2,4,6-Trichlorophenylhydrazine Schiff bases as DPPH radical and super oxide anion scavengers.

Science.gov (United States)

Khan, Khalid Mohammed; Shah, Zarbad; Ahmad, Viqar Uddin; Khan, Momin; Taha, Muhammad; Rahim, Fazal; Ali, Sajjad; Ambreen, Nida; Perveen, Shahnaz; Choudhary, M Iqbal; Voelter, Wolfgang

2012-05-01

Syntheses of thirty 2,4,6-trichlorophenylhydrazine Schiff bases 1-30 were carried out and evaluated for their in vitro DPPH radical and super oxide anion scavenging activities. Compounds 1-30 have shown a varying degree of DPPH radical scavenging activity and their IC50 values range between 4.05-369.30 µM. The compounds 17, 28, 18, 14, 8, 15, 12, 2, 29, and 7 exhibited IC50 values ranging between 4.05±0.06-24.42±0.86 µM which are superior to standard n-propylgallate (IC50=30.12±0.27 µM). Selected compounds have shown a varying degree of superoxide anion radical scavenger activity and their IC50 values range between 91.23-406.90 µM. The compounds 28, 8, 17, 15, and 14, showed IC50 values between 91.23±1.2-105.31±2.29 µM which are superior to standard n-propylgallate (IC50=106.34±1.6 µM).

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase

Directory of Open Access Journals (Sweden)

Abrahim Noor

2012-11-01

Full Text Available Abstract Background Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. Methods The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase assays in MCF-7 cells. Results Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml. Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Conclusions Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase.

Science.gov (United States)

Abrahim, Noor Nazirahanie; Kanthimathi, M S; Abdul-Aziz, Azlina

2012-11-15

Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane) and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase) assays in MCF-7 cells. Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml). Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide dismutase in the treated cells could alter the antioxidant defense

Caveolin-1 sensitizes cisplatin-induced lung cancer cell apoptosis via superoxide anion-dependent mechanism.

Science.gov (United States)

Pongjit, Kanittha; Chanvorachote, Pithi

2011-12-01

Caveolin-1 (Cav-1) expression frequently found in lung cancer was linked with disease prognosis and progression. This study reveals for the first time that Cav-1 sensitizes cisplatin-induced lung carcinoma cell death by the mechanism involving oxidative stress modulation. We established stable Cav-1 overexpressed (H460/Cav-1) cells and investigated their cisplatin susceptibility in comparison with control-transfected cells and found that Cav-1 expression significantly enhanced cisplatin-mediated cell death. Results indicated that the different response to cisplatin between these cells was resulted from different level of superoxide anion induced by cisplatin. Inhibitory study revealed that superoxide anion inhibitor MnTBAP could inhibit cisplatin-mediated toxicity only in H460/Cav-1 cells while had no effect on H460 cells. Further, superoxide anion detected by DHE probe indicated that H460/Cav-1 cells generated significantly higher superoxide anion level in response to cisplatin than that of control cells. The role of Cav-1 in regulating cisplatin sensitivity was confirmed in shRNA-mediated Cav-1 down-regulated (H460/shCav-1) cells and the cells exhibited decreased cisplatin susceptibility and superoxide generation. In summary, these findings reveal novel aspects regarding role of Cav-1 in modulating oxidative stress induced by cisplatin, possibly providing new insights for cancer biology and cisplatin-based chemotherapy.

Superoxide radical (O2-) reactivity with respect to glutathione

International Nuclear Information System (INIS)

Sekaki, A.; Gardes-Albert, M.; Ferradini, C.

1984-01-01

Influence of superoxide radicals formed during gamma irradiation of glutathione in aerated aqueous solutions is examined. Solutions are buffered at pH7 and contain sodium formate for capture of H and OH radicals which are transformed in COO - radicals and then O 2 - radicals. G value of glutathione disparition vs glutathione concentration are given with and without enzyme or catalase. Reaction mechanism are interpreted [fr

Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

International Nuclear Information System (INIS)

Lespade, Laure

2016-01-01

Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH · or ABTS ·+ is explained. - Abstract: Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car–Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

Energy Technology Data Exchange (ETDEWEB)

Lespade, Laure, E-mail: l.lespade@ism.u-bordeaux1.fr

2016-08-22

Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH{sup ·} or ABTS{sup ·+} is explained. - Abstract: Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car–Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

ESR study of the anion radicals of 5-nitropyrimidines: conversion to iminoxy radicals

International Nuclear Information System (INIS)

Sevilla, M.D.; Clark, C.; Failor, R.

1976-01-01

The anion radicals of a number of 5-nitropyrimidines have been investigated by ESR spectroscopy. The anions are formed by electrolysis in dimethylformamide and by electron attachment in aqueous glasses, 12 M LiCl--D 2 O and 8 M NaOD. The electrolysis of 5-nitrouracil and 5-nitro-6-methyluracil results in relatively stable anion radicals. The results for 5-nitrouracil give evidence for two or perhaps three anions which differ only by the degree of ring nitrogen protonation. The results for 5-nitro-6-methyluracil suggest that the nitro group of the anion is twisted so that it is coupled only weakly to the ring π-electron system. The anions of 5-nitrouracil, 5-nitroorotic acid, 5-nitrobarbituric acid, and 5-nitro-6-methyluracil have been produced in the alkaline and neutral aqueous glasses. The anisotropic spectra found have been analyzed with the aid of computer simulations which assume axial symmetry. For example, the analysis of the spectrum of 5-nitrouracil anion in 12 M LiCl yields A/sub parallel//sup N/ = 33; A/sub perpendicular to//sup N/ = 5, a 6 /sup H/ = 5.5 G, g/sub parallel/ = 2.0016, and g/sub perpendicular to/ = 2.0059. A concentration dependence in the splittings is noted and discussed. Ultraviolet photolysis of the anions of 5-nitro-6-methyluracil and 5-nitrobarbituric acid results in the formation of iminoxy radicals. Mechanisms of formation of the iminoxy radicals are discussed and results found in this work are compared to results found in single crystals and aqueous solution

Pyrrolidine dithiocarbamate inhibits superoxide anion-induced pain and inflammation in the paw skin and spinal cord by targeting NF-κB and oxidative stress.

Science.gov (United States)

Pinho-Ribeiro, Felipe A; Fattori, Victor; Zarpelon, Ana C; Borghi, Sergio M; Staurengo-Ferrari, Larissa; Carvalho, Thacyana T; Alves-Filho, Jose C; Cunha, Fernando Q; Cunha, Thiago M; Casagrande, Rubia; Verri, Waldiceu A

2016-06-01

We evaluated the effect of pyrrolidine dithiocarbamate (PDTC) in superoxide anion-induced inflammatory pain. Male Swiss mice were treated with PDTC and stimulated with an intraplantar or intraperitoneal injection of potassium superoxide, a superoxide anion donor. Subcutaneous PDTC treatment attenuated mechanical hyperalgesia, thermal hyperalgesia, paw oedema and leukocyte recruitment (neutrophils and macrophages). Intraplantar injection of superoxide anion activated NF-κB and increased cytokine production (IL-1β, TNF-α and IL-10) and oxidative stress (nitrite and lipid peroxidation levels) at the primary inflammatory foci and in the spinal cord (L4-L6). PDTC treatment inhibited superoxide anion-induced NF-κB activation, cytokine production and oxidative stress in the paw and spinal cord. Furthermore, intrathecal administration of PDTC successfully inhibited superoxide anion-induced mechanical hyperalgesia, thermal hyperalgesia and inflammatory response in peripheral foci (paw). These results suggest that peripheral stimulus with superoxide anion activates the local and spinal cord oxidative- and NF-κB-dependent inflammatory nociceptive mechanisms. PDTC targets these events, therefore, inhibiting superoxide anion-induced inflammatory pain in mice.

Dibromine radical anion reactions with heme enzymes

International Nuclear Information System (INIS)

Gebicka, L.; Gebicki, J.L.

1996-01-01

Reactions of Br 2 radical anion with heme enzymes, catalase horseradish peroxidase, have been studied by pulse radiolysis. It has been found that Br 2 - does not react with the heme centre of investigated enzymes. Dibromine radical anion reacts with tryptophan residues of catalase without any influence on the activity of catalase. It is suggested that in pulse radiolysis studies, where horseradish peroxidase is at about tenfold excess toward Br 2 - , the enzyme is modified rather by Br 2 , than by Br 2 - . (author). 26 refs., 3 figs

Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators.

Science.gov (United States)

Fukuzumi, Shunichi; Ohkubo, Kei; Zheng, Xiang; Chen, Yihui; Pandey, Ravindra K; Zhan, Riqiang; Kadish, Karl M

2008-03-06

A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile).

Iron release from ferritin and lipid peroxidation by radiolytically generated reducing radicals

International Nuclear Information System (INIS)

Reif, D.W.; Schubert, J.; Aust, S.D.

1988-01-01

Iron is involved in the formation of oxidants capable of damaging membranes, protein, and DNA. Using 137 Cs gamma radiation, we investigated the release of iron from ferritin and concomitant lipid peroxidation by radiolytically generated reducing radicals, superoxide and the carbon dioxide anion radical. Both radicals released iron from ferritin with similar efficiencies and iron mobilization from ferritin required an iron chelator. Radiolytically generated superoxide anion resulted in peroxidation of phospholipid liposomes as measured by malondialdehyde formation only when ferritin was included as an iron source and the released iron was found to be chelated by the phospholipid liposomes

Superoxide radicals can act synergistically with hypochlorite to induce damage to proteins

DEFF Research Database (Denmark)

Hawkins, Clare Louise; Rees, Martin D; Davies, Michael Jonathan

2002-01-01

Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC(O)NClR'), ......Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC...

Sensitization of microorganisms and enzymes by radiation-induced selective inorganic radical anions

International Nuclear Information System (INIS)

Schubert, J.; Stegeman, H.

1981-01-01

Bacterial survival and enzymatic inactivation were examined following exposure to radiolytically-generated radical anions, X - 2 , where X=Cl, Br, I or CNS - . Depending on pH, radical anions react selectively or specifically with cysteine, tryptophan, tyrosine and histidine. Consequently, when one or more of these amino acids is crucial for enzymatic activity or bacterial survival and is attacked by a radical anion, a high degree or radiosensitization may be realized. Halide radical anions can form free chlorine, bromine or iodine. However, these bactericidal halogens are destroyed by reaction with the hydrated electron, e - sub(aq), or at pHs>9, as occurs, for example, when a medium saturated with nitrous oxide, N 2 O, and e - sub(aq) scavenger, is replaced by nitrogen or oxygen. Increasing concentration of other e - sub(aq) scavengers, such as phosphate buffer, promotes formation of halogen from halides. The conditions producing formation and elimination of halogens in irradiated media must be appreciated to avoid confusing radiosensitization by X 2 to X - 2 . Radiosensitization by radical anions of several microorganisms: S. faecalis, S. typhimurium, E. coli, and M. radiodurens is described. A crucial amino acid for survival of S. faecalis appears to be tyrosine, while both tyrosine and tryptophan seem essential for recovery of S. typhimurium from effects of ionizing radiation. It is postulated that the radiosensitizing action of radical anions involves inhibition of DNA repair of strand-breaks by depriving the cells of energy. In view of the high OH scavenging power of foods, it is concluded that the radiosensitization of bacteria and enzymes in foods by radical anions, except for special cases, is not practical. Rather, radical anions serve to identify crucial amino acids to radiosensitization mechanisms in model systems, and possibly in radiotherapy. (author)

Zwitterion radicals and anion radicals from electron transfer and solvent condensation with the fingerprint developing agent ninhydrin.

Science.gov (United States)

Schertz, T D; Reiter, R C; Stevenson, C D

2001-11-16

Ninhydrin (the fingerprint developing agent) spontaneously dehydrates in liquid ammonia and in hexamethylphosphoramide (HMPA) to form indantrione, which has a sufficiently large solution electron affinity to extract an electron from the solvent (HMPA) to produce the indantrione anion radical. In liquid NH(3), the presence of trace amounts of amide ion causes the spontaneous formation of an anion radical condensation product, wherein the no. 2 carbon (originally a carbonyl carbon) becomes substituted with -NH(2) and -OH groups. In HMPA, the indantrione anion radical spontaneously forms condensation products with the HMPA to produce a variety of zwitterionic radicals, wherein the no. 2 carbon becomes directly attached to a nitrogen of the HMPA. The mechanisms for the formation of the zwitterionic paramagnetic condensation products are analogous to that observed in the reaction of ninhydrin with amino acids to yield Ruhemann's Purple, the contrast product in fingerprint development. The formation of anion and zwitterionic radical condensation products from ninhydrin and nitrogen-containing solvents may represent an example of a host of analogous polyketone-solvent reactions.

Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy

International Nuclear Information System (INIS)

Mani, Tomoyasu; Brookhaven National Laboratory; Grills, David C.

2017-01-01

Delocalization of charges is one of the factors controlling charge transport in conjugated molecules. It is considered to play an important role in the performance of a wide range of molecular technologies, including organic solar cells and organic electronics. Dimerization reactions are well-suited as a model to investigate intermolecular spatial delocalization of charges. And while dimerization reactions of radical cations are well investigated, studies on radical anions are still scarce. Upon dimerization of radical anions with neutral counterparts, an electron is considered to delocalize over the two molecules. By using time-resolved infrared (TRIR) detection coupled with pulse radiolysis, we show that radical anions of 4-n-hexyl-4'-cyanobiphenyl (6CB) undergo such dimerization reactions, with an electron equally delocalized over the two molecules. We have recently demonstrated that nitrile ν(C≡N) vibrations respond to the degree of electron localization of nitrile-substituted anions: we can quantify the changes in the electronic charges from the neutral to the anion states in the nitriles by monitoring the ν(C≡N) IR shifts. In the first part of this article, we show that the sensitivity of the ν(C≡N) IR shifts does not depend on solvent polarity. In the second part, we describe how probing the shifts of the nitrile IR vibrational band unambiguously confirms the formation of dimer radical anions, with K dim = 3 × 10 4 M –1 . IR findings are corroborated by electronic absorption spectroscopy and electronic structure calculations. We find that the presence of a hexyl chain and the formation of π–π interactions are both crucial for dimerization of radical anions of 6CB with neutral 6CB. Our study provides clear evidence of spatial delocalization of electrons over two molecular fragments.

Inhibition of platelet aggregation and in vitro free radical scavenging activity of dried fruiting bodies of Pleurotus eous.

Science.gov (United States)

Suseem, S R; Saral, Mary

2015-07-01

To evaluate the ethyl acetate, methanol and aqueous extracts of dried fruiting bodies of Pleurotus eous for its anti-platelet activity on human volunteer's blood. And also to analyze the free radical scavenging property of the extracts of P.eous by using various in vitro models. Anti-platelet activity of dried fruiting bodies of P.eous was evaluated by in vitro model using blood platelets. Inhibition of platelet aggregation was monitored after pre-incubation of platelets with the crude extracts of mushroom P.eous. Antioxidant activities of extracts of P.eous were evaluated by different in vitro experiments, namely, 1, 1-diphenyl-2-picryl hydrazyl (DPPH), superoxide, hydroxyl radical and lipid peroxide radical models. Crude extracts of mushroom P.eous inhibited platelet aggregation dose-dependently which was induced by adenosine diphosphate (ADP). At a maximum concentration of 10 mg/mL, methanol extract effected 64.02% inhibition of lipid per-oxidation and 50.12% scavenging effect on superoxide anion radical. Aqueous extract of P.eous have shown 69.43% chelating ability on ferrous ions, 24.27% scavenging effect on hydroxyl radical and 49.57% scavenging effect on DPPH radical at 10 mg/mL. Increasing concentrations of the extract were found to cause progressively decreasing of the intensity of absorbance. Anti-platelet effects could be related in part to the polyphenolic compounds present in the extracts. Antioxidant activity results indicated the free radical scavenging property of the extracts of P.eous which might be due to the high content of phenolic compounds and flavonoids.

Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes.

Science.gov (United States)

Heyno, Eiri; Mary, Véronique; Schopfer, Peter; Krieger-Liszkay, Anja

2011-07-01

Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.

Radiolytic reduction of nifurtimose by CO2-· free radicals

International Nuclear Information System (INIS)

Filali-Mouhim, A.; Champion, B.; Jore, D.; Ferradini, C.; Hickel, B.

1991-01-01

Nifurtimox is an antiparasitic drug often used in the treatment of the Chagas disease. Its therapeutic action seems to involve its monoelectronic reduction leading to a reduced radical capable of providing superoxide anion by reaction with oxygen. The oxidation reduction mechanisms involved in this action have been studied by steady state and pulse radiolysis methods. This study is devoted to the monoelectronic exchanges observed in the absence of air, the reducing radicals being the CO 2 - · anions [fr

Anion photoelectron spectroscopy of radicals and clusters

Energy Technology Data Exchange (ETDEWEB)

Travis, Taylor R. [Univ. of California, Berkeley, CA (United States)

1999-12-01

Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying ²Σ and ²π states of C_2nH (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C₂H and C₄H. Other radicals studied include NCN and I₃. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I₃ revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

[Involvement of carbonate/bicarbonate ions in the superoxide-generating reaction of adrenaline autoxidation].

Science.gov (United States)

Sirota, T V

2015-01-01

An important role of carbonate/bicarbonate ions has been recognized in the superoxide generating reaction of adrenaline autooxidation in an alkaline buffer (a model of quinoid adrenaline oxidation in the body). It is suggested that these ions are directly involved not only in formation of superoxide anion radical (О(2)(-)) but also other radicals derived from the carbonate/bicarbonate buffer. Using various buffers it was shown that the rate of accumulation of adrenochrome, the end product of adrenaline oxidation, and the rate of О(2)(-)· formation depend on concentration of carbonate/bicarbonate ions in the buffer and that these ions significantly accelerate adrenaline autooxidation thus demonstrating prooxidant properties. The detectable amount of diformazan, the product of nitro blue tetrazolium (NBT) reduction, was significantly higher than the amount of adrenochrome formed; taking into consideration the literature data on О(2)(-)· detection by NBT it is suggested that adrenaline autooxidation is accompanied by one-electron reduction not only of oxygen dissolved in the buffer and responsible for superoxide formation but possible carbon dioxide also dissolved in the buffer as well as carbonate/bicarbonate buffer components leading to formation of corresponding radicals. The plots of the dependence of the inhibition of adrenochrome and diformazan formation on the superoxide dismutase concentration have shown that not only superoxide radicals are formed during adrenaline autooxidation. Since carbonate/bicarbonate ions are known to be universally present in the living nature, their involvement in free radical processes proceeding in the organism is discussed.

Structure and reactivity of the N-acetyl-cysteine radical cation and anion: does radical migration occur?

NARCIS (Netherlands)

Osburn, S.; Berden, G.; Oomens, J.; O'Hair, R.A.J.; Ryzhov, V.

2011-01-01

The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of

Structure and Reactivity of the N-Acetyl-Cysteine Radical Cation and Anion: Does Radical Migration Occur?

NARCIS (Netherlands)

Osburn, S.; G. Berden,; Oomens, J.; O' Hair, R. A. J.; Ryzhov, V.

2011-01-01

The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN

Science.gov (United States)

Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

2015-01-01

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions () in mitochondria, either by chemical inhibition of complex I or by genetic silencing of -dismutating mitochondrial Sod2. The -dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated -induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with , PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

Formation and disappearance of superoxide radicals in aqueous solutions

International Nuclear Information System (INIS)

Allen, A.O.; Bielski, B.H.J.

1980-01-01

A literature review of superoxide radicals in aqueous solutions is presented covering the following: history; methods of formation of aqueous HO 2 /HO 2 - by radiolysis and photolysis, electrolysis, mixing nonaqueous solutions into water, chemical reactions, enzymatic generation of O 2 - , and photosensitization; and properties of HO 2 /O 2 - in aqueous solution, which cover spontaneous dismutation rates, pk and absorption spectra, catalyzed dismutation, thermodynamics and the so-called Haber-Weiss Reaction

Radical anion structure of β-halogen-substituted acetamides in X-ray-irradiated single crystals: an INDO and EPR study

International Nuclear Information System (INIS)

Samskog, P.O.; Kispert, L.D.

1984-01-01

The anion radicals of bromodifluoroacetamide and chlorodifluoroacetamide are investigated by using the INDO method and EPR spectroscopy. INDO calculations for the anions give a spin density distribution in agreement with that suggested from experiment. Results of the analyses show that the unpaired electron occupies the sigma* orbital composed of the rho orbitals, along the C/sub β/-X bond, on the carbon and the unique halogen atoms. The results are compared to the radical anion in trifluoroacetamide. The electronic structure of SCF 2 CONH 2 - radical anions is a π-radical anion when X = F and a sigma*-radical anion when X = Cl and Br. 2 figures, 4 tables

Resonance Raman Spectrum of the Transient (SCN)2 Free Radical Anion

DEFF Research Database (Denmark)

Wilbrandt, Robert Walter; Jensen, N. H.; Pagsberg, Palle Bjørn

1979-01-01

The resonance Raman spectrum of the transient species (λmax = 475 nm, τ½ = 1.6 μs) formed by pulse radiolysis of aqueous solutions of thiocyanate, SCN2−, is reported. The spectrum is discussed in terms of the previous assignment of this transient to the radical anion, (SCN)−2. The observed...... vibrational frequencies of the radical anion are consistent with substantial weakening of the S---S and the Ctriple bond; length as m-dashN bonds are compared with neutral thiocyanogen....

Protonation Reaction of Benzonitrile Radical Anion and Absorption of Product

DEFF Research Database (Denmark)

Holcman, Jerzy; Sehested, Knud

1975-01-01

The rate constant for the protonation of benzonitrile radical anions formed in pulse radiolysis of aqueous benzonitrile solutions is (3.5 ± 0.5)× 1010 dm3 mol–1 s–1. A new 270 nm absorption band is attributed to the protonated benzonitrile anion. The pK of the protonation reaction is determined t...

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.).

Science.gov (United States)

Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo

2005-04-06

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.

Brain superoxide anion formation in immature rats during seizures: Protection by selected compounds

Czech Academy of Sciences Publication Activity Database

Folbergrová, Jaroslava; Otáhal, Jakub; Druga, Rastislav

2012-01-01

Roč. 233, č. 1 (2012), s. 421-429 ISSN 0014-4886 R&D Projects: GA ČR GA309/08/0292; GA ČR GAP303/10/0999 Institutional research plan: CEZ:AV0Z50110509 Keywords : immature rats * DL-homocysteic acid-induced seizures * superoxide anion * SOD mimetics * protection * Fluoro-Jade B staining * brain damage Subject RIV: FH - Neurology Impact factor: 4.645, year: 2012

Carbonate radical anion-induced electron transfer in bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Joshi, Ravi [Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: rjudrin@yahoo.com; Mukherjee, T. [Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2006-07-15

Reaction of native and thermally denatured bovine serum albumin (BSA) with carbonate radical anion (CO{sub 3}{sup -} radical) has been studied using pulse radiolysis technique. Scavenging of CO{sub 3}{sup -} radical by native BSA and consequent electron transfer from tyrosine to tryptophan radical has been observed to occur with almost same rate constant (k{approx}1.7x10{sup 8} dm{sup 3} mol{sup -1} s{sup -1}) at pH 8.8. Effect of structural changes, due to thermal denaturation, on scavenging of CO{sub 3}{sup -} radical and the electron transfer process have been studied and discussed in this paper.

Radical quenching by rosmarinic acid from Lavandula vera MM cell culture.

Science.gov (United States)

Kovacheva, Elena; Georgiev, Milen; Pashova, Svetlana; Angelova, Maria; Ilieva, Mladenka

2006-01-01

This study was conducted to evaluate the radical scavenging capacities of extracts and preparations from a Lavandula vera MM plant cell culture with different rosmarinic acid content and to compare them with pure rosmarinic and caffeic acids as well. The methods, which were used are superoxide anion and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals scavenging assays. Results showed that extracts and preparations from Lavandula vera MM possess strong radical scavengers, as the best both radical scavengers appeared to be the fractions with enriched rosmarinic acid content, obtained after ethylacetate fractioning (47.7% inhibition of superoxide radicals and 14.2 microM 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid equivalents, respectively). These data reveal the possibilities for application of these preparations as antioxidants.

Polysulfides and products of H2S/S-nitrosoglutathione in comparison to H2S, glutathione and antioxidant Trolox are potent scavengers of superoxide anion radical and produce hydroxyl radical by decomposition of H2O2.

