survival. In the second phase, rats were assigned to groups 3 (400 mg/kg elemental iron orally) and 4 (400 mg/kg elemental iron, followed by 150 mg/kg i.p. NAC). Survival was observed. Because most rats in Group 3 died within 90 minutes after iron administration, a third phase was conducted in order to allow for comparison of iron and transaminase serum levels after the administration of iron and NAC (group 5: n = 10). Mortality was significantly lower in rats treated with iron and NAC, compared to those treated with iron (P = 0.016). Median serum iron level was significantly lower among rats treated with iron and NAC, compared with rats treated with iron alone (P = 0.002). In a rat model of acute iron intoxication, i.p. administration of NAC may decrease serum iron levels and mortality. PMID:21740343

  3. Pharmacokinetics study of Zr-89-labeled melanin nanoparticle in iron-overload mice.

    Science.gov (United States)

    Zhang, Pengjun; Yue, Yuanyuan; Pan, Donghui; Yang, Runlin; Xu, Yuping; Wang, Lizhen; Yan, Junjie; Li, Xiaotian; Yang, Min

    2016-09-01

    Melanin, a natural biological pigment present in many organisms, has been found to exhibit multiple functions. An important property of melanin is its ability to chelate metal ions strongly, which might be developed as an iron chelator for iron overload therapy. Herein, we prepared the ultrasmall water-soluble melanin nanoparticle (MP) and firstly evaluate the pharmacokinetics of MP in iron-overload mice to provide scientific basis for treating iron-overload. To study the circulation time and biodistribution, MP was labeled with (89)Zr, a long half-life (78.4h) positron-emitting metal which is suited for the labeling of nanoparticles and large bioactive molecule. MP was chelated with (89)Zr directly at pH5, resulting in non-decay-corrected yield of 89.6% and a radiochemical purity of more than 98%. The specific activity was at least190 MBq/μmol. The (89)Zr-MP was stable in human plasma and PBS for at least 48h. The half-life of (89)Zr-MP was about 15.70±1.74h in iron-overload mice. Biodistribution studies and MicroPET imaging showed that (89)Zr-MP mainly accumulated in liver and spleen, which are the target organ of iron-overload. The results indicate that the melanin nanoparticle is promising for further iron overload therapy. PMID:27359110

  4. Staphylococcus aureus redirects central metabolism to increase iron availability.

    Directory of Open Access Journals (Sweden)

    David B Friedman

    2006-08-01

    Full Text Available Staphylococcus aureus pathogenesis is significantly influenced by the iron status of the host. However, the regulatory impact of host iron sources on S. aureus gene expression remains unknown. In this study, we combine multivariable difference gel electrophoresis and mass spectrometry with multivariate statistical analyses to systematically cluster cellular protein response across distinct iron-exposure conditions. Quadruplicate samples were simultaneously analyzed for alterations in protein abundance and/or post-translational modification state in response to environmental (iron chelation, hemin treatment or genetic (Deltafur alterations in bacterial iron exposure. We identified 120 proteins representing several coordinated biochemical pathways that are affected by changes in iron-exposure status. Highlighted in these experiments is the identification of the heme-regulated transport system (HrtAB, a novel transport system which plays a critical role in staphylococcal heme metabolism. Further, we show that regulated overproduction of acidic end-products brought on by iron starvation decreases local pH resulting in the release of iron from the host iron-sequestering protein transferrin. These findings reveal novel strategies used by S. aureus to acquire scarce nutrients in the hostile host environment and begin to define the iron and heme-dependent regulons of S. aureus.

  5. Iron overdose

    Science.gov (United States)

    ... PA: Elsevier Saunders; 2014:chap 147. Liebelt EL. Iron. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose . 4th ed. Philadelphia, PA: Elsevier ...

  6. Complexation of labile aluminium species by chelating resins Iontosorb--a new method for Al environmental risk assessment.

    Science.gov (United States)

    Matús, Peter; Kubová, Jana

    2005-09-01

    The utilization of chelating ion-exchange by the method based on binding strength and kinetic discrimination for aluminium fractionation was studied. Two chelating cellulose resins, Iontosorb Oxin (IO) and Iontosorb Salicyl (IS), were used for the determination of quickly reacting labile aluminium species. The possibilities of aluminium fractionation on these chelating resins were investigated by a solid phase extraction technique. The study of the pH (2.5-6.0) influence on the Al complexation by both resins indicates that at low pH the IS has lower sorption capacity but better adsorptive kinetic properties than IO. The optimal resin complexation time for reactive Al species was experimentally found after aluminium sorption study at pH 4.0 in synthetic solutions containing some inorganic and organic ligands, which simulate the composition of analysed acid soil and water samples. The negative influence of sulphate and iron on the Al complexation by IS resin was found and investigated. The flame atomic absorption spectrometry was used for the aluminium quantification.

