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Sample records for acid abts radicals

  1. Isolation and Characterization of the 2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) Radical Cation-Scavenging Reaction Products of Arbutin.

    Science.gov (United States)

    Tai, Akihiro; Ohno, Asako; Ito, Hideyuki

    2016-09-28

    Arbutin, a glucoside of hydroquinone, has shown strong 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation-scavenging activity, especially in reaction stoichiometry. This study investigated the reaction mechanism of arbutin against ABTS radical cation that caused high stoichiometry of arbutin in an ABTS radical cation-scavenging assay. HPLC analysis of the reaction mixture of arbutin and ABTS radical cation indicated the existence of two reaction products. The two reaction products were purified and identified to be a covalent adduct of arbutin with an ABTS degradation fragment and 3-ethyl-6-sulfonate benzothiazolone. A time-course study of the radical-scavenging reactions of arbutin and the two reaction products suggested that one molecule of arbutin scavenges three ABTS radical cation molecules to generate an arbutin-ABTS fragment adduct as a final reaction product. The results suggest that one molecule of arbutin reduced two ABTS radical cation molecules to ABTS and then cleaved the third ABTS radical cation molecule to generate two products, an arbutin-ABTS fragment adduct and 3-ethyl-6-sulfonate benzothiazolone.

  2. Two New Saccharide Fatty Acid Esters from the Fruit of Morinda citrifolia L. and Their ABTS Radical Scavenging Activities

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    Hong-Cai Zhang

    2014-01-01

    Full Text Available Two n ew saccharide fatty acid esters (1 and (2, and six other compounds were isolated from the fruit of Morinda citrifolia L. (Rubiaceae The structures were established as (2E-oct-2-enoate-2-O-β-D - glucopyranosyl-β-D-glucopyranoside(1, (2E-2,6-dimethyl -6-hydroxyl-oct-2,7-dienoate-2-O-β-D-glucopyranosyl-β-D-glucopyranoside(2, saccharumoside C(3, O-β-D-apiofuranosyl-(1→6-O-β-D-glucopyranosides of 3-methyl-2-butenol(4, 3-methyl-but-2-en-1-yl β-D-glucopyranosyl (1→6-β-D-glucopyranoside(5, benzyl - glucopyranoside(6, Hexyl-O-β-D-glucopyranoside(7, and caproic acid(8. Compound 1 and 2 showed moderate activity against ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonate radical in concentration of 0.1-3.2 mg/mL. Morinda citrifolia L., saccharide fatty acid ester, ABTS radical scavenging activity

  3. Doxorubicin inhibits oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) by a lactoperoxidase/H(2)O(2) system by reacting with ABTS-derived radical.

    Science.gov (United States)

    Reszka, Krzysztof J; Britigan, Bradley E

    2007-10-15

    The effect of doxorubicin on oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) by lactoperoxidase and hydrogen peroxide has been investigated. It was found that: (1) oxidation of ABTS to its radical cation (ABTS*(+)) is inhibited by doxorubicin as evidenced by its induction of a lag period, duration of which depends on doxorubicin concentration; (2) the inhibition is due to doxorubicin hydroquinone reducing the ABTS*(+) radical (stoichiometry 1: 1.8); (3) concomitant with the ABTS*(+) reduction is oxidation of doxorubicin; only when the doxorubicin concentration decreases to a near zero level, net oxidation of ABTS could be detected; (4) oxidation of doxorubicin leads to its degradation to 3-methoxysalicylic acid and 3-methoxyphthalic acid; (5) the efficacy of doxorubicin to quench ABTS*(+) is similar to the efficacy of p-hydroquinone, glutathione and Trolox C. These observations support the assertion that under certain conditions doxorubicin can function as an antioxidant. They also suggest that interaction of doxorubicin with oxidants may lead to its oxidative degradation.

  4. The Scavenging of DPPH, Galvinoxyl and ABTS Radicals by Imine Analogs of Resveratrol.

    Science.gov (United States)

    Kotora, Peter; Šeršeň, František; Filo, Juraj; Loos, Dušan; Gregáň, Juraj; Gregáň, Fridrich

    2016-01-21

    Resveratrol (3,5,4'-trihydroxystilbene) is a phytoalexin produced by plants. Resveratrol is known for its anti-cancer, antiviral and antioxidant properties. We prepared imine analogs of resveratrol ((hydroxyphenyliminomethyl)phenols) and tested their antioxidant activity. All prepared resveratrol analogs were able to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR) and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) radicals. The antioxidant activity efficiency correlated with the number and position of hydroxyl groups. The most effective antioxidants were resveratrol analogs containing three hydroxyl groups in the benzylidene part of their molecules. These results provide new insights into the relationship between the chemical structure and biological activity of resveratrol analogs.

  5. The Scavenging of DPPH, Galvinoxyl and ABTS Radicals by Imine Analogs of Resveratrol

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    Peter Kotora

    2016-01-01

    Full Text Available Resveratrol (3,5,4′-trihydroxystilbene is a phytoalexin produced by plants. Resveratrol is known for its anti-cancer, antiviral and antioxidant properties. We prepared imine analogs of resveratrol ((hydroxyphenyliminomethylphenols and tested their antioxidant activity. All prepared resveratrol analogs were able to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH, galvinoxyl radical (GOR and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS radicals. The antioxidant activity efficiency correlated with the number and position of hydroxyl groups. The most effective antioxidants were resveratrol analogs containing three hydroxyl groups in the benzylidene part of their molecules. These results provide new insights into the relationship between the chemical structure and biological activity of resveratrol analogs.

  6. Alteration of fatty acids content during cow's and goat's milk fermentation with ABT-2 culture

    OpenAIRE

    Vedran Slačanac; Jovica Hardi; Hrvoje Pavlović; Mato Vlainić; Mirela Lučan

    2005-01-01

    In this paper, changes in composition and contents of each fatty acid during fermentation with ABT-2 culture were examined. The objective of this study was to determinate the increase of short (SCFA) and medium (MCFA) chain fatty acids in goat's and cow's milk during fermentation with ABT-2 culture. The hypothesis of this study was that higher contents of SCFA and MCFA are produced in goat's milk in comparison with cow's milk, during fermentation with ABT-2 culture. Obtained results have show...

  7. Phytochemical profile and ABTS cation radical scavenging, cupric reducing antioxidant capacity and anticholinesterase activities of endemic Ballota nigra L. subsp. anatolica P.H. Davis from Turkey

    Institute of Scientific and Technical Information of China (English)

    Abdulselam Erta; Mehmet Boa; Yeter Yeil

    2014-01-01

    Objective: To evaluate the chemical compositions and biological activities of an endemic Ballotanigra Methods: Essential oil and fatty acid composition were determined by GC/MS analysis. ABTS cation radical decolourisation and cupric reducing antioxidant capacity assays were carried out to indicate the antioxidant activity. The anticholinesterase potential of the extracts were determined by Ellman method. L. subsp. anatolica P.H. Davis. Results: The major compounds in the fatty acid composition of the petroleum ether extract were identified as palmitic (36.0%) and linoleic acids (14.3%). The major components of essential oil were 1-hexacosanol (26.7%), germacrene-D (9.3%) and caryophyllene oxide (9.3%). The water extract indicated higher ABTS cation radical scavenging activity than α-tocopherol and BHT, at 100 µg/mL. The acetone extract showed 71.58 and 44.71% inhibitory activity against butyrylcholinesterase and acetylcholinesterase enzyme at 200 µg/mL, respectively. Conclusions: The water and acetone extracts of Ballota nigra subsp. anatolica can be investigated in terms of both phytochemical and biological aspects to find natural active compounds.

  8. Histamine H3 receptor antagonism by ABT-239 attenuates kainic acid induced excitotoxicity in mice.

    Science.gov (United States)

    Bhowmik, Malay; Saini, Neeru; Vohora, Divya

    2014-09-18

    The multifaceted pathogenesis of temporal lobe epilepsy (TLE) offers a number of adjunctive therapeutic prospects. One such therapeutic strategy could be targeting H3 receptor (H3R) by selective H3R antagonists which are perceived to have antiepileptic and neuroprotective potential. Kainic acid (KA) induced seizure, a reliable model of TLE, triggers epileptogenic events resulting from initial neuronal death and ensuing recurring seizures. The present study aimed to determine whether pre-treatment with ABT-239, a novel H3R antagonist, and its combinations with sodium valproate (SVP) and TDZD-8 (glycogen synthase kinase-3β (GSK3β) inhibitor) can prevent the excitotoxic events in mice exposed to KA (10 mg/kg i.p.). ABT-239 (1 and 3 mg/kg i.p.) significantly attenuated KA-mediated behavioural and excitotoxic anomalies and restored altered expression of Bax, cleaved caspase-3, phospho-Akt (Ser473) and cAMP response element binding protein (CREB). Surprisingly, restoration of Bcl2 and phospho-GSK3β (Ser9) by ABT-239 did not reach the level of statistical significance. Co-administration of ABT-239 (1 and 3 mg/kg) with a sub-effective dose of SVP (150 mg/kg i.p.) yielded improved efficacy than when given alone. Similarly, low and high dose combinations of ABT-239 (1 and 3 mg/kg) with TDZD-8 (5 and 10 mg/kg i.p.) produced greater neuroprotection than any other treatment group. Our findings suggests a neuroprotective potential of ABT-239 and its combinations with SVP and TDZD-8 against KA-induced neurotoxicity, possibly mediated through in part each by modulating Akt/GSK3β and CREB pathways. The use of H3R antagonists as adjuvant in the treatment of human TLE might find potential utility, and can be pursued further.

  9. Methylseleninic acid potentiates multiple types of cancer cells to ABT-737-induced apoptosis by targeting Mcl-1 and Bad

    DEFF Research Database (Denmark)

    Yin, Shutao; Dong, Yinhui; Li, Jinghua

    2012-01-01

    ABT-737, a novel small molecule inhibitor of Bcl-2 family proteins, holds great promise to complement current cancer therapies. However many types of solid cancer cells are resistant to ABT-737. One practical approach to improve its therapeutic efficacy is to combine with the agents that can...... overcome such resistance to restore the sensitivity. In the present study, a second-generation selenium compound methylseleninic acid (MSeA) synergistically sensitized MDA-MB-231 human breast cancer cells, HT-29 human colon cancer cells and DU145 human prostate cancer cells to apoptosis induction by ABT......-737, as evidenced by greater than additive enhancement of Annexin V/FITC positive (apoptotic) cells and activation of multiple caspases and PARP cleavage. Mechanistic investigation demonstrated that MSeA significantly decreased basal Mcl-1 expression and ABT-737-induced Mcl-1 expression. Knocking down...

  10. The BH3-mimetic ABT-737 targets the apoptotic machinery in cholangiocarcinoma cell lines resulting in synergistic interactions with zoledronic acid

    OpenAIRE

    ROMANI, ANTONELLO A.; Desenzani, Silvia; Morganti, Marina M.; Baroni, Maria Cristina; Borghetti, Angelo F.; Soliani, Paolo

    2010-01-01

    Abstract Purpose In TFK-1 and EGI-1 cholangiocarcinoma cell lines, zoledronic acid (ZOL) determines an S-phase block without apoptosis. Here, we investigated the occurrence of apoptosis stigmata when ZOL is associated to the BH3-mimetic ABT-737. Methods In EGI-1 and TFK-1 cholangiocarcinoma cell lines untreated or treated with ABT-737 alone or in combination with ZOL, the pro-survival protein?s pattern (BC...

  11. Isoprene, sulphoxy radical-anions and acidity

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    K. J. Rudziński

    2008-12-01

    Full Text Available Transformation of isoprene coupled with autoxidation of SIV in aqueous solutions was studied experimentally and by chemical-kinetic modelling over broad range of solution acidities (pH=3–9 to complement the research on aqueous-phase and heterogeneous transformation of isoprene reported recently by many laboratories. Isoprene significantly slowed down the autoxidation in acidic and basic solutions, and accelerated it slightly in neutral solutions. Simultaneously, production of sulphate ions and formation of solution acidity were significantly reduced. Formation of sulphite and sulphate derivatives of isoprene – sulphurous acid mono-(2-methyl-4-oxo-but-2-enyl ester (m/z=162.9, sulphurous acid mono-(4-hydroxy-2-methyl-but-2-enyl ester (m/z=164.9, sulphuric acid mono-(2-methyl-4-oxo-but-2-enyl ester (m/z=178.9, sulphuric acid mono-(4-hydroxy-2-methyl-but-2-enyl ester (m/z=180.9 – was indicated by mass spectroscopic analysis of post-reaction mixtures. The results of experiments were explained by changes in a subtle quantitative balance of three superimposed processes whose rates depended in different manner on the acidity of reacting solutions – the scavenging of sulphoxy radicals by isoprene, the formation of sulphoxy radicals during further reactions of isoprene radicals, and the autoxidation of SIV itself. A chemical mechanism based on this idea was explored numerically to show good agreement with experimental data. Interaction of isoprene with sulphur(IV species and oxygen can possibly result in formation of new organosulphate components of atmospheric aerosols and waters, and influence distribution of reactive sulphur and oxygen species in isoprene-emitting organisms exposed to SIV pollutants.

  12. Pathways of arachidonic acid peroxyl radical reactions and product formation with guanine radicals.

    Science.gov (United States)

    Crean, Conor; Geacintov, Nicholas E; Shafirovich, Vladimir

    2008-02-01

    Peroxyl radicals were derived from the one-electron oxidation of polyunsaturated fatty acids by sulfate radicals that were generated by the photodissociation of peroxodisulfate anions in air-equilibrated aqueous solutions. Reactions of these peroxyl and neutral guanine radicals, also generated by oxidation with sulfate radicals, were investigated by laser kinetic spectroscopy, and the guanine oxidation products were identified by HPLC and mass spectrometry methods. Sulfate radicals rapidly oxidize arachidonic (ArAc), linoleic (LnAc), and palmitoleic (PmAc) acids with similar rate constants, (2-4) x 10 (9) M (-1) s (-1). The C-centered radicals derived from the oxidation of ArAc and LnAc include nonconjugated Rn(.) ( approximately 80%) and conjugated bis-allylic Rba(.) ( approximately 20%) radicals. The latter were detectable in the absence of oxygen by their prominent, narrow absorption band at 280 nm. The Rn(.) radicals of ArAc (containing three bis-allylic sites) transform to the Rba(.) radicals via an intramolecular H-atom abstraction [rate constant (7.5 +/- 0.7) x 10 (4) s (-1)]. In contrast, the Rn(.) radicals of LnAc that contain only one bis-allylic site do not transform intramolecularly to the Rba(.) radicals. In the case of PmAc, which contains only one double bond, the Rba(.) radicals are not observed. The Rn(.) radicals of PmAc rapidly combine with oxygen with a rate constant of (3.8 +/- 0.4) x 10(9) M(-1) s(-1). The Rba(.) radicals of ArAc are less reactive and react with oxygen with a rate constant of (2.2 +/- 0.2) x 10 (8) M (-1) s (-1). The ArAc peroxyl radicals formed spontaneously eliminate superoxide radical anions [rate constant = (3.4 +/- 0.3) x 10 (4) M (-1) s (-1)]. The stable oxidative lesions derived from the 2',3',5'-tri- O-acetylguanosine or 2',3',5'-tri- O-acetyl-8-oxo-7,8-dihydroguanosine radicals and their subsequent reactions with ArAc peroxyl radicals were also investigated. The major products found were the 2,5-diamino-4 H

  13. In Vitro Antioxidant-Activity Evaluation of Gallic-Acid-Grafted Chitosan Conjugate Synthesized by Free-Radical-Induced Grafting Method.

    Science.gov (United States)

    Hu, Qiaobin; Wang, Taoran; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-07-27

    The major objective of this work was to develop a green and facile process to prepare gallic acid-chitosan conjugate and comprehensively evaluate the physicochemical properties and biological activities of an as-prepared water-soluble chitosan derivative. A free-radical-induced grafting approach using an ascorbic acid-hydrogen peroxide redox pair was adopted. The obtained conjugate was characterized by Fourier transform infrared spectroscopy, UV-vis, X-ray diffraction, and pKa analysis. The antioxidant activities were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6)-sulphonic acid (ABTS), reducing power, and oxygen-radical antioxidant-capacity assays. The results showed that the mass ratio of gallic acid to chitosan played a vital role in determining the grafting degree and ζ potential of the conjugates, with the ratio of 0.5:1 being the optimal ratio that resulted in the highest grafting degree. The antioxidant assays demonstrated that conjugation significantly improved the antioxidant activities, being dramatically higher than that of free chitosan. It was notable that the DPPH- and ABTS-scavenging activities of conjugate at 0.4 mg/mL reached the same level as the free gallic acid at the equivalent concentration. Our study demonstrated a green and facile synthesis approach to preparing a novel water-soluble chitosan derivative that may have promising potentials in the food industry.

  14. Determination of protective properties of Bardejovske Kuple spa curative waters by rotational viscometry and ABTS assay

    Directory of Open Access Journals (Sweden)

    TOPOLSKA Dominika

    2014-02-01

    Full Text Available Mineral waters from Bardejovske Kupele spa are natural, strongly mineralized, with healing effects. They are classified as hydrocarbonic - containing chloride and sodium - carbonic, cold, hypotonic, with a relatively high boric acid content. Potential anti-oxidative effects of curative waters from Bardejovske Kupele were investigated against the hyaluronan (HA degradation. High-molar-mass HA was exposed to the action of ascorbate and cupric ions, which initiate free-radical chain degradation. Time-dependent changes of dynamic viscosity (h of the HA solutions were monitored by rotational viscometry. The radical scavenging capacity of curative waters was determined by the ABTS assay. Despite a significantly high content of transition metal ions, especially iron, remarkable protective effects of the two curative spa waters were found, namely Alzbeta and Klara. Even though “Alzbeta´s“ iron content was 3.5-fold higher than “Klara´s“, “Alzbeta“ was shown to have better protective properties against the HA degradation compared to “Klara“. Bolus addition of ferric ions to the reaction system instead of the natural iron-containing curative water caused a significant HA degradation. The ABTS decolorization assay revealed that the curative spa waters were proven as poorly effective scavengers of the ABTS·+ cation radical.

  15. Antioxidant activity of selected phenols estimated by ABTS and FRAP methods

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    Izabela Biskup

    2013-09-01

    Full Text Available Introduction: Phenols are the most abundant compounds in nature. They are strong antioxidants. Too high level of free radicals leads to cell and tissue damage, which may cause asthma, Alzheimer disease, cancers, etc. Taking phenolics with the diet as supplements or natural medicines is important for homeostasis of the organism. Materials and methods: The ten most popular water soluble phenols were chosen for the experiment to investigate their antioxidant properties using ABTS radical scavenging capacity assay and ferric reducing antioxidant potential (FRAP assay. Results and discussion: Antioxidant properties of selected phenols in the ABTS test expressed as IC50 ranged from 4.332 μM to 852.713 μM (for gallic acid and 4- hydroxyphenylacetic acid respectively. Antioxidant properties in the FRAP test are expressed as μmol Fe2 /ml. All examined phenols reduced ferric ions at concentration 1.00 x 10-3 mg/ml. Both methods are very useful for determination of antioxidant capacity of water soluble phenols.

  16. Inhibition of lactoperoxidase-catalyzed 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and tyrosine oxidation by tyrosine-containing random amino acid copolymers.

    Science.gov (United States)

    Clausen, Morten R; Skibsted, Leif H; Stagsted, Jan

    2008-09-24

    Oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) by lactoperoxidase was found to be inhibited by tyrosine-containing random amino acid copolymers but not by tyrosine. Both electrostatic effects and polymer size were found to be important by comparison of negatively and positively charged copolymers of varying lengths, with poly(Glu, Tyr)4:1 ([E 4Y 1] approximately 40) as the strongest competitive inhibitor (EC 50 approximately 20 nM). This polymer did not form dityrosine in the presence of lactoperoxidase (LPO) and peroxide. Furthermore, incubation with tert-butyl hydroperoxide, as opposed to hydrogen peroxide, resulted in a peculiar long lag phase of the reaction between the redox intermediate compound II and [E 4Y 1] approximately 40, indicating a very tight association between enzyme and inhibitor. We propose that interactions between multiple positively charged areas on the surface of LPO and the polymer are required for optimal inhibition.

  17. Determination of peroxy radical-scavenging of lactic acid bacteria.

    Science.gov (United States)

    Stecchini, M L; Del Torre, M; Munari, M

    2001-02-28

    Responses of lactic acid bacteria (LAB) to peroxy radicals generated via thermal (40 degrees C) decomposition of the diazocompound 2,2,-azo-bis (2-amidinopropane) dihydrochloride (ABAP), were studied. In general, LAB displayed survival curves with shoulders and tails indicative of 'multihit' killing by exposure to peroxy radicals. One strain, Lactococcus lactis subsp. lactis DIP15, producing a slope of 0.0105 in the kinetic analysis when exposed to 4 mM ABAP, exhibited a measurable antioxidant capacity. The other LAB failed to show any significant antioxidant capacity. The antioxidant capacity of strain DIP15 remained constant after cells have been heat-treated, suggesting that compounds bearing free radical scavenging capacity are rather stable.

  18. ABTS-Modified Silica Nanoparticles as Laccase Mediators for Decolorization of Indigo Carmine Dye

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    Youxun Liu

    2015-01-01

    Full Text Available Efficient reuse and regeneration of spent mediators are highly desired for many of the laccases’ biotechnology applications. This investigation demonstrates that a redox mediator 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS covalently attached to silica nanoparticles (SNPs effectively mediated dye decolorization catalyzed by laccase. Characteristics of ABTS-modified silica nanoparticles (ABTS-SNPs were researched by scanning electron microscopy and Fourier-transformed infrared spectroscopy. When ABTS and ABTS-SNPs were used as laccase mediators, the decolorization yields of 96 and 95% were, respectively, obtained for indigo carmine dye. The results suggest that ABTS immobilized on SNPs can be used as laccase mediators as they retain almost the same efficiency as the free ABTS. The oxidized ABTS-SNPs were regenerated by their reduction reaction with ascorbic acid. Decolorization efficiency of regenerated ABTS-SNPs and their initial forms were found to be almost equivalent. Six reuse cycles for spent ABTS-SNPs were run for the treatment of indigo carmine, providing decolorization yields of 96–77%. Compared with free mediator, the immobilized mediators have the advantage of being easily recovered, regenerated, and reused making the whole process environmentally friendly.

  19. Spectroscopic detection, reactivity, and acid-base behavior of ring-dimethoxylated phenylethanoic acid radical cations and radical zwitterions in aqueous solution.

    Science.gov (United States)

    Bietti, Massimo; Capone, Alberto

    2004-01-23

    A product and time-resolved kinetic study of the one-electron oxidation of ring-dimethoxylated phenylethanoic acids has been carried out at different pH values. Oxidation leads to the formation of aromatic radical cations or radical zwitterions depending on pH, and pK(a) values for the corresponding acid-base equilibria have been measured. The radical cations undergo decarboxylation with first-order rate constants (k(dec)) ranging from <10(2) to 5.6 x 10(4) s(-1) depending on radical cation stability. A significant increase in k(dec) (between 10 and 40 times) is observed on going from the radical cations to the corresponding radical zwitterions. The results are discussed in terms of the ease of intramolecular side chain to ring electron transfer required for decarboxylation, in both the radical cations and radical zwitterions.

  20. Study of genotoxic, antigenotoxic and antioxidant activities of the digallic acid isolated from Pistacia lentiscus fruits.

    Science.gov (United States)

    Bhouri, Wissem; Derbel, Safa; Skandrani, Ines; Boubaker, Jihed; Bouhlel, Ines; Sghaier, Mohamed B; Kilani, Soumaya; Mariotte, Anne M; Dijoux-Franca, Marie G; Ghedira, Kamel; Chekir-Ghedira, Leila

    2010-03-01

    The digallic acid obtained from the fruit Pistacia lentiscus exhibits an inhibitory activity against nitrofurantoine and B[a]P induced genotoxicity when tested by the SOS chromotest bacterial assay system in the presence of Escherichia coli PQ37 strain. The antioxidant activity of the tested compound was determined by its ability to scavenge the free radical ABTS(+), to inhibit the xanthine oxidase, involved in the generation of free radicals, and to inhibit the lipid peroxidation induced by H(2)O(2) in the K562 cell line. Our results revealed that digallic acid shows an important free radical scavenging activity towards the ABTS(+) radical (99%) and protection against lipid peroxidation (68%).

  1. Mechanism of protection of adenosine from sulphate radical anion and repair of adenosine radicals by caffeic acid in aqueous solution

    Indian Academy of Sciences (India)

    M Sudha Swaraga; L Charitha; M Adinarayana

    2005-07-01

    The photooxidation of adenosine in presence of peroxydisulphate (PDS) has been studied by spectrophotometrically measuring the absorbance of adenosine at 260 nm. The rates of oxidation of adenosine by sulphate radical anion have been determined in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation of adenosine suggesting that caffeic acid acts as an efficient scavenger of $SO_{4}^{\\bullet-}$ and protects adenosine from it. Sulphate radical anion competes for adenosine as well as for caffeic acid. The quantum yields of photooxidation of adenosine have been calculated from the rates of oxidation of adenosine and the light intensity absorbed by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined quantum yields (exptl) and the quantum yields calculated (cal) assuming caffeic acid acting only as a scavenger of $SO_{4}^{\\bullet-}$ show that exptl values are lower than cal values. The ' values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected for $SO_{4}^{\\bullet-}$ scavenging by caffeic acid, are also found to be greater than exptl values. These observations suggest that the transient adenosine radicals are repaired by caffeic acid in addition to scavenging of sulphate radical anions.

  2. Ellagic acid inhibits iron-mediated free radical formation

    Science.gov (United States)

    Dalvi, Luana T.; Moreira, Daniel C.; Andrade, Roberto; Ginani, Janini; Alonso, Antonio; Hermes-Lima, Marcelo

    2017-02-01

    Polyphenols are reported to have some health benefits, which are link to their antioxidant properties. In the case of ellagic acid (EA), there is evidence that it has free radical scavenger properties and that it is able to form complexes with metal ions. However, information on a possible link between the formation of iron-EA complexes and their interference in Haber-Weiss/Fenton reactions was not yet determined. Thus, the present study investigated the in vitro antioxidant mechanism of EA in a system containing ascorbate, Fe(III) and different iron ligands (EDTA, citrate and NTA). Iron-mediated oxidative degradation of 2-deoxyribose was poorly inhibited (by 12%) in the presence of EA (50 μM) and EDTA. When citrate or NTA - which form weak iron complexes - were used, the 2-deoxyribose protection increased to 89-97% and 45%, respectively. EA also presented equivalent inhibitory effects on iron-mediated oxygen uptake and ascorbyl radical formation. Spectral analyses of iron-EA complexes show that EA removes Fe(III) from EDTA within hours, and from citrate within 1 min. This difference in the rate of iron-EA complex formation may explain the antioxidant effects of EA. Furthermore, the EA antioxidant effectiveness was inversely proportional to the Fe(III) concentration, suggesting a competition with EDTA. In conclusion, the results indicate that EA may prevent in vitro free radical formation when it forms a complex with iron ions.

  3. Radical and Non-Radical Mechanisms for Alkane Oxidations by Hydrogen Peroxide-Trifluoroacetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Camaioni, Donald M.; Bays, J. Timothy; Shaw, Wendy J.; Linehan, John C.; Birnbaum, Jerome C.

    2001-02-01

    The oxidation of cyclohexane by the H2O2-trifluoroacetic acid system is revisited. Consistent with a previous report (Deno, N.; Messer, L. A. Chem. Comm. 1976, 1051), cyclohexanol forms initially but then esterifies to cyclohexyl trifluoroacetate. Small amounts of trans-1,2-cyclohexadiyl bis(trifluoroacetate) also form. Although these products form irrespective of the presence or absence of O2, dual mechanisms are shown to operate. In the absence of O2, the dominant mechanism is a radical chain reaction that is propagated by CF3• abstracting H from C6H12 and SH2 displacement of C6H11• on CF3CO2OH. The intermediacy of C6H11• and CF3• is inferred from production of CHF3 and CO2 along with cyclohexyl trifluoroacetate, or CDF3 when cyclohexane-d12 is used. In the presence of O2, fluoroform and CO2 are suppressed, the reaction rate slows, and the rate law approaches second order (first order in peracid and in C6H12). Trapping of cyclohexyl radicals by quinoxaline is inefficient except at elevated (75 °C) temperatures. Fluoroform and CO2, telltale evidence for the chain pathway, were not produced when quinoxaline was present in room temperature reactions. These observations suggest that a parallel, nonfree radical, oxenoid insertion mechanism dominates when O2 is present. A pathway is discussed in which a biradicaloid-zwiterionic transition state is attained by hydrogen transfer from alkane to peroxide oxygen with synchronous O-O bond scission.

  4. Application of living free radical polymerization for nucleic acid delivery.

    Science.gov (United States)

    Chu, David S H; Schellinger, Joan G; Shi, Julie; Convertine, Anthony J; Stayton, Patrick S; Pun, Suzie H

    2012-07-17

    Therapeutic gene delivery can alter protein function either through the replacement of nonfunctional genes to restore cellular health or through RNA interference (RNAi) to mask mutated and harmful genes. Researchers have investigated a range of nucleic acid-based therapeutics as potential treatments for hereditary, acquired, and infectious diseases. Candidate drugs include plasmids that induce gene expression and small, interfering RNAs (siRNAs) that silence target genes. Because of their self-assembly with nucleic acids into virus-sized nanoparticles and high transfection efficiency in vitro, cationic polymers have been extensively studied for nucleic acid delivery applications, but toxicity and particle stability have limited the clinical applications of these systems. The advent of living free radical polymerization has improved the quality, control, and reproducibility of these synthesized materials. This process yields well-defined, narrowly disperse materials with designed architectures and molecular weights. As a result, researchers can study the effects of polymer architecture and molecular weight on transfection efficiency and cytotoxicity, which will improve the design of next-generation vectors. In this Account, we review findings from structure-function studies that have elucidated key design motifs necessary for the development of effective nucleic acid vectors. Researchers have used robust methods such as atom transfer radical polymerization (ATRP), reverse addition-fragmentation chain transfer polymerization (RAFT), and ring-opening metastasis polymerization (ROMP) to engineer materials that enhance extracellular stability and cellular specificity and decrease toxicity. In addition, we discuss polymers that are biodegradable, form supramolecular structures, target specific cells, or facilitate endosomal release. Finally, we describe promising materials with a range of in vivo applications from pulmonary gene delivery to DNA vaccines.

  5. Electrochemistry of ABTS at Glassy Carbon Electrodes

    Institute of Scientific and Technical Information of China (English)

    Han Zeng; Zhi-qiang Tang; Ling-wen Liao; Jing Kang; Yan-xia Chen

    2011-01-01

    The electrochemical and the mass transport behavior of ABTS2-/ABTS- (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate)) redox couple at glassy carbon electrode (GCE) in phosphate buffer solution (PBS,pH=4.4) is studied in detail by cyclic voltammetry combined with rotating disk electrode system.From the i-E curves recorded at different electrode rotating rate,rate constant,and transfer coefficient for ABTS 2-(≒)ABTS-+e reaction at GCE electrode and the diffusion coefficient of ABTS2- in PBS are estimated to be 4.6× 10-3 cm/s,0.28,and 4.4× 10-6 cm2/s,respectively.The transfer coefficient with a value of ca.0.28 differs largely from the value of 0.5 that is always assumed in the literature.The origins for the difference of the rate constant determined and the challenges for estimating the standard rate constant are discussed.The performance for such ABTS2- mediated bio-cathode toward oxygen reduction reaction is discussed according to the over-potential drop as well as current output limit associated with the charge transfer kinetics of ABTS2- (≒)ABTS- +e redox reaction and/or the mass transport effect.

  6. Formation of hydroxyl radical from the photolysis of salicylic acid.

    Science.gov (United States)

    Zhou, Can-Hua; Cheng, Shi-Bo; Yin, Hong-Ming; He, Guo-Zhong

    2011-05-26

    Photodissociation dynamics of salicylic acid (SA) in the gas phase at different photolysis wavelengths (266, 315-317 nm) is investigated by probing the nascent OH photoproduct employing the single-photon laser-induced fluorescence (LIF) technique. At all the photolysis wavelengths it is found that the nascent OH radicals are produced mostly in a vibrationally ground state (υ'' = 0) and have similar rotational state distributions. The two spin-orbit and Λ-doublet states of the OH fragment formed in the dissociation are measured to have a nonstatistical distribution at each photolysis wavelength. The LIF signal of the OH could be observed upon photolysis at 317 nm but not at 317.5 nm. The threshold of OH formation from SA photodissociation is estimated to be 98.2 ± 0.9 kcal/mol. The effect of the phenolic OH group on the dissociation of SA is discussed.

  7. Reactions of linoleic acid peroxyl radicals with phenolic antioxidants: a pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Erben-Russ, M.; Bors, W.; Saran, M.

    1987-09-01

    Linoleic acid peroxyl radicals (LOO) can be viewed as model intermediates occurring during lipid peroxidation processes. Formation and reactions of these species were investigated in aqueous alkaline solution using pulse radiolysis combined with kinetic spectroscopy. Irradiation of linoleic acid in N/sub 2/O/O/sub 2/-saturated solutions leads to a mixture of peroxyl radical isomers; reaction of 13-hydroperoxylinoleic acid (13-LOOH) with azide radicals in N/sub 2/O-saturated solution produces 13-LOO radicals specifically. These peroxyl radicals cannot be observed directly, but their reactions with kaempferol and quercetin, acting as radical-scavenging antioxidants, produced strongly absorbing aroxyl radicals (ArO). The same aroxyl radicals were generated by OH and N/sub 3/ with rate constants exceeding 10/sup 9/ dm/sup 3/ mol/sup -1/ s/sup -1/. Applying a reaction scheme that includes competing generation and decay reactions of both LOO and ArO radicals, individual rate constants were derived for LOO reactions with the phenols (> 10/sup 7/ dm/sup 3/ mol/sup -1/ s-./sup 1/), with aroxyl radicals to form covalent adducts (> 10/sup 8/ dm/sup 3/ mol/sup -1/ s/sup -1/), as well as for their bimilecular decay (3.0 x 10/sup 8/ dm/sup 3/ mol/sup -1/ s/sup -1/). These results demonstrate high reactivity of fatty acid peroxyl radicals and flavone antioxidants in aqueous solution.

  8. Radical-cationic gaseous amino acids: a theoretical study.

    Science.gov (United States)

    Sutherland, Kailee N; Mineau, Philippe C; Orlova, Galina

    2007-08-16

    Three major forms of gaseous radical-cationic amino acids (RCAAs), keto (COOH), enolic (C(OH)OH), and zwitterionic (COO(-)), as well as their tautomers, are examined for aliphatic Ala(.+), Pro(.+), and Ser(.+), sulfur-containing Cys(.+), aromatic Trp(.+), Tyr(.+), and Phe(.+), and basic His(.+). The hybrid B3LYP exchange-correlation functional with various basis sets along with the highly correlated CCSD(T) method is used. For all RCAAs considered, the main stabilizing factor is spin delocalization; for His(.+), protonation of the basic side chain is equally important. Minor stabilizing factors are hydrogen bonding and 3e-2c interactions. An efficient spin delocalization along the N-C(alpha)-C(O-)O moiety occurs upon H-transfer from C(alpha) to the carboxylic group to yield the captodative enolic form, which is the lowest-energy isomer for Ala(.+), Pro(.+), Ser(.+), Cys(.+), Tyr(.+), and Phe(.+). This H-transfer occurs in a single step as a 1,3-shift through the sigma-system. For His(.+), the lowest-energy isomer is formed upon H-transfer from C(alpha) to the basic side chain, which results in a keto form, with spin delocalized along the N-C(alpha)-C=O fragment. Trp(.+) is the only RCAA that favors spin delocalization over an aromatic system given the low ionization energy of indole. The lowest-energy isomer of Trp(.+) is a keto form, with no H-transfer.

  9. Reactivity of phenolic compounds towards free radicals under in vitro conditions.

    Science.gov (United States)

    Mathew, Sindhu; Abraham, T Emilia; Zakaria, Zainul Akmar

    2015-09-01

    The free radical scavenging activity and reducing power of 16 phenolic compounds including four hydroxycinnamic acid derivatives namely ferulic acid, caffeic acid, sinapic acid and p-coumaric acid, benzoic acid and its derivatives namely protocatechuic acid, gallic acid and vanillic acid, benzene derivatives namely vanillin, vanillyl alcohol, veratryl alcohol, veratraldehyde, pyrogallol, guaiacol and two synthetic antioxidants, butylated hydroxy anisole (BHA) and propyl gallate were evaluated using 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH(•)), 2,2'-Azinobis-3- ethylbenzothiazoline-6-sulfonic acid radical (ABTS(+•)), Hydroxyl radical ((•)OH) and Superoxide radical (O2 (•-)) scavenging assays and reduction potential assay. By virtue of their hydrogen donating ability, phenolic compounds with multiple hydroxyl groups such as protocatechuic acid, pyrogallol, caffeic acid, gallic acid and propyl gallate exhibited higher free radical scavenging activity especially against DPPH(•) and O2 (•-). The hydroxylated cinnamates such as ferulic acid and caffeic acid were in general better scavengers than their benzoic acid counter parts such as vanillic acid and protocatechuic acid. All the phenolic compounds tested exhibited more than 85 % scavenging due to the high reactivity of the hydroxyl radical. Phenolic compounds with multiple hydroxyl groups also exhibited high redox potential. Exploring the radical scavenging and reducing properties of antioxidants especially those which are found naturally in plant sources are of great interest due to their protective roles in biological systems.

  10. Free radical scavenging activity of Eagle tea and their flavonoids

    Directory of Open Access Journals (Sweden)

    Qiong Meng

    2012-06-01

    Full Text Available In this study, an online HPLC-DAD-MS coupled with 2,2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid diammonium salt (ABTS assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components. Twenty-three chromatographic peaks were detected, and nineteen components had free radical scavenging activity. Among them, eight compounds were identified as flavonoids (hyperin, isoquercitrin, quercitrin, quercetin, kaempferol, catechins, chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.

  11. A pulse radiolysis study of the OH radical induced autoxidation of methanesulfinic acid

    DEFF Research Database (Denmark)

    Sehested, K.; Holcman, J.

    1996-01-01

    Methanesulfinic acid, CH3SO2H, reacts with OH radicals at pH 7 forming CH3SO2 radicals with a rate constant k = (6.0 +/- 1.0) x 10(9) M(-1) s(-1). The CH3SO2 radical absorbs at 325 nm with an extinction coefficient of 900 +/- 100 M(-1) cm(-1) and disappears in a second order self-reaction with k...... = (1.0 +/- 0.2) x 10(9) M(-1) s(-1). This radical reacts with oxygen, k = (1.2 +/- 0.3) x 10(9) M(-1) s(-1), forming a peroxy radical which absorbs in the UV below 300 nm. The peroxy radical reacts in turn with methanesulfinic acid reforming the CH3SO2 radical whereby a chain oxidation of sulfinic acid...... takes place. During the course of the chain oxidation a peroxyacid, presumably methaneperoxymonosulfonic acid, is formed and accumulated. This acid absorbs in the UV and eventually decays by reaction with excess methanesulfinic acid k = 5 x 10(3) M(-1) s(-1). The final product of the chain autoxidation...

  12. Ginsenoside Rb1 directly scavenges hydroxyl radical and hypochlorous acid.

    Science.gov (United States)

    Lü, Jian-Ming; Weakley, Sarah M; Yang, Zhen; Hu, Ming; Yao, Qizhi; Chen, Changyi

    2012-01-01

    Reactive oxygen species (ROS) have been implicated in a variety of inflammatory diseases including cardiovascular disease (CVD), cancer, diabetes, Alzheimer's disease, autism, cataracts and aging. When endogenous mechanisms for the maintenance of redox homeostasis are overwhelmed, dietary intake of antioxidants contributes substantially to balancing the body's oxidant/antioxidant status. Ginsenosides are thought to be primarily responsible for the pharmacological effect of P. ginseng root extracts on oxidative stress and inflammation. However, little is known about the underlying antioxidant mechanisms of individual ginsenoside; specifically, the reactivity of ginsenoside Rb1 with ROS has not been well studied. We found that Rb1 can significantly and selectively reduce hydroxyl radical (●OH) and hypochlorous acid (HOCl), two of the strongest ROS, with unique molecular mechanisms in a cell-free system. Rb1 directly scavenges the ●OH and protects plasmid DNA from damage induced by ●OH. ●OH likely attacks the double bond on the side chain of Rb1 as well as hydrogen atoms adjacent to the -OH groups, including those of sugar moieties. Rb1 also shows a high reactivity to HOCl and effectively inhibits HOCl-induced tyrosine chlorination in a cell free system. HOCl is added to the double bond of Rb1; the -Cl group and -OH group of HOCl possibly bond at C-24 and C-25 of Rb1 based on the regioselectivity of Markovnikov's Rule. To our knowledge, this is the first demonstration that ginsenoside Rb1 scavenges HOCl and protects tyrosine from HOCl-induced chlorination. Thus, this study reveals unique antioxidant mechanisms of individual ginsenoside Rb1, which may contribute to the pharmacological effect of P. ginseng and to the development of effective strategies for clinical applications of ginsenosides.

  13. Phenylpropanoid acid esters from Korean propolis and their antioxidant activities.

    Science.gov (United States)

    Lee, In-Kyoung; Han, Myung-Suk; Kim, Dae-Won; Yun, Bong-Sik

    2014-08-01

    Ten phenylpropanoic acid esters were isolated from an ethanolic extract of Korean propolis. Their structures were elucidated by spectroscopic methods including NMR and ESI-MS. Caffeic acid esters with catechol moiety exhibited significant ABTS and DPPH radical scavenging activity and protective effect against DNA damage by a Fenton reaction.

  14. Evaluation of the antiradical properties of phenolic acids.

    Science.gov (United States)

    Koroleva, Olga; Torkova, Anna; Nikolaev, Ilya; Khrameeva, Ekaterina; Fedorova, Tatyana; Tsentalovich, Mikhail; Amarowicz, Ryszard

    2014-09-16

    Antioxidant capacity (AOC) against peroxyl radical and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation was measured for a series of p-hydroxybenzoic (HB) and p-hydroxycinnamic (HC) acids at different pH. Quantum-chemical computation was performed using Gaussian 3.0 software package to calculate the geometry and energy parameters of the same compounds. Significant correlations were revealed between AOC and a number of calculated parameters. The most significant AOC descriptors for the studied compounds against peroxyl radical were found to be HOMO energy, rigidity (η) and Mulliken charge on the carbon atom in m-position to the phenolic hydroxyl. The most significant descriptor of the antioxidant properties against the ABTS radical cation at рН 7.40 is electron transfer enthalpy from the phenolate ion. The mechanism of AOC realization has been proposed for HB and HC acids against both radicals.

  15. Evaluation of the Antiradical Properties of Phenolic Acids

    Directory of Open Access Journals (Sweden)

    Olga Koroleva

    2014-09-01

    Full Text Available Antioxidant capacity (AOC against peroxyl radical and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS radical cation was measured for a series of p-hydroxybenzoic (HB and p-hydroxycinnamic (HC acids at different pH. Quantum-chemical computation was performed using Gaussian 3.0 software package to calculate the geometry and energy parameters of the same compounds. Significant correlations were revealed between AOC and a number of calculated parameters. The most significant AOC descriptors for the studied compounds against peroxyl radical were found to be HOMO energy, rigidity (η and Mulliken charge on the carbon atom in m-position to the phenolic hydroxyl. The most significant descriptor of the antioxidant properties against the ABTS radical cation at рН 7.40 is electron transfer enthalpy from the phenolate ion. The mechanism of AOC realization has been proposed for HB and HC acids against both radicals.

  16. EFFECTS OF SOLVENT POLARITY ON FREE RADICAL COPOLY MERIZATION OF 5-HEXENOIC ACID AND ACRYLONITRILE

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; XIE Shishan; CAO Mengjiun

    1987-01-01

    The effects of solvent polarity on free radical copolymerization of 5-hexenoic acid and acrylonitrile at 60℃ were studied. It was observed that as the polarity of solvents enhanced, both the copolymerization rate and the reactivity ratios r1, r2 increased, while the alternating tendency of monomer units in copolymer chain decreased. It is believed that the solvent polarity raises the reactivities of acrylonitrile monomer and its growing chain radical, but causes no distinct variation in those of 5-hexenoic acid.

  17. Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

    Directory of Open Access Journals (Sweden)

    Takayuki Mokudai

    Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

  18. Measurement of antioxidant activity with trifluoperazine dihydrochloride radical cation

    Directory of Open Access Journals (Sweden)

    M.N. Asghar

    2008-06-01

    Full Text Available A novel, rapid and cost-effective trifluoperazine dihydrochloride (TFPH decolorization assay is described for the screening of antioxidant activity. A chromogenic reaction between TFPH and potassium persulfate at low pH produces an orange-red radical cation with maximum absorption at 502 nm in its first-order derivative spectrum. TFPH was dissolved in distilled water to give a 100 mM solution. The TFPH radical cation solution was made by reacting 0.5 mL of the solution with K2S2O8 (final concentration: 0.1 mM and diluting to 100 mL with 4 M H2SO4 solution. A linear inhibition of color production was observed with linearly increasing amounts of antioxidants, with correlation coefficients (R² ranging from 0.999 to 0.983. The antioxidant capacity of standard solutions of an antioxidant was evaluated by comparing with the inhibition curve using Trolox as the standard. Comparison of antioxidant capacity determined with this newly developed TFPH assay and with the well-known 2,2'-azinobis-[3-ethylbenzthiazoline-6-sulfonic acid] (ABTS-persulfate decolorization assay indicated the efficacy and sensitivity of the procedure. The proposed assay is less expensive (costs about US$4 per 100 assays and requires only 20 min for preparation of radical cation solution in comparison with ABTS assay, in which almost 12-16 h are required for preparation of a stable ABTS radical cation solution. The present assay has the advantage over ABTS assay that it can be used to measure the antioxidant activity of the samples, which are naturally found at a pH as low as 1, because the radical cation itself has been stabilized at low pH.

  19. Reactivity of hydroxybenzoic acid derivatives towards electrogenerated HO radicals

    OpenAIRE

    2013-01-01

    In the last decade there has been a lot of interest in the study of reactive oxygen species (ROS) and their role in many areas such as medicine, biology and chemistry. Among the ROS, HO radicals are the most reactive species and the extension of their reaction with organics can lead to the formation of CO2 thus the genera...

  20. Test for antioxidant ability by scavenging long-lived mutagenic radicals in mammalian cells and by blood test with intentional radicals: an application of gallic acid

    Science.gov (United States)

    Kumagai, Jun; Kawaura, Tomoko; Miyazaki, Tetsuo; Prost, Michel; Prost, Emmanuelle; Watanabe, Masami; Quetin-Leclercq, Joëlle

    2003-01-01

    Antioxidant ability of gallic acid (GA) are determined both by electron spin resonance measurement of long-lived radicals produced in γ-ray irradiated Syrian golden hamster embryo cells with GA and by hemolysis measurement with GA when blood cells are submitted to radicals. Scavenging properties of GA are determined by the reaction rate constant with long-lived mutagenic radicals in the cells while the blood test allows to analyze the global effects of this compound: radical scavenger+metal ion chelator+regeneration of intra- and extra-cellular antioxidant.

  1. OH-radical induced degradation of hydroxybenzoic- and hydroxycinnamic acids and formation of aromatic products-A gamma radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Krimmel, Birgit; Swoboda, Friederike [University of Vienna, Department of Nutritional Sciences, Section Radiation Biology (Austria); Solar, Sonja, E-mail: sonja.solar@univie.ac.a [University of Vienna, Department of Nutritional Sciences, Section Radiation Biology (Austria); Reznicek, Gottfried [Department of Pharmacognosy, Althanstrasse 14, A-1090 Vienna (Austria)

    2010-12-15

    The OH-radical induced degradation of hydroxybenzoic acids (HBA), hydroxycinnamic acids (HCiA) and methoxylated derivatives, as well as of chlorogenic acid and rosmarinic acid was studied by gamma radiolysis in aerated aqueous solutions. Primary aromatic products resulting from an OH-radical attachment to the ring (hydroxylation), to the position occupied by the methoxyl group (replacement -OCH{sub 3} by -OH) as well as to the propenoic acid side chain of the cinnamic acids (benzaldehyde formations) were analysed by HPLC-UV and LC-ESI-MS. A comparison of the extent of these processes is given for 3,4-dihydroxybenzoic acid, vanillic acid, isovanillic acid, syringic acid, cinnamic acid, 4-hydroxycinnamic acid, caffeic acid, ferulic acid, isoferulic acid, chlorogenic acid, and rosmarinic acid. For all cinnamic acids and derivatives benzaldehydes were significant oxidation products. With the release of caffeic acid from chlorogenic acid the cleavage of a phenolic glycoside could be demonstrated. Reaction mechanisms are discussed.

  2. OH-radical induced degradation of hydroxybenzoic- and hydroxycinnamic acids and formation of aromatic products—A gamma radiolysis study

    Science.gov (United States)

    Krimmel, Birgit; Swoboda, Friederike; Solar, Sonja; Reznicek, Gottfried

    2010-12-01

    The OH-radical induced degradation of hydroxybenzoic acids (HBA), hydroxycinnamic acids (HCiA) and methoxylated derivatives, as well as of chlorogenic acid and rosmarinic acid was studied by gamma radiolysis in aerated aqueous solutions. Primary aromatic products resulting from an OH-radical attachment to the ring (hydroxylation), to the position occupied by the methoxyl group (replacement -OCH 3 by -OH) as well as to the propenoic acid side chain of the cinnamic acids (benzaldehyde formations) were analysed by HPLC-UV and LC-ESI-MS. A comparison of the extent of these processes is given for 3,4-dihydroxybenzoic acid, vanillic acid, isovanillic acid, syringic acid, cinnamic acid, 4-hydroxycinnamic acid, caffeic acid, ferulic acid, isoferulic acid, chlorogenic acid, and rosmarinic acid. For all cinnamic acids and derivatives benzaldehydes were significant oxidation products. With the release of caffeic acid from chlorogenic acid the cleavage of a phenolic glycoside could be demonstrated. Reaction mechanisms are discussed.

  3. [Effects of ascorbic acid on the free radical formations of isoniazid and its metabolites].

    Science.gov (United States)

    Matsuki, Y; Akazawa, M; Tsuchiya, K; Sakurai, H; Kiwada, H; Goromaru, T

    1991-10-01

    By the use of electron spin resonance (ESR) spectroscopy and of spin-trapping technique, the effects of ascorbic acid on the formation of the free radical intermediates due to isoniazid (INAH) and its metabolites were investigated with a microsomal system. When alpha-(4-pyridyl 1-oxide)-N-tert butylnitrone (4-POBN) was used as a spin trapping agent, the ESR signal due to hydrazine (Hy) was formed to be most intensive among others. Therefore, it was presumed that Hy is a potent intermediate to cause an INAH-induced hepatic injury. In the presence of ascorbic acid (AA), the free radical formation of Hy, INAH and acetyl hydrazine was significantly inhibited, suggesting that AA may affect the INAH-hepatitis. By the addition of inhibitors of cytochrome P-450 like metyrapone and CO, the generation of the radical from Hy decreased, confirming that the radical is formed by the cytochrome P-450 dependent microsome systems. The 4-POBN-trapped radical species generated from Hy was presumed to be the hydrazyl radical by the results of mass spectrometry.

  4. Arachidonic acid modulates hippocampal calcium current via protein kinase C and oxygen radicals.

    Science.gov (United States)

    Keyser, D O; Alger, B E

    1990-10-01

    Arachidonic acid (AA) is a second messenger liberated via receptor activation of phospholipase A2 or diacylglycerol-lipase. We used whole-cell voltage clamp of acutely isolated hippocampal CA1 pyramidal cells to investigate the hypothesis that AA modulates Ca2+ channel current (ICa) via activation of protein kinase C (PKC) and generation of free radicals. AA depressed ICa in a dose- and time-dependent manner similar to that previously reported for the action of phorbol esters on ICa. A similar depression was seen with a xanthine-based free radical generating system. The specific PKC inhibitor PKCI (19-36), the protein kinase inhibitor H-7, and the superoxide free radical scavenger SOD each blocked ICa depression by 70%-80%. Complete block of the AA response occurred when SOD was used simultaneously with a PKC inhibitor. These data suggest that PKC and free radicals play a role in AA-induced suppression of ICa.

  5. Interaction between fulvic acids of different origins and active oxygen radicals

    Institute of Scientific and Technical Information of China (English)

    王春霞; 王子健; 彭安; 侯京武; 忻文娟

    1996-01-01

    Using the spin trapping technique, the interaction between fulvic acids (FAs) of different origins and the active oxygen radicals was studied. The active oxygen radicals under study included superoxide anion (O2 · -) produced by xanthine oxidase (XOD) and stimulated polymorphonuclear leukocytes (PMN) of human being and hydroxyl radical ( ·OH) produced from Fenton’s reaction. It has been found that the FAs from both Kaschin-Beck disease (KBD) region and non-KBD region can accelerate the production of ·OH and scavenge O2 ·- . FA from peat can scavenge both O2·- and ·OH. The results show that the behavior of KBD and non-KBD FAs differs clearly from peat FA. It has been concluded that the superoxidation damage of KBD induced by FA is mainly due to hydroxyl radical reaction initiated in biological system.

  6. Influence of different free radicals on scavenging potency of gallic acid.

    Science.gov (United States)

    Đorović, Jelena; Marković, Jasmina M Dimitrić; Stepanić, Višnja; Begović, Nebojša; Amić, Dragan; Marković, Zoran

    2014-07-01

    The M05-2X/6-311++G(d,p) and B3LYP-D2/6-311++G(d,p) models are used to evaluate scavenging potency of gallic acid. The hydrogen atom transfer (HAT), sequential proton loss electron transfer (SPLET), and single electron transfer followed by proton transfer (SET-PT) mechanisms of gallic acid with some radicals ((•)OO(-), (•)OH, and CH3OO(•)) were investigated using the corresponding thermodynamic quantities: bond dissociation enthalpy (BDE), ionization potential (IP), and proton affinity (PA). Namely, the ΔHBDE, ΔHIP, and ΔHPA values of the corresponding reactions in some solvents (water, DMSO, pentylethanoate, and benzene) are investigated using an implicit solvation model (SMD). An approach based on the reactions enthalpies related to the examined mechanisms is applied. This approach shows that a thermodynamically favored mechanism depends on the polarity of reaction media and properties of free radical reactive species. The most acidic 4-OH group of gallic acid is the active site for radical inactivation. The results of this investigation indicate that the SPLET mechanism can be a favored reaction pathway for all three radicals in all solvents, except for (•)OH in the aqueous solution. In water, gallic acid can inactivate (•)OH by the HAT mechanism.

  7. Biguanides sensitize leukemia cells to ABT-737-induced apoptosis by inhibiting mitochondrial electron transport

    Science.gov (United States)

    Velez, Juliana; Pan, Rongqing; Lee, Jason T.C.; Enciso, Leonardo; Suarez, Marta; Duque, Jorge Eduardo; Jaramillo, Daniel; Lopez, Catalina; Morales, Ludis; Bornmann, William; Konopleva, Marina; Krystal, Gerald; Andreeff, Michael; Samudio, Ismael

    2016-01-01

    Metformin displays antileukemic effects partly due to activation of AMPK and subsequent inhibition of mTOR signaling. Nevertheless, Metformin also inhibits mitochondrial electron transport at complex I in an AMPK-independent manner, Here we report that Metformin and rotenone inhibit mitochondrial electron transport and increase triglyceride levels in leukemia cell lines, suggesting impairment of fatty acid oxidation (FAO). We also report that, like other FAO inhibitors, both agents and the related biguanide, Phenformin, increase sensitivity to apoptosis induction by the bcl-2 inhibitor ABT-737 supporting the notion that electron transport antagonizes activation of the intrinsic apoptosis pathway in leukemia cells. Both biguanides and rotenone induce superoxide generation in leukemia cells, indicating that oxidative damage may sensitize toABT-737 induced apoptosis. In addition, we demonstrate that Metformin sensitizes leukemia cells to the oligomerization of Bak, suggesting that the observed synergy with ABT-737 is mediated, at least in part, by enhanced outer mitochondrial membrane permeabilization. Notably, Phenformin was at least 10-fold more potent than Metformin in abrogating electron transport and increasing sensitivity to ABT-737, suggesting that this agent may be better suited for targeting hematological malignancies. Taken together, our results suggest that inhibition of mitochondrial metabolism by Metformin or Phenformin is associated with increased leukemia cell susceptibility to induction of intrinsic apoptosis, and provide a rationale for clinical studies exploring the efficacy of combining biguanides with the orally bioavailable derivative of ABT-737, Venetoclax. PMID:27283492

  8. Scavenging of free-radical metabolites of aniline xenobiotics and drugs by amino acid derivatives: toxicological implications of radical-transfer reactions.

    Science.gov (United States)

    Michail, Karim; Baghdasarian, Argishti; Narwaley, Malyaj; Aljuhani, Naif; Siraki, Arno G

    2013-12-16

    We investigated a novel scavenging mechanism of arylamine free radicals by poly- and monoaminocarboxylates. Free radicals of arylamine xenobiotics and drugs did not react with oxygen in peroxidase-catalyzed reactions; however, they showed marked oxygen uptake in the presence of an aminocarboxylate. These free-radical intermediates were identified using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and electron paramagnetic resonance (EPR) spectrometry. Diethylenetriaminepentaacetic acid (DTPA), a polyaminocarboxylate, caused a concentration-dependent attenuation of N-centered radicals produced by the peroxidative metabolism of arylamines with the subsequent formation of secondary aliphatic carbon-centered radicals stemming from the cosubstrate molecule. Analogously, N,N-dimethylglycine (DMG) and N-methyliminodiacetate (MIDA), but not iminodiacetic acid (IDA), demonstrated a similar scavenging effect of arylamine-derived free radicals in a horseradish peroxidase/H2O2 system. Using human promyelocytic leukemia (HL-60) cell lysate as a model of human neutrophils, DTPA, MIDA, and DMG readily reduced anilinium cation radicals derived from the arylamines and gave rise to the corresponding carbon radicals. The rate of peroxidase-triggered polymerization of aniline was studied as a measure of nitrogen-radical scavenging. Although, IDA had no effect on the rate of aniline polymerization, this was almost nullified in the presence of DTPA and MIDA at half of the molar concentration of the aniline substrate, whereas a 20 molar excess of DMPO caused only a partial inhibition. Furthermore, the yield of formaldehyde, a specific reaction endproduct of the oxidation of aminocarboxylates by aniline free-radical metabolites, was quantitatively determined. Azobenzene, a specific reaction product of peroxidase-catalyzed free-radical dimerization of aniline, was fully abrogated in the presence of DTPA, as confirmed by GC/MS. Under aerobic conditions, a radical-transfer reaction

  9. Release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals.

    Science.gov (United States)

    Liu, Fobang; Lai, Senchao; Tong, Haijie; Lakey, Pascale S J; Shiraiwa, Manabu; Weller, Michael G; Pöschl, Ulrich; Kampf, Christopher J

    2017-03-01

    Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals.

  10. Cationic and radical intermediates in the acid photorelease from aryl sulfonates and phosphates.

    Science.gov (United States)

    Terpolilli, Marco; Merli, Daniele; Protti, Stefano; Dichiarante, Valentina; Fagnoni, Maurizio; Albini, Angelo

    2011-01-01

    The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (≈0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with phosphates and (mainly) radical with sulfonates.

  11. Synthesis, Characterization, and Evaluation of Radical Scavenging Ability of Ellagic Acid-Loaded Nanogels

    Directory of Open Access Journals (Sweden)

    Gautam Behl

    2011-01-01

    Full Text Available Ellagic acid (EA, a potential antioxidant phytochemical has low aqueous solubility and bioavailability. In this paper, encapsulation of ellagic acid has been carried out into the biodegradable disulfide crosslinked poly (ethylene glycol PEO-based nanogels synthesized via AGET (activator generated electron transfer ATRP (atom transfer radical polymerization, and their radical scavenging ability was evaluated. The encapsulation of the EA was carried out at two drug loading percentages, that is, 10 and 20 wt.% of the nanogels. 1,1-Diphenyl-2-picryldrazyl (DPPH assay was utilized in order to assess the radical scavenging ability of the ellagic acid-loaded nanogels. A drug-loading level of about 2.5 wt.% was achieved with encapsulation efficiency of about 25% at 10 wt.% of the EA w.r.t nanogels, which was found to increase to about 4.7 wt.% with decreased encapsulation efficiency of 23.5% as EA content was increased to 20wt.% of the nanogels. Ellagic acid loading was found to be accompanied with increase in the size of the nanogels from 144.6±39.52 nm for neat nanogels to 217.8±105.5 and 633±160.1 nm at 2.5 and 4.7 wt.% drug loading level. The nanogels were found to be capable of scavenging radicals and biocompatible on human cervical cancer cell lines (HeLa cells at appropriate concentrations.

  12. Atmospheric chemistry of perfluorinated carboxylic acids: Reaction with OH radicals and atmospheric lifetimes

    DEFF Research Database (Denmark)

    Hurley, MD; Andersen, Mads Peter Sulbæk; Wallington, TJ;

    2004-01-01

    Relative rate techniques were used to study the kinetics of the reactions of OH radicals with a homologous series of perfluorinated acids, F(CF2)(n)COOH (n = 1, 2, 3, 4), in 700 Torr of air at 296 +/- 2 K. For n > 1, the length of the F(CF2)(n) group had no discernible impact on the reactivity...

  13. Change of oxygen free radical metabolism and free amino acids of patients with hyperthyroidism

    Institute of Scientific and Technical Information of China (English)

    Hua-Ling Ruan; Li Zhao; Kun-Quan Guo; Kun Yang; Lin-Xiu Ye; Xue Sun

    2016-01-01

    Objective:To study the change situation of oxygen free radical metabolism and free amino acids of patients with hyperthyroidism.Methods:Eighty-one patients with hyperthyroidism who were treated in our hospital from May 2013 to October 2014 were selected as the observation group, while 81 healthy persons with health examination at the same period were the control group. Then, the serum oxygen free radical indexes and free amino acids of the two groups were respectively detected and compared, and the detection results of patients in the observation group with different etiologic types and basal metabolic rate were also compared. Results:The serum oxygen free radical related indexes of the observation group were all higher than those of the control group; the serum antioxidant related indexes were all lower than those of the control group; and the serum free amino acids levels were all obviously lower than those of the control group. Besides, the detection results of patients with severe hyperthyroidism in the observation group were worse than those of patients with mild and moderate disease, while the detection results of the observation group with different types of hyperthyroidism had no significant differences.Conclusions:The fluctuation of oxygen free radical metabolism and free amino acids of patients with hyperthyroidism are obvious, and the detection results of patients with different basal metabolic rates are also quite obvious.

  14. Enantioselective conjugate additions of α-amino radicals via cooperative photoredox and Lewis acid catalysis.

    Science.gov (United States)

    Ruiz Espelt, Laura; McPherson, Iain S; Wiensch, Eric M; Yoon, Tehshik P

    2015-02-25

    We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates.

  15. Sub-millitesla magnetic field effects on the recombination reaction of flavin and ascorbic acid radicals

    Science.gov (United States)

    Evans, Emrys W.; Kattnig, Daniel R.; Henbest, Kevin B.; Hore, P. J.; Mackenzie, Stuart R.; Timmel, Christiane R.

    2016-08-01

    Even though the interaction of a acid. Direct control of the reaction pathway is achieved by varying the rate of electron transfer from ascorbic acid to the photo-excited flavin. At pH 7.0, we verify the theoretical prediction that, apart from a sign change, the form of the magnetic field effect is independent of the initial spin configuration of the radical pair. The data agree well with model calculations based on a Green's function approach that allows multinuclear spin systems to be treated including the diffusive motion of the radicals, their spin-selective recombination reactions, and the effects of the inter-radical exchange interaction. The protonation states of the radicals are uniquely determined from the form of the magnetic field-dependence. At pH 3.0, the effects of two chemically distinct radical pair complexes combine to produce a pronounced response to ˜500 μT magnetic fields. These findings are relevant to the magnetic responses of cryptochromes (flavin-containing proteins proposed as magnetoreceptors in birds) and may aid the evaluation of effects of weak magnetic fields on other biologically relevant electron transfer processes.

  16. The B-cell lymphoma 2 (BCL2)-inhibitors, ABT-737 and ABT-263, are substrates for P-glycoprotein

    Energy Technology Data Exchange (ETDEWEB)

    Vogler, Meike, E-mail: mv62@le.ac.uk [MRC Toxicology Unit, University of Leicester, LE1 9HN Leicester (United Kingdom); Dickens, David, E-mail: David.Dickens@liverpool.ac.uk [Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, L69 3GL Liverpool (United Kingdom); Dyer, Martin J.S., E-mail: mjsd1@le.ac.uk [MRC Toxicology Unit, University of Leicester, LE1 9HN Leicester (United Kingdom); Owen, Andrew, E-mail: aowen@liverpool.ac.uk [Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, L69 3GL Liverpool (United Kingdom); Pirmohamed, Munir, E-mail: munirp@liv.ac.uk [Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, L69 3GL Liverpool (United Kingdom); Cohen, Gerald M., E-mail: gmc2@le.ac.uk [MRC Toxicology Unit, University of Leicester, LE1 9HN Leicester (United Kingdom)

    2011-05-06

    Highlights: {yields} The BCL2-inhibitor ABT-263 is a substrate for P-glycoprotein. {yields} Apoptosis is inhibited by P-glycoprotein expression. {yields} Overexpression of P-glycoprotein may contribute to resistance to ABT-263 or ABT-737. -- Abstract: Inhibition of BCL2 proteins is one of the most promising new approaches to targeted cancer therapy resulting in the induction of apoptosis. Amongst the most specific BCL2-inhibitors identified are ABT-737 and ABT-263. However, targeted therapy is often only effective for a limited amount of time because of the occurrence of drug resistance. In this study, the interaction of BCL2-inhibitors with the drug efflux transporter P-glycoprotein was investigated. Using {sup 3}H labelled ABT-263, we found that cells with high P-glycoprotein activity accumulated less drug. In addition, cells with increased P-glycoprotein expression were more resistant to apoptosis induced by either ABT-737 or ABT-263. Addition of tariquidar or verapamil sensitized the cells to BCL2-inhibitor treatment, resulting in higher apoptosis. Our data suggest that the BCL2-inhibitors ABT-737 and ABT-263 are substrates for P-glycoprotein. Over-expression of P-glycoprotein may be, at least partly, responsible for resistance to these BCL2-inhibitors.

  17. Electrochemical properties of tyrosine phenoxy and tryptophan indolyl radicals in peptides and amino acid analogues

    Energy Technology Data Exchange (ETDEWEB)

    DeFelippis, M.R.; Murthy, C.P.; Klapper, M.H. (Ohio State Univ., Columbus (United States)); Broitman, F.; Weinraub, D.; Faraggi, M. (Nuclear Research Centre-Negev, Beer Sheva (Israel))

    1991-04-18

    Reported here are the redox potentials of the tyrosine phenoxy (tyrO{sup {sm bullet}}) and tryptophan indolyl (trp{sup {sm bullet}}) radicals in peptides containing tyrosine or tryptophan residues. These were determined with pulse radiolysis, and the electrochemical techniques of cyclic voltammetry and differential pulse polarography. The pulse radiolytic and electrochemical methods yield comparable results. There are small differences (relative to the free amino acid) in redox potentials among the different tryptophan and tyrosine containing peptides; in the case of tryptophan these changes may correlate with the position of amino acid in the peptide. The authors also present the redox potentials of some tyrosine and tryptophan derivatives and the acid/base properties of the tryptophan radical cation, when both free and peptide bound.

  18. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal

    Directory of Open Access Journals (Sweden)

    Y. Tan

    2012-01-01

    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 μM–10 mM was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  19. Mechanism and kinetics in reactions of caffeic acid with radicals by pulse radiolysis and calculation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xifeng; Cai, Zhongli; Katsumura, Yosuke [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab

    2000-03-01

    The interaction of caffeic acid with e{sub aq}{sup -}, (CH{sub 3}){sub 2}(OH) CCH{sub 2}{sup {center_dot}}, CO{sub 2}{sup {center_dot}}{sup -}, H{sup {center_dot}}, {center_dot}OH and N{sub 3}{sup {center_dot}} radicals were studied by {gamma}-, pulse radiolysis and molecular orbital calculation. UV-visible spectra of electron/{center_dot}OH adducts, semi-quinone radicals of caffeic ions, and the stable products from the reactions were derived. The rate constants were determined. The attacked sites and the most favorable structures of the transient radicals were predicted. Reaction mechanisms were proposed. (author)

  20. Reactivity and acid-base behavior of ring-methoxylated arylalkanoic acid radical cations and radical zwitterions in aqueous solution. Influence of structural effects and pH on the benzylic C-H deprotonation pathway.

    Science.gov (United States)

    Bietti, Massimo; Capone, Alberto

    2006-07-07

    A product and time-resolved kinetic study of the one-electron oxidation of ring-methoxylated phenylpropanoic and phenylbutanoic acids (Ar(CH2)nCO2H, n = 2, 3) has been carried out at different pH values. Oxidation leads to the formation of aromatic radical cations (Ar.+(CH2)nCO2H) or radical zwitterions (Ar.+(CH2)nCO2-) depending on pH, and pKa values for the corresponding acid-base equilibria have been measured. In the radical cation, the acidity of the carboxylic proton decreases by increasing the number of methoxy ring substituents and by increasing the distance between the carboxylic group and the aromatic ring. At pH 1.7 or 6.7, the radical cations or radical zwitterions undergo benzylic C-H deprotonation as the exclusive side-chain fragmentation pathway, as clearly shown by product analysis results. At pH 1.7, the first-order deprotonation rate constants measured for the ring-methoxylated arylalkanoic acid radical cations are similar to those measured previously in acidic aqueous solution for the alpha-C-H deprotonation of structurally related ring-methoxylated alkylaromatic radical cations. In basic solution, the second-order rate constants for reaction of the radical zwitterions with (-)OH (k-OH)) have been obtained. These values are similar to those obtained previously for the (-)OH-induced alpha-C-H deprotonation of structurally related ring-methoxylated alkylaromatic radical cations, indicating that under these conditions the radical zwitterions undergo benzylic C-H deprotonation. Very interestingly, with 3,4-dimethoxyphenylethanoic acid radical zwitterion, that was previously observed to undergo exclusive decarboxylation up to pH 10, competition between decarboxylation and benzylic C-H deprotonation is observed above pH 11.

  1. Quantum Chemical Benchmarking, Validation, and Prediction of Acidity Constants for Substituted Pyridinium Ions and Pyridinyl Radicals.

    Science.gov (United States)

    Keith, John A; Carter, Emily A

    2012-09-11

    Sensibly modeling (photo)electrocatalytic reactions involving proton and electron transfer with computational quantum chemistry requires accurate descriptions of protonated, deprotonated, and radical species in solution. Procedures to do this are generally nontrivial, especially in cases that involve radical anions that are unstable in the gas phase. Recently, pyridinium and the corresponding reduced neutral radical have been postulated as key catalysts in the reduction of CO2 to methanol. To assess practical methodologies to describe the acid/base chemistry of these species, we employed density functional theory (DFT) in tandem with implicit solvation models to calculate acidity constants for 22 substituted pyridinium cations and their corresponding pyridinyl radicals in water solvent. We first benchmarked our calculations against experimental pyridinium deprotonation energies in both gas and aqueous phases. DFT with hybrid exchange-correlation functionals provide chemical accuracy for gas-phase data and allow absolute prediction of experimental pKas with unsigned errors under 1 pKa unit. The accuracy of this economical pKa calculation approach was further verified by benchmarking against highly accurate (but very expensive) CCSD(T)-F12 calculations. We compare the relative importance and sensitivity of these energies to selection of solvation model, solvation energy definitions, implicit solvation cavity definition, basis sets, electron densities, model geometries, and mixed implicit/explicit models. After determining the most accurate model to reproduce experimentally-known pKas from first principles, we apply the same approach to predict pKas for radical pyridinyl species that have been proposed relevant under electrochemical conditions. This work provides considerable insight into the pitfalls using continuum solvation models, particularly when used for radical species.