Science.gov (United States)

Misak, Anton; Grman, Marian; Bacova, Zuzana; Rezuchova, Ingeborg; Hudecova, Sona; Ondriasova, Elena; Krizanova, Olga; Brezova, Vlasta; Chovanec, Miroslav; Ondrias, Karol

2018-06-01

Exogenous and endogenously produced sulfide derivatives, such as H 2 S/HS - /S 2- , polysulfides and products of the H 2 S/S-nitrosoglutathione interaction (S/GSNO), affect numerous biological processes in which superoxide anion (O 2 - ) and hydroxyl (OH) radicals play an important role. Their cytoprotective-antioxidant and contrasting pro-oxidant-toxic effects have been reported. Therefore, the aim of our work was to contribute to resolving this apparent inconsistency by studying sulfide derivatives/free radical interactions and their consequent biological effects compared to the antioxidants glutathione (GSH) and Trolox. Using the electron paramagnetic resonance (EPR) spin trapping technique and O 2 - , we found that a polysulfide (Na 2 S 4 ) and S/GSNO were potent scavengers of O 2 - and cPTIO radicals compared to H 2 S (Na 2 S), GSH and Trolox, and S/GSNO scavenged the DEPMPO-OH radical. As detected by the EPR spectra of DEPMPO-OH, the formation of OH in physiological solution by S/GSNO was suggested. All the studied sulfide derivatives, but not Trolox or GSH, had a bell-shaped potency to decompose H 2 O 2 and produced OH in the following order: S/GSNO > Na 2 S 4  ≥ Na 2 S > GSH = Trolox = 0, but they scavenged OH at higher concentrations. In studies of the biological consequences of these sulfide derivatives/H 2 O 2 properties, we found the following: (i) S/GSNO alone and all sulfide derivatives in the presence of H 2 O 2 cleaved plasmid DNA; (ii) S/GSNO interfered with viral replication and consequently decreased the infectivity of viruses; (iii) the sulfide derivatives induced apoptosis in A2780 cells but inhibited apoptosis induced by H 2 O 2 ; and (iv) Na 2 S 4 modulated intracellular calcium in A87MG cells, which depended on the order of Na 2 S 4 /H 2 O 2 application. We suggest that the apparent inconsistency of the cytoprotective-antioxidant and contrasting pro-oxidant-toxic biological effects of sulfide derivatives results from their time

Radiation-induced damage in T4 bacteriophage: the effect of superoxid radicals and molecular oxygen. Progress report, December 1, 1977--November 30, 1978

International Nuclear Information System (INIS)

Samuni, A.; Chevion, M.; Halpern, Y.S.; Ilan, Y.A.; Czapski, G.

1978-01-01

The sensitivity of T4 bacteriophage towards γ irradiation has been studied in phosphate buffer suspensions. The spectrum of the water radicals was controlled by a careful choice of the appropriate saturating gas and the addition of radical scavengers. Thus, it was possible to distinguish between the effects of molecular oxygen and the superoxide radicals formed through its reactions. About 90 percent of the damage was caused by the water radicals formed in the bulk suspensions. These probably affected the phage proteins; only the remainder of the damage involved the viral DNA. The oxygen enhancement ratio observed was not connected in any way with the formation of the superoxide radicals. The results confirmed that the OH radicals are the reactive species, while e - /sub aq/ as well as the superoxide radical do not contribute to the radiodamage

Effect of carbonyl group on the lifetimes of pentafluoroacetophenone and pentafluorobenzaldehyde radical anions in aqueous solution: a pulse radiolysis study

International Nuclear Information System (INIS)

Shoute, L.C.T.

1996-01-01

Hydrated electrons react with pentafluoroacetophenone (PFA) to form radical anion. Evidence for the formation of the radical anion was obtained from observation of intermolecular electron transfer from PFA .- to p-benzoquinone (Q) and methyl viologen (MV 2+ ) to form Q .- and MV .+ . The radical anion lose fluoride with a rate constant of 5x10 4 s -1 . The radical anion has a pK a =7.5. Radical anion of pentafluorobenzaldehyde (PFB) was observed on reduction PFB with hydrated electron. It has a pK a =7.2. It loses fluoride with a rate constant of 1.2x10 5 s -1 . The studies show that substitution of a carbonyl group in the aromatic ring of a perfluorinated compound led to dramatic increase in the lifetime of the radical anion formed on electron addition due to decrease in the rate of fluoride elimination. This led to the possibility of observing their reactions with other solute present in the solution. (author). 6 refs., 1 tab

Formation of radical anions of radiosensitizers and related model compounds via electrospray ionization

DEFF Research Database (Denmark)

Feketeová, Linda; Albright, Abigail L; Sørensen, Brita Singers

2014-01-01

Radiosensitizers are used in radiotherapy to enhance tumour control of radioresistant hypoxic tumours. While the detailed mechanism of radiosensitization is still unknown, the formation of radical anions is believed to be a key step. Thus understanding the ionization reactions of radiosensitizers......, misonidazole and related compounds using a hybrid linear ion trap – Fourier Transform Ion Cyclotron Resonance mass spectrometer (Finnigan-LTQ-FT). A key finding is that negative electrospray ionization of these radiosensitizers leads to the formation of radical anions, allowing their fragmentation reactions...

Super-pnicogen bonding in the radical anion of the fluorophosphine dimer

Science.gov (United States)

Setiawan, Dani; Cremer, Dieter

2016-10-01

The LUMO of the pnicogen-bonded fluoro-phosphine dimer has PP bonding character. Radical anion and dianion form relatively strong pnicogen bonds with some covalent character where however the dianion turns out to be a second order transition state. The binding energy of (FPH 2)2- is 30.4 kcal/mol (CCSD(T)/aug-cc-pVTZ; CASPT2(5,8): 30.7 kcal/mol) and the bond strength order measured with the local PP bond stretching force constant increases from 0.055 for the neutral dimer to 0.187 thus revealing that the stabilization of the radical anion is to a large extend a result of one-electron six-center delocalization. Pnicogen-bonded complexes have a stabilizing electron affinity.

o-Iminobenzosemiquinonate and o-imino-p-methylbenzosemiquinonate anion radicals coupled VO2+ stabilization.

Science.gov (United States)

Roy, Amit Saha; Saha, Pinaki; Adhikary, Nirmal Das; Ghosh, Prasanta

2011-03-21

The diamagnetic VO(2+)-iminobenzosemiquinonate anion radical (L(R)(IS)(•-), R = H, Me) complexes, (L(-))(VO(2+))(L(R)(IS)(•-)): (L(1)(-))(VO(2+))(L(H)(IS)(•-))•3/2MeOH (1•3/2MeOH), (L(2)(-))(VO(2+))(L(H)(IS)(•-)) (2), and (L(2)(-))(VO(2+))(L(Me)(IS)(•-))•1/2 L(Me)(AP) (3•1/2 L(Me)(AP)), incorporating tridentate monoanionic NNO-donor ligands {L = L(1)(-) or L(2)(-), L(1)H = (2-[(phenylpyridin-2-yl-methylene)amino]phenol; L(2)H = 1-(2-pyridylazo)-2-naphthol; L(H)(IS)(•-) = o-iminobenzosemiquinonate anion radical; L(Me)(IS)(•-) = o-imino-p-methylbenzosemiquinonate anion radical; and L(Me)(AP) = o-amino-p-methylphenol} have been isolated and characterized by elemental analyses, IR, mass, NMR, and UV-vis spectra, including the single-crystal X-ray structure determinations of 1•3/2MeOH and 3•1/2 L(Me)(AP). Complexes 1•3/2MeOH, 2, and 3•1/2 L(Me)(AP) absorb strongly in the visible region because of intraligand (IL) and ligand-to-metal charge transfers (LMCT). 1•3/2MeOH is luminescent (λ(ext), 333 nm; λ(em), 522, 553 nm) in frozen dichloromethane-toluene glass at 77 K due to π(diimine→)π(diimine)* transition. The V-O(phenolato) (cis to the V═O) lengths, 1.940(2) and 1.984(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP) are consistent with the VO(2+) description. The V-O(iminosemiquinonate) (trans to the V═O) lengths, 2.1324(19) in 1•3/2MeOH and 2.083(2) Å in 3•1/2 L(Me)(AP), are expectedly ∼0.20 Å longer due to the trans influence of the V═O bond. Because of the stronger affinity of the paramagnetic VO(2+) ion to the L(H)(IS)(•-) or L(Me)(IS)(•-), the V-N(iminosemiquinonate) lengths, 1.908(2) and 1.921(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP), are unexpectedly shorter. Density functional theory (DFT) calculations using B3LYP, B3PW91, and PBE1PBE functionals on 1 and 2 have established that the closed shell singlet (CSS) solutions (VO(3+)-amidophenolato (L(R)(AP)(2-)) coordination) of these

Superoxide anions and hydrogen peroxide induce hepatocyte death by different mechanisms : Involvement of JNK and ERK MAP kinases

NARCIS (Netherlands)

Conde de la Rosa, L; Schoemaker, MH; Vrenken, TE; Buist-Homan, M; Havinga, R; Jansen, PLM; Moshage, H

Background/Aims: In liver diseases, reactive oxygen species (ROS) are involved in cell death and liver injury, but the mechanisms are not completely elucidated. To elucidate the mechanisms of hepatocyte cell death induced by the ROS superoxide anions and hydrogen peroxide, primary cultures of

Superoxide anions and hydrogen peroxide induce hepatocyte death by different mechanisms: involvement of JNK and ERK MAP kinases

NARCIS (Netherlands)

Conde de la Rosa, Laura; Schoemaker, Marieke H.; Vrenken, Titia E.; Buist-Homan, Manon; Havinga, Rick; Jansen, Peter L. M.; Moshage, Han

2006-01-01

BACKGROUND/AIMS: In liver diseases, reactive oxygen species (ROS) are involved in cell death and liver injury, but the mechanisms are not completely elucidated. To elucidate the mechanisms of hepatocyte cell death induced by the ROS superoxide anions and hydrogen peroxide, primary cultures of

Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

OpenAIRE

Suvankar Das; Cristiane J. da Silva; Marina de M. Silva; Maria Dayanne de A. Dantas; Ângelo de Fátima; Ana Lúcia T. Góis Ruiz; Cleiton M. da Silva; João Ernesto de Carvalho; Josué C.C. Santos; Isis M. Figueiredo; Edeildo F. da Silva-Júnior; Thiago M. de Aquino; João X. de Araújo-Júnior; Goutam Brahmachari; Luzia Valentina Modolo

2018-01-01

Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the anion radical superoxide (·O2−). The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine...

First observation of alkyne radical anions by electron spin resonance spectroscopy: Hexyne/n-hexane mixed crystals

International Nuclear Information System (INIS)

Matsuura, K.; Muto, H.

1991-01-01

The radical anions of alkynes have been first observed by electron spin resonance spectroscopy following alkene anions previously studied. Hexyne radical anions were formed in 1-, 2-, or 3-hexyne/n--hexane mixed crystals irradiated at 4.2 or 77 K. The characters of the anions were as follows; (a) the α-proton hyperfine coupling is very large (∼4.5 mT for the 1-hexyne anion), (b) the β-proton couplings are very small (∼1.0 mT for C--H β proton with the conformational angle of 0 degree), and (c) the radicals show a negative g shift (2.0014). From these observations, it was found that the anions have a nonlinear(bent) molecule structure in the anticonfiguration (trans C--C≡C--C) with the bend angle ∼60 degree, and that the unpaired electron orbital is approximately composed of the anticombination of the sp 2 hybrid orbitals of the C≡C carbon atoms. A discussion based on complete neglect of differential overlap (CNDO) molecular orbital (MO) calculations was given for the observed negative g shift, which was shown to be characteristic of the alkyne anions which have a high-lying unpaired electron orbital and an antibonding 2p--2p π carbon orbital just above it on the upper energy side

Multiple free-radical scavenging (MULTIS) capacity in cattle serum.

Science.gov (United States)

Sueishi, Yoshimi; Kamogawa, Erisa; Kimura, Anna; Kitahara, Go; Satoh, Hiroyuki; Asanuma, Taketoshi; Oowada, Shigeru

2017-01-01

Multiple free-radical scavenging (MULTIS) activity in cattle and human sera was evaluated with electron spin resonance spectroscopy. Scavenging rates against six active species, namely hydroxyl radical, superoxide anion, alkoxyl radical, alkylperoxyl radical, methyl radical, and singlet oxygen were quantified. The difference in the electron spin resonance signal intensity in the presence and absence of the serum was converted into the scavenging rates. Comparative MULTIS measurements were made in sera from eight beef cattle, three fetal calves and fifteen healthy human volunteers. Further, we determined the MULTIS value of albumin, the most abundant component in serum. MULTIS values in cattle sera indicated higher scavenging activity against most free radical species tested than human sera. In particular, cattle serum scavenging activities against superoxide and methyl radical were higher than human serum by 2.6 and 3.7 fold, respectively. In cattle serum, albumin appears to play a dominant role in MULTIS activity, but in human serum that is not the case. Previous data indicated that the abundance of uric acid in bovine blood is nearly 80% less than humans; however, this difference does not explain the deviation in MULTIS profile.

Electrophoretic characterization of D. melanogaster strains deficient in endogenous anti-oxidants in combination with gamma radiation

International Nuclear Information System (INIS)

Gomar A, S.

2012-01-01

The free radicals derived of the oxygen and other reactive species are generated by endogenous processes as sub-products of the aerobic metabolism or by exogenous factors as the environmental pollution, the biological half life of these free radicals is of microseconds, but they have the capacity of reacting with any atom or molecule to its around causing oxidant stress and damage to molecules, cellular membranes and tissues. To counteract them, there is endogenous and exogenous anti-oxidants, the first ones are synthesized by the organism for maintaining the cellular homeostasis as the superoxide dismutase and catalase. There are recent evidences that indicate that the sodium cooper chlorophyllin (SCC) presents a dual effect reducing and/or increasing the induced genetic damage by different mutagenic agents. One hypothesis for this effect is that the SCC can act as oxidant per se or through some of their metabolites. Results more recent indicated that a similar of the SCC, the protoporphyrin-Ix, can produce genetic damage. In this work exogenous anti-oxidants were used, as the SCC, protoporphyrin-Ix or the bilirubin in the induction of endogenous anti-oxidants enzymes to evaluate the supposed oxidant activity of the SCC and/or their metabolites. Drosophila melanogaster strains deficient in superoxide dismutase, catalase and withered were used and a rustic strain Canton-S as control. In the three experiments were treated 60 males of 1 day of age, with SCC, protoporphyrin-Ix or bilirubin to one concentration of 69 m M during 12 days. Every 4 days 10 males were isolated to measure them the induction of superoxide dismutase and catalase. The results showed that the SCC, protoporphyrin-Ix and bilirubin considered like anti-oxidants, were able to increase the induction of the superoxide dismutase and catalase enzymes. This result maybe is because they are able to generate reactive species of oxygen, as the anion superoxide and the hydrogen peroxide. Among the three

Titanium dioxide induced cell damage: A proposed role of the carboxyl radical

Energy Technology Data Exchange (ETDEWEB)

Dodd, Nicholas J.F. [Ecotoxicology and Stress Biology Research Centre, School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Jha, Awadhesh N. [Ecotoxicology and Stress Biology Research Centre, School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)], E-mail: a.jha@plymouth.ac.uk

2009-01-15

Titanium dioxide (TiO{sub 2}) nanoparticles have been shown to be genotoxic to cells exposed to ultraviolet A (UVA) radiation. Using the technique of electron spin resonance (ESR) spin trapping, we have confirmed that the primary damaging species produced on irradiation of TiO{sub 2} nanoparticles is the hydroxyl (OH) radical. We have applied this technique to TiO{sub 2}-treated fish and mammalian cells under in vitro conditions and observed the additional formation of carboxyl radical anions (CO{sub 2}{sup -}) and superoxide radical anions (O{sub 2}{sup -}). This novel finding suggests a hitherto unreported pathway for damage, involving primary generation of OH radicals in the cytoplasm, which react to give CO{sub 2}{sup -} radicals. The latter may then react with cellular oxygen to form O{sub 2}{sup -} and genotoxic hydrogen peroxide (H{sub 2}O{sub 2})

Decay of peroxy radicals of methanol and isopropanol in the presence of copper ions and superoxide dismutase. Progress report, December 1, 1978--November 30, 1979

International Nuclear Information System (INIS)

Ilan, Y.A.; Ilan, Y.; Czapski, G.

1979-01-01

The decay of the peroxy radicals produced from methanol and isopropanol was followed in the presence and in the absence of Cu 2+ ions, and the enzyme Superoxide Dismutase. The results indicate that both Cu 2+ and Superoxide do not affect the decay of the alcohol peroxy radicals. They catalyze the decay of O - 2 radicals which are formed from the alcoholic peroxy radicals, and which absorb light at the same wavelengths region as these radicals. This catalysis enables the resolution of the decay of the alcoholic peroxy radicals, without the interference of absorption changes originating in the decay of HO 2 and O - 2 radicals

Analgesic, anti-inflammatory and antioxidant properties of Buddleja globosa, Buddlejaceae.

Science.gov (United States)

Backhouse, N; Rosales, L; Apablaza, C; Goïty, L; Erazo, S; Negrete, R; Theodoluz, C; Rodríguez, J; Delporte, C

2008-03-05

Buddleja globosa, known as "matico", is employed in Chile for wound healing. To validate the traditional use of the crude drug through in vivo and in vitro evaluation of the anti-inflammatory, analgesic and antioxidant properties of its extracts. Sequential hexane, dichloromethane, methanol and total methanol extracts were studied using bioguided fractionation. The following activities were investigated: analgesic (writhing test), oral and topic anti-inflammatory (paw- and ear-induced edema), free radical scavenging and antioxidant activities (1,1-diphenyl-2-picrylhydrazyl, DPPH, superoxide anion, lipid peroxidation and xanthine oxidase inhibition). Sodium naproxen, nimesulide, indomethacin were used as reference drugs for in vivo, quercetin and allopurinol for in vitro assays. A mixture of alpha- and beta-amyrins was isolated from the hexane extract that showed 41.2% of analgesic effect at 600 mg/kg, inhibited by 47.7 and 79.0% the arachidonic acid (AA) and 12-deoxyphorbol-13-decanoate (TPA)-induced inflammation at 3mg/20 microL/ear, respectively. A mixture of beta-sitosterol, stigmasterol, stigmastenol, stigmastanol and campesterol was isolated from the fraction CD4-N and beta-sitosterol-glycoside from the fraction CD5-N, reducing TPA-induced inflammation by 78.2 and 83.7% at 1mg/20 microL/ear, respectively. The fraction CD4-N at 300 mg/kg also showed analgesic activity (38.7%). The methanol extract at 600mg/kg per os showed anti-inflammatory effect (61.4%), topic anti-inflammatory (56.7% on TPA) and analgesic activity (38.5%). Verbascoside and luteolin-7-O-glucoside were the major components of the methanol extract; apigenin 7-O-glucoside was also detected. Inhibition of superoxide anion, lipoperoxidation, and DPPH bleaching effect was found in the methanol serial and global extracts. The present report demonstrate the analgesic and anti-inflammatory properties of Buddleja globosa and validate its use in Chilean traditional medicine.

Radiation-induced damage in E. coli B: The effect of superoxide radicals and molecular oxygen. Progress report, December 1, 1978--November 30, 1979

International Nuclear Information System (INIS)

Samuni, A.; Czapski, G.

The roles of superoxide radicals and of molecular oxygen in the radiodamage of E. coli B suspended in dilute phosphate buffer were studied. The presence of high concentrations of polyethylene glycol in the γ-irradiated cell suspensions, had no effect on bacterial radiosensitivity. This indicates that the damage was primarily endogenous, i.e. originated intracellularly. Saturation of the cell suspensions with N 2 O doubled the radiosensitivity, thus indicating that OH radicals are responsible for the majority of the damage (indirect radiation effect). The presence of oxygen either in the absence or presence of N 2 O brought about roughly a three-fold increase in the radiosensitivity. Since in the presence of N 2 O all e - /sub aq/ are scavenged by the nitrous oxide rather than by oxygen, this shows that superoxide radicals play no role in the bacterial radiodamage. Our results substantiate the attribution of the oxygen effect to a direct interaction of O 2 with the hydroxyl-radical-damaged sites on vital biomolecules, and exclude any significant contribution of e - /sub aq/ and superoxide radicals to the cellular radiodamage

Immobilization of Superoxide Dismutase on Polyelectrolyte-Functionalized Titania Nanosheets.

Science.gov (United States)

Rouster, Paul; Pavlovic, Marko; Szilagyi, Istvan

2018-02-16

The superoxide dismutase (SOD) enzyme was successfully immobilized on titania nanosheets (TNS) functionalized with the poly(diallyldimethylammonium chloride) (PDADMAC) polyelectrolyte. The TNS-PDADMAC solid support was prepared by hydrothermal synthesis followed by self-assembled polyelectrolyte layer formation. It was found that SOD strongly adsorbed onto oppositely charged TNS-PDADMAC through electrostatic and hydrophobic interactions. The TNS-PDADMAC-SOD material was characterized by light scattering and microscopy techniques. Colloidal stability studies revealed that the obtained nanocomposites possessed good resistance against salt-induced aggregation in aqueous suspensions. The enzyme kept its functional integrity upon immobilization; therefore, TNS-PDADMAC-SOD showed excellent superoxide radical anion scavenging activity. The developed system is a promising candidate for applications in which suspensions of antioxidant activity are required in the manufacturing processes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A superoxide anion-scavenger, 1,3-selenazolidin-4-one suppresses serum deprivation-induced apoptosis in PC12 cells by activating MAP kinase

International Nuclear Information System (INIS)

Nishina, Atsuyoshi; Kimura, Hirokazu; Kozawa, Kunihisa; Sommen, Geoffroy; Nakamura, Takao; Heimgartner, Heinz; Koketsu, Mamoru; Furukawa, Shoei

2011-01-01

Synthetic organic selenium compounds, such as ebselen, may show glutathione peroxidase-like antioxidant activity and have a neurotrophic effect. We synthesized 1,3-selenazolidin-4-ones, new types of synthetic organic selenium compounds (five-member ring compounds), to study their possible applications as antioxidants or neurotrophic-like molecules. Their superoxide radical scavenging effects were assessed using the quantitative, highly sensitive method of real-time kinetic chemiluminescence. At 166 μM, the O 2 − scavenging activity of 1,3-selenazolidin-4-ones ranged from 0 to 66.2%. 2-[3-(4-Methoxyphenyl)-4-oxo-1,3-selenazolidin-2-ylidene]malononitrile (compound b) showed the strongest superoxide anion-scavenging activity among the 6 kinds of 2-methylene-1,3-selenazolidin-4-ones examined. Compound b had a 50% inhibitory concentration (IC 50 ) at 92.4 μM and acted as an effective and potentially useful O 2 − scavenger in vitro. The effect of compound b on rat pheochromocytome cell line PC12 cells was compared with that of ebselen or nerve growth factor (NGF) by use of the MTT [3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay. When ebselen was added at 100 μM or more, toxicity toward PC12 cells was evident. On the contrary, compound b suppressed serum deprivation-induced apoptosis in PC12 cells more effectively at a concentration of 100 μM. The activity of compound b to phosphorylate mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) 1/2 (MAP kinase) in PC12 cells was higher than that of ebselen, and the former at 100 μM induced the phosphorylation of MAP kinase to a degree similar to that induced by NGF. From these results, we conclude that this superoxide anion-scavenger, compound b, suppressed serum deprivation-induced apoptosis by promoting the phosphorylation of MAP kinase. -- Highlights: ► We newly synthesized 1,3-selenazolidin-4-ones to study their possible applications. ► Among new

A superoxide anion-scavenger, 1,3-selenazolidin-4-one suppresses serum deprivation-induced apoptosis in PC12 cells by activating MAP kinase

Energy Technology Data Exchange (ETDEWEB)

Nishina, Atsuyoshi, E-mail: nishina@yone.ac.jp [Yonezawa Women' s Junior College, 6-15-1 Tohrimachi, Yonezawa, Yamagata 992-0025 (Japan); Kimura, Hirokazu; Kozawa, Kunihisa [Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamioki, Maebashi, Gunma 371-0052 (Japan); Sommen, Geoffroy [Lonza Braine SA, Chaussee de Tubize 297, B-1420 Braine l' Alleud (Belgium); Nakamura, Takao [Department of Biomedical Information Engineering, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585 (Japan); Heimgartner, Heinz [University of Zuerich, Institut of Organic Chemistry, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Koketsu, Mamoru [Department of Materials Science and Technology, Faculty of Engineering, Gifu University, Gifu 501-1193 (Japan); Furukawa, Shoei [Laboratory of Molecular Biology, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585 (Japan)

2011-12-15

Synthetic organic selenium compounds, such as ebselen, may show glutathione peroxidase-like antioxidant activity and have a neurotrophic effect. We synthesized 1,3-selenazolidin-4-ones, new types of synthetic organic selenium compounds (five-member ring compounds), to study their possible applications as antioxidants or neurotrophic-like molecules. Their superoxide radical scavenging effects were assessed using the quantitative, highly sensitive method of real-time kinetic chemiluminescence. At 166 {mu}M, the O{sub 2}{sup -} scavenging activity of 1,3-selenazolidin-4-ones ranged from 0 to 66.2%. 2-[3-(4-Methoxyphenyl)-4-oxo-1,3-selenazolidin-2-ylidene]malononitrile (compound b) showed the strongest superoxide anion-scavenging activity among the 6 kinds of 2-methylene-1,3-selenazolidin-4-ones examined. Compound b had a 50% inhibitory concentration (IC{sub 50}) at 92.4 {mu}M and acted as an effective and potentially useful O{sub 2}{sup -} scavenger in vitro. The effect of compound b on rat pheochromocytome cell line PC12 cells was compared with that of ebselen or nerve growth factor (NGF) by use of the MTT [3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay. When ebselen was added at 100 {mu}M or more, toxicity toward PC12 cells was evident. On the contrary, compound b suppressed serum deprivation-induced apoptosis in PC12 cells more effectively at a concentration of 100 {mu}M. The activity of compound b to phosphorylate mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) 1/2 (MAP kinase) in PC12 cells was higher than that of ebselen, and the former at 100 {mu}M induced the phosphorylation of MAP kinase to a degree similar to that induced by NGF. From these results, we conclude that this superoxide anion-scavenger, compound b, suppressed serum deprivation-induced apoptosis by promoting the phosphorylation of MAP kinase. -- Highlights: Black-Right-Pointing-Pointer We newly synthesized 1,3-selenazolidin-4-ones to