  7. Legal considerations involving chemical control of iron and other deficiencies in plants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A; Samman, Y. S.

    1981-01-01

    Four cases of lawsuits involving use of chelating agents in plant nutrition are discussed. Three of them involved use of iron. One concerned addition of FeDTPA to nursery trees in containers. One case involved foliar application of FeHEDTA to potatoes in July by airplane. Another case not involving iron chelate was with ZnEDTA and MnEDTA with Fe as FeSO/sub 4/ later as a foliar spray. The Zn and MnEDTA were applied as a band 8 inches (20 cm) on both sides of nursery tree rows just as the buds that had been placed in the fall began growing in the spring. In the fourth case, many tomato transplants died when the transplanting was done with about 120 ml per plant of transplant solution containing besides N, P and K, about 19 mg Zn as ZnEDTA, 14 mg Mn as MnEDTA and 7 mg Fe as FeHEDTA. Cases such as these will probably discourage use of chelating agents in plant nutrition even if the chelating agents were not the damaging agent. Not enough developmental work was done on the potential toxicities from metal chelates. This trend to lawsuits makes it even more important to solve iron chlorosis problems via plant breeding.

  8. Evaluation of antidiabetic and antioxidant properties of Brucea javanica seed.

    Science.gov (United States)

    Ablat, Abdulwali; Mohamad, Jamaludin; Awang, Khalijah; Shilpi, Jamil A; Arya, Aditya

    2014-01-01

    The ethanol extract of B. javanica seed was fractionated with solvents of different polarities and tested for antioxidant activities by several assays including DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion chelating activity (FCA), and nitric oxide radical scavenging activity (NORSA) along with their polyphenolic contents. Antidiabetic activity was evaluated both in vitro and in vivo using a glycogen phosphorylase α (GPα) inhibition assay and oral glucose tolerance test (OGTT) in nondiabetic rats. The ethyl acetate fraction (EAF), rich in tannin, exhibited the strongest antioxidant activities to DPPH, FRAP, and NORSA, except for FCA. The EAF also exerted a dose-depended inhibition of GPα (IC50 = 0.75 mg/ml). Further evaluation of hypoglycemic effect on OGGT indicated that rats treated with EAF (125 mg/kg bw) showed a 39.91% decrease (P EAF was applied to polyamide column chromatography, and the resulting tannin-free fraction was tested for both GPα inhibition and antioxidant (DPPH only) activity. The GP α inhibitory activity was retained, while antioxidant activity was lost (4.6-fold) after tannin removal. These results concluded that the GPα inhibitory activity initially detected was primarily due to the compounds other than tannins, whereas antioxidant activity was mainly due to the tannins.

  9. FIT interacts with AtbHLH38 and AtbHLH39 in regulating iron uptake gene expression for iron homeostasis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Youxi Yuan; Huilan Wu; Ning Wang; Jie Li; Weina Zhao; Juan Du; Daowen Wang; Hong-Qing Ling

    2008-01-01

    Iron is an essential element for plant growth and development. Iron homeostasis in plants is tightly regulated at both transcriptional and posttranscriptional level. Several bHLH transcription factors involved in iron homeostasis have been identified recently. However, their regulatory mechanisms remain unknown. In this work, we demonstrate that the transcription factor FIT interacted with AtbHLH38 and AtbHLH39 and directly conferred the expression regulation of iron uptake genes for iron homeostasis in Arabidopsis. Yeast two-hybrid analysis and transient expression in Arabidopsis protoplasts showed that AtbH LH38 or AtbHLH39 interacted with FIT, a central transcription factor involved in iron homeostasis in Arabidopsis. Expression of FIT/AtbHLH38 or FIT/AtbHLH39 in yeast cells activated GUS expression driven by ferric chelate reductase (FRO2) and ferrous transporter (IRT1) promoters. Overexpression of FIT with either AtbHLH38 or AtbHLH39 in plants converted the expression of the iron uptake genes FRO2 and IRT1 from induced to constitutive. Further analysis revealed that FR02 and IRT1 were not regulated at the posttranscriptional level in these plants because IRT1 protein accumulation and high ferric chelate reductase activity were detected in the overexpression plants under both iron deficiency and iron sufficiency. The double overexpression plants accumulated more iron in their shoots than wild type or the plants overexpressing either AtbHLH38,AtbHLH39 or FIT. Our data support that ferric-chelate reductase FRO2 and ferrous-transporter IRT1 are the targets of the three transcription factors and the transcription of FRO2 and IRT1 is directly regulated by a complex of FIT/AtbHLH38 or FIT/AtbHLH39.