  2. A Comparative Study of the Radical-scavenging Activity of the Phenolcarboxylic Acids Caffeic Acid, p-Coumaric Acid, Chlorogenic Acid and Ferulic Acid, With or Without 2-Mercaptoethanol, a Thiol, Using the Induction Period Method

    Directory of Open Access Journals (Sweden)

    Seiichiro Fujisawa

    2008-10-01

    Full Text Available Phenolcarboxylic acid antioxidants do not act in vivo as radical-scavengers in isolation, but rather together with GSH (glutathione, a coantioxidant, they constitute an intricate antioxidant network. Caffeic acid, p-coumaric acid, ferulic acid and chlorogenic acid with or without 2-mercaptoethanol (ME, as a substitute for GSH, was investigated by the induction period (IP method for polymerization of methyl methacrylate (MMA initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN, a source of alkyl radicals, R. and benzoyl peroxide (BPO, a source of peroxy radicals, PhCOO. using differential scanning calorimetry (DSC. Upon PhCOO. radical scavenging, the stoichiometric factors (n, number of free radical trapped by one mole of antioxidant for caffeic acid, ferulic acid, p-coumaric acid and chlorogenic acid were 2.4, 1.8, 1.7 and 0.9, whereas upon R. radical scavenging, the corresponding values were 1.3, 1.2, 1.0 and 0.8, respectively. Antioxidants with n values close to 2 suggest the stepwise formation of semiquinone radicals and quinones. By contrast, those with n values close to 1 suggest the formation of dimers after single-electron oxidation, possibly due to recombination of corresponding aryloxy radicals. The ratio of the rate constant of inhibition to that of propagation (kinh/kp declined in the order chlorogenic acid > p-coumaric acid > ferulic acid > caffeic acid. The ratio of the observed IP for the phenolcarboxylic acid/2-mercapto-ethanol (ME mixture (1:1 molar ratio (A to the calculated IP (the simple sum of phenol acid antioxidant and ME (B was investigated. Upon R. scavenging, the caffeic acid or p-coumaric acid/ME mixture was A/B > 1, particularly the former was 1.2, suggesting a synergic effect. By contrast, upon PhCOO. scavenging, the corresponding mixture was A/B < 1, particularly the latter was 0.7, suggesting an antagonistic effect. Upon both radicals scavenging, the A/B for the ferulic acid or chlorogenic acid

  3. Evaluation of the free-radical-scavenging activity of diclofenac acid on the free-radical-induced haemolysis of human erythrocytes.

    Science.gov (United States)

    Tang, You-Zhi; Liu, Zai-Qun

    2006-05-01

    Free-radical-induced peroxidation in-vivo is regarded as the aetiology of some diseases and free-radical-scavenging drugs, also called antioxidants (AH), have been widely used to overcome oxidative stress. An in-vitro experimental method, 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced haemolysis of human erythrocytes can be applied to assess the free-radical-scavenging activity of a drug. The major objectives of this work were focused on three aspects. Firstly, introduction of the chemical kinetic deduction of free-radical-initiating reaction to AAPH-induced haemolysis of human erythrocytes, by which the number of free radicals trapped by an antioxidant, n, can be obtained after finding the quantitative relationship between the inhibition period (t(inh)) and the concentration of the antioxidant, t(inh) = (n/Ri) [AH]. Ri, the free-radical-initiating rate, was initially confirmed by using alpha-tocopherol (VE) whose n was taken as 2. Secondly, the free-radical-scavenging activity of diclofenac acid (DaH) and its sodium salt (DaNaH) was assessed. It has been found that DaH and DaNaH protect human erythrocytes against AAPH-induced haemolysis dose-dependently. In particular, the n values of DaH and DaNaH (4.96 and 3.60) were much higher than some traditional antioxidants, such as 6-hydroxyl-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox, a water-soluble structural analogue of VE, n = 0.30) and L-ascorbic acid (VC, n = 0.25), and L-ascorbyl-6-laurate (VC-12, a lipophilic structural analogue of VC, n = 1.11). Moreover, the free-radical-scavenging activity of lipophilic antioxidants is higher than the corresponding water-soluble species. Thirdly, the free-radical-scavenging activity of mixed antioxidants, VE + DaH, VC-12 + DaH, Trolox + DaNaH and VC + DaNaH, was revealed. The n value of VC, VC-12, VE and Trolox increase in the case of mixed usage with DaH and DaNaH, implying that diclofenac acid can repair the radical of these antioxidants. Thus, a mutual

  4. Performance and penetration of laccase and ABTS inks on various printing substrates.

    Science.gov (United States)

    Matilainen, Katriina; Hämäläinen, Tiina; Savolainen, Anne; Sipiläinen-Malm, Thea; Peltonen, Jouko; Erho, Tomi; Smolander, Maria

    2012-02-01

    Introduction of an enzyme and a colour-forming reagent into paper enables the development of an authenticity indicator. The purpose of this work was to study the performance of Trametes versicolor laccase, TvL, and ABTS, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt, in various printing substrates when printed with inkjet. The printing substrates included pre-coated mechanical paper additionally coated with PVA, silica and latex. The focus was on the bioanalytical performance and ink penetration. The setting of the printed TvL and ABTS ink was studied visually, with optical and confocal microscopy and with a so-called tape laminating technique. Technical properties of the printing substrates and effect of the surface chemistry were discussed and related to the bioanalytical properties. TvL activity persisted well during the printing. The best colour response was attained using the PVA-coated base paper. The film-forming ability of the PVA was found to be the main contributor to the colour reaction. The uniform, dense and non-porous PVA layer retains the ABTS and TVL molecules on top of the printing substrate. The high local ink concentration on the PVA coating layer combined with the absorptive paper substrate suggests that the PVA film acts as a filtering layer which retains TvL and ABTS molecules in the coating layer but allows most of the ink solvents to penetrate into the paper structure. TvL and ABTS molecules are also trapped in the PVA polymer network due to swelling effect of water. Electrostatic attractions between the PVA and ABTS and TvL molecules do not contribute to the colour reaction.

  5. Radical scavenging ability of gallic acid toward OH and OOH radicals. Reaction mechanism and rate constants from the density functional theory.

    Science.gov (United States)

    Marino, Tiziana; Galano, Annia; Russo, Nino

    2014-09-04

    Gallic acid is a ubiquitous compound, widely distributed in the vegetal kingdom and frequently found in the human diet. In the present work, its primary antioxidant activity has been investigated using the density functional theory (DFT), and the quantum mechanics-based test for overall free radical scavenging activity (QM-ORSA) protocol. It was found that gallic acid is a better antioxidant than the reference compound, Trolox, regardless of the polarity of the environment. In addition, gallic acid is predicted to be among the best peroxyl radical scavengers identified so far in nonpolar (lipid) media. This compound is capable of scavenging hydroxyl radicals at diffusion-limited rates, and hydroperoxyl radicals with rate constants in the order of 10(5) M(-1) s(-1). The deprotonation of gallic acid, in aqueous solution, is predicted to increase the protective action of this compound against oxidative stress. Gallic acid was also identified as a versatile scavenger, capable of rapidly deactivating a wide variety of reactive oxygen species (ROS) and reactive nitrogen species (RNS) via electron transfer at physiological pH.

  6. A comparative study of the radical-scavenging activity of the phenolcarboxylic acids caffeic acid, p-coumaric acid, chlorogenic acid and ferulic acid, with or without 2-mercaptoethanol, a thiol, using the induction period method.

    Science.gov (United States)

    Kadoma, Yoshinori; Fujisawa, Seiichiro

    2008-10-15

    Phenolcarboxylic acid antioxidants do not act in vivo as radical-scavengers in isolation, but rather together with GSH (glutathione), a coantioxidant, they constitute an intricate antioxidant network. Caffeic acid, p-coumaric acid, ferulic acid and chlorogenic acid with or without 2-mercaptoethanol (ME), as a substitute for GSH, was investigated by the induction period (IP) method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN, a source of alkyl radicals, R(.)) and benzoyl peroxide (BPO, a source of peroxy radicals, PhCOO(.)) using differential scanning calorimetry (DSC). Upon PhCOO(. )radical scavenging, the stoichiometric factors (n, number of free radical trapped by one mole of antioxidant) for caffeic acid, ferulic acid, p-coumaric acid and chlorogenic acid were 2.4, 1.8, 1.7 and 0.9, whereas upon R(.) radical scavenging, the corresponding values were 1.3, 1.2, 1.0 and 0.8, respectively. Antioxidants with n values close to 2 suggest the stepwise formation of semiquinone radicals and quinones. By contrast, those with n values close to 1 suggest the formation of dimers after single-electron oxidation, possibly due to recombination of corresponding aryloxy radicals. The ratio of the rate constant of inhibition to that of propagation (k(inh)/k(p)) declined in the order chlorogenic acid > p-coumaric acid > ferulic acid > caffeic acid. The ratio of the observed IP for the phenolcarboxylic acid/2-mercapto-ethanol (ME) mixture (1:1 molar ratio) (A) to the calculated IP (the simple sum of phenol acid antioxidant and ME) (B) was investigated. Upon R(.) scavenging, the caffeic acid or p-coumaric acid/ME mixture was A/B > 1, particularly the former was 1.2, suggesting a synergic effect. By contrast, upon PhCOO(.) scavenging, the corresponding mixture was A/B acid or chlorogenic acid/ME mixture was approximately 1. The reported beneficial antioxidant, anti-inflammatory and anticancer effects of caffeic

  7. Electron Paramagnetic Resonance Examination of Free Radical Formation in Salicylic Acid and Urea Exposed to UV Irradiation

    Directory of Open Access Journals (Sweden)

    Paweł Ramos

    2016-01-01

    Full Text Available Free radicals formed by UV irradiation of the two magistral formulas applied on the skin, salicylic acid and urea, were examined by X-band (9.3 GHz EPR spectroscopy. The influence of the time of UVA (315–400 nm irradiation on free radical properties and concentrations in the drug samples was determined. The nonirradiated magistral formula did not contain free radicals. Amplitudes (A and linewidths (ΔBpp of EPR spectra were analysed. Fast spin-lattice relaxation process existed in the tested drugs. UV irradiation did not change spin-lattice interactions in the tested magistral formula. Concentrations of free radicals formed by UV irradiation in salicylic acid and urea were ~1017–1018 spins/g. The strongest formation of free radicals under UV irradiation was observed for salicylic acid than for urea. Free radical concentration in salicylic acid increased with the increase of UV irradiation time from 15 minutes to 30 minutes, and after its value remained unchanged. The increase of free radical concentration in urea with UV irradiation time was stated. Salicylic acid is characterized with higher photosensitivity than urea. Salicylic acid, urea, and the skin treated by them should not be stored on UV exposure. The usefulness of EPR spectroscopy to optimize storage conditions of recipe drugs was conformed.

  8. Comparison of a novel extraction-based colorimetric (ABTS) method with membrane introduction mass spectrometry (MIMS): trichloramine dynamics in pool water.

    Science.gov (United States)

    Soltermann, Fabian; Widler, Tobias; Canonica, Silvio; von Gunten, Urs

    2014-07-01

    Trichloramine is a hazardous disinfection by-product, which is present in chlorinated swimming pools. Although it is primarily taken up by inhalation, the concentration in pool water is important to monitor pool water quality and to assess trichloramine mitigation strategies. To date, scarce data is available on trichloramine concentration in pool water due to the lack of a suitable and easily applicable analytical method. This study presents a novel low cost, colorimetric method which is easy to operate and suitable for on-site measurements of trichloramine concentrations ≥0.05 μM (≥0.01 mg L(-1) as Cl2). The analytical method (termed "extraction-based ABTS method") consists of, (i) trichloramine stripping from pool water samples, (ii) passing it through a solid phase filter, composed of silica gel impregnated with sulfamic acid to eliminate interferences and (iii) trichloramine reaction with the indicator 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to produce the coloured ABTS(•-) radical, which is measured at λ = 405 nm to determine the trichloramine concentration in the pool water sample. A comparison of the extraction-based ABTS method with membrane introduction mass spectrometry (MIMS) for 28 pool samples revealed a good correlation of the two methods. The trichloramine concentration in pool samples is correlated to HOCl, which is the most important factor for its formation. Other parameters such as combined chlorine and pH play a minor role while no correlation between trichloramine and the urea or the TOC concentration was observed. On-site measurements with MIMS in a wading pool over 6 days with a time resolution of 1 h confirmed that trichloramine concentrations strongly responded to changes in free chlorine concentrations. A diurnal measurement of trichloramine with a time resolution of 20 min revealed that trichloramine concentrations reacted quickly and sensitively to the bather load and that urea is

  9. Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution.

    Science.gov (United States)

    Liu, Chao; Wang, Xiaoqing; Li, Zhaodong; Cui, Lei; Li, Chaozhong

    2015-08-12

    We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH3CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation.

  10. A Comparative Study of the Radical-scavenging Activity of the Phenolcarboxylic Acids Caffeic Acid, p-Coumaric Acid, Chlorogenic Acid and Ferulic Acid, With or Without 2-Mercaptoethanol, a Thiol, Using the Induction Period Method

    OpenAIRE

    Seiichiro Fujisawa; Yoshinori Kadoma

    2008-01-01

    Phenolcarboxylic acid antioxidants do not act in vivo as radical-scavengers in isolation, but rather together with GSH (glutathione), a coantioxidant, they constitute an intricate antioxidant network. Caffeic acid, p-coumaric acid, ferulic acid and chlorogenic acid with or without 2-mercaptoethanol (ME), as a substitute for GSH, was investigated by the induction period (IP) method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile...

  11. Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid.

    Science.gov (United States)

    Boatright, William L

    2016-04-01

    The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc(-)) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5 μM from 100 μM ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc(-) was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2 mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2 mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8 mM or above.

  12. Radical formation of amino acid precursors in interstellar regions? Ser, Cys and Asp.

    Science.gov (United States)

    Knowles, Daniel J; Wang, Tianfang; Bowie, John H

    2010-11-07

    It is proposed that the glycine precursor NH(2)CH(2)CN may be synthesised in interstellar dust clouds by the radical combination reactions NH(2)˙ + ˙CH(2)CN → NH(2)CH(2)CN (ΔG = -302 kJ mol(-1)) and/or NH(2)CH(2)˙ + ˙CN → NH(2)CH(2)CN (ΔG = -414 kJ mol(-1)). All calculations at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31+G(d) level of theory. This paper extends that concept to radical/radical coupling reactions to form Ser, Cys and Asp precursor nitriles. The hydrogen abstraction process NH(2)CH(2)CN + HO˙→ NH(2)˙CHCN + H(2)O (ΔG = -130 kJ mol(-1)) is suggested to precede the radical coupling reactions NH(2)˙CHCN + R˙→ NH(2)CHRCN (R˙ = ˙CH(2)OH, ˙CH(2)SH and ˙CH(2)CN) to form nitrile precursors of the amino acids Ser, Cys and Asp. These three reactions are all favourable (ΔG = -240, -227 and -223 kJ mol(-1)). The radical species ˙CH(2)NH(2), ˙CH(2)OH, ˙CH(2)SH and ˙CH(2)CN are shown to be stable for the microsecond timeframe by a combination of theoretical calculations and the experimental mass spectrometric neutralization/reionization procedure.

  13. In vitro Free Radical Scavenging Potential of Defatted Ethanolic Extract of the Seeds of Lepidium sativum Linn.

    Institute of Scientific and Technical Information of China (English)

    Annie Shirwaikar; Bharatkumar Patel; Yogesh Kamariya; Vinit Parmar; Saleemulla Khan

    2011-01-01

    AIM:The objective of the present study was to evaluate the antioxidant potential of the defatted ethanolic extract of the seeds of Lepidium Sativum Linn.METHODS:Different in vitro chemical assays viz.DPPH (1,l-diphenyl-2-picrylhydrazyl) radical scavenging,ABTS (2,2-azinobis- (3-ethylbenzothiazoline-6-sulphonate) radical scavenging,iron chelation,lipid peroxidation,superoxide scavenging and non-enzymatic haemoglobin glycosylation assay were used.The total antioxidant capacity of the extract was determined spectrophotometrically by phosphomolybdic acid method.RESULT & CONCLUSION:The defatted lepidium seed extract showed significant free radical scavenging activity in ABTS and non-enzymatic glycosylation assays,and a moderate activity in all the other assays.IC5o of the extract in the DPPH,ABTS,iron chelation,lipid peroxidation and super oxide scavenging assays were found to be 171.13,38.64,128.94,71.39 and 206.09 μg.mL-1 respectively.The haemoglobin glycosylation assay of the extract showed a percentage scavenging of 46.60% and 74.88%,at 0.5 and 1.0 μg.mL-1,concentrations,respectively.Total antioxidant capacity of ethanolic extract of L.sativum (10 mg·mL-1) was found to be equivalent to 58.38 μg.mL-1 of ascorbic acid.

  14. Breaking the dogma: PCB-derived semiquinone free radicals do not form covalent adducts with DNA, GSH, and amino acids.

    Science.gov (United States)

    Wangpradit, Orarat; Rahaman, Asif; Mariappan, S V Santhana; Buettner, Garry R; Robertson, Larry W; Luthe, Gregor

    2016-02-01

    Covalent bond formations of free radical metabolites with biomolecules like DNA and proteins are thought to constitute a major mechanism of toxicity and carcinogenesis. Glutathione (GSH) is generally accepted as a radical scavenger protecting the cell. In the present study, we investigated a semiquinone radical (SQ(●-)) metabolite of the semivolatile 4-chlorobiphenyl, using electron paramagnetic resonance spectroscopy, and oxygen consumption. Proton nuclear magnetic resonance ((1)H NMR) and liquid chromatography-mass spectrometry (LC-MS) were also employed to elucidate the radical interaction with DNA, amino acids, and GSH. We found that DNA and oligonucleotides stabilized SQ(●-) by electron delocalization in the π-stacking system, resulting in persistent radical intercalated, rather than forming a covalent bond with SQ(●-). This finding was strongly supported by the semiempirical calculation of the semioccupied molecular orbital and the linear combination of the atomic orbitals, indicating 9.8 kcal mol(-1) energy gain. The insertion of SQ(●-) into the DNA strand may result in DNA strand breaks and interruption of DNA replication process or even activate radical mediated secondary reactions. The presence of amino acids resulted in a decrease of the electron paramagnetic resonance (EPR) signal of SQ(●-) and correlated with their isoelectric points. The pH shifts the equilibrium of the dianions of hydroquinone and influenced indirectly the formation of SQ(●-). Similar findings were observed with GSH and Cys. GSH and Cys functioned as indirect radical scavengers; their activities depend on their chemical equilibria with the corresponding quinones, and their further reaction via Michael addition. The generally accepted role of GSH as radical scavenger in biological systems should be reconsidered based upon these findings, questioning the generally accepted view of radical interaction of semiquinones with biologically active compounds, like DNA, amino acids

  15. Aqueous phototransformation of bisphenol S: the competitive radical-attack pathway to p-hydroxybenzenesulfonic acid.

    Science.gov (United States)

    Wang, Xiaowen; Ma, Jiahai; Wang, Zhenpeng; Guo, Rongrong; Hu, Xuefeng

    2014-01-01

    The kinetics, environmental influencing factors, products and reaction mechanism of aqueous phototransformation of bisphenol S (BPS), as an alternative to bisphenol A, which is of environmental concern, were investigated. p-Hydroxybenzenesulfonic acid, as the major transformation product was confirmed by gas chromatography - mass spectrometry, electrospray ionization, ¹H nuclear magnetic resonance and fluorescence spectrum analysis. A reaction pathway was proposed based on the reactive oxygen species related results by electron paramagnetic resonance and radical traps. The competition of the excited state of BPS between transferring electron to O₂ to •O₂(-) and directly oxidizing H₂O to •OH was revealed.

  16. ABT-737 synergizes with Bortezomib to kill melanoma cells

    Directory of Open Access Journals (Sweden)

    Steven N. Reuland

    2012-02-01

    The BH3 mimetic ABT-737 is a potent inhibitor of the anti-apoptotic proteins Bcl-2, Bcl-XL, and Bcl-w. The Bcl-2 family modulates sensitivity to anticancer drugs in many cancers, including melanomas. In this study, we examined whether ABT-737 is effective in killing melanoma cells either alone or in combination with a proteasome inhibitor already in clinical use (Bortezomib in vitro and in vivo, and further evaluated the mechanisms of action. Results showed that ABT-737 alone induced modest cytotoxicity in melanoma cells, but only at higher doses. Knock-down of the anti-apoptotic proteins Bcl-2, Bcl-XL, or Mcl-1 with siRNAs demonstrated that Mcl-1 is the critical mediator of melanoma's resistance to ABT-737 treatment. However, ABT-737 displayed strong synergistic lethality when combined with Bortezomib. Immunoblot analyses demonstrated that Bortezomib increased expression of Noxa, a pro-apoptotic Bcl-2 member that antagonizes Mcl-1. Additionally, siRNA-mediated inhibition of Noxa expression protected melanoma cells from cytotoxicity induced by the combination treatment. These results demonstrate that Bortezomib synergizes with ABT-737 by neutralizing Mcl-1's function via increased levels of Noxa. In a xenograft mouse model, although drug doses were limited due to toxicity, ABT-737 or Bortezomib slowed melanoma tumor growth compared to the control, and the drug combination significantly decreased growth compared to either drug alone. These data imply that less toxic drugs fulfilling a function similar to Bortezomib to neutralize Mcl-1 are promising candidates for combination with ABT-737 for treating melanomas.

  17. 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

  18. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    Directory of Open Access Journals (Sweden)

    M. Mendez

    2013-06-01

    Full Text Available The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  19. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and product identification

    Science.gov (United States)

    Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

    2013-12-01

    The heterogeneous reaction of Cl• radicals with submicron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapours and introduced into the reactor, where chlorine atoms were produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ) has been determined from the rate loss of PA measured by gas chromatography-mass spectrometer (GC/MS) analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analysis has shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2, which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids were identified by GC/MS. The formation of alcohols and monocarboxylic acids is also suspected. A reaction pathway for the main products and more functionalized species is proposed. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface but also in bulk by mechanisms which are still unclear. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  20. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    Science.gov (United States)

    Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

    2013-06-01

    The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ) has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  1. Isolation and characterisation of in vitro and cellular free radical scavenging peptides from corn peptide fractions.

    Science.gov (United States)

    Wang, Liying; Ding, Long; Wang, Ying; Zhang, Yan; Liu, Jingbo

    2015-02-16

    Corn gluten meal, a corn processing industry by-product, is a good source for the preparation of bioactive peptides due to its special amino acid composition. In the present study, the in vitro and cellular free radical scavenging activities of corn peptide fractions (CPFs) were investigated. Results indicated that CPF1 (molecular weight less than 1 kDa) and CPF2 (molecular weight between 1 and 3 kDa) exhibited good hydroxyl radical, superoxide anion radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Meanwhile, the in vitro radical scavenging activity of CPF1 was slightly higher than that of CPF2. Both CPF1 and CPF2 also exhibited significant cytoprotective effects and intracellular reactive oxygen species scavenging activity in Caco-2 cells exposed to hydrogen peroxide (H2O2). The amino acid composition analysis revealed that the CPF were rich in hydrophobic amino acids, which comprised of more than 45% of total amino acids. An antioxidant peptide sequence of Tyr-Phe-Cys-Leu-Thr (YFCLT) was identified from CPF1 using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI TOF/TOF MS). The YFCLT exhibited excellent ABTS radical scavenging activity with a 50% effective concentration (EC50) value of 37.63 µM, which was much lower than that of Trolox. In conclusion, corn gluten meal might be a good source to prepare antioxidant peptides.

  2. On the reaction of lupulones, hops β-acids, with 1-hydroxyethyl radical.

    Science.gov (United States)

    de Almeida, Natália E C; do Nascimento, Eduardo S P; Cardoso, Daniel R

    2012-10-24

    Lupulones, hops β-acids, are one of the main constituents of the hops resin and have an important contribution to the overall bacteriostatic activity of hops during beer brewing. The use of lupulones as natural alternatives to antibiotics is increasing in the food industry and also in bioethanol production. However, lupulones are easy oxidizable and have been shown to be very reactive toward 1-hydroxyethyl radical with apparent bimolecular rate constants close to diffusion control k = 2.9 × 10(8) and 2.6 × 10(8) L mol(-1) s(-1) at 25.0 ± 0.2 °C in ethanol-water solution (10% of ethanol (v/v)) as probed by EPR and ESI-IT-MS/MS spin-trapping competitive kinetics, respectively. The free energy change for an electron-transfer mechanism is ΔG° = 106 kJ/mol as calculated from the oxidation peak potential experimentally determined for lupulones (1.1 V vs NHE) by cyclic voltammetry and the reported reduction potential for 1-hydroxyethyl radical. The major reaction products identified by LC-ESI-IT-MS/MS and ultrahigh-resolution accurate mass spectrometry (orbitrap FT-MS) are hydroxylated lupulone derivatives and 1-hydroxyethyl radical adducts. The lack of pH dependence for the reaction rate constant, the calculated free energy change for electron transfer, and the main reaction products strongly suggest the prenyl side chains at the hops β-acids as the reaction centers rather than the β,β'-triketone moiety.

  3. Effect of UV Irradiation and Temperature on Free Radical Properties in Dehydrocholic and Ursodeoxycholic Acids: An EPR Study

    Directory of Open Access Journals (Sweden)

    Małgorzata Dołowy

    2014-01-01

    Full Text Available The effect of UV irradiation and temperature on the formation and properties of free radicals in two pharmaceutical important bile acids, such as dehydrocholic (DH and ursodeoxycholic acids (UDC, was examined. Electron paramagnetic resonance (EPR spectroscopy was applied to determine the paramagnetic character of UV irradiated and thermally sterilized drugs. Thermal and UV irradiation sterilizations of both compounds were carried out at different conditions according to pharmaceutical norms. The performed EPR measurements of UV irradiated and thermally sterilized DH and UDC samples proved the existence of the complex free radical systems in examined bile acids. Significant influence of UV irradiation in comparison with applied thermal sterilization on free radical concentrations in DH and UDC samples was observed. The results pointed out that thermal method is most suitable for bile acid sterilization. Therefore, this kind of sterilization should be applied in practice.

  4. Hydrogen bonding in the hydroxysulfinyl radical-formic acid-water system: A theoretical study.

    Science.gov (United States)

    Tušar, Simona; Lesar, Antonija

    2016-06-30

    Quantum chemical methods have been employed to evaluate the possible configurations of the 1:1 and 1:2 HOSO-formic acid complexes and 1:1:1 HOSO-formic acid-water complexes. The first type of complex involves two H bonds, while the other two types comprise three H bonds in a ring. The complexes are relatively stable, with CBS-QB3 computed binding energies of 14.3 kcal mol(-1) , 23.4 kcal mol(-1) , and 21.1 kcal mol(-1) for the lowest-energy structures of the 1:1, 1:2, and 1:1:1 complexes, respectively. Complex formations induce a large spectral red-shift and an enhancement of the IR intensity for the H-bonded OH stretching modes relative to those in the parent monomers. TDDFT calculations of the low-lying electronic excited states demonstrate that the complexes are photochemically quite stable in the troposphere. Small spectral shifts in comparison to the free HOSO radical suggest that the radical and the complexes would not be easily distinguishable using standard UV/vis absorption spectroscopy. © 2016 Wiley Periodicals, Inc.

  5. Histone H1- and other protein- and amino acid-hydroperoxides can give rise to free radicals which oxidize DNA

    DEFF Research Database (Denmark)

    Luxford, C; Morin, B; Dean, R T

    1999-01-01

    analysis has demonstrated that radicals from histone H1-hydroperoxides, and other protein and amino acid hydroperoxides, can also oxidize both free 2'-deoxyguanosine and intact calf thymus DNA to give the mutagenic oxidized base 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-hydroxy-2'-deoxyguanosine, 8-oxod......Exposure of amino acids, peptides and proteins to radicals, in the presence of oxygen, gives high yields of hydroperoxides. These materials are readily decomposed by transition metal ions to give further radicals. We hypothesized that hydroperoxide formation on nuclear proteins, and subsequent...... decomposition of these hydroperoxides to radicals, might result in oxidative damage to associated DNA. We demonstrate here that exposure of histone H1 and model compounds to gamma-radiation in the presence of oxygen gives hydroperoxides in a dose-dependent manner. These hydroperoxides decompose to oxygen...

  6. A Perspective on Free Radical Autoxidation: The Physical Organic Chemistry of Polyunsaturated Fatty Acid and Sterol Peroxidation

    Science.gov (United States)

    2013-01-01

    This Perspective describes advances from the author’s laboratory on the free radical reactions of organic compounds with molecular oxygen. Polyunsaturated fatty acids (PUFAs) and sterols are particularly prone to undergo radical chain oxidation and evidence suggests that this process, known as lipid peroxidation, occurs in vivo under a variety of conditions that are the result of an oxidative stress. Cyclic peroxides, hydroperoxides, and epoxy-alcohols are major products formed from peroxidation and the basic mechanisms of product formation are now reasonably well understood. These mechanisms include reversible addition of oxygen to carbon radicals, rearrangement and cyclization of allyl and pentadienyl peroxyl radicals and homolytic substitution of carbon radicals on the peroxide bond. A physical organic approach to the problem of free radicals in biology and medicine is highlighted in this Perspective with stereochemical, kinetic and extrathermodynamic probes applied to the study of mechanism. A radical clock permits the determination of free radical propagation rate constants and 7-dehydrocholesterol, the immediate biosynthetic precursor of cholesterol, is found by this clock to be one of the most oxidizable lipids known. The consequences of the extreme reactivity of 7-dehydrocholesterol on human health is the focus of a current research theme in the author’s laboratory. PMID:23445181

  7. A perspective on free radical autoxidation: the physical organic chemistry of polyunsaturated fatty acid and sterol peroxidation.

    Science.gov (United States)

    Porter, Ned A

    2013-04-19

    This Perspective describes advances from the author's laboratory on the free radical reactions of organic compounds with molecular oxygen. Polyunsaturated fatty acids (PUFAs) and sterols are particularly prone to undergo radical chain oxidation, and evidence suggests that this process, known as lipid peroxidation, occurs in vivo under a variety of conditions that are the result of an oxidative stress. Cyclic peroxides, hydroperoxides, and epoxy alcohols are major products formed from peroxidation, and the basic mechanisms of product formation are now reasonably well understood. These mechanisms include reversible addition of oxygen to carbon radicals, rearrangement and cyclization of allyl and pentadienyl peroxyl radicals, and homolytic substitution of carbon radicals on the peroxide bond. A physical organic approach to the problem of free radicals in biology and medicine is highlighted in this Perspective with stereochemical, kinetic, and extrathermodynamic probes applied to the study of mechanism. A radical clock permits the determination of free radical propagation rate constants, and 7-dehydrocholesterol, the immediate biosynthetic precursor of cholesterol, is found by this clock to be one of the most oxidizable lipids known. The consequences of the extreme reactivity of 7-dehydrocholesterol on human health is the focus of a current research theme in the author's laboratory.

  8. A Perspective on Free Radical Autoxidation: The Physical Organic Chemistry of Polyunsaturated Fatty Acid and Sterol Peroxidation

    OpenAIRE

    2013-01-01

    This Perspective describes advances from the author’s laboratory on the free radical reactions of organic compounds with molecular oxygen. Polyunsaturated fatty acids (PUFAs) and sterols are particularly prone to undergo radical chain oxidation and evidence suggests that this process, known as lipid peroxidation, occurs in vivo under a variety of conditions that are the result of an oxidative stress. Cyclic peroxides, hydroperoxides, and epoxy-alcohols are major products formed from peroxidat...

  9. Characterization of fatty acids, bioactive lipids, and radical scavenging activity of Canterbury bells seed oil

    Directory of Open Access Journals (Sweden)

    Hassanien, M. F.R.

    2014-06-01

    Full Text Available The aim of this study was to characterize the chemical composition and radical scavenging activity of Canterbury bells (Campanula medium seed oil. C. medium seeds contained 9.2% extractable oil. The lipid classes, fatty acids, phytosterol and tocopherol composition of C. medium seed oil were determined. The amount of neutral lipids in the oil was the highest, followed by glycolipids and phospholipids. Linoleic and oleic were the main fatty acids. C. medium oil is characterized by high levels of phytosterols and β-sitosterol was the main compound. β-Tocopherol constituted 42.5% of the total tocopherol content followed by γ-tocopherol. The radical scavenging activity (RSA toward 1,1-diphenyl-2-picrylhydrazyl (DPPH radicals and galvinoxyl radicals of C. medium oil were higher than those of extra virgin olive oil. The diverse potential uses of C. medium oil may make this plant industrially important.El objetivo de este estudio fue caracterizar la composición química y la actividad de captación de radicales de aceites de semillas de campanillas de Canterbury (Campanula medium. Las semillas de C. medium contenían 9,2 % de aceite extraíble. Se determinó la composición de las diferentes clases de lípidos, ácidos grasos, fitoesteroles y tocoferoles. La cantidad de lípidos neutros en el aceite fue mayoritario, seguido de glicolípidos y fosfolípidos. Linoleico y oleico fueron los ácidos grasos principales. El aceite de C. medium se caracteriza por altos niveles de fitoesteroles y β-sitosterol fue el compuesto principal. β-tocoferol constituía 42,5 % del contenido total de tocoferol seguido de γ-tocoferol. La actividad de captación de radicales (RSA a 1,1-difenil-2- picrilhidrazil (DPPH y radicales galvinoxil de C. medium fueron superiores a las de aceite de oliva virgen extra. Los diversos usos potenciales de los aceites de C. medium pueden hacer que esta planta pueda ser importante industrialmente.

  10. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid

    Directory of Open Access Journals (Sweden)

    Y. Tan

    2011-06-01

    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid is an important intermediate in aqueous methylglyoxal oxidation and a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. Altieri et al. (2008 proposed that acetic acid was the precursor of oligoesters observed in methylglyoxal oxidation. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid at concentrations relevant to atmospheric waters (20 μM–10 mM was oxidized by OH radical. Products were analyzed by ion chromatography (IC, electrospray ionization mass spectrometry (ESI-MS, and IC-ESI-MS. The formation of glyoxylic, glycolic, and oxalic acids were observed. In contrast to methylglyoxal oxidation, succinic acid and oligomers were not detected. Using results from these and methylglyoxal + OH radical experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  11. Phytic acid suppresses ischemia-induced hydroxyl radical generation in rat myocardium.

    Science.gov (United States)

    Obata, Toshio; Nakashima, Michiko

    2016-03-05

    The present study examined whether ischemia-reperfusion-induced hydroxyl radical (·OH) generation was attenuated by myo-inositol hexaphosphoric acid (phytic acid). A flexibly mounted microdialysis technique was used to detect the generation of ·OH in in vivo rat hearts. To measure the level of ·OH, sodium salicylate in Ringer's solution (0.5mM or 0.5 nmol/μl/min) was infused directly through a microdialysis probe to detect the generation of ·OH as reflected by the nonenzymatic formation of 2,3-dihydroxybenzoic acid (2,3-DHBA). To confirm the generation of ·OH by Fenton-type reaction, iron(II) was infused through a microdialysis probe. A positive linear correlation between iron(II) and the formation of 2,3-DHBA (R(2)=0.983) was observed. However, the level of 2,3-DHBA in norepinephrine (100 μM) plus phytic acid (100 μM) treated group were significantly lower than those observed in norepinephrine-only-treated group (n=6, *pphytic acid on ischemia-reperfusion-induced ·OH generation, the heart was subjected to myocardial ischemia for 15 min by occlusion of the left anterior descending coronary artery (LAD). When the heart was reperfused, the normal elevation of 2,3-DHBA in the heart dialysate was not observed in animals pretreated with phytic acid. These results suggest that phytic acid is associated with antioxidant effect due to the suppression of iron-induced ·OH generation.

  12. Free radical reaction pathway, thermohemistry of peracetic acid homolysis and its application for phenol degradation: spectroscopic sti=udy and quantum chemistry calculations

    NARCIS (Netherlands)

    Rokhina, E.V.; Makarova, K.; Golovina, E.A.; As, van H.; Virkutyte, J.

    2010-01-01

    The homolysis of peracetic acid (PAA) as a relevant source of free radicals (e.g., •OH) was studied in detail. Radicals formed as a result of chain radical reactions were detected with electron spin resonance and nuclear magnetic resonance spin trapping techniques and subsequently identified by mean

  13. Mechanism of the OH radical scavenging activity of nordihydroguaiaretic acid: a combined theoretical and experimental study.

    Science.gov (United States)

    Galano, Annia; Macías-Ruvalcaba, Norma A; Medina Campos, Omar Noel; Pedraza-Chaverri, José

    2010-05-20

    The antioxidant nordihydroguaiaretic acid (NDGA) is a plant phenolic lignan originally isolated from the creosote bush (Larrea tridentata). It has been shown that NDGA scavenges efficiently hydroxyl radicals ((*)OH). In the present paper the mechanism by which NDGA scavenges (*)OH is addressed performing a combined experimental and theoretical investigation. We found that NDGA protects, in a concentration-dependent way, bovine serum albumin and DNA from the damage induced by (*)OH generated by the Fenton reaction. In addition, the NDGA + (*)OH reaction is predicted to be diffusion-controlled. The first step of this reaction is proposed to occur mainly by a sequential electron proton transfer from NDGA to (*)OH generating a neutral radical of NDGA, which after a second oxidation step gives a diradical that after a cascade sequential complex reaction produces a cyclic compound. This cyclic product is predicted to have a UV-vis spectrum very similar to that of NDGA, making its identification by this technique very difficult. The electrochemical studies performed in water support the formation of a cyclic compound (C2) as the main product of the reaction. It is concluded that NDGA can scavenge at least two (*)OH.

  14. DDQ-promoted dehydrogenation from natural rigid polycyclic acids or flexible alkyl acids to generate lactones by a radical ion mechanism.

    Science.gov (United States)

    Ding, Ye; Huang, Zhangjian; Yin, Jian; Lai, Yisheng; Zhang, Shibo; Zhang, Zhiguo; Fang, Lei; Peng, Sixun; Zhang, Yihua

    2011-09-07

    A novel and facile DDQ-mediated dehydrogenation from natural rigid polycyclic acids or flexible alkyl acids to generate lactones is described. The formation of lactones proceeds by a radical ion mechanism, which has been established by DPPH˙-mediated chemical identification, ESR spectroscopy and an enol intermediate trapping.

  15. Determination of hydroxyl radicals with salicylic acid in aqueous nitrate and nitrite solutions

    Institute of Scientific and Technical Information of China (English)

    YANG Xi; ZHAN Man-jun; KONG Ling-ren; WANG Lian-sheng

    2004-01-01

    The qualitative and quantitative analyses of reactive oxygen species are essential to determine their steady-state concentration and related reaction mechanisms in environmental aquatic systems. In this study, salicylic acid was employed as an innovative molecular probe of hydroxyl radical(OH) generated in aqueous nitrate and nitrite solutions through photochemical reactions. Kinetic studies showed that the steady-state concentrations of OH in aqueous NO3-(10 mmol/L, pH = 5) and NO2- (10 mmol/L, pH = 5) solutions under ultraviolet irradiation were at a same magnitude, 10-15 mol/L. Apparent quantum yields of OH at 313 nm were measured as 0.011 and 0.07 for NO3- and NO2- respectively, all comparable to the results of previous studies.

  16. Lewis acid-water/alcohol complexes as hydrogen atom donors in radical reactions.

    Science.gov (United States)

    Povie, Guillaume; Renaud, Philippe

    2013-01-01

    Water or low molecular weight alcohols are, due to their availability, low price and low toxicity ideal reagents for organic synthesis. Recently, it was reported that, despite the very strong BDE of the O-H bond, they can be used as hydrogen atom donors in place of expensive and/or toxic group 14 metal hydrides when boron and titanium(III) Lewis acids are present. This finding represents a considerable innovation and uncovers a new perspective on the paradigm of hydrogen atom transfers to radicals. We discuss here the influence of complex formation and other association processes on the efficacy of the hydrogen transfer step. A delicate balance between activation by complex formation and deactivation by further hydrogen bonding is operative.

  17. A pulse radiolysis study of the dynamics of ascorbic acid free radicals within a liposomal environment.

    Science.gov (United States)

    Kobayashi, Kazuo; Seike, Yumiko; Saeki, Akinori; Kozawa, Takahiro; Takeuchi, Fusako; Tsubaki, Motonari

    2014-10-06

    The dynamics of free-radical species in a model cellular system are examined by measuring the formation and decay of ascorbate radicals within a liposome with pulse radiolysis techniques. Upon pulse radiolysis of an N2O-saturated aqueous solution containing ascorbate-loaded liposome vesicles, ascorbate radicals are formed by the reaction of OH(·) radicals with ascorbate in unilamellar vesicles exclusively, irrespective of the presence of vesicle lipids. The radicals are found to decay rapidly compared with the decay kinetics in an aqueous solution. The distinct radical reaction kinetics in the vesicles and in bulk solution are characterized, and the kinetic data are analyzed.

  18. 5-Aminosalicylic acid protection against oxidative damage to synaptosomal membranes by alkoxyl radicals in vitro.

    Science.gov (United States)

    Kanski, J; Lauderback, C; Butterfield, D A

    2001-01-01

    The antioxidant properties of 5-aminosalicylic acid in vitro were evaluated in a synaptosomal membrane system prepared from gerbil cortical synaptosomes using EPR spin labeling and spectroscopic techniques. MAL-6 (2,2,6,6-tetramethyl-4-maleimidopiperidin-1-oxyl) and 5-NS (5-nitroxide stearate) spin labels were used to assess changes in protein oxidation and membrane lipid fluidity, respectively. Synaptosomal membranes were subjected to oxidative stress by incubation with 1 mM azo-bis(isobutyronitrile) (AIBN) or 1 mM 2,2'-azobis(amidino propane) dihydrochloride (AAPH) at 37 degrees C for 30 minutes. The EPR analyses of the samples showed significant oxidation of synaptosomal proteins and a decrease in membrane fluidity. 5-Aminosalicylic acid also was evaluated by means of FRAP (the ferric reducing ability of plasma) test as a potential antioxidant. 5-Aminosalicylic acid also showed protection against the oxidation in gerbil cortical synaptosomes system caused by AIBN and AAPH. These results are consistent with the notion of antioxidant protection against free radical induced oxidative stress in synaptosomal membrane system by this agent.

  19. Examination by EPR spectroscopy of free radicals in melanins isolated from A-375 cells exposed on valproic acid and cisplatin.

    Science.gov (United States)

    Chodurek, Ewa; Zdybel, Magdalena; Pilawa, Barbara; Dzierzewicz, Zofia

    2012-01-01

    Drug binding by melanin biopolymers influence the effectiveness of the chemotherapy, radiotherapy and photodynamic therapy. Free radicals of melanins take part in formation of their complex with drugs. The aim of this work was to determine the effect of the two compounds: valproic acid (VPA) and cisplatin (CPT) on free radicals properties of melanin isolated from A-375 melanoma cells. Free radicals were examined by an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. EPR spectra were measured for the model synthetic eumelanin - DOPA-melanin, the melanin isolated from the control A-375 cells and these cells treated by VPA, CPT and both VPA and CPT. For all the examined samples broad EPR lines (deltaBpp: 0.48-0.68 mT) with g-factors of 2.0045-2.0060 characteristic for o-semiquinone free radicals were observed. Free radicals concentrations (N) in the tested samples, g-factors, amplitudes (A), integral intensities (I) and linewidths (deltaBpp) of the EPR spectra, were analyzed. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR spectra indicated that slow spin-lattice relaxation processes existed in all the tested melanin samples. The relatively slowest spin-lattice relaxation processes characterized melanin isolated from A-375 cells treated with both VPA and CPT. The changes of the EPR spectra with increasing microwave power in the range of 2.2-70 mW were evaluated. Free radicals concentrations in the melanin from A-375 cells were higher than in the synthetic DOPA-melanin. The strong increase of free radicals concentration in the melanin from A-375 cells was observed after their treating by VPA. CPT also caused the increase of free radicals concentrations in the examined natural melanin. The free radicals concentration in melanin isolated from A-375 cells treated with both VPA and CPT was slightly higher than those in melanin from the control cells.

  20. Oxygen radicals shaping evolution: why fatty acid catabolism leads to peroxisomes while neurons do without it: FADH₂/NADH flux ratios determining mitochondrial radical formation were crucial for the eukaryotic invention of peroxisomes and catabolic tissue differentiation.

    Science.gov (United States)

    Speijer, Dave

    2011-02-01

    Oxygen radical formation in mitochondria is a highly important, but incompletely understood, attribute of eukaryotic cells. I propose a kinetic model in which the ratio between electrons entering the respiratory chain via FADH₂ or NADH is a major determinant in radical formation. During the breakdown of glucose, this ratio is low; during fatty acid breakdown, this ratio is much higher. The longer the fatty acid, the higher the ratio and the higher the level of radical formation. This means that very long chain fatty acids should be broken down without generation of FADH₂ for mitochondria. This is accomplished in peroxisomes, thus explaining their role and evolution. The model explains many recent observations regarding radical formation by the respiratory chain. It also sheds light on the reasons for the lack of neuronal fatty acid (beta-) oxidation and for beneficial aspects of unsaturated fatty acids. Last but not least, it has very important implications for all models describing eukaryotic origins.

  1. Caffeic Acid Inhibits the Formation of 7-Carboxyheptyl Radicals from Oleic Acid under Flavin Mononucleotide Photosensitization by Scavenging Singlet Oxygen and Quenching the Excited State of Flavin Mononucleotide

    Directory of Open Access Journals (Sweden)

    Marie Asano

    2014-08-01

    Full Text Available We examined the effects of caffeic acid (CA and related compounds on 7-carboxyheptyl radical formation. This analysis was performed using a standard D2O reaction mixture containing 4.3 mM oleic acid, 25 μM flavin mononucleotide (FMN, 160 mM phosphate buffer (pH 7.4, 10 mM cholic acid, 100 mM α-(4-pyridyl-1-oxide-N-tert-butylnitrone, and 1 mM Fe(SO42(NH42 during irradiation with 7.8 J/cm2 at 436 nm. 7-Carboxyheptyl radical formation was inhibited by CA, catechol, gallic acid, chlorogenic acid, ferulic acid, noradrenalin, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 4-hydroxybenzoic acid. Quinic acid, benzoic acid, and p-anisic acid had no effect on radical formation. These results suggest that a phenol moiety is essential for these inhibitory effects. The fluorescence intensity of FMN decreased by 69% ± 2% after CA addition, suggesting that CA quenches the singlet excited state of FMN. When 1 mM CA was added to a standard reaction mixture containing 25 μM FMN, 140 mM phosphate buffer (pH 7.4, and 10 mM 4-oxo-2,2,6,6-tetramethylpiperidine, the electron spin resonance signal of 4-oxo-2,2,6,6-tetramethylpiperidinooxy disappeared. This finding suggests that singlet oxygen was scavenged completely by CA. Therefore, CA appears to inhibit 7-carboxyheptyl radical formation by scavenging singlet oxygen and quenching the excited state of FMN.

  2. Ascorbic Acid-Initiated Tandem Radical Cyclization of N-Arylacrylamides to Give 3,3-Disubstituted Oxindoles

    Directory of Open Access Journals (Sweden)

    Sheng Liu

    2015-08-01

    Full Text Available An ascorbic acid-promoted and metal-free tandem room temperature cyclization of N-arylacrylamides with 4-nitrobenzenediazonium generated in situ was developed. This reaction proceeds smoothly through a radical mechanism and provides an environmentally friendly alternative approach to biologically active 3-alkyl-3-benzyloxindoles, avoiding the use of excess oxidants and light irradiation.

  3. Optimization and validation of post-column assay for screening of radical scavengers in herbal raw materials and herbal preparations.

    Science.gov (United States)

    Raudonis, Raimondas; Bumblauskiene, Lina; Jakstas, Valdas; Pukalskas, Audrius; Janulis, Valdimaras

    2010-12-03

    On-line method, which combines HPLC distribution and post-column reaction, was designed for the search of individual antioxidants. Optimization of the assay was performed evaluating optimal ABTS(+) radical cation concentration in the reactor, reaction time, impact of flow rate, reaction coil length. HPLC-ABTS assay validation in this work was performed by assessing reference antioxidant negative peak areas in radical scavenging chromatogram. Sample free radical scavenging activity is expressed as trolox equivalent antioxidant capacity (TEAC). Optimized and validated method was applied in detection of compounds possessing free radical scavenging ability in complex mixtures. Antioxidant compounds were studied in perilla (Perilla frutescens (L.) Britton var. crispa f. viridis) herbal raw material and its preparations. The HPLC-separated antioxidant compounds were identified using HPLC-photodiode array coupled to mass spectrometer, using a reference mass for determining accurate masses. Radical scavenging characteristics of rosmarinic acid, which is the dominant phenolic compound in medicinal herbal raw material of perilla and its preparations, were confirmed by the calculated TEAC values. Compounds responsible for antioxidant effect in herbal raw materials and herbal preparations were identified, evaluated and compared.

  4. Edaravone, a free radical scavenger, protects liver against valproic acid induced toxicity

    Directory of Open Access Journals (Sweden)

    Cakmak Neziha Hacihasanoglu

    2015-01-01

    Full Text Available Valproic acid (VPA, is a well established anticonvulsant drug that has been increasingly used in the treatment of many forms of generalized epilepsy. Edaravone (EDA; 3-methyl-1-phenyl-2-pyrazoline-5-one is a potent free radical scavenger. In this study, we aimed to investigate the effects of EDA on VPA-induced hepatic damage. Male Sprague Dawley rats were divided into four groups. Group I was control animals. Group II was control rats given valproic acid (500 mg kg-1 day for seven days. Group III was given only EDA (30 mg kg-1day for seven days. Group IV was given VPA+EDA (in same dose and time. EDA and VPA were given intraperitoneally. On the 8th day of experiment, blood samples and liver tissue were taken. Serum aspartate and alanine aminotransferase, alkaline phosphatase and bilirubin levels, liver myeloperoxidase, xanthine oxidase, adenosine deaminase, Na+/K+ATPase, sorbitol dehydrogenase, glutamate dehydrogenase, DT-diaphorase, arginase and thromboplastic activities, lipid peroxidation, protein carbonyl levels were increased whereas paraoxonase, biotinidase activities and glutathione levels were decreased in VPA group. Application of EDA with VPA protected against VPA-induced effects. These results demonstrated that administration of EDA is a potentially beneficial agent to reduce hepatic damage in VPA induced hepatotoxicity, probably by decreasing oxidative stress.

  5. Release of reactive oxygen intermediates (superoxide radicals, hydrogen peroxide, and hydroxyl radicals) and peroxidase in germinating radish seeds controlled by light, gibberellin, and abscisic acid.

    Science.gov (United States)

    Schopfer, P; Plachy, C; Frahry, G

    2001-04-01

    Germination of radish (Raphanus sativus cv Eterna) seeds can be inhibited by far-red light (high-irradiance reaction of phytochrome) or abscisic acid (ABA). Gibberellic acid (GA3) restores full germination under far-red light. This experimental system was used to investigate the release of reactive oxygen intermediates (ROI) by seed coats and embryos during germination, utilizing the apoplastic oxidation of 2',7'-dichlorofluorescin to fluorescent 2',7'-dichlorofluorescein as an in vivo assay. Germination in darkness is accompanied by a steep rise in ROI release originating from the seed coat (living aleurone layer) as well as the embryo. At the same time as the inhibition of germination, far-red light and ABA inhibit ROI release in both seed parts and GA3 reverses this inhibition when initiating germination under far-red light. During the later stage of germination the seed coat also releases peroxidase with a time course affected by far-red light, ABA, and GA3. The participation of superoxide radicals, hydrogen peroxide, and hydroxyl radicals in ROI metabolism was demonstrated with specific in vivo assays. ROI production by germinating seeds represents an active, developmentally controlled physiological function, presumably for protecting the emerging seedling against attack by pathogens.

  6. ABT-controllable laser hyperthermia of biological objects

    Science.gov (United States)

    Krotov, Eugene V.; Yakovlev, Ivan V.; Zhadobov, Maxim; Reyman, Alexander M.

    2002-05-01

    The results of experimentally investigated laser heating of optically absorbing inhomogeneities inside the biological objects accompanied with monitoring of internal temperature by acoustical brightness thermometry (ABT) have been presented. One of the urgent problems of modern medicine is to provide organism safety during photodynamic therapy of various neoplasms including malignant ones. In the case when neoplasm differs from normal tissue mainly in optical absorption it seems to be effective to use laser heating for this purpose. In our experiments we used the NIR emission of CW and pulse-periodic Nd:YAG lasers (1064 nm) as well as CW semiconductor laser (800 nm) for heating of tissue- simulating phantom. Optically transparent gelatine with absorbing inhomogeneity inside was used as a phantom. Internal temperature was measured non-invasively by means of multi-channel ABT after long heating of an object by laser radiation. Temperature was also measured independently by contact electronic thermometer. The results of experiments demonstrated high efficiency of ABT application for internal temperature monitoring during PDT and other hyperthermia procedures. Besides that laser radiation can be used for backlighting followed by ABT investigation of internal structure of temperature distribution inside biological tissues. This work was supported by Russian Foundation for Basic Research (Projects # 00-02-16600; 01-02-06417; 01-02- 17645) and 6th competition-expertise of young scientists of Russian Academy of Sciences (Project #399).

  7. Effect of intrachain sulfonic acid dopants on the solid-state charge mobility of a model radical polymer

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Holly; Wang, Yucheng; Boudouris, Bryan W., E-mail: boudouris@purdue.edu

    2015-02-27

    Radical polymers are an emerging class of non-conjugated, charge-conducting macromolecules that are capable of transporting charge through localized oxidation–reduction (redox) reactions that occur at the stable radical groups present as the pendant groups of the macromolecular chains. The chemical nature and oxidation state of these pendant radical groups are critical to the charge transporting abilities of radical polymers in the solid state. To date, however, the control of this chemistry has been limited to external oxidizing agents, and the concept of intramolecular dopants has not been explored fully. To this end, we have synthesized poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate)-co-poly(vinylsulfonic acid sodium salt) (PTMA-co-PVS). Then, electron paramagnetic resonance spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy are implemented to evaluate the exact chemical nature of the pendant groups as a function of the PVS intramolecular dopants and exposure of the materials to external oxidation reactions. We correlate these changes in pendant group chemistry to charge transport ability, and we establish that the inclusion of a moderate amount of PVS dopants can improve the solid-state hole mobility of the material. Conversely, a large amount of sulfonic acidic dopants can be detrimental to the transport of the polymer relative to the homopolymer PTMA. Therefore, refinement of pendant group chemistry and careful addition of intramolecular dopants can enhance the solid-state transport ability of a radical polymer system. These fundamental principles, in turn, provide a vital foothold by which to optimize the solid-state charge transporting ability of current and next-generation radical polymer designs. - Highlights: • Sulfonic acid groups are copolymerized within the backbone of radical polymer chain. • Addition of the sulfonic acid groups alters the pendant group oxidation state. • Exact oxidation states are

  8. Effects of gamma-ray-induced free radicals on the metal content and amino acid composition of human metallothionein-1

    Indian Academy of Sciences (India)

    Lieven Goossens

    2011-06-01

    Metallothioneins (MTs), a low-mass class of metalloproteins, are characterized by a high thiolate sulphur and metal content. MTs are involved in metal homeostasis and heavy metal detoxification, and are efficient scavengers of free radicals. This article describes zinc release from human MT-1 and modification of its amino acid composition when subjected to free radicals generated during gamma ray radiolysis. The effect of gamma ray radiolysis of untreated and metal-depleted human MT-1 was tested under multiple aerobic and anaerobic conditions at increasing irradiation doses. Under all conditions, a rapid increase of serine in the early stages of irradiation was observed. Irradiation for longer times led to cysteic acid formation, except under argon atmosphere. Several other amino acid concentrations gradually decreased. Formation of limited amounts of hydroxyproline, hydroxylysine and ornithine as well as some less common derivatives such as cystathionine occurred as side-effects.

  9. Phytochemical analysis and free radical scavenging activity of medicinal plants Gnidia glauca and Dioscorea bulbifera.

    Science.gov (United States)

    Ghosh, Sougata; Derle, Abhishek; Ahire, Mehul; More, Piyush; Jagtap, Soham; Phadatare, Suvarna D; Patil, Ajay B; Jabgunde, Amit M; Sharma, Geeta K; Shinde, Vaishali S; Pardesi, Karishma; Dhavale, Dilip D; Chopade, Balu A

    2013-01-01

    Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS(•+) and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS(•+) radical with a second order rate constant of 2.33 × 10(6) and 1.72 × 10(6), respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48 × 10(6) and 4.46 × 10(6) were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C₂₇H₄₂O₃) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important

  10. [Lavoisier and radicals].

    Science.gov (United States)

    Lafont, Olivier

    2007-01-01

    Lavoisier and his co-workers (Guyton de Morveau, Bertholet, Fourcroy) considered that acids were constituted of oxygen and of something else that they called radicals. These radicals were known in some cases, i.e. nitrogen for nitrous acid, carbon for carbonic acid, phosphorus for phosphoric acid. In the case of sulfur, the sulfuric radical could be associated with different quantities of oxigen leading to sulfuric or sulfurous acids. In other cases radicals remained unknown at the time i.e. muriatic radical for muriatic acid, or benzoyl radical for benzoic acid. It is interesting to notice that Lavoisier evoked the case of compound radicals constituted of different substances such as carbon and hydrogen.

  11. Screening of radical scavenging activity of some medicinal and aromatic plant extracts

    NARCIS (Netherlands)

    Miliauskas, G.; Venskutonis, R.P.; Beek, van T.A.

    2004-01-01

    Extracts of 12 medicinal and aromatic plants were investigated for their radical scavenging activity using DPPH and ABTS assays: Salvia sclarea, Salvia glutinosa, Salvia pratensis, Lavandula angustifolia, Calendula officinalis, Matricaria recutita, Echinacea purpurea, Rhaponticum carthamoides, Jugla

  12. Caffeic acid inhibits the formation of 1-hydroxyethyl radical in the reaction mixture of rat liver microsomes with ethanol partly through its metal chelating activity.

    Science.gov (United States)

    Ikeda, Hideyuki; Kimura, Yuka; Masaki, Miho; Iwahashi, Hideo

    2011-05-01

    Effect of caffeic acid on the formation of 1-hydroxyethyl radicals via the microsomal ethanol-oxidizing system pathway was examined. The electron spin resonance spin trapping showed that 1-hydroxyethyl radicals form in the control reaction mixture which contained 0.17 M ethanol, 1 mg protein/ml rat river microsomes, 0.1 M α-(4-pyridyl-1-oxide)-N-tert-butylnitrone, 5 mM nicotinamide adenine dinucleotide phosphate and 30 mM phosphate buffer (pH 7.4). When the electron spin resonance spectra of the control reaction mixtures with caffeic acid were measured, caffeic acid inhibited the formation of 1-hydroxyethyl radicals in a concentration dependent manner. Gallic acid, dopamine, l-dopa, chlorogenic acid and catechin also inhibited the formation of 1-hydroxyethyl radicals. Above results indicated that the catechol moiety is essential to the inhibitory effect. Caffeic acid seems to chelate of iron ion at the catechol moiety. Indeed, the inhibitory effect by caffeic acid was greatly diminished in the presence of desferrioxamine, a potent iron chelator which removes iron ion in the Fe (III)-caffeic acid complex. Since Fe (III)-desferrioxamine complex is active for the 1-hydroxyethyl radicals formation, caffeic acid inhibits the formation of 1-hydroxyethyl radicals in the reaction mixture partly through its metal chelating activity.

  13. Increased fatty acid synthase expression in prostate biopsy cores predicts higher Gleason score in radical prostatectomy specimen

    OpenAIRE

    HAMADA, SHINSUKE; Horiguchi, Akio; Kuroda, Kenji; Ito, Keiichi; ASANO, TOMOHIKO; Miyai, Kosuke; Iwaya, Keiichi

    2014-01-01

    Background Fatty acid synthase (FAS) is highly expressed in various types of cancer, and elevated expression of FAS has been suggested to be a predictor of tumor aggressiveness and poor prognosis. We examined whether FAS expression in prostate biopsy cores could predict the pathological characteristics of radical prostatectomy (RP) specimens. Methods Paraffin-embedded prostate biopsy cores, obtained from 102 patients who subsequently underwent RP, were immunostained with polyclonal anti-FAS a...

  14. Antioxidative activities of white rose flower extract and pharmaceutical advantages of its hexane fraction via free radical scavenging effects.

    Science.gov (United States)

    Park, Dongsun; Jeon, Jeong Hee; Kwon, Sang-Chul; Shin, Sunhee; Jang, Ja Young; Jeong, Heon Sang; Lee, Do Ik; Kim, Yun-Bae; Joo, Seong Soo

    2009-12-01

    In this study, we determined the antioxidant activities of two different solvent fractions(butanol and hexane) obtained from white Rosa rugosa flowers by employing various assays such as 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and nitric oxide (NO) scavenging and inhibition activity in S-nitroso-N-acetylpenicillamine (SNAP) in the RAW264.7 model. In addition, more advanced antioxidant assays were conducted, including lipid peroxidation, hydroxyl radical-mediated oxidation, DNA fragmentation, apoptosis, and cell growth. The results revealed that the hexane fraction, which contained a significant amount of polyphenols and volatile components, had excellent antioxidant potency and could scavenge free radicals of DPPH and ABTS. Interestingly, the hexane fraction inhibited lipid peroxidation to almost the same degree as a chemical antioxidant. In the NO assay, the hexane fraction effectively scavenged free radicals at all dose ranges and is expected to inhibit NO production in mammalian cells. The hexane fraction effectively prevented oxidative damage, which was induced by Cu2+/H2O2, to target proteins at lower concentrations (>1 microg x mL(-1)). The DNA fragmentation and the cell-level assays suggest that the hexane fraction may play a crucial role in inhibiting peroxynitrite and H2O2 attack. Based on the findings described in this study, the hexane fraction holds promise for use as a novel pharmaceutical antioxidant.

  15. Thermal Behavior and Free-Radical-Scavenging Activity of Phytic Acid Alone and Incorporated in Cosmetic Emulsions

    Directory of Open Access Journals (Sweden)

    André Luis Máximo Daneluti

    2015-07-01

    Full Text Available Phytic acid is a natural compound widely used as depigmenting agent in cosmetic emulsions. Few studies are available in the literature covering the stability and the antioxidating property of this substance, used alone or into emulsions. Therefore, the purpose of this work was to investigate the thermal behavior and antioxidant properties of phytic acid alone and into cosmetic emulsions. The thermal behavior of this substance was evaluated by thermogravimetry (TG/derivative thermogravimetry (DTG and differential scanning calorimetry (DSC and the free-radical-scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH. TG/DTG and DSC curves allowed evaluation of the thermal behavior of phytic acid. These results showed that the substance presented four stages of mass loss. Thermal decomposition of the material initiated at 150 °C. Thermal behavior of the cosmetic emulsions detected that the addition of phytic acid decreased the thermal stability of the system. DPPH free-radical-scavenging activity showed that phytic acid incorporated into emulsion had no antioxidant capacity compared to BHT. In summary, we concluded that the thermoanalytical techniques (TG and DSC were efficient and reliable in the characterization of phytic acid alone and incorporated into cosmetic emulsions.

  16. Radical scavenging and antimicrobial activity of essential oil and extracts of Echinophora sibthorpiana Guss. from Macedonia

    Directory of Open Access Journals (Sweden)

    Mileski Ksenija

    2014-01-01

    Full Text Available This study was undertaken to determine the antioxidant and antimicrobial effect of essential oil and extracts of Echinophora sibthorpiana Guss. (fam. Apiaceae collected in Macedonia. The chemical composition of E. sibthorpiana essential oil was characterized by the presence of methyl eugenol (60.40%, p-cymene (11.18% and α-phellandrene (10.23%. The free radical scavenging activity of extracts and essential oil was evaluated by DPPH and ABTS assays. The aqueous extract of aerial parts exhibited the strongest scavenging activity (IC50=1.67 mg/ml; results of the ABTS test showed that the most effective was the ethanol extract of aerial parts (1.11 mg vit. C/g. The essential oil showed stronger antioxidant activity compared to hydroxyanisole, ascorbic acid and quercetin that were used in the DPPH and ABTS tests, respectively. The total phenolic and flavonoid concentrations in the extracts ranged between 38.65-60.72 mg GA/g, and 3.15-19.00 mg Qu/g, respectively. The antimicrobial properties of the extracts and essential oil were investigated using a micro-well dilution technique against human pathogenic strains. The results were comparable with the effects of the positive controls, streptomycin and fluconazole. These findings indicate that E. sibthorpiana extracts and oil can be used in preventive treatments and as an alternative for synthetic preservatives. [Projekat Ministarstva nauke Republike Srbije, br. 173029 i br. 173021

  17. Pulse radiolysis studies of short-lived species in solid amino acids as precursors of radicals and detected by ESR

    Science.gov (United States)

    Zagórski, Z. P.; Gładysz, Katarzyna

    1995-06-01

    The aim of the study was to bring closer solid state radiation chemistry and ESR spectroscopy by looking for precursors of free radicals which give ESR signals. It has been performed using time-resolved spectrophotometry (pulse radiolysis of the solid state) and diffuse reflection spectrophotometry. Alanine has been especially considered as the most investigated amino acid, important for radiation dosimetry. Absorption of the transient (Λ maximum at 460 nm) is identified as the species during deamination. The stable absorption spectrum with the Λ maximum at 345 nm is due to the same radical as the one detected by ESR. Other amino acids: valine, threonine, glutamine and arginine show similar behaviour: microsecond spectrum of the intermediate appears always at longer wavelenghts. The transient spectrum changes into stable absorption in UV of a lower wavelenght. Along with the optical spectrum, the ESR spectrum appears, of similar stability. Also, other features indicate that the same radical is responsible for both the electronic and ESR spectrum. Some amino acids, like methionine give intensive transient absorption in the microsecond range but no ESR signal, after completion of consecutive fast reactions. In that case any optical absorption is due to the stable product of radiolysis, i.e. compounds with paired electrons only.

  18. Structure and Reactivity of the Glutathione Radical Cation: Radical Rearrangement from the Cysteine Sulfur to the Glutamic Acid alpha-Carbon Atom

    NARCIS (Netherlands)

    Osburn, S.; Berden, G.; Oomens, J.; Gulyuz, K.; Polfer, N.C.; O'Hair, R.A.J.; Ryzhov, V.

    2013-01-01

    A gas-phase radical rearrangement through intramolecular hydrogen-atom transfer (HAT) was studied in the glutathione radical cation, [-ECG](+.), which was generated by a homolytic cleavage of the protonated S-nitrosoglutathione. Ion-molecule reactions suggested that the radical migrates from the ori

  19. The Rate of Decolorization of a Radical Ion Reagent Was Used to Determine the Phenolic Content of Various Food Extracts

    Directory of Open Access Journals (Sweden)

    Arthur Bradley

    2013-01-01

    Full Text Available Polyphenols are among the most valuable and widely studied food components. In the laboratory, they are readily extractable with aqueous alcohol. An aliquot rapidly decolorizes a measured portion of ABTS, a stable deep blue radical ion. The semilog plot of light absorption versus time is typically a straight line, and an immediately evident slope provides rapid classification in terms of gallic acid equivalents. Experimental data are presented to show general agreement with the literature. The disproportionate concentration of antioxidant in the skins and peels of fruits, vegetables, and nuts is given special attention.

  20. Increased electrical output when a bacterial ABTS oxidizer is used in a microbial fuel cell.

    Science.gov (United States)

    Hunter, William J; Manter, Daniel K

    2011-02-01

    Microbial fuel cells (MFCs) are a technology that provides electrical energy from the microbial oxidation of organic compounds. Most MFCs use oxygen as the oxidant in the cathode chamber. This study examined the formation in culture of an unidentified bacterial oxidant and investigated the performance of this oxidant in a two-chambered MFC with a proton exchange membrane and an uncoated carbon cathode. DNA, FAME profile and characterization studies identified the microorganism that produced the oxidant as Burkholderia cenocepacia. The oxidant was produced by log phase cells, oxidized the dye 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), had a mass below 1 kD, was heat stable (121°C) and was soluble in ethanol. In a MFC with a 1000 Ω load and ABTS as a mediator, the oxidizer increased cell voltage 11 times higher than atmospheric oxygen and 2.9 times higher than that observed with ferricyanide in the cathode chamber. No increase in cell voltage was observed when no mediator was present. Organisms that produce and release oxidizers into the media may prove useful as bio-cathodes by improving the electrical output of MFCs.

  1. Mechanisms for the formation of isoprostane endoperoxides from arachidonic acid. "Dioxetane" intermediate versus beta-fragmentation of peroxyl radicals.

    Science.gov (United States)

    Yin, Huiyong; Havrilla, Christine M; Gao, Ling; Morrow, Jason D; Porter, Ned A

    2003-05-09

    The isoprostanes are a class of autoxidation products generated from arachidonic acid (or its esters) by a free radical initiated process. The potent biological activity of these compounds has been attracting intense research interest since they were detected in humans as well as animal models in the early 1990s. The measurement of these compounds has been regarded as one of the most useful non-invasive biomarkers for oxidative stress status. Two mechanisms for the formation of these compounds have been proposed. In the first mechanism, a peroxyl radical undergoes successive 5-exo cyclizations analogous to the enzymatic mechanism proposed for prostaglandin biosynthesis. The second mechanism starts with a 4-exo cyclization of a peroxyl radical leading to an intermediate dioxetane, a mechanism that has also been proposed for prostaglandin biosynthesis as well as for the formation of 4-hydroxy nonenal (HNE). Autoxidation of cholesteryl-15-HpETE under free radical conditions provides Type IV isoprostanes. The "dioxetane" mechanism for isoprostane generation from 15-HpETE requires that optically pure products are formed from an optically pure reactant, whereas an alternate mechanism for the process involving beta-fragmentation of the 15-peroxyl would give racemic isoprostane products. We have carried out a test of the mechanism based upon these stereochemical requirements. The results of analysis of the product mixture derived from autoxidation of optically pure Ch-15-HpETE by atmospheric pressure chemical ionization-mass spectrometry coupled with chiral high performance liquid chromatography indicate that the major isoprostane diastereomers are formed as a racemic mixture. These experimental results are consistent with a mechanism for isoprostane formation involving beta-fragmentation of the 15-peroxyl radical followed by re-addition of oxygen to form the 11-HPETE peroxyl, and they exclude a mechanism proceeding through the formation of a dioxetane intermediate.

  2. In vitro Free Radical Scavenging Potential of Indian Habitant Anisochilus carnosus (L.F.) Wall

    Institute of Scientific and Technical Information of China (English)

    Jaykumar Bhagat; Richard Lobo; Vinit Parmar; Mamatha Ballal

    2011-01-01

    AIM:To evaluate in vitro anti-oxidant potential of methanolic and aqueous extract of Indian habitants Anisochilus carnosus (L.F.) wall.,which is an annual shrub belonging to the family Lamiaceae commonly known as mint family.METHODS:The present study describes the effects by DPPH,alkaline DMSO,scavenging of ferric ion,NO,H2O2.ABTS models.Both extracts showed good free radical scavenging property which was calculated as IC50.RESULTS:IC50 of aqueous and methanolic extracts were found to be 7.09 and 5.77 μg.mL-1 for DPPH,8.14 and 13.29 μg·mL-1 for alkaline DMSO,27.16 and 31.25 μg·mL-1 for scavenging of ferric ion,13.82 and 26.94 μg.mL-1 for NO,13.82 and 26.94 μg.mL-1 for H2O2,113.84 and 128.03 μg.mL-1 for ABTS,whic1h were compared with Ascorbic acid (DPPH,scavenging of ferric ion,NO,ABTS) and rutin (alkaline DMSO,H2O2).Total antioxidant capacity of the extract was found to be 213 and 172 μg.mL-1 ascorbic acid for methanolic and aqueous extracts respectively.CONCLUSION:A.carnosus leaf extracts exhibited potent free radical scavenging activity.The overall antioxidant activity is attributed to its polyphenolic and other phytochemical constituents.The findings suggest that A.carnosus leaves could be a potential source of natural antioxidant in preventing or slowing the progression of aging and age-associated oxidative stress-related degenerative diseases.

  3. Ferulic acid antioxidant protection against hydroxyl and peroxyl radical oxidation in synaptosomal and neuronal cell culture systems in vitro: structure-activity studies.