Study of organic radicals through anion photoelectron velocity-map imaging spectroscopy

Science.gov (United States)

Dixon, Andrew Robert

We report preliminary results on the photoelectron imaging of phenylcarbene, cyanophenylcarbene, and chlorophenylcarbene anions. Triplet phenylcarbene is observed to have an EA of ≤ 0.83 eV, considerably lower than the previously indirectly-determined value. Transitions to the singlet and triplet ground state of both cyanophenylcarbene and chlorophenylcarbene are observable, though unidentified bands make full assignment difficult. Cyanophenylcarbene is found to have a triplet ground-state, with a tentative EA of 2.04 eV. Chlorophenylcarbene is found to have a singlet ground-state. The phenyl-group is found to favor the singlet state slightly. The cyanofluoromethyl radical, FC(H)CN, was estimated to have an EA of 1.53 +/- 0.08 eV, by a combination of experimental and theoretical results.. With similar methodology, we report the adiabatic electron affinity of the cyanobenzyl radical, EA(PhCHCN) = 1.90 +/- 0.01 eV, and assign an upper limit of the EA for the chlorobenzyl radical, EA(PhCHCl) ≤ 1.12 eV. These values were used to estimate the C-H bond dissociation energy (BDE)s for these substituted methanes. Fluoroacetonitrile was found to have a BDE of D H198 = 90.7 +/- 2.8 kcal mol□1. The C-H bond dissociation energies at the benzyl-alpha sites of the phenylmethanes are determined as 80.9 +/- 2.3 kcal mol-1 for benzyl nitrile and an upper limit of 84.2 kcal mol-1 for benzyl chloride. These results are discussed in terms of substituent interactions in a simple MO framework and in relation to other similar molecules, including recently reported results for chloroacetonitrile. The 532 nm photoelectron spectrum of glyoxal provides the first direct spectroscopic determination of the adiabatic electron affinity, EA = 1.10(2) eV. This assignment is supported by a Franck-Condon simulation of the experimental spectrum that successfully reproduces the observed spectral features. The vertical detachment energy (VDE) of the glyoxal radical anion is determined as VDE = 1

Antioxidant activity of melatonin and glutathione interacting with hydroxyl- and superoxide anion radicals

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T. Y. Kuznetsova

2017-12-01

Full Text Available Based on the analysis of the results obtained by quantum chemical modeling of interaction between reduced glutathione (GSH and melatonin (MLT molecules with oxygen radicals (•OH and • OOˉ it was found that this interaction occured following the acid-base mechanism, where MLT and GSH acted as a base in respect of •OH, and as acid in respect of •OOˉ. We have carried out the correlation of the results of quantum chemical calculations (density redistribution, energetic characteristics under the interaction of MLT and GSH molecules with •OH and •OOˉ in changing macroscopic properties of the process of electroreduction of free oxygen radicals in the presence of antioxidants (potential and maximal current wave reduction waves. This was a direct experimental macroscale evidence of the results of theoretical modeling at the nanoscale level that pointed to a marked antioxidant activity of glutathione compared with melatonin.

Kinetics and mechanism of superoxide radical reactions with some biologically important compounds in aqueous solutions. Pulse radiolysis

Science.gov (United States)

Revina, A. A.; Amiragova, M. I.; Volod'ko, V. V.; Vannikov, A. V.

Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm -3 sodium formate and 2 mmol dm -3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O ⨪2 decay was monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O ⨪2. A red shift of O ⨪2 absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2s was observed to accompany the superoxo-complex of CoTSPc decay. In the aerated solution of HP the intensity of absorbance at 260 nm was found to be independent of the presence of formate ions.

Kinetics and mechanism of superoxide radical reactions with some biologically important compounds in aqueous solutions. Pulse radiolysis

International Nuclear Information System (INIS)

Revina, A.A.; Volod'ko, V.V.; Vannikov, A.V.

1989-01-01

Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm -3 sodium formate and 2 mmol dm -3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O 2 .-bar decay as monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O 2 .-bar . A red shift of 0 2 .-bar absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2 s was observed to accompany the superoxo-complex of CoTSPc decay. In the aerated solution of HP the intensity of absorbance at 260 nm was found to be independent of the presence of formate ions. (author)

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

Synergism between arsenite and proteasome inhibitor MG132 over cell death in myeloid leukaemic cells U937 and the induction of low levels of intracellular superoxide anion

International Nuclear Information System (INIS)

Lombardo, Tomás; Cavaliere, Victoria; Costantino, Susana N.; Kornblihtt, Laura; Alvarez, Elida M.; Blanco, Guillermo A.

2012-01-01

Increased oxygen species production has often been cited as a mechanism determining synergism on cell death and growth inhibition effects of arsenic-combined drugs. However the net effect of drug combination may not be easily anticipated solely from available knowledge of drug-induced death mechanisms. We evaluated the combined effect of sodium arsenite with the proteasome inhibitor MG132, and the anti-leukaemic agent CAPE, on growth-inhibition and cell death effect in acute myeloid leukaemic cells U937 and Burkitt's lymphoma-derived Raji cells, by the Chou–Talalay method. In addition we explored the association of cytotoxic effect of drugs with changes in intracellular superoxide anion (O 2 − ) levels. Our results showed that combined arsenite + MG132 produced low levels of O 2 − at 6 h and 24 h after exposure and were synergic on cell death induction in U937 cells over the whole dose range, although the combination was antagonistic on growth inhibition effect. Exposure to a constant non-cytotoxic dose of 80 μM hydrogen peroxide together with arsenite + MG132 changed synergism on cell death to antagonism at all effect levels while increasing O 2 − levels. Arsenite + hydrogen peroxide also resulted in antagonism with increased O 2 − levels in U937 cells. In Raji cells, arsenite + MG132 also produced low levels of O 2 − at 6 h and 24 h but resulted in antagonism on cell death and growth inhibition. By contrast, the combination arsenite + CAPE showed high levels of O 2 − production at 6 h and 24 h post exposure but resulted in antagonism over cell death and growth inhibition effects in U937 and Raji cells. We conclude that synergism between arsenite and MG132 in U937 cells is negatively associated to O 2 − levels at early time points after exposure. -- Highlights: ► Arsenic combined cytotoxic and anti-proliferative effects by Chou–Talalay method. ► Cytotoxic effect associated with superoxide levels as assessed by flow cytometry. ► Synergism

Fast reactions of organic anion radicals with organic halides in hexamethylphosphoric triamide studied by pulse radiolysis

International Nuclear Information System (INIS)

Honda, Eiji; Tokuda, Masao; Yoshida, Hiroshi; Ogasawara, Masaaki

1987-01-01

Fast reactions of diethyl fumarate anion radical (DEF - ) and fluorenone anion radical (Fl - ) with various organic halides (RX) in hexamethylphosphoric triamide have been studied by means of ns pulse radiolysis at room temperature. Reactions of acetophenone anion radical were also studied for comparison. It was found that the reaction rate of Fl - was subject to the steric and resonance effects of R groups of RX in accord with the classical concept of S N 2 reactions: the rate constant was reduced by 2 orders of magnitude by the steric effect when R was changed from ethyl to bulky isopropyl or t-butyl, and it was still large by the resonance effect of R even if R was changed from ethyl to an allyl or a benzyl group. While the reaction rate of DEF - was not much affected when R was changed to more bulky groups, the rate constant was correlated to the reduction potential of RX. The results were interpreted in terms of a VB correlation diagram approach or rate-equilibrium relationship within a framework of S N 2 reactions. (author)

Oxidation of alpha-tocopherol in micelles and liposomes by the hydroxyl, perhydroxyl, and superoxide free radicals

International Nuclear Information System (INIS)

Fukuzawa, K.; Gebicki, J.M.

1983-01-01

Rates of oxidation of alpha-tocopherol by the hydroxyl- and superoxide free radicals were measured. The radicals were produced in known yields by radiolysis of aqueous solutions with gamma rays. Two main systems were used to dissolve the tocopherol; micelles, made up from charged and uncharged amphiphiles, and membranes made from dimyristyl phosphatidylcholine which could be charged by addition of stearyl amine or dicetyl phosphate. The HO. radicals were efficient oxidants of alpha-tocopherol in all systems, with up to 83% of radicals generated in micelle and 32% in membrane suspensions initiating the oxidation. The HO 2 radical was an even more effective oxidant, but when most of it was in the O 2 form at neutral or alkaline pH, the oxidation rates became low. Tocopherol held in positively charged micelles or membranes was oxidized at a higher rate by the O 2 than in uncharged or negative particles. Possible biological significance of these results is discussed

Comparative study of copper(II)-curcumin complexes as superoxide dismutase mimics and free radical scavengers.

Science.gov (United States)

Barik, Atanu; Mishra, Beena; Kunwar, Amit; Kadam, Ramakant M; Shen, Liang; Dutta, Sabari; Padhye, Subhash; Satpati, Ashis K; Zhang, Hong-Yu; Indira Priyadarsini, K

2007-04-01

Two stoichiometrically different copper(II) complexes of curcumin (stoichiometry, 1:1 and 1:2 for copper:curcumin), were examined for their superoxide dismutase (SOD) activity, free radical-scavenging ability and antioxidant potential. Both the complexes are soluble in lipids and DMSO. The formation constants of the complexes were determined by voltammetry. EPR spectra of the complexes in DMSO at 77K showed that the 1:2 Cu(II)-curcumin complex is square planar and the 1:1 Cu(II)-curcumin complex is distorted orthorhombic. Cu(II)-curcumin complex (1:1) with larger distortion from square planar structure shows higher SOD activity. These complexes inhibit gamma-radiation induced lipid peroxidation in liposomes and react with DPPH acting as free radical scavengers. One-electron oxidation of the two complexes by radiolytically generated azide radicals in Tx-100 micellar solutions produced phenoxyl radicals, indicating that the phenolic moiety of curcumin in the complexes participates in free radical reactions. Depending on the structure, these two complexes possess different SOD activities, free radical neutralizing abilities and antioxidant potentials. In addition, quantum chemical calculations with density functional theory have been performed to support the experimental observations.

Free radicals in an adamantane matrix. XIII. Electron paramagnetic resonance study of sigma* - π* orbital crossover in fluorinated pyridine anions

International Nuclear Information System (INIS)

Yim, M.B.; DiGregorio, S.; Wood, D.E.

1977-01-01

Pentafluoropyridine,2,3,4,6-tetrafluoropyridine, 2,6-difluoropyridine, and 2-fluoropyridine anion radicals were produced by x irradiation of an adamantane matrix which was doubly doped with the aromatic precursors and Me 3 NBH 3 and their EPR spectra obtained. The large fluorine hyperfine splitting constants (hfsc) of penta- and 2,3,4,6-tetrafluoropyridine anions and the small fluorine hfsc's of 2,6-di- and 2-fluoropyridine anions suggest that the former two are sigma radicals while the latter two are π radicals. The sigma*-π* orbital crossover phenomenon observed in these fluorinated pyridine anions is explained in terms of the combined effects of stabilization of sigma* orbitals and destabilization of π* orbitals. The EPR results show that nitrogen has a negligible contribution to the unpaired electron sigma* orbitals. INDO calculations were performed for the various states and the results compared with experiment

(Ph4P)S6—A Compound Containing the Cyclic Radical Anion S6.−

NARCIS (Netherlands)

Neumuller, F.; Schmock, R.; Kirmse, A.; Voigt, A.; Diefenbach, A.; Bickelhaupt, F.M.; Dehnicke, K.

2000-01-01

Two long S−S bonds link the two S3 fragments in the cyclic radical anion S6.−. This forms as orange‐red crystals with PPh4+ as the counterion in the reaction of sulfane with (tetraphenylphosphonium) hydrogen diazide. The anion has a chair conformation with C2h symmetry (see picture).

Changes in free-radical scavenging ability of kombucha tea during fermentation.

Science.gov (United States)

Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

2008-07-01

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

The anti-oxidant effects of melatonin derivatives on human gingival fibroblasts.

Science.gov (United States)

Phiphatwatcharaded, Chawapon; Puthongking, Ploenthip; Chaiyarit, Ponlatham; Johns, Nutjaree Pratheepawanit; Sakolchai, Sumon; Mahakunakorn, Pramote

2017-07-01

Aim of this in vitro study was to evaluate the anti-oxidant activity of indole ring modified melatonin derivatives as compared with melatonin in primary human gingival fibroblast (HGF) cells. Anti-oxidant activity of melatonin (MLT), acetyl-melatonin (AMLT) and benzoyl-melatonin (BMLT) was evaluated by5 standard methods as follows: 2, 2-diphenyl-1-picrylhydrazyl (DPPH); ferric ion reducing antioxidant power (FRAP); superoxide anion scavenging; nitric oxide (NO) scavenging; and thiobarbituric acid reactive substances (TBARs).Evaluation of cellular antioxidant activity (CAA) and protectivity against H 2 O 2 induced cellular damage was performed via MTT assay in HGF cells. According to the standard anti-oxidant assays, the antioxidant power of AMLT and BMLT were slightly less than MLT in FRAP and superoxide scavenging assays. In the NO scavenging and TBARs assays, BMLT and AMLT were more potent than MLT, whereas DPPH assays demonstrated that MLT was more potent than others. BMLT and AMLT had more potent anti-oxidant and protective activities against H 2 O 2 in HGF cells as compared with MLT. MLT derivatives demonstrated different anti-oxidant activities as compared with MLT, depending upon assays. These findings imply that N-indole substitution of MLT may help to improve hydrogen atom transfer to free radicals but electron transfer property is slightly decreased. Anti-oxidant and protective effects of melatonin derivatives (AMLT and BMLT) on human gingival fibroblasts imply the potential use of these molecules as alternative therapeutics for chronic inflammatory oral diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Free radical inactivation of trypsin

International Nuclear Information System (INIS)

Cudina, Ivana; Jovanovic, S.V.

1988-01-01

Reactivities of free radical oxidants, radical OH, Br2-anion radical and Cl 3 COO radical and a reductant, CO2-anion radical, with trypsin and reactive protein components were determined by pulse radiolysis of aqueous solutions at pH 7, 20 0 C. Highly reactive free radicals, radical OH, Br2-anion radical and CO2-anion radical, react with trypsin at diffusion controlled rates. Moderately reactive trichloroperoxy radical, k(Cl 3 COO radical + trypsin) preferentially oxidizes histidine residues. The efficiency of inactivation of trypsin by free radicals is inversely proportional to their reactivity. The yields of inactivation of trypsin by radical OH, Br2-anion radical and CO2-anion radical are low, G(inactivation) = 0.6-0.8, which corresponds to ∼ 10% of the initially produced radicals. In contrast, Cl 3 COO radical inactivates trypsin with ∼ 50% efficiency, i.e. G(inactivation) = 3.2. (author)

Acute Superoxide Radical Scavenging Reduces Blood Pressure but Does Not Influence Kidney Function in Hypertensive Rats with Postischemic Kidney Injury

Directory of Open Access Journals (Sweden)

Zoran Miloradović

2014-01-01

Full Text Available Acute kidney injury (AKI is associated with significant morbidity and mortality in hypertensive surroundings. We investigated superoxide radical molecules influence on systemic haemodynamic and kidney function in spontaneously hypertensive rats (SHR with induced postischemic AKI. Experiment was performed in anesthetized adult male SHR. The right kidney was removed, and left renal artery was subjected to ischemia by clamping for 40 minutes. The treated group received synthetic superoxide dismutase mimetic TEMPOL in the femoral vein 5 minutes before, during, and 175 minutes after the period of reperfusion, while the control AKI group received the vehicle via the same route. All parameters were measured 24 h after renal reperfusion. TEMPOL treatment significantly decreased mean arterial pressure and total peripheral resistance P<0.05 compared to AKI control. It also increased cardiac output and catalase activity P<0.05. Lipid peroxidation and renal vascular resistance were decreased in TEMPOL P<0.05. Plasma creatinine and kidney morphological parameters were unchanged among TEMPOL treated and control groups. Our study shows that superoxide radicals participate in haemodynamic control, but acute superoxide scavenging is ineffective in glomerular and tubular improvement, probably due to hypertension-induced strong endothelial dysfunction which neutralizes beneficial effects of O2− scavenging.

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.

The role of anions on the indoor air quality; De rol van negatieve ionen op de binnenluchtkwaliteit

Energy Technology Data Exchange (ETDEWEB)

Havermans, J. [Afdeling Energie, Comfort en Binnenmilieu, TNO Bouw en Onderzoek, Delft (Netherlands)

2010-11-15

Anions may contribute to a more comfortable indoor environment. Even a simple apparatus as a lamp with semi conductor technique produces easily anions. Such ions will react with particles forming agglomerates that will precipitate. Also a reaction with oxygen and moist will result in the formation of a superoxide radical and peroxides. These radicals easily react with e.g. organic volatiles and possible also with spores and allergens. Depending on the concentration of the radicals, these compounds can be deteriorated fully. However, as a potential negative side effect the radicals can produce irritating substances by reaction with chemicals in the air. It is not clear yet if all cleaners, based on ionization, will cause this effect. Therefore more research is needed. [Dutch] Negatieve ionen (anionen) in de lucht kunnen een belangrijke bijdrage leveren aan een comfortabeler binnenmilieu en kunnen op een eenvoudige wijze worden geproduceerd. Bijvoorbeeld met lamp waarbij naast verlichting ook via (smd) halfgeleidertechniek negatieve ionen worden gevormd. Negatieve ionen reageren met deeltjes waardoor deze clusteren en deze uit de binnenlucht worden verwijderd. Ook kunnen ze met zuurstof en vocht reageren, waarbij reactief superoxide en peroxides worden gevormd. Deze radicalen zijn verantwoordelijk voor het verwijderen van bijvoorbeeld ongewenste geuren en mogelijk ook allergenen en schimmels. Ze kunnen ook als negatief bijeffect potentieel irriterende stoffen vormen door reactie met chemicalien in de lucht. Of dit het geval is met alle op ionisatie gebaseerde luchtzuiveringsapparaten dient nader te worden onderzocht.

Different activities of Schinus areira L.: anti-inflammatory or pro-inflammatory effect.

Science.gov (United States)

Davicino, R; Mattar, A; Casali, Y; Anesini, C; Micalizzi, B

2010-12-01

The anti-inflammatory drugs possess many serious side effects at doses commonly prescribed. It is really important to discover novel regulators of inflammation from natural sources with minimal adverse effects. Schinus areira L. is a plant native from South America and is used in folk medicine as an anti-inflammatory herb. For this study, the activity of aqueous extracts on inflammation and the effect on superoxide anion production in mice macrophages were assayed. Aqueous extracts were prepared by soaking herbs in cold water (cold extract), boiling water (infusion), and simmering water (decoction). Cold extract possess an anti-inflammatory activity. Decoction and infusion showed pro-inflammatory activity. Cold extract increased the production of superoxide anion. It has been proposed to use diverse methods to obtain extracts of S. areira L. with different effects. Cold extract, decoction, and infusion could be utilized as extracts or as pharmacological preparations for topical application.

Glutathione as a radical scavenger and the biological consequences of thiyl radical production

International Nuclear Information System (INIS)

Winterbourn, C.C.

1996-01-01

A large number of compounds that have toxic effects can be metabolised to free radicals and secondary reactive oxygen species. These may be directly damaging or affect cell function by altering regulatory mechanisms through changing redox status. Protection is provided by an integrated system of antioxidant defenses. This includes reduced glutathione (GSH), one of the functions of which is as a free radical scavenger. For GSH to be an effective radical scavenging antioxidant, therefore, it must act in concert with superoxide dismutase to remove the superoxide so generated. Superoxide is produced in a variety of metabolic processes. It is also a secondary product of radicals reacting with oxygen either directly or through GSH. The biological reactivity of superoxide has been the subject of much debate ever since the discovery of superoxide dismutase in 1968. It has more recently become apparent that its rapid reaction with nitric oxide to give peroxynitrite, and its ability to reversibly oxidise and inactivate iron sulphur enzymes, contribute to the toxicity of superoxide. Another mechanism that could be important involves addition reactions of superoxide with other radicals to give organic peroxides. This reaction, to form a tyrosine peroxide, has come to authors attention through the study of the scavenging of tyrosyl radicals by GSH. It is also shown that a tyrosine peroxide is a major product of the oxidation of tyrosine by neutrophils

Synergism between arsenite and proteasome inhibitor MG132 over cell death in myeloid leukaemic cells U937 and the induction of low levels of intracellular superoxide anion

Energy Technology Data Exchange (ETDEWEB)

Lombardo, Tomás [Laboratorio de Immunotoxicologia (LaITO), IDEHU-CONICET, Hospital de Clínicas, José de San Martín, Universidad de Buenos Aires (UBA), Buenos Aires (Argentina); Cavaliere, Victoria; Costantino, Susana N. [Laboratorio de Inmunología Tumoral (LIT), IDEHU-CONICET, Facultad de Farmacia y Bioquímica, UBA, Buenos Aires (Argentina); Kornblihtt, Laura [Servicio de Hematología, Hospital de Clínicas, José de San Martín (UBA), Buenos Aires (Argentina); Alvarez, Elida M. [Laboratorio de Inmunología Tumoral (LIT), IDEHU-CONICET, Facultad de Farmacia y Bioquímica, UBA, Buenos Aires (Argentina); Blanco, Guillermo A., E-mail: gblanco@ffyb.uba.ar [Laboratorio de Immunotoxicologia (LaITO), IDEHU-CONICET, Hospital de Clínicas, José de San Martín, Universidad de Buenos Aires (UBA), Buenos Aires (Argentina)

2012-02-01

Increased oxygen species production has often been cited as a mechanism determining synergism on cell death and growth inhibition effects of arsenic-combined drugs. However the net effect of drug combination may not be easily anticipated solely from available knowledge of drug-induced death mechanisms. We evaluated the combined effect of sodium arsenite with the proteasome inhibitor MG132, and the anti-leukaemic agent CAPE, on growth-inhibition and cell death effect in acute myeloid leukaemic cells U937 and Burkitt's lymphoma-derived Raji cells, by the Chou–Talalay method. In addition we explored the association of cytotoxic effect of drugs with changes in intracellular superoxide anion (O{sub 2}{sup −}) levels. Our results showed that combined arsenite + MG132 produced low levels of O{sub 2}{sup −} at 6 h and 24 h after exposure and were synergic on cell death induction in U937 cells over the whole dose range, although the combination was antagonistic on growth inhibition effect. Exposure to a constant non-cytotoxic dose of 80 μM hydrogen peroxide together with arsenite + MG132 changed synergism on cell death to antagonism at all effect levels while increasing O{sub 2}{sup −} levels. Arsenite + hydrogen peroxide also resulted in antagonism with increased O{sub 2}{sup −} levels in U937 cells. In Raji cells, arsenite + MG132 also produced low levels of O{sub 2}{sup −} at 6 h and 24 h but resulted in antagonism on cell death and growth inhibition. By contrast, the combination arsenite + CAPE showed high levels of O{sub 2}{sup −} production at 6 h and 24 h post exposure but resulted in antagonism over cell death and growth inhibition effects in U937 and Raji cells. We conclude that synergism between arsenite and MG132 in U937 cells is negatively associated to O{sub 2}{sup −} levels at early time points after exposure. -- Highlights: ► Arsenic combined cytotoxic and anti-proliferative effects by Chou–Talalay method. ► Cytotoxic effect

Physiology of free radicals

Directory of Open Access Journals (Sweden)

Stevanović Jelka

2011-01-01

Full Text Available Free radicals imply that every atom, molecule, ion, group of atoms, or molecules with one or several non-paired electrons in outer orbital. Among these are: nitrogenoxide (NO•, superoxide-anion-radical (O2•-, hydroxyl radical (OH•, peroxyl radical (ROO•, alcoxyl radical (RO• and hydroperoxyl radical (HO2•. However, reactive oxygen species also include components without non-paired electrons in outer orbital (so-called reactive non-radical agents, such as: singlet oxygen (1O2, peroxynitrite (ONOO-, hydrogen-peroxide (H2O2, hypochloric acid (eg. HOCl and ozone (O3. High concentrations of free radicals lead to the development of oxidative stress which is a precondition for numerous pathological effects. However, low and moderate concentrations of these matter, which occur quite normally during cell metabolic activity, play multiple significant roles in many reactions. Some of these are: regulation of signal pathways within the cell and between cells, the role of chemoattractors and leukocyte activators, the role in phagocytosis, participation in maintaining, changes in the position and shape of the cell, assisting the cell during adaption and recovery from damage (e.g.caused by physical effort, the role in normal cell growth, programmed cell death (apoptosis and cell ageing, in the synthesis of essential biological compounds and energy production, as well as the contribution to the regulation of the vascular tone, actually, tissue vascularization.