  10. A reliable procedure for comparison of antioxidants in rat brain homogenates.

    Science.gov (United States)

    Callaway, J K; Beart, P M; Jarrott, B

    1998-04-01

    Lipid peroxidation is a major consequence of oxidative stress and an important cause of neuronal damage in ischaemic injuries and neurodegenerative disorders such as Parkinson's disease. Recent research has focused on the development of antioxidant drugs which may delay or minimize neurodegeneration. Rapid and reliable assays are therefore necessary in order to evaluate novel antioxidant compounds. A widely adopted method for measurement of lipid peroxidation is the thiobarbituric acid reacting substances (TBARS) assay. Several variations of this method have appeared in the literature, some of which have been tested by us without success. We have therefore established a reliable procedure which takes into account the most important factors previously found to influence the TBARS method. Briefly, various concentrations of drug were added to rat brain homogenates (10% w/v in 20 mM Tris-HCl buffer, pH 7.4) and incubated at 37 degrees C for 10 min before addition of ammonium ferric sulphate (100 or 1000 microM) and a further incubation at 37 degrees C for 30 min. Proteins were then precipitated with 8.1% sodium dodecyl sulphate, the reaction stopped with 20% acetic acid, and the samples were then centrifuged for 15 min. Aliquots of supernatant were added to an equal volume of thiobarbituric acid (0.8%), samples were heated at 95 degrees C for 30 min, and then cooled on ice before reading at 532 nm. The present adaptation represents a simple and highly reproducible assay which does not require difficult extraction procedures with hazardous chemicals and results in a stable chromagen. The method has been evaluated using a number of structurally distinct antioxidants and iron chelators. IC50 values (microM) for percentage inhibition of TBARS formation were as follows: desferroxamine (1.1), U83836E (1.7), butylated hydroxytoluene (13), U74500A (20), LY231617 (22), idebenone (89), and Trolox (110). This order of potency was comparable to that found with a commercially

  11. Antioxidant-Induced Stress

    Directory of Open Access Journals (Sweden)

    Robert D. Kross

    2012-02-01

    Full Text Available Antioxidants are among the most popular health-protecting products, sold worldwide without prescription. Indeed, there are many reports showing the benefits of antioxidants but only a few questioning the possible harmful effects of these “drugs”. The normal balance between antioxidants and free radicals in the body is offset when either of these forces prevails. The available evidence on the harmful effects of antioxidants is analyzed in this review. In summary, a hypothesis is presented that “antioxidant-induced stress” results when antioxidants overwhelm the body’s free radicals.

  12. Radiation absorbed doses from iron-52, iron-55, and iron-59 used to study ferrokinetics.

    Science.gov (United States)

    Robertson, J S; Price, R R; Budinger, T F; Fairbanks, V F; Pollycove, M

    1983-04-01

    Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also called idiopathic or hereditary hemochromatosis), pernicious anemia in relapse, iron-deficiency anemia, and polycythemia vera. The Fe-52 doses include the dose from the Mn-52m daughter generated after injection of Fe-52. Special attention has been given to the dose to the spleen, which has a relatively high concentration of RBCs and therefore of radioiron, and which varies significantly in size in both health and disease. PMID:6339690

  13. Radiation absorbed doses from iron-52, iron-55, and iron-59 used to study ferrokinetics

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, J.S.; Price, R.R.; Budinger, T.F.; Fairbanks, V.F.; Pollycove, M.

    1983-04-01

    Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also called idiopathic or hereditary hemochromatosis), pernicious anemia in relapse, iron-deficiency anemia, and polycythemia vera. The Fe-52 doses include the dose from the Mn-52m daughter generated after injection of Fe-52. Special attention has been given to the dose to the spleen, which has a relatively high concentration of RBCs and therefore of radioiron, and which varies significantly in size in both health and disease.

  14. Radiation absorbed doses from iron-52, iron-55, and iron-59 used to study ferrokinetics.

    Science.gov (United States)

    Robertson, J S; Price, R R; Budinger, T F; Fairbanks, V F; Pollycove, M

    1983-04-01

    Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also called idiopathic or hereditary hemochromatosis), pernicious anemia in relapse, iron-deficiency anemia, and polycythemia vera. The Fe-52 doses include the dose from the Mn-52m daughter generated after injection of Fe-52. Special attention has been given to the dose to the spleen, which has a relatively high concentration of RBCs and therefore of radioiron, and which varies significantly in size in both health and disease.