    Science.gov (United States)

    Kanski, Jaroslaw; Aksenova, Marina; Stoyanova, Antonia; Butterfield, D Allan

    2002-05-01

    In this study, free radical scavenging abilities of ferulic acid in relation to its structural characteristics were evaluated in solution, cultured neurons, and synaptosomal systems exposed to hydroxyl and peroxyl radicals. Cultured neuronal cells exposed to the peroxyl radical initiator AAPH die in a dose-response manner and show elevated levels of protein carbonyls. The presence of ferulic acid or similar phenolic compounds, however, greatly reduces free radical damage in neuronal cell systems without causing cell death by themselves. In addition, synaptosomal membrane systems exposed to oxidative stress by hydroxyl and peroxyl radical generators show elevated levels of oxidation as indexed by protein oxidation, lipid peroxidation, and ROS measurement. Ferulic acid greatly attenuates these changes, and its effects are far more potent than those obtained for vanillic, coumaric, and cinnamic acid treatments. Moreover, ferulic acid protects against free radical mediated changes in conformation of synaptosomal membrane proteins as monitored by EPR spin labeling techniques. The results presented in this study suggest the importance of naturally occurring antioxidants such as ferulic acid in therapeutic intervention methodology against neurodegenerative disorders such as Alzheimer's disease in which oxidative stress is implicated.

  4. Uric acid substantially enhances the free radical-induced inactivation of alcohol dehydrogenase.

    Science.gov (United States)

    Kittridge, K J; Willson, R L

    1984-05-01

    Lactate dehydrogenase (LDH) and yeast alcohol dehydrogenase ( YADH ) are inactivated when attacked by hydroxy free radicals (OH). Organic molecules with a high rate constant of reaction with OH such as ascorbate or urate can compete with the enzymes for these strongly oxidising radicals. However, although 10(-3)M ascorbate can substantially protect both LDH and YADH from OH attack, in the presence of 10(-3)M urate only LDH is protected. In the case of YADH an even greater degree of inactivation than with OH occurs. The extent of inactivation is considerably reduced when oxygen is absent, in agreement with a urate peroxy radical perhaps being partly responsible for the increased inactivation of the enzyme.

  5. EPR studies of free radicals in A-2058 human melanoma cells treated by valproic acid and 5,7-dimethoxycoumarin.

    Science.gov (United States)

    Zdybel, Magdalena; Chodurek, Ewa; Pilawa, Barbara

    2014-01-01

    Free radicals in A-2058 human melanoma cells were studied by the use of electron paramagnetic resonance (EPR) spectroscopy. The aim of this work was to determine the changes in relative free radical concentrations in tumor A-2058 cells after treatment by valproic acid (VPA) and 5,7-dimethoxycoumarin (DMC). The influences of VPA and DMC on free radicals in A-2058 cells were compared with those for human melanoma malignum A-375 and G-361 cells, which were tested by us earlier. Human malignant melanoma A-2058 cells were exposed to interactions with VPA, DMC, and both VPA and DMC. The tumor cells A-2058 were purchased from LGC Standards (Lomianki, Poland), and they were grown in the standard conditions: at 37°C and in an atmosphere containing 95% air and 5% CO2, in the Minimum Essential Medium Eagle (MEM, Sigma-Aldrich). The A-2058 cells were incubated with VPA (1 mM) and DMC (10 μM) for 4 days. The first-derivative EPR spectra of the control A-2058 cells, and the cells treated with VPA, DMC, and both VPA and DMC, were measured by the electron paramagnetic resonance spectrometer of Radiopan (Poznań, Poland) with microwaves from an X-band (9.3 GHz). The parameters of the EPR lines: amplitudes (A), integral intensities (I), line widths (ΔBpp), and g-factors, were analyzed. The changes of amplitudes and line widths with microwave power increasing from 2.2 to 70 mW were drawn evaluated, o-Semiquinone free radicals of melanin biopolymer are mainly responsible for the EPR lines of A-2058 melanoma malignum cells. The amounts of free radicals in A-2058 cells treated with VPA, and both VPA and DMC, were lower than in the untreated control cells. Application of the tested substances (VPA, and both VPA and DMC) as the antitumor compounds was discussed. DMC without VPA did not decrease free radicals concentration in A-2058 cells. The studies con-firmed that EPR spectroscopy may be used to examine interactions of free radicals with antitumor compounds.

  6. Effect of indole-3-acetic acid on pea root growth, peroxidase profiles and hydroxyl radical formation

    Directory of Open Access Journals (Sweden)

    Kukavica Biljana

    2007-01-01

    Full Text Available Changes in growth, peroxidase profiles, and hydroxyl radical formation were examined in IAA (0.5-10 mg/l treated pea plants grown hydroponically and in isolated roots in liquid in vitro culture. IAA inhibited root elongation, both in hydroponically grown pea plants and in isolated roots in vitro. A remarkable increase in the number of POD iso­forms was noticed in isolated roots grown in vitro, compared to the roots from plants grown hydroponically. IAA induced both disappearance of several root POD isoforms and hydroxyl radical formation in the root and the root cell wall.

  7. Clinical efficacy ofω-3 polyunsaturated fatty acids in perioperative period of radical operation for gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Wei-Xue Li; Shan-Min Wu; Tao Zeng

    2016-01-01

    Objective:To study the regulating effect of application ofω-3 polyunsaturated fatty acids in perioperative period of radical surgery for gastric cancer on patients’ nutritional status, inflammatory response and immune function.Methods:A total of86 cases of patients receiving radical operation for gastric cancer in our hospital were selected for study and randomly divided into two groups,ω-3 PUFAs group receivedω-3 polyunsaturated fatty acids combined with conventional intravenous nutritional support and control group only received conventional intravenous nutritional support. Serum nutrition indicators of two groups were detected before and after surgery, and inflammation indicators in serum as well as immune molecules in tumor tissue of tow groups were detected after surgery.Results:1d before operation and 3 d after operation, serum RBP, PA, RTF, PEPT1 and ghrelin contents ofω-3 PUFAs group were significantly higher than those of control group; 3 d after operation, serum CC16, α-MSH and HSP70 contents ofω-3 PUFAs group were significantly higher than those of control group, and LBP and sCD14 contents were significantly lower than those of control group; B7-H1, B7-H4, CD157 and CD133 contents in tumor tissue of ω-3 PUFAs group were significantly lower than those of control group, and CD11c content was significantly higher than that of control group.Conclusion:Application ofω-3 polyunsaturated fatty acids in perioperative period of radical operation for gastric cancer can improve patients’ nutritional status, reduce postoperative inflammatory response caused by surgical trauma and regulate the expression of immune molecules in tumor tissue.

  8. Reactivity of OH radicals with chlorobenzoic acids-A pulse radiolysis and steady-state radiolysis study

    DEFF Research Database (Denmark)

    Zona, Robert; Solar, Sonja; Getoff, Nikola

    2010-01-01

    The reactions of OH radicals with 2-, 3-, 4-chlorobenzoic acids (ClBzA) and chlorobenzene (ClBz), k(OH+substrates)=(4.5−6.2)×109 dm3 mol−1 s−1, have been studied by pulse radiolysis in N2O saturated solutions. The absorption maxima of the OH-adducts were in the range of 320−340 nm. Their decay wa...... to degradation. The order for the efficiency of dehalogenation was 4->2->3-ClBzA. Several primary radiolytic products could be detected by HPLC. To evaluate the toxicity of final products a bacterial bioluminescence test was carried out....

  9. Catalytic Mechanism and Efficiency of Methane Oxidation by Hg(II) in Sulfuric Acid and Comparison to Radical Initiated Conditions

    OpenAIRE

    Fuller, Jack T.; Butler, Steven; Devarajan, Deepa; Jacobs, Austin; Hashiguchi, Brian G.; Konnick, Michael M.; Goddard, William A.; Gonzales, Jason M.; Periana, Roy A.; Ess, Daniel H.

    2016-01-01

    Methane conversion to methyl bisulfate by Hg^(II)(SO_4) in sulfuric acid is an example of fast and selective alkane oxidation catalysis. Dichotomous mechanisms involving C–H activation and electron transfer have been proposed based on experiments. Radical oxidation pathways have also been proposed for some reaction conditions. Hg^(II) is also of significant interest because as a d^(10) transition metal it is similar to d^(10) main-group metals that also oxidize alkanes. Density-functional cal...

  10. Preparation of Polystyrenylphosphonous Acid of Low Polymerization Degree and Influence of Initiators upon the Free Radical Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, there are 2 or 3 series of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH (C6H5)]n-PO2H2 respectively.

  11. Preparation of Polystryenylphosphonous Acid of Low Polymerization Degree and Influence of Initiators upon the Free Radical Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    XiangKaiFU; YanSUI; 等

    2002-01-01

    The polystyrenylphosphonous acid (PSPA) of low polymerization degress was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, therer are 2 or 3 serives of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH(C6H5)]n-PO2H2 respectively.

  12. Interaction of gold nanoparticles with free radicals and their role in enhancing the scavenging activity of ascorbic acid.

    Science.gov (United States)

    Razzaq, Humaira; Saira, Farhat; Yaqub, Azra; Qureshi, Rumana; Mumtaz, Misbah; Saleemi, Samia

    2016-08-01

    The present study investigates the interaction of citrate stabilized gold nanoparticles (12±1.5nm) (GNPs) with free radicals; 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable and electrochemically generated superoxide, O2(-). Different experiments were designed to understand the interaction between GNPs and DPPH by employing cyclic voltammetry, UV-vis spectroscopy and computational chemistry using 6-311G basis set. The increase in heterogeneous rate constant, ksh, of DPPH upon addition of GNPs pointed towards possible complex formation, DPPH-GNPs which were further explained by a model assuming surface adsorption of DPPH on GNPs. Further, the model was validated by studying interaction of GNPs with a biologically important free radical, O2(-). Exciting result in terms of disappearance of anodic peak after GNPs addition confirmed that gold nanoparticles interacted with stable as well as unstable free radicals. Also, the stoichiometry of the most stable complex GNP-DPPH was determined from UV-vis spectroscopy by applying Job's method. The GNP-DPPH complex was found to be active with 46.0% reduction of the IC50 value of standard antioxidant, ascorbic acid (AA), indicating its role in enhancing antioxidant activity. Hence, this study presents a simple and potential approach to enhance the efficiency of natural antioxidants without modifying their structure, or involving the complex functionalization of GNPs with antioxidants.

  13. Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures

    Directory of Open Access Journals (Sweden)

    Chunpeng Wan

    2011-01-01

    Full Text Available Background: Extraction temperature influences the total phenolic content (TPC, total flavonoid content (TFC of medicinal plant extracts to a great extend. TPC and TFC are the principle activity constituents present in the plant. The effects of extraction temperature on TPC, TFC and free radical-scavenging capacity of Gynura divaricata leaf extracts are worth to study. Materials and Methods: Folin-Ciocalteu and aluminum chloride colorimetric assay were used to determine the TPC and TFC of Gynura divaricata leaf extracts at different temperatures. The antioxidant and free radical-scavenging activity were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS and phosphomolybdenum methods. Results: TPC and TFC were significantly elevated with increasing extraction temperature (from 40°C to 100°C. However, TPC and TFC were not significantly different (P > 0.05 at the extraction temperatures 90°C and 100°C. Also, the extracts obtained at a higher temperature exhibited a significant free radical-scavenging activity compared with extraction at lower temperatures (P < 0.05. The TPCs (13.95-36.68 mg gallic acid equivalent/g dry material were highly correlated with DPPH (R2 = 0.9229, ABTS (R2 = 0.9951 free radical-scavenging capacity, and total antioxidant activity (R2 = 0.9872 evaluated by phosphomolybdenum method. Conclusion: The TPC and TFC of G. divaricata leaf was significantly influenced by the extraction temperatures, which were the main antioxidant constituents present in the G. divaricata plant.

  14. Spectroscopic studies on the antioxidant activity of p-coumaric acid

    Science.gov (United States)

    Kiliç, Ismail; Yeşiloğlu, Yeşim

    2013-11-01

    p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid 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-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPHrad 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 p-coumaric acid can be used in the pharmacological and food industry because of these properties.

  15. Chemical Constituents with Free-Radical-Scavenging Activities from the Stem of Microcos paniculata

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2010-08-01

    Full Text Available The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate (ABTS and Co (II EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc extract showed the highest free-radical-scavenging activity compared with the other three (n-BuOH, water and petroleum ether extracts. Free-radical-scavenging assay-guided chromatographic separation of the EtOAc extract, using a normal-phase and reverse-phase silica gel column chromatography yielded five compounds: a new triterpene named methyl 3b-O-p-hydroxy-E-cinnamoyloxy-2a,23-dihydroxyolean-12-en-28-oate (1, whose spectral data are presented for the first time, together with four known compounds, epicatechin (2, 3-trans-feruloyl maslinic acid (3, maslinic acid (4 and sucrose (5. All of the compounds were isolated from Microcos paniculata for the first time. The compounds were identified by spectroscopic methods. Among them, compound 2 displayed significant free-radical-scavenging activity which is similar to that of standard antioxidant ascorbic acid (VC and therefore may be a promising natural antioxidant.

  16. Immobilized transition metal-based radical scavengers and their effect on durability of Aquivion® perfluorosulfonic acid membranes

    Science.gov (United States)

    D'Urso, C.; Oldani, C.; Baglio, V.; Merlo, L.; Aricò, A. S.

    2016-01-01

    A simple and broadly applicable preparation procedure to obtain silica-supported transition metal (namely Cr, Co and Mn)-based radical scavengers, containing sulfonic acid functionalities, is reported. These systems are widely characterised in terms of structure, bulk and surface composition and morphology by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The scavenger material is loaded in ePTFE reinforced membranes prepared from Aquivion® perfluorosulfonic acid (PFSA) dispersions. All these composite membranes show longer lifetime in Accelerated Stress Tests (AST) and reduced fluoride release in Fenton's tests than the scavenger-free membranes without any loss in electrochemical performance. The Cr-scavenger-based polymer electrolyte shows a three-time larger stability than the pristine membrane.

  17. Radical S-adenosyl methionine epimerases: regioselective introduction of diverse D-amino acid patterns into peptide natural products.

    Science.gov (United States)

    Morinaka, Brandon I; Vagstad, Anna L; Helf, Maximilian J; Gugger, Muriel; Kegler, Carsten; Freeman, Michael F; Bode, Helge B; Piel, Jörn

    2014-08-04

    PoyD is a radical S-adenosyl methionine epimerase that introduces multiple D-configured amino acids at alternating positions into the highly complex marine peptides polytheonamide A and B. This novel post-translational modification contributes to the ability of the polytheonamides to form unimolecular minimalistic ion channels and its cytotoxic activity at picomolar levels. Using a genome mining approach we have identified additional PoyD homologues in various bacteria. Three enzymes were expressed in E. coli with their cognate as well as engineered peptide precursors and shown to introduce diverse D-amino acid patterns into all-L peptides. The data reveal a family of architecturally and functionally distinct enzymes that exhibit high regioselectivity, substrate promiscuity, and irreversible action and thus provide attractive opportunities for peptide engineering.

  18. Dissociations of copper(II)-containing complexes of aromatic amino acids: radical cations of tryptophan, tyrosine, and phenylalanine.

    Science.gov (United States)

    Siu, Chi-Kit; Ke, Yuyong; Guo, Yuzhu; Hopkinson, Alan C; Siu, K W Michael

    2008-10-14

    The dissociations of two types of copper(II)-containing complexes of tryptophan (Trp), tyrosine (Tyr), or phenylalanine (Phe) are described. The first type is the bis-amino acid complex, [Cu(II)(M)(2)].(2+), where M = Trp, Tyr, or Phe; the second [Cu(II)(4Cl-tpy)(M)].(2+), where 4Cl-tpy is the tridendate ligand 4'-chloro-2,2':6',2''-terpyridine. Dissociations of the Cu(ii) bis-amino acid complexes produce abundant radical cation of the amino acid, M.(+), and/or its secondary products. By contrast, dissociations of the 4Cl-tpy-bearing ternary complexes give abundant M.(+) only for Trp. Density functional theory (DFT) calculations show that for Tyr and Phe, amino-acid displacement reactions by H(2)O and CH(3)OH (giving [Cu(II)(4Cl-tpy)(H(2)O)].(2+) and [Cu(II)(4Cl-tpy)(CH(3)OH)].(2+)) are energetically more favorable than dissociative electron transfer (giving M.(+) and [Cu(I)(4Cl-tpy)](+)). The fragmentation pathway common to all these [Cu(II)(4Cl-tpy)(M)].(2+) ions is the loss of NH(3). DFT calculations show that the loss of NH(3) proceeds via a "phenonium-type" intermediate. Dissociative electron transfer in [Cu(II)(4Cl-tpy)(M-NH(3))].(2+) results in [M-NH(3)].(+). The [Phe-NH(3)] (+) ion dissociates facilely by eliminating CO(2) and giving a metastable phenonium-type ion that rearranges readily into the styrene radical cation.

  19. Visible-Light Photoredox-Catalyzed Giese Reaction: Decarboxylative Addition of Amino Acid Derived α-Amino Radicals to Electron-Deficient Olefins

    KAUST Repository

    Millet, Anthony

    2016-06-20

    A tin- and halide-free, visible-light photoredox-catalyzed Giese reaction was developed. Primary and secondary α-amino radicals were generated readily from amino acids in the presence of catalytic amounts of an iridium photocatalyst. The reactivity of the α-amino radicals has been evaluated for the functionalization of a variety of activated olefins. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  20. Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NOx cycle and implication on radical chemistry

    Directory of Open Access Journals (Sweden)

    J. L. Li

    2010-01-01

    Full Text Available Peroxyacetic acid (PAA is one of the most important atmospheric organic peroxides, which have received increasing attention for their potential contribution to the oxidation capacity of the troposphere and the formation of secondary aerosols. We report here, for the first time, a series of data for atmospheric PAA concentrations at urban and rural sites, from five field campaigns carried out in China in summer 2006, 2007 and 2008. For these five measurements, daytime mean (08:00–20:00 LT PAA concentrations on sunlit days were 21.4–148.0 pptv with a maximum level of ~1 ppbv. The various meteorological and chemical parameters influencing PAA concentrations were examined using Principal Factor Analysis. This statistical analysis shows that the local photochemical production was the major source of PAA, and its concentration increased with increasing temperature, solar radiation and ozone but decreased with increasing NOx (NO and NO2, CO, SO2, and relative humidity. Based on the dataset, several issues are highlighted in this study: (i Because PAA is a product from the photochemical oxidation of some specific volatile organic compounds (VOCs that lead to acetyl peroxy radicals, the importance of various VOCs with respect to the PAA formation is therefore ranked using the incremental reactivity method. (ii The contribution of PAN thermal degradation to PAA formation under conditions of different NOx concentrations is estimated based on the chemical kinetics analysis. The result shows that PAN seems to play an important role in the formation of PAA when the NO/NO2 concentration ratio was less than 0.2 and PAA would correspondingly have feedback on the PAN-NOx cycle. (iii PAA and other peroxides, such as methyl hydroperoxide (MHP and H2O2, usually exhibited a similar asymmetric shape typically shifted to the afternoon. However, under some conditions, H2O2 diurnal cycle was out of phase with MHP and PAA. The combination of linear regression and

  1. Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NOx cycle and implication on radical chemistry

    Directory of Open Access Journals (Sweden)

    J. L. Li

    2009-10-01

    Full Text Available Peroxyacetic Acid (PAA is one of important atmospheric organic peroxides, which have received increasing attention for their potential contribution to the oxidation capacity of the troposphere and the formation of secondary aerosols. We report here that, for the first time, a series of data for atmospheric PAA concentrations at urban and rural sites, from five field campaigns carried out in China in summer 2006, 2007 and 2008. For these five measurements, daytime mean PAA concentrations on sunlit days were 0.02–0.14 ppbv with a maximum level of ~1 ppbv. The various meteorological and chemical parameters influencing PAA concentrations were examined using the Principal Factor Analysis. This statistical analysis shows that the local photochemical production was the major source of PAA, and its concentration increased with increasing temperature, solar radiation and ozone but decreased with increasing NOx (NO and NO2, CO, SO2, and relative humidity. Based on the dataset, several issues are highlighted in this study: (i because PAA is a product from the photochemical oxidation of some specific volatile organic compounds (VOCs that lead to acetyl peroxy radicals, the importance of various VOCs with respect to the PAA formation is therefore ranked using the incremental reactivity method. (ii The contribution of PAN thermal degradation to PAA formation under conditions of different NOx concentrations is estimated based on the chemical kinetics analysis. The result shows that PAN seems to play an important role in the formation of PAA when the NO/NO2 concentration ratio was less than 0.2 and PAA would correspondingly have feedback on the PAN-NOx cycle. (iii PAA and other peroxides, such as methyl hydroperoxide (MHP and H2O2, usually exhibited a similar asymmetric shape typically shifted to the afternoon. However, at a high SO2 level, H2O2 showed a profile different from those of MHP and PAA. The combination of linear regression and chemical kinetics

  2. Effect of ascorbic acid (vitamin C) on the ESR spectra of the red and black hair: pheomelanin free radicals are not always present in red hair.

    Science.gov (United States)

    Chikvaidze, Eduard; Topeshashvili, Maia

    2015-12-01

    Increased incidence of melanoma in the population with red hair is conditioned by synthesis of pheomelanin pigments in the skin and their phototoxic properties. The recent research has shown that free radicals of pheomelanin are produced not only by the influence of UV irradiation, but also in UV-independent pathways of oxidative stress. It has been ascertained, that the color of the hair is not always determinant of the amount of pheolemanin radicals in red hair. Therefore, in order to evaluate the risk of melanoma in different individuals, it is necessary to define the amount of free radicals of pheomelanin in red hair using ESR spectroscopy method. Besides, it is very important to find effective antioxidant, capable of neutralizing free radicals of pheomelanin. It was proved that ascorbic acid neutralizes free radicals of pheomelanin very effectively. The main goal of our research was to define the presumably optimal concentration of ascorbic acid as an antioxidant and study the kinetics of the influence of this concentration on red and black hair. It has been found out, that ascorbic acid influences the free radicals of red and black hair, and its appropriate optimal concentration is 10 mM. The obtained results can be considered in dermatology and cosmetology.

  3. Improved FIA-ABTS method for antioxidant capacity determination in different biological samples.

    Science.gov (United States)

    Bompadre, Stefano; Leone, Luciana; Politi, Alessia; Battino, Maurizio

    2004-08-01

    In order to evaluate the actual antioxidant features of foods, beverages and also plasma from patients, a number of assays have been developed in the last few years to determine the so called total antioxidant activity (TAA), intended as the cumulative capacity of a biological sample to scavenge free radicals. Most of the assays partially failed in obtaining a good reproducibility when using plasma because it is composed of a large number of substances, some of which are present at very high concentrations and possess masking features. For these reasons we have improved the widely known ABTS method by means of a FIA system where both temperature and dispersion of sample and reagent were strictly controlled. We found that temperature may be a critical aspect in the measurement of plasma TAA whilst its influence may be less important in the assay of non-complex biological samples. We demonstrated that also the reaction time may be critical, depending on the nature of the substance employed. Data confirmed the high TAA of a methylsalicylate-containing mouthrinse as well as the negligible TAA offered by the chlorhexidine containing one. White wines (Verdicchio) also displayed interesting TAA values. The improved method was useful to screen rapidly, without dilution, with very limited handling of the sample and with high repeatability the TAA of plasma in addition to chemical products, beverages and non-complex biological mixtures.

  4. Generation of counter ion radical (Br2(•-)) and its reactions in water-in-oil (CTAB or CPB)/n-butanol/cyclohexane/water) microemulsion.

    Science.gov (United States)

    Guleria, Apurav; Singh, Ajay K; Sarkar, Sisir K; Mukherjee, Tulsi; Adhikari, Soumyakanti

    2011-09-15

    Herein we report the generation of counterion radicals and their reactions in quaternary water-in-oil microemulsion. Hydrated electrons in the microemulsion CTAB/H(2)O/n-butanol/cyclohexane have a remarkably short half-life (∼1 μs) and lower yield as compared to that in the pure water system. Electrons are solvated in two regions: one is the water core and other the interface; however, the electrons in the water core have a shorter half-life than those in the interface. The decay of the solvated electrons in the interface is found to be water content dependent and it has been interpreted in terms of increased interfacial fluidity with the increase in water content of the microemulsion. Interestingly another species, dibromide radical anion (Br(2)(•-)) in CTAB and CPB microemulsions have been observed after the electron beam irradiation. Assuming that the extinction coefficient of the radicals is the same as that in the aqueous solution, the yields of the radicals per 100 eV are 0.29 and 0.48 for the Br(2)(•-) radical in CTAB and CPB containing microemulsions (W(0) = 40), respectively, under N(2)O saturated conditions. Further, we intended to study electron transfer reactions, which occur at and through the interface. The reaction of the Br(2)(•-) radical anion with ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] has been studied to generate the ABTS radical in the water core, and further, its reaction has been investigated with the water-insoluble molecule vitamin E (tocopherol) and water-soluble vitamin C (ascorbic acid). In the present study, we were able to show that, even for molecules which are completely insoluble in water, ABTS scavenging assay is possible by pulse radiolysis technique. Furthermore, these results show that it is possible to follow the reaction of the hydrated inorganic radical with solutes dissolved in the organic phase in a microemulsion without use of a phase transfer catalyst.

  5. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  6. Arylperoxyl radicals. Formation, absorption spectra, and reactivity in aqueous alcohol solutions

    Energy Technology Data Exchange (ETDEWEB)

    Alfassi, Z.B.; Khaikin, G.I.; Neta, P. (National Inst. of Standards and Technology, Gaithersburg, MD (United States))

    1995-01-05

    Aryl radicals (phenyl, 4-biphenylyl, 2-naphthyl, 1-naphthyl, and 9-phenanthryl) were produced by the reaction of the corresponding aryl bromide with solvated electrons and reacted rapidly with oxygen to produce the arylperoxyl radicals. These radicals exhibit optical absorptions in the visible range, with [lambda][sub max] at 470, 550, 575, 650, and 700 nm, respectively. Arylperoxyl radicals react with 2,2[prime]-azinobis(3-ethylbenzothiazoiine-6-sulfonate ion) (ABTS), chlorpromazine, and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox C) by one-electron oxidation. The rate constants k for these reactions, determined from the rate of formation of the one-electron oxidation products as a function of substrate concentration, vary between 4 [times] 10[sup 6] and 2 [times] 10[sup 9] L mol[sup [minus]1] s[sup [minus]1] and increase in the order phenyl-, 4-biphenyl-, 2-naphthyl-, 1-naphthyl-, and 9-phenanthrylperoxyl, the same order as the absorption peaks of these radicals. Good correlation was found between log k and the energy of the absorption peak. 16 refs., 2 figs., 2 tabs.

  7. Free radical grafting of gallic acid (GA) on cellulose nanocrystals (CNCS) and evaluation of antioxidant reinforced gellan gum films

    Science.gov (United States)

    Criado, P.; Fraschini, C.; Salmieri, S.; Becher, D.; Safrany, A.; Lacroix, M.

    2016-01-01

    Antiradical properties were introduced on cellulose nanocrystals (CNCs) by redox pair (RP) initiator and γ-radiation treatments. Different procedures were tested on CNC, first a 2 h reaction of hydrogen peroxide (H2O2)/ascorbic acid (AA) was performed on CNC solution. γ-Radiation treatment at 20 kGy dose was then applied and immediately after GA was reacted during 24 h with the pretreated CNCs, giving CNC-H2O2-AA-γ-GA. The formation of new carboxylic acids and carbonyl groups were characterized by FT-IR at 1650 and 1730 cm-1 respectively. Carboxylic acid functionalities were also analyzed by conductometric titration where an increase from 49 to 134 mmol COOH kg-1 was found from native to irradiated CNCs. A similar increase in the carboxylic acid content (132 mmol kg-1) was observed for CNC-H2O2-AA-γ-GA, showing the highest radical scavenging properties (8 mM Trolox eq/mg CNC). Thermogravimetric analysis confirmed the structural changes onto CNC. Film packaging containing 20% of CNC-H2O2-AA-γ-GA was then added to a gellan-based film packaging. A significant improvement (p<0.05) of the tensile strength (TS), the tensile modulus (TM) and the elongation at break (EB) and water vapor permeability reduction was observed when CNC-H2O2-AA-γ-GA was added to the film packaging formulation.

  8. In-vitro free radical scavenging activity of biosynthesized gold and silver nanoparticles using Prunus armeniaca (apricot) fruit extract

    Energy Technology Data Exchange (ETDEWEB)

    Dauthal, Preeti; Mukhopadhyay, Mausumi, E-mail: mausumi_mukhopadhyay@yahoo.com [S.V. National Institute of Technology, Department of Chemical Engineering (India)

    2013-01-15

    In-vitro free radical scavenging activity of biosynthesized gold (Au-NPs) and silver (Ag-NPs) nanoparticles was investigated in the present study. Natural precursor Prunus armeniaca (apricot) fruit extract was used as a reducing agent for the nanoparticle synthesis. The free radical scavenging activity of the nanoparticles were observed by modified 1,1 Prime -diphynyl-2-picrylhydrazyl, DPPH and 2,2 Prime -azinobis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS assay. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy, and fourier transform infrared spectroscopy (FTIR). Appearance of optical absorption peak at 537 nm (2.20 keV) and 435 nm (3 keV) within 0.08 and 0.5 h of reaction time was confirmed the presence of metallic Au and Ag nanoclusters, respectively. Nearly spherical nanoparticles with majority of particle below 20 nm (TEM) for both Au-NPs and Ag-NPs were synthesized. XRD pattern confirmed the existence of pure nanocrystalline Au-NPs while few additional peaks in the vicinity of fcc silver-speculated crystallization of metalloproteins of fruit extract on the surface of the Ag-NPs and vice versa. FTIR spectra was supported the role of amino acids of protein/enzymes of fruit extract for synthesis and stabilization of nanoparticles. Dose-dependent scavenging activity was observed for Au-NPs and Ag-NPs in both DPPH and ABTS in-vitro assay. 50 % scavenging activity for DPPH were 11.27 and 16.18 mg and for ABTS 3.40 and 7.12 mg with Au-NPs and Ag-NPs, respectively.

  9. In-vitro free radical scavenging activity of biosynthesized gold and silver nanoparticles using Prunus armeniaca (apricot) fruit extract

    Science.gov (United States)

    Dauthal, Preeti; Mukhopadhyay, Mausumi

    2013-01-01

    In-vitro free radical scavenging activity of biosynthesized gold (Au-NPs) and silver (Ag-NPs) nanoparticles was investigated in the present study. Natural precursor Prunus armeniaca (apricot) fruit extract was used as a reducing agent for the nanoparticle synthesis. The free radical scavenging activity of the nanoparticles were observed by modified 1,1'-diphynyl-2-picrylhydrazyl, DPPH and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS assay. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy, and fourier transform infrared spectroscopy (FTIR). Appearance of optical absorption peak at 537 nm (2.20 keV) and 435 nm (3 keV) within 0.08 and 0.5 h of reaction time was confirmed the presence of metallic Au and Ag nanoclusters, respectively. Nearly spherical nanoparticles with majority of particle below 20 nm (TEM) for both Au-NPs and Ag-NPs were synthesized. XRD pattern confirmed the existence of pure nanocrystalline Au-NPs while few additional peaks in the vicinity of fcc silver-speculated crystallization of metalloproteins of fruit extract on the surface of the Ag-NPs and vice versa. FTIR spectra was supported the role of amino acids of protein/enzymes of fruit extract for synthesis and stabilization of nanoparticles. Dose-dependent scavenging activity was observed for Au-NPs and Ag-NPs in both DPPH and ABTS in-vitro assay. 50 % scavenging activity for DPPH were 11.27 and 16.18 mg and for ABTS 3.40 and 7.12 mg with Au-NPs and Ag-NPs, respectively.

  10. Oxygen acidity of ring methoxylated 1,1-diarylalkanol radical cations bearing alpha-cyclopropyl groups. The competition between O-neophyl shift and C-cyclopropyl beta-scission in the intermediate 1,1-diarylalkoxyl radicals.

    Science.gov (United States)

    Bietti, Massimo; Fiorentini, Simone; Pato, Iria Pèrez; Salamone, Michela

    2006-04-14

    A product and time-resolved kinetic study on the reactivity of the radical cations generated from cyclopropyl(4-methoxyphenyl)phenylmethanol (1) and cyclopropyl[bis(4-methoxyphenyl)]methanol (2) has been carried out in aqueous solution. In acidic solution, 1*+ and 2*+ display very low reactivities toward fragmentation, consistent with the presence of groups at Calpha (aryl and cyclopropyl) that after Calpha-Cbeta bond cleavage would produce relatively unstable carbon-centered radicals. In basic solution, 1*+ and 2*+ display oxygen acidity, undergoing -OH-induced deprotonation from the alpha-OH group, leading to the corresponding 1,1-diarylalkoxyl radicals 1r* and 2r*, respectively, as directly observed by time-resolved spectroscopy. The product distributions observed in the reactions of 1*+ and 2*+ under these conditions (cyclopropyl phenyl ketone, cyclopropyl(4-methoxyphenyl) ketone, and 4-methoxybenzophenone from 1*+; cyclopropyl(4-methoxyphenyl) ketone and 4,4'-dimethoxybenzophenone from 2*+) have been rationalized in terms of a water-induced competition between O-neophyl shift and C-cyclopropyl beta-scission in the intermediate 1,1-diarylalkoxyl radicals 1r* and 2r*.

  11. Highly selective capture of nucleosides with boronic acid functionalized polymer brushes prepared by atom transfer radical polymerization.

    Science.gov (United States)

    Cheng, Ting; Zhu, Shuqiang; Zhu, Bin; Liu, Xiaoyan; Zhang, Haixia

    2016-04-01

    The nucleoside or modified nucleoside level in biological fluids reflects the pathological or physiological state of the body. Boronate affinity absorbents are widely used to selectively extract nucleosides from complex samples. In this work, a novel functionalized absorbent was synthesized by attaching 4-mercaptophenylboronic acid to gold nanoparticles on modified attapulgite. The surface of the attapulgite was modified by poly(acryloyloxyethyltrimethyl ammonium chloride) by atom transfer radical polymerization, creating many polymer brushes on the surface. The resultant material exhibited superior binding capacity (30.83 mg/g) for adenosine and was able to capture cis-diol nucleosides from 1000-fold interferences. Finally, to demonstrate its potential for biomolecule extraction, this boronate affinity material was used to preconcentrate nucleosides from human urine and plasma.

  12. Maesa indica: a nutritional wild berry rich in polyphenols with special attention to radical scavenging and inhibition of key enzymes, α-amylase and α-glucosidase.

    Science.gov (United States)

    Shanmugam, Saravanan; Baby, John Prakash; Chandran, Rahul; Thankarajan, Sajeesh; Thangaraj, Parimelazhagan

    2016-07-01

    The present study was aimed to evaluate the nutritional, antioxidant properties and inhibition of the key enzyme such as α-amylase and α-glucosidase from the fruits of Maesa indica. The results revealed that M. indica fruits possess an enormous amount of protein (45.68 mg/g), carbohydrates (25.12 mg/g) and mineral elements. The acetone extract were capable of hunting radicals by providing electrons and break chain reaction, especially in ABTS(·+) (3719.23 µmol TE/g extract), OH(·) (66.50 %) and NO(·) (81.50 %) radical scavenging assays. The methanol extract showed a strong inhibition towards α-amylase and α-glucosidase (IC50 of 37.80 and 23.74 µg/mL, respectively). HPLC analysis enumerate that both extracts illustrates the presence of polyphenolic compounds namely quercetin, caffeic acid, rutin and chlorogenic acid.

  13. 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.

  14. AVALIAÇÃO DO RADICAL N,N-DIETIL-1,4-FENILENODIAMINO (DEPD•+ COMO SONDA ESPECTROFOTOMÉTRICA PARA DETERMINAÇÃO DA CAPACIDADE ANTIOXIDANTE EM BEBIDAS

    Directory of Open Access Journals (Sweden)

    Rosicleide Viturina dos Santos

    2015-08-01

    Full Text Available AbstractMany well-established methods for determining the antioxidant capacities in several samples have been described in literature. However, DPPH (2,2-diphenyl-1-picrylhydrazyl and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid are the main two methods that utilize radicals as spectrophotometric probes for analysis. Nevertheless, these methods have certain limitations because of their slower kinetics, solvent polarity effects, the hydrophilicity and lipophilicity of the compounds, chemical costs, etc. In this study, a spectrophotometric method for determining the antioxidant capacity in beverages was developed based on an exploration of the cation radical derived from DEPD. This method was based on the oxidation of aromatic amines with Fe(III ions at pH 4.0, which leads to their corresponding purple cation radicals (DEPD•+ with λmax values at 500 and 540 nm. The addition of an antioxidant after the formation of the radical leads to a reduction in color intensity that is proportional to the antioxidant concentration in the medium. Results obtained using this method were compared with the Folin-Ciocalteau, ABTS and DPPH methods in terms of applications in wines, teas, and infusions samples. Linear correlation analysis at a 95% confidence level was employed to compare the results, which were in good agreement with a correlation coefficient of r > 0.9000. Thus, the developed method was simple, accurate, and consistent with other assays for the determination of the total amount of phenolic compounds and antioxidant capacity.

  15. Combined microplate-ABTS and HPLC-ABTS analysis of tomato and pepper extracts reveals synergetic and antagonist effects of their lipophilic antioxidative components.

    Science.gov (United States)

    Le Grandois, Julie; Guffond, Delphine; Hamon, Erwann; Marchioni, Eric; Werner, Dalal

    2017-05-15

    The antioxidant capacity of 9 pure lipophilic compounds was examined by microplate-ABTS and HPLC-ABTS, using similar experimental conditions. Results obtained showed that HPLC-ABTS method can be used for a rapid determination of individual antioxidant capacity of compounds in standard solutions or complex mixtures. The application of both methods to real lipophilic extracts from tomato (Solanum lycopersicum L.), green and red peppers (Capsicum annuum) reveals possible interactions between antioxidants. Thus, synthetic mixtures of two compounds identified in tomato and peppers were measured using microplate-ABTS and HPLC-ABTS. Synergistic effects were observed between (β-carotene-capsanthin) (1:9) and (1:1), (α-tocopherol-capsanthin) (1:9), (lutein-lycopene) (9:1) and (capsanthin-δ-tocopherol) (9:1). On the contrary, antagonistic effects were observed for (lutein-δ-tocopherol) and (α-tocopherol-δ-tocopherol). The interactions observed with two-compound mixtures are not systematically observed in the natural lipophilic extracts from tomato, green and red peppers, probably since extracts are more complex and are susceptible to cause interferences.

  16. ABTS-modified multiwalled carbon nanotubes as an effective mediating system for bioelectrocatalytic reduction of oxygen.

    Science.gov (United States)

    Karnicka, Katarzyna; Miecznikowski, Krzysztof; Kowalewska, Barbara; Skunik, Magdalena; Opallo, Marcin; Rogalski, Jerzy; Schuhmann, Wolfgang; Kulesza, Pawel J

    2008-10-01

    The ability of such a common redox mediator as 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) to undergo sorption on carbon surfaces is explored here to convert multiwalled carbon nanotubes (CNTs) into a stable colloidal solution of ABTS-modified carbon nanostructures, the diameters of which are approximately 10 nm (as determined by transmission electron microscopy). Subsequently, inks composed of fungal laccase (Cerrena unicolor) mixed with the dispersion of ABTS-modified CNTs and stabilized with Nafion, were deposited on glassy carbon and successfully employed to the reduction of oxygen in McIlvain buffer at pH 5.2. For comparison, the systems utilizing only ABTS-free CNTs and laccase as well as ABTS-modified CNTs did not show appreciable activity toward the oxygen reduction. The three-dimensionally distributed ABTS-modified CNTs are expected to improve the film's overall conductivity and to facilitate electrical connection between the electrode and the enzyme. The network film of ABTS-modified CNTs is rigid, and it is characterized by charge propagation capabilities comparable to the conventional redox polymers. The whole concept of utilization of CNTs modified with ultrathin films of redox mediators in the preparation of efficient bioelectrocatalytic films seems to be of general importance to electroanalytical chemistry and to the development of biosensors.

  17. ABT-737, a Bcl-2 Selective Inhibitor, and Chloroquine Synergistically Kill Renal Cancer Cells.

    Science.gov (United States)

    Yin, Pei; Jia, Jinpeng; Li, Jijun; Song, Yan; Zhang, Yiyan; Chen, Fengkun

    2016-01-01

    Renal cell carcinoma (RCC) is the most common malignancy in the kidney in the world, and the 5-year overall survival for patients remains poor due to the lack of effective treatment strategies. Although ABT-737, as a Bcl-2/Bcl-xL inhibitor, has recently emerged as a novel cancer therapeutic reagent, apoptosis induced by ABT-737 is often blocked in several types of cancer cells. This study investigated whether the combination of the small-molecule BH3 mimetic ABT-737 and the lysosome inhibitor chloroquine was an effective strategy for treating renal cancer cells. We found that the combination of ABT-737 and chloroquine synergistically decreased cell viability when compared to treatment with either single reagent. Cell apoptosis induced by a combined treatment was markedly inhibited by the caspase inhibitors z-DEVD-FMK and z-VAD-FMK. It was also inhibited by cathepsin inhibitor E-64 and CTSI (cathepsin inhibitor), which suggested that apoptosis was dependent on the cascade of caspase activation and cathepsins released from lysosomes. Furthermore, we found that ABT-737 could increase the cell level of ROS, which triggers cathepsin-mediated cell death and augments the role of chloroquine in cell death. So the combination of ABT-737 and chloroquine was an effective strategy for the treatment of renal cancer cells, and this combined strategy may widen the therapeutic window of ABT-737 and chloroquine as well as enhance the clinical efficacy of synergistic drug combinations.

  18. Granulocyte colony-stimulating factor increases extracellular glutamic acid uptake and suppresses free radicals in an experimental model of amyotrophic lateral sclerosis

    Institute of Scientific and Technical Information of China (English)

    Shengzhe Zheng; Lei Song; Lei Lu; Lina Lin; Yao Wang; Qun Liu

    2011-01-01

    Excitatory amino acid toxicity and free radical damage play important roles in amyotrophic lateral sclerosis.Granulocyte colony-stimulating factor (G-CSF) protects nerve cells exposed to high-concentrations of glutamic acid, suggesting positive effects in the treatment of amyotrophic lateral sclerosis.The present study induced in vitro motor neuron injury using glutamic acid excitotoxicity, and the biochemical effects of G-CSF on glutamic acid concentration were determined.In addition, the effects of G-CSF on superoxide dismutase, glutathione peroxidase activity in motor neurons, and malondialdehyde and nitric oxide contents were analyzed.Immunohistochemistry was performed to measure neuronal survival.Results revealed that G-CSF significantly suppressed free radical activity, inhibited excitotoxicity, and reduced apoptosis and loss of motor neurons in the anterior horn of the spinal cord.

  19. Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids.

    Directory of Open Access Journals (Sweden)

    Juan José Dorantes-Aranda

    Full Text Available Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum. Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35% and also the major producer of superoxide radicals (14 pmol cell-1 hr-1 especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1. Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content, respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 μg mL-1 and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1 could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability, whereas

  20. Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids.

    Science.gov (United States)

    Dorantes-Aranda, Juan José; Seger, Andreas; Mardones, Jorge I; Nichols, Peter D; Hallegraeff, Gustaaf M

    2015-01-01

    Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35%) and also the major producer of superoxide radicals (14 pmol cell-1 hr-1) especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1). Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD) and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content), respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 μg mL-1) and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1) could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST) GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability), whereas crude

  1. Antioxidant and DPPH (1,1-diphenyl-2-picrylhydrazyl Free Radical Scavenging Activities of Boniger Acid and Calix[4]arene Derivative

    Directory of Open Access Journals (Sweden)

    E. ERDEM

    2014-07-01

    Full Text Available Diazonium derivative of calix[4]arene has been synthesized using three different synthetic steps. Initially p-tert-butylcalix[4]arene was synthesized with the condensation reaction of p-tert-butylphenol and formaldehyde in basic conditions. Calix[4]arene was obtained after the debutylation reaction of p-tert-butylcalix[4]arene with AlCl3. Calix[4]arene reacted with diazonium salt of Böniger acid to yield the 5,17-[(Bis(azo-bis(5-hydroxy-2,7-naphthalenedisulfonicacid]-25,26,27,28-tetrahydroxy calix[4]arene which has eight free phenolic hydroxyl group. Reaction steps were shown in Fig.1.2,7-naphthalenedisulfonicacid]-25,26,27,28-tetrahydroxy calix[4]arene The antioxidant activity of the Böniger acid and calix[4]aren derivative were determined using β-karotene-linoleic acid system. Moreover, the free radical scavenging activity values were tested with DPPH free radical. The two compounds showed strong antioxidant activity. Total antioxidant activity of Böniger acid and calix[4]aren derivative was determined using β–carotenelinoleic acid model system and was found the antioxidant activity of 84.00% and 85.60 % respectively. The free radical scavenging activities were determined as 83.05% and 84.69 %. Results show that, two compounds has the antioxidant activity. The calix[4]aren derivaties has more higher activity then Boniger acid because of calix[4]aren derivative has much hydroxl groups.

  2. Antioxidant activity of a salt-spice-herbal mixture against free radical induction.

    Science.gov (United States)

    Natarajan, Kavithalakshmi S; Narasimhan, Madhusudhanan; Shanmugasundaram, K Radha; Shanmugasundaram, E R B

    2006-04-21

    A combination of spices (Piper nigrum, Piper longum and Zingiber officinale), herbs (Cyperus rotundus and Plumbago zeylanica) and salts make up Amrita Bindu. The study was focused to evaluate the antioxidant property of individual ingredients in Amrita Bindu against the free radical 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The analysis revealed the antioxidant potential of the ingredients in the following order: Piper nigrum>Piper longum>Cyperus rotundus>Plumbago zeylanca>Zingiber officinale. Two different experiments were designed. In experiment I, rats were fed with normal diet whereas in experiment II rats were given feed mixed with Amrita Bindu for 3 weeks (4 g/kg of feed). Rats from both experimental groups were challenged against a single intraperitonial injection of phenylhydrazine (PHZ) (7.5 mg/kg body weight). At the end of 24 and 72 h, blood was analysed for free radicals and antioxidant levels. It was interesting to note that rats with Amrita Bindu pretreatment showed significantly lower levels of free radicals, lipid peroxidation and protein carbonyls along with significantly higher levels of antioxidants when compared with rats without Amrita Bindu pretreatment on PHZ administration. These results reveal that Amrita Bindu, a salt-spice-herbal mixture exerts a promising antioxidant potential against free radical induced oxidative damage.

  3. The action of peroxyl radicals, powerful deleterious reagents, explains why neither cholesterol nor saturated fatty acids cause atherogenesis and age-related diseases.

    Science.gov (United States)

    Spiteller, Gerhard; Afzal, Mohammad

    2014-11-10

    Cells respond to alterations in their membrane structure by activating hydrolytic enzymes. Thus, polyunsaturated fatty acids (PUFAs) are liberated. Free PUFAs react with molecular oxygen to give lipid hydroperoxide molecules (LOOHs). In case of severe cell injury, this physiological reaction switches to the generation of lipid peroxide radicals (LOO(·)). These radicals can attack nearly all biomolecules such as lipids, carbohydrates, proteins, nucleic acids and enzymes, impairing their biological functions. Identical cell responses are triggered by manipulation of food, for example, heating/grilling and particularly homogenization, representing cell injury. Cholesterol as well as diets rich in saturated fat have been postulated to accelerate the risk of atherosclerosis while food rich in unsaturated fatty acids has been claimed to lower this risk. However, the fact is that LOO(·) radicals generated from PUFAs can oxidize cholesterol to toxic cholesterol oxides, simulating a reduction in cholesterol level. In this review it is shown how active LOO(·) radicals interact with biomolecules at a speed transcending usual molecule-molecule reactions by several orders of magnitude. Here, it is explained how functional groups are fundamentally transformed by an attack of LOO(·) with an obliteration of essential biomolecules leading to pathological conditions. A serious reconsideration of the health and diet guidelines is required.

  4. A Metal and Base-Free Chemoselective Primary Amination of Boronic Acids Using Cyanamidyl/Arylcyanamidyl Radical as Aminating Species: Synthesis and Mechanistic Studies by Density Functional Theory.

    Science.gov (United States)

    Chatterjee, Nachiketa; Arfeen, Minhajul; Bharatam, Prasad V; Goswami, Avijit

    2016-06-17

    An efficient, metal and base-free, chemoselective synthesis of aryl-, heteroaryl-, and alkyl primary amines from the corresponding boronic acids has been achieved at ambient temperature mediated by [bis(trifluoroacetoxy)iodo]benzene (PIFA) and N-bromosuccinimide (NBS) using cyanamidyl/arylcyanamidyl radicals as the aminating species. The primary amine compounds were initially obtained as their corresponding ammonium trifluoroacetate salts which, on treatment with aq NaOH, provide the free amines. Finally, the primary amines were isolated through column chromatography over silica-gel using hexane-EtOAc solvent system as the eluent. The reactions are sufficiently fast, completing within 1 h. Quantum chemical calculations in combination with experimental observations validate that the ipso amination of substituted boronic acids involves the formation of cyanamidyl/arylcyanamidyl radical, followed by regiospecific interaction of its nitrile-N center with boron atom of the boronic acids, leading to chemoselective primary amination.

  5. Evaluation of Concurrent Radiation, Temozolomide and ABT-888 Treatment Followed by Maintenance Therapy with Temozolomide and ABT-888 in a Genetically Engineered Glioblastoma Mouse Model

    Directory of Open Access Journals (Sweden)

    Benjamin Lemasson

    2016-02-01

    Full Text Available Despite the use of ionizing radiation (IR and temozolomide (TMZ, outcome for glioblastoma (GBM patients remains dismal. Poly (ADP-ribose polymerase (PARP is important in repair pathways for IR-induced DNA damage and TMZ-induced alkylation at N7-methylguanine and N3-methyldenine. However, optimized protocols for administration of PARP inhibitors have not been delineated. In this study, the PARP inhibitor ABT-888 was evaluated in combination with and compared to current standard-of-care in a genetically engineered mouse GBM model. Results demonstrated that concomitant TMZ/IR/ABT-888 with adjuvant TMZ/ABT-888 was more effective in inducing apoptosis and reducing proliferation with significant tumor growth delay and improved overall survival over concomitant TMZ/IR with adjuvant TMZ. Diffusion-weighted MRI, an early translatable response biomarker detected changes in tumors reflecting response at 1 day post TMZ/IR/ABT-888 treatment. This study provides strong scientific rationale for the development of an optimized dosing regimen for a PARP inhibitor with TMZ/IR for upfront treatment of GBM.

  6. Evaluation of Concurrent Radiation, Temozolomide and ABT-888 Treatment Followed by Maintenance Therapy with Temozolomide and ABT-888 in a Genetically Engineered Glioblastoma Mouse Model.

    Science.gov (United States)

    Lemasson, Benjamin; Wang, Hanxiao; Galbán, Stefanie; Li, Yinghua; Zhu, Yuan; Heist, Kevin A; Tsein, Christina; Chenevert, Thomas L; Rehemtulla, Alnawaz; Galbán, Craig J; Holland, Eric C; Ross, Brian D

    2016-02-01

    Despite the use of ionizing radiation (IR) and temozolomide (TMZ), outcome for glioblastoma (GBM) patients remains dismal. Poly (ADP-ribose) polymerase (PARP) is important in repair pathways for IR-induced DNA damage and TMZ-induced alkylation at N7-methylguanine and N3-methyldenine. However, optimized protocols for administration of PARP inhibitors have not been delineated. In this study, the PARP inhibitor ABT-888 was evaluated in combination with and compared to current standard-of-care in a genetically engineered mouse GBM model. Results demonstrated that concomitant TMZ/IR/ABT-888 with adjuvant TMZ/ABT-888 was more effective in inducing apoptosis and reducing proliferation with significant tumor growth delay and improved overall survival over concomitant TMZ/IR with adjuvant TMZ. Diffusion-weighted MRI, an early translatable response biomarker detected changes in tumors reflecting response at 1 day post TMZ/IR/ABT-888 treatment. This study provides strong scientific rationale for the development of an optimized dosing regimen for a PARP inhibitor with TMZ/IR for upfront treatment of GBM.

  7. EPR study of the astaxanthin n-octanoic acid monoester and diester radicals on silica-alumina.

    Science.gov (United States)

    Focsan, A Ligia; Bowman, Michael K; Shamshina, Julia; Krzyaniak, Matthew D; Magyar, Adam; Polyakov, Nikolay E; Kispert, Lowell D

    2012-11-08

    The radical intermediates of the n-octanoic monoester and n-octanoic diester of astaxanthin were detected by pulsed EPR measurements carried out on the UV-produced radicals on silica-alumina artificial matrix and characterized by density functional theory (DFT) calculations. Previous Mims ENDOR for astaxanthin detected the radical cation and neutral radicals formed by proton loss from the C3 (or C3') position and from the methyl groups. Deprotonation of the astaxanthin neutral radical formed at the C3 (or C3') position resulted in a radical anion. DFT calculations for astaxanthin showed that the lowest energy neutral radical forms by proton loss at the C3 (or C3') position of the terminal ring followed by proton loss at the methyl groups of the polyene chain. Contrary to astaxanthin where proton loss can occur at either end of the symmetrical radical, for the diester of astaxanthin, this loss is prevented at the cyclohexene ends and is favored for its methyl groups. The monoester of astaxanthin, however, allows formation of the neutral radical at C3' and prevents its formation at the opposite end where the ester group is attached. At the terminal ring without the ester group attached, migration of proton from hydroxyl group to carbonyl group facilitates resonance stabilization, similarly to already published results for astaxanthin. However, cw EPR shows no evidence of a monoester radical anion formed. This study suggests the different radicals of astaxanthin and its esters that would form in a preferred environment, either hydrophobic or hydrophilic, depending on their structure.

  8. CBLB502, an agonist of Toll-like receptor 5, has antioxidant and scavenging free radicals activities in vitro.

    Science.gov (United States)

    Li, Weiguang; Ge, Changhui; Yang, Liu; Wang, Ruixue; Lu, Yiming; Gao, Yan; Li, Zhihui; Wu, Yonghong; Zheng, Xiaofei; Wang, Zhaoyan; Zhang, Chenggang

    2016-01-01

    The bacterial protein flagellin is the known agonist of Toll-like receptor 5 (TLR5). It has been reported that CBLB502, a novel agonist of TLR5 derived from Salmonella flagellin, could reduce radiation toxicity in mouse and primate models, protect mice from dermatitis and oral mucositis caused by radiation, inhibit acute renal ischemic failure, and inhibit the growth of A549 lung cancer cell. The property of CBLB502 is able to bind to TLR5 and activates NF-κB signaling. In this study, we investigated the antioxidant potential and free radicals scavenging properties of CBLB502 in vitro. Interestingly, we found that CBLB502 has a direct and distinct antioxidant capacity and can efficiently scavenge a variety of free radicals, including superoxide anion, hydroxyl radical, and ABTS cation (ABTS(+)). Through wave scanning and kinetic evaluation of scavenging ABTS(+), we found that the ABTS(+) scavenging process of CBLB502 is relatively slow, and the ABTS(+) scavenging activity of CBLB502 has a consistently kinetics characteristics. In conclusion, our results suggested that CBLB502 has antioxidant and scavenging free radicals activities in vitro. It is implied that CBLB502 might partially promote the beneficial protective effect through its scavenging free radicals.

  9. Metabolism and disposition of ABT-894, a novel α4β2 neuronal acetylcholine receptor agonist, in mice and monkeys.

    Science.gov (United States)

    Liu, Hong; Fu, Wentao; Wetter, Jill; Xu, Hongyu; Guan, Zhiwen; Stuart, Patricia

    2014-06-01

    1.  Metabolism and disposition of ABT-894 was investigated in hepatocytes, in mice and monkeys receiving [(14)C]ABT-894. 2.  In hepatocytes, turnover rate of ABT-894 was slow in all species with more than 90% of parent remaining. M3 (carbamoyl glucuronide) and M6 (mono-oxidation) were detected across species. 3.  ABT-894 showed species-specific disposition profiles. ABT-894 was primarily eliminated by renal secretion in mice. Whereas, monkey mainly cleared ABT-894 metabolically. 4.  ABT-894 underwent two primary routes of metabolism in monkeys: N-carbamoyl glucuronidation to form M3 and oxidation product M1. M3 was the major metabolite in monkey excreta. M3 was observed in mice urine. Circulating levels of M3 in terms of M3/ABT-894 ratios were essentially absent in mice, but were high in monkeys. 5.  Understanding the species difference in the clearance mechanism is the key to the accurate projection of the human clearance and preclinical safety assessment. Lack of species difference in the metabolism of ABT-894 in hepatocytes certainly creates a challenge in predicting its metabolism and pharmacokinetics in human. Based on available metabolism and pharmacokinetic data of ABT-894 in human, monkey is the preferred species in predicting human clearance since it presents a similar clearance mechanism from that observed in human.

  10. Time-resolved EPR investigation of potential model systems for acrylate polymer main chain radicals based on esters of Kemp's tri-acid.

    Science.gov (United States)

    Lebedeva, Natalia V; Gorelik, Elena V; Magnus-Aryitey, Damaris; Hill, Terence E; Forbes, Malcolm D E

    2009-05-14

    Methyl esters of Kemp's tri-acid and cyclohexanetricarboxylic acid are structurally similar to acrylate polymers, having the same functionalities and stereoregularities as poly(methylmethacrylate) and poly(methylacrylate), respectively. The photochemistry and free radicals from these model systems have been studied using time-resolved electron paramagnetic resonance spectroscopy with laser flash photolysis at 248 nm. Chemically induced electron spin polarization from the triplet mechanism (net emission) is observed. Well-resolved spectra are obtained at all temperatures for the model system radicals, which are determined to be in the slow motion condition, that is, there is no interconversion of chair conformations. The temperature dependence of the spectra is minimal; some hyperfine lines shift as the temperature increases, but without much broadening. Density functional theory calculations are presented and discussed in support of the experimental data.

  11. Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006

    Directory of Open Access Journals (Sweden)

    B. H. Czader

    2012-08-01

    Full Text Available Nitrous acid (HONO mixing ratios for the Houston metropolitan area were simulated with the Community Multiscale Air Quality (CMAQ Model for an episode during the Texas Air Quality Study (TexAQS II in August/September 2006 and compared to in-situ MC/IC (mist-chamber/ion chromatograph and long path DOAS (Differential Optical Absorption Spectroscopy measurements at three different altitude ranges. Several HONO sources were accounted for in simulations, such as gas phase formation, direct emissions, nitrogen dioxide (NO2 hydrolysis, photo-induced formation from excited NO2 and photo-induced conversion of NO2 into HONO on surfaces covered with organic materials. Compared to the gas-phase HONO formation there was about a tenfold increase in HONO mixing ratios when additional HONO sources were taken into account, which improved the correlation between modeled and measured values. Concentrations of HONO simulated with only gas phase chemistry did not change with altitude, while measured HONO concentrations decrease with height. A trend of decreasing HONO concentration with altitude was well captured with CMAQ predicted concentrations when heterogeneous chemistry and photolytic sources of HONO were taken into account. Heterogeneous HONO production mainly accelerated morning ozone formation, albeit slightly. Also HONO formation from excited NO2 only slightly affected HONO and ozone (O3 concentrations. Photo-induced conversion of NO2 into HONO on surfaces covered with organic materials turned out to be a strong source of daytime HONO. Since HONO immediately photo-dissociates during daytime its ambient mixing ratios were only marginally altered (up to 0.5 ppbv, but significant increase in the hydroxyl radical (OH and ozone concentration was obtained. In contrast to heterogeneous HONO formation that mainly accelerated morning ozone formation, inclusion of photo-induced surface chemistry

  12. Modeling nitrous acid and its impact on ozone and hydroxyl radical during the Texas Air Quality Study 2006

    Directory of Open Access Journals (Sweden)

    B. H. Czader

    2012-02-01

    Full Text Available Nitrous acid (HONO mixing ratios for the Houston metropolitan area were simulated with the Community Multiscale Air Quality (CMAQ model for an episode during the Texas Air Quality Study (TexAQS II in August/September 2006 and compared to in-situ MC/IC (mist-chamber/ion chromatograph and long path DOAS (Differential Optical Absorption Spectroscopy measurements at three different altitudes. Several HONO sources were accounted for in simulations, such as gas phase formation, direct emissions, nitrogen dioxide (NO2* hydrolysis, photo-induced formation from excited NO2* and photo-induced conversion of NO2 into HONO on surfaces covered with organic materials. Compared to the gas-phase HONO formation there was about a tenfold increase in HONO mixing ratios when additional HONO sources were taken into account, which improved the correlation between modeled and measured values. Concentrations of HONO simulated with only gas phase chemistry did not change with altitude, while measured HONO concentrations decrease with height. A trend of decreasing HONO concentration with altitude was well captured with CMAQ predicted concentrations when heterogeneous chemistry and photolytic sources of HONO were taken into account. Heterogeneous HONO production mainly accelerated morning ozone formation, albeit slightly. Also HONO formation from excited NO2 only slightly affected HONO and ozone (O3 concentrations. Photo-induced conversion of NO2 into HONO on surfaces covered with organic materials turned out to be a strong source of daytime HONO. Since HONO immediately photo-dissociates during daytime its ambient mixing ratios were only marginally altered (up to 0.5 ppbv, but significant increase in the hydroxyl radical (OH and ozone concentration was obtained. In contrast to heterogeneous HONO formation that mainly accelerated morning ozone formation, inclusion of photo

  13. Pulse radiolysis and cyclic voltammetry studies of redox properties of phenothiazine radicals

    Energy Technology Data Exchange (ETDEWEB)

    Madej, Edyta [Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom)]. E-mail: madej@gci.ac.uk; Wardman, Peter [Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom)

    2006-09-15

    One-electron transfer equilibria between seven phenothiazines were characterized by pulse radiolysis, producing radical-cations via oxidation by Br{sub 2} {sup .-} or (SCN){sub 2} {sup .-} radicals. The reduction potentials of the phenothiazine radicals were determined by cyclic voltammetry. As an independent check, the redox equilibrium between one phenothiazine and the redox indicator ABTS was investigated. The data establish phenothiazines as useful indicators for radical redox properties. However, there are potential problems of aggregation, additional reactions with Br{sup -}/Br{sub 2} {sup .-} and reactivity of the radicals towards buffers or other nucleophiles.

  14. Antioxidant activity of wine pigments derived from anthocyanins: hydrogen transfer reactions to the dpph radical and inhibition of the heme-induced peroxidation of linoleic acid.

    Science.gov (United States)

    Goupy, Pascale; Bautista-Ortin, Ana-Belen; Fulcrand, Helene; Dangles, Olivier

    2009-07-08

    The consumption of red wine can provide substantial concentrations of antioxidant polyphenols, in particular grape anthocyanins (e.g., malvidin-3-O-beta-d-glucoside (1)) and specific red wine pigments formed by reaction between anthocyanins and other wine components such as catechin (3), ethanol, and hydroxycinnamic acids. In this work, the antioxidant properties of red wine pigments (RWPs) are evaluated by the DPPH assay and by inhibition of the heme-induced peroxidation of linoleic acid in acidic conditions (a model of antioxidant action in the gastric compartment). RWPs having a 1 and 3 moieties linked via a CH(3)-CH bridge appear more potent than the pigment with a direct 1-3 linkage. Pyranoanthocyanins derived from 1 reduce more DPPH radicals than 1 irrespective of the substitution of their additional aromatic ring. Pyranoanthocyanins are also efficient inhibitors of the heme-induced lipid peroxidation, although the highly hydrophilic pigment derived from pyruvic acid appears less active.

  15. In vitro alpha glucosidase inhibition and free-radical scavenging activity of propolis from Thai stingless bees in mangosteen orchard

    Directory of Open Access Journals (Sweden)

    Boonyadist Vongsak

    2015-10-01

    Full Text Available ABSTRACTThe chemical component and biological activity of propolis depend on flora area of bee collection and bee species. In the study, the propolis from three stingless bee species, Lepidotrigona ventralis Smith, Lepidotrigona terminata Smith, and Tetragonula pagdeni Schwarz, was collected in the same region of mangosteen garden from Thailand. Total phenolic content, alpha glucosidase inhibitory effect, and free-radical scavenging activity using FRAP, ABTS, DPPH assays were determined. The most potent activity of propolis extract was investigated for bioactive compounds and their quantity. The ethanol extract of T. pagdeni propolis had the highest total phenolic content 12.83 ± 0.72 g of gallic acid equivalents in 100 g of the extract, and the strongest alpha glucosidase inhibitory effect with the IC50 of 70.79 ± 6.44 µg/ml. The free-radical scavenging activity evaluated by FRAP, ABTS, DPPH assays showed the FRAP value of 279.70 ± 20.55 µmol FeSO4 equivalent/g extract and the IC50 of 59.52 ± 10.76 and 122.71 ± 11.76 µg/ml, respectively. Gamma- and alpha-mangostin from T. pagdeni propolis extract were isolated and determined for the biological activity. Gamma-mangostin exhibited the strongest activity for both alpha glucosidase inhibitory effect and free-radical scavenging activity. Using HPLC quantitative analysis method, the content of gamma- and alpha-mangostin in the extract was found to be 0.94 ± 0.01 and 2.77 ± 0.08% (w/w, respectively. These findings suggested that T. pagdeni propolis may be used as a more suitable raw material for nutraceutical and pharmaceutical products and these mangostin derivatives as markers.

  16. Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Ammu

    2010-09-01

    Full Text Available Abstract Background Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals. Methods The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3 cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS. The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls. Results Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL. The extract reduced significantly (p Conclusions The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.

  17. Isoquercitrin Esters with Mono- or Dicarboxylic Acids: Enzymatic Preparation and Properties.

    Science.gov (United States)

    Vavříková, Eva; Langschwager, Fanny; Jezova-Kalachova, Lubica; Křenková, Alena; Mikulová, Barbora; Kuzma, Marek; Křen, Vladimír; Valentová, Kateřina

    2016-06-07

    A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside) esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica), which accepted C₅- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C₂), malonic (C₃), succinic (C₄) and maleic (C₄) acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin-Ciocalteau reagent (FCR) and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) than isoquercitrin; ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies.

  18. Isoquercitrin Esters with Mono- or Dicarboxylic Acids: Enzymatic Preparation and Properties

    Directory of Open Access Journals (Sweden)

    Eva Vavříková

    2016-06-01

    Full Text Available A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica, which accepted C5- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C2, malonic (C3, succinic (C4 and maleic (C4 acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin–Ciocalteau reagent (FCR and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl than isoquercitrin; ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies.

  19. A non-acid-assisted and non-hydroxyl-radical-related catalytic ozonation with ceria supported copper oxide in efficient oxalate degradation in water

    KAUST Repository

    Zhang, Tao

    2012-06-01

    Oxalate is usually used as a refractory model compound that cannot be effectively removed by ozone and hydroxyl radical oxidation in water. In this study, we found that ceria supported CuO significantly improved oxalate degradation in reaction with ozone. The optimum CuO loading amount was 12%. The molar ratio of oxalate removed/ozone consumption reached 0.84. The catalytic ozonation was most effective in a neutral pH range (6.7-7.9) and became ineffective when the water solution was acidic or alkaline. Moreover, bicarbonate, a ubiquitous hydroxyl radical scavenger in natural waters, significantly improved the catalytic degradation of oxalate. Therefore, the degradation relies on neither hydroxyl radical oxidation nor acid assistance, two pathways usually proposed for catalytic ozonation. These special characters of the catalyst make it suitable to be potentially used for practical degradation of refractory hydrophilic organic matter and compounds in water and wastewater. With in situ characterization, the new surface Cu(II) formed from ozone oxidation of the trace Cu(I) of the catalyst was found to be an active site in coordination with oxalate forming multi-dentate surface complex. It is proposed that the complex can be further oxidized by molecular ozone and then decomposes through intra-molecular electron transfer. The ceria support enhanced the activity of the surface Cu(I)/Cu(II) in this process. © 2012 Elsevier B.V.

  20. Intramolecular electron transfer versus substrate oxidation in lactoperoxidase: investigation of radical intermediates by stopped-flow absorption spectrophotometry and (9-285 GHz) electron paramagnetic resonance spectroscopy.

    Science.gov (United States)

    Fielding, Alistair J; Singh, Rahul; Boscolo, Barbara; Loewen, Peter C; Ghibaudi, Elena M; Ivancich, Anabella

    2008-09-16

    We have combined the information obtained from rapid-scan electronic absorption spectrophotometry and multifrequency (9-295 GHz) electron paramagnetic resonance (EPR) spectroscopy to unequivocally determine the electronic nature of the intermediates in milk lactoperoxidase as a function of pH and to monitor their reactivity with organic substrates selected by their different accessibilities to the heme site. The aim was to address the question of the putative catalytic role of the protein-based radicals. This experimental approach allowed us to discriminate between the protein-based radical intermediates and [Fe(IV)=O] species, as well as to directly detect the oxidation products by EPR. The advantageous resolution of the g anisotropy of the Tyr (*) EPR spectrum at high fields showed that the tyrosine of the [Fe(IV)=O Tyr (*)] intermediate has an electropositive and pH-dependent microenvironment [g(x) value of 2.0077(0) at pH >or= 8.0 and 2.0066(2) at 4.0 radical stability and function. Two types of organic molecules (small aromatic vs bulkier substrates) allowed us to distinguish different mechanisms for substrate oxidation. [Fe(IV)=O Por (*+)] is the oxidizing species of benzohydroxamic acid, o-dianisidine, and o-anisidine via a heme-edge reaction and of mitoxantrone via a long-range electron transfer (favored at pH 8) not involving the tyrosyl radical, the formation of which competed with the substrate oxidation at pH 5. In contrast, the very efficient reaction with ABTS at pH 5 is consistent with [Fe(IV)=O Tyr (*)] being the oxidizing species. Accordingly, the identification of the ABTS binding site by X-ray crystallography may be a valuable tool in rational drug design.

  1. Human Pluripotent Stem Cells and Derived Neuroprogenitors Display Differential Degrees of Susceptibility to BH3 Mimetics ABT-263, WEHI-539 and ABT-199.

    Directory of Open Access Journals (Sweden)

    Carolina Paola García

    Full Text Available Human embryonic stem cells (hESCs are hypersensitive to genotoxic stress and display lower survival ability relative to their differentiated progeny. Herein, we attempted to investigate the source of this difference by comparing the DNA damage responses triggered by the topoisomerase I inhibitor camptothecin, in hESCs, human induced pluripotent stem cells (hiPSCs and hESCs-derived neuroprogenitors (NP. We observed that upon camptothecin exposure pluripotent stem cells underwent apoptosis more swiftly and at a higher rate than differentiated cells. However, the cellular response encompassing ataxia-telangiectasia mutated kinase activation and p53 phosphorylation both on serine 15 as well as on serine 46 resulted very similar among the aforementioned cell types. Importantly, we observed that hESCs and hiPSCs express lower levels of the anti-apoptotic protein Bcl-2 than NP. To assess whether Bcl-2 abundance could account for this differential response we treated cells with ABT-263, WEHI-539 and ABT-199, small molecules that preferentially target the BH3-binding pocket of Bcl-xL and/or Bcl-2 and reduce their ability to sequester pro-apoptotic factors. We found that in the absence of stress stimuli, NP exhibited a higher sensitivity to ABT- 263 and WEHI-539 than hESCs and hiPSCs. Conversely, all tested cell types appeared to be highly resistant to the Bcl-2 specific inhibitor, ABT-199. However, in all cases we determined that ABT-263 or WEHI-539 treatment exacerbated camptothecin-induced apoptosis. Importantly, similar responses were observed after siRNA-mediated down-regulation of Bcl-xL or Bcl-2. Taken together, our results suggest that Bcl-xL contrary to Bcl-2 contributes to ensure cell survival and also functions as a primary suppressor of DNA double-strand brake induced apoptosis both in pluripotent and derived NP cells. The emerging knowledge of the relative dependence of pluripotent and progenitor cells on Bcl-2 and Bcl-xL activities may help

  2. Human Pluripotent Stem Cells and Derived Neuroprogenitors Display Differential Degrees of Susceptibility to BH3 Mimetics ABT-263, WEHI-539 and ABT-199

    Science.gov (United States)

    Dimopoulos, Nicolás Alexis; Fernandez Espinosa, Damián Darío; Miriuka, Santiago Gabriel; Sevlever, Gustavo Emilio; Romorini, Leonardo; Scassa, María Elida

    2016-01-01

    Human embryonic stem cells (hESCs) are hypersensitive to genotoxic stress and display lower survival ability relative to their differentiated progeny. Herein, we attempted to investigate the source of this difference by comparing the DNA damage responses triggered by the topoisomerase I inhibitor camptothecin, in hESCs, human induced pluripotent stem cells (hiPSCs) and hESCs-derived neuroprogenitors (NP). We observed that upon camptothecin exposure pluripotent stem cells underwent apoptosis more swiftly and at a higher rate than differentiated cells. However, the cellular response encompassing ataxia-telangiectasia mutated kinase activation and p53 phosphorylation both on serine 15 as well as on serine 46 resulted very similar among the aforementioned cell types. Importantly, we observed that hESCs and hiPSCs express lower levels of the anti-apoptotic protein Bcl-2 than NP. To assess whether Bcl-2 abundance could account for this differential response we treated cells with ABT-263, WEHI-539 and ABT-199, small molecules that preferentially target the BH3-binding pocket of Bcl-xL and/or Bcl-2 and reduce their ability to sequester pro-apoptotic factors. We found that in the absence of stress stimuli, NP exhibited a higher sensitivity to ABT- 263 and WEHI-539 than hESCs and hiPSCs. Conversely, all tested cell types appeared to be highly resistant to the Bcl-2 specific inhibitor, ABT-199. However, in all cases we determined that ABT-263 or WEHI-539 treatment exacerbated camptothecin-induced apoptosis. Importantly, similar responses were observed after siRNA-mediated down-regulation of Bcl-xL or Bcl-2. Taken together, our results suggest that Bcl-xL contrary to Bcl-2 contributes to ensure cell survival and also functions as a primary suppressor of DNA double-strand brake induced apoptosis both in pluripotent and derived NP cells. The emerging knowledge of the relative dependence of pluripotent and progenitor cells on Bcl-2 and Bcl-xL activities may help to predict

  3. Application of Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) Spectroscopy To Determine the Chlorogenic Acid Isomer Profile and Antioxidant Capacity of Coffee Beans.