Assessment of phytochemicals, antioxidant, anti-lipid peroxidation and anti-hemolytic activity of extract and various fractions of Maytenus royleanus leaves.

Science.gov (United States)

Shabbir, Maria; Khan, Muhammad Rashid; Saeed, Naima

2013-06-22

Maytenus royleanus is traditionally used in gastro-intestinal disorders. The aim of this study was to evaluate the methanol extract of leaves and its derived fractions for various antioxidant assays and for its potential against lipid peroxidation and hemolytic activity. Various parameters including scavenging of free-radicals (DPPH, ABTS, hydroxyl and superoxide radical), hydrogen peroxide scavenging, Fe3+ to Fe2+ reducing capacity, total antioxidant capacity, anti-lipid peroxidation and anti-hemolytic activity were investigated. Methanol extract and its derived fractions were also subjected for chemical constituents. LC-MS was also performed on the methanol extract. Qualitative analysis of methanol extract exhibited the presence of alkaloids, anthraquinones, cardiac glycosides, coumarins, flavonoids, saponins, phlobatannins, tannins and terpenoids. LC-MS chromatogram indicated the composition of diverse compounds including flavonoids, phenolics and phytoestrogens. Methanol extract, its ethyl acetate and n-butanol fractions constituted the highest amount of total phenolic and flavonoid contents and showed a strong correlation coefficient with the IC50 values for the scavenging of DPPH, hydrogen peroxide radicals, superoxide radicals, anti-lipid peroxidation and anti-hemolytic efficacy. Moreover, n-butanol fraction showed the highest scavenging activity for ABTS radicals and for reduction of Fe3+ to Fe2+. Present results suggested the therapeutic potential of Maytenus royleanus leaves, in particular, methanol extract, ethyl acetate and n-butanol fraction as therapeutic agent against free-radical associated damages. The protective potential of the extract and or fraction may be attributed due to the high concentration of phenolic, flavonoid, tannins and terpenoids.

Mitochondria Superoxide Anion Production Contributes to Geranylgeraniol-Induced Death in Leishmania amazonensis

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Milene Valéria Lopes

2012-01-01

Full Text Available Here we demonstrate the activity of geranylgeraniol, the major bioactive constituent from seeds of Bixa orellana, against Leishmania amazonensis. Geranylgeraniol was identified through 1H and 13C nuclear magnetic resonance imaging and DEPT. The compound inhibited the promastigote and intracellular amastigote forms, with IC50 of 11±1.0 and 17.5±0.7 μg/mL, respectively. This compound was also more toxic to parasites than to macrophages and did not cause lysis in human blood cells. Morphological and ultrastructural changes induced by geranylgeraniol were observed in the protozoan by electronic microscopy and included mainly mitochondria alterations and an abnormal chromatin condensation in the nucleus. These alterations were confirmed by Rh 123 and TUNEL assays. Additionally, geranylgeraniol induces an increase in superoxide anion production. Collectively, our in vitro studies indicate geranylgeraniol as a selective antileishmanial that appears to be mediated by apoptosis-like cell death.

Antioxidant and Anti-Fatigue Activities of Flavonoids from Puerariae ...

African Journals Online (AJOL)

This study evaluated the antioxidant and anti-fatigue activities of flavonoids from Puerariae radix (FPR). In vitro antioxidant activities of FPR were investigated through hydroxyl and superoxide radical scavenging activities. In vivo anti-fatigue activity of FPR was investigated through loaded swimming exercise of mice. Results ...

Quantum chemical modeling of antioxidant activity of glutathione interacting with hydroxyl- and superoxide anion radicals

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N. V. Solovyova

2015-04-01

Full Text Available Following the analysis of the results of quantum chemical simulation of interaction between a GSH molecule and oxygen radicals •ОН and •ООˉ, it was found that it takes place through the acid-base mechanism, where GSH acts as a base towards •ОН, and as an acid towards •ООˉ. The results of quantum chemical calculations (electron density redistribution, energy characteristics were correlated at the time of interaction of a GSH molecule with •ОН and •ООˉ with a change of macroscopic parameters of the process of free oxygen radical electroreduction in the presence of GSH (potential and maximum current of reduction waves, which is a direct experimental macroscale evidence of results of the conducted nanoscale theoretical simulation.

Free radical scavenging and anti-oxidative activities of an ethanol-soluble pigment extract prepared from fermented Zijuan Pu-erh tea.

Science.gov (United States)

Fan, Jiang Ping; Fan, Chong; Dong, Wen Min; Gao, Bin; Yuan, Wei; Gong, Jia Shun

2013-09-01

An ethanol-soluble pigment extract was separated from fermented Zijuan Pu-erh tea. The compositions of the ethanol soluble pigment extract were analyzed by high-performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS). The extract was prepared into a series of ethanol solutions and analyzed for free radical-scavenging activities (against two free radicals: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)) and in vitro anti-oxidative properties. Electron spin resonance spectroscopy showed that the peaks of DPPH and TEMPO decreased with increasing extract concentration, suggesting that the extract had excellent free radical-scavenging activities. In vitro cell culture suggested that, at 50-200 mg/L, the extract had no measurable effect on the viability of vascular endothelial cells (ECV340) but produced significant protective effects for cells that underwent oxidative injuries due to hydrogen peroxide (H₂O₂) treatment. Compared with the H₂O₂ treatment alone cells group, 200 mg/L of the extract increased the activity of superoxide dismutase (SOD) in cells by 397.3%, and decreased the concentration of malondialdehyde (MDA) and the activity of lactate acid dehydrogenase (LDH) by 47.8% and 69.6%, respectively. These results suggest that the extract has excellent free radical scavenging and anti-oxidative properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Electrophoretic characterization of D. melanogaster strains deficient in endogenous anti-oxidants in combination with gamma radiation; Caracterizacion electroforetica de cepas de D. melanogaster deficientes en antioxidantes endogenos en combinacion con radiacion gamma

Energy Technology Data Exchange (ETDEWEB)

Gomar A, S.

2012-07-01

The free radicals derived of the oxygen and other reactive species are generated by endogenous processes as sub-products of the aerobic metabolism or by exogenous factors as the environmental pollution, the biological half life of these free radicals is of microseconds, but they have the capacity of reacting with any atom or molecule to its around causing oxidant stress and damage to molecules, cellular membranes and tissues. To counteract them, there is endogenous and exogenous anti-oxidants, the first ones are synthesized by the organism for maintaining the cellular homeostasis as the superoxide dismutase and catalase. There are recent evidences that indicate that the sodium cooper chlorophyllin (SCC) presents a dual effect reducing and/or increasing the induced genetic damage by different mutagenic agents. One hypothesis for this effect is that the SCC can act as oxidant per se or through some of their metabolites. Results more recent indicated that a similar of the SCC, the protoporphyrin-Ix, can produce genetic damage. In this work exogenous anti-oxidants were used, as the SCC, protoporphyrin-Ix or the bilirubin in the induction of endogenous anti-oxidants enzymes to evaluate the supposed oxidant activity of the SCC and/or their metabolites. Drosophila melanogaster strains deficient in superoxide dismutase, catalase and withered were used and a rustic strain Canton-S as control. In the three experiments were treated 60 males of 1 day of age, with SCC, protoporphyrin-Ix or bilirubin to one concentration of 69 m M during 12 days. Every 4 days 10 males were isolated to measure them the induction of superoxide dismutase and catalase. The results showed that the SCC, protoporphyrin-Ix and bilirubin considered like anti-oxidants, were able to increase the induction of the superoxide dismutase and catalase enzymes. This result maybe is because they are able to generate reactive species of oxygen, as the anion superoxide and the hydrogen peroxide. Among the three

Superoxide Anions and NO in the Paraventricular Nucleus Modulate the Cardiac Sympathetic Afferent Reflex in Obese Rats

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Qing-Bo Lu

2017-12-01

Full Text Available This study was conducted to explore the hypothesis that the endogenous superoxide anions (O2− and nitric oxide (NO system of the paraventricular nucleus (PVN regulates the cardiac sympathetic afferent reflex (CSAR contributing to sympathoexcitation in obese rats induced by a high-fat diet (42% kcal as fat for 12 weeks. CSAR was evaluated by monitoring the changes of renal sympathetic nerve activity (RSNA and the mean arterial pressure (MAP responses to the epicardial application of capsaicin (CAP in anaesthetized rats. In obese rats with hypertension (OH group or without hypertension (OB group, the levels of PVN O2−, angiotensinII (Ang II, Ang II type 1 receptor (AT1R, and nicotinamide adenine dinucleotide phosphate (NADPH oxidase were elevated, whereas neural NO synthase (nNOS and NO were significantly reduced. Moreover, CSAR was markedly enhanced, which promoted the elevation of plasma norepinephrine levels. The enhanced CSAR was attenuated by PVN application of the superoxide scavenger polyethylene glycol-superoxide dismutase (PEG-SOD and the NO donor sodium nitroprusside (SNP, and was strengthened by the superoxide dismutase inhibitor diethyldithiocarbamic acid (DETC and the nNOS inhibitor N(ω-propyl-l-arginine hydrochloride (PLA; conversely, there was a smaller CSAR response to PLA or SNP in rats that received a low-fat (12% kcal diet. Furthermore, PVN pretreatment with the AT1R antagonist losartan or with PEG-SOD, but not SNP, abolished Ang II-induced CSAR enhancement. These findings suggest that obesity alters the PVN O2− and NO system that modulates CSAR and promotes sympathoexcitation.

Resonance Raman Spectra of the Transient Cl2 and Br2 Radical Anions

DEFF Research Database (Denmark)

Wilbrandt, Robert Walter; Jensen, Niels-Henrik; Sillesen, Alfred Hegaard

1984-01-01

The resonance Raman spectra of the short-lived radical anions ClImage 2− and BrImage − in aqueous solution are reported. The observed wavenumbers of 279 cm−1 for ClImage − and 177 cm−1 for BrImage − are about 10% higher than those published for the corresponding species isolated in solid argon ma...

The role of mitochondrial superoxide anion (O2-) on physiological aging in C57BL/6J mice

International Nuclear Information System (INIS)

Miyazawa, Masaki; Ishii, Takamasa; Yasuda, Kayo; Onouchi, Hiromi; Ishii, Naoaki; Noda, Setsuko; Hartman, Philip S.

2009-01-01

Much attention has been focused on the mitochondrial superoxide anion (O 2 - ), which is also a critical free radical produced by ionizing radiation. The specific role of the mitochondrial O 2 - on physiological aging in mammals is still nuclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O 2 - is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O 2 - relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O 2 - production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O 2 - levels. Mitochondrial O 2 - production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O 2 - production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O 2 - production has high organ specificity, and oxidative damage by O 2 - from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O 2 - from mitochondria plays a core role in physiological aging. (author)

Effects of microsolvation on uracil and its radical anion: Uracil.(H2O)n (n=1-5)

Science.gov (United States)

Kim, Sunghwan; Schaefer, Henry F.

2006-10-01

Microsolvation effects on the stabilities of uracil and its anion have been investigated by explicitly considering the structures of complexes of uracil with up to five water molecules at the B3LYP /DZP++ level of theory. For all five systems, the global minimum of the neutral cluster has a different equilibrium geometry from that of the radical anion. Both the vertical detachment energy (VDE) and adiabatic electron affinity (AEA) of uracil are predicted to increase gradually with the number of hydrating molecules, qualitatively consistent with experimental results from a photodetachment-photoelectron spectroscopy study [J. Schiedt et al., Chem. Phys. 239, 511 (1998)]. The trend in the AEAs implies that while the conventional valence radical anion of uracil is only marginally bound in the gas phase, it will form a stable anion in aqueous solution. The gas-phase AEA of uracil (0.24eV) was higher than that of thymine by 0.04eV and this gap was not significantly affected by microsolvation. The largest AEA is that predicted for uracil•(H2O)5, namely, 0.96eV. The VDEs range from 0.76to1.78eV.

Surface modification of polystyrene with atomic oxygen radical anions-dissolved solution

International Nuclear Information System (INIS)

Wang Lian; Yan Lifeng; Zhao Peitao; Torimoto, Yoshifumi; Sadakata, Masayoshi; Li Quanxin

2008-01-01

A novel approach to surface modification of polystyrene (PS) polymer with atomic oxygen radical anions-dissolved solution (named as O - water) has been investigated. The O - water, generated by bubbling of the O - (atomic oxygen radical anion) flux into the deionized water, was characterized by UV-absorption spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. The O - water treatments caused an obvious increase of the surface hydrophilicity, surface energy, surface roughness and also caused an alteration of the surface chemical composition for PS surfaces, which were indicated by the variety of contact angle and material characterization by atomic force microscope (AFM) imaging, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and attenuated total-reflection Fourier transform infrared (ATR-FTIR) measurements. Particularly, it was found that some hydrophilic groups such as hydroxyl (OH) and carbonyl (C=O) groups were introduced onto the polystyrene surfaces via the O - water treatment, leading to the increases of surface hydrophilicity and surface energy. The active oxygen species would react with the aromatic ring molecules on the PS surfaces and decompose the aromatic compounds to produce hydrophilic hydroxyl and carbonyl compounds. In addition, the O - water is also considered as a 'clean solution' without adding any toxic chemicals and it is easy to be handled at room temperature. Present method may suit to the surface modification of polymers and other heat-sensitive materials potentially

Study of radicals, clusters and transition state species by anion photoelectron spectroscopy

International Nuclear Information System (INIS)

Arnold, D.W.

1994-08-01

Free radicals, elemental and van der Waals clusters and transition state species for bimolecular chemical reactions are investigated using anion photoelectron spectroscopy. Several low-lying electronic states of ozone have been identified via photoelectron spectroscopy of O 3 - . A characterization of these states is important to models for atmospheric ozone reaction kinetics. The fluoroformyloxyl radical, FCO 2 , has been investigated, providing vibrational frequencies and energies for two electronic states. The technique has also been employed to make the first direct observation and characterization of the NNO 2 molecule. Several electronic states are observed for this species which is believed to play a role as a reactive intermediate in the N + NO 2 reaction. The experimental results for all three of these radicals are supplemented by ab initio investigations of their molecular properties. The clusters investigations include studies of elemental carbon clusters (C 2 - - C 11 - ), and van der Waals clusters (X - (CO 2 ) n , X = I, Br, Cl; n ≤ 13 and I - (N 2 O) n=1--11 ). Primarily linear clusters are observed for the smaller carbon clusters, while the spectra of the larger clusters contain contribution from cyclic anion photodetachment. Very interesting ion-solvent interactions are observed in the X - (CO 2 )n clusters. The transition state regions for several bimolecular chemical reactions have also been investigated by photodetachment of a negative ion precursor possessing a geometry similar to that of the transition state species. These spectra show features which are assigned to motions of the unstable neutral complex existing between reactants and products

Purification, characterization and anti-aging capacity of mycelia zinc polysaccharide by Lentinus edodes SD-08.

Science.gov (United States)

Wang, Liqin; Wang, Cuiqin; Gao, Xia; Xu, Nuo; Lin, Lin; Zhao, Huajie; Jia, Shouhua; Jia, Le

2015-04-09

In the modern society, aging had been a major problem. People may rely on many medicines to delay it. However, lots of medicines were chemosynthetic, and they would do a bad side-effect on human body. Microbial sources could be used as a potential means of producing natural antioxidants. Lentinus edodes, commercial obtained in daily life, had recently become more attractive in physiological research. Zinc was now considered as a major element in assuring the correct functioning of an organism and essential for maintaining coordination of the major homeostatic networks. To investigate the bioconversion of zinc and the physiological effects of their complex (MZPS), the present studies were processed. Mycelia polysaccharides (MPS) and mycelia zinc polysaccharides (MZPS) of Lentinus edodes SD-08 were extracted by hot water leaching and purified by DEAE-52 cellulose anion-exchange column chromatography separately. The zinc content was determined by flame atomic absorption spectrometry. The evaluation of monosaccharide compositions and proportions used gas chromatogram. The analysis of molecular weight used HPGPC chromatogram. The typical structure of polysaccharide was evaluated by IR spectrum. The antioxidant activities in vitro measured through reducing power, the scavenging effects on hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The anti-aging activities in vivo measured through the total antioxidant capacity (T-AOC), GSH peroxide (GSH-Px), superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). MPS and MZPS of Lentinus edodes SD-08 were extracted and purified by DEAE-52 cellulose anion-exchange column chromatography separately, and four fractions (MPS-1, MPS-2, MZPS-1 and MZPS-2) were obtained. In addition, MPS composing of rhamnose, arabinose and mannose (molar proportion = 1.75:1.00:3.02) and MZPS containing rhamnose, arabinose, mannose and glucose (molar proportion = 7.19:2.26:1.00:8.39) were investigated by gas chromatography

Revisiting the electrochemical formation, stability and structure of radical and biradical anionic structures in dinitrobenzenes

International Nuclear Information System (INIS)

Hernandez-Munoz, Lindsay S.; Gonzalez, Felipe J.; Gonzalez, Ignacio; Goulart, Marilia O.F.; Abreu, Fabiane Caxico de; Ribeiro, Adriana Santos; Ribeiro, Rogerio Tavares; Longo, Ricardo L.; Navarro, Marcelo; Frontana, Carlos

2010-01-01

The effects of the position of a second nitroaromatic group (orthovs.paravs.meta) during reduction of nitrobenzenes were analysed. Cyclic voltammetric experiments in acetonitrile solution revealed that ortho-, meta- and para-dinitrobenzenes show two reversible reduction processes. An Electrochemical-Electron Spin Resonance (E-ESR) study showed that the corresponding radical anions of the ortho and para derivatives, electrogenerated during the first electron transfer uptake, remain the same even after the second monoelectronic process, increasing their intensity due to the presence of a comproportionation process (A 2- + A → 2A· - ). For the case of the meta derivative, the electrogenerated radical anion at the first reduction peak is consumed at the second reduction step, forming a secondary radical species. During the electrochemical study of methyl 3,5-dinitrobenzoate, two successive and reversible electron processes were also observed; however, in this case, a very rare biradical dianion structure was found. The use of ESR-spectroelectrochemistry shed some light on controversial aspects of nitroaromatic reduction, especially concerning the second and further waves. These results were corroborated and interpreted with quantum chemical calculations of the molecular and electronic structures, electron affinities and spin densities. As a result, electrochemical mechanisms are presented and discussed.

Senescence marker protein-30/superoxide dismutase 1 double knockout mice exhibit increased oxidative stress and hepatic steatosis

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Yoshitaka Kondo

2014-01-01

Full Text Available Superoxide dismutase 1 (SOD1 is an antioxidant enzyme that converts superoxide anion radicals into hydrogen peroxide and molecular oxygen. The senescence marker protein-30 (SMP30 is a gluconolactonase that functions as an antioxidant protein in mammals due to its involvement in ascorbic acid (AA biosynthesis. SMP30 also participates in Ca2+ efflux by activating the calmodulin-dependent Ca2+-pump. To reveal the role of oxidative stress in lipid metabolism defects occurring in non-alcoholic fatty liver disease pathogenesis, we generated SMP30/SOD1-double knockout (SMP30/SOD1-DKO mice and investigated their survival curves, plasma and hepatic lipid profiles, amounts of hepatic oxidative stress, and hepatic protein levels expressed by genes related to lipid metabolism. While SMP30/SOD1-DKO pups had no growth retardation by 14 days of age, they did have low plasma and hepatic AA levels. Thereafter, 39% and 53% of male and female pups died by 15–24 and 89 days of age, respectively. Compared to wild type, SMP30-KO and SOD1-KO mice, by 14 days SMP30/SOD1-DKO mice exhibited: (1 higher plasma levels of triglyceride and aspartate aminotransferase; (2 severe accumulation of hepatic triglyceride and total cholesterol; (3 higher levels of superoxide anion radicals and thiobarbituric acid reactive substances in livers; and (4 decreased mRNA and protein levels of Apolipoprotein B (ApoB in livers – ApoB is an essential component of VLDL secretion. These results suggest that high levels of oxidative stress due to concomitant deficiency of SMP30 and/or AA, and SOD1 cause abnormal plasma lipid metabolism, hepatic lipid accumulation and premature death resulting from impaired VLDL secretion.

Properties of the radicals formed by one-electron oxidation of acetaminophen - a pulse radiolysis study

International Nuclear Information System (INIS)

Bisby, R.H.; Tabassum, N.

1988-01-01

The semi-iminoquinone radical of acetaminophen, which has previously been proposed as a possible hepatotoxic intermediate in the cytochrome P-450 catalysed oxidation of acetaminophen, has been generated and studied by pulse radiolysis. In the absence of other reactive solutes, the radical decays rapidly by second order kinetics with a rate constant (2k 2 ) of (2.2 ± 0.4) x 10 9 M -1 sec -1 . In alkaline solutions the radical deprotonates with a pK of 11.1 ± 0.1 to form a radical-anion. The acetaminophen radical-anion reacts with resorcinol at high pH values, leading to the formation of a transient equilibrium from which the one-electron reduction potential of the semi-iminoquinone radical of acetaminophen is estimated to be + 0.707 ± 0.01 V at pH 7. This value predicts that acetaminophen should be oxidised by thiyl radicals. This was confirmed by pulse radiolysis experiments for reaction of the cysteinyl radical, for which rate constants of 7 x 10 6 M -1 sec -1 at pH7 and 2.7 x 10 8 M -1 sec -1 at pH 11.3 were obtained. The reaction of O 2 with the acetaminophen semi-iminoquinone radical could not be detected by pulse radiolysis, and alternative mechanisms for superoxide radical formation are discussed. (author)

Properties of the radicals formed by one-electron oxidation of acetaminophen - a pulse radiolysis study

Energy Technology Data Exchange (ETDEWEB)

Bisby, R H; Tabassum, N

1988-07-15

The semi-iminoquinone radical of acetaminophen, which has previously been proposed as a possible hepatotoxic intermediate in the cytochrome P-450 catalysed oxidation of acetaminophen, has been generated and studied by pulse radiolysis. In the absence of other reactive solutes, the radical decays rapidly by second order kinetics with a rate constant (2k/sub 2/) of (2.2 +- 0.4) x 10/sup 9/ M/sup -1/ sec/sup -1/. In alkaline solutions the radical deprotonates with a pK of 11.1 +- 0.1 to form a radical-anion. The acetaminophen radical-anion reacts with resorcinol at high pH values, leading to the formation of a transient equilibrium from which the one-electron reduction potential of the semi-iminoquinone radical of acetaminophen is estimated to be + 0.707 +- 0.01 V at pH 7. This value predicts that acetaminophen should be oxidised by thiyl radicals. This was confirmed by pulse radiolysis experiments for reaction of the cysteinyl radical, for which rate constants of 7 x 10/sup 6/ M/sup -1/ sec/sup -1/ at pH7 and 2.7 x 10/sup 8/ M/sup -1/ sec/sup -1/ at pH 11.3 were obtained. The reaction of O/sub 2/ with the acetaminophen semi-iminoquinone radical could not be detected by pulse radiolysis, and alternative mechanisms for superoxide radical formation are discussed.

New derivatives of 3,4-dihydroisoquinoline-3-carboxylic acid with free-radical scavenging, D-amino acid oxidase, acetylcholinesterase and butyrylcholinesterase inhibitory activity.

Science.gov (United States)

Solecka, Jolanta; Guśpiel, Adam; Postek, Magdalena; Ziemska, Joanna; Kawęcki, Robert; Lęczycka, Katarzyna; Osior, Agnieszka; Pietrzak, Bartłomiej; Pypowski, Krzysztof; Wyrzykowska, Agata

2014-09-30

A series of 3,4-dihydroisoquinoline-3-carboxylic acid derivatives were synthesised and tested for their free-radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+), superoxide anion radical (O2·-) and nitric oxide radical (·NO) assays. We also studied d-amino acid oxidase (DAAO), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity. Almost each of newly synthesised compounds exhibited radical scavenging capabilities. Moreover, several compounds showed moderate inhibitory activities against DAAO, AChE and BuChE. Compounds with significant free-radical scavenging activity may be potential candidates for therapeutics used in oxidative-stress-related diseases.

Colorless to purple-red switching electrochromic anthraquinone imides with broad visible/near-IR absorptions in the radical anion state: simulation-aided molecular design.