  15. Antioxidant properties of bran extracts from "Akron" wheat grown at different locations.

    Science.gov (United States)

    Yu, Liangli; Perret, Jonathan; Harris, Mary; Wilson, John; Haley, Scott

    2003-03-12

    Bran extracts of Akron wheat grown at four nonirrigated and one irrigated testing locations were examined and compared for their free radical scavenging properties against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)) and the radical cation ABTS(*)(+), chelating capacities, and total phenolic content (TPC) to determine the potential effects of environmental factors on the antioxidant properties of hard winter wheat. The environmental factors included total solar radiation, average daily solar radiation, and number of hours exceeding 32 degrees C. The results showed that bran samples from different growing locations may significantly differ in their radical scavenging activities against both DPPH(*) and ABTS(*)(+), chelating capacities, and TPC. A significant negative correlation was detected between the chelating activities of the bran samples from the four nonirrigated locations and total solar or daily average solar radiation (r = -0.999 and P = 0.001). These data suggest potential influences of growing conditions on the antioxidant properties of hard winter wheat and the possibility of producing wheat that is strong in a selected antioxidant property by optimizing the growing conditions of a selected wheat variety. More research is required to further investigate the relationship among antioxidant properties and environmental factors using different wheat varieties and larger sample sizes. PMID:12617585

  16. The effects of antioxidants and shelf life conditions on oxidation markers in a sunflower oil salad dressing emulsion (SOSDE).

    Science.gov (United States)

    Sainsbury, Jeanine; Grypa, Roman; Ellingworth, John; Duodu, Kwaku G; De Kock, Henriëtta L

    2016-12-15

    The effects of levels of antioxidant [gallic acid or ethylene diamine tetraacetate (EDTA)] in a sunflower oil salad dressing emulsion (SOSDE) and shelf life affecting conditions on aroma, anisidine values (AV) and peroxide values (PV) were determined. Aroma differences between products with different concentrations of antioxidants were more apparent for ambient than accelerated stored SOSDEs. Aroma differences were more noted between SOSDEs with different antioxidants than antioxidant concentrations per se. PV differences between accelerated stored SOSDEs with high and low EDTA concentrations were found. AV differences existed between SOSDEs with different gallic acid concentrations for both storage conditions, and for accelerated stored SOSDEs with different EDTA concentrations. The accelerated storage model is more suitable for SOSDEs with metal chelator antioxidants e.g. EDTA, than free radical scavenging antioxidants e.g. gallic acid. PV, AV and aroma of accelerated stored SOSDEs do not clearly predict ambient shelf life. PMID:27451176

  17. Acetylcholinesterase Inhibition and in Vitro and in Vivo Antioxidant Activities of Ganoderma lucidum Grown on Germinated Brown Rice

    Directory of Open Access Journals (Sweden)

    Beong Ou Lim

    2013-06-01

    Full Text Available In this study, the acetylcholinesterase inhibition and in vitro and in vivo antioxidant activities of Ganoderma lucidum grown on germinated brown rice (GLBR were evaluated. In antioxidant assays in vitro, GLBR was found to have strong metal chelating activity, DPPH, ABTS, hydroxyl and superoxide radical scavenging activity. Cell-based antioxidant methods were used, including lipid peroxidation on brain homogenate and AAPH-induced erythrocyte haemolysis. In antioxidant assays in vivo, mice were administered with GLBR and this significantly enhanced the activities of antioxidant enzymes in the mice sera, livers and brains. The amount of total phenolic and flavonoid compounds were 43.14 mg GAE/g and 13.36 mg CE/g dry mass, respectively. GLBR also exhibited acetylcholinesterase inhibitory activity. In addition, HPLC analyses of GLBR extract revealed the presence of different phenolic compounds. These findings demonstrate the remarkable potential of GLBR extract as valuable source of antioxidants which exhibit interesting acetylcholinesterase inhibitory activity.

  18. Ab initio coordination chemistry for nickel chelation motifs.

    Science.gov (United States)

    Sudan, R Jesu Jaya; Kumari, J Lesitha Jeeva; Sudandiradoss, C

    2015-01-01

    Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  19. Ab initio coordination chemistry for nickel chelation motifs.

    Directory of Open Access Journals (Sweden)

    R Jesu Jaya Sudan

    Full Text Available Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  20. The Effects of Iron Complexing Ligands on the Long Term Ecosystem Response to Iron Enrichment of HNLC waters

    Energy Technology Data Exchange (ETDEWEB)

    Mark L. Wells; Mary Jane Perry; William P. Cochlan; Charles G. Trick

    2006-11-18

    The central hypothesis of this project is that natural iron-complexing organic ligands in seawater differentially regulate iron availability to large (microplankton) and small (nano and picoplankton) class of phytoplankton and thereby strongly influence the potential carbon sequestration in High Nitrate Low Chlorophyll (HNLC) regions of the ocean. The primary project goals are to: 1) determine how different natural and synthetic Fe chelators affect Fe availability to phytoplankton species that are representative of offshore HNLC waters, 2) elucidate how the changes in absolute concentrations of these chelators affect the longer-term ecosystem response to alleviation of Fe limitation, and 3) ascertain how changes in the ligand composition affect rates of cell sinking and aggregation - representative measures of the efficiency of carbon sequestration to the deep.