    Science.gov (United States)

    Liang, Ningjian; Lu, Xiaonan; Hu, Yaxi; Kitts, David D

    2016-01-27

    The chlorogenic acid isomer profile and antioxidant activity of both green and roasted coffee beans are reported herein using ATR-FTIR spectroscopy combined with chemometric analyses. High-performance liquid chromatography (HPLC) quantified different chlorogenic acid isomer contents for reference, whereas ORAC, ABTS, and DPPH were used to determine the antioxidant activity of the same coffee bean extracts. FTIR spectral data and reference data of 42 coffee bean samples were processed to build optimized PLSR models, and 18 samples were used for external validation of constructed PLSR models. In total, six PLSR models were constructed for six chlorogenic acid isomers to predict content, with three PLSR models constructed to forecast the free radical scavenging activities, obtained using different chemical assays. In conclusion, FTIR spectroscopy, coupled with PLSR, serves as a reliable, nondestructive, and rapid analytical method to quantify chlorogenic acids and to assess different free radical-scavenging capacities in coffee beans.

  4. In vitro antioxidant and antibacterial properties of hydrolysed proteins of delimed tannery fleshings: comparison of acid hydrolysis and fermentation methods.

    Science.gov (United States)

    Balakrishnan, Bijinu; Prasad, Binod; Rai, Amit Kumar; Velappan, Suresh Puthanveetil; Subbanna, Mahendrakar Namadev; Narayan, Bhaskar

    2011-04-01

    Proteins in delimed tannery fleshings were fermentatively hydrolysed using Enterococcus faecium NCIM5335 and also hydrolysed using mild organic acids (formic acid and propionic acid). The liquor portion containing hydrolysed proteins was spray dried, in both the cases, to obtain a powder. The spray dried powder was evaluated for in vitro antioxidant activities with respect to scavenging different free radicals and antibacterial properties against nine different pathogens. Fermentation and acid hydrolysates scavenged 83 and 75.3% of 2,2-azino-bis-3-ethyl-benzthiazoline-6-sulphonic acid (ABTS) radicals, respectively, at a protein concentration of 0.25 mg. Further, fermentation hydrolysate showed higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of 59% as compared to 56% scavenging by acid hydrolysate at a protein concentration of 5 mg. Acid hydrolysate exhibited lesser (82.3%) peroxy radical scavenging compared to hydrolysate from fermentation (88.2%) at a protein concentration of 10 mg. However, acid hydrolysate exhibited higher (89.2%) superoxide anion scavenging while its fermentation counterpart showed lower activity (85.4%) at 2.5 mg hydrolysate protein. Well as superoxide anion scavenging properties. All the in vitro antioxidant properties exhibited dose dependency. Fermentation hydrolysate exhibited maximum antagonistic activity against Salmonella typhi FB231, from among host of pathogens evaluated. Both the hydrolysates have potential to be ingredients in animal feeds and can help reduce oxidative stress in the animals.

  5. Effect of metal ions on the reactions of the cumyloxyl radical with hydrogen atom donors. Fine control on hydrogen abstraction reactivity determined by Lewis acid-base interactions.

    Science.gov (United States)

    Salamone, Michela; Mangiacapra, Livia; DiLabio, Gino A; Bietti, Massimo

    2013-01-09

    A time-resolved kinetic study on the effect of metal ions (M(n+)) on hydrogen abstraction reactions from C-H donor substrates by the cumyloxyl radical (CumO(•)) was carried out in acetonitrile. Metal salt addition was observed to increase the CumO(•) β-scission rate constant in the order Li(+) > Mg(2+) > Na(+). These effects were explained in terms of the stabilization of the β-scission transition state determined by Lewis acid-base interactions between M(n+) and the radical. When hydrogen abstraction from 1,4-cyclohexadiene was studied in the presence of LiClO(4) and Mg(ClO(4))(2), a slight increase in rate constant (k(H)) was observed indicating that interaction between M(n+) and CumO(•) can also influence, although to a limited extent, the hydrogen abstraction reactivity of alkoxyl radicals. With Lewis basic C-H donors such as THF and tertiary amines, a decrease in k(H) with increasing Lewis acidity of M(n+) was observed (k(H)(MeCN) > k(H)(Li(+)) > k(H)(Mg(2+))). This behavior was explained in terms of the stronger Lewis acid-base interaction of M(n+) with the substrate as compared to the radical. This interaction reduces the degree of overlap between the α-C-H σ* orbital and a heteroatom lone-pair, increasing the C-H BDE and destabilizing the carbon centered radical formed after abstraction. With tertiary amines, a >2-order of magnitude decrease in k(H) was measured after Mg(ClO(4))(2) addition up to a 1.5:1 amine/Mg(ClO(4))(2) ratio. At higher amine concentrations, very similar k(H) values were measured with and without Mg(ClO(4))(2). These results clearly show that with strong Lewis basic substrates variations in the nature and concentration of M(n+) can dramatically influence k(H), allowing for a fine control of the substrate hydrogen atom donor ability, thus providing a convenient method for C-H deactivation. The implications and generality of these findings are discussed.

  6. 78 FR 29367 - Access to Confidential Business Information by ABT Associates, Incorporated; Perry Johnson...

    Science.gov (United States)

    2013-05-20

    .../operation agreements, amounts and types of e-waste processed; and environmental health and safety plans; and... certification programs in the U.S.: The Responsible Recycling Practices (R2) and e-Stewards Standard for Responsible Recycling and Reuse of Electronic Equipment (e-Stewards). Contractor support from ABT will...

  7. 40 CFR 1054.730 - What ABT reports must I send to EPA?

    Science.gov (United States)

    2010-07-01

    ... POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, SMALL NONROAD SPARK-IGNITION ENGINES AND EQUIPMENT Averaging, Banking, and Trading for Certification § 1054.730 What ABT reports must I send to EPA? (a) If any...-data engine or the appropriate internal surface area of the fuel tank. (6) Useful life. (7)...

  8. ABCB1, ABCG2, and PTEN determine the response of glioblastoma to temozolomide and ABT-888 therapy

    NARCIS (Netherlands)

    Lin, Fan; de Gooijer, Mark C; Roig, Eloy Moreno; Buil, Levi C M; Christner, Susan M; Beumer, Jan H; Würdinger, Thomas; Beijnen, Jos H; van Tellingen, Olaf

    2014-01-01

    PURPOSE: Little is known about the optimal clinical use of ABT-888 (veliparib) for treatment of glioblastoma. ABT-888 is a PARP inhibitor undergoing extensive clinical evaluation in glioblastoma, because it may synergize with the standard-of-care temozolomide (TMZ). We have elucidated important fact

  9. In Vitro Antioxidant Activities, Free Radical Scavenging Capacity, and Tyrosinase Inhibitory of Flavonoid Compounds and Ferulic Acid from Spiranthes sinensis (Pers. Ames

    Directory of Open Access Journals (Sweden)

    Chung Pin Liang

    2014-04-01

    Full Text Available In this study, ultrasound-assisted extraction (UAE and other methods of extracting flavonoid compounds and ferulic acid (FA from S. sinensis were investigated. Five different extraction methods, including water extraction (W, water extraction using UAE (W+U, 75% ethanol extraction (E, 75% ethanol extraction using UAE (E+U, and supercritical CO2 extraction (SFE were applied in the extraction of bioactive compounds (flavonoids and ferulic acid in order to compare their efficiency. The highest yield of flavonoids (4.28 mg/g and ferulic acid (4.13 mg/g content was detected in the E+U extract. Furthermore, S. sinensis extracts obtained by E+U show high antioxidant activity, and IC50 values of 0.47 mg/mL for DPPH radicals and 0.205 mg/mL for metal chelating activity. The total antioxidant assay shows superoxide radical scavenging capacity and in vitro mushroom tyrosinase inhibition in a dose-dependent manner, suggesting that E+U can be used for extraction of bioactive compounds from S. sinensis.

  10. In vitro antioxidant activities, free radical scavenging capacity, and tyrosinase inhibitory of flavonoid compounds and ferulic acid from Spiranthes sinensis (Pers.) Ames.

    Science.gov (United States)

    Liang, Chung Pin; Chang, Chia Hao; Liang, Chien Cheng; Hung, Kuei Yu; Hsieh, Chang Wei

    2014-04-15

    In this study, ultrasound-assisted extraction (UAE) and other methods of extracting flavonoid compounds and ferulic acid (FA) from S. sinensis were investigated. Five different extraction methods, including water extraction (W), water extraction using UAE (W+U), 75% ethanol extraction (E), 75% ethanol extraction using UAE (E+U), and supercritical CO2 extraction (SFE) were applied in the extraction of bioactive compounds (flavonoids and ferulic acid) in order to compare their efficiency. The highest yield of flavonoids (4.28 mg/g) and ferulic acid (4.13 mg/g) content was detected in the E+U extract. Furthermore, S. sinensis extracts obtained by E+U show high antioxidant activity, and IC50 values of 0.47 mg/mL for DPPH radicals and 0.205 mg/mL for metal chelating activity. The total antioxidant assay shows superoxide radical scavenging capacity and in vitro mushroom tyrosinase inhibition in a dose-dependent manner, suggesting that E+U can be used for extraction of bioactive compounds from S. sinensis.

  11. A novel detection approach based on chromophore-decolorizing with free radical and application to photometric determination of copper with acid chrome dark blue.

    Science.gov (United States)

    Gao, Hong-Wen; Chen, Fang-Fang; Chen, Ling; Zeng, Teng; Pan, Lu-Ting; Li, Jian-Hua; Luo, Hua-Fei

    2007-03-21

    A novel detection approach named chromophore-decolorizing with free radicals is developed for determination of trace heavy metal. The hydroxyl radicals (HO) generated from Fe(III) and hydrogen peroxide will oxidize the free chromophore into almost colorless products. The copper-acid chrome dark blue (ACDB) complexation was investigated at pH 5.07. In the presence of Fe(III) and hydrogen peroxide, the excess ACDB was decolorized in the Cu-ACDB reaction solution, and the final solution contained only one color compound, the Cu-ACDB complex. After oxidation of free hydroxyl radicals, the complexation becomes sensitive and selective and it has been used for the quantitation of trace amounts of Cu(II) dissolved in natural water. Beer's law is obeyed in the range from 0 to 0.500 microg mL(-1) Cu(II) and the limit of detection is only 6 microg L(-1) Cu(II). Besides, the Cu-ACDB complex formed was characterized.

  12. A ¹H NMR Investigation of the Interaction between Phenolic Acids Found in Mango (Manguifera indica cv Ataulfo and Papaya (Carica papaya cv Maradol and 1,1-diphenyl-2-picrylhydrazyl (DPPH Free Radicals.

    Directory of Open Access Journals (Sweden)

    Luis M López-Martínez

    Full Text Available The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this paper, we used 1H NMR to analyze the interactions and mechanisms that are present in major phenolic acids found in mango (gallic, protocatechuic, chlorogenic and vanillic acids and papaya (caffeic, ferulic and p-coumaric acids, and the DPPH radical was used to evaluate the effect of the antioxidant mixtures. The interactions were found to occur via hydrogen bonds between the -OH and -COOH groups. Moreover, the phenolic acids exhibit two types of mechanisms for the neutralization of the DPPH radical. According to the results, these two mechanisms are Hydrogen Atom Transfer (HAT and Single Electron Transfer (SET. The ability of the phenolic acid to neutralize the DPPH radical decreases in the following order in mango: gallic > chlorogenic > protocatechuic > vanillic. Moreover, within the acids found in papaya, the order was as follows: caffeic > p-coumaric > ferulic.

  13. A ¹H NMR Investigation of the Interaction between Phenolic Acids Found in Mango (Manguifera indica cv Ataulfo) and Papaya (Carica papaya cv Maradol) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) Free Radicals.

    Science.gov (United States)

    López-Martínez, Luis M; Santacruz-Ortega, Hisila; Navarro, Rosa-Elena; Sotelo-Mundo, Rogerio R; González-Aguilar, Gustavo A

    2015-01-01

    The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this paper, we used 1H NMR to analyze the interactions and mechanisms that are present in major phenolic acids found in mango (gallic, protocatechuic, chlorogenic and vanillic acids) and papaya (caffeic, ferulic and p-coumaric acids), and the DPPH radical was used to evaluate the effect of the antioxidant mixtures. The interactions were found to occur via hydrogen bonds between the -OH and -COOH groups. Moreover, the phenolic acids exhibit two types of mechanisms for the neutralization of the DPPH radical. According to the results, these two mechanisms are Hydrogen Atom Transfer (HAT) and Single Electron Transfer (SET). The ability of the phenolic acid to neutralize the DPPH radical decreases in the following order in mango: gallic > chlorogenic > protocatechuic > vanillic. Moreover, within the acids found in papaya, the order was as follows: caffeic > p-coumaric > ferulic.

  14. A 1H NMR Investigation of the Interaction between Phenolic Acids Found in Mango (Manguifera indica cv Ataulfo) and Papaya (Carica papaya cv Maradol) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) Free Radicals

    Science.gov (United States)

    López-Martínez, Luis M.; Santacruz-Ortega, Hisila; Navarro, Rosa-Elena; Sotelo-Mundo, Rogerio R.; González-Aguilar, Gustavo A.

    2015-01-01

    The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this paper, we used 1H NMR to analyze the interactions and mechanisms that are present in major phenolic acids found in mango (gallic, protocatechuic, chlorogenic and vanillic acids) and papaya (caffeic, ferulic and p-coumaric acids), and the DPPH radical was used to evaluate the effect of the antioxidant mixtures. The interactions were found to occur via hydrogen bonds between the -OH and -COOH groups. Moreover, the phenolic acids exhibit two types of mechanisms for the neutralization of the DPPH radical. According to the results, these two mechanisms are Hydrogen Atom Transfer (HAT) and Single Electron Transfer (SET). The ability of the phenolic acid to neutralize the DPPH radical decreases in the following order in mango: gallic > chlorogenic > protocatechuic > vanillic. Moreover, within the acids found in papaya, the order was as follows: caffeic > p-coumaric > ferulic. PMID:26559189

  15. Oil, protein, antioxidants and free radical scavenging activity of stone from wild olive trees (Olea europaea L.).

    Science.gov (United States)

    Hannachi, Hédia; Elfalleh, Walid; Marzouk, Sizaiem

    2013-05-01

    The wild olive trees or oleaster (var. sylvestris) and the cultivated olive trees (var. europaea) constitute the two botanical varieties of Olea europaea L. from Mediterranean. In this study, a partial chemical profile was conducted including the total lipids, the fatty acid profiles, soluble proteins, polyphenols, flavanoids contents and antioxidants activities of stone from six oleaster trees. The comparison was made by two olive cultivars cultivated in the same region. The oleaster and cultivar stones were richer in oil content having an average of 8.99 and 7.38 % dry weight basis (DW), respectively. Qualitatively, all studied oils have the same fatty acids profile with the oleic acid C18:1n-9 as the major fatty acid. The oleaster stone oils were richer in monounsaturated fatty acids having an average of 64.87%. They, also, richer in protein content with an average of 198.86 mg/g DW.The globulin is the major fraction, followed by the albumin, the prolamin and the glutemin fractions. The oleaster stone extracts contain polyphenols, flavonoids with an average of 151.14 and 11.91 mg gallic acid equivalent/100g of DW, respectively. The studied extracts showed antioxidant activity using the free radical scavenging activity determined by DPPH and ABTS. The unexploited oleaster stone seems to be a source of oil with good fatty acids balance, in protein and antioxidants metabolites and would be useful for the formulation of supplements and/or pharmaceutical ingredients.

  16. Effect of base stacking on the acid-base properties of the adenine cation radical [A*+] in solution: ESR and DFT studies.

    Science.gov (United States)

    Adhikary, Amitava; Kumar, Anil; Khanduri, Deepti; Sevilla, Michael D

    2008-08-06

    In this study, the acid-base properties of the adenine cation radical are investigated by means of experiment and theory. Adenine cation radical (A*(+)) is produced by one-electron oxidation of dAdo and of the stacked DNA-oligomer (dA)6 by Cl2*(-) in aqueous glass (7.5 M LiCl in H2O and in D2O) and investigated by ESR spectroscopy. Theoretical calculations and deuterium substitution at C8-H and N6-H in dAdo aid in our assignments of structure. We find the pKa value of A*(+) in this system to be ca. 8 at 150 K in seeming contradiction to the accepted value of or = 160 K, complete deprotonation of A*(+) occurs in dAdo in these glassy systems even at pH ca. 3. A*(+) found in (dA)6 at 150 K also deprotonates on thermal annealing. The stability of A*(+) at 150 K in these systems is attributed to charge delocalization between stacked bases. Theoretical calculations at various levels (DFT B3LYP/6-31G*, MPWB95, and HF-MP2) predict binding energies for the adenine stacked dimer cation radical of 12 to 16 kcal/mol. Further DFT B3LYP/6-31G* calculations predict that, in aqueous solution, monomeric A*(+) should deprotonate spontaneously (a predicted pKa of ca. -0.3 for A*(+)). However, the charge resonance stabilized dimer AA*(+) is predicted to result in a significant barrier to deprotonation and a calculated pKa of ca. 7 for the AA*(+) dimer which is 7 pH units higher than the monomer. These theoretical and experimental results suggest that A*(+) isolated in solution and A*(+) in adenine stacks have highly differing acid-base properties resulting from the stabilization induced by hole delocalization within adenine stacks.

  17. Melatonin scavenges phenylglyoxylic ketyl radicals.

    Science.gov (United States)

    Sersen, F; Vencel, T; Annus, J

    2004-12-01

    The antioxidant properties of melatonin were tested in this work by EPR technique. It was found that melatonin scavenges phenylglyoxylic ketyl radicals. Its effectiveness was 10-times lower than that of vitamin C. A new method of generation of phenylglyoxylic ketyl radicals by spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propan-2-ol was used.

  18. Increased lymphocyte apoptosis in mouse models of colitis upon ABT-737 treatment is dependent upon BIM expression.

    Science.gov (United States)

    Lutz, C; Mozaffari, M; Tosevski, V; Caj, M; Cippà, P; McRae, B L; Graff, C L; Rogler, G; Fried, M; Hausmann, M

    2015-08-01

    Exaggerated activation of lymphocytes contributes to the pathogenesis of inflammatory bowel disease (IBD). Medical therapies are linked to the BCL-2 family-mediated apoptosis. Imbalance in BCL-2 family proteins may cause failure in therapeutic responses. We investigated the role of BCL-2 inhibitor ABT-737 for lymphocyte apoptosis in mice under inflammatory conditions. B.6129P2-interleukin (IL)-10(tm1Cgn) /J (IL-10(-/-) ) weighing 25-30 g with ongoing colitis were used. Fifty mg/kg/day ABT-737 was injected intraperitoneally (i.p.). Haematological analyses were performed with an ADVIA 2120 flow cytometer and mass cytometry with a CyTOF 2. Following i.p. administration, ABT-737 was detected in both spontaneous and acute colitis in peripheral blood (PBL) and colon tissue. Treatment led to lymphopenia. CD4(+) CD44(+) CD62L(+) central memory and CD8(+) , CD44(+) CD62L(-) central memory T cells were decreased in PBL upon ABT-737 compared to vehicle-receiving controls. Increased apoptosis upon ABT-737 was determined in blood lymphocytes, splenocytes and Peyer's patches and was accompanied by a decrease in TNF and IL-1B. ABT-737 positively altered the colonic mucosa and ameliorated inflammation, as shown by colonoscopy, histology and colon length. A decreased BIM/BCL-2 ratio or absence of BIM in both Bim(-) (/) (-) and Il10(-) (/) (-) × Bim(-) (/) (-) impeded the protective effect of ABT-737. The BIM/BCL-2 ratio decreased with age and during the course of treatment. Thus, long-term treatment resulted in adapted TNF levels and macroscopic mucosal damage. ABT-737 was efficacious in diminishing lymphocytes and ameliorating colitis in a BIM-dependent manner. Regulation of inappropriate survival of lymphocytes by ABT-737 may provide a therapeutic strategy in IBD.

  19. Enzyme inhibitory and radical scavenging effects of some antidiabetic plants of Turkey

    Directory of Open Access Journals (Sweden)

    Nilüfer Orhan

    2014-06-01

    Full Text Available Objective(s:Ethnopharmacological field surveys demonstrated that many plants, such as Gentiana olivieri, Helichrysum graveolens, Helichrysum plicatum ssp. plicatum, Juniperus oxycedrus ssp. oxycedrus, Juniperus  communis var. saxatilis, Viscum album (ssp. album, ssp. austriacum, are used as traditional medicine for diabetes in different regions of Anatolia. The present study was designed to evaluate the in vitro antidiabetic effects of some selected plants, tested in animal models recently. Materials and Methods: α-glucosidase and α-amylase enzyme inhibitory effects of the plant extracts were investigated and Acarbose was used as a reference drug. Additionally, radical scavenging capacities were determined using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid ABTS radical cation scavenging assay and total phenolic content of the extracts were evaluated using Folin Ciocalteu method. Results: H. graveolens ethanol extract exhibited the highest inhibitory activity (55.7 % ± 2.2 on α-amylase enzyme. Additionally, J. oxycedrus hydro-alcoholic leaf extract had potent α-amylase inhibitory effect, while the hydro-alcoholic extract of J. communis fruit showed the highest α-glucosidase inhibitory activity (IC50: 4.4 μg/ml. Conclusion:Results indicated that, antidiabetic effect of hydro-alcoholic extracts of H. graveolens capitulums, J. communis fruit and J. oxycedrus leaf might arise from inhibition of digestive enzymes.

  20. Differentiation between stoichiometric and anticatalytic antioxidant properties of benzoic acid analogues: a structure/redox potential relationship study.

    Science.gov (United States)

    Franck, Thierry; Mouithys-Mickalad, Ange; Robert, Thierry; Ghitti, Gianangelo; Deby-Dupont, Ginette; Neven, Philippe; Serteyn, Didier

    2013-11-25

    We investigated the antioxidant activities of some phenolic acid derivatives on a cell free system and on cellular and enzymatic models involved in inflammation. The stoichiometric antioxidant activities of phenolic acid derivatives were studied by measuring their capacity to scavenge the radical cation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS(+)) and reactive oxygen species (ROS) produced by stimulated neutrophils. The anticatalytic antioxidant capacity of the molecules was evaluated on the activity of myeloperoxidase (MPO), an oxidant enzyme present in and released by the primary granules of neutrophils. The ROS produced by PMA-stimulated neutrophils were measured by lucigenin-enhanced chemiluminescence (CL) and the potential interaction of the molecules with MPO was investigated without interferences due to medium by Specific Immuno-Extraction Followed by Enzyme Detection (SIEFED). The antioxidant activities of the phenolic compounds were correlated to their redox potentials measured by differential pulse voltammetry (DPV), and discussed in relation to their molecular structure. The ability of the phenolic molecules to scavenge ABTS radicals and ROS derived from neutrophils was inversely correlated to their increased redox potential. The number of hydroxyl groups (three) and their position (catechol) were essential for their efficacy as stoichiometric antioxidants or scavengers. On MPO activity, the inhibitory capacity of the molecules was not really correlated with their redox potential. Likewise, for the inhibition of MPO activity the number of OH groups and mainly the elongation of the carboxylic group were essential, probably by facilitating the interaction with the active site or the structure of the enzyme. The redox potential measurement, combined with ABTS and CL techniques, seems to be a good technique to select stoichiometric antioxidants but not anticatalytic ones, as seen for MPO, what rather involves a direct interaction with

  1. ABT737 enhances cholangiocarcinoma sensitivity to cisplatin through regulation of mitochondrial dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhongqi [Department of Hepatobiliary & Pancreas Surgery, The First Hospital, Jilin University, Changchun, Jilin 130021 (China); Yu, Huimei [Department of Pathophysiology, School of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021 (China); Cui, Ni [Bethune Medical College, Jilin University, Changchun, Jilin 130021 (China); Kong, Xianggui; Liu, Xiaomin; Chang, Yulei [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033 (China); Wu, Yao [Department of Pathophysiology, School of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021 (China); Sun, Liankun, E-mail: sunlk@jlu.edu.cn [Department of Pathophysiology, School of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021 (China); Wang, Guangyi, E-mail: wgymd@sina.com [Department of Hepatobiliary & Pancreas Surgery, The First Hospital, Jilin University, Changchun, Jilin 130021 (China)

    2015-07-01

    Cholangiocarcinoma responses weakly to cisplatin. Mitochondrial dynamics participate in the response to various stresses, and mainly involve mitophagy and mitochondrial fusion and fission. Bcl-2 family proteins play critical roles in orchestrating mitochondrial dynamics, and are involved in the resistance to cisplatin. Here we reported that ABT737, combined with cisplatin, can promote cholangiocarcinoma cells to undergo apoptosis. We found that the combined treatment decreased the Mcl-1 pro-survival form and increased Bak. Cells undergoing cisplatin treatment showed hyperfused mitochondria, whereas fragmentation was dominant in the mitochondria of cells exposed to the combined treatment, with higher Fis1 levels, decreased Mfn2 and OPA1 levels, increased ratio of Drp1 60 kD to 80 kD form, and more Drp1 located on mitochondria. More p62 aggregates were observed in cells with fragmented mitochondria, and they gradually translocated to mitochondria. Mitophagy was induced by the combined treatment. Knockdown p62 decreased the Drp1 ratio, increased Tom20, and increased cell viability. Our data indicated that mitochondrial dynamics play an important role in the response of cholangiocarcinoma to cisplatin. ABT737 might enhance cholangiocarcinoma sensitivity to cisplatin through regulation of mitochondrial dynamics and the balance within Bcl-2 family proteins. Furthermore, p62 seems to be critical in the regulation of mitochondrial dynamics. - Highlights: • Cholangiocarcinoma may adapt to cisplatin through mitochondrial fusion. • ABT737 sensitizes cholangiocarcinoma to cisplatin by promoting fission and mitophagy. • p62 might participate in the regulation of mitochondrial fission and mitophagy.

  2. Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies

    Directory of Open Access Journals (Sweden)

    Katty Wan

    2010-05-01

    Full Text Available A fully automated 96-well On-Line Solid Phase Extraction (SPE followed by High Performance Liquid Chromatography (HPLC-Tandem Mass Spectrometric (MS/MS method for the determination of ABT-925 (2-{3-[4-(2-tert-Butyl-6-trifluoromethyl-pyrimidin-4-yl-piperazin-1-yl-propyl-sulfanyl}-3H-pyrimidin-4-one fumarate in human plasma was developed, validated and utilized in Phase II clinical studies. 50 µL of plasma sample was fortified with internal standard (IS, d8-ABT-925 and extracted on-line with Cohesive Turbo Flow Cyclone P HTLC column. The chromatographic separation was performed on Aquasil C18 (3 μm 50 × 3 mm HPLC column with a mobile phase consisting of 50/50/0.1 (v/v/v ACN/H2O/formic acid. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM of m/z 457.4 → 329.4 for analyte and m/z 465.5 → 337.5 for IS.The peak area ratio (analyte/IS was used to quantitate ABT-925. A dynamic range of 0.0102 μg/mL to 5.24 μg/mL was established after the validation. The validated method was then used for two Phase II studies. To demonstrate the method reproducibility, approximately 10% of the incurred samples from one study were repeated in singlet. The repeated values were compared to the initial values. All repeated values agreed within ±15% of the mean values.

  3. Quantitative Determination of ABT-925 in Human Plasma by On-Line SPE and LC-MS/MS: Validation and Sample Analysis in Phase II Studies.

    Science.gov (United States)

    Wan, Katty; Rieser, Matthew; El-Shourbagy, Tawakol

    2010-05-04

    A fully automated 96-well On-Line Solid Phase Extraction (SPE) followed by High Performance Liquid Chromatography (HPLC)-Tandem Mass Spectrometric (MS/MS) method for the determination of ABT-925 (2-{3-[4-(2-tert-Butyl-6-trifluoromethyl-pyrimidin-4-yl)-piperazin-1-yl)-propyl-sulfanyl}-3H-pyrimidin-4-one fumarate) in human plasma was developed, validated and utilized in Phase II clinical studies. 50 µL of plasma sample was fortified with internal standard (IS, d8-ABT-925) and extracted on-line with Cohesive Turbo Flow Cyclone P HTLC column. The chromatographic separation was performed on Aquasil C18 (3 μm 50 × 3 mm) HPLC column with a mobile phase consisting of 50/50/0.1 (v/v/v) ACN/H₂O/formic acid. The mass spectrometric measurement was conducted under positive ion mode using multiple reaction monitoring (MRM) of m/z 457.4 → 329.4 for analyte and m/z 465.5 → 337.5 for IS.The peak area ratio (analyte/IS) was used to quantitate ABT-925. A dynamic range of 0.0102 μg/mL to 5.24 μg/mL was established after the validation. The validated method was then used for two Phase II studies. To demonstrate the method reproducibility, approximately 10% of the incurred samples from one study were repeated in singlet. The repeated values were compared to the initial values. All repeated values agreed within ±15% of the mean values.

  4. THERMOCHEMISTRY OF HYDROCARBON RADICALS

    Energy Technology Data Exchange (ETDEWEB)

    Kent M. Ervin, Principal Investigator

    2004-08-17

    Gas phase negative ion chemistry methods are employed to determine enthalpies of formation of hydrocarbon radicals that are important in combustion processes and to investigate the dynamics of ion-molecule reactions. Using guided ion beam tandem mass spectrometry, we measure collisional threshold energies of endoergic proton transfer and hydrogen atom transfer reactions of hydrocarbon molecules with negative reagent ions. The measured reaction threshold energies for proton transfer yield the relative gas phase acidities. In an alternative methodology, competitive collision-induced dissociation of proton-bound ion-molecule complexes provides accurate gas phase acidities relative to a reference acid. Combined with the electron affinity of the R {center_dot} radical, the gas phase acidity yields the RH bond dissociation energy of the corresponding neutral molecule, or equivalently the enthalpy of formation of the R{center_dot} organic radical, using equation: D(R-H) = {Delta}{sub acid}H(RH) + EA(R) - IE(H). The threshold energy for hydrogen abstraction from a hydrocarbon molecule yields its hydrogen atom affinity relative to the reagent anion, providing the RH bond dissociation energy directly. Electronic structure calculations are used to evaluate the possibility of potential energy barriers or dynamical constrictions along the reaction path, and as input for RRKM and phase space theory calculations. In newer experiments, we have measured the product velocity distributions to obtain additional information on the energetics and dynamics of the reactions.

  5. Caracterização físico-química de polpas de frutos da Amazônia e sua correlação com a atividade anti-radical livre Physical and chemical characterization of fruit pulps from Amazonia and their correlation to free radical scavenger activity

    Directory of Open Access Journals (Sweden)

    Gisele André Baptista Canuto

    2010-12-01

    Full Text Available Características físico-químicas (cor, pH, acidez total titulável, sólidos solúveis totais, conteúdo de lipídios e umidade e níveis de compostos bioativos (ácido ascórbico, fenólicos totais foram determinados em quinze amostras de polpas de frutos procedentes da região Amazônica (abiu, acerola, açaí, araçá-boi, bacaba, bacuri, buriti, cajá, cajarana, caju, cupuaçu, graviola, murici, noni e tamarindo. A atividade de radicais livres foi avaliada pelo método de ABTS. Algumas polpas apresentaram alta potencialidade antioxidante, associada com a atividade antirradicais livres obtida e os conteúdos dos componentes bioativos como compostos fenólicos e ácido ascórbico, destacando-se acerola e acaí. O conteúdo total de compostos fenólicos foi correlacionado à capacidade antioxidante das polpas.Physical and chemical characteristics (color, pH, titratable acidity, total soluble solids, lipid content, moisture and levels of bioactive compounds (ascorbic acid, total phenolics were determined in fifteen samples of fruit pulps from Amazonia (abiu, acerola, açaí, araça-boi, bacaba, bacuri, buriti, cajá, cajarana, caju, cupuaçu, graviola, murici, noni e tamarindo. The free radical scavenger activity was evaluated by the ABTS assay. Some pulps presented high antioxidant potential, associated with the free radical scavenger activity measured and the content of bioactive components, such as phenolic compounds and ascorbic acid, especialy in acerola and açaí. The total phenolic content was correlated to antioxidant capacity of pulps.

  6. Impact of nitrous acid photolysis on the total hydroxyl radical budget during the Limitation of Oxidant Production/Pianura Padana Produzione di Ozono study in Milan

    Science.gov (United States)

    Alicke, B.; Platt, U.; Stutz, J.

    2002-11-01

    The photolysis of nitrous acid (HONO) in the early morning hours is believed to be a significant source of hydroxyl radicals (OH), the most important daytime oxidizing species. Although the importance of this mechanism has been recognized for many years, no accurate experimental quantification is available. Here we present measurements of HONO, NO2, SO2, O3 and HCHO by Differential Optical Absorption Spectroscopy (DOAS) during the Limitation of Oxidant Production/Pianura Padana Produzione di Ozono (LOOP/PIPAPO) study in May-June 1998 in Milan, Italy. The concentration of NO and J(NO2)/J(HONO) were simultaneously monitored by in situ monitors. The photolysis frequencies of HCHO and O3 were determined with a radiative transfer model. High nocturnal HONO mixing ratios of up to 4.4 ppb were regularly observed. Elevated daytime HONO levels during cloudy periods show that the formation of HONO proceeds after sunrise and therefore also represents a source of hydroxyl radicals throughout the day. Averaged over 24 hours, HCHO photolysis is the most important source of OH in Milan, followed by either ozone or HONO photolysis. Our observations indicate that on certain days the OH production from HONO can be even more important than that from ozone photolysis. The diurnal variation of the different OH formation mechanisms shows that HONO photolysis is by far the most important source in the early hours of the morning, and can be as large as and even surpass the total OH production at noon.

  7. Reaction of sulphate radical anion (SO{sub 4}{sup {center_dot}}{sup -}) with cyanuric acid. A potential reaction for its degradation?

    Energy Technology Data Exchange (ETDEWEB)

    Manoj, P.; Varghese, R.; Manoj, V.M.; Aravindakumar, C.T. [Mahatma Gandhi University, School of Chemical Sciences, Kottayam (India)

    2002-01-01

    A novel reaction between sulfate radical anion (SO{sub 4}{sup {center_dot}}{sup -}) and cyanuric acid (CA), a non-degradable end product of the oxidative degradation of the triazine based herbicide, atrazine, is presented using laser flash photolysis and steady state radiolysis techniques at pH 5. A second order rate constant of 1.9x10{sup 7} dm{sup 3} mol{sup -1} s{sup -1} has been determined and the transient intermediate ({lambda}{sub max}=330 nm) is assigned to a radical cation of CA (CA{sup {center_dot}}{sup +}). The degradation profile indicated that about 76% of CA have been decomposed after an absorbed {gamma}-radiation dose of 18 kGy. It is therefore proposed that the reaction of SO{sub 4}{sup {center_dot}}{sup -} could be utilised for the degradation of CA in aqueous medium which is normally stable to any Advanced Oxidation Processes. (author)

  8. Nitrogen Oxides in the Nocturnal Boundary Layer: Chemistry of Nitrous Acid (HONO) and the Nitrate Radical (N03)

    Energy Technology Data Exchange (ETDEWEB)

    Jochen Stutz

    2005-05-24

    Summary Chemical processes occurring at night in the lowest part of the urban atmosphere, the so called nocturnal boundary layer (NBL), can influence the composition of the atmosphere during the night as well as the following day. They may impact the budgets of some of the most important pollutants, such as ozone and nitrogen oxides, as well as influence size and composition of particular matter. Few studies have thus far concentrated on the nocturnal chemistry of the urban NBL, most likely due to the strong influence of vertical transport and mixing, which requires the measurement of trace gas profiles instead of simple point observations. Motivated by our lack of observations and understanding of nocturnal chemistry, the focus of this project was the study of the vertical distribution of trace gases and the altitude dependence of nocturnal chemistry under polluted conditions through field observations and modeling studies. The analysis of three field experiments (TEXAQS, Houston, 2000; Phoenix Sunrise Ozone Experiment, 2001; NAPOX, Boston, 2002), two of which were performed in this project, showed that ozone concentrations typically increase with height in the lowest 150m, while NO2 typically decreases. NO3, the dominant nocturnal radical species, showed much higher concentrations in the upper part of the NBL, and was often not present at the ground. With the help of a one-dimensional chemical transport model, developed in this project, we found that the interaction of ground emissions of NOx and hydrocarbons, together with their vertical transport, is responsible for the vertical profiles. The dominant chemical reactions influencing ozone, NO2 and NO3 are the reaction of ozone and NO3 with freshly emitted NO. Sensitivity studies with our model showed that the magnitude of the trace gas gradients depend both on the emission rates and the vertical stability of the NBL. Observations and model analysis clearly show that nocturnal chemistry in urban areas is altitude

  9. ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia.

    Science.gov (United States)

    Shankar, Deepa B; Li, Junling; Tapang, Paul; Owen McCall, J; Pease, Lori J; Dai, Yujia; Wei, Ru-Qi; Albert, Daniel H; Bouska, Jennifer J; Osterling, Donald J; Guo, Jun; Marcotte, Patrick A; Johnson, Eric F; Soni, Niru; Hartandi, Kresna; Michaelides, Michael R; Davidsen, Steven K; Priceman, Saul J; Chang, Jenny C; Rhodes, Katrin; Shah, Neil; Moore, Theodore B; Sakamoto, Kathleen M; Glaser, Keith B

    2007-04-15

    In 15% to 30% of patients with acute myeloid leukemia (AML), aberrant proliferation is a consequence of a juxtamembrane mutation in the FLT3 gene (FMS-like tyrosine kinase 3-internal tandem duplication [FLT3-ITD]), causing constitutive kinase activity. ABT-869 (a multitargeted receptor tyrosine kinase inhibitor) inhibited the phosphorylation of FLT3, STAT5, and ERK, as well as Pim-1 expression in MV-4-11 and MOLM-13 cells (IC(50) approximately 1-10 nM) harboring the FLT3-ITD. ABT-869 inhibited the proliferation of these cells (IC(50) = 4 and 6 nM, respectively) through the induction of apoptosis (increased sub-G(0)/G(1) phase, caspase activation, and PARP cleavage), whereas cells harboring wild-type (wt)-FLT3 were less sensitive. In normal human blood spiked with AML cells, ABT-869 inhibited phosphorylation of FLT3 (IC(50) approximately 100 nM), STAT5, and ERK, and decreased Pim-1 expression. In methylcellulose-based colony-forming assays, ABT-869 had no significant effect up to 1000 nM on normal hematopoietic progenitor cells, whereas in AML patient samples harboring both FLT3-ITD and wt-FLT3, ABT-869 inhibited colony formation (IC(50) = 100 and 1000 nM, respectively). ABT-869 dose-dependently inhibited MV-4-11 and MOLM-13 flank tumor growth, prevented tumor formation, regressed established MV-4-11 xenografts, and increased survival by 20 weeks in an MV-4-11 engraftment model. In tumors, ABT-869 inhibited FLT3 phosphorylation, induced apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]) and decreased proliferation (Ki67). ABT-869 is under clinical development for AML.

  10. Arabidopsis RADICAL-INDUCED CELL DEATH1 belongs to the WWE protein-protein interaction domain protein family and modulates abscisic acid, ethylene, and methyl jasmonate responses.

    Science.gov (United States)

    Ahlfors, Reetta; Lång, Saara; Overmyer, Kirk; Jaspers, Pinja; Brosché, Mikael; Tauriainen, Airi; Kollist, Hannes; Tuominen, Hannele; Belles-Boix, Enric; Piippo, Mirva; Inzé, Dirk; Palva, E Tapio; Kangasjärvi, Jaakko

    2004-07-01

    Experiments with several Arabidopsis thaliana mutants have revealed a web of interactions between hormonal signaling. Here, we show that the Arabidopsis mutant radical-induced cell death1 (rcd1), although hypersensitive to apoplastic superoxide and ozone, is more resistant to chloroplastic superoxide formation, exhibits reduced sensitivity to abscisic acid, ethylene, and methyl jasmonate, and has altered expression of several hormonally regulated genes. Furthermore, rcd1 has higher stomatal conductance than the wild type. The rcd1-1 mutation was mapped to the gene At1g32230 where it disrupts an intron splice site resulting in a truncated protein. RCD1 belongs to the (ADP-ribosyl)transferase domain-containing subfamily of the WWE protein-protein interaction domain protein family. The results suggest that RCD1 could act as an integrative node in hormonal signaling and in the regulation of several stress-responsive genes.

  11. An Orthogonal D2 O-Based Induction System that Provides Insights into d-Amino Acid Pattern Formation by Radical S-Adenosylmethionine Peptide Epimerases.

    Science.gov (United States)

    Morinaka, Brandon I; Verest, Marjan; Freeman, Michael F; Gugger, Muriel; Piel, Jörn

    2017-01-16

    Radical S-adenosyl methionine peptide epimerases (RSPEs) are an enzyme family that accomplishes regiospecific and irreversible introduction of multiple d-configured residues into ribosomally encoded peptides. Collectively, RSPEs can generate diverse epimerization patterns in a wide range of substrates. Previously, the lack of rapid methods to localize epimerized residues has impeded efforts to investigate the function and applicative potential of RSPEs. An efficient mass spectrometry-based assay is introduced that permits characterization of products generated in E. coli. Applying this to a range of non-natural peptide-epimerase combinations, it is shown that the d-amino acid pattern is largely but not exclusively dictated by the core peptide sequence, while the epimerization order is dependent on the enzyme-leader pair. RSPEs were found to be highly promiscuous, which allowed for modular introduction of peptide segments with defined patterns.

  12. Inhibitory effects of chitosan on superoxide anion radicals and lipid free radicals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the electron spin resonance (ESR) technique, the inhibitory effects of chitosan on superoxide anion radicals and linoleic acid lipid radicals were found. The inhibitory ratio E for these two kinds of radicals is in proportion to the concentration of chitosan. It was also observed that E for linoleic acid lipid radicals increased with the increase of the degree of deacetylation and decreased with the increase of the molecular weight of chitosan.

  13. Isolation of Lactic Acid Bacteria Showing Antioxidative and Probiotic Activities from Kimchi and Infant Feces.

    Science.gov (United States)

    Ji, Keunho; Jang, Na Young; Kim, Young Tae

    2015-09-01

    The purpose of this study was to investigate lactic acid bacteria with antioxidative and probiotic activities isolated from Korean healthy infant feces and kimchi. Isolates A1, A2, S1, S2, and S3 were assigned to Lactobacillus sp. and isolates A3, A4, E1, E2, E3, and E4 were assigned to Leuconostoc sp. on the basis of their physiological properties and 16S ribosomal DNA sequence analysis. Most strains were confirmed as safe bioresources through nonhemolytic activities and non-production of harmful enzymes such as β-glucosidase, β- glucuronidase and tryptophanase. The 11 isolates showed different resistance to acid and bile acids. In addition, they exhibited antibacterial activity against foodborne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Escherichia coli. Furthermore, all strains showed significantly high levels of hydrophobicity. The antioxidant effects of culture filtrates of the 11 strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity, 2.2'- azino-bis (2-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity, and superoxide dismutase activity. The results revealed that most of the culture filtrates have effective scavenging activity for DPPH and ABTS radicals. All strains appeared to have effective superoxide dismutase activity. In conclusion, the isolated strains A1, A3, S1, and S3 have significant probiotic activities applicable to the development of functional foods and health-related products. These strains might also contribute to preventing and controlling several diseases associated with oxidative stress, when used as probiotics.

  14. Reaction between protein radicals and other biomolecules

    DEFF Research Database (Denmark)

    Østdal, Henrik; Davies, Michael Jonathan; Andersen, Henrik J

    2002-01-01

    oil-in-water emulsion resulted in additional formation of lipid hydroperoxides and conjugated dienes. The results clearly show that protein radicals have to be considered as dynamic species during oxidative processes in biological systems and that protein radicals should not be considered as end-products......The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2....... Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid...

  15. The ratio of Mcl-1 and Noxa determines ABT737 resistance in squamous cell carcinoma of the skin.

    Science.gov (United States)

    Geserick, P; Wang, J; Feoktistova, M; Leverkus, M

    2014-09-11

    Tumour progression and therapy resistance in squamous cell carcinoma of the skin (SCC) is strongly associated with resistance to intrinsic mitochondrial apoptosis. We thus investigated the role of various anti-apoptotic Bcl-2 proteins for apoptosis protection in SCC using the BH3 agonist ABT737 that can overcome multidomain Bcl-2 protein protection. Sensitive SCC cells underwent rapid loss of mitochondrial membrane potential (MMP), subsequent apoptosis concomitant with caspase-3 activation and an early release of mitochondria-derived cytochrome c and smac/DIABLO. In contrast, ABT737 resistance in subsets of SCC cells was not explained by XIAP, important for protection from DR-induced apoptosis in SCC. Of note, ABT737 did not prime SCC cells to DR-induced apoptosis. Interestingly, the ratio of Mcl-1 and Noxa determined sensitivity to ABT737: loss of Mcl-1 rendered resistant cells sensitive to ABT737, whereas loss of Noxa promoted resistance in sensitive cells. In line, suppression of Mcl-1 by the pan-Bcl-2 inhibitor Obatoclax or overexpression of Noxa rendered resistant SCC cells sensitive to BH3 mimetics. Our data indicate that targeting of the Mcl-1/Noxa axis is important to overcome resistance to mitochondrial apoptosis in SCC. Therefore, combination treatment of ABT737 or derivatives with Mcl-1 inhibitors, or inducers of Noxa, may represent a novel option of targeted therapy in metastatic SCC of the skin.

  16. Evaluation of in vitro antioxidant activity and free radical scavenging potential of variety of Tagetes erecta L. flowers growing in Bulgaria

    Directory of Open Access Journals (Sweden)

    Miglena Valyova

    2012-08-01

    Full Text Available Summary. Marigold (Tagetes erecta L. is well known for its antimicrobial, antiseptic, wound and ulcer healing, antiinflammatory, antioxidant and antiviral properties, and it has a long history of being used as an herbal remedy. T. erecta L. produces a variety of substances that possess pharmacological effects and antioxidant activity. The present study was therefore aimed to analyze the antioxidant activity of extracts and fractions of T. erecta L. flowers, cultivated in Bulgaria. Radical scavenging potential was determined using two different in vitro assays. 1, 1-diphenyl-2-picrylhydrazyl (DPPH and 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS radicals. The ethyl acetate fraction of T. erecta L. ethanol extract was found to be the most effective in both assays, DPPH (IC50 4.3±0.4 μg/ml and ABTS (0.8±0.2 TEAC. The greatest total phenolic content was detected in EtOAc fraction from EtOH extract (517.8 mg/g GAE. It was obtained high quantity of ascorbate and ascorbate/dehydroascorbate ratio more than 1. The quantity of glutathione reduced is low and glutathione reduced/glutathione oxidized ratio was lower than 1. A correlation between radical scavenging capacities of samples with total phenolic compound content was observed. The present study revealed that the EtOAc fraction effectively show the best ability to scavenge the free radicals. Industrial relevance. Herbal medicines have gained increasing attention worldwide for the treatment of chronic diseases because of their effectiveness and small side effects as compared to synthetic drugs.Recently, an attention has been directed toward the antioxidant phytochemicals which have proved as protective against cardiovascular diseases and cancer, associated with overproduction of reactive oxygen species. The present investigations focus has been to discover plant extracts and fractions from T. erecta useful to prevent chronic degenerative diseases, especially those mediated by

  17. Solvent effects on the antioxidant capacity of lipophilic and hydrophilic antioxidants measured by CUPRAC, ABTS/persulphate and FRAP methods.

    Science.gov (United States)

    Celik, Saliha Esin; Ozyürek, Mustafa; Güçlü, Kubilay; Apak, Reşat

    2010-06-15

    Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g., fats, lipids, proteins, and DNA) from the damage of reactive oxygen species (ROS). Solvent effect is a crucial parameter on the chemical behaviour of antioxidant compounds but there has been limited information regarding its role on antioxidant capacity and its assays. Therefore, the present study was undertaken to investigate the total antioxidant capacity (TAC) of some certain lipophilic and hydrophilic antioxidants, measured in different solvent media such as ethanol (EtOH) (100%), methanol (MeOH) (100%), methanol/water (4:1, v/v), methanol/water (1:1, v/v), dichloromethane (DCM)/EtOH (9:1, v/v). The cupric reducing antioxidant capacity (CUPRAC) values of selected antioxidants were experimentally reported in this work as trolox equivalent antioxidant capacity (TEAC), and compared to those found by reference TAC assays, i.e., 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/persulphate (ABTS/persulphate) and ferric reducing antioxidant power (FRAP) methods. The TAC values of synthetic mixtures of antioxidants were experimentally measured as trolox equivalents and compared to those theoretically found by making use of the principle of additivity of absorbances assuming no chemical interaction between the mixture constituents. Possible synergistic (e.g., BHT and BHA in DCM/EtOH) or antagonistic behaviours of these synthetic mixtures were investigated in relation to solvent selection.

  18. Exploiting the synergy between carboplatin and ABT-737 in the treatment of ovarian carcinomas.

    KAUST Repository

    Jain, Harsh Vardhan

    2014-01-06

    Platinum drug-resistance in ovarian cancers mediated by anti-apoptotic proteins such as Bcl-xL is a major factor contributing to the chemotherapeutic resistance of recurrent disease. Consequently, concurrent inhibition of Bcl-xL in combination with chemotherapy may improve treatment outcomes for patients. Here, we develop a mathematical model to investigate the potential of combination therapy with ABT-737, a small molecule inhibitor of Bcl-xL, and carboplatin, a platinum-based drug, on a simulated tumor xenograft. The model is calibrated against in vivo experimental data, wherein xenografts established in mice were treated with ABT-737 and/or carboplatin on a fixed periodic schedule. The validated model is used to predict the minimum drug load that will achieve a predetermined level of tumor growth inhibition, thereby maximizing the synergy between the two drugs. Our simulations suggest that the infusion-duration of each carboplatin dose is a critical parameter, with an 8-hour infusion of carboplatin given weekly combined with a daily bolus dose of ABT-737 predicted to minimize residual disease. The potential of combination therapy to prevent or delay the onset of carboplatin-resistance is also investigated. When resistance is acquired as a result of aberrant DNA-damage repair in cells treated with carboplatin, drug delivery schedules that induce tumor remission with even low doses of combination therapy can be identified. Intrinsic resistance due to pre-existing cohorts of resistant cells precludes tumor regression, but dosing strategies that extend disease-free survival periods can still be identified. These results highlight the potential of our model to accelerate the development of novel therapeutics such as BH3 mimetics.

  19. [The effect of fenofibrate on expression of genes involved in fatty acids beta-oxidation and associated free-radical processes].

    Science.gov (United States)

    Gureev, A P; Shmatkova, M L; Bashmakov, V Yu; Starkov, A A; Popov, V N

    2016-05-01

    Fenofibrate is a synthetic ligand for peroxisome proliferator-activated receptors subtype alpha (PPARa); it is used for the treatment of a wide range of metabolic diseases such as hypertriglyceridemia, dyslipidemia, diabetes and various neurodegenerative diseases. We have studied the effect of fenofibrate on b-oxidation of fatty acids and related free-radical processes. The most effective concentration of fenofibrate (0.3%) added to the chow caused a significant decrease of the body weight of mice. The data obtained by quantitative PCR demonstrated increased hepatic gene expression responsible for b-oxidation of fatty acids in peroxisomes and mitochondria. Enhancement of oxidative processes caused a 2-fold increase in the rate of reactive oxygen species (ROS) production, as evidenced by determination of the level of lipid peroxidation (LPO) products in the liver. Mitochondrial antioxidant systems are more sensitive to elevated ROS production, as they respond by increased expression of SOD2 and PRDX3 genes, than cytoplasmic and peroxisomal antioxidant systems, where expression of CAT1, SOD1, PRDX5 genes remained unaltered.

  20. Radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Sønksen, Jens; Jakobsen, Henrik

    2014-01-01

    OBJECTIVE: The aim of this study was to compare oncological and functional outcomes between robot-assisted laparoscopic radical prostatectomy (RALP) and retropubic radical prostatectomy (RRP) during the initial phase with RALP at a large university hospital. MATERIAL AND METHODS: Patient and tumour...... surgery and at follow-up and they were asked to report their use of pads/diapers. Potency was defined as an IIEF-5 score of at least 17 with or without phosphodiesterase-5 inhibitors. Patients using up to one pad daily for security reasons only were considered continent. Positive surgical margins, blood...... loss and functional outcomes were compared between groups. RESULTS: Overall, 453 patients were treated with RRP and 585 with RALP. On multivariate logistic regression analyses, the type of surgery did not affect surgical margins (p = 0.96) or potency at 12 months (p = 0.7). Patients who had undergone...

  1. Platinum compounds sensitize ovarian carcinoma cells to ABT-737 by modulation of the Mcl-1/Noxa axis.

    Science.gov (United States)

    Simonin, Karin; N'Diaye, Monique; Lheureux, Stéphanie; Loussouarn, Claire; Dutoit, Soizic; Briand, Mélanie; Giffard, Florence; Brotin, Emilie; Blanc-Fournier, Cécile; Poulain, Laurent

    2013-04-01

    Ovarian cancer is the leading cause of death from gynecological cancer. The anti-apoptotic protein Bcl-x(L) is frequently overexpressed in ovarian carcinoma which correlates with chemotherapy resistance. It has been demonstrated that Bcl-x(L) cooperates with another anti-apoptotic protein, Mcl-1, to protect ovarian cancer cells against apoptosis, and that their concomitant inhibition induces massive cell death. Here, we examined the interest of ABT-737, a potent BH3-mimetic molecule targeting Bcl-x(L), both alone and in combination with Mcl-1 modulators, in ovarian cancer cell lines. As a single agent, ABT-737 was ineffective at promoting cell death in the four cell lines we tested in vitro. However, the specific inhibition of Mcl-1 by siRNA dramatically increased the sensitivity of chemoresistant cells to ABT-737. Platinum compounds also sensitize to ABT-737 by dose-dependently decreasing Mcl-1 expression or by increasing the expression of pro-apoptotic BH3-only proteins Noxa and, to a lower extent, Bim. Furthermore, we demonstrated that Noxa accumulation was involved in apoptosis occurring in response to the combination of ABT-737 and platinum compounds, since cells were protected from apoptosis by its silencing. Moreover, the combination was also highly cytotoxic ex vivo in sliced SKOV3 tumor nodes. However we observed in these slices a strong basal expression of Noxa and apoptotic cell death in response to ABT-737 alone. Therefore, we have revealed that the modulation of the Mcl-1/Noxa axis by platinum compounds results in a strong sensitization of chemoresistant ovarian carcinoma cells to ABT-737, which could constitute a promising therapeutic in these cancers.

  2. 抗HCV新药sofosbuvir和ABT-450研究进展%Research progress of sofosbuvir and ABT-450, the newest direct-acting anti-HCV agents

    Institute of Scientific and Technical Information of China (English)

    曾庆磊; 李元元; 王福生

    2013-01-01

    长期以来,聚乙二醇干扰素α联合利巴韦林是治疗慢性丙型肝炎的标准疗法,但HCV基因1、4型患者的持续病毒学应答率仅为40%~50%,基因2、3、5、6型患者约为80%.所以,提高临床疗效成为临床医生最为关注的问题.近年来不断有新研发的小分子直接抗病毒药物(direct-acting antiviral agents,DAAs)问世,临床试验表明DAAs更具特异性和有效性,且疗程短,不良反应少.本文简要介绍抗HCV药物的发展历程以及2013年1月在上报道的2种最新药物sofosbuvir和ABT-450的临床试验结果,并展望未来抗HCV的临床研究方向.%Combination therapy with pegylated interferon a and ribavirin has been the standard of care for chronic hepatitis C for years. But sustained virological response rates in patients with HCV genotype 1, 4 and genotype 2, 3, 5, 6 are 40%-50% and about 80%, respectively. Therefore, how to improve clinical efficacy is the most important concern of clinical physicians. In recent years, several direct-acting antiviral agents (DAAs) have been developed, and clinical trials have shown that DAAs are characterized by greater specificity and effectiveness, shorter duration of treatment and fewer adverse reactions. The authors briefly introduce the development history of and -HCV agents and the clinical efficacy of sofosbuvir and ABT-450, which were reported in the literatures published on New England Journal of Medicine in Jan. 2013, and point out the prospect of and-HCV clinical research.

  3. Correlation of polyphenolic content with radical-scavenging capacity and anthelmintic effects of Rubus ulmifolius (Rosaceae) against Haemonchus contortus.

    Science.gov (United States)

    Akkari, Hafidh; Hajaji, Soumaya; B'chir, Fatma; Rekik, Mourad; Gharbi, Mohamed

    2016-05-15

    Phenolic content, antioxidant and anthelmintic activities of herbal extracts are of particular interest to drug industry; plant extracts with significant anthelmintic activity have the potential to be used as alternatives to conventional chemical drugs. In the present study, Rubus ulmifolius fruit extracts obtained using solvents of increasing polarity (water, methanol, chloroform and hexane) were examined for their antioxidant and anthelmintic activities in correlation with their polyphenolic content. In vitro antioxidant activity of all extracts was carried out using free radical-scavenging activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethilenebenzotiazolin)-6-sulfonic acid (ABTS) radical cation. In vitro anthelmintic activities were investigated on the egg and adult worms of Haemonchus contortus from sheep in comparison to albendazole. Total polyphenol content of R. ulmifolius was higher in more polar extract, ranging from 64.5 in aqueous extract to 1.57 mg gallic acid equivalents per gram of dry weight (GAE/g DW) in hexanic extract. Likewise, highest amounts of flavonoids and condensed tannins were found in aqueous extract (28.06 mg QE/g and 7.42 mg CE/g DW, respectively) compared to hexanic extract (0.71 mg QE/g and 0.29 mg CE/g DW, respectively) (pIC50) range values were similar for both assays (2.13-45.54 μg/mL and 1.2-43.82 μg/mL, respectively). All plant extracts showed ovicidal activity at all tested concentrations. Fruit methanolic (IC50=2.76mg/mL) and aqueous (IC50=2.08 mg/mL) extracts showed higher inhibitory effects than chloroformic (IC50=7.62 mg/mL) and hexanic (IC50=12.93 mg/mL) extracts on egg hatching (p<0.05). There was a significant correlation of total polyphenol, flavonoids and tannins content with scavenging of either DPPH (r=0.722, 0.764 and 0.752, p<0.01, respectively) or ABTS radicals (r=0.893, 0.765 and 0.722, p<0.01, respectively) and with inhibition of egg hatching (r=0.874, 0.883 and 0.862, p<0

  4. Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid

    Directory of Open Access Journals (Sweden)

    Castellano, J. M.

    2016-09-01

    Full Text Available This work investigates the role of oleanolic acid (OA, isolated from the olive (Olea europaea L. leaf, as a radical scavenger and inhibitor of the hydrolyzing enzymes of dietary carbohydrates. New evidence is provided showing that OA may capture 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid and peroxyl radicals, and also exert a strong and non -competitive inhibition of α-glucosidase (IC50 10.11 ± 0.30 μM. The kinetic and spectrometric analyses performed indicate that OA interacts with this enzyme inside a hydrophobic pocket, through an endothermic and non spontaneous process of a hydrophobic nature. These are two possible mechanisms by which OA may facilitate a better control of post-prandial hyperglycaemia and oxidative stress, so contributing to preserving insulin signalling. Obesity, insulin resistance and Type 2 Diabetes Mellitus are considered the first pandemics of the 21st century. In this sense, OA might be used in future preventive and therapeutic strategies, as an ingredient in new drugs and functional foods.Este trabajo estudia el papel del ácido oleanólico (OA, aislado de la hoja de olivo, como secuestrador de radicales libres e inhibidor de enzimas implicados en la hidrolisis de los carbohidratos de la dieta, dos mecanismos por los que el triterpeno podría mitigar la hiperglicemia postprandial y el estrés oxidativo. Se aportan nuevas evidencias que muestran que el OA puede capturar radicales ácido 2,2’-azino-bis-(3-etilbenzotiazolín-6-sulfónico y peroxilo, y que ejerce una potente inhibición no-competitiva de α-glucosidasa (IC50 10.11±0.30 μM. El análisis cinético y espectrométrico llevado a cabo indica que OA interacciona con este enzima en el interior de un bolsillo hidrofóbico, mediante un proceso endotérmico no espontáneo, de naturaleza hidrofóbica. Estos son dos posibles mecanismos por los cuales el OA puede facilitar un mejor control de la hiperglucemia postprandial y el estrés oxidativo

  5. Protective Effect of Sinapine against Hydroxyl Radical-Induced Damage to Mesenchymal Stem Cells and Possible Mechanisms.

    Science.gov (United States)

    Li, Xican; Han, Lu; Li, Yunrong; Zhang, Jing; Chen, Jiemin; Lu, Wenbiao; Zhao, Xiaojun; Lai, Yingtao; Chen, Dongfeng; Wei, Gang

    2016-01-01

    As a phenolic alkaloid occurring in Cruciferous plants, sinapine was observed to protect mesenchymal stem cells (MSCs) against ·OH-induced damage in this study. It was also found to prevent DNA from damage, to scavenge various free radicals (·OH, ·O2(-), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) (ABTS)(+·), and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)), and to reduce Cu(2+) to Cu(+). To further explore the mechanism, the end-product of sinapine reaction with DPPH· was determined using HPLC-electrospray ionization (ESI)-MS/MS and HPLC-diode array detector (DAD). Four molecular ion peaks (m/z 701, 702, 703, and 351) in HPLC-ESI-MS/MS analysis indicated a radical adduct formation (RAF) pathway; while a bathochromic shift (λ(max) 334→475 nm) in HPLC-DAD indicated the formation of quinone as the oxidized product of the phenolic -OH group. Based on these results, it may be concluded that, (i) sinapine can effectively protect against ·OH-induced damage to DNA and MSCs; such protective effect may provide evidence for a potential role for sinapine in MSC transplantation therapy, and be responsible for the beneficial effects of Cruciferous plants. (ii) The possible mechanism for sinapine to protect against ·OH-induced oxidative damage is radical-scavenging, which is thought to be via hydrogen atom (H·) transfer (HAT) (or sequential electron (e) proton transfer (SEPT))→RAF pathways.

  6. MLN2238 synergizes BH3 mimetic ABT-263 in castration-resistant prostate cancer cells by induction of NOXA.

    Science.gov (United States)

    Wei, Xinghua; Zhou, Ping; Lin, Xuanting; Lin, Yurong; Wu, Sifeng; Diao, Pengfei; Xie, Haiqing; Xie, Keji; Tang, Ping

    2014-10-01

    Patients undergoing androgen blockade therapy develop castration-resistant prostate cancer (CRPC), which is associated with Bcl-2 upregulation and results in disease progression and death. In recent years, promising therapeutic agents, such as the BH3-only mimetic ABT-263 and proteasome inhibitors, have been developed and widely evaluated against a broad spectrum of cancer types, including prostate cancer, alone or in combination with other chemotherapeutic agents. In this study, the antitumor efficacy of ABT-263 and MLN2238 were evaluated as single agents and in combination in four CRPC cell lines: PC3, C4-2B, C4-2, and DU145. The viability of the treated cells and markers of apoptosis were assayed. Protein-protein interactions were analyzed by co-immunoprecipitation in drug-treated cells. Lentivirus-mediated short hairpin RNA was used to knockdown Bax, Mcl-1, and NOXA expressions. We found that ABT-263 and MLN2238 alone exhibited a mild cytotoxicity, and in combination, they elicited a synergistic cytotoxic effect in CRPC cells. The cell apoptosis induced by the combination drug treatment was evidenced by enhanced caspase-3 and Poly (ADP-ribose) polymerase (PARP) cleavage, and annexin-V-positive staining was significantly depleted by Bax knockdown. MLN2238 treatment upregulated NOXA and Mcl-1 expression, leading NOXA/Mcl-1 complexes to disassociate Bak from its complexes with Mcl-1 and enhancing ABT263-triggered Bax activation. NOXA knockdown by short hairpin RNA significantly attenuated the cytotoxicity of ABT-263 and MLN2238 co-administration. In conclusion, MLN2238 and ABT-263 synergistically triggered apoptosis in CRPC cells by upregulating NOXA and activating Bax, indicating a promising therapeutic strategy for the treatment of CRPC.

  7. Hydrogen atom transfer from 1,n-alkanediamines to the cumyloxyl radical. Modulating C-H deactivation through acid-base interactions and solvent effects.

    Science.gov (United States)

    Milan, Michela; Salamone, Michela; Bietti, Massimo

    2014-06-20

    A time-resolved kinetic study on the effect of trifluoroacetic acid (TFA) on the hydrogen atom transfer (HAT) reactions from 1,n-alkanediamines (R2N(CH2)nNR2, R = H, CH3; n = 1-4), piperazine, and 1,4-dimethylpiperazine to the cumyloxyl radical (CumO(•)), has been carried out in MeCN and DMSO. Very strong deactivation of the α-C-H bonds has been observed following nitrogen protonation and the results obtained have been explained in terms of substrate basicity, of the distance between the two basic centers and of the solvent hydrogen bond acceptor ability. At [substrate] ≤ 1/2 [TFA] the substrates exist in the doubly protonated form HR2N(+)(CH2)nN(+)R2H, and no reaction with CumO(•) is observed. At 1/2 [TFA] [TFA], HAT occurs from the α-C-H bonds of R2N(CH2)nNR2, and the mesured kH values are very close to those obtained in the absence of TFA. Comparison between MeCN and DMSO clearly shows that in the monoprotonated diamines R2N(CH2)nN(+)R2H remote C-H deactivation can be modulated through solvent hydrogen bonding.

  8. Phase 1 Study of ABT-751 in Combination With CAPIRI (Capecitabine and Irinotecan) and Bevacizumab in Patients With Advanced Colorectal Cancer.

    Science.gov (United States)

    Rudek, Michelle A; Dasari, Arvind; Laheru, Daniel; He, Ping; Jin, Runyan; Walker, Rosalind; Taylor, Gretchen E; Jimeno, Antonio; Donehower, Ross C; Hidalgo, Manuel; Messersmith, Wells A; Purcell, W Thomas

    2016-08-01

    ABT-751 is an orally bioavailable sulfonamide with antimitotic properties. A nonrandomized phase 1 dose-escalation study of ABT-751 in combination with CAPIRI (capecitabine and irinotecan) and bevacizumab was conducted to define the maximum tolerated dose, dose-limiting toxicity (DLT), and pharmacokinetics in patients with advanced colorectal cancer. Patients were treated with ABT-751 daily for 7 days (alone) and then began 21-day cycles of treatment with ABT-751 daily and capecitabine twice daily for 14 days plus irinotecan on day 1 intravenously. Bevacizumab was added as standard of care at 7.5 mg/kg on day 1 after the first 2 dose levels. Because of intolerance to the regimen, a reduced dose of ABT-751 was also explored with reduced-dose and full-dose CAPIRI with bevacizumab. ABT-751 and irinotecan pharmacokinetics, ABT-751 glucuronidation, and protein binding were explored. Twenty-four patients were treated over 5 dose levels. The maximum tolerated dose was ABT-751 125 mg combined with full-dose CAPIRI and bevacizumab 7.5 mg/kg on day 1. DLTs were hypokalemia, elevated liver tests, and febrile neutropenia. ABT-751 is metabolized by UGT1A8 and to a lesser extent UGT1A4 and UGT1A1. Irinotecan and APC exposure were increased, SN-38 exposure was similar, and SN-38 glucuronide exposure was decreased. Clinically relevant alterations in ABT-751 and irinotecan pharmacokinetics were not observed. Despite modest efficacy, the combination of ABT-751, CAPIRI, and bevacizumab will not be studied further in colorectal cancer.

  9. Cupric ion reducing antioxidant capacity assay for antioxidants in human serum and for hydroxyl radical scavengers.

    Science.gov (United States)

    Apak, Reşat; Güçlü, Kubilay; Ozyürek, Mustafa; Bektaşoğlu, Burcu; Bener, Mustafa

    2010-01-01

    Tests measuring the combined antioxidant effect of the nonenzymatic defenses in biological fluids may be useful in providing an index of the organism's capability to counteract reactive species known as pro-oxidants, resist oxidative damage, and combat oxidative stress-related diseases. The selected chromogenic redox reagent for the assay of human serum should be easily accessible, stable, selective, and respond to all types of biologically important antioxidants such as ascorbic acid, alpha-tocopherol, beta-carotene, reduced glutathione (GSH), uric acid, and bilirubin, regardless of chemical type or hydrophilicity. Our recently developed cupric reducing antioxidant capacity (CUPRAC) spectrophotometric method for a number of polyphenols and flavonoids using the copper(II)-neocuproine reagent in ammonium acetate buffer is now applied to a complete series of plasma antioxidants for the assay of total antioxidant capacity of serum, and the resulting absorbance at 450 nm is recorded either directly (e.g., for ascorbic acid, alpha-tocopherol, and glutathione) or after incubation at 50 degrees C for 20 min (e.g., for uric acid, bilirubin, and albumin), quantitation being made by means of a calibration curve. The lipophilic antioxidants, alpha-tocopherol and beta-carotene, are assayed in dichloromethane. Lipophilic antioxidants of serum are extracted with n-hexane from an ethanolic solution of serum subjected to centrifugation. Hydrophilic antioxidants of serum are assayed in the centrifugate after perchloric acid precipitation of proteins. The CUPRAC molar absorptivities, linear ranges, and TEAC (trolox equivalent antioxidant capacity) coefficients of the serum antioxidants are established, and the results are evaluated in comparison with the findings of the ABTS/TEAC reference method. The intra- and inter-assay coefficients of variation (CVs) are 0.7 and 1.5%, respectively, for serum. The CUPRAC assay proved to be efficient for glutathione and thiol-type antioxidants

  10. Noxa determines localization and stability of MCL-1 and consequently ABT-737 sensitivity in small cell lung cancer.

    Science.gov (United States)

    Nakajima, W; Hicks, M A; Tanaka, N; Krystal, G W; Harada, H

    2014-02-13

    The sensitivity to ABT-737, a prototype BH3 mimetic drug, varies in a broad range in small cell lung cancer (SCLC) cells. We have previously shown that the expression of Noxa, a BH3-only pro-apoptotic BCL-2 family protein, is the critical determinant of ABT-737 sensitivity. We show here that Noxa regulates the localization and stability of MCL-1, an anti-apoptotic member, which results in modulating ABT-737 sensitivity. Mutations in Noxa within the BH3 domain, the carboxyl terminus mitochondrial targeting domain, or of ubiquitinated lysines not only change the localization and stability of Noxa itself but also affect the mitochondrial localization and phosphorylation/ubiquitination status of MCL-1 and consequently modulate sensitivity to ABT-737. Results of studies utilizing these mutant proteins indicate that Noxa recruits MCL-1 from the cytosol to the mitochondria. Translocation of MCL-1 initiates its phosphorylation and subsequent ubiquitination, which triggers proteasome-mediated degradation. The precise regulatory mechanisms of Noxa/MCL-1 expression and stability could provide alternative targets to modulate apoptosis induced by BH3 mimetic drugs or other chemotherapeutic reagents.