Science.gov (United States)

Chen, Fengkun; Zhang, Jie; Jiang, Hong; Wan, Xinhua

2013-07-01

The large redshift of near-infrared (NIR) absorptions of nitro-substituted anthraquinone imide (Nitro-AQI) radical anions, relative to other AQI derivatives, is rationalized based on quantum chemical calculations. Calculations reveal that the delocalization effects of electronegative substitution in the radical anion states is dramatically enhanced, thus leading to a significant decrease in the HOMO-LUMO band gap in the radical anion states. Based on this understanding, an AQI derivative with an even stronger electron-withdrawing dicyanovinyl (di-CN) substituent was designed and prepared. The resulting molecule, di-CN-AQI, displays no absorption in the Vis/NIR region in the neutral state, but absorbs intensively in the range of λ=700-1000 (λmax ≈860 nm) and λ=1100-1800 nm (λmax ≈1400 nm) upon one-electron reduction; this is accompanied by a transition from a highly transmissive colorless solution to one that is purple-red. The relationship between calculated radical anionic HOMO-LUMO gaps and the electron-withdrawing capacity of the substituents is also determined by employing Hammett parameter, which could serve as a theoretical tool for further molecular design. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design of a New Near-Infrared Ratiometric Fluorescent Nanoprobe for Real-Time Imaging of Superoxide Anions and Hydroxyl Radicals in Live Cells and in Situ Tracing of the Inflammation Process in Vivo.

Science.gov (United States)

Liu, Rongjun; Zhang, Liangliang; Chen, Yunyun; Huang, Zirong; Huang, Yong; Zhao, Shulin

2018-04-03

The superoxide anion (O 2 •- ) and hydroxyl radical ( • OH) are important reactive oxygen species (ROS) used as biomarkers in physiological and pathological processes. ROS generation is closely related to the development of a variety of inflammatory diseases. However, the changes of ROS are difficult to ascertain with in situ tracing of the inflammation process by real-time monitoring, owing to the short half-lives of ROS and high tissue autofluorescence in vivo. Here we developed a new near-infrared (NIR) ratiometric fluorescence imaging approach by using a Förster resonance energy transfer (FRET)-based ratiometric fluorescent nanoprobe for real-time monitoring of O 2 •- and • OH generation and also by using in situ tracing of the inflammation process in vivo. The proposed nanoprobe was composed of PEG functionalized GQDs as the energy donor connecting to hydroIR783, serving as both the O 2 •- / • OH recognizing ligand and the energy acceptor. The nanoprobe not only exhibited a fast response to O 2 •- and • OH but also presented good biocomapatibility as well as a high photostability and signal-to-noise ratio. We have demonstrated that the proposed NIR ratiometric fluorescent nanoprobe can monitor the changes of O 2 •- and • OH in living RAW 264.7 cells via a drug mediating inflammation model and further realized visual monitoring of the change of O 2 •- and • OH in mice for in situ tracing of the inflammation process. Our design may provide a new paradigm for long-term and real-time imaging applications for in vivo tracing of the pathological process related to the inflammatory diseases.

Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells

OpenAIRE

Bozic, Iva; Savic, Danijela; Stevanovic, Ivana; Pekovic, Sanja; Nedeljkovic, Nadezda; Lavrnja, Irena

2015-01-01

Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate) possesses anti-inflammat...

Determination of superoxide dismutase mimetic activity in common culinary herbs.

Science.gov (United States)

Chohan, Magali; Naughton, Declan P; Opara, Elizabeth I

2014-01-01

Under conditions of oxidative stress, the removal of superoxide, a free radical associated with chronic inflammation, is catalysed by superoxide dismutase (SOD). Thus in addition to acting as an antioxidant, SOD may also be utilized as an anti-inflammatory agent. Some plant derived foods have been shown to have SOD mimetic (SODm) activity however it is not known if this activity is possessed by culinary herbs which have previously been shown to possess both antioxidant and anti-inflammatory properties. The aim of the study was to ascertain if the culinary herbs rosemary, sage and thyme possess SODm activity, and to investigate the influence of cooking and digestion on this activity. Transition metal ion content was also determined to establish if it could likely contribute to any SODm activity detected. All extracts of uncooked (U), cooked (C) and cooked and digested (C&D) herbs were shown to possess SODm activity, which was significantly correlated with previously determined antioxidant and anti-inflammatory activities of these herbs. SODm activity was significantly increased following (C) and (C&D) for rosemary and sage only. The impact of (C) and (C&D) on the SODm for thyme may have been influenced by its transition metal ion content. SODm activity may contribute to the herbs' antioxidant and anti-inflammatory activities however the source and significance of this activity need to be established.

Determination of Antioxidant and Anti-Melanogenesis Activities of ...

African Journals Online (AJOL)

ethylbenzothiazoline-6-sulphonic acid) (ABTS, superoxide dismutase (SOD)-like activity, 2,2-diphenyl-1- picrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) while anti-melanogensis activity was evaluated by tyrosinase enzyme activity and B16 melanoma cell assays (melanin inhibition and cytotoxicity).

Revisiting the electrochemical formation, stability and structure of radical and biradical anionic structures in dinitrobenzenes

Energy Technology Data Exchange (ETDEWEB)

Hernandez-Munoz, Lindsay S.; Gonzalez, Felipe J. [Departamento de Quimica, Centro de Investigacion y Estudios Avanzados, Av. I.P.N. 2508. Col. San Pedro Zacatenco, 07360, D.F. (Mexico); Gonzalez, Ignacio [Departamento de Quimica, Universidad Autonoma Metropolitana-Iztapalapa, Area de Electroquimica, Apartado Postal 55-534, 09340, D.F. (Mexico); Goulart, Marilia O.F.; Abreu, Fabiane Caxico de; Ribeiro, Adriana Santos [Instituto de Quimica e Biotecnologia, Universidade Federal de Alagoas, Tabuleiro do Martins, Maceio, AL, 57072-970 (Brazil); Ribeiro, Rogerio Tavares; Longo, Ricardo L. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, s/n, Cid. Universitaria, Recife, PE, 50740-540 (Brazil); Navarro, Marcelo, E-mail: navarro@ufpe.b [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, s/n, Cid. Universitaria, Recife, PE, 50740-540 (Brazil); Frontana, Carlos, E-mail: ultrabuho@yahoo.com.m [Departamento de Quimica, Centro de Investigacion y Estudios Avanzados, Av. I.P.N. 2508. Col. San Pedro Zacatenco, 07360, D.F. (Mexico)

2010-11-30

The effects of the position of a second nitroaromatic group (orthovs.paravs.meta) during reduction of nitrobenzenes were analysed. Cyclic voltammetric experiments in acetonitrile solution revealed that ortho-, meta- and para-dinitrobenzenes show two reversible reduction processes. An Electrochemical-Electron Spin Resonance (E-ESR) study showed that the corresponding radical anions of the ortho and para derivatives, electrogenerated during the first electron transfer uptake, remain the same even after the second monoelectronic process, increasing their intensity due to the presence of a comproportionation process (A{sup 2-} + A {yields} 2A{center_dot}{sup -}). For the case of the meta derivative, the electrogenerated radical anion at the first reduction peak is consumed at the second reduction step, forming a secondary radical species. During the electrochemical study of methyl 3,5-dinitrobenzoate, two successive and reversible electron processes were also observed; however, in this case, a very rare biradical dianion structure was found. The use of ESR-spectroelectrochemistry shed some light on controversial aspects of nitroaromatic reduction, especially concerning the second and further waves. These results were corroborated and interpreted with quantum chemical calculations of the molecular and electronic structures, electron affinities and spin densities. As a result, electrochemical mechanisms are presented and discussed.

The Cu,Zn Superoxide Dismutase: not only a dismutase enzyme

Directory of Open Access Journals (Sweden)

Paolo Mondola

2016-11-01

Full Text Available The Cu,Zn superoxide dismutase (SOD1 is an ubiquitary cytosolic dimeric carbohydrate free molecule, belonging to a family of isoenzymes involved in the scavenger of superoxide anions. This effect certainly represents the main and well known function ascribed to this enzyme. Here we highlight new aspects of SOD1 physiology that point out some inedited effects of this enzyme in addition to the canonic role of oxygen radical enzymatic dismutation. In the last two decades our research group produced many data obtained in in vitro studies performed in many cellular lines, mainly neuroblastoma SK-N-BE cells, indicating that this enzyme is secreted either constitutively or after depolarization induced by high extracellular K+ concentration. In addition, we gave many experimental evidences showing that SOD1 is able to stimulate, through muscarinic M1 receptor, pathways involving ERK1/2 and AKT activation. These effects are accompanied with an intracellular calcium increase. In the last part of this review we describe researches that link deficient extracellular secretion of mutant SOD1G93A to its intracellular accumulation and toxicity in NSC-34 cells. Alternatively, SOD1G93A toxicity has been attributed to a decrease of Km for H2O2 with consequent OH. radical formation. Interestingly, this last inedited effect of SOD1G93A could represent a gain of function that could be involved in the pathogenesis of familial Amyotrophic Lateral Sclerosis (fALS.

Involvement of active oxygen in lipid peroxide radical reaction of epidermal homogenate following ultraviolet light exposure

International Nuclear Information System (INIS)

Nishi, J.; Ogura, R.; Sugiyama, M.; Hidaka, T.; Kohno, M.

1991-01-01

To elucidate the radical mechanism of lipid peroxidation induced by ultraviolet light (UV) irradiation, an electron spin resonance (ESR) study was made on epidermal homogenate prepared from albino rat skin. The exposure of the homogenate to UV light resulted in an increase in lipid peroxide content, which was proportional to the time of UV exposure. Using ESR spin trapping (dimethyl-1-pyrroline-N-oxide, DMPO), the DMPO spin adduct spectrum of lipid radicals (L.) was measured following UV exposure (DMPO-L.:aN = 15.5 G, aH = 22.7 G), as was the spectrum of DMPO-hydroxyl radical (DMPO-OH, aN = aH = 15.5 G). In the presence of superoxide dismutase, the DMPO spin adduct spectrum of lipid radicals was found to be reduced remarkably. Therefore, it was shown that the generation of the lipid radicals partially involves superoxide anion radicals, in addition to hydroxyl radicals. In the ESR free-radical experiment, an ESR signal appeared at g = 2.0064 when the ESR tube filled with homogenate was exposed to UV light at -150 degrees C. The temperature-dependent change in the ESR free radical signal of homogenate exposed to UV light was observed at temperatures varying from -150 degrees C to room temperature. By using degassed samples, it was confirmed that oxygen is involved in the formation of the lipid peroxide radicals (LOO.) from the lipid radicals (L.)

Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells

Directory of Open Access Journals (Sweden)

Iva eBozic

2015-09-01

Full Text Available Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate possesses anti-inflammatory effects. Here, the effects of benfotiamine on the pro-oxidative component of activity of LPS-stimulated BV-2 cells were investigated. The activation of microglia was accompanied by upregulation of intracellular antioxidative defense, which was further promoted in the presence of benfotiamine. Namely, activated microglia exposed to non-cytotoxic doses of benfotiamine showed increased levels and activities of hydrogen peroxide- and superoxide-removing enzymes – catalase and glutathione system, and superoxide dismutase. In addition, benfotiamine showed the capacity to directly scavenge superoxide radical anion. As a consequence, benfotiamine suppressed the activation of microglia and provoked a decrease in NO and •O2- production and lipid peroxidation. In conclusion, benfotiamine might silence pro-oxidative activity of microglia to alleviate/prevent oxidative damage of neighboring CNS cells.

Benfotiamine upregulates antioxidative system in activated BV-2 microglia cells.

Science.gov (United States)

Bozic, Iva; Savic, Danijela; Stevanovic, Ivana; Pekovic, Sanja; Nedeljkovic, Nadezda; Lavrnja, Irena

2015-01-01

Chronic microglial activation and resulting sustained neuroinflammatory reaction are generally associated with neurodegeneration. Activated microglia acquires proinflammatory cellular profile that generates oxidative burst. Their persistent activation exacerbates inflammation, which damages healthy neurons via cytotoxic mediators, such as superoxide radical anion and nitric oxide. In our recent study, we have shown that benfotiamine (S-benzoylthiamine O-monophosphate) possesses anti-inflammatory effects. Here, the effects of benfotiamine on the pro-oxidative component of activity of LPS-stimulated BV-2 cells were investigated. The activation of microglia was accompanied by upregulation of intracellular antioxidative defense, which was further promoted in the presence of benfotiamine. Namely, activated microglia exposed to non-cytotoxic doses of benfotiamine showed increased levels and activities of hydrogen peroxide- and superoxide-removing enzymes-catalase and glutathione system, and superoxide dismutase. In addition, benfotiamine showed the capacity to directly scavenge superoxide radical anion. As a consequence, benfotiamine suppressed the activation of microglia and provoked a decrease in NO and (·)O(-) 2 production and lipid peroxidation. In conclusion, benfotiamine might silence pro-oxidative activity of microglia to alleviate/prevent oxidative damage of neighboring CNS cells.

Superoxide activates mitochondrial uncoupling protein 2 from the matrix side. Studies using targeted antioxidants.

Science.gov (United States)

Echtay, Karim S; Murphy, Michael P; Smith, Robin A J; Talbot, Darren A; Brand, Martin D

2002-12-06

Superoxide activates nucleotide-sensitive mitochondrial proton transport through the uncoupling proteins UCP1, UCP2, and UCP3 (Echtay, K. S., et al. (2002) Nature 415, 1482-1486). Two possible mechanisms were proposed: direct activation of the UCP proton transport mechanism by superoxide or its products and a cycle of hydroperoxyl radical entry coupled to UCP-catalyzed superoxide anion export. Here we provide evidence for the first mechanism and show that superoxide activates UCP2 in rat kidney mitochondria from the matrix side of the mitochondrial inner membrane: (i) Exogenous superoxide inhibited matrix aconitase, showing that external superoxide entered the matrix. (ii) Superoxide-induced uncoupling was abolished by low concentrations of the mitochondrially targeted antioxidants 10-(6'-ubiquinonyl)decyltriphenylphosphonium (mitoQ) or 2-[2-(triphenylphosphonio)ethyl]-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol bromide (mitoVit E), which are ubiquinone (Q) or tocopherol derivatives targeted to the matrix by covalent attachment to triphenylphosphonium cation. However, superoxide-induced uncoupling was not affected by similar concentrations of the nontargeted antioxidants Q(o), Q(1), decylubiquinone, vitamin E, or 6-hydroxy-2,5,7,8-tetramethylchroman 2-carboxylic acid (TROLOX) or of the mitochondrially targeted but redox-inactive analogs decyltriphenylphosphonium or 4-chlorobutyltriphenylphosphonium. Thus matrix superoxide appears to be necessary for activation of UCP2 by exogenous superoxide. (iii) When the reduced to oxidized ratio of mitoQ accumulated by mitochondria was increased by inhibiting cytochrome oxidase, it induced nucleotide-sensitive uncoupling that was not inhibited by external superoxide dismutase. Under these conditions quinols are known to produce superoxide, and because mitoQ is localized within the mitochondrial matrix this suggests that production of superoxide in the matrix was sufficient to activate UCP2. Furthermore, the superoxide

A novel amperometric biosensor for superoxide anion based on superoxide dismutase immobilized on gold nanoparticle-chitosan-ionic liquid biocomposite film

International Nuclear Information System (INIS)

Wang Lu; Wen Wei; Xiong Huayu; Zhang Xiuhua; Gu Haoshuang; Wang Shengfu

2013-01-01

Graphical abstract: Schematic representation of the assembly process of SOD/GNPs-CS-IL/GCE. Highlights: ► SOD was immobilized in gold nanoparticles-chitosan-ionic liquid (GNPs-CS-IL) film. ► The biosensor was constructed by one-step ultrasonic electrodeposition of GNPs-CS-IL onto GCE. ► The biosensor showed excellent analytical performance for O 2 · − real-time analysis. - Abstract: A novel superoxide anion (O 2 · − ) biosensor is proposed based on the immobilization of copper-zinc superoxide dismutase (SOD) in a gold nanoparticle-chitosan-ionic liquid (GNPs-CS-IL) biocomposite film. The SOD-based biosensor was constructed by one-step ultrasonic electrodeposition of GNP-CS-IL composite onto glassy carbon electrode (GCE), followed by immobilization of SOD on the modified electrode. Surface morphologies of a set of representative films were characterized by scanning electron microscopy. The electrochemical performance of the biosensor was evaluated by cyclic voltammetry and chronoamperometry. A pair of quasi-reversible redox peaks of SOD with a formal potential of 0.257 V was observed at SOD/GNPs-CS-IL/GCE in phosphate buffer solution (PBS, 0.1 M, pH 7.0). The effects of varying test conditions on the electrochemical behavior of the biosensor were investigated. Furthermore, several electrochemical parameters were calculated in detail. Based on the biomolecule recognition of the specific reactivity of SOD toward O 2 · − , the developed biosensor exhibited a fast amperometric response ( 3 nM), low detection limit (1.7 nM), and excellent selectivity for the real-time measurement of O 2 · − . The proposed method is promising for estimating quantitatively the dynamic changes of O 2 · − in biological systems.

Importance of sulfate radical anion formation and chemistry in heterogeneous OH oxidation of sodium methyl sulfate, the smallest organosulfate

Science.gov (United States)

Chung Kwong, Kai; Chim, Man Mei; Davies, James F.; Wilson, Kevin R.; Nin Chan, Man

2018-02-01

Organosulfates are important organosulfur compounds present in atmospheric particles. While the abundance, composition, and formation mechanisms of organosulfates have been extensively investigated, it remains unclear how they transform and evolve throughout their atmospheric lifetime. To acquire a fundamental understanding of how organosulfates chemically transform in the atmosphere, this work investigates the heterogeneous OH radical-initiated oxidation of sodium methyl sulfate (CH3SO4Na) droplets, the smallest organosulfate detected in atmospheric particles, using an aerosol flow tube reactor at a high relative humidity (RH) of 85 %. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (direct analysis in real time, DART) coupled with a high-resolution mass spectrometer showed that neither functionalization nor fragmentation products are detected. Instead, the ion signal intensity of the bisulfate ion (HSO4-) has been found to increase significantly after OH oxidation. We postulate that sodium methyl sulfate tends to fragment into a formaldehyde (CH2O) and a sulfate radical anion (SO4 ṡ -) upon OH oxidation. The formaldehyde is likely partitioned back to the gas phase due to its high volatility. The sulfate radical anion, similar to OH radical, can abstract a hydrogen atom from neighboring sodium methyl sulfate to form the bisulfate ion, contributing to the secondary chemistry. Kinetic measurements show that the heterogeneous OH reaction rate constant, k, is (3.79 ± 0.19) × 10-13 cm3 molecule-1 s-1 with an effective OH uptake coefficient, γeff, of 0.17 ± 0.03. While about 40 % of sodium methyl sulfate is being oxidized at the maximum OH exposure (1.27 × 1012 molecule cm-3 s), only a 3 % decrease in particle diameter is observed. This can be attributed to a small fraction of particle mass lost via the formation and volatilization of formaldehyde. Overall, we firstly demonstrate that the heterogeneous OH oxidation of an

A study on the comparison of antioxidant effects among cultivated ginseng, and cultivated wild ginseng extracts -Using the measurement of superoxide and hydroxy radical scavenging activities-

Directory of Open Access Journals (Sweden)

Tae Jin, Rhim

2009-06-01

Full Text Available Objectives : The objective of this study was to compare the antioxidant effects among cultivated wild ginseng and ginseng extracts. Methods : In vitro antioxidant activities were examined by superoxide and hydroxyl radical scavenging activities of ginseng and cultivated wild ginseng extracts. Results : 1. In the superoxide radical scavenging activities of ginseng and cultivated wild ginseng extracts, antioxidant activities of cultivated wild ginseng extracts was showed higher than cultivated ginseng in the concentration of 0.25 and 0.50㎎/㎖. 2. In the hydroxyl radical scavenging activities of ginseng and cultivated wild ginseng extracts, antioxidant activities of cultivated wild ginseng extracts was showed higher than cultivated ginseng in the concentration of 1.0, 2.5, and 5.0㎎/㎖. Conclusions : In summary, the results of this study demonstrate that cultivated wild ginseng extracts had higher antioxidant activities to cultivated ginseng.

Requirements for superoxide-dependent tyrosine hydroperoxide formation in peptides

DEFF Research Database (Denmark)

Winterbourn, Christine C; Parsons-Mair, Helena N; Gebicki, Silvia

2004-01-01

Superoxide reacts rapidly with other radicals, but these reactions have received little attention in the context of oxidative stress. For tyrosyl radicals, reaction with superoxide is 3-fold faster than dimerization, and forms the addition product tyrosine hydroperoxide. We have explored structural...... requirements for hydroperoxide formation using tyrosine analogues and di- and tri-peptides. Superoxide and phenoxyl radicals were generated using xanthine oxidase, peroxidase and the respective tyrosine derivative, or by gamma-radiation. Peroxides were measured using FeSO4/Xylenol Orange. Tyrosine and tyramine...... formed stable hydroperoxides, but N-acetyltyrosine and p-hydroxyphenylacetic acid did not, demonstrating a requirement for a free amino group. Using [14C]tyrosine, the hydroperoxide and dityrosine were formed at a molar ratio of 1.8:1. Studies with pre-formed hydroperoxides, and measurements of substrate...

The strong influence of the solvent on the electron spin resonance spectra of semiquinone radical anions

DEFF Research Database (Denmark)

Spanget-Larsen, Jens

2013-01-01

). The proton hyperfine constants predicted for the chrysazin semiquinone radical anion were highly sensitive to the assumed dielectric constant ε of the solvent continuum, inverting the relative magnitudes of the hyperfine constants and thereby leading to agreement with the observed data published by Stegmann...

Study of radicals, clusters and transition state species by anion photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Arnold, Don Wesley [Univ. of California, Berkeley, CA (United States)

1994-08-01

Free radicals, elemental and van der Waals clusters and transition state species for bimolecular chemical reactions are investigated using anion photoelectron spectroscopy. Several low-lying electronic states of ozone have been identified via photoelectron spectroscopy of O₃^-. A characterization of these states is important to models for atmospheric ozone reaction kinetics. The fluoroformyloxyl radical, FCO₂, has been investigated, providing vibrational frequencies and energies for two electronic states. The technique has also been employed to make the first direct observation and characterization of the NNO₂ molecule. Several electronic states are observed for this species which is believed to play a role as a reactive intermediate in the N + NO₂ reaction. The experimental results for all three of these radicals are supplemented by ab initio investigations of their molecular properties. The clusters investigations include studies of elemental carbon clusters (C₂^- - C₁₁^-), and van der Waals clusters (X^-(CO₂)_n, X = I, Br, Cl; n {le} 13 and I^- (N₂O)_n=1--11). Primarily linear clusters are observed for the smaller carbon clusters, while the spectra of the larger clusters contain contribution from cyclic anion photodetachment. Very interesting ion-solvent interactions are observed in the X^-(CO₂)n clusters. The transition state regions for several bimolecular chemical reactions have also been investigated by photodetachment of a negative ion precursor possessing a geometry similar to that of the transition state species. These spectra show features which are assigned to motions of the unstable neutral complex existing between reactants and products.

Neutrophil superoxide-anion generating capacity in chronic smoking ...

Indian Academy of Sciences (India)

Unknown

To this purpose, we randomly assigned 128 male chronic smokers (37 ± 21 pack years of smoking) ... Secondly, in non-smoking human subjects we have recently shown ... therapy in chronic smoking affects superoxide generating capacity of ...

Role of nitric oxide and superoxide in Giardia lamblia killing

Directory of Open Access Journals (Sweden)

P.D. Fernandes

1997-01-01

Full Text Available Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine. Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites. This effect was inhibited (>90% by an NO synthase inhibitor (200 µM and unaffected by superoxide dismutase (SOD, 300 U/ml. Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP and sodium nitroprusside (SNP in a dose-dependent manner (LD50 300 and 50 µM, respectively. A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1, did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml was added simultaneously with SIN-1 to Giardia, a significant trophozoite-killing effect was observed (~35% dead trophozoites at 1 mM. The mixture of SNAP or SNP with superoxide anion, which yields peroxynitrite, abolished the trophozoite killing induced by NO donors. Authentic peroxynitrite only killed trophozoites at very high concentrations (3 mM. These results indicate that NO accounts for Giardia trophozoite killing and this effect is not mediated by peroxynitrite

Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

International Nuclear Information System (INIS)

Orona, N.S.; Tasat, D.R.

2012-01-01

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO 3 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO 3 . We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O 2 − ). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O 2 − may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O 2 − may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through all the range of doses tested.

Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

Energy Technology Data Exchange (ETDEWEB)

Orona, N.S. [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142 (1122), Buenos Aires (Argentina)

2012-06-15

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO{sub 3} 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO{sub 3}. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O{sub 2}{sup −}). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O{sub 2}{sup −} may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O{sub 2}{sup −} may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through

(-)-Xanthienopyran, a new inhibitor of superoxide anion generation by activated neutrophils, and further constituents of the seeds of Xanthium strumarium.

Science.gov (United States)

Lee, Chia-Lin; Huang, Po-Ching; Hsieh, Pei-Wen; Hwang, Tsong-Long; Hou, Yu-Yi; Chang, Fang-Rong; Wu, Yang-Chang

2008-08-01

The dried seeds of XANTHIUM STRUMARIUM (Asteraceae) are used after thorough stir-frying as an ingredient in traditional Chinese medicines for relieving allergy. Two new compounds, xanthialdehyde ( 2) and (-)-xanthienopyran ( 7), as well as 26 known compounds were isolated in the present study. The structures of the isolates were elucidated by spectroscopic methods. Among them, compound 7 exhibited significant selective inhibition of superoxide anion generation by human neutrophils induced by formyl- L-methionyl- L-leucyl- L-phenylalanine, with an IC50 value of 1.72 microg/mL.

Studies of radiation-produced radicals and radical ions. Progress report, June 1, 1981-August 31, 1982

International Nuclear Information System (INIS)

Williams, T.F.

1982-01-01

The discovery and characterization of novel radical ions produced by the γ irradiation of solids continues to be a fertile field for investigation. This Progress Report describes the generation and ESR identification of several new paramagnetic species, some of which have long been sought as important intermediates in radiation chemistry. We have also contributed to a general theoretical problem in ESR spectroscopy. Solid-state studies of electron attachment reactions, both non-dissociative and dissociative, reveal interesting structural and chemical information about the molecular nature of these processes for simple compounds. In particular, ESR measurements of the spin distribution in the products allow a fairly sharp distinction to be drawn between radical anions and radical-anion pairs or adducts. Dimer radical anion formation can also take place but the crystal structure plays a role in this process, as expected. Some radical anions undergo photolysis to give radical-anion pairs which may then revert back to the original radical anion by a thermal reaction. The chemistry of these reversible processes is made more intricate by a competing reaction in which the radical abstracts a hydrogen atom from a neighboring molecule. However, the unraveling of this complication has also served to extend our knowledge of the role of quantum tunneling in chemical reactions. The results of this investigation testify to the potential of solid-state techniques for the study of novel and frangible radical ions. Progress in this field shows no sign of abating, as witness the recent discovery of perfluorocycloalkane radical anions and alkane radical cations

Inhibition of Procarcinogen Activating Enzyme CYP1A2 Activity and Free Radical Formation by Caffeic Acid and its Amide Analogues.

Science.gov (United States)

Narongchai, Paitoon; Niwatananun, Kanokporn; Narongchai, Siripun; Kusirisin, Winthana; Jaikang, Churdsak

2016-01-01

Caffeic acid (CAF) and its amide analogues, ethyl 1-(3',4'-dihydroxyphenyl) propen amide (EDPA), phenethyl 1-(3',4'-dihydroxyphenyl) propen amide (PEDPA), phenmethyl 1- (3',4'-dihydroxyphenyl) propen amide (PMDPA) and octyl 1-(3',4'-dihydroxyphenyl) propen amide (ODPA) were investigated for the inhibition of procarcinogen activating enzyme. CYP1A2 and scavenging activity on formation of nitric oxide, superoxide anion, DPPH radical and hydroxyl radical. It was found that they inhibited CYP1A2 enzyme by uncompetitive inhibition. Apparent Ki values of CAF, EDPA, PEDPA, PMDPA and ODPA were 0.59, 0.39, 0.45, 0.75 and 0.80 µM, respectively suggesting potent inhibitors of CYP1A2. Moreover, they potentially scavenged nitric oxide radical with IC 50 values of 0.12, 0.22, 0.28, 0.22 and 0.51 mM, respectively. The IC50 values of superoxide anion scavenging were 0.20, 0.22, 0.44, 2.18 and 2.50 mM, respectively. 1, 1- diphenyl-2- picrylhydrazyl (DPPH) radical-scavenging ability, shown as IC50 values, were 0.41, 0.29, 0.30, 0.89 and 0.84 mM, respectively. Moreover, the hydroxyl radical scavenging in vitro model was shown as IC50 values of 23.22, 21.06, 17.10, 17.21 and 15.81 µM, respectively. From our results, caffeic acid and its amide analogues are in vitro inhibitors of human CYP1A2 catalytic activity and free radical formation. They may be useful to be developed as potential chemopreventive agents that block CYP1A2-mediated chemical carcinogenesis.

The Effect of Nitrogen-Doped ATO Nanotubes on Radical Multiplication of Buffer Media by Visible Light Photocatalysis Rather UV

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Kan-Hung Hu

2012-01-01

Full Text Available The use of TiO2 in photodynamic therapy for the treatment of cancer has generally been studied in cultured cancer cells in serum-containing RPMI 1640 medium under visible light application rather than ultraviolet (UV light. An ordered channel array of N-doped anodic titanium dioxide (ATO has been successfully made for visible light application. ATO nanotubes in the anatase form with a length of 10 μm are more effective than nanotubes of 1.8 μm in length as a photocatalyst for radical multiplication in buffer solution by generating hydroxyl radicals and superoxide radical anions under UV-A exposure. Only the N-doped ATO is applicable to visible light photocatalysis for radical multiplication in RPMI 1640+1% FBS and acrylamide, a free radical carrier.

Nitric oxide and superoxide anion production in monocytes from children exposed to arsenic and lead in region Lagunera, Mexico

International Nuclear Information System (INIS)

Pineda-Zavaleta, Ana Patricia; Garcia-Vargas, Gonzalo; Borja-Aburto, Victor H.; Acosta-Saavedra, Leonor C.; Vera Aguilar, Eunice; Gomez-Munoz, Aristides; Cebrian, Mariano E.; Calderon-Aranda, Emma S.

2004-01-01

We evaluated in Mexican children environmentally exposed to arsenic and lead monocyte nitric oxide (NO) and superoxide anion production in response to direct activation with interferon-γ (IFN-γ) + lipopolysaccharide (LPS). The integrity of Th1-regulated cellular immune response when monocytes were indirectly activated was also evaluated. Most children lived near a primary lead smelter. Lead and arsenic contamination in soil and dust by far exceeded background levels. As levels in water were between 10 and 30 ppb. Most children (93%) had urinary arsenic (AsU) concentrations above 50 μg/l (range 16.75-465.75) and 65% had lead blood levels (PbB) above 10 μg/dl (range 3.47-49.19). Multivariate analyses showed that NO production in monocytes activated indirectly was negatively associated with both PbB and AsU. Superoxide production in directly activated monocytes was negatively associated with AsU but positively associated with PbB. The models including the interaction term for AsU and PbB suggested the possibility of a negative interaction for NO production and a positive interaction for superoxide. There were indications of differential gender-based associations, NO production in indirectly activated monocytes obtained from girls was negatively associated with AsU but not with PbB. Superoxide production was positively associated with PbB in both directly and indirectly activated monocytes from boys but the latter was negatively associated with AsU. These effects are consistent with immune system abnormalities observed in human populations exposed to Pb or As. Further studies in larger populations are required to characterize As and Pb interactions and the mechanism(s) underlying the observed effects

Radical reactions in vivo - an overview

International Nuclear Information System (INIS)

Saran, M.; Bors, W.

1990-01-01

Generation of radicals in vivo depends on metabolic activities. The reactions are usually influenced by (i) the presence and concentration of oxygen, (ii) the availability of transition metals (effects of binding and compartimentalization), (iii) the level of reductants and antioxidants (e.g. nutritional effects). The effects of radicals are thought to be due to (i) membrane damage (affecting passive or active transport through altered fluidity/function interrelationships, intercellular messenging through modifications in the synthesis of prostaglandins and leukotrienes); (ii) protein damage (e.g. affecting membrane transporters, channel proteins, receptor or regulatory proteins, immunomodulators); (iii) damage to DNA. Defense mechanisms consist of (i) prevention of the 'spreading' of primary damage by low molecular weight antioxidants (e.g. vitamin E, GSH, vitamin C, β-carotene, uric acid); (ii) prevention or limitation of 'secondary' damage by enzymes (e.g. GSH-peroxidase, catalase, superoxide dismutase, DT-diaphorase) and/or chelators; (iii) repair processes, e.g. lipid degradation/membrane repair enzymes (phospholipases, peroxidases, some transferases and reductases), protein disposal or repair enzymes (proteases, GSSG-reductase), DNA degradation or repair enzymes (exonucleases III, endonucleases III and IV, glycosylases, polymerases). Recent hypotheses on a messenging function of the superoxide anion O 2 - are discussed and possible implications of cross-reactions between O 2 - and nitric oxide (endothelium-derived relaxing factor EDRF) are shortly mentioned. (orig.)

Oxygen radical detoxification enzymes in doxorubicin-sensitive and -resistant P388 murine leukemia cells

International Nuclear Information System (INIS)

Ramu, A.; Cohen, L.; Glaubiger, D.

1984-01-01

One of the proposed mechanisms for the cytotoxic effects of anthracycline compounds suggests that the effect is mediated through the formation of intracellular superoxide radicals. It is therefore possible that doxorubicin resistance is associated with increased intracellular enzyme capacity to convert these superoxide radicals to inactive metabolites. We have measured the relative activities of superoxide dismutase, glutathione peroxidase, and catalase in P388 mouse leukemia cells and in a doxorubicin-resistant subline. Since oxygen-reactive metabolites also play a role in mediating the cytotoxicity of ionizing radiation, the radiosensitivity of both cell lines was also studied. No significant differences in superoxide dismutase activity between these cell lines was observed, indicating that they have a similar capacity to convert superoxide anion radicals to hydrogen peroxide. P388 cells that are resistant to doxorubicin have 1.5 times the glutathione content and 1.5 times the activity of glutathione peroxidase measured in drug-sensitive P388 cells. However, incubation with 1-chloro-2,4-dinitrobenzene, which covalently binds glutathione, had no effect on the sensitivity of either cell line to doxorubicin. Measured catalase activity in drug-resistant P388 cells was one-third of the activity measured in doxorubicin-sensitive P388 cells. The activity of this enzyme was much higher than that of glutathione peroxidase in terms of H 2 O 2 deactivation in both cell lines. It is therefore unlikely that doxorubicin-resistant P388 cells have an increased ability to detoxify reactive oxygen metabolites when compared to drug-sensitive cells. Doxorubicin-resistant P388 cells were significantly more sensitive to X-irradiation than were drug-sensitive P388 cells. These observations suggest that the difference in catalase activity in these cell lines may be associated with the observed differences in radiosensitivity

Importance of sulfate radical anion formation and chemistry in heterogeneous OH oxidation of sodium methyl sulfate, the smallest organosulfate

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K. C. Kwong

2018-02-01

Full Text Available Organosulfates are important organosulfur compounds present in atmospheric particles. While the abundance, composition, and formation mechanisms of organosulfates have been extensively investigated, it remains unclear how they transform and evolve throughout their atmospheric lifetime. To acquire a fundamental understanding of how organosulfates chemically transform in the atmosphere, this work investigates the heterogeneous OH radical-initiated oxidation of sodium methyl sulfate (CH3SO4Na droplets, the smallest organosulfate detected in atmospheric particles, using an aerosol flow tube reactor at a high relative humidity (RH of 85 %. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (direct analysis in real time, DART coupled with a high-resolution mass spectrometer showed that neither functionalization nor fragmentation products are detected. Instead, the ion signal intensity of the bisulfate ion (HSO4− has been found to increase significantly after OH oxidation. We postulate that sodium methyl sulfate tends to fragment into a formaldehyde (CH2O and a sulfate radical anion (SO4 ⋅ − upon OH oxidation. The formaldehyde is likely partitioned back to the gas phase due to its high volatility. The sulfate radical anion, similar to OH radical, can abstract a hydrogen atom from neighboring sodium methyl sulfate to form the bisulfate ion, contributing to the secondary chemistry. Kinetic measurements show that the heterogeneous OH reaction rate constant, k, is (3.79 ± 0.19  ×  10−13 cm3 molecule−1 s−1 with an effective OH uptake coefficient, γeff, of 0.17 ± 0.03. While about 40 % of sodium methyl sulfate is being oxidized at the maximum OH exposure (1.27  ×  1012 molecule cm−3 s, only a 3 % decrease in particle diameter is observed. This can be attributed to a small fraction of particle mass lost via the formation and volatilization of formaldehyde. Overall, we

Effects of sphingosine and sphingosine analogues on the free radical production by stimulated neutrophils: ESR and chemiluminescence studies

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A. Mouithys-Mickalad

1997-01-01

Full Text Available Sphingolipids inhibit the activation of the neutrophil (PMN NADPH oxidase by protein kinase C pathway. By electron spin resonance spectroscopy (ESR and chemiluminescence (CL, we studied the effects of sphingosine (SPN and ceramide analogues on phorbol 12-myristate 13-acetate (PMA, 5 × 10-7M stimulated PMN (6 × 106 cells. By ESR with spin trapping (100 mM DMPO: 5,5-dimethyl-1-pyrroline-Noxide, we showed that SPN (5 to 8 × 10-6M, C2-ceramide (N-acetyl SPN and C6-ceramide (N-hexanoyl SPN at the final concentration of 2 × 10-5 and 2 × 10-4M inhibit the production of free radicals by stimulated PMN. The ESR spectrum of stimulated PMN was that of DMPO-superoxide anion spin adduct. Inhibition by 5 × 10-6M SPN was equivalent to that of 30 U/ml SOD. SPN (5 to 8 × 10-6M has no effect on in vitro systems generating superoxide anion (xanthine 50 mM/xanthine oxidase 110 mU/ml or hydroxyl radical (Fenton reaction: 88 mM H2O2, 0.01 mM Fe2+ and 0.01 mM EDTA. SPN and N-acetyl SPN also inhibited the CL of PMA stimulated PMN in a dose dependent manner (from 2 × 10-6 to 10-5M, but N-hexanoyl SPN was less active (from 2 × 10-5 to 2 × 10-4M. These effects were compared with those of known PMN inhibitors, superoxide dismutase, catalase and azide. SPN was a better inhibitor compared with these agents. The complete inhibition by SPN of ESR signal and CL of stimulated PMN confirms that this compound or one of its metabolites act at the level of NADPH-oxidase, the key enzyme responsible for production of oxygen-derived free radicals.

Neutrophil superoxide-anion generating capacity in chronic smoking ...

Indian Academy of Sciences (India)

We investigated whether long-term -tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 ± 21 pack years of smoking) to treatment with placebo ( = 64) or -tocopherol (400 IU dL--tocopherol daily, ...

Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

Energy Technology Data Exchange (ETDEWEB)

Yoshinaka, T; Yano, K; Yamaguchi, H [Tokyo Univ. (Japan). Faculty of Agriculture

1976-01-01

The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showedrelatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells.

Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

International Nuclear Information System (INIS)

Yoshinaka, Taeko; Yano, Keiji; Yamaguchi, Hikoyuki

1976-01-01

The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showed relatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells. (Kako, I.)

Role of macrophages and oxygen radicals in IgA induced lung injury in the rat

International Nuclear Information System (INIS)

Johnson, K.J.; Ward, P.A.; Kunkel, R.G.; Wilson, B.S.

1986-01-01

Acute lung injury in the rat has been induced by the instillation of affinity-purified mouse monoclonal IgA antibody with specific reactivity to dinitrophenol (DNP) coupled to albumin. This model of lung injury requires an intact complement system but not neutrophils, and evidence suggests that pulmonary macrophages are the critical effector cell. Macrophages retrievable from the lungs of the IgA immune complex treated rats are considerably increased in number as compared to control animals which received only the antibody. In addition these cells show evidence of activation in vivo with greater spontaneous generation of the superoxide anion (O 2 - ) as well as significantly enhanced O 2 - response in the presence of a second stimulus. Inhibition studies in vivo suggest that the lung injury is mediated by oxygen radical generation by the pulmonary macrophages. Pretreatment of rats with superoxide dismutase (SOD), catalase, the iron chelator deferoxamine or the hydroxyl radical scavenger dimethyl sulfoxide (DMSO) all markedly suppressed the development of the lung injury. In summary, these studies suggest that IgA immune complex injury in the rat lung is mediated by oxygen radical formation from pulmonary macrophages

Superoxide dismutating molecules rescue the toxic effects of PINK1 and parkin loss.

Science.gov (United States)

Biosa, Alice; Sanchez-Martinez, Alvaro; Filograna, Roberta; Terriente-Felix, Ana; Alam, Sarah M; Beltramini, Mariano; Bubacco, Luigi; Bisaglia, Marco; Whitworth, Alexander J

2018-05-01

Reactive oxygen species exert important functions in regulating several cellular signalling pathways. However, an excessive accumulation of reactive oxygen species can perturb the redox homeostasis leading to oxidative stress, a condition which has been associated to many neurodegenerative disorders. Accordingly, alterations in the redox state of cells and mitochondrial homeostasis are established hallmarks in both familial and sporadic Parkinson's disease cases. PINK1 and Parkin are two genes which account for a large fraction of autosomal recessive early-onset forms of Parkinson's disease and are now firmly associated to both mitochondria and redox homeostasis. In this study we explored the hypothesis that superoxide anions participate in the generation of the Parkin and PINK1 associated phenotypic effect by testing the capacity of endogenous and exogenous superoxide dismutating molecules to rescue the toxic effects induced by loss of PINK1 or Parkin, in both cellular and fly models. Our results demonstrate the positive effect of an increased level of superoxide dismutase proteins on the pathological phenotypes, both in vitro and in vivo. A more pronounced effectiveness for mitochondrial SOD2 activity points to the superoxide radicals generated in the mitochondrial matrix as the prime suspect in the definition of the observed phenotypes. Moreover, we also demonstrate the efficacy of a SOD-mimetic compound, M40403, to partially ameliorate PINK1/Parkin phenotypes in vitro and in vivo. These results support the further exploration of SOD-mimetic compounds as a therapeutic strategy against Parkinson's disease.

The Synthesis and Evaluation of Novel Hydroxyl Substituted Chalcone Analogs with in Vitro Anti-Free Radicals Pharmacological Activity and in Vivo Anti-Oxidation Activity in a Free Radical-Injury Alzheimer’s Model

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Ying Pan

2013-01-01

Full Text Available Alzheimer’s disease (AD pathogenesis involves an imbalance between free radical formation and destruction. In order to obtain a novel preclinical anti-AD drug candidate, we synthesized a series of novel hydroxyl chalcone analogs which possessed anti-free radical activity, and screened their effects on scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH and OH free radicals in vitro. Compound C7, 4,2'-dihydroxy-3,5-dimethoxychalcone was found to have potent activity in these anti-free radical activity tests. Further research revealed that C7 could elevate glutathione peroxidase (GSH-PX and super oxide dismutase (SOD levels and lower malonaldehyde (MDA level in vivo in the Alzheimer’s model. The indication of C7’s effect on AD needs further study.

Formation and scavenging of superoxide in chloroplasts, with relation to injury by sulfur dioxide

Energy Technology Data Exchange (ETDEWEB)

Asada, K

1980-01-01

Injury of plant leaf cells by sulfur dioxide-exposure is greater in day time than in night. A hypothesis is proposed that the free radical chain oxidation of sulfite is initiated by the superoxide radicals (O/sub 2//sup -/) produced in illuminated chloroplasts, and that the resulting amplified production of O/sub 2//sup -/, the hydroxyl radicals and the bisulfite radicals causes the injury of leaf tissues. In this review, the production of O/sub 2//sup -/ in illuminated chloroplasts and scavenging of O/sub 2//sup -/ by superoxide dismutase and their relation to oxidation of sulfite in chloroplasts are discussed. Superoxide dismutase in chloroplasts plays an important role in protecting leaf cells from injury by sulfur dioxide.

Physical and chemical stability of different formulations with superoxide dismutase.

Science.gov (United States)

Di Mambro, V M; Campos, P M B G Maia; Fonseca, M J V

2004-10-01

Topical formulations with superoxide dismutase (SOD), a scavenger of superoxide radicals, have proved to be effective against some skin diseases. Nevertheless, formulations with proteins are susceptible to both chemical and physical instability. Three different formulations (anionic and non-ionic gel and emulsion) were developed and supplemented with SOD in order to determine the most stable formulation that would maintain SOD activity. Physical stability was evaluated by assessing the rheological behavior of the formulations stored at room temperature, 37 and 45 degrees C. Chemical stability was evaluated by the measurement of enzymatic activity in the formulations stored at room temperature and at 45 degrees C. Formulations showed a flow index less than one, characterizing pseudoplastic behavior. There was no significant difference in initial values of flow index, tixotropy or minimum apparent viscosity. Neither gel showed significant changes in minimum apparent viscosity concerning storage time or temperature, as well, SOD presence and its activity. The emulsion showed decreased viscosity by the 28th day, but no significant changes concerning storage temperature or SOD presence, although it showed a decreased activity. The addition of SOD to the formulations studied did not affect their physical stability but gel formulations seem to be better bases for enzyme addition.

SYNTHESIS OF BLOCK COPOLYMER BY INTEGRATED LIVING ANIONIC POLYMERIZATION-ATOM TRANSFER RADICAL POLYMERIZATION (ATRP)

Institute of Scientific and Technical Information of China (English)

Bing Liu; Feng Liu; Ning Luo; Sheng-kang Ying; Qing Liu

2000-01-01

Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene)oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as initiator.Then the PS-CH2CH2OCOCCl3 (PS-Cl3) or P(S-b-B)-CH2CH2O-COCCl3 (PSB-Cl3) was used as the macroinitiator in the polymerization of (meth)acrylates in the presence of CuX/bpy. AB diblock and ABC triblock copolymers were prepared by the integrated living anionic polymerization (LAP)-atom transfer radical polymerization (ATRP). The structures of the PSB-Cl3 and the P(S-b-MMA) were identified by FTIR and 1H-NMR spectrum, respectively. A new way to design block copolymers (the combination of LAP and ATRP) was developed.

Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur-Iodine and Selenium-Iodine Exchange.

Science.gov (United States)

Wang, Ming; Fan, Qiaoling; Jiang, Xuefeng

2016-11-04

A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S-I and Se-I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and [1]benzothieno[3,2-b][1]benzoselenophene (BTBS) were efficiently established.

Synthesis and Blastocyst Implantation Inhibition Potential of Lupeol Derivatives in Female Mice

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Anita Mahapatra

2015-06-01

Full Text Available Blastocyst implantation which is analogous to pro-inflammatory response, mediated by different inflammatory mediators and ovarian hormones found to be an effective target for the development of emergency contraceptives. In the present study, a series of derivatives an anti-inflammatory natural scaffold, lupeol were synthesized under mild reaction conditions and good yield. All the compounds were evaluated for acute anti-inflammation. The three active compounds with 62-92% edema protection were screened for chronic anti-inflammation. The analogue 3-(p-chlorocinnamoyl lupeol ( 2 with potent anti-inflammatory activity (85% protection was evaluated for t he anti-implantation activity by studying changes in superoxide dismutase (SOD and lipid peroxidation (LPO levels, visualization of implantation site and anti-estrogenic activity. As expected, a sharp decrease in superoxide anion radical and increase in SOD activity was seen in the endometrium of treated animals. Also no implantation sites were observed in the uterus of treated animals. The active compound also exhibited anti-estrogenic activity.

Antioxidant and Antiproliferative Potential of Fruiting Bodies of the Wild-Growing King Bolete Mushroom, Boletus edulis (Agaricomycetes), from Western Serbia.

Science.gov (United States)

Novakovic, Aleksandra; Karaman, Maja; Kaisarevic, Sonja; Radusin, Tanja; Llic, Nebojsa

2017-01-01

The aim of this work was to study the bioactivity of crude aqueous and ethanolic extracts of Boletus edulis prepared from caps and stipes of wild-growing basidiocarps collected from the Prijepolje region (western Serbia). The bioactivity screening included antioxidant (2,2-diphenyl-l-picrylhydrazyl [DPPH], nitric oxide, super-oxide anion*, and hydroxyl radicals and ferric-reducing antioxidant power) and antiproliferative MTT assays (human breast MCF-7 cancer cell line). In addition, all extracts were primarily characterized by ultraviolet/visible spectrophotometry to determine total phenolic and flavonoid contents. The highest anti-DPPH and anti-hydroxyl radical activity were observed in aqueous B. edulis extract from the caps (half maximal inhibitory concentration [IC50] = 50.97 μg/ mL and 2.05 μg/mL, respectively), whereas the highest anti-nitric oxide radical activity was observed in aqueous B. edulis extract from the stipes (IC50 = 10.74 μg/mL). The ethanolic extract obtained from the mushroom stipe showed higher anti-superoxide anion radical activity (IC50 = 9.84 μg/mL) and ferric-reducing antioxidant power (22.14 mg ascorbic acid equivalents/g dry weight) compared with aqueous extracts. Total phenolic content for all extracts was similar but total flavonoid content was significantly higher in the aqueous B. edulis extract from the caps (4.5 mg quercetin equivalents/g dry weight). All crude extracts showed activity against the MCF-7 cell line, with the ethanolic extract of B. edulis prepared from stipes (IC50 = 56 μg/mL) being the most potent. This is, to our knowledge, the first report of the antiproliferative effects of crude aqueous and ethanolic extracts prepared from caps and stipes of wild-growing basidiocarps of B. edulis on the human breast MCF-7 cancer cell line.

Microhydration of cytosine and its radical anion: Cytosine.(H2O)n (n=1-5)

Science.gov (United States)

Kim, Sunghwan; Schaefer, Henry F.