  11. Antioxidant properties of neohesperidin dihydrochalcone: inhibition of hypochlorous acid-induced DNA strand breakage, protein degradation, and cell death.

    Science.gov (United States)

    Choi, Je-Min; Yoon, Byoung-Seok; Lee, Sang-Kyou; Hwang, Jae-Kwan; Ryang, Ryung

    2007-02-01

    Neohesperidin dihydrochalcone (NHDC), a non-nutritive sweetening agent, is simply produced by hydrogenation of neohesperidin. The aim of this study is to evaluate the antioxidant and radical scavenging properties of neohesperidin dihydrochalcone and other structurally related compounds (phloridzin, neohesperidin) toward different reactive radical and oxygen species including .ABTS+, .O2-, .OH, H2O2, and HOCl in vitro. NHDC showed remarkable radical scavenging activity against stable radical and reactive oxygen species (ROS) in concentration dependent manner. Especially, NHDC was the most potent inhibitor of H2O2 and HOCl. NHDC showed HOCl scavenging activity of 93.5% and H2O2 scavenging property of 73.5% which was more than those of all the tested compounds including ascorbic acid and BHT. Moreover, NHDC could inhibit protein degradation, plasmid DNA strand cleavage and HIT-T15, HUVEC cell death from HOCl attack while mannitol, BHT, and ascorbic acid could not protect them effectively. These results suggest that NHDC is a potent antioxidant, especially it is evaluated as a novel HOCl scavenger. This study implies the possibility of therapeutic effect of NHDC on ROS-related inflammatory diseases.

  12. ANTIOXIDANT CAPACITY AND AMINO ACID PROFILES OF EGG TOFU

    Directory of Open Access Journals (Sweden)

    Maizura Murad

    2013-01-01

    Full Text Available Tofu contains high quality protein source and antioxidant which could reduce risk of cancer. This research aims to determine the effect of soymilk and egg ratios on the antioxidant capacity, daidzein and genistein content and amino acid profiles of egg tofu. Egg tofu was prepared using soymilk and fresh egg in ratios of 1:1, 2:1, 3:1 and 4:1. Glucono-Delta-Lactone (GDL was added in the egg tofu to act as a coagulating agent. Increased of soymilk at all ratios had significantly (p<0.05 increased in Ferric-Reducing Antioxidant Power (FRAP, daidzein and genistein content of egg tofu. Conversely, decreased in soymilk ratio had significantly (p<0.05 increased the radical scavenging activities of the 2,2-Azino-Bis 3-ethylbenzothiazoline-6-Sulfonic acid (ABTS and 2,2-Diphenyl-2-Picrylhydrazyl (DPPH in egg tofu. Increased of soymilk ratio up to 3:1 caused decreased in amino acid methionine (met and cystein (cys significantly (p<0.05. A significant (p<0.01 and a positive correlation was observed between Total Phenolic Content (TPC and FRAP (r = 0.93. However, there was a negative (p<0.01 correlation between TPC and DPPH (r = -0.83. The antioxidant capacity of egg tofu in DPPH assay showed a positive and significant (p<0.01 correlation with cysteine, methionine and tryptophan with r value of 0.92, 0.93 and 0.96 respectively. Higher content of egg in egg tofu had contributed to the increased of antioxidant capacity as indicated in DPPH assay and ABTS assay as well as amino acid methionine and cysteine.

  13. Ignorance Radicalized

    Directory of Open Access Journals (Sweden)

    Gergo Somodi

    2009-12-01

    Full Text Available The aim of this paper is twofold. I criticize Michael Devitt's linguistic---as opposed to Chomsky's psychological---conception of linguistics on the one hand, and I modify his related view on linguistic intuitions on the other. I argue that Devitt's argument for the linguistic conception is in conflict with one of the main theses of that very conception, according to which linguistics should be about physical sentence tokens of a given language rather than about the psychologically real competence of native speakers. The basis of this conflict is that Devitt's view on language, as I will show, inherits too much from the criticized Chomskian view. This is also the basis of Devitt's strange claim that it is the linguist, and not the ordinary speaker, whose linguistic intuition should have an evidential role in linguistics. I will argue for the opposite by sketching a view on language that is more appropriate to the linguistic conception. That is, in criticizing Devitt, I am not defending the Chomskian approach. My aim is to radicalize Devitt's claims.

  14. Strong Inhibition of O-Atom Transfer Reactivity for Mn(IV)(O)(π-Radical-Cation)(Lewis Acid) versus Mn(V)(O) Porphyrinoid Complexes.

    Science.gov (United States)

    Zaragoza, Jan Paulo T; Baglia, Regina A; Siegler, Maxime A; Goldberg, David P

    2015-05-27

    The oxygen atom transfer (OAT) reactivity of two valence tautomers of a Mn(V)(O) porphyrinoid complex was compared. The OAT kinetics of Mn(V)(O)(TBP8Cz) (TBP8Cz = octakis(p-tert-butylphenyl)corrolazinato(3-)) reacting with a series of triarylphosphine (PAr3) substrates were monitored by stopped-flow UV-vis spectroscopy, and revealed second-order rate constants ranging from 16(1) to 1.43(6) × 10(4) M(-1) s(-1). Characterization of the OAT transition state analogues Mn(III)(OPPh3)(TBP8Cz) and Mn(III)(OP(o-tolyl)3)(TBP8Cz) was carried out by single-crystal X-ray diffraction (XRD). A valence tautomer of the closed-shell Mn(V)(O)(TBP8Cz) can be stabilized by the addition of Lewis and Brønsted acids, resulting in the open-shell Mn(IV)(O)(TBP8Cz(•+)):LA (LA = Zn(II), B(C6F5)3, H(+)) complexes. These Mn(IV)(O)(π-radical-cation) derivatives exhibit dramatically inhibited rates of OAT with the PAr3 substrates (k = 8.5(2) × 10(-3) - 8.7 M(-1) s(-1)), contrasting the previously observed rate increase of H-atom transfer (HAT) for Mn(IV)(O)(TBP8Cz(•+)):LA with phenols. A Hammett analysis showed that the OAT reactivity for Mn(IV)(O)(TBP8Cz(•+)):LA is influenced by the Lewis acid strength. Spectral redox titration of Mn(IV)(O)(TBP8Cz(•+)):Zn(II) gives Ered = 0.69 V vs SCE, which is nearly +700 mV above its valence tautomer Mn(V)(O)(TBP8Cz) (Ered = -0.05 V). These data suggest that the two-electron electrophilicity of the Mn(O) valence tautomers dominate OAT reactivity and do not follow the trend in one-electron redox potentials, which appear to dominate HAT reactivity. This study provides new fundamental insights regarding the relative OAT and HAT reactivity of valence tautomers such as M(V)(O)(porph) versus M(IV)(O)(porph(•+)) (M = Mn or Fe) found in heme enzymes.

  15. Radical formation by heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Beuter, W.

    1982-09-01

    Certain reduced heavy metal ions can convert oxygen to a ''reactive oxygen species'' by donation of an electron. The reactive oxygen then attacks structures susceptible to oxidation, in particular unsaturated fatty acids, and peroxidizes them in a radical reaction. This process is inhibited by the presence of vitamin E and by other means. Peroxidized lipids decay forming free radicals in the process which themselves can peroxidise neighbouring lipids in a radical chain reaction. This decay is, moreover, catalysed by reduced heavy metal ions but on the other hand retarded by selenium-containing glutathione peroxidase. Radical formation by heavy metals is considerably involved in (i) the production of parenteral iron poisoning of the piglet (ii) haemolytic crisis occurring in ruminants through chronic copper poisoning (iii) the production of lead poisoning in ruminants and other animals. These types of poisonings are made worse by a deficiency of vitamin E and/or selenium. Factors which increase the bio-availability of the free heavy metal ion or reduce the redox potential thereof can aid radical formation as well as factors which lead to a reduction of the heavy metal ion e.g. cysteine, ascorbic acid or glucose.

  16. (S)-3-methyl-5-(1-methyl-2-pyrrolidinyl)isoxazole (ABT 418): a novel cholinergic ligand with cognition-enhancing and anxiolytic activities: II. In vivo characterization.

    Science.gov (United States)

    Decker, M W; Brioni, J D; Sullivan, J P; Buckley, M J; Radek, R J; Raszkiewicz, J L; Kang, C H; Kim, D J; Giardina, W J; Wasicak, J T

    1994-07-01

    (S)-3-methyl-5-(1-methyl-2-pyrrolidinyl)isoxazole (ABT 418), an isoxazole analog of (-)-nicotine, is a potent agonist at the alpha-4/beta-2 subtype of neuronal nicotinic acetylcholine receptor (nAChR) that exists in mammalian brain (Arneric et al., 1994). Compared to (-)-nicotine, ABT 418 has reduced potency to interact with the subunit isoforms of nAChR found in sympathetic ganglia, and it does not compete for alpha-bungarotoxin binding sites in brain or at the neuromuscular junction. ABT 418 [minimum effective dose (MED), 0.062 mumol/kg i.p.) was 10-fold more potent in improving retention of avoidance learning in normal mice than (-)-nicotine, whereas the (R)-enantiomer of ABT 418, A-81754, was inactive. The memory-enhancing effect of ABT 418 was prevented by the nAChR channel blocker, mecamylamine. In the elevated plus-maze model of anxiety, ABT 418 (MED, 0.19 mumol/kg i.p.) increased open-arm exploration in mice, as previously shown for (-)-nicotine (MED, 0.62 mumol/kg i.p.). A-81754, did not have anxiolytic-like effects in this test. Unlike the classical anxiolytic, diazepam, ABT 418 did not impair rotorod performance in the dose range where beneficial effects occurred. In rats, ABT 418 (MED, 0.002 mumol/kg i.v.) was remarkably potent in enhancing basal forebrain-elicited increases in cortical cerebral blood flow, whereas resting cerebral blood flow was unaffected. Free running cortical electroencephalography in rats was unaffected by ABT 418 at a dose of 1.9 mumol/kg i.p., whereas the same dose of (-)-nicotine caused cortical activation (decreased power in the 1-13 Hz range and increased power in the 25-50 Hz range). Whereas ABT 418 was approximately 3- to 10-fold more potent than (-)-nicotine in memory enhancement and anxiolytic test paradigms, the compound had less emetic liability in dogs as compared to (-)-nicotine, and was less potent than (-)-nicotine in eliciting hypothermia, seizures, death and reduction of locomotor activity in mice. The measured

  17. Reactivity and selectivity patterns in hydrogen atom transfer from amino acid C-H bonds to the cumyloxyl radical: polar effects as a rationale for the preferential reaction at proline residues.

    Science.gov (United States)

    Salamone, Michela; Basili, Federica; Bietti, Massimo

    2015-04-03

    Absolute rate constants for hydrogen atom transfer (HAT) from the C-H bonds of N-Boc-protected amino acids to the cumyloxyl radical (CumO(•)) were measured by laser flash photolysis. With glycine, alanine, valine, norvaline, and tert-leucine, HAT occurs from the α-C-H bonds, and the stability of the α-carbon radical product plays a negligible role. With leucine, HAT from the α- and γ-C-H bonds was observed. The higher kH value measured for proline was explained in terms of polar effects, with HAT that predominantly occurs from the δ-C-H bonds, providing a rationale for the previous observation that proline residues represent favored HAT sites in the reactions of peptides and proteins with (•)OH. Preferential HAT from proline was also observed in the reactions of CumO(•) with the dipeptides N-BocProGlyOH and N-BocGlyGlyOH. The rate constants measured for CumO(•) were compared with the relative rates obtained previously for the corresponding reactions of different hydrogen-abstracting species. The behavior of CumO(•) falls between those observed for the highly reactive radicals Cl(•) and (•)OH and the significantly more stable Br(•). Taken together, these results provide a general framework for the description of the factors that govern reactivity and selectivity patterns in HAT reactions from amino acid C-H bonds.

  18. Solid state drug-polymer miscibility studies using the model drug ABT-102.

    Science.gov (United States)

    Jog, Rajan; Gokhale, Rajeev; Burgess, Diane J

    2016-07-25

    Amorphous solid dispersions typically suffer storage stability issues due to: their amorphous nature, high drug loading, uneven drug:stabilizer ratio and plasticization effects as a result of hygroscopic excipients. An extensive solid state miscibility study was conducted to aid in understanding the mechanisms involved in drug/stabilizer interactions. ABT-102 (model drug) and nine different polymers with different molecular weights and viscosities were selected to investigate drug/polymer miscibility. Three different polymer:drug ratios (1:3, 1:1 and 3:1, w/w) were analyzed using: DSC, FTIR and PXRD. Three different techniques were used to prepare the amorphous solid dispersions: serial dilution, solvent evaporation and spray drying. Spray drying was the best method to obtain amorphous solid dispersions. However, under certain conditions amorphous formulations could be obtained using solvent evaporation. Melting point depression was used to calculate interaction parameters and free energy of mixing for the various drug polymer mixtures. The spray dried solid dispersions yielded a negative free energy of mixing which indicated strong drug-polymer miscibility compared to the solvent evaporation and serial dilution method. Soluplus was the best stabilizer compared to PVP and HPMC, which is probably a consequence of strong hydrogen bonding between the two CO moieties of soluplus and the drug NH moieities.

  19. Antioxidant Activity and α-Glucosidase Inhibitory Activities of the Polycondensate of Catechin with Glyoxylic Acid.

    Directory of Open Access Journals (Sweden)

    Sheng Geng

    Full Text Available In order to investigate polymeric flavonoids, the polycondensate of catechin with glyoxylic acid (PCG was prepared and its chemically antioxidant, cellular antioxidant (CAA and α-glucosidase inhibitory activities were evaluated. The DPPH and ABTS radical scavenging activities and antiproliferative effect of PCG were lower than those of catechin, while PCG had higher CAA activity than catechin. In addition, PCG had very high α-glucosidase inhibitory activities (IC50 value, 2.59 μg/mL in comparison to catechin (IC50 value, 239.27 μg/mL. Inhibition kinetics suggested that both PCG and catechin demonstrated a mixture of noncompetitive and anticompetitive inhibition. The enhanced CAA and α-glucosidase inhibitor activities of PCG could be due to catechin polymerization enhancing the binding capacity to the cellular membrane and enzymes.

  20. Radical scavenging activity of antioxidants evaluated by means of electrogenerated HO radical.

    Science.gov (United States)

    Oliveira, Raquel; Geraldo, Dulce; Bento, Fátima

    2014-11-01

    A method is proposed and tested concerning the characterization of antioxidants by means of their reaction with electrogenerated HO radicals in galvanostatic assays with simultaneous O2 evolution, using a Pt anode fairly oxidized. The consumption of a set of species with antioxidant activity, ascorbic acid (AA), caffeic acid (CA), gallic acid (GA) and trolox (T), is described by a first order kinetics. The rate of the processes is limited by the kinetics of reaction with HO radicals and by the kinetics of charge transfer. Information regarding the scavenger activity of antioxidants is obtained by the relative value of the rate constant of the reaction between antioxidants and HO radicals, k(AO,HO)/k(O2). The number of HO radicals scavenged per molecule of antioxidant is also estimated and ranged from 260 (ascorbic acid) to 500 (gallic acid). The method is applied successfully in the characterization of the scavenger activity of ascorbic acid in a green-tea based beverage.

  1. Rate constants for 1,5- and 1,6-hydrogen atom transfer reactions of mono-, di-, and tri-aryl-substituted donors, models for hydrogen atom transfers in polyunsaturated fatty acid radicals.

    Science.gov (United States)

    DeZutter, Christopher B; Horner, John H; Newcomb, Martin

    2008-03-06

    Rate constants for 1,5- and 1,6-hydrogen atom transfer reactions in models of polyunsaturated fatty acid radicals were measured via laser flash photolysis methods. Photolyses of PTOC (pyridine-2-thioneoxycarbonyl) ester derivatives of carboxylic acids gave primary alkyl radicals that reacted by 1,5-hydrogen transfer from mono-, di-, and tri-aryl-substituted positions or 1,6-hydrogen transfer from di- and tri-aryl-substituted positions to give UV-detectable products. Rate constants for reactions in acetonitrile at room temperature ranged from 1 x 10(4) to 4 x 10(6) s(-1). The activation energies for a matched pair of 1,5- and 1,6-hydrogen atom transfers giving tri-aryl-substituted radicals were approximately equal, as were the primary kinetic isotope effects, but the 1,5-hydrogen atom transfer reaction was 1 order of magnitude faster at room temperature than the 1,6-hydrogen atom transfer reaction due to a less favorable entropy of activation for the 1,6-transfer reaction. Solvent effects on the rate constants for the 1,5-hydrogen atom transfer reaction of the 2-[2-(diphenylmethyl)phenyl]ethyl radical at ambient temperature were as large as a factor of 2 with the reaction increasing in rate in lower polarity solvents. Hybrid density functional theory computations for the 1,5- and 1,6-hydrogen atom transfers of the tri-aryl-substituted donors were in qualitative agreement with the experimental results.

  2. EPR parameters of amino acid radicals in P. eryngii versatile peroxidase and its W164Y variant computed at the QM/MM level.

    Science.gov (United States)

    Bernini, Caterina; Pogni, Rebecca; Ruiz-Dueñas, Francisco J; Martínez, Angel T; Basosi, Riccardo; Sinicropi, Adalgisa

    2011-03-21

    Quantum mechanics/molecular mechanics (QM/MM) methods, employing density functional theory (DFT), have been used to compute the electron paramagnetic resonance (EPR) parameters of tryptophan and tyrosyl radical intermediates involved in the catalytic cycle of Pleurotus eryngii versatile peroxidase (VP) and its W164Y variant, respectively. These radicals have been previously experimentally detected and characterized both in the two-electron and one-electron activated forms of the enzymes. In this work, the well-studied W164 radical in VP has been chosen for calibration purposes because its spectroscopic properties have been extensively studied by multifrequency EPR and ENDOR spectroscopies. Using a B3LYP/CHARMM procedure, appropriately accounting for electrostatic, such as hydrogen bonding, and steric environmental interactions, a good agreement between the calculated and measured EPR parameters for both radicals has been achieved; g-tensors, hyperfine coupling constants (hfcc) and Mulliken spin densities have been correlated to changes in geometries, hydrogen bond networks and electrostatic environment, with the aim of understanding the influence of the protein surroundings on EPR properties. In addition, the present calculations demonstrate, for VP, the formation of a neutral tryptophan radical, hydrogen bonded to the nearby E243, via a stepwise electron and proton transfer with earlier involvement of a short-lived tryptophan cationic species. Instead, for W164Y, the QM/MM dynamics simulation shows that the tyrosine oxidation proceeds via a concerted electron and proton transfer and is accompanied by a significant reorganization of residues and water molecules surrounding the tyrosyl radical.

  3. Alterations in the Noxa/Mcl-1 axis determine sensitivity of small cell lung cancer to the BH3 mimetic ABT-737.

    Science.gov (United States)

    Hauck, Paula; Chao, Bo H; Litz, Julie; Krystal, Geoffrey W

    2009-04-01

    To understand the molecular basis for variable sensitivity to the BH3 mimetic drug ABT-737, the abundance of Bcl-2 family members was assayed in a panel of small cell lung cancer cell lines whose sensitivity varied over a 2-log range. Elevated Noxa and Bcl-2 levels directly correlated with sensitivity to ABT-737, whereas Mcl-1 levels were similar in all cell lines tested regardless of sensitivity. Transgenically enforced expression of Noxa but not Bcl-2 resulted in increased sensitivity to ABT-737 in multiple cell lines. This increase was especially pronounced in the H209 cell line in which expression of Noxa resulted in a proportionate decline in Mcl-1 expression. Although overexpression of Noxa enhanced sensitivity of the H526 and H82 cell lines to ABT-737, it did not result in altered Mcl-1 levels. Similarly, small interfering RNA-mediated knockdown of Noxa expression in the H146 cell line, which increased resistance to ABT-737, did not result in altered Mcl-1 levels. Therefore, three of four cell lines studied failed to show Noxa-mediated regulation of Mcl-1 expression. However, despite failure to regulate Mcl-1 levels, Noxa blocked binding of Bim to Mcl-1 following its release from Bcl-2 by ABT-737. Finally, we observed that a 24-hour incubation of the H526 and WBA cell lines with ABT-737 resulted in increased Noxa expression, suggesting that Noxa may play a direct role in ABT-737-mediated apoptosis. These results indicate that Noxa expression is the critical determinant of ABT-737 sensitivity and loss of Noxa-mediated regulation of Mcl-1 expression may be an important feature of small cell lung cancer biology.

  4. BAX and BAK1 are dispensable for ABT-737-induced dissociation of the BCL2-BECN1 complex and autophagy.

    Science.gov (United States)

    Pedro, Jose Manuel Bravo-San; Wei, Yongjie; Sica, Valentina; Maiuri, Maria Chiara; Zou, Zhongju; Kroemer, Guido; Levine, Beth

    2015-01-01

    Disruption of the complex of BECN1 with BCL2 or BCL2L1/BCL-XL is an essential switch that turns on cellular autophagy in response to environmental stress or treatment with BH3 peptidomimetics. Recently, it has been proposed that BCL2 and BCL2L1/BCL-XL may inhibit autophagy indirectly through a mechanism dependent on the proapoptotic BCL2 family members, BAX and BAK1. Here we report that the BH3 mimetic, ABT-737, induces autophagy in parallel with disruption of BCL2-BECN1 binding in 2 different apoptosis-deficient cell types lacking BAX and BAK1, namely in mouse embryonic fibroblasts cells and in human colon cancer HCT116 cells. We conclude that the BH3 mimetic ABT-737 induces autophagy through a BAX and BAK1-independent mechanism that likely involves disruption of BECN1 binding to antiapoptotic BCL2 family members.

  5. Improved production of poly-γ-glutamic acid by Bacillus subtilis D7 isolated from Doenjang, a Korean traditional fermented food, and its antioxidant activity.

    Science.gov (United States)

    Lee, Na-Ri; Lee, Sang-Mee; Cho, Kwang-Sik; Jeong, Seong-Yun; Hwang, Dae-Youn; Kim, Dong-Seob; Hong, Chang-Oh; Son, Hong-Joo

    2014-06-01

    The objectives of this study was to improve poly-γ-glutamic acid (γ-PGA) production by Bacillus subtilis D7 isolated from a Korean traditional fermented food and to assess its antioxidant activity for applications in the cosmetics and pharmaceutical industries. Strain D7 produced γ-PGA in the absence of L-glutamic acid, indicating L-glutamic acid-independent production. However, the addition of L-glutamic acid increased γ-PGA production. Several tricarboxylic acid cycle intermediates and amino acids could serve as the metabolic precursors for γ-PGA production, and the addition of pyruvic acid and D-glutamic acid to culture medium improved the yield of γ-PGA markedly. The maximum yield of γ-PGA obtained was 24.93 ± 0.64 g/l in improved medium, which was about 5.4-fold higher than the yield obtained in basal medium. γ-PGA was found to have 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (46.8 ± 1.5 %), hydroxyl radical scavenging activity (52.0 ± 1.8 %), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging activity (42.1 ± 1.8 %), nitric oxide scavenging activity (35.1 ± 1.3 %), reducing power (0.304 ± 0.008), and metal chelating activity (91.3 ± 3.5 %). These results indicate that γ-PGA has a potential use in the food, cosmetics, and biomedical industries for the development of novel products with radical scavenging activity. As far as we are aware, this is the first report to describe the antioxidant activityof γ-PGA produced by bacteria.

  6. Fluphenazine hydrochloride radical cation assay: A new, rapid and precise method to determine in vitro total antioxidant capacity of fruit extracts

    Institute of Scientific and Technical Information of China (English)

    Muhammad Nadeem Asghar; Qadeer Alam; Sharoon Augusten

    2012-01-01

    A new procedure based on generation and subsequent reduction of orange-colored fluphenazine hydrochloride radical (FPH·+)is presented for the screening of total antioxidant capacity (TAC) of various fruit matrices.The FPH·+ was obtained by mixing fluphenazine hydrochloride with persulfate (final concentration 2 mmol/L and 0.05 mmmol/L,respectively) in 3 mol/L H2SO4 with constant shaking for 5 min.The solution formed showed maximum absorption as 0.8 ± 0.02 at 500 nm in first-order derivative spectrum.The percent inhibition of the solution increased linearly on addition of increasing mounts of standard antioxidants i.e.,ascorbic acid etc.The TACs of sample citrus juices were calculated in terms of ascorbic acid equivalents (AAEs) by comparing their inhibition curves with that of ascorbic acid.Comparison of AAE values of different commercial orange juices using the newly developed FPH·+ assay and the well-known ABTS/K2S2O8 and DMPD/FeCl3 assays indicated the precision and comparable sensitivity of the method.The proposed procedure is quick,economical,and more precise and gives results comparable to contemporary assays.

  7. In vitro antioxidant potential and deoxyribonucleic acid protecting activity of CNB-001, a novel pyrazole derivative of curcumin

    Directory of Open Access Journals (Sweden)

    Richard L Jayaraj

    2014-01-01

    Full Text Available Background: Free radicals are underpinned to initiate cascade of toxic events leading to oxidative stress and resultant cell death in many neurodegenerative disorders. Now-a-days antioxidants have become mandatory in the treatment of various diseases apart from the drug′s modes of action. CNB-001, a novel hybrid molecule synthesized by combining curcumin and cyclohexyl bisphenol A is known to possess various biological activities, but the antioxidative property of the compound has not yet been elucidated. Aim: The present study is aimed to analyze various free radicals scavenging by employing in vitro antioxidant assays and to evaluate the deoxyribonucleic acid (DNA protecting the ability of CNB-001 against hydroxyl radicals. Materials and methods: The in vitro antioxidant potential of CNB-001 was evaluated by analyzing its ability to scavenge DPPH, ABTS, nitric oxide, superoxide, hydrogen peroxide, superoxide anion, hydroxyl, hydrogen peroxide radicals and reducing power using spectroscopic method. The DNA protecting activity of CNB-001 was also evaluated on pUC19 plasmid DNA subjected to hydroxyl radicals using standard agarose gel electrophoresis. Results: From the assays, it was observed that CNB-001 scavenged free radicals effectively in a dose dependent manner. CNB-001 scavenged 2,2-diphenyl-1-picrylhydrazyl (IC50 = 44.99 μg/ml, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (IC50 = 17.99 μg/ml, nitric oxide (IC50 = 1.36 μg/ml, superoxide radical (IC50 = 77.17 μg/ml, hydrogen peroxide (IC50 = 492.7 μg/ml, superoxide (IC50 = 36.92 μg/ml and hydroxyl (IC50 = 456.5 μg/ml radicals effectively and the reducing power was found to be 11.53 μg/ml. CNB-001 showed considerable protecting activity against plasmid DNA (pUC19 strand scission by ·OH at dose dependent manner. Conclusion: Results from these assays concluded that CNB-001 has a good antioxidant potential by reducing reactive oxygen and reactive nitrogen radicals and it

  8. A radical approach to radical innovation

    OpenAIRE

    Deichmann, Dirk; van der Ende, Jan

    2014-01-01

    textabstractInnovation pays. Amazon, Apple, Facebook, Google – nearly every one of today’s most successful companies has a talent for developing radical new ideas. But how best to encourage radical initiative taking from employees, and does their previous success or failure at it play a role?

  9. 植酸和几种抗氧化物质对自由基清除能力的比较%A comparative study of roles of phytic acid and several antioxidants in eradication of free radicals

    Institute of Scientific and Technical Information of China (English)

    贾炎; 涂书新; 唐世荣

    2011-01-01

    Diphenylpicrylhydrazyl (DPPH) spectrocolorimetery method was used to evaluate the an-ti-oxidative capacity of phytic acid,ascorbic acid (ASA),glutathione (GSH) and vegetable extracts. The results showed that eradication of free radical of phytic acid, ASA and GSH was pH dependent. The IC50 a value describing the ability of DPPH free radical scavenging,was 1. 94×10-2(pH = 2. 0),0. 26 (pH=4. 6) and 1. 86 (pH=5. 7) for phytic acid,GSH and ASA, respectively. In addition,adding phytic acid enhanced the eradicating ability of free radical of vegetable extracts. The results suggested that phytic acid would be an important antioxidant in plants due to its high content in plants,and pose a crucial role in resistance to oxidative stress.%在离体条件下,比较研究了植酸和几种常见的抗氧化物质(抗坏血酸、谷胱甘肽)以及部分蔬菜(青椒、黄瓜、番茄、洋葱)提取物对二苯代苦味酰基(DPPH)自由基的清除作用.结果表明:体系的pH值是影响抗氧化物质自由基清除能力的重要因子;在一定的pH值条件下,植酸表现出清除DPPH自由基的能力,其IC50值为1.94×10-2 (pH 2.0),而谷胱甘肽和抗坏血酸的IC50值分别为0.26(pH 4.6)和1.86(pH 5.7).试验表明,蔬菜提取液添加植酸后的自由基清除能力明显提高.

  10. Identification of predictive factors of response to the BH3-mimetic molecule ABT-737: an ex vivo experiment in human serous ovarian carcinoma.

    Science.gov (United States)

    Lheureux, Stéphanie; N'Diaye, Monique; Blanc-Fournier, Cécile; Dugué, Audrey Emmanuelle; Clarisse, Bénédicte; Dutoit, Soizic; Giffard, Florence; Abeilard, Edwige; Briand, Mélanie; Labiche, Alexandre; Grellard, Jean-Michel; Crouet, Hubert; Martin, Sandrine; Joly, Florence; Poulain, Laurent

    2015-03-01

    Ovarian cancers are addicted to Bcl-xL and Mcl-1, antiapoptotic members of the Bcl-2 family. Bcl-xL can be inhibited by the BH3-mimetic ABT-737. In vitro, ABT-737 can induce apoptosis of cancer cells, and its activity is potentiated by Mcl-1 inactivation. Herein, we assessed the sensitivity of human ovarian tumor nodes to ABT-737 when combined with carboplatin, which can indirectly inhibit Mcl-1. Fresh samples from 25 patients with high-grade serous ovarian cancer (HGSOC) who were chemo-naïve and had undergone surgery were prospectively exposed ex vivo to ABT-737 ± carboplatin. The treatment effect was studied on sliced tumor nodes by assessment of cleaved-caspase 3 immunostaining. We also studied the association between baseline Bcl-2 family protein expression (via immunohistochemistry) and the response of nodes to treatment. ABT-737 induced apoptosis as a single agent but its efficacy was not improved by the addition of carboplatin. Bim was frequently expressed (20/25) and its absence or low expression was associated with the absence of response to ABT-737, p value = 0.019 by Fisher's test and sensitivity = 93%, (95% confidence interval, 66-100). Moreover, we observed that in tumors in which Bim was expressed, a low expression of phospho-Erk1/2 or Mcl-1 improved the proportion of responses. This pilot study showed that ABT-737 has promise as monotherapy for HGSOC in a specific subgroup of tumors. Bim, Mcl-1, and phospho-Erk1/2 appeared to be relevant biomarkers that could be used for the selection of patients in the design of clinical trials using Navitoclax (an orally available compound related to ABT-737).

  11. Chemotherapeutic drugs sensitize human renal cell carcinoma cells to ABT-737 by a mechanism involving the Noxa-dependent inactivation of Mcl-1 or A1

    Directory of Open Access Journals (Sweden)

    Zantl Niko

    2010-06-01

    Full Text Available Abstract Background Human renal cell carcinoma (RCC is very resistant to chemotherapy. ABT-737 is a novel inhibitor of anti-apoptotic proteins of the Bcl-2 family that has shown promise in various preclinical tumour models. Results We here report a strong over-additive pro-apoptotic effect of ABT-737 and etoposide, vinblastine or paclitaxel but not 5-fluorouracil in cell lines from human RCC. ABT-737 showed very little activity as a single agent but killed RCC cells potently when anti-apoptotic Mcl-1 or, unexpectedly, A1 was targeted by RNAi. This potent augmentation required endogenous Noxa protein since RNAi directed against Noxa but not against Bim or Puma reduced apoptosis induction by the combination of ABT-737 and etoposide or vinblastine. At the level of mitochondria, etoposide-treatment had a similar sensitizing activity and allowed for ABT-737-induced release of cytochrome c. Conclusions Chemotherapeutic drugs can overcome protection afforded by Mcl-1 and A1 through endogenous Noxa protein in RCC cells, and the combination of such drugs with ABT-737 may be a promising strategy in RCC. Strikingly, A1 emerged in RCC cell lines as a protein of similar importance as the well-established Mcl-1 in protection against apoptosis in these cells.

  12. Improving the antioxidant properties of quinoa flour through fermentation with selected autochthonous lactic acid bacteria.

    Science.gov (United States)

    Rizzello, Carlo Giuseppe; Lorusso, Anna; Russo, Vito; Pinto, Daniela; Marzani, Barbara; Gobbetti, Marco

    2017-01-16

    Lactic acid bacteria strains, previously isolated from the same matrix, were used to ferment quinoa flour aiming at exploiting the antioxidant potential. As in vitro determined on DPPH and ABTS radicals, the scavenging activity of water/salt-soluble extracts (WSE) from fermented doughs was significantly (Pquinoa dough fermented with Lactobacillus plantarum T0A10. The corresponding WSE was subjected to Reverse Phase Fast Protein Liquid Chromatography, and 32 fractions were collected and subjected to in vitro assays. The most active fraction was resistant to further hydrolysis by digestive enzymes. Five peptides, having sizes from 5 to 9 amino acid residues, were identified by nano-Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra. The sequences shared compositional features which are typical of antioxidant peptides. As shown by determining cell viability and radical scavenging activity (MTT and DCFH-DA assays, respectively), the purified fraction showed antioxidant activity on human keratinocytes NCTC 2544 artificially subjected to oxidative stress. This study demonstrated the capacity of autochthonous lactic acid bacteria to release peptides with antioxidant activity through proteolysis of native quinoa proteins. Fermentation of the quinoa flour with a selected starter might be considered suitable for novel applications as functional food ingredient, dietary supplement or pharmaceutical preparations.

  13. Mathematical Evaluation of the Amino Acid and Polyphenol Content and Antioxidant Activities of Fruits from Different Apricot Cultivars

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2011-09-01

    Full Text Available Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L. cultivated in Lednice (climatic area T4, South Moravia, Czech Republic. Almost all previously published studies have focused only on analysis of certain parameters. However, we focused on detection both primary and secondary metabolites in a selection of apricot cultivars with respect to their biological activity. The contents of thirteen biogenic alpha-L-amino acids (arginine, asparagine, isoleucine, lysine, serine, threonine, valine, leucine, phenylalanine, tryptophan, tyrosine, proline and alanine were determined using ion exchange chromatography with UV-Vis spectrometry detection. Profile of polyphenols, measured as content of ten polyphenols with significant antioxidant properties (gallic acid, procatechinic acid, p-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferrulic acid and quercetrin, was determined by high performance liquid chromatography with spectrometric/electrochemical detection. Moreover, content of total phenolics was determined spectrophotometrically using the Folin-Ciocalteu method. Antioxidant activity was determined using five independent spectrophotometric methods: DPPH assay, DMPD method, ABTS method, FRAP and Free Radicals methods. Considering the complexity of the obtained data, they were processed and correlated using bioinformatics techniques (cluster analysis, principal component analysis. The studied apricot cultivars were clustered according to their common biochemical properties, which has not been done before. The observed similarities and differences were discussed.

  14. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  15. Experimental Study on Removal Sulfuric Acid Radical (Ion) from Beryllium Hydroxide%氢氧化铍中硫酸根去除试验研究

    Institute of Scientific and Technical Information of China (English)

    李中; 王清良; 李乾; 胡鄂明; 熊骁; 肖吉昌; 成泉辉

    2014-01-01

    分别采用洗涤法、氯化钡沉淀法、氢氧化钠水解再沉淀法去除氢氧化铍中硫酸根,结果表明:采用洗涤法去除硫酸根的效果最差,硫酸根去除率仅为50%;氯化钡沉淀法去除硫酸根的效果较明显,能将氢氧化铍中硫酸根含量降至0.3%以下,但氯化钡沉淀法成本较高、可能带来二次污染;氢氧化钠水解后再沉淀法能将氢氧化铍中的硫酸根含量从6.77%降到0.020%以下,硫酸根去除率达99.7%,此法具有相对成本低、无二次污染等优点,为核纯级氢氧化铍的制备提供了依据。%Tests on removal of sulfate radical contained in beryllium hydroxide were conducted with several different methods, including washing, barium chloride precipitation and a combined method of hydrolysis by sodium hydroxide and precipitation. Results indicated that washing method had the worst effect, resulting in only 50% sulfate radical removed. And the method of barium chloride precipitation brought the content of sulfate radical in beryllium hydroxide remarkably reduced to less than 0.3%, which, however, was put at a disadvantage by its high cost and possibly accompanied pollution problem. By comparison, the third method of hydrolysis by sodium hydroxide followed by precipitation could reduce the content of sulfate radical from 6.77%to less than 0.020%, with removal rate up to 99.7%. Furthermore, this method being characterized by low cost and free of secondary pollution, may be of reference for preparation of beryllium hydroxide of nuclear grade purity.

  16. Pyrimidine nucleobase radical reactivity in DNA and RNA

    Science.gov (United States)

    Greenberg, Marc M.

    2016-11-01

    Nucleobase radicals are major products of the reactions between nucleic acids and hydroxyl radical, which is produced via the indirect effect of ionizing radiation. The nucleobase radicals also result from hydration of cation radicals that are produced via the direct effect of ionizing radiation. The role that nucleobase radicals play in strand scission has been investigated indirectly using ionizing radiation to generate them. More recently, the reactivity of nucleobase radicals resulting from formal hydrogen atom or hydroxyl radical addition to pyrimidines has been studied by independently generating the reactive intermediates via UV-photolysis of synthetic precursors. This approach has provided control over where the reactive intermediates are produced within biopolymers and facilitated studying their reactivity. The contributions to our understanding of pyrimidine nucleobase radical reactivity by this approach are summarized.

  17. The Thrombospondin-1 Mimetic ABT-510 Increases the Uptake and Effectiveness of Cisplatin and Paclitaxel in a Mouse Model of Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Nicole E. Campbell

    2010-03-01

    Full Text Available Epithelial ovarian cancer (EOC comprises approximately 90% of ovarian cancers and arises from the surface epithelium. Typical treatment of EOC involves cytoreductive surgery combined with chemotherapy. More recent therapies have targeted the tumor vasculature using antiangiogenic compounds such as thrombospondin-1 (TSP-1. TSP-1 mimetic peptides such as ABT-510 have been created and have been in various clinical trials. We have previously shown that ABT-510 reduces abnormal vasculature associated with tumor tissue and increases the presence of mature blood vessels. It has been hypothesized that treatment with antiangiogenic compounds would allow increased delivery of cytotoxic agents and enhance treatment. In this study, we evaluated the potential role of ABT-510 and various chemotherapeutics (cisplatin and paclitaxel on tumor progression, angiogenesis, and the benefits of combinational treatments on tissue uptake and perfusion using an orthotopic syngeneic mouse model of EOC. Animals were treated with ABT-510 (100 mg/kg per day alone or in combination with cisplatin (2 mg/kg per 3 days or paclitaxel (10 mg/kg per 2 days at 60 days after tumor induction. Radiolabeled and fluorescently labeled paclitaxel demonstrated a significant increase in tumor uptake after ABT-510 treatment. Combined treatment with ABT-510 and cisplatin or paclitaxel resulted in a significant increase in tumor cell and tumor endothelial cell apoptosis and a resultant decrease in ovarian tumor size. Combined treatment also regressed secondary lesions and eliminated the presence of abdominal ascites. The results from this study show that through vessel normalization, ABT-510 increases uptake of chemotherapy drugs and can induce regression of advanced ovarian cancer.

  18. BMX acts downstream of PI3K to promote colorectal cancer cell survival and pathway inhibition sensitizes to the BH3 mimetic ABT-737.

    Science.gov (United States)

    Potter, Danielle S; Kelly, Paul; Denneny, Olive; Juvin, Veronique; Stephens, Len R; Dive, Caroline; Morrow, Christopher J

    2014-02-01

    Evasion of apoptosis is a hallmark of cancer, and reversing this process by inhibition of survival signaling pathways is a potential therapeutic strategy. Phosphoinositide 3-kinase (PI3K) signaling can promote cell survival and is upregulated in solid tumor types, including colorectal cancer (CRC), although these effects are context dependent. The role of PI3K in tumorigenesis combined with their amenability to specific inhibition makes them attractive drug targets. However, we observed that inhibition of PI3K in HCT116, DLD-1, and SW620 CRC cells did not induce apoptotic cell death. Moreover, these cells were relatively resistant to the Bcl-2 homology domain 3 (BH3) mimetic ABT-737, which directly targets the Bcl-2 family of apoptosis regulators. To test the hypothesis that PI3K inhibition lowers the apoptotic threshold without causing apoptosis per se, PI3K inhibitors were combined with ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis by 2.3- to 4.5-fold and reduced expression levels of MCL-1, the resistance biomarker for ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis a further 1.4- to 2.4-fold in CRC cells with small interfering RNA-depleted MCL-1, indicative of additional sensitizing mechanisms. The observation that ABT-737-induced apoptosis was unaffected by inhibition of PI3K downstream effectors AKT and mTOR, implicated a novel PI3K-dependant pathway. To elucidate this, an RNA interference (RNAi) screen of potential downstream effectors of PI3K signaling was conducted, which demonstrated that knockdown of the TEC kinase BMX sensitized to ABT-737. This suggests that BMX is an antiapoptotic downstream effector of PI3K, independent of AKT.

  19. BMX Acts Downstream of PI3K to Promote Colorectal Cancer Cell Survival and Pathway Inhibition Sensitizes to the BH3 Mimetic ABT-737

    Directory of Open Access Journals (Sweden)

    Danielle S. Potter

    2014-02-01

    Full Text Available Evasion of apoptosis is a hallmark of cancer, and reversing this process by inhibition of survival signaling pathways is a potential therapeutic strategy. Phosphoinositide 3-kinase (PI3K signaling can promote cell survival and is upregulated in solid tumor types, including colorectal cancer (CRC, although these effects are context dependent. The role of PI3K in tumorigenesis combined with their amenability to specific inhibition makes them attractive drug targets. However, we observed that inhibition of PI3K in HCT116, DLD-1, and SW620 CRC cells did not induce apoptotic cell death. Moreover, these cells were relatively resistant to the Bcl-2 homology domain 3 (BH3 mimetic ABT-737, which directly targets the Bcl-2 family of apoptosis regulators. To test the hypothesis that PI3K inhibition lowers the apoptotic threshold without causing apoptosis per se, PI3K inhibitors were combined with ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis by 2.3- to 4.5-fold and reduced expression levels of MCL-1, the resistance biomarker for ABT-737. PI3K inhibition enhanced ABT-737-induced apoptosis a further 1.4- to 2.4-fold in CRC cells with small interfering RNA-depleted MCL-1, indicative of additional sensitizing mechanisms. The observation that ABT-737-induced apoptosis was unaffected by inhibition of PI3K downstream effectors AKT and mTOR, implicated a novel PI3K-dependant pathway. To elucidate this, an RNA interference (RNAi screen of potential downstream effectors of PI3K signaling was conducted, which demonstrated that knockdown of the TEC kinase BMX sensitized to ABT-737. This suggests that BMX is an antiapoptotic downstream effector of PI3K, independent of AKT.

  20. The combination of BH3-mimetic ABT-737 with the alkylating agent temozolomide induces strong synergistic killing of melanoma cells independent of p53.

    Directory of Open Access Journals (Sweden)

    Steven N Reuland

    Full Text Available Metastatic melanoma has poor prognosis and is refractory to most conventional chemotherapies. The alkylating agent temozolomide (TMZ is commonly used in treating melanoma but has a disappointing response rate. Agents that can act cooperatively with TMZ and improve its efficacy are thus highly sought after. The BH3 mimetic ABT-737, which can induce apoptosis by targeting pro-survival Bcl-2 family members, has been found to enhance the efficacy of many conventional chemotherapeutic agents in multiple cancers. We found that combining TMZ and ABT-737 induced strong synergistic apoptosis in multiple human melanoma cell lines. When the drugs were used in combination in a mouse xenograft model, they drastically reduced tumor growth at concentrations where each individual drug had no significant effect. We found that TMZ treatment elevated p53 levels, and that the pro-apoptotic protein Noxa was elevated in TMZ/ABT-737 treated cells. Experiments with shRNA demonstrated that the synergistic effect of TMZ and ABT-737 was largely dependent on Noxa. Experiments with nutlin-3, a p53 inducer, demonstrated that p53 induction was sufficient for synergistic cell death with ABT-737 in a Noxa-dependent fashion. However, p53 was not necessary for TMZ/ABT-737 synergy as demonstrated by a p53-null line, indicating that TMZ and ABT-737 together induce Noxa in a p53-independent fashion. These results demonstrate that targeting anti-apoptotic Bcl-2 members is a promising method for treating metastatic melanoma, and that clinical trials with TMZ and Bcl-2 inhibitors are warranted.

  1. Contemporary Radical Prostatectomy

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2011-01-01

    Full Text Available Purpose. Patients diagnosed with clinically localized prostate cancer have more surgical treatment options than in the past. This paper focuses on the procedures' oncological or functional outcomes and perioperative morbidities of radical retropubic prostatectomy, radical perineal prostatectomy, and robotic-assisted laparoscopic radical prostatectomy. Materials and Methods. A MEDLINE/PubMed search of the literature on radical prostatectomy and other new management options was performed. Results. Compared to the open procedures, robotic-assisted radical prostatectomy has no confirmed significant difference in most literatures besides less blood loss and blood transfusion. Nerve sparing is a safe means of preserving potency on well-selected patients undergoing radical prostatectomy. Positive surgical margin rates of radical prostatectomy affect the recurrence and survival of prostate cancer. The urinary and sexual function outcomes have been vastly improved. Neoadjuvant treatment only affects the rate of positive surgical margin. Adjuvant therapy can delay and reduce the risk of recurrence and improve the survival of the high risk prostate cancer. Conclusions. For the majority of patients with organ-confined prostate cancer, radical prostatectomy remains a most effective approach. Radical perineal prostatectomy remains a viable approach for patients with morbid obesity, prior pelvic surgery, or prior pelvic radiation. Robot-assisted laparoscopic prostatectomy (RALP has become popular among surgeons but has not yet become the firmly established standard of care. Long-term data have confirmed the efficacy of radical retropubic prostatectomy with disease control rates and cancer-specific survival rates.

  2. Solvent optimization extraction of antioxidants from foxtail millet species' insoluble fibers and their free radical scavenging properties.

    Science.gov (United States)

    Bangoura, Mohamed Lamine; Nsor-Atindana, John; Ming, Zhou Hui

    2013-11-15

    In this study, water and 80% of four organic solvents were employed to optimize the extraction of antioxidants from two species of foxtail millet's insoluble fibers under the same temperature, time, and solid/solvent ratio. The results showed that the acetone was able to extract the maximum amount of antioxidants (2.32 mg/g fiber for white specie and 3.86 mg/g fiber for yellow specie) followed by methanol and propanol from both samples. The neutral and the ethanol on the other hand extracted small amount of the antioxidants from the two fiber materials. While considerable level of Total Polyphenols Content (TPC) was recorded in both the water and the organic solvents' extracts, only traces of Total Flavonoid content (TFC) were observed in water, methanol and ethanol extracts. Propanol and acetone extracts was negative to the TFC test. The potency of both white and yellow foxtail millets' insoluble fibers antioxidant extracts was investigated using five different in vitro tests. It was realized that there was a variation in their capacities to quench DPPH and ABTS(+) radicals for the time running of 0-60 min. The samples from the yellow cereal exhibited high inhibition capacity against ABTS(+). No correlation was observed between TPC and radical scavenging capacities for DPPH and ABTS(+). In general, the yellow species contained more antioxidants in comparison with the white one and this accounted for its high antioxidant activity.

  3. Radicalization and Radical Catalysis of Biomass Sugars: Insights from First-principles Studies

    Science.gov (United States)

    Yang, Gang; Zhu, Chang; Zou, Xianli; Zhou, Lijun

    2016-07-01

    Ab initio and density functional calculations are conducted to investigate the radicalization processes and radical catalysis of biomass sugars. Structural alterations due to radicalization generally focus on the radicalized sites, and radicalization affects H-bonds in D-fructofuranose more than in D-glucopyranose, potentially with outcome of new H-bonds. Performances of different functionals and basis sets are evaluated for all radicalization processes, and enthalpy changes and Gibbs free energies for these processes are presented with high accuracy, which can be referenced for subsequent experimental and theoretical studies. It shows that radicalization can be utilized for direct transformation of biomass sugars, and for each sugar, C rather than O sites are always preferred for radicalization, thus suggesting the possibility to activate C-H bonds of biomass sugars. Radical catalysis is further combined with Brønsted acids, and it clearly states that functionalization fundamentally regulates the catalytic effects of biomass sugars. In presence of explicit water molecules, functionalization significantly affects the activation barriers and reaction energies of protonation rather than dehydration steps. Tertiary butyl and phenyl groups with large steric hindrances or hydroxyl and amino groups resulting in high stabilities for protonation products drive the protonation steps to occur facilely at ambient conditions.

  4. Forgotten Radicals in Biology

    OpenAIRE

    2008-01-01

    Redox reactions play key roles in intra- and inter-cellular signaling, and in adaptative processes of tissues towards stress. Among the major free radicals with essential functions in cells are reactive oxygen species (ROS) including superoxide anion (O2 •-), hydroxyl radical (•OH) and reactive nitrogen species (RNS) such as nitric oxide (•NO). In this article, we review the forgotten and new radicals with potential relevance to cardiovascular pathophysiology. Approximately 0.3% of O2 •- pres...

  5. Structural and medium effects on the reactions of the cumyloxyl radical with intramolecular hydrogen bonded phenols. The interplay between hydrogen-bonding and acid-base interactions on the hydrogen atom transfer reactivity and selectivity.

    Science.gov (United States)

    Salamone, Michela; Amorati, Riccardo; Menichetti, Stefano; Viglianisi, Caterina; Bietti, Massimo

    2014-07-03

    A time-resolved kinetic study on the reactions of the cumyloxyl radical (CumO(•)) with intramolecularly hydrogen bonded 2-(1-piperidinylmethyl)phenol (1) and 4-methoxy-2-(1-piperidinylmethyl)phenol (2) and with 4-methoxy-3-(1-piperidinylmethyl)phenol (3) has been carried out. In acetonitrile, intramolecular hydrogen bonding protects the phenolic O-H of 1 and 2 from attack by CumO(•) and hydrogen atom transfer (HAT) exclusively occurs from the C-H bonds that are α to the piperidine nitrogen (α-C-H bonds). With 3 HAT from both the phenolic O-H and the α-C-H bonds is observed. In the presence of TFA or Mg(ClO4)2, protonation or Mg(2+) complexation of the piperidine nitrogen removes the intramolecular hydrogen bond in 1 and 2 and strongly deactivates the α-C-H bonds of the three substrates. Under these conditions, HAT to CumO(•) exclusively occurs from the phenolic O-H group of 1-3. These results clearly show that in these systems the interplay between intramolecular hydrogen bonding and Brønsted and Lewis acid-base interactions can drastically influence both the HAT reactivity and selectivity. The possible implications of these findings are discussed in the framework of the important role played by tyrosyl radicals in biological systems.

  6. Derivation of hydroperoxyl radical (HO2) levels at an urban site via measurement of pernitric acid (HO2NO2) by iodide chemical ionization mass spectrometry (I(-)-CIMS).

    Science.gov (United States)

    Chen, Dexian; Huey, L Gregory; Tanner, David J; Li, Jianfeng; Ng, Nga Lee; Wang, Yuhang

    2017-02-17

    Hydroperoxyl radical (HO2) is a key species to atmospheric chemistry. At warm temperatures, the hydroperoxyl radical (HO2) and NO2 come to a rapid steady state with pernitric acid (HO2NO2). This paper presents the derivation of HO2 from observations of HO2NO2 and NO2 in metropolitan Atlanta, US in winter 2014 and summer 2015. HO2 was observed to have a diurnal cycle with morning concentrations suppressed by high NO from the traffic. At night, derived HO2 levels were nonzero and exhibited correlations with O3 and NO3, consistent with previous studies that ozonolysis and oxidation by NO3 are sources of nighttime HO2. Measured and model calculated HO2 were in reasonable agreement: Without the constraint of measured HO2NO2 , the model reproduced HO2 with a model-to-observed ratio (M/O) 1.27 (r = 0.54) for winter, 2014, and 0.70 (r = 0.80) for summer, 2015. Adding measured HO2NO2 as a constraint, the model predicted HO2 with M/O = 1.13 ((r = 0.77) for winter 2014, and 0.90 ((r = 0.97) for summer 2015. These results demonstrate the feasibility of deriving HO2 from HO2NO2 measurements in warm regions where HO2NO2 has a short lifetime.

  7. One-electron oxidation of 2-(4-methoxyphenyl)-2-methylpropanoic and 1-(4-methoxyphenyl)cyclopropanecarboxylic acids in aqueous solution. the involvement of radical cations and the influence of structural effects and pH on the side-chain fragmentation reactivity.

    Science.gov (United States)

    Bietti, Massimo; Capone, Alberto

    2008-01-18

    A product and time-resolved kinetic study on the one-electron oxidation of 2-(4-methoxyphenyl)-2-methylpropanoic acid (2), 1-(4-methoxyphenyl)cyclopropanecarboxylic acid (3), and of the corresponding methyl esters (substrates 4 and 5, respectively) has been carried out in aqueous solution. With 2, no direct evidence for the formation of an intermediate radical cation 2*+ but only of the decarboxylated 4-methoxycumyl radical has been obtained, indicating either that 2*+ is not formed or that its decarboxylation is too fast to allow detection under the experimental conditions employed (k > 1 x 10(7) s(-1)). With 3, oxidation leads to the formation of the corresponding radical cation 3*+ or radical zwitterion -3*+ depending on pH. At pH 1.0 and 6.7, 3*+ and -3*+ have been observed to undergo decarboxylation as the exclusive side-chain fragmentation pathway with rate constants k = 4.6 x 10(3) and 2.3 x 10(4) s(-1), respectively. With methyl esters 4 and 5, direct evidence for the formation of the corresponding radical cations 4*+ and 5*+ has been obtained. Both radical cations have been observed to display a very low reactivity and an upper limit for their decay rate constants has been determined as k or=10, with the latter process that becomes the major fragmentation pathway around pH 12.

  8. In Vitro Antioxidant Activities, Free Radical Scavenging Capacity, and Tyrosinase Inhibitory of Flavonoid Compounds and Ferulic Acid from Spiranthes sinensis (Pers.) Ames

    OpenAIRE

    2014-01-01

    In this study, ultrasound-assisted extraction (UAE) and other methods of extracting flavonoid compounds and ferulic acid (FA) from S. sinensis were investigated. Five different extraction methods, including water extraction (W), water extraction using UAE (W+U), 75% ethanol extraction (E), 75% ethanol extraction using UAE (E+U), and supercritical CO2 extraction (SFE) were applied in the extraction of bioactive compounds (flavonoids and ferulic acid) in order to compare their efficiency. The h...

  9. Radical Scavenging Effects of Different Veronica species

    Directory of Open Access Journals (Sweden)

    Ummuhan Şebnem Harput

    2011-01-01

    Full Text Available It is well known that the excessive production of reactive oxygen species is hazardous for living organisms and damages major cellular constituents such as DNA, lipid and protein. To find new products reducing free radical damage is very important researches in recent pharmaceutical investigations. Considering this information, fourteen Veronica species are decided to research in the view point of their antioxidant capacity and the chemical content. Water extracts of the plants were tested for their radical scavenging activity against 2,2-diphenyl-1-picryl hydrazyl (DPPH, superoxide (SO and nitric oxide (NO radicals spectroscopically. Dose dependent radical scavenging activity was observed and the results were found to be comparable to that of ascorbic acid, quercetin and BHA which are known antioxidative compounds. In addition, gallic acid equivalent total phenolic contents of the plants were also determined using Folin-Ciocalteau reagent. The most significant scavenging activity was found for V. chamaedrys against SO radical (IC50 113.40 μg/ml and V. officinalis against DPPH and NO radicals (IC50 40.93 μg/ml, 570.33 μg/ml, respectively .

  10. Optimization of ultrasonic-assisted extraction and radical-scavenging capacity of phenols and flavonoids from Clerodendrum cyrtophyllum Turcz leaves.

    Directory of Open Access Journals (Sweden)

    Jing Zhou

    Full Text Available Ultrasonic-assisted extraction (UAE was developed to extract phenolic and flavonoid antioxidants from Clerodendrum cyrtophyllum Turcz leaves. The optimal experimental parameters for antioxidant extraction from C. cyrtophyllum leaves were measured using single-factor experimentation combined with response surface methodology (RSM. Total phenolic content (TPC and total flavonoid content (TFC assays were used to quantify antioxidant compounds. Next, antioxidant radical scavenging capacity was measured using 2,2'-diphenyl-1-picrylhydrazyl (DPPH and 2,2' -azino-bis(3-ethylbenzothiazoline-6-sulphonicacid (ABTS radicals. Optimized extraction conditions for UAE from C. cyrtophyllum leaves were as follows: 60.9% ethanol, 85.4 min, and 63.3°C for maximal TPC extraction (16.8 ± 0.2 mg GAE/g DW; 67.7% ethanol, 82.9 min, and 63.0 °C for maximal TFC extraction (49.3 ± 0.4 mg RT/g DW; 48.8% ethanol, 85.1 min, and 63.9 °C for maximal DPPH radical-scavenging capacity (86.8 ± 0.2%; and 50.6% ethanol, 81.3 min, and 63.4 °C for maximal ABTS radical-scavenging capacity (92.9 ± 0.5%. Ethanol concentration was the most important factor in the extraction process. Our work offers optimal extraction conditions for C. cyrtophyllum as a potential source of natural antioxidants.

  11. Optimization of ultrasonic-assisted extraction and radical-scavenging capacity of phenols and flavonoids from Clerodendrum cyrtophyllum Turcz leaves.

    Science.gov (United States)

    Zhou, Jing; Zheng, Xiaoxue; Yang, Qi; Liang, Zhenyi; Li, Donghai; Yang, Xiaobo; Xu, Jing

    2013-01-01

    Ultrasonic-assisted extraction (UAE) was developed to extract phenolic and flavonoid antioxidants from Clerodendrum cyrtophyllum Turcz leaves. The optimal experimental parameters for antioxidant extraction from C. cyrtophyllum leaves were measured using single-factor experimentation combined with response surface methodology (RSM). Total phenolic content (TPC) and total flavonoid content (TFC) assays were used to quantify antioxidant compounds. Next, antioxidant radical scavenging capacity was measured using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2' -azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) radicals. Optimized extraction conditions for UAE from C. cyrtophyllum leaves were as follows: 60.9% ethanol, 85.4 min, and 63.3°C for maximal TPC extraction (16.8 ± 0.2 mg GAE/g DW); 67.7% ethanol, 82.9 min, and 63.0 °C for maximal TFC extraction (49.3 ± 0.4 mg RT/g DW); 48.8% ethanol, 85.1 min, and 63.9 °C for maximal DPPH radical-scavenging capacity (86.8 ± 0.2%); and 50.6% ethanol, 81.3 min, and 63.4 °C for maximal ABTS radical-scavenging capacity (92.9 ± 0.5%). Ethanol concentration was the most important factor in the extraction process. Our work offers optimal extraction conditions for C. cyrtophyllum as a potential source of natural antioxidants.

  12. Orgasm after radical prostatectomy

    NARCIS (Netherlands)

    Koeman, M; VanDriel, MF; Schultz, WCMW; Mensink, HJA

    1996-01-01

    Objective To evaluate the ability to obtain and the quality of orgasm after radical prostatectomy, Patients and methods The orgasms experienced after undergoing radical prostatectomy were evaluated in 20 men (median age 65 years, range 56-76) using a semi-structured interview and a self-administered

  13. The Radicalization Puzzle [video

    OpenAIRE

    Mohammed Hafez; Center for Homeland Defense and Security Naval Postgraduate School

    2015-01-01

    This 20 minute lecture, by Dr. Mohammad Hafez of the Naval Postgraduate School examines the driving factors behind the process of radicalization, turning seemingly ordinary men and women into potential terrorists. The lecture is based on the article "The Radicalization Puzzle: A Theoretical Synthesis of Empirical Approaches to Homegrown Extremism" in Studies in Conflict and Terrorism, by Mohammad Hafez and Creighton Mullins.

  14. Characterization of polyphenolic constituents and radical scavenging ability of ripe tomato and red pepper fruits

    OpenAIRE

    Akomolafe, Seun F.; Ganiyu Oboh

    2015-01-01

    Objective: Characterization of polyphenolic contents and the inhibitory effects of aqueous extracts of ripe tomato (Lycopersicon esculentum) and red pepper (Capsicum annuum) fruits on the sodium nitroprusside (SNP) and iron(II) (Fe2+)-induced lipid peroxidation in rat liver were examined in this study. Methods: Various experimental models such as the ABTS and #8226; (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) scavenging ability and ferric reducing power were used to character...

  15. A randomized, double-blind, placebo-controlled phase 2 study of α4β2 agonist ABT-894 in adults with ADHD.

    Science.gov (United States)

    Bain, Earle E; Robieson, Weining; Pritchett, Yili; Garimella, Tushar; Abi-Saab, Walid; Apostol, George; McGough, James J; Saltarelli, Mario D

    2013-02-01

    Dysregulation of the neuronal nicotinic acetylcholine receptor (NNR) system has been implicated in attention-deficit/hyperactivity disorder (ADHD), and nicotinic agonists improve attention across preclinical species and humans. Hence, a randomized, double-blind, placebo-controlled, crossover study was designed to determine the safety and efficacy of a novel α4β2 NNR agonist (ABT-894 (3-(5,6-dichloro-pyridin-3-yl)-1(S),5 (S)-3,6-diazabicyclo[3.2.0]heptane)) in adults with ADHD. Participants (N=243) were randomized to one of four dose regimens of ABT-894 (1, 2, and 4 mg once daily (QD)) or 4 mg twice daily (BID) or the active comparator atomoxetine (40 mg BID) vs placebo for 28 days. Following a 2-week washout period, participants crossed over to the alternative treatment condition (active or placebo) for an additional 28 days. Primary efficacy was based on an investigator-rated Conners' Adult ADHD Rating Scale (CAARS:Inv) Total score at the end of each 4-week treatment period. Additional secondary outcome measures were assessed. A total of 238 patients were assessed for safety end points, 236 patients were included in the intent-to-treat data set, and 196 were included in the completers data set, which was the prespecified, primary data set for efficacy. Both the 4 mg BID ABT-894 and atomoxetine groups demonstrated significant improvement on the primary outcome compared with placebo. Several secondary outcome measures were also significantly improved with 4 mg BID ABT-894. Overall, ABT-894 was well tolerated at all dose levels. These results provide initial proof of concept for the use of α4β2 agonists in the treatment of adults with ADHD. Further investigation of ABT-894, including higher doses, is therefore warranted.

  16. MO-DE-304-01: The Abt Study of Medical Physicist Work Values for Radiation Oncology Physics Services: Round IV

    Energy Technology Data Exchange (ETDEWEB)

    Mills, M. [James Graham Brown Cancer Center (United States)

    2015-06-15

    The Abt study of medical physicist work values for radiation oncology physics services, Round IV is completed. It supersedes the Abt III study of 2008. The 2015 Abt study measured qualified medical physicist (QMP) work associated with routine radiation oncology procedures as well as some special procedures. As before, a work model was created to allow the medical physicist to defend QMP work based on both routine and special procedures service mix. The work model can be used to develop a cost justification report for setting charges for radiation oncology physics services. The Abt study Round IV was designed to empower the medical physicist to negotiate a service or employment contract with providers based on measured national QMP workforce and staffing data. For a variety of reasons, the diagnostic imaging contingent of AAPM has had a more difficult time trying estimate workforce requirements than their therapy counterparts. Over the past several years, the Diagnostic Work and Workforce Study Subcommittee (DWWSS) has collected survey data from AAPM members, but the data have been very difficult to interpret. The DWWSS has reached out to include more AAPM volunteers to create a more full and accurate representation of actual clinical practice models on the subcommittee. Though much work remains, through hours of discussion and brainstorming, the DWWSS has somewhat of a clear path forward. This talk will provide attendees with an update on the efforts of the subcommittee. Learning Objectives: Understand the new information documented in the Abt studies. Understand how to use the Abt studies to justify medical physicist staffing. Learn relevant historical information on imaging physicist workforce. Understand the process of the DWWSS in 2014. Understand the intended path forward for the DWWSS.

  17. 联合甲磺酸伊马替尼和ABT-737对胃肠间质瘤细胞凋亡的影响%Influence of imatinib combined with ABT-737 on apoptosis of gastrointestinal stromal tumor cells

    Institute of Scientific and Technical Information of China (English)

    杨振; 乔师师; 党晓卫

    2011-01-01

    Objective To observe the effect of imatinib (IM) combined with ABT-737 on apoptosis of gastrointestinal stromal tumor cells.Methods We treated the GIST-882 with ABT-737 alone or ABT737 combined with imatinib.The effect of different concentrations of ABT-737 at different time points on the cell viability was determined by methyl thiazol tetrazolium (MTT).The expression of bcl-2 in GIST882 after IM treatment alone was analyzed by Western blotting.The activation form of Caspase-3 after IM or ABT-737 treatment alone and combination of IM with ABT-737 was analyzed by Western blotting.The effect of combination of IM with ABT-737 on the cell viability was determined by MTT.Results After treatment of GIST-882 cells with ABT-737 alone at a concentration of 10 μmol/L,the 24-,48- and 72-h survival rate of tumor cells was respectively 70%,55% and 38%.At the concentration of 20 μmol/LABT-737,the 24-,48- and 72-h survival rate was less than 20%.After treatment with IM at a concentration of 0.1 μmol/L combined with ABT-737 at a concentration of 0.1 μmol/L,the survival rate of GIST-882 cells was less than 20%.The combined use of IM with ABT-737 both at the concentration of 10 μmol/L could reduce the survival rate of GIST-882 cells to < 10%.IM treatment alone did not have any effect on the expression of bcl-2.The activation form of Caspase-3 was upregulated by the treatment of combination of IM with ABT-737.Different concentrations of IM combined with ABT-737 could decline the cells viability.Conclusion Combination of ABT-737 with IM could enhance the cell apoptosis.%目的 观察联合甲磺酸伊马替尼(IM)和ABT-737对胃肠间质瘤细胞凋亡的影响.方法 培养胃肠间质瘤细胞株GIST-882;噻唑蓝(MTT)比色法分析不同浓度ABT-737和不同处理时间对GIST-882细胞生长的影响;分析联合应用不同浓度IM和ABT-737对GIST882细胞生长的影响.Western blot法分析IM处理对bcl-2蛋白的影响;并分析联合应用IM和ABT

  18. Free radical scavenging activity of leaves of Cucumis sativus

    OpenAIRE

    Pritesh Rashmikant Shah; Swati Dhande; Yadunath Joshi; Vilasrao Kadam

    2013-01-01

    Cucumis sativus commonly called as ‘Cucumber’ is commonly used plant throughout the world. The plant is attributed to various uses in Ayurveda. The methanolic extract of leaves of Cucumis sativus was screened for free radical scavenging activity properties using gallic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) free radical. Different concentrations of leaf extract ranging from 100- 1000µg/ml were subjected to DPPH...

  19. Glutathione-induced radical formation on lactoperoxidase does not correlate with the enzyme's peroxidase activity.

    Science.gov (United States)

    Bonini, Marcelo G; Siraki, Arno G; Bhattacharjee, Suchandra; Mason, Ronald P

    2007-04-01

    Lactoperoxidase (LPO) is believed to serve as a mediator of host defense against invading pathogens. The protein is more abundant in body fluids such as milk, saliva, and tears. Lactoperoxidase is known to mediate the oxidation of halides and (pseudo)halides in the presence of hydrogen peroxide to reactive intermediates presumably involved in pathogen killing. More recently, LPO has been shown to oxidize a wide diversity of thiol compounds to thiyl free radicals, which ultimately lead to the formation of a protein radical characterized by DMPO-immunospin trapping. In the same study by our group the authors claimed that a consequence of this protein radical formation was the inactivation of LPO (Guo et al., J. Biol. Chem.279:13272-13283; 2004). Here we demonstrate that although thiyl radical formation does lead to LPO radical production, the formation of this radical is unrelated to the enzyme's activity. We suggest the source of this misleading interpretation to be the binding of GSH to ELISA plates, which interferes with ABTS and guaiacol oxidation. In addition, DMPO-GSH-nitrone adducts bind to ELISA plates, leading to ambiguities of interpretation since we have demonstrated that DMPO-GSH nitrone does not bind to LPO, and only LPO-protein-DMPO-nitrone adducts can be detected by Western blot.

  20. Evaluation of free radical scavenging and anti-oxidative capacity of polydatin-nanostructured lipid carriers

    Science.gov (United States)

    Meng, Xiang-Ping; Shi, Fan; Li, Hai-Jie; Yin, Li-De; Wang, Yi-Fei; Wang, Zhi-ping; Chen, Tong-sheng

    2016-10-01

    Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical (ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, polydatin loaded nanostructured lipid carriers (Pol-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Pol-NLC on free radical scavenging and anti-oxidative capacity is investigated. The particle size and zeta potential of Pol-NLC were 113.9 +/- 1.1 nm and -16.3 1 +/- 0.27 mV, respectively. By free radical scavenging assays, the IC50 value of Pol-NLC were 28.71, 9.83 μg/mL with DPPH, ABTS assay respectively, and 0.143 mg ferrous sulfate/1 mg Pol-NLC with FRAP assay. These results indicated that the antioxidant properties of Pol-NLC hold great potential used as an alternative to more toxic synthetic anti-oxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

  1. Data on the DNA damaging and mutagenic potential of the BH3-mimetics ABT-263/Navitoclax and TW-37.

    Science.gov (United States)

    Green, Maja M; Shekhar, Tanmay M; Hawkins, Christine J

    2016-03-01

    Unfortunately, the mutagenic activities of chemotherapy and radiotherapy can provoke development of therapy-induced malignancies in cancer survivors. Non-mutagenic anti-cancer therapies may be less likely to trigger subsequent malignant neoplasms. Here we present data regarding the DNA damaging and mutagenic potential of two drugs that antagonize proteins within the Bcl-2 family: ABT-263/Navitoclax and TW-37. Our data reveal that concentrations of these agents that stimulated Bax/Bak-dependent signaling provoked little DNA damage and failed to trigger mutations in surviving cells. The data supplied in this article is related to the research work entitled "Inhibition of Bcl-2 or IAP proteins does not provoke mutations in surviving cells" [1].

  2. Staining of wool using the reaction products of ABTS oxidation by laccase: synergetic effects of ultrasound and cyclic voltammetry.

    Science.gov (United States)

    Munteanu, Florentina-Daniela; Basto, Carlos; Gübitz, Georg M; Cavaco-Paulo, Artur

    2007-03-01

    The effects of ultrasound on 2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonate) enzymatic oxidation by laccase (Trametes villosa) has been studied by means of cyclic voltammetry. The reaction was allowed to proceed in the presence of a piece of wool and the coloration depth of the wool fabric was measured by means of K/S. It was observed that cyclic voltammetry is influenced the dyeing process and higher K/S values were obtained when the cyclic voltammetry was combined with the ultrasonic irradiation. Moreover, the K/S value is the sum of the values obtained when the wool staining is done in just the presence of cyclic voltammetry or in just the presence of ultrasound. The results obtained on the indigo carmine decolourization gives information on the importance of controlling the amount of ABTS(+) formed during the ultrasonication process.

  3. Oxidation of SO2 by stabilized Criegee intermediate (sCI radicals as a crucial source for atmospheric sulfuric acid concentrations

    Directory of Open Access Journals (Sweden)

    M. Boy

    2013-04-01

    Full Text Available The effect of increased reaction rates of stabilized Criegee intermediates (sCIs with SO2 to produce sulfuric acid is investigated using data from two different locations, SMEAR II, Hyytiälä, Finland, and Hohenpeissenberg, Germany. Results from MALTE, a zero-dimensional model, show that using previous values for the rate coefficients of sCI + SO2, the model underestimates gas phase H2SO4 by up to a factor of two when compared to measurements. Using the rate coefficients recently calculated by Mauldin et al. (2012 increases sulfuric acid by 30–40%. Increasing the rate coefficient for formaldehyde oxide (CH2OO with SO2 according to the values recommended by Welz et al. (2012 increases the H2SO4 yield by 3–6%. Taken together, these increases lead to the conclusion that, depending on their concentrations, the reaction of stabilized Criegee intermediates with SO2 could contribute as much as 33–46% to atmospheric sulfuric acid gas phase concentrations at ground level. Using the SMEAR II data, results from SOSA, a one-dimensional model, show that the contribution from sCI reactions to sulfuric acid production is most important in the canopy, where the concentrations of organic compounds are the highest, but can have significant effects on sulfuric acid concentrations up to 100 m. The recent findings that the reaction of sCI + SO2 is much faster than previously thought together with these results show that the inclusion of this new oxidation mechanism could be crucial in regional as well as global models.

  4. pH dependence and structural interpretation of the reactions of Coprinus cinereus peroxidase with hydrogen peroxide, ferulic acid, and 2,2'-azinobis.

    Science.gov (United States)

    Abelskov, A K; Smith, A T; Rasmussen, C B; Dunford, H B; Welinder, K G

    1997-08-01

    Steady-state and transient-state analysis of Coprinus cinereus peroxidase, CIP (identical to Arthromyces ramosus peroxidase), was used to characterize the kinetics of the three fundamental steps in heme peroxidase catalysis: compound I (cpd I) formation, cpd I reduction, and compound II (cpd II) reduction. The rate constant k1 for cpd I formation determined by transient-state analysis is (9.9 +/- 0.6) x 10(6) M-1 s-1. The k1 determined by steady-state analysis is (8.8 +/- 0.6) x 10(6) M-1 s-1 in the presence of ferulic acid and (6.7 +/- 0.2) x 10(6) M-1 s-1 in the presence of ABTS. The value of k1 is constant from pH 6 to 11. However, at low pH the value of k1 decreases, corresponding to titration of an enzyme group with a pKa of 5.0. Titration of this group is also detected from cyanide-binding kinetics. Furthermore, titration of this group is linked with marked spectroscopic changes unique to CIP. We ascribe these changes to protonation of proximal His183. A very low pKa is proposed for distal His55 in the resting state of CIP. The rate constants, k2 for cpd I and k3 for cpd II reduction, are very large for both ferulic acid and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS). For ferulic acid, transient-state kinetic analysis shows that the values of k2 and k3 are identical at pH 5-6, and the ratio k2/k3 increases to 10 at pH 10. The similar magnitude of k2 and k3 is unusual for a peroxidase. Both k2 and k3 decrease with increasing pH, and both are influenced by two ionizations: one with a pKa value near 7, assumed to reflect the protonation of His55; and the other with pKa of 9.0 +/- 0.7 for k2 and 8.8 +/- 0.4 for k3, perhaps reflecting the phenol-linked deprotonation of ferulic acid. Steady-state analysis at pH 7.0 gave k2k3/(k2 + k3) = (2.2 +/- 0.1) x 10(7) M-1 s-1 for ferulic acid, and (2.0 +/- 0.7) x 10(7) M-1 s-1 for ABTS and revealed a unimolecular step with ku = 1500 s-1, ascribed to slow ABTS radical product release. From transient

  5. Damage of Deoxyribonucleic Acid Caused by Hydroxyl Radical%羟基自由基引起的脱氧核糖核酸损伤研究

    Institute of Scientific and Technical Information of China (English)

    王晓星; 方艳芬; 杨静; 陈登霞; 黄应平; 张爱清

    2011-01-01

    以鲱鱼精脱氧核糖核酸(Herring sperm DNA)为研究对象,利用紫外光(UV,200~275 nn,66.4 Lx)激发纳米TiO2发生光催化作用介导产生羟基自由基(Hydroxyl radical,·OH),探讨·OH引发DNA氧化损伤特性.采用凝胶电泳和高效液相色谱(HPLC)分析法跟踪DNA损伤历程;应用电子自旋共振(Electron spin resonance,ESR)及分光光度法跟踪损伤过程氧化物种及H2O2相对浓度的变化;运用生物标准样8-9羟脱氧鸟苷(8-Hydroxy-2'-deoxyguanosine,8-OHdG)为内标物,通过HPLC分析DNA损伤产物,研究DNA损伤机理.结果表明,较单纯UV辐照或暗光(Dark)催化条件,DNA浓度10 mg/L,TiO2浓度1.5g/L、pH 7~8,紫外光激发纳米TiO2介导产生·OH引发DNA损伤程度最大;DNA损伤为·OH氧化历程.并伴随有深度氧化过程;DNA结构中鸟嘌吟最易氧化损伤,8-OHdG为DNA氧化损伤中间产物及鸟嘌吟氧化损伤的特异产物.%Oxidative damage characteristic of Herring Sperm DNA by hydroxyl radical ( · OH) which was excited by TiO2 under UV irradiation (200-275 nm, 66.4 Lx) was studied. The process of DNA damage was detected by gel electrophoresis and high performance liquid chromatographic analysis.Electron spin resonance (ESR) and spectrophotometry were used to determine the oxygen species and the relative concentration of H2O2 , respectively. The mechanism of DNA damage was studied using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as an internal standard. The results showed that DNA can be damaged by · OH generated from photocatalysis. Compared with UV or Dark/TiO2 system, the degree of DNA damage reached the maximum in the UV/TiO2 system under the condition of DNA concentration 10 mg/L, TiO2 concentration 1.5 g/L and pH 7-8. The damage was caused by the process of · OH oxidation of TiO2 under UV irradiation and deep mineralization of DNA took place.Guanine was easy to damage than the other groups in DNA. 8-OHdG was one intermediate product of DNA damage and a special product of

  6. Salvage robotic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Samuel D Kaffenberger

    2014-01-01

    Full Text Available Failure of non-surgical primary treatment for localized prostate cancer is a common occurrence, with rates of disease recurrence ranging from 20% to 60%. In a large proportion of patients, disease recurrence is clinically localized and therefore potentially curable. Unfortunately, due to the complex and potentially morbid nature of salvage treatment, radical salvage surgery is uncommonly performed. In an attempt to decrease the morbidity of salvage therapy without sacrificing oncologic efficacy, a number of experienced centers have utilized robotic assistance to perform minimally invasive salvage radical prostatectomy. Herein, we critically evaluate the existing literature on salvage robotic radical prostatectomy with a focus on patient selection, perioperative complications and functional and early oncologic outcomes. These results are compared with contemporary and historical open salvage radical prostatectomy series and supplemented with insights we have gained from our experience with salvage robotic radical prostatectomy. The body of evidence by which conclusions regarding the efficacy and safety of robotic salvage radical prostatectomy can be drawn comprises fewer than 200 patients with limited follow-up. Preliminary results are promising and some outcomes have been favorable when compared with contemporary open salvage prostatectomy series. Advantages of the robotic platform in the performance of salvage radical prostatectomy include decreased blood loss, short length of stay and improved visualization. Greater experience is required to confirm the long-term oncologic efficacy and functional outcomes as well as the generalizability of results achieved at experienced centers.

  7. Chemical composition, fatty acid content and antioxidant potential of meat from goats supplemented with Moringa (Moringa oleifera) leaves, sunflower cake and grass hay.

    Science.gov (United States)

    Qwele, K; Hugo, A; Oyedemi, S O; Moyo, B; Masika, P J; Muchenje, V

    2013-03-01

    The present study determined the chemical composition, fatty acid (FA) content and antioxidant capacity of meat from goats supplemented with Moringa oleifera leaves (MOL) or sunflower cake (SC) or grass hay (GH). The meat from goat supplemented with MOL had higher concentrations of total phenolic content (10.62±0.27 mg tannic acid equivalent E/g). The MOL significantly scavenged 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS) radical to 93.51±0.19% (93.51±0.19%) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical to 58.95±0.3% than other supplements. The antioxidative effect of MOL supplemented meat on catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD) and lipid oxidation (LO) was significantly (P<0.05) higher than other meat from goat feed on grass hay or those supplemented with sunflower seed cake. The present study indicated that the anti-oxidative potential of MOL may play a role in improving meat quality (chemical composition, colour and lipid stability).

  8. Impact of Altitudes and Habitats on Valerenic Acid, Total Phenolics, Flavonoids, Tannins, and Antioxidant Activity of Valeriana jatamansi.

    Science.gov (United States)

    Jugran, Arun K; Bahukhandi, Amit; Dhyani, Praveen; Bhatt, Indra D; Rawal, Ranbeer S; Nandi, Shyamal K

    2016-07-01

    The changes in total phenolics, flavonoids, tannins, valerenic acid, and antioxidant activity were assessed in 25 populations of Valeriana jatamansi sampled from 1200 to 2775 m asl and four habitat types of Uttarakhand, West Himalaya. Significant (p total phenolics, flavonoids, valerenic acid, and antioxidant activity in aerial and root portions and across the populations were observed. Antioxidant activity measured by three in vitro antioxidant assays, i.e., 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) (ABTS) radical scavenging, 2,2'-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging, and ferric-reducing antioxidant power (FRAP) assays, showed significant (p < 0.05) differences across the populations. However, no clear pattern was found in phytochemicals across the altitudinal range. Among habitat types, (pine, oak, mixed forest, and grassy land), variation in phytochemical content and antioxidant activity were observed. Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity. The results recommended that the identified populations with higher value of phytochemicals and antioxidants can be utilized for mass multiplication and breeding program to meet the domestic as well as commercial demand.

  9. Radical chemistry of artemisinin

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, Evgenii T; Solodova, S L; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2010-12-29

    The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

  10. Radical chemistry of artemisinin

    Science.gov (United States)

    Denisov, Evgenii T.; Solodova, S. L.; Denisova, Taisa G.

    2010-12-01

    The review summarizes physicochemical characteristics of the natural sesquiterpene peroxide artemisinin. The kinetic schemes of transformations of artemisinin radicals under anaerobic conditions are presented and analyzed. The sequence of radical reactions of artemisinin in the presence of oxygen is considered in detail. Special emphasis is given to the intramolecular chain oxidation resulting in the transformation of artemisinin into polyatomic hydroperoxide. The kinetic characteristics of elementary reaction steps involving alkyl, alkoxyl, and peroxyl radicals generated from artemisinin are discussed. The results of testing of artemisinin and its derivatives for the antimalarial activity and the scheme of the biochemical synthesis of artemisinin in nature are considered.

  11. Study of the manganese (II) manganese (III) complexes with quinaldic acid in aprotic medium, mononuclear and binuclear species produced under these conditions and possible formation of radical species upon oxidation or reduction of the ligand

    Energy Technology Data Exchange (ETDEWEB)

    Bodini, E.M.; Funes, M.M.; Valle, M.A. del; Arancibia, V. [Departamento de Quimica Analitica y Electroquimica, Facultad de Quimica, Universidad Catolica de Chile (Switzerland)

    1996-11-01

    The redox chemistry of the ligand Quinaldic acid (2-QA), its monoanion and its complexes with manganese (II) and manganese (III) has studied in dimethylsulphoxide using electrochemical, spectroscopic and magnetic measurements. The protonated ligand is reduce at -1.28 V vs SCE with the transfer of one equivalent of charge the resulting solution presents oxidation peaks at -0.02 V, +0.32 V and +1.14 V vs SCE which is indicative that both radical and dimeric species are involved in the oxidation processes. The combination of the monoanion of the ligand with Mn(II) in a 1:2 mole ratio forms a stable complex which presents a magnetic susceptibility of 5.90B.M. and conditional formation constant of 1.71 x 10``8 M``-2. Its oxidation at +0.76 V vs SCE yields a brown complex of Mn(III) with a magnetic susceptibility of 4.80 B.M. The voltammetric behaviour of the latter species indicates that is probably binuclear. This complex is reduced at +0.60 V vs SCE generating a Mn(II)-Mn(III) mixed-valance complex, and a second reduction at -0.40 V vs SCE regenerating the mononuclear Mn(II) complex. The mixed-valance complex decomposes quickly generating the corresponding Mn(II) and Mn(III) monomers. On the other hand, in the presence of this metal ion as counter-ion, both its +2 or +3 oxidation state, the monoanion of the ligand shows reduction processes that might lead to the stabilization of radical species. the voltammetric and spectroscopic characterization if these species is described. The results may be useful to the understanding of the charge transfer mechanism in biological systems. (Author) 26 refs.

  12. Antimicrobial, free radical scavenging activities and catalytic oxidation of benzyl alcohol by nano-silver synthesized from the leaf extract of Aristolochia indica L.: a promenade towards sustainability

    Science.gov (United States)

    Shanmugam, C.; Sivasubramanian, G.; Parthasarathi, Bera; Baskaran, K.; Balachander, R.; Parameswaran, V. R.

    2016-06-01

    Silver nanoparticles (Ag-NPs) were synthesized from aqueous silver nitrate through a simple route using the leaf extract of Aristolochia indica L. (LAIL) which acted as a reducing as well as capping agent. X-ray diffraction confirmed that the synthesized silver particles have a face centred cubic structure. EDS predicted the presence of elemental silver. The SEM images showed the synthesis of spherically mono-dispersed particles, with nano dimensions accounted by the TEM images. Infra-red spectrum adopted to the different organic functionalities present at the surface of the particles. TGA indicated an overall 11 % weight loss up to 1000 °C, suggesting desorption of biomolecules from the surface. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of metallic silver nanoparticles. The prepared material was utilized as catalyst in the oxidation of benzyl alcohol with molecular oxygen as the oxidant in methanol, under ambient conditions of temperature and pressure. Also Ag-NPs showed good to moderate anti-microbial activity employing the Agar disc diffusion method against various strains using Ciprofloxacin and Fluconazole as standard. Free radical scavenging activity of the nanoparticles were observed by modified 1,1-diphynyl-2-picrylhydrazyl, DPPH and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS in vitro assays. The work presented here demonstrates the adaptability of the synthesized Ag-NPs in participating as a disinfectant agent, free radical scavenger and an effective oxidation catalyst. The basic premise of attaining sustainability through the green synthesis of smart multifaceted materials has been consciously addressed.

  13. Radical prostatectomy - discharge

    Science.gov (United States)

    ... to 6 months. You will learn exercises (called Kegel exercises) that strengthen the muscles in your pelvis. ... Radical prostatectomy Retrograde ejaculation Urinary incontinence Patient Instructions Kegel exercises - self-care Suprapubic catheter care Urinary catheters - ...

  14. Safety and Efficacy of ABT-089 in Pediatric Attention-Deficit/Hyperactivity Disorder: Results from Two Randomized Placebo-Controlled Clinical Trials

    Science.gov (United States)

    Wilens, Timothy E.; Gault, Laura M.; Childress, Ann; Kratochvil, Christopher J.; Bensman, Lindsey; Hall, Coleen M.; Olson, Evelyn; Robieson, Weining Z.; Garimella, Tushar S.; Abi-Saab, Walid M.; Apostol, George; Saltarelli, Mario D.

    2011-01-01

    Objective: To assess the safety and efficacy of ABT-089, a novel alpha[subscript 4]beta[subscript 2] neuronal nicotinic receptor partial agonist, vs. placebo in children with attention-deficit/hyperactivity disorder (ADHD). Method: Two multicenter, randomized, double-blind, placebo-controlled, parallel-group studies of children 6 through 12 years…

  15. Setting the stage for electron transfer: Molecular basis of ABTS-binding to four laccases from Trametes versicolor at variable pH and protein oxidation state

    DEFF Research Database (Denmark)

    Christensen, Niels Johan; Kepp, Kasper Planeta

    2014-01-01

    and activity for unknown reasons, and are thus useful probes of stability-function trade-offs relevant to protein engineering. We report here the first systematic comparison of ABTS-binding to different proteins, i.e. the four isoforms of Trametes versicolor, using a combination of sequence clustering, density...

  16. A phase I study assessing the safety and pharmacokinetics of the thrombospondin-1-mimetic angiogenesis inhibitor ABT-510 with gemcitabine and cisplatin in patients with solid tumors

    NARCIS (Netherlands)

    Gietema, J. A.; Hoekstra, R.; de Vos, F. Y. F. L.; Uges, D. R. A.; van der Gaast, A.; Groen, H. J. M.; Loos, W. J.; Knight, R. A.; Carr, R. A.; Humerickhouse, R. A.; Eskens, F. A. L. M.

    2006-01-01

    Background: The aim of the study was to determine the safety profile, pharmacokinetics and potential drug interactions of the angiogenesis inhibitor ABT-510 combined with gemcitabine-cisplatin chemotherapy in patients with solid tumors. Patients and methods: Patients with advanced solid tumors recei

  17. 吲哚荷尔蒙自由基脉冲辐解光谱及其酸基平衡和还原电位性质研究%The spectral, acid-base equilibrium and reduction potential properties of indole hormone radicals: a pulse radiolysis study

    Institute of Scientific and Technical Information of China (English)

    H He; M Lin; Z Han; Y Muroya; H Kudo; Y Katsumura; M Iwata

    2005-01-01

    The Absorption spectral, acid-base equilibrium potential properties and formation and decay kinetics of four kinds of radicals from natural existing indole hormones were studied by pulse radiolysis.One of the most important properties for these four indolyl hormones, melatonin, 5-methoxygramine (MTA),5-methoxy-N, N-dimethylthytrytamine (DMM TA) and 5-methoxy-N, N-diethylthytrytamine (DEMT A), which are involved in biochemical processes and play crucial roles in many neuropathy and cancer related diseases, is their facile one electron oxidation with formation of radical cations or their conjugated base, the indolyl radicals.Formation kinetics and properties of the radicals were investigated by pulse radiolysis using the Linac accelerator with fast time-resolving optical system in UTNL.In the present study, these radicals were generated through oxidation of the corresponding hormone with azide radical in radiation induced process. Their spectroscopic properties were investigated and it was found that the transient spectra in all these cases exhibit similar absorption and pH dependence: in acidic solution, the radicals are characterized with three absorption maxima around 320-350, 440-460, 520-550nm. The spectra of MTA at various pH were shown as an example. From the absorption changes as a function of pH, two pK values were determined to be around 5 and 9 for the indolyl radicals except for melatonin, in which, only one pK was distinguished to be 4.4. Formation kinetics of the radicals was measured by following the growth of their absorption peaks and it was found that these indolyl derivatives transfer an electron to N3, with different rate constants, i.e.1.2×1010, 4.5×109, 4.9×109, 1.6×109 dm3 mol-1 s-1 for melatonin, MTA, DMMTA, and DEMTA, respectively.Reduction potentials of the radicals vs their molecules were also determined and they are dependent on the pH of medium. At pH 7, the reduction potentials were estimated to be 1.10, 1.18, 1.18, 1.20eV for

  18. Protection of free radical-induced cytotoxicity by 2-O-α-D-glucopyranosyl-L-ascorbic acid in human dermal fibroblasts.

    Science.gov (United States)

    Hanada, Yukako; Iomori, Atsuko; Ishii, Rie; Gohda, Eiichi; Tai, Akihiro

    2014-01-01

    The stable ascorbic acid (AA) derivative, 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G), exhibits vitamin C activity after enzymatic hydrolysis to AA. The biological activity of AA-2G per se has not been studied in detail, although AA-2G has been noted as a stable source for AA supply. The protective effect of AA-2G against the oxidative cell death of human dermal fibroblasts induced by incubating with 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) for 24 h was investigated in this study. AA-2G showed a significant protective effect against the oxidative stress in a concentration-dependent manner. AA-2G did not exert a protective effect during the initial 12 h of incubation, but had a significant protective effect in the later part of the incubation period. Experiments using a α-glucosidase inhibitor and comparative experiments using a stereoisomer of AA-2G confirmed that AA-2G had a protective effect against AAPH-induced cytotoxicity without being converted to AA. Our results provide an insight into the efficacy of AA-2G as a biologically interesting antioxidant and suggest the practical use of AA-2G even before being converted into AA as a beneficial antioxidant.

  19. Relationship between ascorbyl radical intensity and apoptosis-inducing activity.

    Science.gov (United States)

    Sakagami, H; Satoh, K; Ohata, H; Takahashi, H; Yoshida, H; Iida, M; Kuribayashi, N; Sakagami, T; Momose, K; Takeda, M

    1996-01-01

    Ascorbic acid and its related compounds were compared for their ascorbyl radical intensity and apoptosis-inducing activity. Sodium L-ascorbate, L-ascorbic acid, D-isoascorbic acid, sodium 6-beta-O-galactosyl-L-ascorbate and sodium 5,6-benzylidene-L-ascorbate, at the concentration of 1-10 mM, induced apoptotic cell death characterized by cell shrinkage, nuclear fragmentation and internucleosomal DNA cleavage in human promyelocytic leukemic HL-60 cells. On the other hand, L-ascorbic acid-2-phosphate magnesium salt and L-ascorbic acid 2-sulfate did not induce any of these apoptosis-associated characteristics. ESR measurements revealed that all the active compounds were progressively degraded, producing the ascorbyl radical (g = 2.0064, hfc = 0.17 mT) in culture medium, whereas the inactive compounds were stable and did not produce the ascorbyl radical. Cytotoxicity began to appear when the radical intensity exceeded a certain threshold level. In the presence of N-acetyl-L-cysteine, both ascorbyl radical intensity and apoptosis-inducing activity were significantly reduced. These data suggest the possible involvement of the ascorbyl radical in apoptosis induction by ascorbic acid-related compounds. Exposure of HL-60 cells to ascorbic acid or its active derivatives resulted in the rapid elevation of intracellular Ca2+ concentration, which might serve as the initial signal leading to the cell death pathway.

  20. Gallic Acid Ameliorates Cyclophosphamide-Induced Neurotoxicity in Wistar Rats Through Free Radical Scavenging Activity and Improvement in Antioxidant Defense System.

    Science.gov (United States)

    Oyagbemi, Ademola Adetokunbo; Omobowale, Temidayo Olutayo; Saba, Adebowale Bernard; Olowu, Ebunoluwa Racheal; Dada, Racheal Omolola; Akinrinde, Akinleye Stephen

    2016-01-01

    Cyclophosphamide (CPA) is a widely used anticancer chemotherapeutic agent and its toxicity has been associated with its toxic metabolites phosphormide mustard. Therefore, the ameliorative effect of Gallic acid against neurotoxicity was examined in this study. Sixty rats were grouped into 10 rats per group. Group 1 received saline orally. Group 2 received CPA at 100 mg/kg single dose intraperitoneally on day 1. Groups 3 and 4 were treated with Gallic acid (GA) at 60 and 120 mg/kg body weight only for 10 days and also received a single dose of CPA (100 mg/kg) intraperitoneally on day 1, respectively. Rats in groups 5 and 6 received GA at 60 and 120 mg/kg body weight only for 10 days. Groups 3, 4, 5, and 6 received GA orally. The cerebellar and cerebral malondialdehyde (MDA) contents and hydrogen peroxide generation were significantly (p < .05) elevated. The cerebellar and cerebral catalase (CAT), superoxide dismutase and glutathione-S-transferase (GST) activities were significantly (p < .05) reduced in CPA treated group. The activity of glutathione peroxidase (GPx) was significantly increased in rats that were treatment with CPA. Also, nitrite content was significantly elevated in the brain of rats that received the toxic dose of CPA. All these findings suggest that treatment with GA (60 and 120 mg/kg) ameliorated the neurotoxicity induced by CPA via reduction of oxidative stress and increase in antioxidant defense system. Combining all, chemotherapeutic agents with structure/function similar to GA could be of potential benefit to the pharmaceutical industries as an adjuvant in chemotherapy with little or no side effects.

  1. Development of the radical-stable Coprinus cinereus peroxidase (CiP) by blocking the radical attack.

    Science.gov (United States)

    Kim, Su Jin; Joo, Jeong Chan; Kim, Han Sang; Kwon, Inchan; Song, Bong Keun; Yoo, Young Je; Kim, Yong Hwan

    2014-11-10

    Despite the potential use of peroxidases as industrial biocatalysts, their practical application is often impeded due to suicide inactivation by radicals generated in oxidative reactions. Using a peroxidase from Coprinus cinereus (CiP) as a model enzyme, we revealed a dominant factor for peroxidase inactivation during phenol oxidation, and we engineered radical-stable mutants by site-directed mutagenesis of an amino acid residue susceptible to modification by phenoxyl radical. Mass spectrometry analysis of inactivated CiP identified an adduct between F230 and a phenoxyl radical, and subsequently, the F230 residue was mutated to amino acids that resisted radical coupling. Of the F230 mutants, the F230A mutant showed the highest stability against radical inactivation, retaining 80% of its initial activity, while the wild-type protein was almost completely inactivated. The F230A mutant also exhibited a 16-fold higher turnover of the phenol substrate compared with the wild-type enzyme. Furthermore, the F230A mutant was stable during the oxidation of other phenolic compounds, including m-cresol and 3-methoxyphenol. No structural changes were observed by UV-vis and CD spectra of CiP after radical coupling, implying that the F230-phenol radical adduct inactivated CiP by blocking substrate access to the active site. Our novel strategy can be used to improve the stability of other peroxidases inactivated by radicals.

  2. Fatty Acid Composition and Antioxidant Property of the Oils from Oil Palm Produced in Wenchang City, Hainan%海南文昌油棕油脂的脂肪酸组成及抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    夏秋瑜; 李瑞; 唐敏敏; 王威; 雷新涛; 赵松林

    2011-01-01

    采用GC-MS测定了海南文昌小叶杜拉种(E.guineensis-S.L Dura)油棕果中棕榈油(P0)和棕榈仁油(PKO)的脂肪酸组成,并对二者的体外抗氧化活性进行评价.结果表明,PO中总酚含量为(0.014±0.000 2)mg/g,而PKO中未测出多酚;PO及PKO的硫代巴比妥酸值(TBARS)显著低于空白样品;75%PO对DPPH,的清除能力显著高于Vc、苹果酸和儿茶酸,达98.86%,而PKO对DPPH·的清除能力低于对照;PO中多酚提取物(PO-PF)及75% PKO对Fe2+的络合能力显著高于Vc、苹果酸和儿茶酸;PO-PF和75%PO对Fe3+的还原能力显著高于Vc及苹果酸,75% PKO对Fe3+的还原能力与Vc相当.PO-PF及25%~75%PKO对ABTS+·的清除能力优于Vc和苹果酸.%GC-MS was used to detect fatty acid composition of palm oil (PO) and palm kernel oil (PKO) from oil palm (E. Guineensis -S.L.Durd) produced in Wenchang, Hainan, and the antioxidant property of the oils was evaluated. The results showed that the polyphenol content of PO was (0.014±0.000 2) mg/g and which was not detected in PKO. The TBARS value of PO and PKO were obviously lower than the check. The scavenging ability to DPPH radical of 75% PO was 98.86%, which was remarkably higher than Vc, malic acid and catechin, while the scavenging ability to DPPH radical of PKO was lower than the three contrasts. The complexation ability to ferrous iron of 75% PKO and polyphenol fraction of palm oil (PO-PF) were obviously higher than Vc, malic acid and catechin. The reducing capacity to Fe3+ of PO-PF and 75% PO were obviously hither than Vc and malic acid, which of 75% PKO was comparable to Vc. The scavenging rate to ABTS+ radical of PO-PF and 25%~75% PKO were higher than Vc and malic acid.

  3. Resveratrol products resulting by free radical attack

    Science.gov (United States)

    Bader, Yvonne; Quint, R. M.; Getoff, Nikola

    2008-06-01

    Trans-resveratrol ( trans-3,4',5-trihydroxystilbene; RES), which is contained in red wine and many plants, is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. Among other duties, RES has been reported to have anti-carcinogenetic activities, which could be attributed to its antioxidant properties. The degradation of RES was studied under various conditions. The products (aldehydes, carboxylic acids, etc.) generated from RES by the attack of free radicals were registered as a function of the radical concentration (absorbed radiation dose). Based on the obtained data it appears that the OH radicals are initiating the rather complicated process, which involves of the numerous consecutive reactions. A possible starting reaction mechanism is presented.

  4. Resveratrol products resulting by free radical attack

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Yvonne; Quint, R.M. [Section Radiation Biology, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, UZAII, Althanstrasse 14, A-1090 Vienna (Austria); Getoff, Nikola [Section Radiation Biology, Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, UZAII, Althanstrasse 14, A-1090 Vienna (Austria)], E-mail: nikola.getoff@univie.ac.at

    2008-06-15

    Trans-resveratrol (trans-3,4',5-trihydroxystilbene; RES), which is contained in red wine and many plants, is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. Among other duties, RES has been reported to have anti-carcinogenetic activities, which could be attributed to its antioxidant properties. The degradation of RES was studied under various conditions. The products (aldehydes, carboxylic acids, etc.) generated from RES by the attack of free radicals were registered as a function of the radical concentration (absorbed radiation dose). Based on the obtained data it appears that the OH radicals are initiating the rather complicated process, which involves of the numerous consecutive reactions. A possible starting reaction mechanism is presented.

  5. An exploratory study on the peroxyl-radical-scavenging activity of 2,6-dimethyl-5-hepten-2-ol and its heterocyclic analogues

    Science.gov (United States)

    Stobiecka, Agnieszka; Sikora, Magdalena; Bonikowski, Radosław; Kula, Józef

    2016-03-01

    The structural properties and radical scavenging activity of 2,6-dimethyl-5-hepten-2-ol (1) and its new heterocyclic analogues, i.e. 2-methyl-4-(5-methylfuran-2-yl)-butan-2-ol (2) and 2-methyl-4-(5-methylthiophen-2-yl)-butan-2-ol (3) and have been studied by using the experimental and theoretical methods for the first time. Activity of title compounds against the peroxyl radical was determined by using standard fluorimetric test, i.e. the Oxygen Radical Absorbance Capacity assay (ORACFL). Furthermore, the electron-donating ability of odorants has been evaluated by using colorimetric ABTS assay. According to the experimental results obtained from the ORACFL test 2,6-dimethyl-5-hepten-2-ol was characterized by the highest activity in comparison with the novel counterparts. Nevertheless, all investigated compounds exhibited pronounced anti-peroxyl radical activity comparable to that exerted by the one of the most prominent antioxidant among the monoterpene alcohols, i.e. by linalool. On the other hand, the title compounds exerted relatively low capacity to quench the radical cation of ABTS. Theoretical calculations based on the Density Functional Theory (DFT) method with the hybrid functional B3LYP were carried out in order to investigate selected structural and electronic properties including the geometrical parameters as well as the energy of frontier molecular orbitals of parent molecules and the resulting radicals. Furthermore, the possible mechanism of peroxyl-radical-scavenging has been determined by using the thermodynamic descriptors such as the bond dissociation enthalpies (BDEs) and ionization potentials (IPs). These theoretical data pointed out the relevance of HAT mechanism in the peroxyl-radical-scavenging exhibited by 2,6-dimethyl-5-hepten-2-ol and its new heterocyclic analogues in polar and non-polar medium.

  6. Gangs, Terrorism, and Radicalization

    Directory of Open Access Journals (Sweden)

    Scott Decker

    2011-01-01

    Full Text Available What can street gangs tell us about radicalization and extremist groups? At first glance, these two groups seem to push the boundaries of comparison. In this article, we examine the important similarities and differences across criminal, deviant, and extremist groups. Drawing from research on street gangs, this article explores issues such as levels of explanation,organizational structure, group process, and the increasingly important role of technology and the Internet in the context of radicalization. There are points of convergence across these groups, but it is important to understand the differences between these groups. This review finds little evidence to support the contention that American street gangs are becoming increasingly radicalized. This conclusion is based largely on organizational differences between gangs and terror groups.

  7. Sexuality Following Radical Prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Serefoglu, Ege C; Albersen, Maarten;

    2017-01-01

    INTRODUCTION: Radical prostatectomies can result in urinary incontinence and sexual dysfunction. Traditionally, these issues have been studied separately, and the sexual problem that has received the most focus has been erectile dysfunction. AIM: To summarize the literature on sexually related side...... effects and their consequences after radical prostatectomy and focus on the occurrence and management of problems beyond erectile dysfunction. METHODS: The literature on sexuality after radical prostatectomy was reviewed through a Medline search. Original research using quantitative and qualitative...... methodologies was considered. Priority was given to studies exploring aspects of sexuality other than erectile function. MAIN OUTCOME MEASURES: The prevalence, predictive factors, and management of post-prostatectomy sexual problems beyond erectile dysfunction. RESULTS: Most patients will develop urinary...

  8. The amorphous solid dispersion of the poorly soluble ABT-102 forms nano/microparticulate structures in aqueous medium: impact on solubility

    Directory of Open Access Journals (Sweden)

    Frank KJ

    2012-11-01

    Full Text Available Kerstin J Frank,1,3 Ulrich Westedt,2 Karin M Rosenblatt,2 Peter Hölig,2 Jörg Rosenberg,2 Markus Mägerlein,2 Gert Fricker,3 Martin Brandl11Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark; 2Abbott GmbH and Co. KG, Ludwigshafen, Germany; 3Department of Pharmaceutical Technology, University of Heidelberg, Heidelberg, GermanyAbstract: Amorphous solid dispersions (ASDs are a promising formulation approach for poorly soluble active pharmaceutical ingredients (APIs, because they ideally enhance both dissolution rate and solubility. However, the mechanism behind this is not understood in detail. In the present study, we investigated the supramolecular and the nano/microparticulate structures that emerge spontaneously upon dispersion of an ASD in aqueous medium and elucidated their influence on solubility. The ASD, prepared by hot melt extrusion, contained the poorly soluble ABT-102 (solubility in buffer, 0.05 µg/mL, a hydrophilic polymer, and three surfactants. The apparent solubility of ABT-102 from the ASD-formulation was enhanced up to 200 times in comparison to crystalline ABT-102. At the same time, the molecular solubility, as assessed by inverse equilibrium dialysis, was enhanced two times. Asymmetrical flow field-flow fractionation in combination with a multiangle light-scattering detector, an ultraviolet detector, and a refractometer enabled us to separate and identify the various supramolecular assemblies that were present in the aqueous dispersions of the API-free ASD (placebo and of binary/ternary blends of the ingredients. Thus, the supramolecular assemblies with a molar mass between 20,000 and 90,000 could be assigned to the polyvinylpyrrolidone/vinyl acetate 64, while two other kinds of assemblies were assigned to different surfactant assemblies (micelles. The amount of ABT-102 remaining associated with each of the assemblies upon fractionation was quantified offline with high

  9. Beyond Radical Educational Cynicism.

    Science.gov (United States)

    Wood, George H.

    1982-01-01

    An alternative is presented to counter current radical arguments that the schools cannot bring about social change because they are instruments of capitalism. The works of Samuel Bowles, Herbert Gintis, and Louis Althusser are discussed. Henry Giroux's "Ideology, Culture and the Process of Schooling" provides an alternative to cynicism.…

  10. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  11. Electromeric rhodium radical complexes

    NARCIS (Netherlands)

    Puschmann, F.F.; Harmer, J.; Stein, D.; Rüegger, H.; de Bruin, B.; Grützmacher, H.

    2010-01-01

    Radical changes: One single P-Rh-P angle determines whether the odd electron in the paramagnetic complex [Rh(trop2PPh)(PPh3)] is delocalized over the whole molecule (see picture, blue) or is localized on the P—Rh unit (red). The two energetically almost degenerate electromers exist in a fast equilib

  12. Violent Radicalization in Europe

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja

    2010-01-01

    When, why, and how do people living in a democracy become radicalized to the point of being willing to use or directly support the use of terrorist violence against fellow citizens? This question has been at the center of academic and public debate over the past years as terrorist attacks...

  13. Radical School Reform.

    Science.gov (United States)

    Gross, Beatrice, Ed.; Gross, Ronald, Ed.

    This book provides a comprehensive examination of the nature of the school crisis and the ways in which radical thinkers and educators are dealing with it. Excerpts from the writings of Jonathan Kozol, John Holt, Kenneth Clark, and others are concerned with the realities of education in ghettos and suburbs. Paul Goodman, Marshall McLuhan, Sylvia…

  14. Homegrown religious radicalization

    DEFF Research Database (Denmark)

    Khawaja, Iram

    and their families. Existing literature and ways of thinking about the social psychological process of radicalization will be reviewed, such as social identity theory and transformative learning theory, and a theoretical framework based on a focus on belonging, recognition and the sense of community will be proposed...

  15. On Radical Feminism

    Institute of Scientific and Technical Information of China (English)

    翟良锴

    2015-01-01

    <正>All men are created equal.For centuries,human have been struggling for their rights.Women,as a special social force,are fighting vigorously for their equal rights with men.According to an introduction to feminism,there are three main types of feminism:socialist,reformist and radical(Feminism 101).In order

  16. A randomized phase I/II study of ABT-888 in combination with temozolomide in recurrent temozolomide resistant glioblastoma: an NRG oncology RTOG group study.

    Science.gov (United States)

    Robins, H Ian; Zhang, Peixin; Gilbert, Mark R; Chakravarti, Arnab; de Groot, John F; Grimm, Sean A; Wang, Fen; Lieberman, Frank S; Krauze, Andra; Trotti, Andy M; Mohile, Nimish; Kee, Andrew Y J; Colman, Howard; Cavaliere, Robert; Kesari, Santosh; Chmura, Steven J; Mehta, Minesh

    2016-01-01

    This study tested the hypothesis that ABT-888 (velparib), a poly (ADP-ribose) polymerase (PARP) inhibitor, can modulate temozolomide (TMZ) resistance in recurrent TMZ refractory glioblastoma patients. The combination regimen (TMZ/ABT-888) was tested using two randomized schedules (5 vs. 21 days), with 6-month progression free survival (PFS6) as the primary endpoint. The maximum tolerated dose (MTD) for TMZ using the 21 day of 28 TMZ schedule, in concert with 40 mg BID ABT-888 was determined in a phase I portion of this study, and previously reported to be 75 mg/m(2) (arm1). The MTD for ABT-888 (40 mg BID) and the 5 of 28 day TMZ (150-200 mg/m(2)) schedule was known from prior trials (arm2). Two cohorts were studied: bevacizumab (BEV) naïve (n = 151), and BEV refractory (n = 74). Overall ten patients were ineligible. The incidence rate of grade 3/4 myelosuppression over all was 20.0 %. For the BEV refractory cohort, the PFS 6 was 4.4 %; for the BEV naïve cohort, PFS6 was 17 %. Overall survival was similar for both arms in both the BEV naïve [median survival time (MST) 10.3 M; 95 % CI 8.4-12] and BEV refractory cohort (MST 4.7 M; 95 %CI 3.5-5.6). The median PFS was essentially the same for both arms and both cohorts at ~2.0 M (95 % CI 1.9-2.1).

  17. Upregulating Noxa by ER stress, celastrol exerts synergistic anti-cancer activity in combination with ABT-737 in human hepatocellular carcinoma cells.

    Science.gov (United States)

    Zhu, Hong; Yang, Wei; He, Ling-juan; Ding, Wan-jing; Zheng, Lin; Liao, Si-da; Huang, Ping; Lu, Wei; He, Qiao-jun; Yang, Bo

    2012-01-01

    The human hepatocellular carcinoma (HCC) represents biologically aggressive and chemo-resistant cancers. Owing to the low affinity with the apoptotic factor Mcl-1, the BH3 mimetic drug ABT-737 failed to exert potent cancer-killing activities in variety of cancer models including HCC. The current study demonstrated that combining ABT-737 and Celastrol synergistically suppressed HCC cell proliferation, and induced apoptosis which was accompanied with the activation of caspase cascade and release of cytochrome c from mitochondria. Further study revealed that the enhanced Noxa caused by Celastrol was the key factor for the synergy, since small interfering RNA-mediated knockdown of Noxa expression in HCC cells resulted in decreased apoptosis and attenuated anti-proliferative effects of the combination. In addition, our study unraveled that, upon Celastrol exposure, the activation of endoplasmic reticulum (ER) stress, specifically, the eIF2α-ATF4 pathway played indispensable roles in the activation of Noxa, which was validated by the observation that depletion of ATF4 significantly abrogated the Noxa elevation by Celastrol. Our findings highlight a novel signaling pathway through which Celastrol increase Noxa expression, and suggest the potential use of ATF4-mediated regulation of Noxa as a promising strategy to improve the anti-cancer activities of ABT-737.

  18. Upregulating Noxa by ER stress, celastrol exerts synergistic anti-cancer activity in combination with ABT-737 in human hepatocellular carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Hong Zhu

    Full Text Available The human hepatocellular carcinoma (HCC represents biologically aggressive and chemo-resistant cancers. Owing to the low affinity with the apoptotic factor Mcl-1, the BH3 mimetic drug ABT-737 failed to exert potent cancer-killing activities in variety of cancer models including HCC. The current study demonstrated that combining ABT-737 and Celastrol synergistically suppressed HCC cell proliferation, and induced apoptosis which was accompanied with the activation of caspase cascade and release of cytochrome c from mitochondria. Further study revealed that the enhanced Noxa caused by Celastrol was the key factor for the synergy, since small interfering RNA-mediated knockdown of Noxa expression in HCC cells resulted in decreased apoptosis and attenuated anti-proliferative effects of the combination. In addition, our study unraveled that, upon Celastrol exposure, the activation of endoplasmic reticulum (ER stress, specifically, the eIF2α-ATF4 pathway played indispensable roles in the activation of Noxa, which was validated by the observation that depletion of ATF4 significantly abrogated the Noxa elevation by Celastrol. Our findings highlight a novel signaling pathway through which Celastrol increase Noxa expression, and suggest the potential use of ATF4-mediated regulation of Noxa as a promising strategy to improve the anti-cancer activities of ABT-737.

  19. Delivery of vanillin by poly(lactic-acid) nanoparticles: Development, characterization and in vitro evaluation of antioxidant activity

    Energy Technology Data Exchange (ETDEWEB)

    Dalmolin, Luciana Facco; Khalil, Najeh Maissar; Mainardes, Rubiana Mara, E-mail: rubianamainardes@hotmail.com

    2016-05-01

    Poly(lactic acid) (PLA) nanoparticles containing vanillin were prepared using an emulsion-solvent evaporation technique and were characterized and assessed for their in vitro antioxidant potential. Physicochemical properties of the nanoparticles were characterized by size, polydispersity index, zeta potential, encapsulation efficiency and stability. Solid state and thermal properties were assessed using X-ray diffraction and differential scanning calorimetry, while in vitro drug release profile was also evaluated. Results showed PLA nanoparticles having a characteristic amorphous structure, sizes in the range of 240 nm with high homogeneity in size distribution, zeta potential of − 22 mV and vanillin encapsulation efficiency of 41%. In vitro release study showed a slow and sustained release of vanillin governed by diffusion. Nanoparticles were stable over a period of three months. Antioxidant ability of the vanillin-loaded PLA nanoparticles in scavenging the radical 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was inferior to free vanillin and due to its prolonged release showed a profile that was both time and concentration dependent, while free vanillin showed concentration-dependent activity. The study concluded that PLA nanoparticles are potential carriers for vanillin delivery. - Highlights: • Vanillin was nanoencapsulated in poly(lactic acid) (PLA) nanoparticles. • Mean particle size was 240 nm and vanillin encapsulation efficiency was 41%. • A prolonged and biphasic vanillin release occurred with 20% released after 120 h. • Vanillin nanoparticles exhibited time/concentration dependent antioxidant activity.

  20. Coumestan inhibits radical-induced oxidation of DNA: is hydroxyl a necessary functional group?

    Science.gov (United States)

    Xi, Gao-Lei; Liu, Zai-Qun

    2014-06-18

    Coumestan is a natural tetracycle with a C═C bond shared by a coumarin moiety and a benzofuran moiety. In addition to the function of the hydroxyl group on the antioxidant activity of coumestan, it is worth exploring the influence of the oxygen-abundant scaffold on the antioxidant activity as well. In this work, seven coumestans containing electron-withdrawing and electron-donating groups were synthesized to evaluate the abilities to trap 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(•+)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, respectively, and to inhibit the oxidations of DNA mediated by (•)OH, Cu(2+)/glutathione (GSH), and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), respectively. It was found that all of the coumestans used herein can quench the aforementioned radicals and can inhibit (•)OH-, Cu(2+)/GSH-, and AAPH-induced oxidations of DNA. In particular, substituent-free coumestan exhibits higher ability to quench DPPH and to inhibit AAPH-induced oxidation of DNA than Trolox. In addition, nonsubstituted coumestan shows a similar ability to inhibit (•)OH- and Cu(2+)/GSH-induced oxidations of DNA relative to that of Trolox. The antioxidant effectiveness of the coumestan can be attributed to the lactone in the coumarin moiety and, therefore, a hydroxyl group may not be a necessary functional group for coumestan to be an antioxidant.

  1. Biocompatible and biodegradable poly(Tannic Acid) hydrogel with antimicrobial and antioxidant properties.

    Science.gov (United States)

    Sahiner, Nurettin; Sagbas, Selin; Sahiner, Mehtap; Silan, Coskun; Aktas, Nahit; Turk, Mustafa

    2016-01-01

    A novel resourceful bulk poly(Tannic Acid) (p(TA)) hydrogel was prepared by crosslinking TA molecules with an epoxy crosslinker, trimethylolpropane triglycidyl ether (TMPGDE), in an autoclave at 90°C for 2h. The obtained p(TA) hydrogels were in disk form and have highly porous morphology. The swelling characteristics of p(TA) hydrogels were investigated in wound healing pH conditions of pH 5.4, 7.4, and 9 at 37.5°C, and the hydrogels showed good swelling and moisture content behavior. Especially, p(TA) hydrogels were found to be sensitive to pH 9 with 1669% maximum swelling. P(TA) hydrogels were completely degraded at pH 9 hydrolytically in 9 days. Total phenol contents and the effects of scavenging ABTS(+) radicals of degraded p(TA) hydrogels at pH 5.4, 7.4, and 9 were evaluated and calculated in terms of gallic acid equivalent and trolox equivalent antioxidant capacity, respectively, and found to be very effective. Moreover, degraded p(TA) hydrogels display strong antimicrobial behavior against gram positive Staphylococcus aureus, Bacillus subtilis, gram negative Pseudomonas aeruginosa bacteria strains and Candida albicans fungus strain. The WST-1 results indicated that bulk p(TA) hydrogels have no cyctotoxicity to the L929 fibroblast cell line in vitro.

  2. Influence of gallic acid on α-amylase and α-glucosidase inhibitory properties of acarbose

    Directory of Open Access Journals (Sweden)

    Ganiyu Oboh

    2016-07-01

    Full Text Available Acarbose is an antidiabetic drug which acts by inhibiting α-amylase and α-glucosidase activities but with deleterious side effects. Gallic acid (GA is a phenolic acid that is widespread in plant foods. We therefore investigated the influence of GA on α-amylase and α-glucosidase inhibitory properties of acarbose (in vitro. Aqueous solutions of acarbose and GA were prepared to a final concentration of 25μM each. Thereafter, mixtures of the samples (50% acarbose + 50% GA; 75% acarbose+25% GA; and 25% acarbose+75% GA were prepared. The results revealed that the combination of 50% acarbose and 50% GA showed the highest α-glucosidase inhibitory effect, while 75% acarbose+25% GA showed the highest α-amylase inhibitory effect. Furthermore, all the samples caused the inhibition of Fe2+-induced lipid peroxidation (in vitro in rat pancreatic tissue homogenate, with the combination of 50% acarbose and 50% GA causing the highest inhibition. All the samples also showed antioxidant properties (reducing property, 2,2'-azino-bis (-3-ethylbenzthiazoline-6-sulphonate [ABTS*] and 1,1-diphenyl-2-picrylhydrazyl [DPPH] free radicals scavenging abilities, and Fe2+ chelating ability. Therefore, combinations of GA with acarbose could be employed as antidiabetic therapy, with a possible reduction of side effects of acarbose; nevertheless, the combination of 50% acarbose and 50% GA seems the best.

  3. Free radical scavenging abilities of polypeptide from Chlamys farreri

    Science.gov (United States)

    Han, Zhiwu; Chu, Xiao; Liu, Chengjuan; Wang, Yuejun; Mi, Sun; Wang, Chunbo

    2006-09-01

    We investigated the radical scavenging effect and antioxidation property of polypeptide extracted from Chlamys farreri (PCF) in vitro using chemiluminescence and electron spin resonance (ESR) methods. We examined the scavenging effects of PCF on superoxide anions (O{2/-}), hydroxyl radicals (OH·), peroxynitrite (ONOO-) and the inhibiting capacity of PCF on peroxidation of linoleic acid. Our experiment suggested that PCF could scavenge oxygen free radicals including superoxide anions (O{2/-}) (IC50=0.3 mg/ml), hydroxyl radicals (OH·) (IC50=0.2 μg/ml) generated from the reaction systems and effectively inhibit the oxidative activity of ONOO- (IC50=0.2 mg/ml). At 1.25 mg/ml of PCF, the inhibition ratio on lipid peroxidation of linoleic acid was 43%. The scavenging effect of PCF on O{2/-}, OH· and ONOO- free radicals were stronger than those of vitamin C but less on lipid peroxidation of linoleic acid. Thus PCF could scavenge free radicals and inhibit the peroxidation of linoleic acid in vitro. It is an antioxidant from marine products and potential for industrial production in future.

  4. Free radical scavenging abilities of polypeptide from Chlamys farreri

    Institute of Scientific and Technical Information of China (English)

    HAN Zhiwu; CHU Xiao; LIU Chengjuan; WANG Yuejun; SUN Mi; WANG Chunbo

    2006-01-01

    We investigated the radical scavenging effect and antioxidation property of polypeptide extracted from Chlamys farreri (PCF) in vitro using chemiluminescence and electron spin resonance (ESR) methods. We examined the scavenging effects of PCF on superoxide anions (O-2), hydroxyl radicals (OH·), peroxynitrite (ONOO-) and the inhibiting capacity of PCF on peroxidation of linoleic acid. Our experiment suggested that PCF could scavenge oxygen free radicals including superoxide anions (O-2) (IC50 =0.3 mg/ml), hydroxyl radicals (OH·) (IC50 = 0.2 μg/ml) generated from the reaction systems and effectively inhibit the oxidative activity of ONOO- (IC50 = 0.2 mg/ml). At 1.25 mg/ml of PCF, the inhibition ratio on lipid peroxidation of linoleic acid was 43 %. The scavenging effect of PCF on (O-2), OH·and ONOO- free radicals were stronger than those of vitamin C but less on lipid peroxidation of linoleic acid. Thus PCF could scavenge free radicals and inhibit the peroxidation of linoleic acid in vitro. It is an antioxidant from marine products and potential for industrial production in future.

  5. A hydrogen-donating monohydroxamate scavenges ferryl myoglobin radicals

    DEFF Research Database (Denmark)

    Cooper, C E; Green, E S; Rice-Evans, C A

    1994-01-01

    of the high spin metmyoglobin (g = 6) signal is consistent with these findings. At this low peroxide concentration there is no evidence for iron release from the haem. At least two free radicals are detectable by EPR immediately after H2O2 addition, but decay completely after ten minutes. However, a longer......-lived radical is observed at lower concentrations that is still present after 90 minutes. The monohydroxamate N-methylbutyro-hydroxamic acid (NMBH) increases the rate of decay of the fenyl species. In the presence of NMBH, none of the protein-bound free radicals are detectable; instead nitroxide radicals...... produced by oxidation of the hydroxamate group are observed. Similar results are observed with the trihydroxamate, desferrioxamine. "Ferryl myoglobin" is still able to initiate lipid peroxidation even after the short-lived protein free radicals are no longer detectable (E.S.R. Newman, C.A. Rice-Evans and M...

  6. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II) Complexes.

    Science.gov (United States)

    Wang, Xiangcong; Yan, Maocai; Wang, Qibao; Wang, Huannan; Wang, Zhengyang; Zhao, Jiayi; Li, Jing; Zhang, Zhen

    2017-01-20

    Indole-2-carboxylic acid copper complex (ICA-Cu) was successfully prepared and characterized through elemental analysis, IR, UV-Vis, ¹H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu₂(C₉H₆O₂N)₄(H₂O)₂]·2H₂O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA) was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB) from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant KSV value was 3.99 × 10⁴ M(-1). The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na⁺ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, a hydroxyl radical (OH) scavenging assay, and a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM), followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively). The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT) assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell

  7. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Xiangcong Wang

    2017-01-01

    Full Text Available Indole-2-carboxylic acid copper complex (ICA-Cu was successfully prepared and characterized through elemental analysis, IR, UV-Vis, 1H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu2(C9H6O2N4(H2O2]·2H2O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant KSV value was 3.99 × 104 M−1. The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na+ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH assay, a hydroxyl radical (OH scavenging assay, and a 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM, followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively. The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell lines. Also

  8. Probability and radical behaviorism

    Science.gov (United States)

    Espinosa, James M.

    1992-01-01

    The concept of probability appears to be very important in the radical behaviorism of Skinner. Yet, it seems that this probability has not been accurately defined and is still ambiguous. I give a strict, relative frequency interpretation of probability and its applicability to the data from the science of behavior as supplied by cumulative records. Two examples of stochastic processes are given that may model the data from cumulative records that result under conditions of continuous reinforcement and extinction, respectively. PMID:22478114

  9. Probability and radical behaviorism

    OpenAIRE

    Espinosa, James M.

    1992-01-01

    The concept of probability appears to be very important in the radical behaviorism of Skinner. Yet, it seems that this probability has not been accurately defined and is still ambiguous. I give a strict, relative frequency interpretation of probability and its applicability to the data from the science of behavior as supplied by cumulative records. Two examples of stochastic processes are given that may model the data from cumulative records that result under conditions of continuous reinforc...

  10. Radical chic, javisst!

    NARCIS (Netherlands)

    Hartle, J.F.

    2012-01-01

    Det är lätt att raljera över engagerade människor, i synnerhet när engagemanget framstår som ytligt och chict snarare än grundläggande och autentiskt. Men vad ligger bakom ett sådant avfärdande? Johan Frederik Hartle läser om Tom Wolfes klassiska essä "Radical Chic" och visar hur Wolfe −− genom att

  11. Women and radicalization

    OpenAIRE

    Badran, Margot

    2006-01-01

    The paper focuses on women and radicalization within the context of Muslim societies (majority, minority, and half Muslim) societies and groups, mainly in Asia and Africa. The basic argument advanced in this paper is that Islamic feminism with its gender-egalitarian discourse and practices has a major role to play in the empowerment of Muslim women—and of men and society as a whole—and should be brought to bear in devising policy, strategy, and tools.

  12. Radical substitution with azide

    DEFF Research Database (Denmark)

    Pedersen, Christian Marcus; Marinescu, Lavinia Georgeta; Bols, Mikael

    2005-01-01

    and the substrate. A primary deuterium kinetic isotope effect was found for the azidonation of benzyl ethers both with TMSN3-PhI(OAc)2 and with IN3. Also a Hammett free energy relationship study of this reaction showed good correlation with sigma+ constants giving with rho-values of -0.47 for TMSN3-PhI(OAc)2 and -0.......39 for IN3. On this basis a radical mechanism of the reaction was proposed....

  13. [Radical prostatectomy - pro robotic].

    Science.gov (United States)

    Gillitzer, R

    2012-05-01

    Anatomical radical prostatectomy was introduced in the early 1980s by Walsh and Donker. Elucidation of key anatomical structures led to a significant reduction in the morbidity of this procedure. The strive to achieve similar oncological and functional results to this gold standard open procedure but with further reduction of morbidity through a minimally invasive access led to the establishment of laparoscopic prostatectomy. However, this procedure is complex and difficult and is associated with a long learning curve. The technical advantages of robotically assisted surgery coupled with the intuitive handling of the device led to increased precision and shortening of the learning curve. These main advantages, together with a massive internet presence and aggressive marketing, have resulted in a rapid dissemination of robotic radical prostatectomy and an increasing patient demand. However, superiority of robotic radical prostatectomy in comparison to the other surgical therapeutic options has not yet been proven on a scientific basis. Currently robotic-assisted surgery is an established technique and future technical improvements will certainly further define its role in urological surgery. In the end this technical innovation will have to be balanced against the very high purchase and running costs, which remain the main limitation of this technology.

  14. Free radical scavenging property and antiproliferative activity of Rhodiola imbricata Edgew extracts in HT-29 human colon cancer cells

    Institute of Scientific and Technical Information of China (English)

    Ravichandran Senthilkumar; Thangaraj Parimelazhagan; Om Prakash Chaurasia; RB Srivastava

    2013-01-01

    Objective: To investigate the in vitro antioxidant and antiproliferative activity of rhizome extracts of Rhodiola imbricata (R. imbricata) in HT-29 human colon cancer cell line. Methods: The successively extracted rhizome of R. imbricata using various solvents was analyzed for their total phenolics, tannins and flavonoid contents. In vitro antioxidant activity was evaluated by employing different assays, including DPPH, ABTS radical scavenging assays, FRAP, phosphomolybdenum reduction assay, superoxide anion, hydroxyl radical scavenging activities and metal chelating ability. Results: Acetone and methanol extracts recorded higher phenolic content and showed comparable antioxidant activity with standard reference. Additionally, they also inhibited the proliferation of HT-29 cells upon treatment at higher concentration (200 μg/mL) (acetone and methanol, 84% and 84%, respectively). On examination acetone extract exhibited antiproliferative activity in a concentration dependent manner whereas, methanol extract showed both dose dependent and time dependent inhibitory activity. Conclusions: The results obtained justify the traditional usage of R. imbricata from their promising antioxidant activity.

  15. Radical production from photosensitization of imidazoles

    Science.gov (United States)

    Corral Arroyo, P.; Gonzalez, L.; Steimer, S.; Aellig, R.; Volkamer, R. M.; George, C.; Bartels-Rausch, T.; Ammann, M.

    2015-12-01

    Reactions promoted by light are key in atmospheric chemistry. Some of them occur in the condensed phase of aerosols containing light absorbing organic compounds (George et al., 2015). This work explores the radical reactions initiated by near-UV light in mixtures of citric acid (CA) and imidazole-2-carboxaldehyde (IC) using NO as a probe molecule for HO2, by means of coated wall flow tube experiments. Citric acid may act as H atom or electron donor in condensed phase radical cycles. IC may act as a photosensitizer. The loss of NO was measured by a chemiluminescence detector. The dependence of the NO loss on the NO concentration, the IC/CA ratio in the film, relative humidity, light intensity, oxygen molar fraction were investigated as well as the HONO and NO2 yields. We also added halide salts to investigate the effect of a competing electron donor in the system and the output of halogens to the gas phase. We found a correlation between the loss of NO above the film and the molar ratio of IC/CA and the light intensity. The variation of the NO loss with oxygen corroborates a mechanism, in which the triplet excited state of IC is reduced by citric acid, to a reduced ketyl radical that transfers an electron to molecular oxygen, which in turn leads to production of HO2 radicals. Therefore, the NO loss in the gas phase is related to the production of HO2 radicals. Relative humidity had a strong impact on the HO2 output, which shows a maximum production rate at around 30%. The addition of halide ions (X- = Cl-, Br-, I-) increases the HO2 output at low concentration and decrease it at higher concentration when X2- radical ions likely scavenge HO2. We could preliminarily quantify for the first time the contribution of these processes to the oxidative capacity in the atmosphere and conclude that their role is significant for aerosol aging and potentially a significant source of halogen compounds to the gas phase.

  16. Evaluation of free radical scavenging capacity and antioxidative damage effect of resveratrol-nanostructured lipid carriers

    Science.gov (United States)

    Jin, Ju; Shi, Fan; Li, Qiu-wen; Li, Pei-shan; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

    2016-03-01

    Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical(ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, resveratrol loaded nanostructured lipid carriers (Res-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Res-NLC on free radical scavenging capacity and antioxidative damage is investigated. The particle size and zeta potential of Res-NLC were 139.3 ± 1.7 nm and -11.21 ± 0.41 mV, respectively. By free radical scavenging assays, the IC50 value of Res-NLC were 19.25, 5.29 μg/mL with DPPH, ABTS assay respectively, and 0.161 mg ferrous sulfate/1 mg Res-NLC with FRAP assay; and by AAPH-induced oxidative injury cell model assay, Res-NLC showed the strong protective effect against the human liver tumor HepG2 cell oxidative stress damage. These results indicated that the antioxidant properties of Res-NLC hold great potential used as an alternative to more toxic synthetic antioxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

  17. Catalysis of Radical Reactions: A Radical Chemistry Perspective.

    Science.gov (United States)

    Studer, Armido; Curran, Dennis P

    2016-01-04

    The area of catalysis of radical reactions has recently flourished. Various reaction conditions have been discovered and explained in terms of catalytic cycles. These cycles rarely stand alone as unique paths from substrates to products. Instead, most radical reactions have innate chains which form products without any catalyst. How do we know if a species added in "catalytic amounts" is a catalyst, an initiator, or something else? Herein we critically address both catalyst-free and catalytic radical reactions through the lens of radical chemistry. Basic principles of kinetics and thermodynamics are used to address problems of initiation, propagation, and inhibition of radical chains. The catalysis of radical reactions differs from other areas of catalysis. Whereas efficient innate chain reactions are difficult to catalyze because individual steps are fast, both inefficient chain processes and non-chain processes afford diverse opportunities for catalysis, as illustrated with selected examples.

  18. Gnosticism and Radical Feminism

    DEFF Research Database (Denmark)

    Cahana, Jonathan

    2016-01-01

    and place demand an explanation; my attempt to do so also takes into account the important differences between the gnostic and the radical feminist postures, notably the latter belief in progress and the former nostalgia for an ungendered era. Both the similarities and the differences, however, may offer...... support for approaching Gnosticism as first and foremost a cultural phenomenon (albeit exhibiting religious “symptoms”), and I attempt to show that such an approach can help to solve the recurrent problem of defining Gnosticism....

  19. Kinetics and mechanism of protection of thymine from sulphate radical anion under anoxic conditions

    Indian Academy of Sciences (India)

    M Sudha Swaraga; M Adinarayana

    2003-04-01

    The rates of photooxidation of thymine in presence of peroxydisulphate (PDS) have been determined by measuring the absorbance of thymine at 264 nm spectrophotometrically. The rates and the quantum yields () of oxidation of thymine by sulphate radical anion have been determined in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation of thymine suggesting that caffeic acid acts as an efficient scavenger of SO$^{\\bullet -}_{4}$ and protects thymine from it. Sulphate radical anion competes for thymine as well as for caffeic acid. The rate constant of sulphate radical anion with caffeic acid has been calculated to be 1.24 × 1010 dm3 mol-1 s-1. The quantum yields of photooxidation of thymine have been calculated from the rates of oxidation of thymine and the light intensity absorbed by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined quantum yields (exptl) and the quantum yields calculated (cl) assuming caffeic acid acting only as a scavenger of SO$^{\\bullet -}_{4}$ radicals show that exptl values are lower than cl values. The ' values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected for SO$^{\\bullet-}_{4}$ scavenging by caffeic acid, are also found to be greater than exptl values. These observations suggest that the thymine radicals are repaired by caffeic acid in addition to scavenging of sulphate radical anions.

  20. Experimental and computational thermochemical study of sulfur-containing amino acids: L-cysteine, L-cystine, and L-cysteine-derived radicals. S-S, S-H, and C-S bond dissociation enthalpies.

    Science.gov (United States)

    Roux, Maria Victoria; Foces-Foces, Concepción; Notario, Rafael; da Silva, Manuel A V Ribeiro; da Silva, Maria das Dores M C Ribeiro; Santos, Ana Filipa L O M; Juaristi, Eusebio

    2010-08-19

    This paper reports an experimental and theoretical study of the standard (p(degrees) = 0.1 MPa) molar enthalpies of formation at T = 298.15 K of the sulfur-containing amino acids l-cysteine [CAS 52-90-4] and l-cystine [CAS 56-89-3]. The standard (p(degrees) = 0.1 MPa) molar enthalpies of formation of crystalline l-cysteine and l-cystine were calculated from the standard molar energies of combustion, in oxygen, to yield CO2(g) and H2SO4.115H2O, measured by rotating-bomb combustion calorimetry at T = 298.15 K. The vapor pressures of l-cysteine were measured as function of temperature by the Knudsen effusion mass-loss technique. The standard molar enthalpy of sublimation, at T = 298.15 K, was derived from the Clausius-Clapeyron equation. The experimental values were used to calculate the standard (p(degrees) = 0.1 MPa) enthalpy of formation of l-cysteine in the gaseous phase, DeltafH(degrees)m(g) = -382.6 +/- 1.8 kJ x mol-1. Due to the low vapor pressures of l-cystine and since this compound decomposes at the temperature range required for a possible sublimation, it was not possible to determine its enthalpy of sublimation. Standard ab initio molecular orbital calculations at the G3(MP2)//B3LYP and/or G3 levels were performed. Enthalpies of formation, using atomization and isodesmic reactions, were calculated and compared with experimental data. A value of -755 +/- 10 kJ x mol-1 was estimated for the enthalpy of formation of cystine. Detailed inspections of the molecular and electronic structures of the compounds studied were carried out. Finally, bond dissociation enthalpies (BDE) of S-H, S-S, and C-S bonds, and enthalpies of formation of l-cysteine-derived radicals, were also computed.

  1. A Modified Method for Studying Behavioral Paradox of Antioxidants and Their Disproportionate Competitive Kinetic Effect to Scavenge the Peroxyl Radical Formation

    Directory of Open Access Journals (Sweden)

    Nusrat Masood

    2014-01-01

    Full Text Available We have described a modified method for evaluating inhibitor of peroxyl radicals, a well-recognized and -documented radical involved in cancer initiation and promotion as well as diseases related to oxidative stress and ageing. We are reporting hydrophilic and lipophilic as well as natural and synthetic forms of antioxidants revealing a diversified behaviour to peroxyl radical in a dose-dependent manner (1 nM–10 μM. A simple kinetic model for the competitive oxidation of an indicator molecule (ABTS and a various antioxidant by a radical (ROO• is described. The influences of both the concentration of antioxidant and duration of reaction (70 min on the inhibition of the radical cation absorption are taken into account while determining the activity. The induction time of the reaction was also proposed as a parameter enabling determination of antioxidant content by optimizing and introducing other kinetic parameters in 96-well plate assays. The test evidently improves the original PRTC (peroxyl radical trapping capacity assay in terms of the amount of chemical used, simultaneous tracking, that is, the generation of the radical taking place continually and the kinetic reduction technique (area under curve, peak value, slope, and Vmax.

  2. [Initiation and inhibition of free-radical processes in biochemical peroxidase systems: a review].

    Science.gov (United States)

    Metelitsa, D I; Karaseva, E I

    2007-01-01

    The role of complexes containing oxygen or peroxide in monooxygenase systems and models thereof, as well as in peroxidase- and quasi-peroxidase-catalyzed processes, has been reviewed. Pathways of conversion of these intermediate complexes involving single-electron (radical) and two-electron (heterolytic) mechanisms are dealt with. Coupled peroxidase-catalyzed oxidation of aromatic amines and phenols is analyzed; inhibition and activation of peroxidase-catalyzed reactions are characterized quantitatively. Oxidation of chromogenic substrates (ABTS, OPD, and TMB) in the presence of phenolic inhibitors or polydisulfides of substituted phenols is characterized by inhibition constants (Ki, micromol). Activation of peroxidase-catalyzed oxidation of the same substrates is characterized by the degree (coefficient) of activation (alpha, M(-1)), which was determined for 2-aminothiazole, melamine, tetrazole, and its 5-substituted derivatives. Examples of applied use of peroxidase-catalyzed enzyme and model systems are given (oxidation of organic compounds, chemical analysis, enzyme immunoassay, tests for antioxidant activity of biological fluids).

  3. Free radical-scavenging capacity, antioxidant activity and phenolic content of Pouzolzia zeylanica

    Directory of Open Access Journals (Sweden)

    PEIYUAN LI

    2011-05-01

    Full Text Available Pouzolzia zeylanica was extracted with different solvents (acetone, ethyl acetate and petroleum ether, using different protocols (cold-extraction and Soxhlet extraction. To evaluate the antiradical and antioxidant abilities of the extracts, four in vitro test systems were employed, i.e., DPPH, ABTS and hydroxyl radical scavenging assays and a reducing power assay. All extracts exhibited outstanding antioxidant activities that were superior to that of butylated hydroxytoluene. The ethyl acetate extracts exhibited the most significant antioxidant activities, and cold-extraction under stirring seemed to be the more efficacious method for acquiring the predominant antioxidants. Furthermore, the antioxidant activities and total phenolic (TP content of different extracts followed the same order, i.e., there is a good correlation between antioxidant activities and TP content. The results showed that these extracts, especially the ethyl acetate extracts, could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.

  4. Enhancement by catechols of hydroxyl-radical formation in the presence of ferric ions and hydrogen peroxide.

    Science.gov (United States)

    Iwahashi, H; Morishita, H; Ishii, T; Sugata, R; Kido, R

    1989-03-01

    The effect of caffeic acid, a kind of catechol, on the Fenton reaction was examined by using the ESR spin trapping technique. Caffeic acid enhanced the formation of hydroxyl radicals in the reaction mixture, which contained caffeic acid, hydrogen peroxide, ferric chloride, EDTA, and potassium phosphate buffer. Chlorogenic acid, which is an ester of caffeic acid with quinic acid, also stimulated the formation of the hydroxyl radicals. Quinic acid did not stimulate the reaction, suggesting that the catechol moiety in chlorogenic acid is essential to the enhancement of the hydroxyl-radical formation. Indeed, other catechols and related compounds such as pyrocatechol, gallic acid, dopamine, and noradrenaline effectively stimulated the formation of the hydroxyl radicals. The above results confirm the idea that the catechol moiety is essential to the enhancement. Ferulic acid, 4-hydroxy-3-methoxybenzoic acid, and salicylic acid had no effect on the formation of the hydroxyl radicals. The results indicate that the enhancement by the catechols of the formation of hydroxyl radicals is diminished if a methyl ester is formed at the position of the hydroxyl group of the catechol. In the absence of iron chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP, formation of hydroxyl radicals was not detected, suggesting that chelators are essential to the reaction. The enhancement of the formation of hydroxyl radicals is presumably due to the reduction of ferric ions by the catechols. Thus, the catechols may exert deleterious effects on biological systems if chelators such as EDTA, DETAPAC, desferrioxamine, citrate, and ADP are present.

  5. Bursectomy at radical gastrectomy

    Institute of Scientific and Technical Information of China (English)

    Cuneyt; Kayaalp

    2015-01-01

    Radical gastrectomy with extended lymph node dissec tion and prophylactic resection of the omentum, peri toneum over the posterior lesser sac, pancreas and/o spleen was advocated at the beginning of the 1960 s in Japan. In time, prophylactic routine resections of the pancreas and/or spleen were abandoned because of the high incidence of postoperative complications. However omentectomy and bursectomy continued to be standard parts of traditional radical gastrectomy. The bursaomentalis was thought to be a natural barrier against invasion of cancer cells into the posterior part of the stomach. The theoretical rationale for bursectomy was to reduce the risk of peritoneal recurrences by eliminating the peritoneum over the lesser sac, which might include free cancer cells or micrometastases. Over time, the indication for bursectomy was gradually reduced to only patients with posterior gastric wall tumors penetrating the serosa. Despite its theoretical advantages, its benefit for recurrence or survival has not been proven yet. The possible reasons for this inconsistency are discussed in this review. In conclusion, the value of bursectomy in the treatment of gastric cancer is still under debate and large-scale randomized studies are necessary. Until clear evidence of patient benefit is obtained, its routine use cannot be recommended.