2007-02-01

Microhydration effects on cytosine and its radical anion have been investigated theoretically, by explicitly considering various structures of cytosine complexes with up to five water molecules. Each successive water molecule (through n =5) is bound by 7-10kcalmol-1 to the relevant cytosine complex. The hydration energies are uniformly higher for the analogous anion systems. While the predicted vertical detachment energy (VDE) of the isolated cytosine is only 0.48eV, it is predicted to increase to 1.27eV for the lowest-lying pentahydrate of cytosine. The adiabatic electron affinity (AEA) of cytosine was also found to increase from 0.03to0.61eV for the pentahydrate, implying that the cytosine anion, while questionable in the gas phase, is bound in aqueous solution. Both the VDE and AEA values for cytosine are smaller than those of uracil and thymine for a given hydration number. These results are in qualitative agreement with available experimental results from photodetachment-photoelectron spectroscopy studies of Schiedt et al. [Chem. Phys. 239, 511 (1998)].

Understanding Free Radicals: Isolating Active Thylakoid Membranes and Purifying the Cytochrome b6f Complex for Superoxide Generation Studies

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Jason Stofleth

2012-01-01

Full Text Available All life persists in an environment that is rich in molecular oxygen. The production of oxygen free radicals, or superoxide, is a necessary consequence of the biogenesis of energy in cells. Both mitochondrial and photosynthetic electron transport chains have been found to produce superoxide associated with cell differentiation, proliferation, and cell death, thereby contributing to the effects of aging. Aerobic respiration in mitochondria consumes oxygen, whereas photosynthesis in chloroplasts or cyanobacteria produces oxygen. The increased concentration of molecular oxygen may serve to allow greater availability for the production of superoxide by cytochrome bc complexes in photosynthetic membranes compared to those of mitochondrial membranes. The isolation of well-coupled chloroplasts, containing the cytochrome b6f complex of oxygenic photosynthesis, is a vital initial step in the process of comparing the rate of production of superoxide to those of the homologous cytochrome bc1 complex of aerobic respiration. It is necessary to determine if the isolated chloroplasts have retained their oxygengenerating capability after isolation by an oxygen evolution assay with a Clark-type electrode. A necessary second step, which is the isolation of cytochrome b6f from spinach, has yet to be successfully performed. Oxygen measurements taken from chloroplasts in the presence of the uncoupler, NH4Cl, exhibited a rate of oxygen evolution over three times greater at 344 +/- 18 μmol O2/mg Chlorophyll a/hr than the rate of oxygen evolution without uncoupler at 109 +/- 29 μmol O2/mg Chlorophyll a/hr. These data demonstrate that the technique used to isolate spinach chloroplasts preserves their light-driven electron-transport activity, making them reliable for future superoxide assays.

The scavenging of free radical and oxygen species activities and hydration capacity of collagen hydrolysates from walleye pollock ( Theragra chalcogramma) skin

Science.gov (United States)

Zhuang, Yongliang; Li, Bafang; Zhao, Xue

2009-06-01

Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock ( Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.

EPR studies of the vitamin K 1 semiquinone radical anion. Comparison to the electron acceptor A 1 in green plant photosystem I

Science.gov (United States)

Thurnauer, Marion C.; Brown, James W.; Gast, P.; Feezel, Laura L.

Suggestions that the electron acceptor, A 1, in Photosystem I is a quinone have come from both optical and epr experiments. Vitamin K 1 (phylloquinone) is present in the PSI complex with a stoichiometry of two molecules per reaction center. In order to determine if A 1 can be identified with vitamin K 1, X-band and Q-band epr properties of the vitamin K 1 radical anion in frozen alcohol solutions are examined. The results are compared to the epr properties that have been observed for the reduced A 1 acceptor in vivo. The g-values obtained for the vitamin K 1 radical anion are consistent with identifying A 1 with vitamin K 1.

Superoxide produced by Kupffer cells is an essential effector in concanavalin A-induced hepatitis in mice.

Science.gov (United States)

Nakashima, Hiroyuki; Kinoshita, Manabu; Nakashima, Masahiro; Habu, Yoshiko; Shono, Satoshi; Uchida, Takefumi; Shinomiya, Nariyoshi; Seki, Shuhji

2008-12-01

Although concanavalin A (Con-A)-induced experimental hepatitis is thought to be induced by activated T cells, natural killer T (NKT) cells, and cytokines, precise mechanisms are still unknown. In the current study, we investigated the roles of Kupffer cells, NKT cells, FasL, tumor necrosis factor (TNF), and superoxide in Con-A hepatitis in C57BL/6 mice. Removal of Kupffer cells using gadolinium chloride (GdCl(3)) from the liver completely inhibited Con-A hepatitis, whereas increased serum TNF and IFN-gamma levels were not inhibited at all. Unexpectedly, anti-FasL antibody pretreatment did not inhibit Con-A hepatitis, whereas it inhibited hepatic injury induced by a synthetic ligand of NKT cells, alpha-galactosylceramide. Furthermore, GdCl(3) pretreatment changed neither the activation-induced down-regulation of NK1.1 antigens as well as T cell receptors of NKT cells nor the increased expression of the CD69 activation antigen of hepatic T cells. CD68(+) Kupffer cells greatly increased in proportion in the early phase after Con-A injection; this increase was abrogated by GdCl(3) pretreatment. Anti-TNF antibody (Ab) pretreatment did not inhibit the increase of Kupffer cells, but it effectively suppressed superoxide/reactive oxygen production from Kupffer cells and the resulting hepatic injury. Conversely, depletion of NKT cells in mice by NK1.1 Ab pretreatment did suppress both the increase of CD68(+) Kupffer cells and Con-A hepatitis. Consistently, the diminution of oxygen radicals produced by Kupffer cells by use of free radical scavengers greatly inhibited Con-A hepatitis without suppressing cytokine production. However, adoptive transfer experiments also indicate that a close interaction/cooperation of Kupffer cells with NKT cells is essential for Con-A hepatitis. Superoxide produced by Kupffer cells may be the essential effector in Con-A hepatitis, and TNF and NKT cells support their activation and superoxide production.

Biomaterial-induced alterations of neutrophil superoxide production.

Science.gov (United States)

Kaplan, S S; Basford, R E; Mora, E; Jeong, M H; Simmons, R L

1992-08-01

Because periprosthetic infection remains a vexing problem for patients receiving implanted devices, we evaluated the effect of several materials on neutrophil free radical production. Human peripheral blood neutrophils were incubated with several sterile, lipopolysaccharide (LPS)-free biomaterials used in surgically implantable prosthetic devices: polyurethane, woven dacron, and velcro. Free radical formation as the superoxide (O2-) anion was evaluated by cytochrome c reduction in neutrophils that were exposed to the materials and then removed and in neutrophils allowed to remain in association with the materials. Neutrophils exposed to polyurethane or woven dacron for 30 or 60 min and then removed consistently exhibited an enhanced release of O2- after simulation via receptor engagement with formyl methionyl-leucyl-phenylalanine. Enhanced reactivity to stimulation via protein kinase C with phorbol myristate acetate, however, was not consistently observed. The cells evaluated for O2- release during continuous association with the biomaterials showed enhanced metabolic activity during short periods of association (especially with polyurethane and woven dacron). Although O2- release by neutrophils in association with these materials decreased with longer periods of incubation, it was not obliterated. These studies, therefore, show that several commonly used biomaterials activate neutrophils soon after exposure and that this activated state diminishes with prolonged exposure but nevertheless remains measurable. The diminishing level of activity with prolonged exposure, however, suggests that ultimately a depletion of reactivity may occur and may result in increased susceptibility to periprosthetic infection.

X-ray absorption spectroscopy of ultramarine pigments: A new analytical method for the polysulfide radical anion S3- chromophore

International Nuclear Information System (INIS)

Fleet, Michael E.; Liu, Xi

2010-01-01

Blue and mauve ultramarine artists' pigments and their heat-treated products have been investigated by sulfur K-edge X-ray absorption. X-ray absorption near-edge structure spectra are dominated by features of reduced sulfur and sulfate species. There is also a pre-peak at about 2468.0 eV which reflects the presence of the unpaired electron on the polysulfide radical anion (S 3 - ). Pre-peak intensity is directly proportional to the depth of blue coloration, and provides a new, independent method for estimating the proportion of ultramarine cage sites occupied by the blue chromophore. The occupancy of the polysulfide radical anion S 3 - is estimated to be 33% in an intense ultramarine blue pigment, 22% in a dark blue ultramarine pigment, and 1% in deep royal blue lazurite from Afghanistan. The more efficient development of color in lazurite is attributed to extensive annealing of the mineral structure in the natural environment.

Formation and fragmentation of radical peptide anions: insights from vacuum ultra violet spectroscopy.

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Brunet, Claire; Antoine, Rodolphe; Dugourd, Philippe; Canon, Francis; Giuliani, Alexandre; Nahon, Laurent

2012-02-01

We have studied the photodissociation of gas-phase deprotonated caerulein anions by vacuum ultraviolet (VUV) photons in the 4.5 to 20 eV range, as provided by the DESIRS beamline at the synchrotron radiation facility SOLEIL (France). Caerulein is a sulphated peptide with three aromatic residues and nine amide bonds. Electron loss is found to be the major relaxation channel at every photon energy. However, an increase in the fragmentation efficiency (neutral losses and peptide backbone cleavages) as a function of the energy is also observed. The oxidized ions, generated by electron photodetachment were further isolated and activated by collision (CID) in a MS(3) scheme. The branching ratios of the different fragments observed by CID as a function of the initial VUV photon energy are found to be independent of the initial photon energy. Thus, there is no memory effect of the initial excitation energy on the fragmentation channels of the oxidized species on the time scale of our tandem MS experiment. We also report photofragment yields as a function of photon energy for doubly deprotonated caerulein ions, for both closed-shell ([M-2H](2-)) non-radical ions and open-shell ([M-3H](2-•)) radical ions. These latter ions are generated by electron photodetachment from [M-3H](3-) precursor ions. The detachment yield increases monotonically with the energy with the appearance of several absorption bands. Spectra for radical and non-radical ions are quite similar in terms of observed bands; however, the VUV fragmentation yield is enhanced by the presence of a radical in caerulein peptides. © American Society for Mass Spectrometry, 2011

[Generation of Superoxide Radicals by Complex III in Heart Mitochondria and Antioxidant Effect of Dinitrosyl Iron Complexes at Different Partial Pressure of Oxygen].

Science.gov (United States)

Dudylina, A L; Ivanova, M V; Shumaev, K B; Ruuge, E K

2016-01-01

The EPR spin-trapping technique and EPR-oximetry were used to study generation of superoxide radicals in heart mitochondria isolated from Wistar rats under conditions of variable oxygen concentration. Lithium phthalocyanine and TEMPONE-15N-D16 were chosen to determine oxygen content in a gas-permeable capillary tube containing mitochondria. TIRON was used as a spin trap. We investigated the influence of different oxygen concentrations in incubation mixture and demonstrated that heart mitochondria can generate superoxide in complex III at different partial pressure of oxygen as well as under the conditions of deep hypoxia (partial pressure of oxygen, but the magnitude and kinetic characteristics of the effect depended on the concentration of the drug.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian Asteraceae plants.

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Shahat, Abdelaaty A; Ibrahim, Abeer Y; Elsaid, Mansour S

2014-07-01

To study the antioxidant properties of crude extract of different Asteraceae plants. The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. Picris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. In most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

An Anion Conductance, the Essential Component of the Hydroxyl-Radical-Induced Ion Current in Plant Roots

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Igor Pottosin

2018-03-01

Full Text Available Oxidative stress signaling is essential for plant adaptation to hostile environments. Previous studies revealed the essentiality of hydroxyl radicals (HO•-induced activation of massive K+ efflux and a smaller Ca2+ influx as an important component of plant adaptation to a broad range of abiotic stresses. Such activation would modify membrane potential making it more negative. Contrary to these expectations, here, we provide experimental evidence that HO• induces a strong depolarization, from −130 to −70 mV, which could only be explained by a substantial HO•-induced efflux of intracellular anions. Application of Gd3+ and NPPB, non-specific blockers of cation and anion conductance, respectively, reduced HO•-induced ion fluxes instantaneously, implying a direct block of the dual conductance. The selectivity of an early instantaneous HO•-induced whole cell current fluctuated from more anionic to more cationic and vice versa, developing a higher cation selectivity at later times. The parallel electroneutral efflux of K+ and anions should underlie a substantial leak of the cellular electrolyte, which may affect the cell’s turgor and metabolic status. The physiological implications of these findings are discussed in the context of cell fate determination, and ROS and cytosolic K+ signaling.

Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity.

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Cheng, Chien-Wei; Chen, Liang-Yü; Chou, Chan-Wei; Liang, Ji-Yuan

2015-07-01

Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized. Copyright © 2015 Elsevier B.V. All rights reserved.

Aliphatic alcohols of illegally produced spirits can act synergistically on superoxide-anion production by human granulocytes.

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Arnyas, Ervin M; Pál, László; Kovács, Csilla; Adány, Róza; McKee, Martin; Szűcs, Sándor

2012-10-01

Aliphatic alcohols present in illegally produced spirits in a large number of low and middle income countries have been implicated in the etiology of chronic liver disease and cirrhosis. Previous studies have confirmed that chronic alcoholism can lead to increased susceptibility to infectious diseases. Reduced superoxide-anion (O(2)·(-)) production by granulocytes could provide a mechanism by which antimicrobial defense is impaired in alcoholics. In vitro experiments have also demonstrated that ethanol can inhibit granulocyte O(2)·(-) generation. Aliphatic alcohols consumed as contaminants of illicit spirits may also influence O(2)·(-) production thereby contributing to a decrease in microbicidal activity. The aim of this study was to investigate this possibility. It measured the O(2)·(-) production by human granulocytes following treatment of the cells with aliphatic alcohol contaminants found in illicit spirits. Granulocytes were isolated from human buffy coats with centrifugal elutriation and then treated with individual aliphatic alcohols and their mixture. The O(2)·(-) production was stimulated with phorbol-12-13-dibutyrate and N-formyl-methionyl-leucyl-phenylalanine (FMLP) and measured by superoxide dismutase inhibitable reduction of ferricytochrome c. Aliphatic alcohols of illegally produced spirits inhibited the FMLP-induced O(2)·(-) production in a concentration dependent manner. They suppressed O(2)·(-) generation at 2.5-40 times lower concentrations when combined than when tested individually. Aliphatic alcohols found in illegally produced spirits can inhibit FMLP-induced O(2)·(-) production by granulocytes in a concentration-dependent manner. Due to their synergistic effects, it is possible that, in combination with ethanol, they may inhibit O(2)·(-) formation in heavy episodic drinkers.

Anti-radical power gives insight into early lipid oxidation events during frying

NARCIS (Netherlands)

Loon, W.A.M.; Linssen, J.P.H.; Legger, A.; Voragen, A.G.J.

2006-01-01

The aim of this research was to use anti-radical power (ARP) to study early lipid oxidation events during frying. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH¿) test was used to determine the ARP. As oil does not dissolve completely in methanol, which is generally used for the DPPH¿ test, butanol

Enhancing and inhibiting effects of aromatic compounds on luminol-dimethylsulfoxide-OH(-) chemiluminescence and determination of intermediates in oxidative hair dyes by HPLC with chemiluminescence detection.

Science.gov (United States)

Zhou, Jian; Xu, Hong; Wan, Guo-Hui; Duan, Chun-Feng; Cui, Hua

2004-10-08

The effect of 36 aromatic compounds on the luminol-dimethylsulfoxide-OH(-) chemiluminescence (CL) was systematically studied. It was found that dihydroxybenzenes, and ortho- and para-substituted aminophenols and phenylenediamines inhibited the CL and phenols with three or more than three hydroxyls except phloroglucin tended to enhance the CL. The CL inhibition and enhancement was proposed to be dependent on whether superoxide anion radical (O(2)(-)) was competitively consumed by compounds in the CL system. Trihydroxybenzenes were capable of generating superoxide anion radical, leading to the CL enhancement, whereas dihydroxybenzenes were superoxide anion radical scavenger, causing the CL inhibition. Based on the inhibited CL, a novel method for the simultaneous determination of p-phenylenediamine, o-phenylenediamine, p-aminophenol, o-aminophenol, resorcinol and hydroquinone by high-performance liquid chromatography coupled with chemiluminescence detection was developed. The method has been successfully applied to determine intermediates in oxidative hair dyes and wastewater of shampooing after hair dyed.

Evaluation of Antioxidant Properties of Phenolics Extracted from Ananas comosus L.

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Adhikarimayum HARIPYAREE

2010-06-01

Full Text Available Phenolics were extracted from the fruit tissues of Ananas comosus L. var. queen, cv. �Meitei Keehom�, a variety of pineapple grown in Manipur, India, after skin peeling, purified and their antioxidant properties were analyzed. The antioxidant properties were assessed based on the ability of fruit phenolics in absolute methanol to scavenge DPPH, superoxide anion radicals and hydroxyl radicals and compared to antioxidant compounds like ascorbic acid and pyragallol. Pineapple fruit phenolics scavenged DPPH, superioxide anion radicals and hydroxyl radicals in a dose dependent way. In DPPH assay, the IC50 values of pineapple phenolics, ascorbic acid and pyragallol were 12.2?g/ml, 17.82?g/ml and 15.92?g/ml respectively. In superoxide anion and hydroxyl radical scavenging activities, the IC50 values of pineapple phenolics were 11.42?g/ml and 55.292?g/ml, for ascorbic acid 49.62?g/ml, 48.52?g/ml and that of pyragallol was 15.672?g/ml and 60.62?g/ml. The IC50 value was lowest in pineapple phenolics than ascorbic acid and pyragallol in DPPH and superoxide anion assays. But it is higher than ascorbic acid and lower than pyragallol in hydroxyl radical assay. The lower the IC50 values, the higher the antioxidant activities. The phenolics extracted from this variety of pineapple exhibit excellent free radical scavenging activity. The result shows that pineapple and its active constituents may be used in further antioxidative therapy.

Evaluation of Antioxidant Properties of Phenolics Extracted from Ananas comosus L.

Directory of Open Access Journals (Sweden)

Adhikarimayum HARIPYAREE

2010-06-01

Full Text Available Phenolics were extracted from the fruit tissues of Ananas comosus L. var. queen, cv. Meitei Keehom, a variety of pineapple grown in Manipur, India, after skin peeling, purified and their antioxidant properties were analyzed. The antioxidant properties were assessed based on the ability of fruit phenolics in absolute methanol to scavenge DPPH, superoxide anion radicals and hydroxyl radicals and compared to antioxidant compounds like ascorbic acid and pyragallol. Pineapple fruit phenolics scavenged DPPH, superioxide anion radicals and hydroxyl radicals in a dose dependent way. In DPPH assay, the IC50 values of pineapple phenolics, ascorbic acid and pyragallol were 12.2?g/ml, 17.82?g/ml and 15.92?g/ml respectively. In superoxide anion and hydroxyl radical scavenging activities, the IC50 values of pineapple phenolics were 11.42?g/ml and 55.292?g/ml, for ascorbic acid 49.62?g/ml, 48.52?g/ml and that of pyragallol was 15.672?g/ml and 60.62?g/ml. The IC50 value was lowest in pineapple phenolics than ascorbic acid and pyragallol in DPPH and superoxide anion assays. But it is higher than ascorbic acid and lower than pyragallol in hydroxyl radical assay. The lower the IC50 values, the higher the antioxidant activities. The phenolics extracted from this variety of pineapple exhibit excellent free radical scavenging activity. The result shows that pineapple and its active constituents may be used in further antioxidative therapy.

Inhibition of Protein Glycation by Tiger Milk Mushroom [Lignosus rhinocerus (Cooke Ryvarden] and Search for Potential Anti-diabetic Activity-Related Metabolic Pathways by Genomic and Transcriptomic Data Mining

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Hui-Yeng Y. Yap

2018-02-01

Full Text Available Naturally occurring anti-glycation compounds have drawn much interest in recent years as they show potential in reducing or preventing the risk of chronic complications for diabetic patients. In this study, annotation of the genome–transcriptome data from tiger milk mushroom (Lignosus rhinocerus, syn. Lignosus rhinocerotis to PlantCyc enzymes database identified transcripts that are related to anti-diabetic properties, and these include genes that are involved in carotenoid and abscisic acid biosynthesis as well as genes that code for glyoxalase I, catalase-peroxidases, and superoxide dismutases. The existence of these genes suggests that L. rhinocerus may contain bioactive compound(s with anti-glycation properties that can be exploited for management of diabetic complications. A medium-molecular-weight (MMW fraction which was obtained from a combination of cold water extraction and Sephadex® G-50 (fine gel filtration chromatography of L. rhinocerus sclerotia powder was demonstrated to exhibit potent anti-glycation activity. The fraction specifically inhibited the formation of N-(carboxymethyllysine, pentosidine, and other advanced glycation end-product (AGE structures in a human serum albumin-glucose system, with an IC50 value of 0.001 mg/ml, almost 520 times lower than that of the positive control, aminoguanidine hydrochloride (IC50 = 0.52 mg/ml. Its ability to suppress protein glycation may be partly associated with its strong superoxide anion radical scavenging activity (10.16 ± 0.12 mmol TE/g. Our results suggest that the MMW fraction of L. rhinocerus shows potential to be developed into a potent glycation inhibitor for preventing AGE-mediated diabetic complications.

High-performance liquid chromatography coupled with post-column dual-bioactivity assay for simultaneous screening of xanthine oxidase inhibitors and free radical scavengers from complex mixture.

Science.gov (United States)

Li, D Q; Zhao, J; Li, S P

2014-06-06

Xanthine oxidase (XO) can catalyze hypoxanthine and xanthine to generate uric acid and reactive oxygen species (ROS), including superoxide anion radical (O₂(•-)) and hydrogen peroxide. XO inhibitors and free radical scavengers are beneficial to the treatment of gout and many related diseases. In the present study, an on-line high-performance liquid chromatography (HPLC) coupled with post-column dual-bioactivity assay was established and successfully applied to simultaneously screening of XO inhibitors and free radical scavengers from a complex mixture, Oroxylum indicum extract. The integrated system of HPLC separation, bioactivity screening and mass spectrometry identification was proved to be simple and effective for rapid and sensitive screening of individual bioactive compounds in complex mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

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Suvankar Das

2018-01-01

Full Text Available Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH and the anion radical superoxide (·O2−. The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine 10. In general, U251, MCF7, NCI/ADR-RES, NCI-H460 and HT29 cells were least sensitive to the tested compounds and all compounds were considerably more toxic to the studied cancer cell lines than to the normal cell line HaCaT. The binding mode of the compounds and ctDNA was preferably via intercalation. In addition, these results were confirmed based on theoretical studies. Finally, a linear and exponential correlation between interaction constant (Kb and GI50 for several human cancer cell was observed.

Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

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Eldad Saragosti

2010-09-01

Full Text Available Reactive oxygen species (ROS are thought to play a major role in cell death pathways and bleaching in scleractinian corals. Direct measurements of ROS in corals are conspicuously in short supply, partly due to inherent problems with ROS quantification in cellular systems.In this study we characterized the dynamics of the reactive oxygen species superoxide anion radical (O(2(- in the external milieu of the coral Stylophora pistillata. Using a sensitive, rapid and selective chemiluminescence-based technique, we measured extracellular superoxide production and detoxification activity of symbiont (non-bleached and aposymbiont (bleached corals, and of cultured Symbiodinium (from clades A and C. Bleached and non-bleached Stylophora fragments were found to produce superoxide at comparable rates of 10(-11-10(-9 mol O(2(- mg protein(-1 min(-1 in the dark. In the light, a two-fold enhancement in O(2(- production rates was observed in non-bleached corals, but not in bleached corals. Cultured Symbiodinium produced superoxide in the dark at a rate of . Light was found to markedly enhance O(2(- production. The NADPH Oxidase inhibitor Diphenyleneiodonium chloride (DPI strongly inhibited O(2(- production by corals (and more moderately by algae, possibly suggesting an involvement of NADPH Oxidase in the process. An extracellular O(2(- detoxifying activity was found for bleached and non-bleached Stylophora but not for Symbiodinium. The O(2(- detoxifying activity was partially characterized and found to resemble that of the enzyme superoxide dismutase (SOD.The findings of substantial extracellular O(2(- production as well as extracellular O(2(- detoxifying activity may shed light on the chemical interactions between the symbiont and its host and between the coral and its environment. Superoxide production by Symbiodinium possibly implies that algal bearing corals are more susceptible to an internal build-up of O(2(-, which may in turn be linked to oxidative stress

[Cell surface peroxidase--generator of superoxide anion in wheat root cells under wound stress].

Science.gov (United States)

Chasov, A V; Gordon, L Kh; Kolesnikov, O P; Minibaeva, F V

2002-01-01

Development of wound stress in excised wheat roots is known to be accompanied with an increase in reactive oxygen species (ROS) production, fall of membrane potential, release of K+ from cells, alkalization of extracellular solution, changes in respiration and metabolism of structural lipids. Dynamics of superoxide release correlates with changes in other physiological parameters, indicating the cross-reaction of these processes. Activity of peroxidase in extracellular solution after a 1 h incubation and removal of roots was shown to be stimulated by the range of organic acids, detergents, metals, and to be inhibited by cyanide. Superoxide production was sensitive to the addition of Mn2+ and H2O2. Increase in superoxide production correlates with the enhancement of peroxidase activity at the application of organic acids and detergents. The results obtained indicate that cell surface peroxidase is one of the main generators of superoxide in wounded wheat root cells. Different ways of stimulation of the ROS producing activity in root cells is supposed. By controlling superoxide and hydrogen peroxide formation, the cell surface peroxidase can control the adaptation processes in stressed plant cells.