  6. Radically innovative steelmaking technologies

    Science.gov (United States)

    Szekely, Julian

    1980-09-01

    The steel industry is faced with serious problems caused by the increasing cost of energy, labor and capital and by tough overseas competition, employing new highly efficient process plants. The very high cost of capital and of capital equipment renders the construction of new green field site plants, exemplifying the best available technology economically unattractive. For this reason, over the long term the development radically innovative steelmaking technologies appears to be the only satisfactory resolution of this dilemma. The purpose of this article is to present a critical review of some of the radically innovative steelmaking technologies that have been proposed during the past few years and to develop the argument that these indeed do deserve serious consideration at the present time. It should be stressed, however, that these innovative technologies can be implemented only as part of a carefully conceived long range plan, which contains as a subset short term solutions, such as trigger prices improved investment credits, and so forth and intermediate term solutions, such as more extensive use of continuous casting, external desulfurization and selective modernization in general.

  7. ABT-431: the diacetyl prodrug of A-86929, a potent and selective dopamine D1 receptor agonist: in vitro characterization and effects in animal models of Parkinson's disease.

    Science.gov (United States)

    Shiosaki, K; Jenner, P; Asin, K E; Britton, D R; Lin, C W; Michaelides, M; Smith, L; Bianchi, B; Didomenico, S; Hodges, L; Hong, Y; Mahan, L; Mikusa, J; Miller, T; Nikkel, A; Stashko, M; Witte, D; Williams, M

    1996-01-01

    (-)-Trans 9,10-hydroxy-2-propyl-4,5,5a,6,7,11b-hexahydro-3-thia-5- azacyclopent-1-ena[c]phenanthrene hydrochloride (A-86929) is a potent and selective full agonist at the dopamine (DA) D1-like receptor. Judging by its binding affinities to the D1 and D2 classes of receptors, the compound is approximately 20-fold D1 receptor-selective, whereas relative potencies based on functional in vitro assays indicate that A-86929 is greater than 400-fold D1-selective. A-86929 has moderate to weak (Ki > 1 microM) affinity at other monoaminergic and peptidergic receptors, at ion channels and at monoamine uptake sites. The catechol of A-86929 was bis-acetylated to produce the prodrug, (-)-trans 9,10-acetoxy-2-propyl-4,5,5a,6,7,11-b-hexahydro-3-thia- 5-azacyclopent-1-ena[c]phenanthrene hydrochloride (ABT-431), which is more chemically stable yet is rapidly converted to the parent compound with a half-life of less than 1 min in plasma. Both A-86929 and ABT-431 produced contralateral rotation in rats bearing unilateral 6-hydroxydopamine lesions, with ED50 values of 0.24 mumol/kg s.c. and 0.54 mumol/kg s.c., respectively. A-86929 and ABT-431 improved behavioral disability scores and increased locomotor activity in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned marmoset model of Parkinson's disease in a dose-dependent manner (the minimum effective dose was 0.10 mumol/kg s.c.). When administered three times daily for 30 consecutive days to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned marmosets, A-86929 significantly improved disability scores throughout the duration of the study. Current Parkinson's disease therapy includes L-dopa, which stimulates both classes of DA receptors by virtue of its conversion to DA in vivo, and direct-acting D2-selective agonists. Stimulation of the D2 receptor, which is associated with all current DA agonist-based therapies, may contribute to their dose-limiting side effects. An agent such as A-86929 (or its prodrug ABT-431), which

  8. Delivery of vanillin by poly(lactic-acid) nanoparticles: Development, characterization and in vitro evaluation of antioxidant activity.

    Science.gov (United States)

    Dalmolin, Luciana Facco; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

    2016-05-01

    Poly(lactic acid) (PLA) nanoparticles containing vanillin were prepared using an emulsion-solvent evaporation technique and were characterized and assessed for their in vitro antioxidant potential. Physicochemical properties of the nanoparticles were characterized by size, polydispersity index, zeta potential, encapsulation efficiency and stability. Solid state and thermal properties were assessed using X-ray diffraction and differential scanning calorimetry, while in vitro drug release profile was also evaluated. Results showed PLA nanoparticles having a characteristic amorphous structure, sizes in the range of 240 nm with high homogeneity in size distribution, zeta potential of -22 mV and vanillin encapsulation efficiency of 41%. In vitro release study showed a slow and sustained release of vanillin governed by diffusion. Nanoparticles were stable over a period of three months. Antioxidant ability of the vanillin-loaded PLA nanoparticles in scavenging the radical 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was inferior to free vanillin and due to its prolonged release showed a profile that was both time and concentration dependent, while free vanillin showed concentration-dependent activity. The study concluded that PLA nanoparticles are potential carriers for vanillin delivery.

  9. Reactions of the radical cations of methylated benzene derivatives in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Sehested, K.; Holcman, J.

    1978-03-23

    The radical cations of methylated benzene decompose in acid solution into the corresponding methylbenzyl radical and a proton. The rate constant for this reaction decreases by three orders of magnitude as the number of methyl groups increases from one to five. The rate constants can be correlated with the ionization potential of the parent compound. In neutral solution the reverse reaction to the acid-catalyzed OH adduct conversion occurs and the radical cations react with water to form the OH adduct. In slightly alkaline solution the radical cations of the higher methylated benzenes (n greater than or equal to 3) react with hydroxide ions forming the OH adduct.

  10. Observation of OH radicals produced by pulsed discharges on the surface of a liquid

    Science.gov (United States)

    Kanazawa, Seiji; Kawano, Hirokazu; Watanabe, Satoshi; Furuki, Takashi; Akamine, Shuichi; Ichiki, Ryuta; Ohkubo, Toshikazu; Kocik, Marek; Mizeraczyk, Jerzy

    2011-06-01

    The hydroxyl radical (OH) plays an important role in plasma chemistry at atmospheric pressure. OH radicals have a higher oxidation potential compared with other oxidative species such as free radical O, atomic oxygen, hydroperoxyl radical (HO2), hydrogen peroxide(H2O2) and ozone. In this study, surface discharges on liquids (water and its solutions) were investigated experimentally. A pulsed streamer discharge was generated on the liquid surface using a point-to-plane electrode geometry. The primary generation process of OH radicals is closely related to the streamer propagation, and the subsequent secondary process after the discharge has an influence on the chemical reaction. Taking into account the timescale of these processes, we investigated the behavior of OH radicals using two different diagnostic methods. Time evolution of the ground-state OH radicals above the liquid surface after the discharge was observed by a laser-induced fluorescence (LIF) technique. In order to observe the ground-state OH, an OH [A 2∑+(v' = 1) gas phase to the liquid surface and dissolved in the liquid. These dissolved OH radicals were measured by a chemical probe method. Terephthalic acid was used as an OH radical trap and fluorescence of the resulting 2-hydroxyterephthalic acid was measured. This paper directly presents visualization of OH radicals over the liquid surface by means of LIF, and indirectly describes OH radicals dissolved in water by means of a chemical method.

  11. Antimutagenic and free radical scavenger effects of leaf extracts from Accacia salicina

    Directory of Open Access Journals (Sweden)

    Boubaker Jihed

    2011-12-01

    Full Text Available Abstract Background Three extracts were prepared from the leaves of Accacia salicina; ethyl acetate (EA, chloroform (Chl and petroleum ether (PE extracts and was designed to examine antimutagenic, antioxidant potenty and oxidative DNA damage protecting activity. Methods Antioxidant activity of A. salicina extracts was determined by the ability of each extract to protect against plasmid DNA strand scission induced by hydroxyl radicals. An assay for the ability of these extracts to prevent mutations induced by various oxidants in Salmonella typhimurium TA102 and TA 104 strains was conducted. In addition, nonenzymatic methods were employed to evaluate anti-oxidative effects of tested extracts. Results These extracts from leaf parts of A. salicina showed no mutagenicity either with or without the metabolic enzyme preparation (S9. The highest protections against methylmethanesulfonate induced mutagenicity were observed with all extracts and especially chloroform extract. This extract exhibited the highest inhibitiory level of the Ames response induced by the indirect mutagen 2- aminoanthracene. All extracts exhibited the highest ability to protect plasmid DNA against hydroxyl radicals induced DNA damages. The ethyl acetate (EA and chloroform (Chl extracts showed with high TEAC values radical of 0.95 and 0.81 mM respectively, against the ABTS.+. Conclusion The present study revealed the antimutagenic and antioxidant potenty of plant extract from Accacia salicina leaves.

  12. Synthesis of novel well-defined poly(vinyl acetate)-b-poly(acrylonitrile) and derivatized water-soluble poly(vinyl alcohol)-b-poly(acrylic acid) block copolymers by cobalt-mediated radical polymerization

    NARCIS (Netherlands)

    Debuigne, A.; Warnant, J.; Jerome, R.; Voets, I.K.; Keizer, de A.; Cohen Stuart, M.A.; Detrembleur, C.

    2008-01-01

    Poly(vinyl acetate)¿Co(acac)2 macroinitiators, prepared by cobalt-mediated radical polymerization of vinyl acetate (VAc), were used to synthesize well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) block copolymers. Different solvents and temperatures were tested for the polymerizati

  13. 不同浓度ABT_1号生根粉对三角梅扦插繁殖的研究%Study on the Cutting Propagation of Bougainvillea spectabilis with different Concentrations of Rooting Powder of ABT No.1

    Institute of Scientific and Technical Information of China (English)

    唐海英; 唐红燕

    2011-01-01

    The effect of the different concentrations(0.0、0.1、0.5、1.0g/L) of rooting powder of ABT No.1 on rooting of cuttings propagation of Bougainvillea spectabilis with half lignification cuttings was studied.The result showed that the concentrations of the 1.0g/L was the best for the rooting of Bougainvillea spectabilis,and the percentage of rooting was 89.4%.%通过试验研究外源激素ABT1号4种不同浓度(0.0、0.1、0.5、1.0g/L)对三角梅半木质化穗条生根率的影响,试验采用单因素设计,基质用山地红壤。结果表明:采用ABT11.0g/L浓度处理三角梅插穗促进生根效果较好,生根率可达89.4%。

  14. Radicals in Berkeley?

    Science.gov (United States)

    Linn, Stuart

    2015-04-03

    In a previous autobiographical sketch for DNA Repair (Linn, S. (2012) Life in the serendipitous lane: excitement and gratification in studying DNA repair. DNA Repair 11, 595-605), I wrote about my involvement in research on mechanisms of DNA repair. In this Reflections, I look back at how I became interested in free radical chemistry and biology and outline some of our bizarre (at the time) observations. Of course, these studies could never have succeeded without the exceptional aid of my mentors: my teachers; the undergraduate and graduate students, postdoctoral fellows, and senior lab visitors in my laboratory; and my faculty and staff colleagues here at Berkeley. I am so indebted to each and every one of these individuals for their efforts to overcome my ignorance and set me on the straight and narrow path to success in research. I regret that I cannot mention and thank each of these mentors individually.

  15. [Research progress on free radicals in human body].

    Science.gov (United States)

    Wang, Q B; Xu, F P; Wei, C X; Peng, J; Dong, X D

    2016-08-10

    Free radicals are the intermediates of metabolism, widely exist in the human bodies. Under normal circumstances, the free radicals play an important role in the metabolic process on human body, cell signal pathway, gene regulation, induction of cell proliferation and apoptosis, so as to maintain the normal growth and development of human body and to inhibit the growth of bacteria, virus and cancer. However, when organic lesion occurs affected by external factors or when equilibrium of the free radicals is tipped in the human body, the free radicals will respond integratedly with lipids, protein or nucleic acid which may jeopardize the health of human bodies. This paper summarizes the research progress of the free radicals conducted in recent years, in relations to the perspective of the types, origins, test methods of the free radicals and their relationship with human's health. In addition, the possible mechanisms of environmental pollutants (such as polycyclic aromatic hydrocarbons) mediating oxidative stress and free radicals scavenging in the body were also summarized.

  16. Chlorogenic acid loaded chitosan nanoparticles with sustained release property, retained antioxidant activity and enhanced bioavailability

    Directory of Open Access Journals (Sweden)

    Ilaiyaraja Nallamuthu

    2015-06-01

    Full Text Available In this study, chlorogenic acid (CGA, a phenolic compound widely distributed in fruits and vegetables, was encapsulated into chitosan nanoparticles by ionic gelation method. The particles exhibited the size and zeta potential of 210 nm and 33 mV respectively. A regular, spherical shaped distribution of nanoparticles was observed through scanning electron microscopy (SEM and the success of entrapment was confirmed by FTIR analysis. The encapsulation efficiency of CGA was at about 59% with the loading efficiency of 5.2%. In vitro ABTS assay indicated that the radical scavenging activity of CAG was retained in the nanostructure and further, the release kinetics study revealed the burst release of 69% CGA from nanoparticles at the end of 100th hours. Pharmacokinetic analysis in rats showed a lower level of Cmax, longer Tmax, longer MRT, larger AUC0–t and AUC0–∞ for the CGA nanoparticles compared to free CGA. Collectively, these results suggest that the synthesised nanoparticle with sustained release property can therefore ease the fortification of food-matrices targeted for health benefits through effective delivery of CGA in body.

  17. Isolation and Bioactivity Analysis of Ethyl Acetate Extract from Acer tegmentosum Using In Vitro Assay and On-Line Screening HPLC-ABTS+ System

    Directory of Open Access Journals (Sweden)

    Kwang Jin Lee

    2014-01-01

    Full Text Available The Acer tegmentosum (3 kg was extracted using hot water, and the freeze-dried extract powder was partitioned successively using dichloromethane (DCM, ethyl acetate (EA, butyl alcohol (n-BuOH, and water. From the EA extract fraction (1.24 g, five phenolic compounds were isolated by the silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatography. Based on spectroscopic methods such as 1H-NMR, 13C-NMR, and LC/MS the chemical structures of the compounds were confirmed as feniculin (1, avicularin (2, (+-catechin (3, (−-epicatechin (4, and 6′-O-galloyl salidroside (5. Moreover, a rapid on-line screening HPLC-ABTS+ system for individual bioactivity of the EA-soluble fraction (five phenolic compounds was developed. The results indicated that compounds 1 and 2 were first isolated from the A. tegmentosum. The anti-inflammatory activities and on-line screening HPLC-ABTS+ assay method of these compounds in LPS-stimulated murine macrophages were rapid and efficient for the investigation of bioactivity of A. tegmentosum.

  18. Radical chic? Yes we are!

    OpenAIRE

    Hartle, J.F.

    2012-01-01

    Ever since Tom Wolfe in a classical 1970 essay coined the term "radical chic", upper-class flirtation with radical causes has been ridiculed. But by separating aesthetics from politics Wolfe was actually more reactionary than the people he criticized, writes Johan Frederik Hartle.

  19. Muoniated acyl and thioacyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, Iain [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Brodovitch, Jean-Claude [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Ghandi, Khashayar [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Percival, Paul W. [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada)]. E-mail: percival@sfu.ca

    2006-03-31

    The product of the reaction of muonium with tert-butylisocyanate was previously assigned as the muoniated tert-butylaminyl radical (I. McKenzie, J.-C. Brodovitch, K. Ghandi, S. Kecman, P. W. Percival, Physica B 326 (2003) 76). This assignment is incorrect since the muon and {sup 14}N hyperfine-coupling constants (hfcc) of this radical would have the opposite sign, which is in conflict with the experimental results. The radical is now reassigned as the muoniated N-tert-butylcarbamoyl radical, based on the similarities between the experimental muon and {sup 14}N hfcc and hfcc calculated at the UB3LYP/6-311G(d,p)//UB3LYP/EPR-III level. The large zero-point energy in the N-Mu bond results in the dissociation barrier of the muoniated N-tert-butylcarbamoyl radical being above the combined energy of the reactants, in contrast to the N-tert-butylcarbamoyl radical where the dissociation barrier lies below the combined energy of the reactants. The reaction of muonium with tert-butylisothiocyanate produced both conformers of the muoniated N-tert-butylthiocarbamoyl radical and their assignment was based on the similarities between the experimental and calculated muon hfcc. These are the first acyl and thioacyl radicals to be directly detected by muon spin spectroscopy.

  20. Time-resolved CIDNP: an NMR way to determine the EPR parameters of elusive radicals.

    Science.gov (United States)

    Morozova, Olga B; Ivanov, Konstantin L; Kiryutin, Alexey S; Sagdeev, Renad Z; Köchling, Talea; Vieth, Hans-Martin; Yurkovskaya, Alexandra V

    2011-04-14

    Chemically Induced Dynamic Nuclear Polarization (CIDNP) of the diamagnetic products of radical reactions is exploited for the purpose of determination of the hyperfine coupling constants (HFCCs) of the radical intermediates. A simple proportionality relation between geminate CIDNP of a nucleus and its HFCC at the radical stage is established. The applicability range of this relation is determined: the relation is fulfilled in the case of a large difference in g-factor between the radicals involved and for the situation where the number of magnetic nuclei in the system is sufficiently large. The validity of the relation was confirmed by CIDNP experiments on radical pairs with precisely known HFCCs. Using the proportionality relation we were able to measure the HFCCs in various short-lived radicals of the amino acids histidine and tryptophan and of the S-N-centered cyclic radical of methionine derived from the methionine-glycine dipeptide in aqueous solution.

  1. Pulse radiolysis studies of aminobenzenesulfonates: Formation of cation radicals. [7 MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Behar, D.; Behar, B. (Univ. of Notre Dame, IN (United States))

    1991-09-19

    Sulfanilic acid and anilinedisulfonic acids (ADS) react with OH radicals (k = 8.2 {times} 10{sup 9} and 5.9 {times} 10{sup 9} M{sup {minus}1}s{sup {minus}1}) to form the corresponding OH adducts. In acid solutions the adducts react with protons to yield cation radicals (k = 5.3 {times} 10{sup 8} and 8.7 {times} 10{sup 8} M{sup {minus}1}s{sup {minus}1}). N{sub 3} oxidizes sulfanilic acid directly to the cation radical by an electron-transfer reaction at a diffusion-controlled rate constant, k = 6.5 {times} 10{sup 9}M{sup {minus}1}s{sup {minus}1}, while the rate of oxidation of ADS by N{sub 3} is only 7.6 {times} 10{sup 7} M{sup {minus}1}s{sup {minus}1}. SO{sub 4}{sup {minus}} on the other hand oxidizes ADS to the cation radical at a rate of 1.8 {times} 10{sup 9}M{sup {minus}1}s{sup {minus}1}. Both cation radicals deprotonate to the anilino-type radicals in acid-base equilibria. The pK{sub a} of deprotonation of the sulfanilic cation radical is 5.8 {plus minus} 0.05 and that of the ADS cation radical is 4.3 {plus minus} 0.05.

  2. Radicals in {gamma}-irradiated wool

    Energy Technology Data Exchange (ETDEWEB)

    Baeva, N.N.; Sadova, S.F.; Sharpatyi, V.A.

    1992-01-01

    Radicals were identified in wool fiber {gamma}-irradiated at 77 K by EPR: products of reaction of an electron e and H atom with amino acid residues and a polypeptide chain, and their partial yields at 77 K and the reactivity scale of e with respect to the individual fragments of the protein molecule were determined: [RSSR]: [>C=O{sub p.b.}]:[NH{sub 3}{sup +}-R]:[aromatic ring] = 4:3: > 1:1. 10 refs., 1 fig., 1 tab.

  3. Removal of NOx by radical injection

    Institute of Scientific and Technical Information of China (English)

    LIN He; GAO Xiang; LUO Zhongyang; CEN Kefa; PEI Meixiang; HUANG Zhen

    2004-01-01

    Removal of NOx ( DeNOx, NOx is the total of NO and NO2) from flue gas by radical injection has been investigated . The discharge characteristics were examined and the steady streamer corona was acquired by adjusting the nozzle gases properly. It was found that an increase in the voltage resulted in a decrease in the NO concentration and the concentration of the NO2 increased at low voltages but decreased as the voltage rose to a certain level. The DeNOx efficiency increased as the applied voltage rose and reached a maximum of 70% when the voltage approached the breakdown voltage. The hypothetical mechanism of NOx removal suggested that the radicals formed in the discharge process converted the NO and NO2 into acidic species. The Monte Carlo method was used to calculate the rate coefficients and the productivity of the radicals, and then the concentrations of both NO and NO2 and the DeNOx efficiencies were calculated with chemical kinetics. The calculated DeNOx efficiencies were comparable with the experimental DeNOx efficiencies at low voltages, but were lower at high voltages.

  4. Detection of hydroxyl radical in plasma reaction on toluene removal

    Institute of Scientific and Technical Information of China (English)

    GUO Yufang; LIAO Xiaobin; YE Daiqi

    2008-01-01

    A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge (DBD) reaction. A film, which was impregnated with salicylic acid, was used to detect OH radical in plasma reaction at room temperature and atmospheric pressure. Salicylic acid reacts with OH radical and produces 2,5-dihydroxybenzoic acid (2,5-DHBA). Then, a high performance liquid chromatography (HPLC) was carded out to detect the concentration of 2,5-DHBA. Therefore, OH radical in nonthermal plasma reaction could be calculated. In this plasma reaction, the applied voltage was controlled at 10 kV, the initial concentration of toluene was 400 mg/m3, and the gas flow rate was 300 ml/min. It was observed that when the film was placed away from the plasma area, 2,5-DHBA could not be detected by HPLC, although the sampling thne lasted for 48 h. On the other hand, when the film was placed in the plasma area and the sampling time being too long ( 4 h), the concentration of 2,5-DHBA was also below detection limit, and it could not be detected by HPLC. However, when the fihn was placed in the plasma reaction field with the sampling time being 3 h, the concentration of OH radical was calculated to be 10.54 × 1012 cm-3. In addition, concentration of OH radical was investigated under different humidity, such as 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%. The results showed that the amount of OH radical stayed at order of magnitude of 1012 cm-3 and increased with the increase of humidity.

  5. Free radical scavenging activity of leaves of Cucumis sativus

    Directory of Open Access Journals (Sweden)

    Pritesh Rashmikant Shah

    2013-11-01

    Full Text Available Cucumis sativus commonly called as ‘Cucumber’ is commonly used plant throughout the world. The plant is attributed to various uses in Ayurveda. The methanolic extract of leaves of Cucumis sativus was screened for free radical scavenging activity properties using gallic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH free radical. Different concentrations of leaf extract ranging from 100- 1000µg/ml were subjected to DPPH assay. Leaf extract showed a maximum DPPH scavenging activity of 86.17% at 1000µg/ml, whereas for Gallic acid it was found to be 98.03%. The study reveals that antioxidant activity of plant would exert beneficial effects if consumed.

  6. Radical Scavenging Efficacy of Thiol Capped Silver Nanoparticles

    Indian Academy of Sciences (India)

    Kumudini Chandraker; Sandeep Kumar Vaishanav; Rekha Nagwanshi; Manmohan L Satnami

    2015-12-01

    Radical scavenging efficacy of L-cysteine (L-Cys), glutathione (GSH) and thioctic acid (TA) in the presence of silver nanoparticles (AgNPs) were determined by 1,1-diphenyl 2-picryl hydrazil (DPPH), nitric oxide (NO) and hydroxyl (OH) radicals as spectrophotometric assay. The hydrogen peroxide (H2O2) scavenging efficacy has been determined by titration method. Ascorbic acid has been used as standard for all radical scavenging efficacies. In general, antioxidant activity decreases in the presence of AgNPs. The covalent interactions of thiols (-SH) were found to be a key factor for the decreases in scavenging activity. The effect of thiol concentrations has been discussed. The size and shape of the nanoparticles and AgNP-SR interactions have been characterized through Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) spectroscopy, respectively.

  7. The acid-catalyzed rearrangement CH3Oo --> oCH2OH and its involvement in the dissociation of the methanol dimer radical cation; A Quid pro Quo reaction

    NARCIS (Netherlands)

    Burgers, P.C.; Ruttink, P.J.A.

    2005-01-01

    The barrier for the radical isomerization CH3Oo --> oCH2OH is calculated by CBS-QB3 to be 29.7 kcal mol-1 and lies higher (by 5.7 kcal mol-1) than the dissociation limit CH2O+Ho. Hence, CH3Oo does not isomerize to the more stable oCH2OH on its own. However, this barrier is reduced to 15.8 kcal mol-1

  8. Free radicals and male reproduction.

    Science.gov (United States)

    Agarwal, Ashok; Allamaneni, Shyam S R

    2011-03-01

    Male factor accounts for almost 50% cases of infertility. The exact mechanism of sperm dysfunction is not known in many cases. Extensive research in the last decade has led to the identification of free radicals (reactive oxygen species) as mediators of sperm dysfunction in both specific diagnoses and idiopathic cases of male infertility. Elevated levels of reactive oxygen species are seen in up to 30-80% of men with male infertility. The role of free radicals has been studied extensively in the process of human reproduction. We know now that a certain level of free radicals is necessary for normal sperm function, whereas an excessive level of free radicals can cause detrimental effect on sperm function and subsequent fertilisation and offspring health. Oxidative stress develops when there is an imbalance between generation of free radicals and scavenging capacity of anti-oxidants in reproductive tract. Oxidative stress has been shown to affect both standard semen parameters and fertilising capacity. In addition, high levels of free radicals have been associated with lack of or poor fertility outcome after natural conception or assisted reproduction. Diagnostic techniques to quantify free radicals in infertile patients can assist physicians treating patients with infertility to plan for proper treatment strategies. In vivo anti-oxidants can be used against oxidative stress in male reproductive tract. Supplementation of in vitro anti-oxidants can help prevent the oxidative stress during sperm preparation techniques in assisted reproduction.

  9. Cloning and characterization of a new laccase from Bacillus licheniformis catalyzing dimerization of phenolic acids.

    Science.gov (United States)

    Koschorreck, Katja; Richter, Sven M; Ene, Augusta B; Roduner, Emil; Schmid, Rolf D; Urlacher, Vlada B

    2008-05-01

    A new laccase gene (cotA) was cloned from Bacillus licheniformis and expressed in Escherichia coli. The recombinant protein CotA was purified and showed spectroscopic properties, typical for blue multi-copper oxidases. The enzyme has a molecular weight of approximately 65 kDa and demonstrates activity towards canonical laccase substrates 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), syringaldazine (SGZ) and 2,6-dimethoxyphenol (2,6-DMP). Kinetic constants KM and kcat for ABTS were of 6.5+/-0.2 microM and 83 s(-1), for SGZ of 4.3+/-0.2 microM and 100 s(-1), and for 2,6-DMP of 56.7+/-1.0 microM and 28 s(-1). Highest oxidizing activity towards ABTS was obtained at 85 degrees C. However, after 1 h incubation of CotA at 70 degrees C and 80 degrees C, a residual activity of 43% and 8%, respectively, was measured. Furthermore, oxidation of several phenolic acids and one non-phenolic acid by CotA was investigated. CotA failed to oxidize coumaric acid, cinnamic acid, and vanillic acid, while syringic acid was oxidized to 2,6-dimethoxy-1,4-benzoquinone. Additionally, dimerization of sinapic acid, caffeic acid, and ferulic acid by CotA was observed, and highest activity of CotA was found towards sinapic acid.

  10. Guest Editorial: Processes of Radicalization and De-Radicalization

    Directory of Open Access Journals (Sweden)

    Donatella Della Porta

    2012-05-01

    Full Text Available The study of radicalization and de-radicalization, understood as processes leading towards the increased or decreased use of political violence, is central to the question of how political violence emerges, how it can be prevented, and how it can be contained. The focus section of this issue of the International Journal of Conflict and Violence addresses radicalization and de-radicalization, seeking to develop a more comprehensive understanding of the processes, dynamics, and mechanisms involved and taking an interdisciplinary approach to overcome the fragmentation into separate disciplines and focus areas. Contributions by Pénélope Larzillière, Felix Heiduk, Bill Kissane, Hank Johnston, Christian Davenport and Cyanne Loyle, Veronique Dudouet, and Lasse Lindekilde address repressive settings, legitimacy, institutional aspects, organizational outcomes, and dynamics in Europe, Asia, Africa, and North and South America.

  11. Generation and characterization of ABT-981, a dual variable domain immunoglobulin (DVD-Ig(TM)) molecule that specifically and potently neutralizes both IL-1α and IL-1β.

    Science.gov (United States)

    Lacy, Susan E; Wu, Chengbin; Ambrosi, Dominic J; Hsieh, Chung-Ming; Bose, Sahana; Miller, Renee; Conlon, Donna M; Tarcsa, Edit; Chari, Ravi; Ghayur, Tariq; Kamath, Rajesh V

    2015-01-01

    Interleukin-1 (IL-1) cytokines such as IL-1α, IL-1β, and IL-1Ra contribute to immune regulation and inflammatory processes by exerting a wide range of cellular responses, including expression of cytokines and chemokines, matrix metalloproteinases, and nitric oxide synthetase. IL-1α and IL-1β bind to IL-1R1 complexed to the IL-1 receptor accessory protein and induce similar physiological effects. Preclinical and clinical studies provide significant evidence for the role of IL-1 in the pathogenesis of osteoarthritis (OA), including cartilage degradation, bone sclerosis, and synovial proliferation. Here, we describe the generation and characterization of ABT-981, a dual variable domain immunoglobulin (DVD-Ig) of the IgG1/k subtype that specifically and potently neutralizes IL-1α and IL-1β. In ABT-981, the IL-1β variable domain resides in the outer domain of the DVD-Ig, whereas the IL-1α variable domain is located in the inner position. ABT-981 specifically binds to IL-1α and IL-1β, and is physically capable of binding 2 human IL-1α and 2 human IL-1β molecules simultaneously. Single-dose intravenous and subcutaneous pharmacokinetics studies indicate that ABT-981 has a half-life of 8.0 to 10.4 d in cynomolgus monkey and 10.0 to 20.3 d in rodents. ABT-981 exhibits suitable drug-like-properties including affinity, potency, specificity, half-life, and stability for evaluation in human clinical trials. ABT-981 offers an exciting new approach for the treatment of OA, potentially addressing both disease modification and symptom relief as a disease-modifying OA drug.

  12. Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris Leaves

    NARCIS (Netherlands)

    Dapkevicius, A.; Beek, van T.A.; Lelyveld, G.P.; Veldhuizen, van A.; Groot, de Æ.; Linssen, J.P.H.; Venskutonis, R.

    2002-01-01

    2,2-Diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity-guided fractionation of a leaf extract of Thymus vulgaris led to the isolation of the radical scavengers rosmarinic acid 1, eriodictyol, taxifolin, luteolin 7-glucuronide, p-cymene 2,3-diol, p-cymene 2,3-diol 6-6'-dimer, carvacrol, th

  13. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2014-07-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  14. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2013-01-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  15. Measurements of hydroxyl and hydroperoxy radicals during CalNex-LA: Model comparisons and radical budgets

    Science.gov (United States)

    Griffith, S. M.; Hansen, R. F.; Dusanter, S.; Michoud, V.; Gilman, J. B.; Kuster, W. C.; Veres, P. R.; Graus, M.; Gouw, J. A.; Roberts, J.; Young, C.; Washenfelder, R.; Brown, S. S.; Thalman, R.; Waxman, E.; Volkamer, R.; Tsai, C.; Stutz, J.; Flynn, J. H.; Grossberg, N.; Lefer, B.; Alvarez, S. L.; Rappenglueck, B.; Mielke, L. H.; Osthoff, H. D.; Stevens, P. S.

    2016-04-01

    Measurements of hydroxyl (OH) and hydroperoxy (HO2*) radical concentrations were made at the Pasadena ground site during the CalNex-LA 2010 campaign using the laser-induced fluorescence-fluorescence assay by gas expansion technique. The measured concentrations of OH and HO2* exhibited a distinct weekend effect, with higher radical concentrations observed on the weekends corresponding to lower levels of nitrogen oxides (NOx). The radical measurements were compared to results from a zero-dimensional model using the Regional Atmospheric Chemical Mechanism-2 constrained by NOx and other measured trace gases. The chemical model overpredicted measured OH concentrations during the weekends by a factor of approximately 1.4 ± 0.3 (1σ), but the agreement was better during the weekdays (ratio of 1.0 ± 0.2). Model predicted HO2* concentrations underpredicted by a factor of 1.3 ± 0.2 on the weekends, while measured weekday concentrations were underpredicted by a factor of 3.0 ± 0.5. However, increasing the modeled OH reactivity to match the measured total OH reactivity improved the overall agreement for both OH and HO2* on all days. A radical budget analysis suggests that photolysis of carbonyls and formaldehyde together accounted for approximately 40% of radical initiation with photolysis of nitrous acid accounting for 30% at the measurement height and ozone photolysis contributing less than 20%. An analysis of the ozone production sensitivity reveals that during the week, ozone production was limited by volatile organic compounds throughout the day during the campaign but NOx limited during the afternoon on the weekends.

  16. Penile rehabilitation after radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Ohl, Dana A; Ralph, David;

    2013-01-01

    The pathophysiology of erectile dysfunction after radical prostatectomy (RP) is believed to include neuropraxia, which leads to temporarily reduced oxygenation and subsequent structural changes in penile tissue. This results in veno-occlusive dysfunction, therefore, penile rehabilitation programm...

  17. Redox Properties of Free Radicals.

    Science.gov (United States)

    Neta, P.

    1981-01-01

    Describes pulse radiolysis as a useful means in studing one-electron redox potentials. This method allows the production of radicals and the determination of their concentration and rates of reaction. (CS)

  18. Design and synthesis of novel 3-substituted-indole derivatives as selective H3 receptor antagonists and potent free radical scavengers.

    Science.gov (United States)

    Tang, Li; Zhao, Liying; Hong, Lingjuan; Yang, Fenyan; Sheng, Rong; Chen, Jianzhong; Shi, Ying; Zhou, Naimin; Hu, Yongzhou

    2013-10-01

    A series of novel 3-substituted-indole derivatives with a benzyl tertiary amino moiety were designed, synthesized and evaluated as H3 receptor antagonists and free radical scavengers for Alzheimer's disease therapy. Most of these synthesized compounds exhibited moderate to potent antagonistic activities in CREs driven luciferase assay. In particular, compound 2d demonstrated the most favorable H3 receptor antagonistic activity with the IC50 value of 0.049μM. Besides, it also displayed high binding affinity to H3 receptor (Ki=4.26±2.55nM) and high selectivity over other three histamine receptors. Moreover, 2d and other two 3-substituted indole derivatives 1d and 3d exerted potent ABTS radical cation scavenging capacities similar to melatonin. Above results illustrate that 2d is an interesting lead for extensive optimization to explore new drug candidate for AD therapy.

  19. Persistent free radical ESR signals in marine bivalve tissues

    Energy Technology Data Exchange (ETDEWEB)

    Mehlorn, R.J. [California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; Mendez, A.T. [Fundacion Educativa Ana G. Mendez, Rio Piedras (Puerto Rico); Higashi, R. [California Univ., Bodega Bay, CA (United States). Bodega Marine Lab.; Fan, T. [California Univ., Davis, CA (United States)

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  20. Efficacy of golden rain tree against free radicals and H2O2-induced damage to pUC18/calf thymus DNA

    Institute of Scientific and Technical Information of China (English)

    Manish Kumar; Madhu Chandel; Neha Sharma; Subodh Kumar; Satwinderjeet Kaur

    2012-01-01

    Objective: To investigate the antioxidant and genoprotective potential of the methanol extract (METH-KP) along with its hexane fraction (HEX-KP) from the leaves of Koelreuteria paniculata (K. paniculata) Laxm. Methods: The antioxidant potential was checked using metal chelation assay, ABTS, DPPH (2,2-diphenyl-2-picryl-hydrazyl), reducing power and superoxide anion radical scavenging assay, Folin-Ciocalteu reducing capacity (FCR assay), Total flavonoid content (TFC assay) and genoprotective activity against the DNA damage induced by Fenton's reagent using pUC18/calf thymus. Results: Results showed that radical scavenging activities of the both test extract/fraction revealed a concentration-dependent antiradical activity in all the assays. In Metal chelation assay, METH-KP and HEX-KP showed 39.04% and 32.51% of scavenging at highest tested concentrations. The METH-KP exhibited IC50 of 54.54 μg/mL in ABTS, 115 μg/mL in DPPH, 110 μg/mL in reducing power and 135 μg/mL in superoxide anion radical scavenging assay while that HEX-KP was found to be very poor in radical scavenging in all the above assays. The phytochemical analysis showed good amount of phenolic and flavonoid compounds in METH-KP while the HEX-KP fraction lacks phenols. The METH-KP extract and HEX-KP fraction both showed DNA protective effect in Calf thymus/pUC18 DNA protection studies. Conclusions: The activity of METH-KP may be attributed to its polyphenolic constituents which needs further isolation of its active constituents which may lead to the development of novel drugs to combat cancer.

  1. [Use of phenylglyoxylic ketyl radicals in testing for antioxidative effects of various compounds].

    Science.gov (United States)

    Sersen, F; Vencel, T; Gáplovský, A; Anus, T

    2004-05-01

    The paper describes spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol, which takes place via radicals at ambient temperature. The primary product of the decomposition is short-living ketyl radicals of phenylglyoxalic acid, which are captured and stabilized by means of the spin trap of N-terc-butyl-alpha-phenylnitrone. The spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol served as the source of radicals for the determination of the antioxidative effect of known antioxidants: C-vitamin, E-vitamin, and selenomethionine. It was found that the above-mentioned antioxidants are effective scavengers of radicals of phenylglyoxalic acid. On the basis of these data, the method can be recommended for testing the antioxidative properties of other substances as potential antioxidants.

  2. Hydroxyl radicals form in natural sediments - effects on sedimentary organic matter

    Science.gov (United States)

    Skoog, Annelie; Alejandro Arias-Esquivel, Victor

    2010-05-01

    We show that hydroxyl radicals form at the oxic anoxic interface in marine sediments from ferrous iron reacting with hydrogen peroxide in the Fenton reaction. The aggressive nature of hydroxyl radicals makes it likely that they participate in degradation of sedimentary organic matter (SOM). We used terephthalic acid (TPA) to trap the hydroxyl radicals in sediment cores - TPA reacts with hydroxyl radicals to form the highly fluorescent product TPAOH. Results indicated formation of TPAOH at high concentrations at the oxic-anoxic interface. We also subjected SOM to hydroxyl radicals formed by the Fenton reaction, which resulted in changes in fluorescence properties and chemical composition. This is the first study showing formation of hydroxyl radicals and their effect on SOM, which is a previously unknown mechanism in the global carbon cycle.

  3. Radical scavenging and antioxidant effects of Matricaria chamomilla polyphenolic-polysaccharide conjugates.

    Science.gov (United States)

    Kolodziejczyk-Czepas, Joanna; Bijak, Michal; Saluk, Joanna; Ponczek, Michal B; Zbikowska, Halina M; Nowak, Pawel; Tsirigotis-Maniecka, Marta; Pawlaczyk, Izabela

    2015-01-01

    Matricaria chamomilla L. (MC), a member of the Asteraceae family, is one of the oldest medicinal plants, widely used worldwide for a variety of healing applications. Its recommendations, derived from both traditional and modern medicine, include numerous disorders such as inflammation, ulcers, wounds, gastrointestinal disorders, stomach ache, pharyngitis, rheumatic pain, as well as the other ailments. This work is focused on another aspect of the biological activity of chamomile polyphenolic-polysaccharide conjugates--their antioxidant properties in the protection of blood plasma components against in vitro oxidative stress. Measurements of DPPH and ABTS radical scavenging indicated considerable anti-free radical action of MC. Pre-incubation of blood plasma with MC considerably diminished the extent of ONOO(-)-induced oxidative modifications such as protein carbonyl groups, SH groups, 3-nitrotyrosine, as well as the formation of lipid hydroperoxides. The analysis of the FRAP assay result shows a considerable increase of ferric reducing ability of blood plasma in the presence of MC. The results obtained in this study indicate that polyphenolic-polysaccharide conjugates isolated from M. chamomilla substances possess antioxidant properties. The M. chamomilla macromolecular glycoconjugates may be useful in the creation of new natural-based medications or dietary supplements, helpful in the prevention and treatment of oxidative stress-mediated disorders.

  4. Characterization of polyphenolic constituents and radical scavenging ability of ripe tomato and red pepper fruits

    Directory of Open Access Journals (Sweden)

    Seun F. Akomolafe

    2015-03-01

    Full Text Available Objective: Characterization of polyphenolic contents and the inhibitory effects of aqueous extracts of ripe tomato (Lycopersicon esculentum and red pepper (Capsicum annuum fruits on the sodium nitroprusside (SNP and iron(II (Fe2+-induced lipid peroxidation in rat liver were examined in this study. Methods: Various experimental models such as the ABTS and #8226; (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid scavenging ability and ferric reducing power were used to characterize the antioxidant activity of the extracts. High-performance liquid chromatography (HPLC was used to determine the phenolic content of the extracts. Malondialdehyde (MDA was used as a measure of oxidative stress in the rat and #8217;s liver tissue. Results: The ABTS and #8226; scavenging ability and ferric reducing power of the aqueous extract of ripe red pepper were significantly higher than that of ripe tomato. Ripe red pepper and tomato fruits extracts inhibited NO and #8226; in a concentration dependent manner. Furthermore, the introduction of extracts of ripe red pepper and tomato caused a significant concentration-dependent decrease in the MDA content of the SNP and Fe2+-stressed liver homogenates. In addition, HPLC analyses of the extracts revealed the presence of different phenolic compounds. Conclusion: With respect to the results of the current study, ripe tomato and red pepper could be considered to be potential sources of natural antioxidants. [J Exp Integr Med 2015; 5(1.000: 61-67

  5. Protein and peptide alkoxyl radicals can give rise to C-terminal decarboxylation and backbone cleavage

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    1996-01-01

    when the free amino acid does not, and that hydroperoxides can be formed on both the backbone (at alpha-carbon positions) and the side chain. Decomposition of alpha-carbon hydroperoxides by Fe(II)-EDTA gives initially an alkoxyl radical via a pseudo-Fenton reaction; these radicals fragment rapidly...... with k estimated as > or = 10(7) s(-1). With N-acetyl amino acids and dipeptides beta-scission of an alkoxyl radical at the C-terminal alpha-carbon results in C-terminal decarboxylation, with release of CO2.-; the corresponding amides undergo deamidation with release of .C(O)NH2. Cyclic dipeptides...... undergo analogous reactions with cleavage of the alpha-carbon to carbonyl-carbon bond and formation of .C(O)NHR radicals. With substrates with large aliphatic side chains, radicals from side-chain hydroperoxides are also observed. C-terminal decarboxylation and backbone fragmentation are also observed...

  6. Evidence for production of oxidizing radicals by the particulate O-2-forming system from human neutrophils.

    Science.gov (United States)

    Tauber, A I; Gabig, T G; Babior, B M

    1979-04-01

    The particulate O-2-forming system from human neutrophils was found to oxidize methional and 2-keto-4-methylthiobutyric acid (KMB) to ethylene, indicating the formation by this system of strongly oxidizing radicals. Conforming this interpretation was the observation that ethylene production was inhibited by the radical scavengers benzoate, ethanol, and mannitol. Ethylene production was also sharply reduced by superoxide dismutase, implicatin O-2 as a precursor of oxidizing radicals. In our system catalase only partially inhibited ethylene generation from either methional or KMB, suggesting that oxidizing radicals are generated at least in part by the reacton of O-2 with compounds other than H2O2. We propose that in neutrophils oxidizing radicals are formed in a reaction between O-2 and a peroxide according to the following equation: O-2 + ROOH leads to RO . + OH- + O2, in which ROOH may be hydrogen peroxide, an alkyl peroxide, or an acyl peroxide (i.e., a peroxy acid).

  7. Peroxy radical partitioning during the AMMA radical intercomparison exercise

    Directory of Open Access Journals (Sweden)

    M. D. Andrés-Hernández

    2010-04-01

    Full Text Available Peroxy radicals were measured onboard two scientific aircrafts during the AMMA (African Monsoon Multidisciplinary Analysis campaign in summer 2006. This paper reports results from the flight on 16 August 2006 during which measurements of HO2 by laser induced fluorescence spectroscopy at low pressure (LIF-FAGE and total peroxy radicals (RO2*=HO2+ΣRO2, R= organic chain by two similar instruments based on the peroxy radical chemical amplification (PerCA technique were subject of a blind intercomparison. The German DLR-Falcon and the British FAAM-BAe-146 flew wing tip to wing tip for about 30 min making concurrent measurements on 2 horizontal level runs at 697 and 485 hPa over the same geographical area in Burkina Faso. A full set of supporting measurements comprising photolysis frequencies, and relevant trace gases like CO, NO, NO2, NOy, O3 and a wider range of VOCs were collected simultaneously.

    Results are discussed on the basis of the characteristics and limitations of the different instruments used. Generally, no data bias are identified and the RO2* data available agree quite reasonably within the instrumental errors. The [RO2*]/[HO2] ratios, which vary between 1:1 and 3:1, as well as the peroxy radical variability, concur with variations in photolysis rates and in other potential radical precursors. Model results provide additional information about dominant radical formation and loss processes.

  8. First examples of intramolecular addition of primary amidyl radicals to olefins

    Energy Technology Data Exchange (ETDEWEB)

    Gaudreault, P.; Drouin, C.; Lessard, J. [Sherbrooke Univ., PQ (Canada). Dept. de Chimie

    2005-07-01

    This paper presents the first examples of radical cyclization involving a primary amidyl radical and a pendant olefin. Amidyl radicals have attracted interest in terms of their structure, reactivity, and ways to generate them. The intramolecular addition of an amidyl radical on a pendant olefin appears to be a powerful synthetic tool for creating nitrogen-containing heterocycles. Although several examples of cyclization involving secondary amidyl radicals are cited in the the literature, there are no examples of a successful cyclization involving a primary amidyl radical. This is because all attempts to prepare the usual radical precursors have failed when applied to olefinic primary amides. This study reveals that N-(phenylthio) derivatives of olefinic primary amides can be easily prepared and that nitrogen heterocycles resulting from their radical cyclization can be obtained in good to very good yields. Four olefinic primary amides were chosen as models for radical cyclization of primary amidyl radicals. They were prepared from the corresponding carboxylic acids via the acid chlorides. Conversion of primary amides into suitable amidyl radical precursors was also examined. The study showed that N-(phenylthio) amides could be easily prepared by following a slightly modified protocol developed by Esker and Newcomb, by reacting the anion of the amide with phenylsulfenyl chloride. In particular, olefinic N-(phenylthio) amides were prepared and used as primary amidyl radical precursors in a reaction with a solution of 2,2'-azobis(isobutyronitrile) in catalytic quantities and tributyltin hydride in benzene. The resulting yields of cyclic products ranged from 63 to 85 per cent. The intent of the study was to demonstrate that it is no longer necessary to prepare an N-protected precursor and then remove the protecting group after cyclization. Further studies are currently underway. 10 refs., 1 tab.

  9. Standard Electrode Potentials Involving Radicals in Aqueous Solution: Inorganic Radicals

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, David A.; Huie, Robert E.; Koppenol, Willem H.; Lymar, Sergei V.; Merenyi, Gabor; Neta, Pedatsur; Ruscic, Branko; Stanbury, David M.; Steenken, Steen; Wardman, Peter

    2015-12-01

    Recommendations are made for standard potentials involving select inorganic radicals in aqueous solution at 25 °C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. The recommended data are summarized in tables of standard potentials, Gibbs energies of formation, radical pKa’s, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations

  10. The role of the acidity of N-heteroaryl sulfonamides as inhibitors of bcl-2 family protein-protein interactions.

    Science.gov (United States)

    Touré, B Barry; Miller-Moslin, Karen; Yusuff, Naeem; Perez, Lawrence; Doré, Michael; Joud, Carol; Michael, Walter; DiPietro, Lucian; van der Plas, Simon; McEwan, Michael; Lenoir, Francois; Hoe, Madelene; Karki, Rajesh; Springer, Clayton; Sullivan, John; Levine, Kymberly; Fiorilla, Catherine; Xie, Xiaoling; Kulathila, Raviraj; Herlihy, Kara; Porter, Dale; Visser, Michael

    2013-02-14

    Overexpression of the antiapoptotic members of the Bcl-2 family of proteins is commonly associated with cancer cell survival and resistance to chemotherapeutics. Here, we describe the structure-based optimization of a series of N-heteroaryl sulfonamides that demonstrate potent mechanism-based cell death. The role of the acidic nature of the sulfonamide moiety as it relates to potency, solubility, and clearance is examined. This has led to the discovery of novel heterocyclic replacements for the acylsulfonamide core of ABT-737 and ABT-263.

  11. Effect of polyene phosphorus ester acid radical choline on the expression of interleukin-6 in patients with non-alcoholic adipose hepatitis%多烯磷酯酰胆碱对非酒精性脂肪性肝炎患者白细胞介素-6的影响

    Institute of Scientific and Technical Information of China (English)

    观晓辉

    2009-01-01

    Objective To observe the change and the clinical significance of IL-6 in patients with non-alcoholic adipose hepatitis(NASH) after being treated with polyene phosphorus ester acid radical choline. Methods Eighty-four patients with NASH were divided into treatment and control groups, with 42 patients in each group. All patients were received both dietary control and life style improvement. The patients in treatment group were treated with polyene phosphorus ester acid radical choline. The patients in the control group were treated with vitaminE pills. Before treatment and after treatment 12 weeks, the changes of serum levels of ALT, AST, GGT, IL-6 were compared. Results After treatment, the serum levels of ALT, AST,GGT, IL-6 of the patients in the treatment group were marked decreased as compared with those in the control group(t=4.784,3.334,2.712,3.655,P<0.01). IL-6 was closely related to ALT, AST and GGT(β=0.658,0.598,0.634,P<0.01). Conclusion Polyene phosphorus ester acid radical choline can decrease the serum levels of IL-6 and improve liver function in patients with NASH.%目的 探讨非酒精性脂肪性肝炎(NASH)患者经多烯磷酯酰胆碱治疗后白细胞介素-6的变化及临床意义.方法 84例NASH患者完全随机分为治疗组和对照组,每组各42例.在改善生活方式、控制体重的基础上,治疗组给予多烯磷酯酰胆碱,对照组给予维生素E,治疗12周.比较两组间治疗前后血清中ALT、AST、GGT、IL-6水平的变化.结果 与对照组比较,治疗组治疗后血清ALT、AST、GGT、IL-6水平显著降低(t=4.784、3.334、2.712、3.655,P<0.01),IL-6与ALT、AST、GGT呈显著正相关(β=0.658,0.598,0.634,P<0.01).结论 多烯磷酯酰胆碱治疗可降低血清IL-6水平,促进NASH患者的肝功能改善.

  12. 多巴胺D4受体激动剂ABT-724对注意缺陷多动障碍模型大鼠行为的影响%Effect of dopamine D4 receptor agonist ABT-724 on behaviors in rat model of attention-deficit hyperactivity disorder

    Institute of Scientific and Technical Information of China (English)

    于琳; 曹爱华; 吕孝娜; 雷革非

    2011-01-01

    目的 探讨高选择性多巴胺D4受体激动剂ABT-724对注意缺陷多动障碍(ADHD)动物模型自发性高血压大鼠(SHR)的行为所产生的影响.方法 将哌甲酯(5mg/ks)及三种不同剂量的ABT-724(0.04mg/kg,0.16mg/kg,0.64mg/kg)干预SHR大鼠,并利用开场试验、Morris水迷宫、Làt迷宫对SHR大鼠进行行为学检测,观察SHR大鼠的行为.结果 哌甲酯及ABT-724干预后的SHR大鼠穿越格子数[分别为(70.67±8.59)个,(76.50±10.75)个,(79.17±10.44)个,(65.67±20.62)个]较盐水组大鼠[(130.33±11.40)个]减少,且差异有显著性(P<0.05);在Moms水迷宫中,干预后的SHR大鼠空间记忆能力[分别为(52.50±4.04)s,(52.17±2.99)s,(61±8.15)s,(53.83±9.87)s]与盐水组大鼠[(38.83±7.17)s]相比有所提高,差异有统计学意义(P<0.05);在Làt迷宫中,干预后的SHR大鼠直立次数[分别为(57.17±5.67)次,(60.83±8.28)次,(55.17±9.45)次,(65.33±9.50)次]与盐水组大鼠[(78.00±13.84)次]相比减少,差异显著(P<0.05).结论 ABT-724可改善SHR大鼠的自发活动水平、认知功能和非选择性注意力.%Objective To investigate the effects of a highly selective dopamine D4 receptor (ABT-724)on behaviors in Spontaneously hypertensive rats (SHR),a rat model of attention-deficit hyperactivity disorder (ADHD).Methods After intervention of methylphenidate(5mg/kg) and three different doses of ABT-724(0.04mg/kg,0.16mg/kg,0.64mg/kg),behaviors of SHR were verified by open-field test,Morris water maze and Làt maze.Results Number of square crossing after intervention of methylphenidate and ABT-724 in SHR( 70.67 ± 8.59,76.50 ± 10.75,79.17 ± 10.44,65.67 ± 20.62) was less than the saline control group( 130.33 ± 1 1.40) (P<0.05).During Morris water maze,SHRs(52.50 ± 4.04,52.17 ± 2.99,61 ± 8.15,53.83 ± 9.87 ) after intervention of both had a better spatial memory ability than control group(38.83 ±7.17) (P<0.05).In Làt maze,number of rearing after intervention of both in SHRs

  13. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  14. Epistemological barriers to radical behaviorism

    Science.gov (United States)

    O'Donohue, William T.; Callaghan, Glenn M.; Ruckstuhl, L. E.

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers. PMID:22478314

  15. Bioactive caffeic acid esters from Glycyrrhiza glabra.

    Science.gov (United States)

    Dey, Surajit; Deepak, Mundkinajeddu; Setty, Manjunath; D'Souza, Prashanth; Agarwal, Amit; Sangli, Gopal Krishna

    2009-01-01

    Thin layer chromatography bioautography (using DPPH spray reagent) guided fractionation of Glycyrrhiza glabra led to the isolation of two caffeic acid derivative esters, viz. eicosanyl caffeate (1) and docosyl caffeate (2). The two compounds exhibited potent elastase inhibitory activity, with IC(50) values of 0.99 microg mL(-1) and 1.4 microg mL(-1) for 1 and 2, respectively. The compounds also showed moderate antioxidant activity in DPPH and ABTS scavenging assays. The results indicate a possible role of caffeic acid derivatives, in addition to flavonoids in the anti-ulcer properties of G. glabra.

  16. Halogen radicals contribute to photooxidation in coastal and estuarine waters

    Science.gov (United States)

    Parker, Kimberly M.; Mitch, William A.

    2016-05-01

    Although halogen radicals are recognized to form as products of hydroxyl radical (•OH) scavenging by halides, their contribution to the phototransformation of marine organic compounds has received little attention. We demonstrate that, relative to freshwater conditions, seawater halides can increase photodegradation rates of domoic acid, a marine algal toxin, and dimethyl sulfide, a volatile precursor to cloud condensation nuclei, up to fivefold. Using synthetic seawater solutions, we show that the increased photodegradation is specific to dissolved organic matter (DOM) and halides, rather than other seawater salt constituents (e.g., carbonates) or photoactive species (e.g., iron and nitrate). Experiments in synthetic and natural coastal and estuarine water samples demonstrate that the halide-specific increase in photodegradation could be attributed to photochemically generated halogen radicals rather than other photoproduced reactive intermediates [e.g., excited-state triplet DOM (3DOM*), reactive oxygen species]. Computational kinetic modeling indicates that seawater halogen radical concentrations are two to three orders of magnitude greater than freshwater •OH concentrations and sufficient to account for the observed halide-specific increase in photodegradation. Dark •OH generation by gamma radiolysis demonstrates that halogen radical production via •OH scavenging by halides is insufficient to explain the observed effect. Using sensitizer models for DOM chromophores, we show that halogen radicals are formed predominantly by direct oxidation of Cl- and Br- by 3DOM*, an •OH-independent pathway. Our results indicate that halogen radicals significantly contribute to the phototransformation of algal products in coastal or estuarine surface waters.

  17. Radical democratic politics and feminism

    Directory of Open Access Journals (Sweden)

    Martínez Labrin, Soledad

    2006-05-01

    Full Text Available In the article I present a reflection around the radical democratic project proposed by Chantal Mouffe and Ernesto Laclau. Specifically, I examine the application of the project in the context of the “new social movements” and especially, of feminist movement. I state the need of drawing attention to universalism and essentialism as the main obstacles to generate a collective proposal without margins. Nevertheless, doubts remind about the possibility of building up a feminism tailored by the radical democratic project, in a stage in which the political action of such a movement is characterized by categories that are closed and crystallized

  18. Vaginal radical trachelectomy: an update.

    Science.gov (United States)

    Plante, Marie

    2008-11-01

    The vaginal radical trachelectomy has emerged as a valuable fertility-preserving treatment option for young women with early-stage disease. Cancer-related infertility is associated with feelings of depression, grief, stress, and sexual dysfunction. Data have shown that the overall oncological outcome is safe and that the obstetrical outcome is promising. In this article, we analyze the data on the vaginal radical trachelectomy published over the last 10 years in the context of what we have learned, what issues remain unclear, and what the future holds.

  19. Free radical facilitated damage of ungual keratin.

    Science.gov (United States)

    Khengar, Rajeshree H; Brown, Marc B; Turner, Rob B; Traynor, Matthew J; Holt, Katherine B; Jones, Stuart A

    2010-09-01

    Thioglycolic acid (TA) and urea hydrogen peroxide (urea H(2)O(2)) are thought to disrupt alpha-keratin disulfide links in the nail. However, optimal clinical use of these agents to improve the treatment of nail disorders is currently hindered by a lack of fundamental data to support their mechanism of action. The aim of this study was to investigate how the redox environment of ungual keratin, when manipulated by TA and urea H(2)O(2), influenced the properties of the nail barrier. Potentiometric and voltammetric measurements demonstrated that urea H(2)O(2) obeyed the Nernst equation for a proton coupled one-electron transfer redox process while TA underwent a series of redox reactions that was complicated by electrode adsorption and dimer formation. The functional studies demonstrated that nail permeability, measured through TBF penetration (38.51+/-10.94 microg/cm(2)/h) and nail swelling (244.10+/-14.99% weight increase), was greatest when relatively low concentrations of the thiolate ion were present in the applied solution. Limiting the thiolate ion to low levels in the solution retards thiolate dimerisation and generates thiyl free radicals. It appeared that this free radical generation was fundamental in facilitating the redox-mediated keratin disruption of the ungual membrane.

  20. High deuteron polarization in trityl radical doped deuterated polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li, E-mail: wang_li@dhu.edu.cn [Institut für Experimentalpysik I, Ruhr-Universität Bochum, 44780 Bochum (Germany); Physics Department, School of Science, Donghua University, Shanghai 200051 (China); Berlin, A. [Institut für Experimentalpysik I, Ruhr-Universität Bochum, 44780 Bochum (Germany); Doshita, N. [Physics Department, Faculty of Science, Yamagata University, Yamagata 990-8560 (Japan); Herick, J.; Hess, C. [Institut für Experimentalpysik I, Ruhr-Universität Bochum, 44780 Bochum (Germany); Iwata, T.; Kondo, K. [Physics Department, Faculty of Science, Yamagata University, Yamagata 990-8560 (Japan); Meyer, W.; Reicherz, G. [Institut für Experimentalpysik I, Ruhr-Universität Bochum, 44780 Bochum (Germany)

    2013-11-21

    Deuterated polystyrene for polarized solid targets has been prepared by chemical doping with the trityl radical ‘Finland D36’ (AH 110 355 deutero acid form). Thin foils doped with various radical densities have been produced using tetrahydrofuran as solvent. Dynamic nuclear polarization technique has been applied to polarize deuterons in the samples (98%-D) at the temperature range of about 1 K and magnetic fields of 2.5 T and 5.0 T. A maximum deuteron polarization of −61.5% with a build-up time of 100 min has been achieved at 5.0 T and about 500 mK at a radical density of 1.16×10{sup 19} spins/g. -- Highlights: •Deuterated polystyrene has been prepared by chemical doping with the trityl radical. •Thin foils doped with various radical densities have been produced. •Deuterons are polarized in the samples (98%-D) at about 1 K and 2.5 T and 5.0 T. •Maximum D-polarization of −61.5% with a T{sub bu} of 100 min has been achieved.

  1. Pulse radiolysis studies on reactions of hydroxyl radicals with selenocystine derivatives.

    Science.gov (United States)

    Mishra, B; Kumbhare, L B; Jain, V K; Priyadarsini, K I

    2008-04-10

    Reactions of hydroxyl radicals (*OH) with selenocystine (SeCys) and two of its analogues, diselenodipropionic acid (SeP) and selenocystamine (SeA), have been studied in aqueous solutions at pHs of 1, 7, and 10 using the pulse radiolysis technique coupled with absorption detection. All of these diselenides react with *OH radicals with rate constants of approximately 10(10) M(-1) s(-1), producing diselenide radical cations ( approximately 1-5 micros after the pulse), with an absorption maximum at 560 nm, by elimination of H(2)O or OH(-) from hydroxyl radical adducts. Assignment of the 560 nm band to the diselenide radical cation was made by comparing the transient spectra with those produced upon reaction of diselenides with specific one-electron oxidants, Cl(2)(*-) (pH 1) and Br(2)(*-) radicals (pHs of 7 and 10). SeP having a carboxylic acid functionality showed quantitative conversion of hydroxyl radical adducts to radical cations. The compounds SeCys and SeA, having an amino functional group, in addition to the radical cations, produced a new transient with lambda(max) at 460 nm, at later time scales ( approximately 20-40 micros after the pulse). The rate and yield of formation of the 460 nm band increased with increasing concentrations of either SeCys or SeA. In analogy with similar studies reported for analogous disulfides, the 460 nm transient absorption band has been assigned to a triselenide radical adduct. The one-electron reduction potentials of the compounds were estimated to be 0.96, 1.3, and 1.6 V versus NHE, respectively, for SeP, SeCys, and SeA at pH 7. From these studies, it has been concluded that the electron-donating carboxylic acid group decreases the reduction potential and facilitates quantitative conversion of hydroxyl radical adducts to radical cations, while the electron-withdrawing NH(3)(+) group not only increases the reduction potential but also leads to fragmentation of the hydroxyl radical adduct to selenyl radicals, which are converted

  2. Comparing the gas-phase fragmentation reactions of protonated and radical cations of the tripeptides GXR

    Science.gov (United States)

    Wee, Sheena; O'Hair, Richard A. J.; McFadyen, W. David

    2004-05-01

    Electrospray ionization (ESI) mass spectrometry of methanolic solutions of mixtures of the copper salt (2,2':6',2''-terpyridine)copper(II) nitrate monohydrate ([Cu(II)(tpy)(NO3)2].H2O) and a tripeptide GXR (where X = 1 of the 20 naturally occurring amino acids) yielded [Cu(II)(tpy)(GXR)][radical sign]2+ ions, which were then subjected to collision induced dissociation (CID). In all but one case (GRR), these [Cu(II)(tpy)(GXR)][radical sign]2+ ions fragment to form odd electron GXR[radical sign]+ radical cations with sufficient abundance to examine their gas-phase fragmentation reactions. The GXR[radical sign]+ radical cations undergo a diverse range of fragmentation reactions which depend on the nature of the side chain of X. Many of these reactions can be rationalized as arising from the intermediacy of isomeric distonic ions in which the charge (i.e. proton) is sequestered by the highly basic arginine side chain and the radical site is located at various positions on the tripeptide including the peptide back bone and side chains. The radical sites in these distonic ions often direct the fragmentation reactions via the expulsion of small radicals (to yield even electron ions) or small neutrals (to form radical cations). Both classes of reaction can yield useful structural information, allowing for example, distinction between leucine and isoleucine residues. The gas-phase fragmentation reactions of the GXR[radical sign]+ radical cations are also compared to their even electron [GXR+H]+ and [GXR+2H]2+ counterparts. The [GXR+H]+ ions give fewer sequence ions and more small molecule losses while the [GXR+2H]2+ ions yield more sequence information, consistent with the [`]mobile proton model' described in previous studies. In general, all three classes of ions give complementary structural information, but the GXR[radical sign]+ radical cations exhibit a more diverse loss of small species (radicals and neutrals). Finally, links between these gas-phase results and key

  3. Tryptophan tryptophylquinone biosynthesis: a radical approach to posttranslational modification.

    Science.gov (United States)

    Davidson, Victor L; Liu, Aimin

    2012-11-01

    Protein-derived cofactors are formed by irreversible covalent posttranslational modification of amino acid residues. An example is tryptophan tryptophylquinone (TTQ) found in the enzyme methylamine dehydrogenase (MADH). TTQ biosynthesis requires the cross-linking of the indole rings of two Trp residues and the insertion of two oxygen atoms onto adjacent carbons of one of the indole rings. The diheme enzyme MauG catalyzes the completion of TTQ within a precursor protein of MADH. The preMADH substrate contains a single hydroxyl group on one of the tryptophans and no crosslink. MauG catalyzes a six-electron oxidation that completes TTQ assembly and generates fully active MADH. These oxidation reactions proceed via a high valent bis-Fe(IV) state in which one heme is present as Fe(IV)=O and the other is Fe(IV) with both axial heme ligands provided by amino acid side chains. The crystal structure of MauG in complex with preMADH revealed that catalysis does not involve direct contact between the hemes of MauG and the protein substrate. Rather it is accomplished through long-range electron transfer, which presumably generates radical intermediates. Kinetic, spectrophotometric, and site-directed mutagenesis studies are beginning to elucidate how the MauG protein controls the reactivity of the hemes and mediates the long range electron/radical transfer required for catalysis. This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology.

  4. Free Radicals and Their Role in Different Clinical Conditions: An Overview

    Directory of Open Access Journals (Sweden)

    Abheri Das Sarma

    2010-04-01

    Full Text Available Free Radicals are molecules with an unpaired electron and are important intermediates in natural processes involving cytotoxicity, control of vascular tone, and neurotransmission. Free radicals are very unstable and react quickly with other compounds, and try to capture the needed electron to gain stability. A chain reaction thus gets started. Once the process is started, it can cascade, and inally results in the disruption of a living cell. Generally, harmful effects of reactive oxygen species on the cell are most often like damage of DNA, oxidations of polydesaturated fatty acids in lipids, oxidations of amino acids in proteins, oxidatively inactivate specific enzymes by oxidation of co-factors. Free radicals cause many human diseases like cancer Alzheimer’s disease, cardiac reperfusion abnormalities, kidney disease, fibrosis, etc. The free radicals formed in our body are combated by antioxidants that safely interact with free radicals and terminate the chain reaction before vital molecules are damaged. Excessive exercise has been found to increase the free radical level in the body and causes intense damage to the Regular physical exercise enhances the antioxidant defense system and protects against exercise induced free radical damage. Apart from the destructive effects of free radical they are also responsible for some vital actions like destroy the bacteria and other cells of foreign matter, kill cancer cells, turning on and off of genes and fight infection, to keep our brain alert and in focus.

  5. Radical Innovation and Network Evolution

    NARCIS (Netherlands)

    S.M.W. Phlippen (Sandra); M. Riccaboni

    2007-01-01

    textabstractThis paper examines how a radical technological innovation affects alliance formation of firms and subsequent network structures. We use longitudinal data of interfirm R&D collaborations in the biopharmaceutical industry in which a new technological regime is established. Our findings su

  6. Wild radical square zero algebras

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    It is shown that a radical square zero algebra is wild, if and only if it is of Corner's type, and it is strictly wild if and only if it is Endo-wild. This gives a negative answer to a problem posed by Simson.

  7. Is Radical Innovation Management Misunderstood?

    DEFF Research Database (Denmark)

    Kristiansen, Jimmi Normann; Gertsen, Frank

    2015-01-01

    This paper poses a critical view on radical innovation (RI) management research and practice. The study investigates how expected RI performance influences firms’ under- standing of their RI capability. RI performance is often based on output measures such as market shares or fiscal return...

  8. Exploring the Theories of Radicalization

    Directory of Open Access Journals (Sweden)

    Maskaliūnaitė Asta

    2015-12-01

    Full Text Available After the London bombings in July 2005, the concern of terrorism scholars and policy makers has turned to “home-grown” terrorism and potential for political violence from within the states. “Radicalization” became a new buzz word. This article follows a number of reviews of the literature on radicalization and offers another angle for looking at this research. First, it discusses the term “radicalization” and suggests the use of the following definition of radicalization as a process by which a person adopts belief systems which justify the use of violence to effect social change and comes to actively support as well as employ violent means for political purposes. Next, it proposes to see the theories of radicalization focusing on the individual and the two dimensions of his/her motivation: whether that motivation is internal or external and whether it is due to personal choice or either internal (due to some psychological traits or external compulsion. Though not all theories fall neatly within these categories, they make it possible to make comparisons of contributions from a variety of different areas thus reflecting on the interdisciplinary nature of the study of terrorism in general and radicalization as a part of it.

  9. Radical review of NHS funding.

    Science.gov (United States)

    1988-02-06

    The Government is to carry out a radical review of the way the NHS is funded, Prime Minister Margaret Thatcher confirmed last week. And she hinted that she herself would be taking a leading role in drawing up proposals for reform.

  10. Detecting Social Polarization and Radicalization

    DEFF Research Database (Denmark)

    Qureshi, Pir Abdul Rasool; Memon, Nasrullah; Wiil, Uffe Kock

    2011-01-01

    This paper proposes a novel system to detect social polarization and to estimate the chances of violent radicalization associated with it. The required processes for such a system are indicated; it is also analyzed how existing technologies can be integrated into the proposed system to fulfill...

  11. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-01-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of "narrow mental states"; that is, the idea that the mental content of an individual can be fully characterised without…

  12. Lycopene inhibits the isomerization of β-carotene during quenching of singlet oxygen and free radicals.

    Science.gov (United States)

    Heymann, Thomas; Heinz, Philipp; Glomb, Marcus A

    2015-04-01

    The present study aimed to investigate the influence of singlet oxygen and radical species on the isomerization of carotenoids. On the one hand, lycopene and β-carotene standards were incubated with 1,4-dimethylnaphthalene-1,4-endoperoxide that produced singlet oxygen in situ. (13Z)- and (15Z)-β-carotene were preferentially generated at low concentrations of singlet oxygen, while high concentrations resulted in formation of (9Z)-β-carotene. The addition of different concentrations of lycopene led to the same isomerization progress of β-carotene, but resulted in a decreased formation of (9Z)-β-carotene and retarded degradation of (all-E)-β-carotene. On the other hand, isomerization of β-carotene and lycopene was induced by ABTS-radicals, too. As expected from the literature, chemical quenching was observed especially for lycopene, while physical quenching was preferred for β-carotene. Mixtures of β-carotene and lycopene resulted in a different isomerization progress compared to the separate β-carotene model. As long as lycopene was present, almost no isomerization of β-carotene was triggered; after that, strong formation of (13Z)-, (9Z)-, and (15Z)-β-carotene was initiated. In summary, lycopene protected β-carotene against isomerization during reactions with singlet oxygen and radicals. These findings can explain the pattern of carotenoid isomers analyzed in fruits and vegetables, where lycopene containing samples showed higher (all-E)/(9Z)-β-carotene ratios, and also in in vivo samples such as human blood plasma.

  13. Generation of naphthoquinone radical anions by electrospray ionization: solution, gas-phase, and computational chemistry studies.

    Science.gov (United States)

    Vessecchi, Ricardo; Naal, Zeki; Lopes, José N C; Galembeck, Sérgio E; Lopes, Norberto P

    2011-06-02

    Radical anions are present in several chemical processes, and understanding the reactivity of these species may be described by their thermodynamic properties. Over the last years, the formation of radical ions in the gas phase has been an important issue concerning electrospray ionization mass spectrometry studies. In this work, we report on the generation of radical anions of quinonoid compounds (Q) by electrospray ionization mass spectrometry. The balance between radical anion formation and the deprotonated molecule is also analyzed by influence of the experimental parameters (gas-phase acidity, electron affinity, and reduction potential) and solvent system employed. The gas-phase parameters for formation of radical species and deprotonated species were achieved on the basis of computational thermochemistry. The solution effects on the formation of radical anion (Q(•-)) and dianion (Q(2-)) were evaluated on the basis of cyclic voltammetry analysis and the reduction potentials compared with calculated electron affinities. The occurrence of unexpected ions [Q+15](-) was described as being a reaction between the solvent system and the radical anion, Q(•-). The gas-phase chemistry of the electrosprayed radical anions was obtained by collisional-induced dissociation and compared to the relative energy calculations. These results are important for understanding the formation and reactivity of radical anions and to establish their correlation with the reducing properties by electrospray ionization analyses.

  14. Reactions of Hydroxyalkyl Radicals with Cysteinyl Peptides in a NanoESI Plume

    Science.gov (United States)

    Stinson, Craig A.; Xia, Yu

    2014-07-01

    In biological systems, carbon-centered small molecule radicals are primarily formed via external radiation or internal radical reactions. These radical species can react with a variety of biomolecules, most notably nucleic acids, the consequence of which has possible links to gene mutation and cancer. Sulfur-containing peptides and proteins are reactive toward a variety of radical species and many of them behave as radical scavengers. In this study, the reactions between alkyl alcohol carbon-centered radicals (e.g., •CH2OH for methanol) and cysteinyl peptides within a nanoelectrospray ionization (nanoESI) plume were explored. The reaction system involved ultraviolet (UV) irradiation of a nanoESI plume using a low pressure mercury lamp consisting of 185 and 254 nm emission bands. The alkyl alcohol was added as solvent into the nanoESI solution and served as the precursor of hydroxyalkyl radicals upon UV irradiation. The hydroxyalkyl radicals subsequently reacted with cysteinyl peptides either containing a disulfide linkage or free thiol, which led to the formation of peptide- S-hydroxyalkyl product. This radical reaction coupled with subsequent MS/MS was shown to have analytical potential by cleaving intrachain disulfide linked peptides prior to CID to enhance sequence information. Tandem mass spectrometry via collision-induced dissociation (CID), stable isotope labeling, and accurate mass measurement were employed to verify the identities of the reaction products.

  15. Photochemical synthesis of simple organic free radicals on simulated planetary surfaces - An ESR study

    Science.gov (United States)

    Tseng, S.-S.; Chang, S.

    1975-01-01

    Electron spin resonance (ESR) spectroscopy provided evidence for formation of hydroxyl radicals during ultraviolet photolysis (254 nm) at -170 C of H2O adsorbed on silica gel or of silica gel alone. The carboxyl radical was observed when CO or CO2 or a mixture of CO and CO2 adsorbed on silica gel at -170 C was irradiated. The ESR signals of these radicals slowly disappeared when the irradiated samples were warmed to room temperature. However, reirradiation of CO or CO2, or the mixture CO and CO2 on silica gel at room temperature then produced a new species, the carbon dioxide anion radical, which slowly decayed and was identical with that produced by direct photolysis of formic acid adsorbed on silica gel. The primary photochemical process may involve formation of hydrogen and hydroxyl radicals. Subsequent reactions of these radicals with adsorbed CO or CO2 or both yield carboxyl radicals, CO2H, the precursors of formic acid. These results confirm the formation of formic acid under simulated Martian conditions and provide a mechanistic basis for gauging the potential importance of gas-solid photochemistry for chemical evolution on other extraterrestrial bodies, on the primitive earth, and on dust grains in the interstellar medium.

  16. Preclinical screening of histone deacetylase inhibitors combined with ABT-737, rhTRAIL/MD5-1 or 5-azacytidine using syngeneic Vk*MYC multiple myeloma.

    Science.gov (United States)

    Matthews, G M; Lefebure, M; Doyle, M A; Shortt, J; Ellul, J; Chesi, M; Banks, K M; Vidacs, E; Faulkner, D; Atadja, P; Bergsagel, P L; Johnstone, R W

    2013-09-12

    Multiple myeloma (MM) is an incurable malignancy with an unmet need for innovative treatment options. Histone deacetylase inhibitors (HDACi) are a new class of anticancer agent that have demonstrated activity in hematological malignancies. Here, we investigated the efficacy and safety of HDACi (vorinostat, panobinostat, romidepsin) and novel combination therapies using in vitro human MM cell lines and in vivo preclinical screening utilizing syngeneic transplanted Vk*MYC MM. HDACi were combined with ABT-737, which targets the intrinsic apoptosis pathway, recombinant human tumour necrosis factor-related apoptosis-inducing ligand (rhTRAIL/MD5-1), that activates the extrinsic apoptosis pathway or the DNA methyl transferase inhibitor 5-azacytidine. We demonstrate that in vitro cell line-based studies provide some insight into drug activity and combination therapies that synergistically kill MM cells; however, they do not always predict in vivo preclinical efficacy or toxicity. Importantly, utilizing transplanted Vk*MYC MM, we report that panobinostat and 5-azacytidine synergize to prolong the survival of tumor-bearing mice. In contrast, combined HDACi/rhTRAIL-based strategies, while efficacious, demonstrated on-target dose-limiting toxicities that precluded prolonged treatment. Taken together, our studies provide evidence that the transplanted Vk*MYC model of MM is a useful screening tool for anti-MM drugs and should aid in the prioritization of novel drug testing in the clinic.

  17. Effect of Hetero Atom on the Hammett’s Reaction Constant (ρ from the Physical Basis of Dissociation Equilibriums of (Dithio Benzoic Acids and (Thio Phenols and Its Application to Solvolysis Reactions and Some Free Radical Reactions

    Directory of Open Access Journals (Sweden)

    Jagannadham Vandanapu

    2012-01-01

    Full Text Available The emergence of putative Hammett equation in mid 1930s was a boon to physical-organic chemists to elucidate the reaction mechanisms of several organic reactions. Based on the concept of this equation several hundreds of papers have emerged in chemical literature in the last century on the effect of structure, on reactivity, and very few on thermodynamic stability and kinetic reactivity of intermediates. In this article an attempt is made to explain the effect of hetero atom on Hammett’s reaction constant (ρ taking the dissociation equilibriums of benzoic acids, dithiobenzoic acids, phenols, and thiophenols.

  18. Oxygen free radicals in rheumatoid arthritis

    NARCIS (Netherlands)

    P. Biemond (Pieter)

    1986-01-01

    textabstractCurrent knowledge strongly suggests that oxygen free radicals are involved in the pathogenesis of RA. Additional information about the mechanism of free radical attack is necessary in order to find out if interaction with the mechanism of free radical damage can be used in the treatment

  19. DNA binding hydroxyl radical probes

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Vicky J.; Konigsfeld, Katie M.; Aguilera, Joe A. [Department of Radiology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States); Milligan, Jamie R., E-mail: jmilligan@ucsd.edu [Department of Radiology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States)

    2012-01-15

    The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different chromophores, which produce fluorescent products when hydroxylated. Of these, the coumarin system suffers from the fewest disadvantages. We have therefore examined its behavior when linked to a cationic peptide ligand designed to bind strongly to DNA. - Highlights: > Examined four aromatic groups as a means to detect hydroxyl radicals by fluorescence. > Coumarin system suffers from the fewest disadvantages. > Characterized its reactivity when linked to a hexa-arginine peptide.

  20. Highly durable photochromic radical complexes having no steric protections of radicals.

    Science.gov (United States)

    Kobayashi, Yoichi; Mishima, Yasuhiro; Mutoh, Katsuya; Abe, Jiro

    2017-04-21

    Steric protection groups are usually necessary for stable radicals. However, here, we developed novel photochromic radical complexes which generate sterically unprotected imidazolyl and phenoxyl radicals upon UV light irradiation based on the phenoxyl-imidazolyl radical complex (PIC) framework. These photochromic compounds show excellent durability against repeated irradiation of intense nanosecond laser pulses even in polar protic solvents, such as ethanol.

  1. Geoscientists and the Radical Middle

    Science.gov (United States)

    Tinker, S. W.

    2015-12-01

    Addressing the great challenges facing society requires industry, government, and academia to work together. I call this overlap space, where compromises are made and real solutions determined, the Radical Middle. Radical because it can appear at times as if the loudest and most publicly influential voices lie outside of the actual solution space, content to provoke but not problem-solve. One key area where geoscientists can play a lead role in the Radical Middle is in the overlap between energy, the environment, and the economy. Globally, fossil fuels still represent 85% of the aggregate energy mix. As existing conventional oil and natural-gas reservoir production continues to slowly decline, unconventional reservoirs, led today by shale and other more expensive resources, will represent a growing part of the oil and gas production mix. Many of these unconventional reservoirs require hydraulic fracturing. The positive economic impact of hydraulic fracturing and associated natural gas and oil production on the United States economy is well documented and undeniable. Yet there are environmental concerns about fracking, and some states and nations have imposed moratoria. This energy-environment-economy space is ideal for leadership from the geosciences. Another such overlap space is the potential for geoscience leadership in relations with China, whose economy and global presence continue to expand. Although China is building major hydropower and natural-gas power plants, as well as nuclear reactors, coal is still king—with the associated environmental impacts. Carbon sequestration—onshore in brine and to enhance oil recovery, as well as offshore—could prove viable. It is vital that educated and objective geoscientists from industry, government, and academia leave their corners and work together in the Radical Middle to educate the public and develop and deliver balanced, economically sensible energy and environmental strategies.

  2. Donepezil, an acetylcholine esterase inhibitor, and ABT-239, a histamine H3 receptor antagonist/inverse agonist, require the integrity of brain histamine system to exert biochemical and procognitive effects in the mouse.

    Science.gov (United States)

    Provensi, Gustavo; Costa, Alessia; Passani, M Beatrice; Blandina, Patrizio

    2016-10-01

    Histaminergic H3 receptors (H3R) antagonists enhance cognition in preclinical models and modulate neurotransmission, in particular acetylcholine (ACh) release in the cortex and hippocampus, two brain areas involved in memory processing. The cognitive deficits seen in aging and Alzheimer's disease have been associated with brain cholinergic deficits. Donepezil is one of the acetylcholinesterase (AChE) inhibitor approved for use across the full spectrum of these cognitive disorders. We addressed the question if H3R antagonists and donepezil require an intact histamine neuronal system to exert their procognitive effects. The effect of the H3R antagonist ABT-239 and donepezil were evaluated in the object recognition test (ORT), and on the level of glycogen synthase kinase 3 beta (GSK-3β) phosphorylation in normal and histamine-depleted mice. Systemic administration of ABT-239 or donepezil ameliorated the cognitive performance in the ORT. However, these compounds were ineffective in either genetically (histidine decarboxylase knock-out, HDC-KO) or pharmacologically, by means of intracerebroventricular (i.c.v.) injections of the HDC irreversible inhibitor a-fluoromethylhistidine (a-FMHis), histamine-deficient mice. Western blot analysis revealed that ABT-239 or donepezil systemic treatments increased GSK-3β phosphorylation in cortical and hippocampal homogenates of normal, but not of histamine-depleted mice. Furthermore, administration of the PI3K inhibitor LY294002 that blocks GSK-3β phosphorylation, prevented the procognitive effects of both drugs in normal mice. Our results indicate that both donepezil and ABT-239 require the integrity of the brain histaminergic system to exert their procognitive effects and strongly suggest that impairments of PI3K/AKT/GSK-3β intracellular pathway activation is responsible for the inefficacy of both drugs in histamine-deficient animals.

  3. The first characterization of free radicals formed from cellular COX-catalyzed peroxidation.

    Science.gov (United States)

    Gu, Yan; Xu, Yi; Law, Benedict; Qian, Steven Y

    2013-04-01

    Through free radical-mediated peroxidation, cyclooxygenase (COX) can metabolize dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA) to form well-known bioactive metabolites, namely, the 1-series of prostaglandins (PGs1) and the 2-series of prostaglandins (PGs2), respectively. Unlike PGs2, which are generally viewed as proinflammatory and procarcinogenic PGs, PGs1 may possess anti-inflammatory and anti-cancer activity. Previous studies using ovine COX along with spin trapping and the LC/ESR/MS technique have shown that certain exclusive free radicals are generated from different free radical reactions in DGLA and AA peroxidation. However, it has been unclear whether the differences were associated with the contrasting bioactivity of DGLA vs AA. The aim of this study was to refine the LC/MS and spin trapping technique to make it possible for the association between free radicals and cancer cell growth to be directly tested. Using a colon cancer cell line, HCA-7 colony 29, and LC/MS along with a solid-phase extraction, we were able to characterize the reduced forms of radical adducts (hydroxylamines) as the free radicals generated from cellular COX-catalyzed peroxidation. For the first time, free radicals formed in the COX-catalyzed peroxidation of AA vs DGLA and their association with cancer cell growth were assessed (cell proliferation via MTS and cell cycle distribution via propidium iodide staining) in the same experimental setting. The exclusive free radicals formed from the COX-catalyzed peroxidation of AA and DGLA were shown to be correlated with the cell growth response. Our results indicate that free radicals generated from the distinct radical reactions in COX-catalyzed peroxidation may represent the novel metabolites of AA and DGLA that correspond to their contrasting bioactivity.

  4. Radical Reactions in the Gas Phase: Recent Development and Application in Biomolecules

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2014-01-01

    Full Text Available This review summarizes recent literature describing the use of gas phase radical reactions for structural characterization of complex biomolecules other than peptides. Specifically, chemical derivatization, in-source chemical reaction, and gas phase ion/ion reactions have been demonstrated as effective ways to generate radical precursor ions that yield structural informative fragments complementary to those from conventional collision-induced dissociation (CID. Radical driven dissociation has been applied to a variety of biomolecules including peptides, nucleic acids, carbohydrates, and phospholipids. The majority of the molecules discussed in this review see limited fragmentation from conventional CID, and the gas phase radical reactions open up completely new dissociation channels for these molecules and therefore yield high fidelity confirmation of the structures of the target molecules. Due to the extensively studied peptide fragmentation, this review focuses only on nonpeptide biomolecules such as nucleic acids, carbohydrates, and phospholipids.

  5. Electron spin resonance studies on reduction process of nitroxyl spin radicals used in molecular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Dhas, M. Kumara; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com [Department of Physics, NMSSVN College, Nagamalai, Madurai-625019, Tamilnadu (India); Jawahar, A. [Department of Chemistry, NMSSVN College, Nagamalai, Madurai-625019, Tamilnadu (India)

    2014-04-24

    The Electron spin resonance studies on the reduction process of nitroxyl spin probes were carried out for 1mM {sup 14}N labeled nitroxyl radicals in pure water and 1 mM concentration of ascorbic acid as a function of time. The electron spin resonance parameters such as signal intensity ratio, line width, g-value, hyperfine coupling constant and rotational correlation time were determined. The half life time was estimated for 1mM {sup 14}N labeled nitroxyl radicals in 1 mM concentration of ascorbic acid. The ESR study reveals that the TEMPONE has narrowest line width and fast tumbling motion compared with TEMPO and TEMPOL. From the results, TEMPONE has long half life time and high stability compared with TEMPO and TEMPOL radical. Therefore, this study reveals that the TEMPONE radical can act as a good redox sensitive spin probe for molecular imaging.

  6. pRb/E2F-1-mediated caspase-dependent induction of Noxa amplifies the apoptotic effects of the Bcl-2/Bcl-xL inhibitor ABT-737.

    Science.gov (United States)

    Bertin-Ciftci, J; Barré, B; Le Pen, J; Maillet, L; Couriaud, C; Juin, P; Braun, F

    2013-05-01

    Although Bcl-2 family members control caspase activity by regulating mitochondrial permeability, caspases can, in turn, amplify the apoptotic process upstream of mitochondria by ill-characterized mechanisms. We herein show that treatment with a potent inhibitor of Bcl-2 and Bcl-xL, ABT-737, triggers caspase-dependent induction of the BH3-only protein, Mcl-1 inhibitor, Noxa. RNA interference experiments reveal that induction of Noxa, and subsequent cell death, rely not only on the transcription factor E2F-1 but also on its regulator pRb. In response to ABT-737, pRb is cleaved by caspases into a p68Rb form that still interacts with E2F-1. Moreover, pRb occupies the noxa promoter together with E2F-1, in a caspase-dependent manner upon ABT-737 treatment. Thus, caspases contribute to trigger the mitochondrial apoptotic pathway by coupling Bcl-2/Bcl-xL inhibition to that of Mcl-1, via the pRb/E2F-1-dependent induction of Noxa.

  7. LETTING GO: DE-RADICALIZATION IN EGYPT

    Directory of Open Access Journals (Sweden)

    Zeynep Kaya

    2016-03-01

    Full Text Available The literature on the causes of how terrorist organizations are formed and how counter terrorism measures can be more effective is immense. What is novel in terrorism literature is de-radicalization in terrorist organizations. This paper hopes to shed light on the de-radicalization process in terrorist organizations based in Egypt. In order to achieve that goal, the first part of the paper will deal with the de-radicalization process. The second part will briefly describe the major radical terrorist organizations that are effective in Egypt. The last part will combine the two parts and bring in suggestions on the de-radicalization process itself. Terrorism and de-radicalization are complicated threats to nearly all societies. Therefore, it is important to go beyond security and intelligence approaches and take proactive measures. It is best to view what is de-radicalization and how it can be achieved.

  8. Oxidative stress, free radicals and protein peroxides.

    Science.gov (United States)

    Gebicki, Janusz M

    2016-04-01

    Primary free radicals generated under oxidative stress in cells and tissues produce a cascade of reactive secondary radicals, which attack biomolecules with efficiency determined by the reaction rate constants and target concentration. Proteins are prominent targets because they constitute the bulk of the organic content of cells and tissues and react readily with many of the secondary radicals. The reactions commonly lead to the formation of carbon-centered radicals, which generally convert in vivo to peroxyl radicals and finally to semistable hydroperoxides. All of these intermediates can initiate biological damage. This article outlines the advantages of the application of ionizing radiations to studies of radicals, with particular reference to the generation of desired radicals, studies of the kinetics of their reactions and correlating the results with events in biological systems. In one such application, formation of protein hydroperoxides in irradiated cells was inhibited by the intracellular ascorbate and glutathione.

  9. Study on capacities of free radical effects by Walnut peel in vitro%核桃青皮在体外清除自由基的活性研究

    Institute of Scientific and Technical Information of China (English)

    吕海宁; 折改梅; 郭志琴; 折冬梅

    2011-01-01

    目的 研究核桃青皮体外清除自由基的活性.方法 采用清除2,2-二苯基苦味酰基苯肼基(DPPH)和2,2'-连氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)自由基的方法,对核桃青皮乙醇提取物不同极性部位进行清除自由基能力的综合评价.结果 石油醚、氯仿、乙酸乙酯、正丁醇、水萃取核桃青皮清除DPPH自由基的IC39分别为27.0、19.0、5.6、8.8、44.0 mg·L-1,清除ABTS自由基的IC50分别为114.0、82.6、13.6、32.0、302.0 mg·L-1.清除自由基的能力依次为:乙酸乙酯部位>正丁醇部位>氯仿部位>石油醚部位>水部位,其中,乙酸乙酯部位清除DPPH和ABTS自由基的能力高于同浓度的Vit C和Vit E.结论 核桃青皮提取液的乙酸乙酯、正丁醇萃取部位具有很好的清除自由基活性,前者活性强于后者,是天然抗氧化物质的良好来源.%OBJECTIVE To study the capacitis of free radical effects by extracts from walnut peel (Juglans regia).METHODS The capacitis of free radical effects by different extracts from walnut peel were measured by DPPH assay and ABTS assay.RESULTS All extracts (petroleum ether, chloroform, ethyl acetate, n - butanol, aqueous solution) from walnut peel showed strong capacitis of free radical effects The IC50 of DPPH free radical effects were 27.0,19.0,5.6,8.8,44.0 rag · L- 1, respectively.The IC50 of scavenging ABTS free radicals were 114.0,82.6,13.6,32.0 and 302.0 mg· L- 1 ,respectively.The capabilitis of free radical effects in five solvents were ethyl acetate > n - butanol > chloroform > petroleum ether > aqueous solution.The capabilitis of DPPH and ABTS free radical effects by ethyl acetate extracts was stronger than Vit C and Vit E.CONCLUSION The ethyl acetate extracts and the n - butanol extracts exhibited strong capacitis of free radical effects.Walnut peel proves to be a good resource of natural antioxidant product.

  10. Imaging free radicals in organelles, cells, tissue, and in vivo with immuno-spin trapping.

    Science.gov (United States)

    Mason, Ronald Paul

    2016-08-01

    The accurate and sensitive detection of biological free radicals in a reliable manner is required to define the mechanistic roles of such species in biochemistry, medicine and toxicology. Most of the techniques currently available are either not appropriate to detect free radicals in cells and tissues due to sensitivity limitations (electron spin resonance, ESR) or subject to artifacts that make the validity of the results questionable (fluorescent probe-based analysis). The development of the immuno-spin trapping technique overcomes all these difficulties. This technique is based on the reaction of amino acid- and DNA base-derived radicals with the spin trap 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) to form protein- and DNA-DMPO nitroxide radical adducts, respectively. These adducts have limited stability and decay to produce the very stable macromolecule-DMPO-nitrone product. This stable product can be detected by mass spectrometry, NMR or immunochemistry by the use of anti-DMPO nitrone antibodies. The formation of macromolecule-DMPO-nitrone adducts is based on the selective reaction of free radical addition to the spin trap and is thus not subject to artifacts frequently encountered with other methods for free radical detection. The selectivity of spin trapping for free radicals in biological systems has been proven by ESR. Immuno-spin trapping is proving to be a potent, sensitive (a million times higher sensitivity than ESR), and easy (not quantum mechanical) method to detect low levels of macromolecule-derived radicals produced in vitro and in vivo. Anti-DMPO antibodies have been used to determine the distribution of free radicals in cells and tissues and even in living animals. In summary, the invention of the immuno-spin trapping technique has had a major impact on the ability to accurately and sensitively detect biological free radicals and, subsequently, on our understanding of the role of free radicals in biochemistry, medicine and toxicology.

  11. Screening of various botanical extracts for antioxidant activity using DPPH free radical method.

    Science.gov (United States)

    Waqas, Muhammad Khurram; Saqib, Najam-Us; Rashid, Saeed-Ur; Shah, Pervaiz Akhtar; Akhtar, Naveed; Murtaza, Ghulam

    2013-01-01

    Aiming at the exploration of herbal use by society, crude extracts of the seeds of some commonly used medicinal plants (Vitis vinifera, Tamarindus indica and Glycin max) were screened for their free radical scavenging properties using ascorbic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The overall antioxidant activity of grape seeds (Vitis vinifera) was the strongest, followed in descending order by soybean (Glycin max) and tamarind (Tamarindus indica). The seeds extract of Vitis vinifera, Glycin max and Tamarindus indica showed 85.61%, 83.45% and 79.26%, DPPH scavenging activity respectively.

  12. Hydroxyl Radical and Its Scavengers in Health and Disease

    Directory of Open Access Journals (Sweden)

    Boguslaw Lipinski

    2011-01-01

    Full Text Available It is generally believed that diseases caused by oxidative stress should be treated with antioxidants. However, clinical trials with such antioxidants as ascorbic acid and vitamin E, failed to produce the expected beneficial results. On the other hand, important biomolecules can be modified by the introduction of oxygen atoms by means of non-oxidative hydroxyl radicals. In addition, hydroxyl radicals can reduce disulfide bonds in proteins, specifically fibrinogen, resulting in their unfolding and scrambled refolding into abnormal spatial configurations. Consequences of this reaction are observed in many diseases such as atherosclerosis, cancer and neurological disorders, and can be prevented by the action of non-reducing substances. Moreover, many therapeutic substances, traditionally classified as antioxidants, accept electrons and thus are effective oxidants. It is described in this paper that hydroxyl radicals can be generated by ferric ions without any oxidizing agent. In view of the well-known damaging effect of poorly chelated iron in the human body, numerous natural products containing iron binding agents can be essential in the maintenance of human health. However, beneficial effects of the great number of phytochemicals that are endowed with hydroxyl radical scavenging and/or iron chelating activities should not be considered as a proof for oxidative stress.

  13. Effect of electron-withdrawing power of the substituted group on ${}^{\\bullet}$OH radical reaction with substituted aryl sulphides: A pulse radiolysis study

    Indian Academy of Sciences (India)

    Hari Mohan

    2002-12-01

    In neutral aqueous solution of (phenylthio)acetic acid, hydroxyl radical is observed to react with a bimolecular rate constant of 7.2 × 109 dm3 mol-1 s-1 and the transient absorption bands are assigned to ${}^{\\bullet}$OH radical addition to benzene and sulphur with a rough estimated values of 50 and 40% respectively. The reaction of the ${}^{\\bullet}$OH radical with diphenyl sulphide ( = 4.3 × 108 dm3 mol-1 s-1) is observed to take place with formation of solute radical cation, OH-adduct at sulphur and benzene with estimated values of about 12, 28 and 60% respectively. The transient absorption bands observed on reaction of ${}^{\\bullet}$OH radical, in neutral aqueous solution of 4-(methylthio) phenyl acetic acid, are assigned to solute radical cation (max = 550 and 730 nm), OH-adduct at sulphur (max = 360 nm) and addition at benzene ring (max = 320 nm). The fraction of ${}^{\\bullet}$OH radical reacting to form solute radical cation is observed to depend on the electron-withdrawing power of substituted group. In acidic solutions, depending on the concentration of acid and electron-withdrawing power, solute radical cation is the only transient species formed on reaction of ${}^{\\bullet}$OH radical with the sulphides studied.

  14. Biochemical characterization of radical scavenging polyphenols from Nyctanthes arbortristis

    Directory of Open Access Journals (Sweden)

    S Meghashri

    2012-01-01

    Full Text Available Context: Antioxidants are quenchers of free radical that are responsible for inducing oxidative stress generated via reactive oxygen species-induced degenerative diseases such as cancer, diabetes, and cardiovascular diseases etc. Plant and plant products are recognized as safe and potential health promoting and nutritive sources. Aims: To investigate the antioxidant potency of polyphenol extract (PE of Nyctanthes arbortristis leaves and identification of the active constituent by HPLC. Materials and Methods: PE of N. arbortristis leaves was investigated for antioxidant activity employing various established in vitro systems, such as lipid peroxidation in liposome, DPPH and hydroxyl radical scavenging, reducing power assay, and iron ion chelation. Identification of active constituent in PE of N. arbortristis responsible for antioxidant activity by HPLC. Statistical analysis used: All experiments were carried out in triplicates. Data were shown as mean ± standard deviation (SD. SPSS 10.0.5 version for windows (SPSS software Inc., USA computer program was used for statistical analysis. Results: Identification of active constituent in PE revealed gallic acid 75.8 ± 0.21, protocatechuic acid 14.6 ± 0.5, chlorogenic acid 6.79 ± 0.43, and caffeic acid 5.34 ± 0.2 μg/ml. PE showed strong inhibitory activity of 73% at 200 μg/ml toward lipid peroxidation in egg lecithin, concentration-dependent inhibition of deoxyribose oxidation at 200 μg/ml was 85% inhibition, and considerable antioxidant activity in DPPH radical assay system at 200 μg/ml was 79% inhibition. BHA and gallic acid showed significant observations. Conclusion: The antioxidant potency significantly correlated with the phenolic content of PE. Considering that medicinal herbs contain potent phytochemicals, which is effectively utilized for various degenerative disease, these in vitro results showed that N. arbortristis leaves could be effectively employed in functional food, to

  15. Loading of free radicals on the functional graphene combined with liquid chromatography-tandem mass spectrometry screening method for the detection of radical-scavenging natural antioxidants.

    Science.gov (United States)

    Wang, Guoying; Shi, Gaofeng; Chen, Xuefu; Chen, Fuwen; Yao, Ruixing; Wang, Zhenju

    2013-11-13

    A novel free radical reaction combined with liquid chromatography electrospray ionization tandem mass spectrometry (FRR-LC-PDA-ESI/APCI-MS/MS) screening method was developed for the detection and identification of radical-scavenging natural antioxidants. Functionalized graphene was prepared by chemical method for loading free radicals (superoxide radical, peroxyl radical and PAHs free radical). Separation was performed with and without a preliminary exposure of the sample to specific free radicals on the functionalized graphene, which can facilitate reaction kinetics (charge transfers) between free radicals and potential antioxidants. The difference in chromatographic peak areas is used to identify potential antioxidants. The structure of the antioxidants in one sample (Swertia chirayita) is identified using MS/MS and comparison with standards. Thirteen compounds were found to possess potential antioxidant activity, and their free radical-scavenging capacities were investigated. The thirteen compounds were identified as 1,3,5-trihydroxyxanthone-8-O-β-D-glucopyranoside (PD1), norswertianin (PD2), 1,3,5,8-tetrahydroxyxanthone (PD3), 3, 3', 4', 5, 8-penta hydroxyflavone-6-β-D-glucopyranosiduronic acid-6'-pentopyranose-7-O-glucopyranoside (PD4), 1,5,8-trihydroxy-3-methoxyxanthone (PD5), swertiamarin (PS1), 2-C-β-D-glucopyranosyl-1,3,7-trihydroxylxanthone (PS2), 1,3,7-trihydroxylxanthone-8-O-β-D-glucopyranoside (PL1), 1,3,8-trihydroxyl xanthone-5-O-β-D-glucopyranoside (PL2), 1,3,7-trihydroxy-8-methoxyxanthone (PL3), 1,2,3-trihydroxy-7,8-dimethoxyxanthone (PL4), 1,8-dihydroxy-2,6-dimethoxy xanthone (PL5) and 1,3,5,8-tetramethoxydecussatin (PL6). The reactivity and SC50 values of those compounds were investigated, respectively. PD4 showed the strongest capability for scavenging PAHs free radical; PL4 showed prominent scavenging capacities in the lipid peroxidation processes; it was found that all components in S. chirayita exhibited weak reactivity in the superoxide

  16. Online radicalization: the net or the netizen?

    Directory of Open Access Journals (Sweden)

    Femi Richard Omotoyinbo

    2014-10-01

    Full Text Available Purpose - Radicalization has gained some unusual prominence in the academic circles; maintaining a generic existence not only in the political sector. And with the advent of the Information Communication Technology (ICT, radicalization has begun to have some virtual dimension even in the remotest of human communities. This study seeks to mobilize a universal awareness on the collective urgency to oppose Online Radicalization (a radicalization that happens through the internet due to its propensity to engendering conflicts. It also aims at identifying the principal cause of online radicalization and steer a clear course for a practical reversal in the systems of online radicalization.Design/methodology/approach - The study is divided into three primary parts. The general notion of radicalization is the focus of the first part; which is further analysed into the levels of online radicalization with its accompanying developments and segments. The second part utilizes analytic and historical method to pinpoint the principal cause of online radicalization amidst the suspected causal factors (the Net and the Netizen. The final part analytically focuses on the Netizen (a user/citizen of the internet as the primary cause of online radicalization, and how the global community can bring about a corresponding change in the Net by the application of some measures on the Netizen.Findings - By virtue of the analytic plus historical methods employed by this study; it was initially identified that radicalization is basically having two versions which are online and offline. Further emphasis on the online version reveals that its existence is only made possible by the availability of the internet (the Net. Since the Net is a global phenomenon online radicalization is considered to be worldwide: a menace of globalization. However, the study later indicated that the Net is a facilitator and a cause of online radicalization. A view was deduced that the Netizen is

  17. Remembering Dutch-Moluccan radicalism

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2016-01-01

    This article examines memory politics in relation to radical actions of young Dutch-Moluccans, more specifically a train hijacking in 1977 at the village of De Punt in the Netherlands. The article examines how these historical events were remembered in the drama-documentary television film, De Punt......, as well as in user-generated comments in an online discussion. The television film represented an inclusive memory culture that made room for the difficult memories of all parties involved, including the radicalised, young hijackers. Based on a multidimensional model of mass media reception, the analysis...

  18. Radical conservatism and Danish imperialism

    DEFF Research Database (Denmark)

    2013-01-01

    on the basis of a close reading of their imperialist program in the pamphlet Danmark Udslettes! from 1918. Rige had been a vague term for the larger Danish polity that originated in a pre-national conceptualization of the polity as a realm. The article suggests that rige-as-realm was translated by the radical...... to signify the ambition of being a great power, the spiritual elevation of the nation through the transcendence of the decaying liberal modernity. The program addressed the tension between a conservative political attitude and modernity and thus signified a kind of reactionary modernism, which rejected...

  19. Laser spectroscopy of hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P. [Harvard Univ., Cambridge, MA (United States)

    1993-12-01

    The author reports the application of supersonic jet flash pyrolysis to the specific preparation of a range of organic radicals, biradicals, and carbenes in a skimmed molecular beam. Each species was produced cleanly and specifically, with little or no secondary reactions by the thermal dissociation of appropriately designed and synthesized organic precursors. Photoelectron spectra of the three isomeric C{sub 3}H{sub 2} carbenes, ortho-benzyne, and the {alpha},3-dehydrotoluene biradical, were used to establish adiabatic ionization potentials for use in thermochemical determinations.

  20. Aromatic-radical oxidation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Glassman, I.; Brezinsky, K. [Princeton Univ., NJ (United States)

    1993-12-01

    The research effort has focussed on discovering an explanation for the anomalously high CO{sub 2} concentrations observed early in the reaction sequence of the oxidation of cyclopentadiene. To explain this observation, a number of plausible mechanisms have been developed which now await experimental verification. One experimental technique for verifying mechanisms is to probe the reacting system by perturbing the radical concentrations. Two forms of chemical perturbation of the oxidation of cyclopentadiene were begun during this past year--the addition of NO{sub 2} and CO to the reacting mixture.

  1. Radical constructivism: Between realism and solipsism

    Science.gov (United States)

    Martínez-Delgado, Alberto

    2002-11-01

    This paper criticizes radical constructivism of the Glasersfeld type, pointing out some contradictions between the declared radical principles and their theoretical and practical development. These contradictions manifest themselves in a frequent oscillation between solipsism and realism, despite constructivist claims to be an anti-realist theory. The paper also points out the contradiction between the relativism of the radical constructivist principles and the constructivist exclusion of other epistemological or educational paradigms. It also disputes the originality and importance of the radical constructivist paradigm, suggesting the idea of an isomorphism between radical constructivist theory and contemplative realism. In addition, some pedagogical and scientific methodological aspects of the radical constructivist model are examined. Although radical constructivism claims to be a rational theory and advocates deductive thinking, it is argued that there is no logical deductive connection between the radical principles of constructivism and the radical constructivist ideas about scientific research and learning. The paper suggests the possibility of an ideological substratum in the construction and hegemonic success of subjective constructivism and, finally, briefly advances an alternative realist model to epistemological and educational radical constructivism.

  2. In vitro radical scavenging activity of two Columbian Magnoliaceae

    Science.gov (United States)

    Puertas M., Miguel A.; Mesa v., Ana M.; Sáez v., Jairo A.

    2005-08-01

    The recent interest in the conservation of the tropical forest is due, at least in part, to the potential economic and health benefits that can be exploited from several plants. This report shows the in vitro antioxidant activity of some fractions isolated from leaves of two Columbian Magnoliaceae, Talauma hernandezii G. Lozano-C and Dugandiodendron yarumalense Lozano. The activity was determined using the radical monocation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) and the stable free radical 2-2-diphenyl-1-picrylhydrazyl (DPPH·), as part of general biological screening of these plants. The antioxidant capacity obtained from fractions was similar to those of α-tocopherol, tert-butylated hydroxyanisole (BHA), and ascorbic acid. The most active scavenger extract was the fraction 7 (TAA = 48.6 mmol Trolox/kg extract and IC50 ≤ 0.01 kg extract/mmol DPPH); and the least active was the fraction 1 (TAA = 11.23 mmol Trolox/kg extract and IC50 = 0.21 kg extract/mmol DPPH) all of them isolated from D. yarumalense. These results suggest that these plants can be attractive as source of antioxidant compounds with the ability to reduce radicals like ATBS and DPPH.

  3. Inhibition of radical-induced DNA strand breaks by water-soluble constituents of coffee: phenolics and caffeine metabolites.

    Science.gov (United States)

    Rathod, M A; Patel, D; Das, A; Tipparaju, S R; Shinde, S S; Anderson, R F

    2013-07-01

    Epidemiological studies have associated coffee consumption with an inverse risk of developing Parkinson's disease, hepatocellular carcinoma and cirrhosis. The molecular mechanisms by which low concentrations of the constituents of coffee measured in human plasma can reduce the incidence of such diseases are not clear. Using an in vitro plasmid DNA system and radiolytically generated reactive oxygen species under constant radical scavenging conditions, we have shown that coffee chlorogenic acid, its derivatives and certain metabolites of caffeine reduce some of the free radical damage sustained to the DNA. A reduction in the amount of prompt DNA single-strand breaks (SSBs) was observed for all compounds whose radical one-electron reduction potential is < 1.0 V. However, except for chlorogenic acid, the compounds were found to be inactive in reducing the amount of radical damage to the DNA bases. These results support a limited antioxidant role for such compounds in their interaction with DNA radicals.

  4. An 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)-immobilized electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid.

    Science.gov (United States)

    Chih, Yi-Kai; Yang, Ming-Chang

    2013-06-01

    An 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS)-immobilized carbon nanotube (CNT) electrode was used to simultaneously detect dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) with differential pulse voltammetry. When ABTS was immobilized onto the CNT electrode in the presence of DA, UA and 100 μM AA, the sensitivity to DA increased from 0.600 (±0.013) to 1.334 (±0.010) μA/μM in the concentration ranges of 0.90-10 μM and 1.87-20 μM, respectively, and the sensitivity to UA increased from 0.030 (±0.005) to 0.078 (±0.006) μA/μM in the concentration ranges of 2.16-240 μM and 3.07-400 μM, respectively. These findings demonstrate that the ABTS-immobilized CNT electrode attained a higher sensitivity to UA and also a wider linear range of concentrations.

  5. EPR spin trapping of protein radicals

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Hawkins, Clare Louise

    2004-01-01

    Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress...... and via enzymatic reactions. Over the last 15 years this technique has also found increasing use in detecting and identifying radicals formed on biological macromolecules as a result of either radical reactions or enzymatic processes. Though the EPR signals that result from the trapping of large, slowly...... tumbling radicals are often broad and relatively poor in distinctive features, a number of techniques have been developed that allow a wealth of information to be obtained about the nature, site, and reactions of such radicals. This article summarizes recent developments in this area and reviews selected...

  6. Radical Reactions and Its Synthetic Application

    Institute of Scientific and Technical Information of China (English)

    Takeaki Naito

    2005-01-01

    @@ 1Introduction Strategies involving radical reactions have become preeminent tools in organic synthesis. Free radical-mediated cyclization has developed as a powerful method for preparing various types of cyclic compounds via carbon-carbon bond-forming processes. In order to develop effective and convenient methods for the synthesis of biologically active cyclic amines, we have focused our efforts on radical reactions using aldehydes, ketones,and C-C multiple bonds as a radical precursor and/or an oxime ether, hydrazone, and nitrone as a radical acceptor. In this lecture, I would like to talk on radical addition-cyclization of oxime ether and its application to the synthesis of martinellines.

  7. In vitro free radical scavenging activity of Ixora coccinea L

    Directory of Open Access Journals (Sweden)

    Moni Rani Saha

    2008-06-01

    Full Text Available Antioxidant activity of the methanol extract of Ixora coccinea L. was determined by DPPH free radical scavenging assay, reducing power and total antioxidant capacity using phosphomolybdenum method. Preliminary phytochemical screening revealed that the extract of the flower of I. coccinea possesses flavonoids, steroids and tannin materials. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner and remarkable activities to scavenge reactive oxygen species (ROS may be attributed to the high amount of hydrophilic phenolics. In DPPH radical scavenging assay the IC50 value of the extract was found to be 100.53 μg/mL while ascorbic acid had the IC50 value 58.92 μg/mL. Moreover, I. coccinea extract showed strong reducing power and total antioxidant capacity.

  8. Radicalization In Pakistan And The Spread Of Radical Islam In Pakistan

    Directory of Open Access Journals (Sweden)

    Bahir ahmad

    2015-08-01

    Full Text Available ABSTRACT It is pertinent to mention that radicalism is not intrinsic to Islam and radical interpretations of the religion or for that matter may occur within any way of life and religion Saikal 2003 and yet the question remains as to why Muslims in certain geographical regions have more radical approaches towards their religion and also that what are the causes of such radicalization. Becoming a radical Muslim is not even a matter of a day nor is it a sudden process. There are several reasons behind making a person radical peaceful angry smiling or tolerant. For knowing the reason behind radicalization or radicals persons one has to understand the causes. Tracing these causes is one of the ways to eliminate such behavior. The first step in the elimination of the radical sentiments in a person is to develop peace in his personality Fair Malhotra amp Shapiro 2010. The chapter which has been addressed here is going to shed light on the roots and symptoms of the radicalism. There will be a brief discussion on how the roots of radicalism can be traced and can be eliminated. The assessment and discussion will be conducted on the parameters of the economy media politics and theology from social cultural point of view. According to the analysis of Ahrari 2000 political factor is one of the major and direct factors which have resulted in causing of the radicalism. These factors however intertwine with one another. Radical actions cannot take place only because of the political factors.

  9. Serendipitous Findings While Researching Oxygen Free Radicals

    OpenAIRE

    Floyd, Robert A.

    2009-01-01

    This review is based on the honor of receiving the Discovery Award from the Society of Free Radical Biology and Medicine. The review is reflective and presents our thinking which led to experiments that yielded novel observations. Critical questioning of our understanding of oxygen free radicals in biomedical problems led us to use and develop more direct and extremely sensitive methods. This included nitrone free radical spin-trapping and HPLC-electrochemical detection. This technology led t...

  10. Bioinspired terpene synthesis: a radical approach.

    Science.gov (United States)

    Justicia, José; Álvarez de Cienfuegos, Luis; Campaña, Araceli G; Miguel, Delia; Jakoby, Verena; Gansäuer, Andreas; Cuerva, Juan M

    2011-07-01

    This tutorial review highlights the development of radical-based bioinspired synthesis of terpenes from the initial proposal to the development of modern catalytic methods for performing such processes. The power of the radical approach is demonstrated by the straightforward syntheses of many natural products from readily available starting materials. The efficiency of these processes nicely complements the described cationic polyolefin cyclisations and even suggests that modern radical methods provide means to improve upon nature's synthetic pathways.

  11. Superspecial radical%超特殊根

    Institute of Scientific and Technical Information of China (English)

    于淑兰

    2001-01-01

    定义了超特殊根,即由无零因子的绝对半素环类所确定的上根,并证明了它是一个特殊根。%The superspecial radical is defined, it is the upper radical, determined by the rings class consisted without divisors of zero and absolutely semiprings. And it is a special radical.

  12. Neurotoxins: Free Radical Mechanisms and Melatonin Protection

    OpenAIRE

    2010-01-01

    Toxins that pass through the blood-brain barrier put neurons and glia in peril. The damage inflicted is usually a consequence of the ability of these toxic agents to induce free radical generation within cells but especially at the level of the mitochondria. The elevated production of oxygen and nitrogen-based radicals and related non-radical products leads to the oxidation of essential macromolecules including lipids, proteins and DNA. The resultant damage is referred to as oxidative and nit...

  13. Radical-free biology of oxidative stress

    OpenAIRE

    2008-01-01

    Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the “redox hypothesis,” is that oxidative stress occurs as a consequence of disruption of thi...

  14. Photodynamically generated bovine serum albumin radicals

    DEFF Research Database (Denmark)

    Silvester, J A; Timmins, G S; Davies, Michael Jonathan

    1998-01-01

    Porphyrin-sensitized photoxidation of bovine serum albumin (BSA) results in oxidation of the protein at (at least) two different, specific sites: the Cys-34 residue giving rise to a thiyl radical (RS.); and one or both of the tryptophan residues (Trp-134 and Trp-214) resulting in the formation of...... of proteases. The generation of protein-derived radicals also results in an enhancement of photobleaching of the porphyrin, suggesting that protein radical generation is linked to porphyrin photooxidation....

  15. Formation of free radicals during phacoemulsification.

    Science.gov (United States)

    Holst, A; Rolfsen, W; Svensson, B; Ollinger, K; Lundgren, B

    1993-04-01

    During phacoemulsification cavitation bubbles are formed. These bubbles are believed to be one source of damage to corneal endothelium seen after phacoemulsification. Free radicals are induced whenever cavitation bubbles implode. The aim of this study was to confirm the initiation of free radicals by phacoemulsification and to correlate the power of ultrasound in the phacoemulsification process to the amount of free radicals formed, using both in vitro and in vivo techniques. The formation of free radicals was determined by adding luminol to a buffer and measuring the chemoluminescence in vitro and in rabbit eyes (Lumacounter 2080 or a single-photon-counting apparatus) during phacoemulsification. The data obtained show that free radicals are formed during phacoemulsification and that the amount of free radicals correlates with the power of ultrasound. Furthermore, the radical formation could be inhibited by the radical scavengers SOD, Healon and Healon GV. These results were achieved both in vitro in the test tube and in vivo in rabbit eyes. By showing that the addition of SOD to the irrigation buffer during phacoemulsification decreases the corneal endothelial cell damage, we show that free radicals could have a role in postoperative complications seen clinically.

  16. Near-Ring Radicals and Class Pairs

    Institute of Scientific and Technical Information of China (English)

    L.Godloza; N.J.Groenewald; W.A.Olivier

    2005-01-01

    For near-ring ideal mappings p1 and p2, we investigate radical theoretical properties of and the relationship among the class pairs (p1: p2), (Sp2: Sp1) and (Rp2:Rp1). Conditions on p1 and p2 are given for a general class pair to form a radical class of various types. These types include the Plotkin and KA-radical varieties. A number of examples are shown to motivate the suitability of the theory of Hoehnke-radicals over KA-radicals when radical pairs of near-rings are studied. In particular, it is shown that (pc: P3) forms a KA-radical class, where Pc denotes the class of completely prime nearrings and P3 the class of 3-prime near-rings. This gives another near-ring generalization of the 2-primal ring concept. The theory of radical pairs are also used to show that in general the class of 3-semiprime near-rings is not the semisimple class of the 3-prime radical.

  17. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-08-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of narrow mental states; that is, the idea that the mental content of an individual can be fully characterised without any reference external to her or him. I show that this fact imposes some severe restrictions to SIS to be incorporated into RC. In particular, I argue that only qualitative studies can comply with the requirement of narrowness. Nevertheless, I propose that quantitative works can be employed as sources of types in order to study token actual students. I use this type-token dichotomy to put forward an outline of a theory of the relation between school contents and mental contents. In this view, token mental contents regarding a given topic can be defined, and probed, only by resorting to typical school contents.

  18. Iron and iron derived radicals

    Energy Technology Data Exchange (ETDEWEB)

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

  19. Photoionisation of the tropyl radical

    Directory of Open Access Journals (Sweden)

    Kathrin H. Fischer

    2013-04-01

    Full Text Available We present a study on the photoionisation of the cycloheptatrienyl (tropyl radical, C7H7, using tunable vacuum ultraviolet synchrotron radiation. Tropyl is generated by flash pyrolysis from bitropyl. Ions and electrons are detected in coincidence, permitting us to record mass-selected photoelectron spectra. The threshold photoelectron spectrum of tropyl, corresponding to the X+ 1A1’ ← X 2E2” transition, reveals an ionisation energy of 6.23 ± 0.02 eV, in good agreement with Rydberg extrapolations, but slightly lower than the value derived from earlier photoelectron spectra. Several vibrations can be resolved and are reassigned to the C–C stretch mode ν16+ and to a combination of ν16+ with the ring breathing mode ν2+. Above 10.55 eV dissociative photoionisation of tropyl is observed, leading to the formation of C5H5+ and C2H2.

  20. Production and contribution of hydroxyl radicals between the DSA anode and water interface

    Institute of Scientific and Technical Information of China (English)

    Guoting Li; Meiya Zhu; Jing Chen; Yunxia Li; Xiwang Zhang

    2011-01-01

    Hydroxyl radicals play the key role during electrochemical oxidation and photoelectrochemical oxidation. The production and effect of hydroxyl radicals on the interface between DSA anode and water was investigated by examining the quenching effect of iso-propanol on Orange Ⅱ decolorization. We observed that with an increase in electrode potential from 4 to 12 V across electrodes at pH 7.0, the contribution percentage of hydroxyl radicals increased dramatically. More OH radicals were produced in acidic and alkaline conditions than at neutral conditions. At electrode potential of 4 V, the contribution percentage of hydroxyl radicals was obviously higher at near neutral pH conditions, while removal efficiency of Orange Ⅱ achieved was the lowest concurrently. Finally, for photocatalytic oxidation,electrochemical oxidation, and photoelcctrochemical oxidation using the same DSA electrode, the effect of hydroxyl radicals proved to be dominant in photocatalytic oxidation but the contribution of hydroxyl radicals was not dominant in electrochemical oxidation,which implies the necessity of UV irradiation for electrochemical oxidation during water treatrnent.

  1. Interaction of radiation-generated free radicals with collagen and metalloproteins using cesium-137 gamma source

    Science.gov (United States)

    Shieh, James J.; Wierbicki, Eugen

    The interaction of collagen and metalloproteins with radiation-generated radicals has been studied using spectrophotometric, chromatographic, and ESR techniques. The hydroxyl radical (·OH) reacted with and caused polymerization of acid soluble collagen. Similar reactions were also observed in a ferrimyoglobin and cytochrome C system. Insoluble collagen from bovine muscle subjected to radiation is followed by a first-order process for the decay of free radicals, depending on relative humidity of the system. When the samples were irradiated with 3 kGy at 25°C by a Cesium-137 Irradiator, the observed half life (hr) of free radicals in the samples decreased with increase of relative humidity RH: 31% > 69% > 100%. When collagen, previously kept dry or under 31% RH, was irradiated with 3 kGy at 77°K (-196°C), the decay of free radicals reached a plateau with annealing at -120°C or higher. The decay kept decreasing with annealing at -100°C or higher temperature when collagen maintained at 69 and 100% RH was used. It is concluded that the free radicals in moistened collagen from bovine muscle decreased at a higher rate than in dried collagen. This suggests that free radicals may persist for a longer period of time in irradiated dry proteins of food or animal feed than in foods of higher moisture extent.

  2. Development of nitroxide radicals-containing polymer for scavenging reactive oxygen species from cigarette smoke

    Science.gov (United States)

    Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

    2014-06-01

    We developed a nitroxide radicals-containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV-visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke.

  3. Photoinduced hydroxyl radical and photocatalytic activity of samarium-doped TiO(2) nanocrystalline.

    Science.gov (United States)

    Xiao, Qi; Si, Zhichun; Zhang, Jiang; Xiao, Chong; Tan, Xiaoke

    2008-01-15

    Sm(3+)-doped TiO(2) nanocrystalline has been prepared by sol-gel auto-combustion technique and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, and also UV-vis diffuse reflectance spectroscopy (DRS). These Sm(3+)-doped TiO(2) samples were tested for methylene blue (MB) decomposition and *OH radical formation. The analysis of *OH radical formation on the sample surface under UV irradiation was performed by fluorescence technique with using terephthalic acid, which readily reacted with *OH radical to produce highly fluorescent product, 2-hydroxyterephthalic acid. It was observed that the presence of Sm(3+) ion as a dopant significantly enhanced the photocatalytic activity for MB degradation under UV light irradiation because both the larger specific surface area and the greater the formation rate of *OH radical were simultaneously obtained for Sm(3+)-doped TiO(2) nanocrystalline. The adsorption experimental demonstrated that Sm(3+)-TiO(2) had a higher MB adsorption capacity than undoped TiO(2) and the adsorption capacity of MB increased with the increase of samarium ion content. The results also indicated that the greater the formation rate of *OH radical was, the higher photocatalytic activity was achieved. In this study, the optimum amount of Sm(3+) doping was 0.5 mol%, at which the recombination of photo-induced electrons and holes could be effectively inhibited, the highest formation rate of *OH radicals was, and thereby the highest photocatalytic activity was achieved.

  4. Hydroxyl radical reaction with trans-resveratrol: initial carbon radical adduct formation followed by rearrangement to phenoxyl radical.

    Science.gov (United States)

    Li, Dan-Dan; Han, Rui-Min; Liang, Ran; Chen, Chang-Hui; Lai, Wenzhen; Zhang, Jian-Ping; Skibsted, Leif H

    2012-06-21

    In the reaction between trans-resveratrol (resveratrol) and the hydroxyl radical, kinetic product control leads to a short-lived hydroxyl radical adduct with an absorption maximum at 420 nm and a lifetime of 0.21 ± 0.01 μs (anaerobic acetonitrile at 25 °C) as shown by laser flash photolysis using N-hydroxypyridine-2(1H)-thione (N-HPT) as a "photo-Fenton" reagent. The transient spectra of the radical adduct are in agreement with density functional theory (DFT) calculations showing an absorption maximum at 442 or 422 nm for C2 and C6 hydroxyl adducts, respectively, and showing the lowest energy for the transition state leading to the C2 adduct compared to other radical products. From this initial product, the relative long-lived 4'-phenoxyl radical of resveratrol (τ = 9.9 ± 0.9 μs) with an absorption maximum at 390 nm is formed in a process with a time constant (τ = 0.21 ± 0.01 μs) similar to the decay constant for the C2 hydroxyl adduct (or a C2/C6 hydroxyl adduct mixture) and in agreement with thermodynamics identifying this product as the most stable resveratrol radical. The hydroxyl radical adduct to phenoxyl radical conversion with concomitant water dissociation has a rate constant of 5 × 10(6) s(-1) and may occur by intramolecular hydrogen atom transfer or by stepwise proton-assisted electron transfer. Photolysis of N-HPT also leads to a thiyl radical which adds to resveratrol in a parallel reaction forming a sulfur radical adduct with a lifetime of 0.28 ± 0.04 μs and an absorption maximum at 483 nm.

  5. Spectroscopic characterization of mechanisms of oxidation of Phe by SO4- radical: A pulse radiolysis study

    Institute of Scientific and Technical Information of China (English)

    储高升; 韩镇辉; 都志文; 张淑娟; 姚思德; 张志成

    2002-01-01

    By using time-resolved kinetic spectrophotometry and pulse radiolysis technique, the oxidation of Phe by SO4- radical has been investigated both in aqueous and water/acetonitrilemixed solutions. The results reveal that attack of the oxidizing SO4- radical on Phe leads directlyto the formation of Phe cation radical 3 with a strong absorption peak at 310 nm, then it proceeds in three competitive reactions via either hydroxylation, deprotonation or decarboxylation, which were found to be strongly dependent upon the ionization state of the substitutes -COOH and -NH2 and the nature of the solvents. Decarboxylation takes place only when the carboxyl group is deprotonated. At high pH deprotonation of Phe cation radical 3 is much easier to occur than that in neutral or acid solutions. Moreover, with addition of acetonitrile, deprotonation is more predominant than hydroxylation, whereas in aqueous solutions hydroxylation is much easier to occur.

  6. Spectroscopic characterization of mechanisms of oxidation of Phe by SO.-4 radical: A pulse radiolysis study

    Institute of Scientific and Technical Information of China (English)

    储高升; 张淑娟; 姚思德; 韩镇辉; 都志文; 张志成

    2002-01-01

    By using time-resolved kinetic spectrophotometry and pulse radiolysis technique, the oxidation of Phe by radical has been investigated both in aqueous and water/acetonitrile mixed solutions. The results reveal that attack of the oxidizing SO4-radical on Phe leads directly to the formation of Phe cation radical 3 with a strong absorption peak at 310 nm, then it proceeds in three competitive reactions via either hydroxylation, deprotonation or decarboxylation, which were found to be strongly dependent upon the ionization state of the substitutes -COOH and -NH2 and the nature of the solvents. Decarboxylation takes place only when the carboxyl group is deprotonated. At high pH deprotonation of Phe cation radical 3 is much easier to occur than that in neutral or acid solutions. Moreover, with addition of acetonitrile, deprotonation is more predominant than hydroxylation, whereas in aqueous solutions hydroxylation is much easier to occur.

  7. Ischemia/reperfusion mediated oxygen free radical production in rat brain endothelium

    Energy Technology Data Exchange (ETDEWEB)

    Grammas, P.; Wood, K. (Univ. of Oklahoma, Oklahoma City (United States)); Liu, G.J.; Floyd, R.A. (Oklahoma Medical Research Foundation, Oklahoma City (United States)); Wood, K. (Univ. of Oklahoma Health Sciences Center, Oklahoma City (United States) Oklahoma Medical Research Foundation, Oklahoma City (United States))

    1991-03-11

    Oxygen free radicals have been increasingly implicated in ischemia/reperfusion mediated injury to tissue. Recent methods of assessing tissue oxygen free radical flux including spin trapping, salicylate hydroxylation, protein oxidation and specific enzymatic activity loss have clearly shown that ischemia/reperfusion mediates oxidative damage in brain. Vascular endothelia cells are increasingly implicated in inactivating oxidative damage. The authors have used salicylate to assess hydroxyl free radical flux during an anoxia-reoxygenation insult in isolated brain microvessels. Brain microvessels that were subjected to a 20 min anoxia period and then reoxygenated for 20 min hydroxylated salicylate to form tissue localized 2,3-dihydroxybenzoic acid (2,3-DHBA) whereas microvessels that remained oxygenated throughout contained very little 2,3-DHBA. The data suggest that anoxia/reoxygenation of microvessels produces tissue localized hydroxyl free radical flux.

  8. Radical Behaviorism and Buddhism: Complementarities and Conflicts

    Science.gov (United States)

    Diller, James W.; Lattal, Kennon A.

    2008-01-01

    Comparisons have been made between Buddhism and the philosophy of science in general, but there have been only a few attempts to draw comparisons directly with the philosophy of radical behaviorism. The present review therefore considers heretofore unconsidered points of comparison between Buddhism and radical behaviorism in terms of their…

  9. Resonance raman studies of phenylcyclopropane radical cations

    NARCIS (Netherlands)

    Godbout, J.T.; Zuilhof, H.; Heim, G.; Gould, I.R.; Goodman, J.L.; Dinnocenzo, J.P.; Myers Kelley, A.

    2000-01-01

    Resonance Raman spectra of the radical cations of phenylcyclopropane and trans-1-phenyl-2-methylcyclopropane are reported. A near-UV pump pulse excites a photosensitizer which oxidizes the species of interest, and a visible probe pulse delayed by 35 ns obtains the spectrum of the radical ion. The tr

  10. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.

    2011-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.

  11. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.

    2013-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.

  12. Organic chemistry: A radical step forward

    Science.gov (United States)

    Zhang, Wenhao; Li, Ang

    2017-02-01

    Free radicals are notorious for unselective coupling reactions; however, the coupling of free radicals generated from acyl tellurides has now been shown to form C-C bonds with remarkable fidelity, which enables easy one-step assembly of densely oxygenated natural product motifs.

  13. Radical-Local Teaching and Learning

    DEFF Research Database (Denmark)

    Hedegaard, Mariane; Chaiklin, Seth

    radical-local teaching and learning approach. The first half of the book introduces the idea of radical-local teaching and learning and develops the theoretical background for this perspective, drawing on the cultural-historical research tradition, particularly from Vygotsky, El'konin, Davydov...

  14. Victimology: A Consideration of the Radical Critique.

    Science.gov (United States)

    Friedrichs, David O.

    1983-01-01

    Discusses the emergence of a new radical model in criminology and a new subdisciplinary area of concern, victimology, with roots in Marx and Engels' original formulations. Argues that the radical understanding of victimization provides an important corrective to mainstream approaches and broadens the focus of the concept of victimization. (JAC)

  15. Localization versus delocalization in diamine radical cations

    DEFF Research Database (Denmark)

    Brouwer, A.M.; Wiering, P.G.; Zwier, J.M.;

    1997-01-01

    The optical absorption spectrum of the radical cation of 1,4-diphenylpiperazine 2a shows a strong transition in the near-IR, and only a weak band at 445 nm, in the region where aniline radical cations normally absorb strongly. This indicates that the charge and spin are delocalized over the two...

  16. Free Radical Mechanisms in Autoxidation Processes.

    Science.gov (United States)

    Simic, Michael G.

    1981-01-01

    Discusses the use of steady-state radiation chemistry and pulse radiolysis for the generation of initial free radicals and formation of peroxy radicals in the autoxidation process. Provides information regarding the autoxidation process. Defines autoxidation reactions and antioxidant action. (CS)

  17. Place of Schauta's radical vaginal hysterectomy.

    Science.gov (United States)

    Roy, Michel; Plante, Marie

    2011-04-01

    Women affected by early stage invasive cancer of the cervix are usually treated by surgery. Radical abdominal hysterectomy with pelvic lymphadenectomy is the most widely used technique. Because the morbidity of the abdominal approach can be important, the radical vaginal hysterectomy has gained acceptance in gynaecologic oncology. New instrumentation in laparoscopy also opens the possibility of treating cervical cancer by laparoscopically assisted vaginal radical hysterectomy and also total laparoscopic radical hysterectomy. Before these techniques become widely accepted, it has to be shown that safety and efficacy are comparable with the 'standard' abdominal approach. In this chapter, we review the technique of radical vaginal hysterectomy with pelvic lymphadenectomy and evaluate results of published studies, comparing the abdominal, vaginal and laparoscopic approaches.

  18. Determination of hydroxyl radical in organic wastewater treatment by electrochemical oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; YU Xiu-juan; SUN De-zhi

    2008-01-01

    A method of detection hydroxyl radical (·OH) produced by electrochemical oxidation in organic wastewater treatment was developed. Benzoic acid with weak fluorescence may reacted with hydroxyl radical to produce 3-hydroxybenzonic acid with intense fluorescence, whose characteristic fluorescence excitation and e-mission wavelength were at 305 nm and 410 nm. The 3-hydroxybenzonic acid was separated from electrochemi-cal oxidation system by HPLC. Two major hydroxylated products were quantified corresponding to 3-hydroxyben-zonic, 4-hydroxybenzonic acid. Therefore the quantity of hydroxyl radical in the reactive system should be pri-marily calculated. The optimal experimental program was obtained by studying the determination conditions, which were benzoic acid of 1.0 mmol/L, electrolysis time of 60 min, current density of 39 mA/cm2, supporting electrolyte (Na2SO4) of 0.02 mol/L, and the low rate of sparged-air of 25 mL/s. The results show that this method is stable, simple and rapid and can be used as a convenient method for the determination of hydroxyl radical.

  19. Concerted effects of substituents in the reaction of •OH radicals with aromatics: The hydroxybenzaldehydes

    Science.gov (United States)

    Albarran, Guadalupe; Mendoza, Edith; Schuler, Robert H.

    2016-07-01

    In the present work, we have examined the distribution of products in the radiolytic hydroxylation of 2-, 3- and 4-hydroxybenzaldehyde to obtain information on the concerted effect of the -CHO and -OH groups at the addition site of •OH radicals. The •OH radical was found to selectively add to the free positions of the aromatic ring. Furthermore, the •OH radical reacts by substitution at the ipso position followed by elimination of the substituent, producing dihydroxybenzene compounds. Additionally, the formation of carboxylic acids as an initial product has been conclusively identified by retention times and UV and mass spectra. These acids are formed as a result of the radiolytic oxidation of the initial radical formed by the addition reaction of the •OH radicals to the meso position (exocyclic carbon). The identification of the products, dihydroxybenzaldehydes, dihydroxybenzenes and hydroxybenzoic acids and calculation of their yields were achieved through HPLC. The G values of each product are given, which reflect the charge distributions in the hydroxybenzaldehydes, such that the formyl group modifies the ortho-para directing effect of the -OH substituent. The 3 and 5 positions in 2- and 4-hydroxybenzaldehyde showed increased the electronic density compared to that of phenol, indicating that the formyl group has a significant effect on the electronic structure of those hydroxybenzaldehydes. In 3-hydroxybenzaldehyde, the -OH substituent had a dominant ortho-directing effect similar to that observed for phenol.

  20. 柠檬酸提取海带渣中多糖及其抗氧化活性与结构的研究%The extraction of polysaccharide from Laminaria japonica residue by citric acid and study on antioxidant activities and structural characteristics

    Institute of Scientific and Technical Information of China (English)

    卢茳虹; 林宗毅; 崔春; 游丽君; 赵谋明

    2012-01-01

    以海带渣为原料,采用柠檬酸提取法提取海带渣中多糖,并与直接柠檬酸提取的海带多糖进行抗氧化活性与结构比较。研究表明,海带渣多糖的提取率为7.00%±0.03%,其抗氧化活性与直接酸提的海带多糖相当,具有较好的氧自由基清除能力(ORAC值为130.13μmol Trolox/g)、DPPH自由基清除能力(18.89μmol Trolox/g)、ABTS自由基清除能力(53.58μmol Trolox/g)和还原力(37.56μmol Trolox/g),其中ORAC值比抗氧剂BHT高2倍。所得海带渣多糖的主要组分分子量为310182u(2.73%)和30515u(97.27%)。红外光谱图分析表明海带渣多糖与直接酸提的海带多糖结构相似。%Laminaria japonica residue was used as the material to obtain polysaccharide by the citric acid extraction,and the antioxidant activities and structural characteristics of the polysaccharide had been compared with those of polysaccharide obtained by direct citric acid extraction. The results showed that the yield of the polysaccharide was 7.00% ± 0.03%, and the antioxidant activities were similar with those of polysaccharide obtained by direct citric acid extraction, with the values of oxygen radical absorbance capacity, DPPH radical scavenging activity, ABTS radical scavenging activity and reducing power of 130.13μmol Trolox/g, 18.89μmol Trolox/g ,53.58μmol Trolox/g and 37.56μmol Trolox/g, respectively.Moreover,the value of ORAC was 2 times higher than that of BHT. Gel permeation chromatography analysis indicated that the polysaccharide comprised two components, the molecular weights were 310 ] 82 u ( 2.73 % ) and 305 ] 5 u (97.27 % ) separately.The infrared ( I R ) spectra analysis demonstrated that the polysaccharide had resemblant structure with that obtained by direct citric acid extraction.

  1. Site reactivity in the free radicals induced damage to leucine residues: a theoretical study.

    Science.gov (United States)

    Medina, M E; Galano, A; Alvarez-Idaboy, J R

    2015-02-21

    Several recent computational studies have tried to explain the observed selectivity in radical damage to proteins. In this work we use Density Functional Theory and Transition State Theory including tunnelling corrections, reaction path degeneracy, the effect of diffusion, and the role of free radicals to get further insights into this important topic. The reaction between a leucine derivative and free radicals of biological significance, in aqueous and lipid media, has been investigated. Both thermochemical and kinetic analyses, in both hydrophilic and hydrophobic environments, have been carried out. DPPH, ˙OOH, ˙OOCH3, ˙OOCH2Cl, ˙OOCHCl2 and ˙OOCHCH2 radicals do not react with the target molecule. The reactions are proposed to be kinetically controlled. The leucine gamma site was the most reactive for the reactions with ˙N3, ˙OOCCl3, ˙OCH3, ˙OCH2Cl, and ˙OCHCl2 radicals, with rate constants equal to 1.97 × 10(5), 3.24 × 10(4), 6.68 × 10(5), 5.98 × 10(6) and 8.87 × 10(8) M(-1) s(-1), respectively, in aqueous solution. The ˙Cl, ˙OH and ˙OCCl3 radicals react with leucine at the beta, gamma, and delta positions at rates close to the diffusion limit with the alpha position which is the slowest path and the most thermodynamically favored. The presented results confirm that the Bell-Evans-Polanyi principle does not apply for the reactions between amino acid residues and free radicals. Regarding the influence of the environment on the reactivity of the studied series of free radicals towards leucine residues, it is concluded that hydrophilic media slightly lower the reactivity of the studied radicals, compared to hydrophobic ones, albeit the trends in reactivity are very similar.

  2. Effect of some naturally occurring iron ion chelators on the formation of radicals in the reaction mixtures of rat liver microsomes with ADP, Fe3+ and NADPH

    Science.gov (United States)

    Minakata, Katsuyuki; Fukushima, Kazuaki; Nakamura, Masayuki; Iwahashi, Hideo

    2011-01-01

    In order to clarify the mechanism by polyphenols of protective effects against oxidative damage or by quinolinic acid of its neurotoxic and inflammatory actions, effects of polyphenols or quinolinic acid on the radical formation were examined. The ESR measurements showed that some polyphenols such as caffeic acid, catechol, gallic acid, D-(+)-catechin, L-dopa, chlorogenic acid and L-noradrenaline inhibited the formation of radicals in the reaction mixture of rat liver microsomes with ADP, Fe3+ and NADPH. The ESR measurements showed that α-picolinic acid, 2,6-pyridinedicarboxylic acid and quinolinic acid (2,3-pyridinedicarboxylic acid) enhanced the formation of radicals in the reaction mixture of rat liver microsomes with Fe3+ and NADPH. Caffeic acid and α-picolinic acid had no effects on the formation of radicals in the presence of EDTA, suggesting that the chelation of iron ion seems to be related to the inhibitory and enhanced effects. The polyphenols may exert protective effects against oxidative damage of erythrocyte membrane, ethanol-induced fatty livers, cardiovascular diseases, inflammatory and cancer through the mechanism. On the other hand, quinolinic acid may exert its neurotoxic and inflammatory effects because of the enhanced effect on the radical formation. PMID:22128221

  3. Effect of some naturally occurring iron ion chelators on the formation of radicals in the reaction mixtures of rat liver microsomes with ADP, Fe and NADPH.

    Science.gov (United States)

    Minakata, Katsuyuki; Fukushima, Kazuaki; Nakamura, Masayuki; Iwahashi, Hideo

    2011-11-01

    In order to clarify the mechanism by polyphenols of protective effects against oxidative damage or by quinolinic acid of its neurotoxic and inflammatory actions, effects of polyphenols or quinolinic acid on the radical formation were examined. The ESR measurements showed that some polyphenols such as caffeic acid, catechol, gallic acid, D-(+)-catechin, L-dopa, chlorogenic acid and L-noradrenaline inhibited the formation of radicals in the reaction mixture of rat liver microsomes with ADP, Fe(3+) and NADPH. The ESR measurements showed that α-picolinic acid, 2,6-pyridinedicarboxylic acid and quinolinic acid (2,3-pyridinedicarboxylic acid) enhanced the formation of radicals in the reaction mixture of rat liver microsomes with Fe(3+) and NADPH. Caffeic acid and α-picolinic acid had no effects on the formation of radicals in the presence of EDTA, suggesting that the chelation of iron ion seems to be related to the inhibitory and enhanced effects. The polyphenols may exert protective effects against oxidative damage of erythrocyte membrane, ethanol-induced fatty livers, cardiovascular diseases, inflammatory and cancer through the mechanism. On the other hand, quinolinic acid may exert its neurotoxic and inflammatory effects because of the enhanced effect on the radical formation.

  4. Pilot study of radical hysterectomy versus radical trachelectomy on sexual distress.

    Science.gov (United States)

    Brotto, Lori A; Smith, Kelly B; Breckon, Erin; Plante, Marie

    2013-01-01

    Radical trachelectomy, which leaves the uterus intact, has emerged as a desirable surgical option for eligible women with early-stage cervical cancer who wish to preserve fertility. The available data suggest excellent obstetrical outcomes with radical trachelectomy, and no differences in sexual responding between radical trachelectomy and radical hysterectomy. There is a need to examine the effect of radical hysterectomy on sexual distress given that it is distinct from sexual function. Participants were 34 women diagnosed with early-stage cervical cancer. The authors report 1-month postsurgery data for 29 women (radical hysterectomy group: n = 17, M age = 41.8 years; radical trachelectomy group: n = 12, M age = 31.8 years), and 6-month follow-up data on 26 women. Whereas both groups experienced an increase in sex-related distress immediately after surgery, distress continued to increase 6 months after surgery for the radical hysterectomy group but decreased in the radical trachelectomy group. There were no between-group differences in mood, anxiety, or general measures of health. The decrease in sex-related distress in the radical trachelectomy but not in the radical hysterectomy group suggests that the preservation of fertility may have attenuated sex-related distress. Care providers should counsel women exploring surgical options for cervical cancer about potential sex distress-related sequelae.

  5. The Influence of Zeolites on Radical Formation During Lignin Pyrolysis.

    Science.gov (United States)

    Bährle, Christian; Custodis, Victoria; Jeschke, Gunnar; van Bokhoven, Jeroen A; Vogel, Frédéric

    2016-09-01

    Lignin from lignocellulosic biomass is a promising source of energy, fuels, and chemicals. The conversion of the polymeric lignin to fuels and chemicals can be achieved by catalytic and noncatalytic pyrolysis. The influence of nonporous silica and zeolite catalysts, such as silicalite, HZSM5, and HUSY, on the radical and volatile product formation during lignin pyrolysis was studied by in situ high-temperature electron paramagnetic resonance spectroscopy (HTEPR) as well as GC-MS. Higher radical concentrations were observed in the samples containing zeolite compared to the sample containing only lignin, which suggests that there is a stabilizing effect by the inorganic surfaces on the formed radical fragments. This effect was observed for nonporous silica as well as for HUSY, HZSM5, and silicalite zeolite catalysts. However, the effect is far larger for the zeolites owing to their higher specific surface area. The zeolites also showed an effect on the volatile product yield and the product distribution within the volatile phase. Although silicalite showed no effect on the product selectivity,