Prevention of alloimmunization by ultraviolet-B irradiation. Inactivation of leukocytes and the generation of active oxygen and radicals

International Nuclear Information System (INIS)

Takahashi, Tsuneo; Mogi, Yuko; Sekiguchi, Sadayoshi; Akasaka, Junichi; Kamo, Naoki; Kuwabara, Mikinori.

1994-01-01

UV-B irradiation of platelet concentrates (PC) has been tried in several institutes to inactivate leukocytes in PC and prevent alloimmunization on platelet transfusion. However, the mechanism of inactivation of leukocytes contaminating PC has not been fully understood. It is known that UV-B light is absorbed by photosensitizers in cells and produces active oxygen and radicals, such as singlet oxygen, superioxide anions and hydroxyl radicals. These active oxygen or radicals should injure cellular components and this could cause the suppression of cellular functions. In this study, we investigated the relationships among UV-B irradiation, free radical generation and leukocyte inactivation. We found the evidence that active oxygen and radicals were produced in peripheral blood mononuclear cells by UV-B irradiation. UV-B irradiation suppressed the stimulatory function of leukocytes in a mixed lymphocyte reaction (MLR), and the suppression depended on the dosage of UV-B. Even a low dosage of UV-B, 10 J/m 2 , could inhibit the MLR if the irradiated cells were incubated at 37degC for 24 hours before co-culture with responder cells. Treatments of cells with the exogenous singlet oxygen or superoxide anions also caused suppression of the stimulatory function in the MLR, inhibition of capping formation of HLA-DR antigens, and an increase of intracellular free Ca 2+ levels as did the UV-B treatment. These results indicate that the active oxygen or radicals generated in UV-B-irradiated leukocytes could be one of the causes of leukocyte inactivation. (author0

Formation and reactivity of free radicals in 5-hydroxymethyl-2-furaldehyde--the effect on isoprenaline photostability.

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Brustugun, Jørgen; Tønnesen, Hanne H; Edge, Ruth; Navaratnam, Suppiah

2005-05-13

Solutions of glucose are used as diluents for drugs in various drug infusions. When sterilized by heat small amounts of the substance 5-hydroxymethyl-2-furaldehyde (5-HMF) is produced from glucose. At a hospital ward such infusions may be exposed to irradiation; including UV-light. The photoreactivity of the furaldehyde is investigated. It is shown to photodestabilize the catecholamine isoprenaline. It is shown to be a producer, but also a consumer, of singlet oxygen. The excited triplet, cation and anion radical have been produced by pulse radiolysis and flash photolysis and their absorbance characteristics have been determined. The triplet absorption spectrum showed absorption bands at 320 and 430 nm with molar absorption coefficients of 4700 and 2600 M-1 cm-1, respectively. The anion radical showed absorption bands at 330 and 420 nm with molar absorption coefficients of 2000 and 300 M-1 cm-1, respectively. The cation radical had an absorption band at 320 nm with a molar absorption coefficient of 5000 M-1 cm-1. The quantum yield for the production of singlet oxygen, sensitized by the 5-HMF triplet, was determined to be 0.6, whilst the quantum yield for the triplet formation was 1.0. Aqueous solutions of 5-HMF were found to photoionize to yield the hydrated electron and the cation radical of 5-HMF in a biphotonic process. The influences of pH, buffer and glucose on the formation of transients were evaluated. The reactions between 5-HMF and the solvated electron, the hydroxyl radical and the superoxide were also studied.

Anti-platelet activity of water dispersible curcuminoids in rat platelets.

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Maheswaraiah, Anikisetty; Rao, Lingamallu Jaganmohan; Naidu, Kamatham Akhilender

2015-03-01

Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10-30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two-fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A2 , serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12-lipoxygenase activity and formation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti-platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders. Copyright © 2015 John Wiley & Sons, Ltd.

In vitro anti-inflammatory and free radical scavenging activities of ...

African Journals Online (AJOL)

Methods: In vitro antioxidant activity was determined using free radical scavenging assays such as DPPH, ABTS and NO2. The antiinflammatory potential was carried out using inhibition of protein denaturation of egg albumin as a model of anti-inflammatory capacity. Results: Both the crude methanolic extract and saponins ...

A multiple free-radical scavenging (MULTIS) study on the antioxidant capacity of a neuroprotective drug, edaravone as compared with uric acid, glutathione, and trolox.

Science.gov (United States)

Kamogawa, Erisa; Sueishi, Yoshimi

2014-03-01

Edaravone (3-methyl-1-phenyl-2-pyrazoline-5-one) is a neuroprotective drug that has been used for brain ischemia injury treatment. Because its activity is speculated to be due to free radical scavenging activity, we carried out a quantitative determination of edaravone's free radical scavenging activity against multiple free radical species. Electron spin resonance (ESR) spin trapping-based multiple free-radical scavenging (MULTIS) method was employed, where target free radicals were hydroxyl radical, superoxide anion, alkoxyl radical, alkylperoxyl radical, methyl radical, and singlet oxygen. Edaravone showed relatively high scavenging abilities against hydroxyl radical (scavenging rate constant k=2.98×10(11) M(-1) s(-1)), singlet oxygen (k=2.75×10(7) M(-1) s(-1)), and methyl radical (k=3.00×10(7) M(-1) s(-1)). Overall, edaravone's scavenging activity against multiple free radical species is as robust as other known potent antioxidant such as uric acid, glutathione, and trolox. A radar chart illustration of the MULTIS activity relative to uric acid, glutathione, and trolox indicates that edaravone has a high and balanced antioxidant activity with low specificity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study of anti-oxidation and scavenging effects on free radicals of quercetin

International Nuclear Information System (INIS)

Wang Chongdao; Qiang Yizhong; Lao Qinhua; Shao Yuan

1999-01-01

The effects of Quercetin on the contents of lipid peroxides (LPO) in the mice caused by γ-whole-body irradiation by method of the modified spectrophotometry of TBA, and the scavenging effects of Quercetin on the free radicals of DNA induced by radiation exposure by means of ESR technique were investigated. The results demonstrates that Quercetin has a good anti-oxidation effect and is very effective in scavenging of free radicals

N-tert-butylmethanimine N-oxide is an efficient spin-trapping probe for EPR analysis of glutathione thiyl radical

Science.gov (United States)

Scott, Melanie J.; Billiar, Timothy R.; Stoyanovsky, Detcho A.

2016-01-01

The electron spin resonance (EPR) spin-trapping technique allows detection of radical species with nanosecond half-lives. This technique is based on the high rates of addition of radicals to nitrones or nitroso compounds (spin traps; STs). The paramagnetic nitroxides (spin-adducts) formed as a result of reactions between STs and radical species are relatively stable compounds whose EPR spectra represent “structural fingerprints” of the parent radical species. Herein we report a novel protocol for the synthesis of N-tert-butylmethanimine N-oxide (EBN), which is the simplest nitrone containing an α-H and a tertiary α′-C atom. We present EPR spin-trapping proof that: (i) EBN is an efficient probe for the analysis of glutathione thiyl radical (GS•); (ii) β-cyclodextrins increase the kinetic stability of the spin-adduct EBN/•SG; and (iii) in aqueous solutions, EBN does not react with superoxide anion radical (O2−•) to form EBN/•OOH to any significant extent. The data presented complement previous studies within the context of synthetic accessibility to EBN and efficient spin-trapping analysis of GS•. PMID:27941944

Aqueous-Phase Reactions of Isoprene with Sulfoxy Radical Anions as a way of Wet Aerosol Formation in the Atmosphere

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Kuznietsova, I.; Rudzinski, K. J.; Szmigielski, R.; Laboratory of the Environmental Chemistry

2011-12-01

Atmospheric aerosols exhibit an important role in the environment. They have implications on human health and life, and - in the larger scale - on climate, the Earth's radiative balance and the cloud's formation. Organic matter makes up a significant fraction of atmospheric aerosols (~35% to ~90%) and may originate from direct emissions (primary organic aerosol, POA) or result from complex physico-chemical processes of volatile organic compounds (secondary organic aerosol, SOA). Isoprene (2-methyl-buta-1,3-diene) is one of the relevant volatile precursor of ambient SOA in the atmosphere. It is the most abundant non-methane hydrocarbon emitted to the atmosphere as a result of living vegetation. According to the recent data, the isoprene emission rate is estimated to be at the level of 500 TgC per year. While heterogeneous transformations of isoprene have been well documented, aqueous-phase reactions of this hydrocarbon with radical species that lead to the production of new class of wet SOA components such as polyols and their sulfate esters (organosulfates), are still poorly recognized. The chain reactions of isoprene with sulfoxy radical-anions (SRA) are one of the recently researched route leading to the formation of organosulfates in the aqueous phase. The letter radical species originate from the auto-oxidation of sulfur dioxide in the aqueous phase and are behind the phenomenon of atmospheric acid rain formation. This is a complicated chain reaction that is catalyzed by transition metal ions, such as manganese(II), iron(III) and propagated by sulfoxy radical anions . The presented work addresses the chemical interaction of isoprene with sulfoxy radical-anions in the water solution in the presence of nitrite ions and nitrous acid, which are important trace components of the atmosphere. We showed that nitrite ions and nitrous acid significantly altered the kinetics of the auto-oxidation of SO2 in the presence of isoprene at different solution acidity from 2 to 8

Effect of metal complexation to anti-inflammatory over the action against oxidative and free radicals: ketoprofen action

International Nuclear Information System (INIS)

Manente, Francine Alessandra; Mello, Lucas Rosolen de Almeida; Vellosa, Jose Carlos Rebuglio; Khalil, Omar Arafat Kdudsi; Carvalho, Claudio Teodoro de; Bannach, Gilbert

2011-01-01

Free radicals are highly reactive species generated in living organisms for the purpose of protection. However, in some circumstances, they are responsible for the occurrence or aggravation of tissue damage. Many anti-inflammatory drugs have a direct effect on free radicals and not radical reactive species, which contributes to its actions against inflammation. Ketoprofen is a nonsteroidal anti-inflammatory agent that generates free radicals by photo irradiation and has an important hemolytic effect with that. The complexation of metals to different drugs has been used as a strategy to improve the pharmacological action of different molecules and reduce their side effects. This paper presents the results of ketoprofen and their metallic complexes action on erythrocytes and free radicals. It was observed that the cerium enhances the scavenger properties of ketoprofen on free radicals, while copper enhances its action over non-radical oxidants. Copper also reduced the hemolytic effect presented by ketoprofen meanwhile its cerium derivative maintained it. (author)

Free radical scavenging potential and HPTLC analysis of Indigofera tinctoria linn (Fabaceae

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Sakthivel Srinivasan

2016-04-01

Full Text Available The objective of this study was to evaluate the free radical scavenging potential and high performance thin layer chromatography (HPTLC fingerprinting of Indigofera tinctoria (I. tinctoria. Phytochemical analysis was carried out using standard methods, and free radical scavenging activity of the plant was determined using 2,2-diphenyl-1-picrylhydrazy (DPPH, nitric oxide (NO and superoxide anion (O2− radical scavenging capacities. HPTLC plate was kept in CAMAG TLC Scanner 3 and the Rf values at fingerprint data were recorded by WINCATS software. Aqueous extract of I. tinctoria reliably showed the total phenolics (267.2±2.42 mg/g, flavonoids (75.43±3.36 mg/g and antioxidants (349.11±8.04 mg/g. The extract was found to have DPPH (52.08%, NO (23.12% and O2− (26.79% scavenging activities at the concentration of 250 μg/mL and the results were statistically significant compared with ascorbic acid standard (p<0.05. HPTLC results confirmed that the extract contained several potential active components such as phenols, flavonoids, saponins and terpenoids as the slides revealed multi-colored bands of varying intensities. This study confirmed that the plant had multipotential antioxidant and free radicals scavenging activities.

Antioxidative Flavonol Glucuronides and Anti-HBsAg Flavonol from Rotala rotundifolia

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Li-Jie Zhang

2011-10-01

Full Text Available Two new flavonol glucuronides, quercetin 3-O-β-d-2″-acetylglucuronide (1 and quercetin 3-O-β-d-2″-acetylglucuronide methyl ester (2, along with four known flavonoids (3-6 were isolated from the whole parts of Rotala rotundifolia. The structures of 1 and 2 were elucidated by application of various spectroscopic methods, including 1D and 2D NMR techniques. Biological evaluation showed that all of isolated flavonoid compounds have potent anti-oxidative activities by DPPH and superoxide anion methods, and kaempferol (3 and quercetin (4 exhibited significant anti-HBV activity assayed by anti-HBsAg production. The HPLC fingerprint with photodiode array detection (HPLC-DAD for quality control of R. rotundifolia partitioned EtOAc layer was also established.

Free radical reactions of isoxazole and pyrazole derivatives of hispolon: kinetics correlated with molecular descriptors.

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Shaikh, Shaukat Ali M; Barik, Atanu; Singh, Beena G; Modukuri, Ramani V; Balaji, Neduri V; Subbaraju, Gottumukkala V; Naik, Devidas B; Priyadarsini, K Indira

2016-12-01

Hispolon (HS), a natural polyphenol found in medicinal mushrooms, and its isoxazole (HI) and pyrazole (HP) derivatives have been examined for free radical reactions and in vitro antioxidant activity. Reaction of these compounds with one-electron oxidant, azide radicals ([Formula: see text]) and trichloromethyl peroxyl radicals ([Formula: see text]), model peroxyl radicals, studied by nanosecond pulse radiolysis technique, indicated formation of phenoxyl radicals absorbing at 420 nm with half life of few hundred microseconds (μs). The formation of phenoxyl radicals confirmed that the phenolic OH is the active centre for free radical reactions. Rate constant for the reaction of these radicals with these compounds were in the order k HI ≅ k HP  >   k HS . Further the compounds were examined for their ability to inhibit lipid peroxidation in model membranes and also for the scavenging of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide ([Formula: see text]) radicals. The results suggested that HP and HI are less efficient than HS towards these radical reactions. Quantum chemical calculations were performed on these compounds to understand the mechanism of reaction with different radicals. Lower values of adiabatic ionization potential (AIP) and elevated highest occupied molecular orbital (HOMO) for HI and HP compared with HS controlled their activity towards [Formula: see text] and [Formula: see text] radicals, whereas the contribution of overall anion concentration was responsible for higher activity of HS for DPPH, [Formula: see text], and lipid peroxyl radical. The results confirm the role of different structural moieties on the antioxidant activity of hispolon derivatives.

Mitochondrial Protection and Anti-aging Activity of Astragalus Polysaccharides and Their Potential Mechanism

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Xiao-Juan Xin

2012-02-01

Full Text Available The current study was performed to investigate mitochondrial protection and anti-aging activity of Astragalus polysaccharides (APS and the potential underlying mechanism. Lipid peroxidation of liver and brain mitochondria was induced by Fe2+–Vit C in vitro. Thiobarbituric acid (TBA colorimetry was used to measure the content of thiobarbituric acid reactive substances (TBARS. Mouse liver mitochondrial permeability transition (PT was induced by calcium overload in vitro and spectrophotometry was used to measure it. The scavenging activities of APS on superoxide anion (O2•－ and hydroxyl radical (•OH, which were produced by reduced nicotinamide adenine dinucleotide (NADH—N-Methylphenazonium methyl sulfate (PMS and hydrogen peroxide (H2O2–Fe2+ system respectively, were measured by 4-nitrobluetetrazolium chloride (NBT reduction and Fenton reaction colorimetry respectively. The Na2S2O3 titration method was used to measure the scavenging activities of APS on H2O2. APS could inhibit TBARS production, protect mitochondria from PT, and scavenge O2•－, •OH and H2O2 significantly in a concentration-dependent manner respectively. The back of the neck of mice was injected subcutaneously with D-galactose to induce aging at a dose of 100 mg/kg/d for seven weeks. Moreover, the activities of catalase (CAT, surperoxide dismutase (SOD and glutathione peroxidase (GPx and anti-hydroxyl radical which were assayed by using commercial monitoring kits were increased significantly in vivo by APS. According to this research, APS protects mitochondria by scavenging reactive oxygen species (ROS, inhibiting mitochondrial PT and increasing the activities of antioxidases. Therefore, APS has the effect of promoting health.

Anti-HIV and immunomodulation activities of cacao mass lignin-carbohydrate complex.

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Sakagami, Hiroshi; Kawano, Michiyo; Thet, May Maw; Hashimoto, Ken; Satoh, Kazue; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Haishima, Yuji; Maeda, Yuuichi; Sakurai, Koji

2011-01-01

Recently, a prominent antiviral and macrophage stimulatory activity of cacao lignin-carbohydrate complex (LCC) has been reported. However, the solubility and sterility of LCC have not been considered yet. In the present study, complete solubilisation and sterilisation was achieved by autoclaving under mild alkaline conditions and the previously reported biological activities were re-examined. LCCs were obtained by 1% NaOH extraction and acid precipitation, and a repeated extraction-precipitation cycle. Nitric oxide (NO) and cytokine productions were assayed by the Griess method and ELISA, respectively. Inducible NO synthase (iNOS) expression was determined by Western blot analysis. Superoxide anion, hydroxyl radical and nitric oxide radical-scavenging activity was determined by ESR spectroscopy. Cacao mass LCC showed reproducibly higher anti-HIV activity than cacao husk LCC. Cacao mass LCC, up to 62.5 μg/ml, did not stimulate mouse macrophage-like cells (RAW264.7 and J774.1) to produce NO, nor did it induce iNOS protein, in contrast to lipopolysaccharide (LPS). Cacao mass LCC and LPS synergistically stimulated iNOS protein expression, suggesting a different point of action. Cacao mass LCC induced tumour necrosis factor-α production markedly less than LPS, and did not induce interleukin-1β, interferon-α or interferon-γ. ESR spectroscopy showed that cacao mass LCC, but not LPS, scavenged NO produced from NOC-7. This study demonstrated several new biological activities of LCCs distinct from LPS and further confirmed the promising antiviral and immunomodulating activities of LCCs.

Glutarimide alkaloids and a terpenoid benzoquinone from Cordia globifera.

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Parks, Joshua; Gyeltshen, Thinley; Prachyawarakorn, Vilailak; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

2010-05-28

Three new compounds, a meroterpene (2) having a cyclopropane moiety named globiferane and glutarimide alkaloids named cordiarimides A (3) and B (4), were isolated from the roots of Cordia globifera. Compounds 2-4 exhibited weak cytotoxic activity. Cordiarimide B (4) exhibited radical scavenging activity, as it inhibited superoxide anion radical formation in the xanthine/xanthine oxidase (XXO) assay, and also suppressed superoxide anion generation in differentiated HL-60 human promyelocytic leukemia cells when induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). This is the first report on the presence of glutarimide alkaloids in the genus Cordia.

Titanium dioxide nanoparticles enhance production of superoxide anion and alter the antioxidant system in human osteoblast cells

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Niska K

2015-02-01

Full Text Available Karolina Niska,1 Katarzyna Pyszka,1 Cecylia Tukaj,2 Michal Wozniak,1 Marek Witold Radomski,3–5 Iwona Inkielewicz-Stepniak1 1Department of Medical Chemistry, 2Department of Electron Microscopy, Medical University of Gdansk, Gdansk, Poland; 3School of Pharmacy and Pharmaceutical Sciences, Trinity Biomedical Sciences Institute, The University of Dublin Trinity College, Dublin, Ireland; 4Kardio-Med Silesia, 5Silesian Medical University, Zabrze, Poland Abstract: Titanium dioxide (TiO2 nanoparticles (NPs are manufactured worldwide for a variety of engineering and bioengineering applications. TiO2NPs are frequently used as a material for orthopedic implants. However, to the best of our knowledge, the biocompatibility of TiO2NPs and their effects on osteoblast cells, which are responsible for the growth and remodeling of the human skeleton, have not been thoroughly investigated. In the research reported here, we studied the effects of exposing hFOB 1.19 human osteoblast cells to TiO2NPs (5–15 nm for 24 and 48 hours. Cell viability, alkaline phosphatase (ALP activity, cellular uptake of NPs, cell morphology, superoxide anion (O2•- generation, superoxide dismutase (SOD activity and protein level, sirtuin 3 (SIR3 protein level, correlation between manganese (Mn SOD and SIR, total antioxidant capacity, and malondialdehyde were measured following exposure of hFOB 1.19 cells to TiO2NPs. Exposure of hFOB 1.19 cells to TiO2NPs resulted in: (1 cellular uptake of NPs; (2 increased cytotoxicity and cell death in a time- and concentration-dependent manner; (3 ultrastructure changes; (4 decreased SOD and ALP activity; (5 decreased protein levels of SOD1, SOD2, and SIR3; (6 decreased total antioxidant capacity; (7 increased O2•- generation; and (8 enhanced lipid peroxidation (malondialdehyde level. The linear relationship between the protein level of MnSOD and SIR3 and between O2•- content and SIR3 protein level was observed. Importantly, the cytotoxic

Reaction of hypotaurine or taurine with superoxide produces the organic peroxysulfonic acid peroxytaurine.

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Grove, Roxanna Q; Karpowicz, Steven J

2017-07-01

Hypotaurine and taurine are amino acid derivatives and abundant molecules in many eukaryotes. The biological reaction in which hypotaurine is converted to taurine remains poorly understood. Here, hypotaurine and taurine were observed to react with superoxide anion in vitro to form the novel molecule peroxytaurine. In contrast, hypotaurine reacts with hydrogen peroxide to form taurine, but taurine does not react with hydrogen peroxide in vitro. Mass and NMR spectrometry as well as FTIR and Raman spectroscopy support the molecular characterization of peroxytaurine. Gravitometric and spectroscopy experiments suggest a stoichiometry of two superoxide anions reacting with one hypotaurine or two taurines. The newly identified molecule is a semi-stable, organic peroxysulfonic acid that may be an intermediate metabolite in taurine synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Structural damage to lymphocyte nuclei by H2O2 or gamma irradiation is dependent on the mechanism of OH anion radical production

International Nuclear Information System (INIS)

Allan, I.M.; Vaughan, A.T.M.; Milner, A.E.; Lunec, J.; Bacon, P.A.

1988-01-01

Normal human lymphocytes were exposed to OH anion radicals produced indirectly by exposure to H 2 O 2 or directly by gamma irradiation. Using a flow cytometry technique to measure changes in nucleoid size, it was found that generation of OH anion in each system produced a characteristic relaxation in nuclear supercoiling. Exposure of cells to H 2 O 2 produced a metal-dependent step-wise relaxation in extracted nucleoids, while gamma irradiation induced a gradual dose-dependent increase in nucleoid size. The site-specific metal-dependent changes produced in lymphocytes incubated in H 2 O 2 should also occur in gamma irradiated cells, but the characteristic effects on nuclear supercoiling would not be detected within the background of random DNA damage. The importance of metals in maintaining the supercoiled loop configuration of DNA within the protein matrix suggests that free radical damage at metal locations may be particularly toxic for the cell. (author)

Oxidative stress and enzymatic scavenging of superoxide radicals induced by solar UV-B radiation in Ulva canopies from southern Spain

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Kai Bischof

2003-09-01

Full Text Available The generation of reactive oxygen species (ROS and scavenging of the superoxide radical by superoxide dismutase (SOD was studied in mat-like canopies of the green macroalga Ulva rotundata Bliding in a tidal brine pond system in southern Spain. Artificial canopies were covered with different cut-off filters, generating different radiation conditions. ROS and SOD were assessed after three days of exposure. ROS induced lipid peroxidation depended on the position of individual thalli within the canopy and on radiation conditions. Samples exposed to the full solar spectrum were most affected, whereas samples either exposed to photosynthetically active radiation (PAR alone or UV radiation without PAR exhibited fewer peroxidation products. The activity of SOD appeared to be controlled by the impinging UV-A and UV-B radiation and also increased in response to oxidative stress. The results provide evidence for additive effects of high PAR and UV-B under field conditions and support the previously proposed hypothesis that UV-B effects are mediated by an inhibition of the xanthophyll cycle, which increases ROS production and, consequently, causes oxidative damage to components of the photosynthetic machinery, such as proteins and pigments.

Antioxidant potential of Aesculus hippocastanum extract and escin against reactive oxygen and nitrogen species.

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Vašková, J; Fejerčáková, A; Mojžišová, G; Vaško, L; Patlevič, P

2015-01-01

Antioxidant, anti-inflammatory and venoconstrictor properties have been attributed to extracts from Aesculus hippocastanum. These unusual and diverse properties may be possibly basically linked with ability to scavenge free radicals. The scavenging capacity of dry horse chestnut extract of and escin have been investigated in vitro against superoxide anion radicals, hydroxyl radicals, nitrites and peroxynitrite. In general, the activity of the whole extract against superoxide radicals did not exceed 15% at pH 7.4, but the highest inhibition (46.11%) was recorded against hydroxyl radicals at a concentration of 100 µg.ml-1; however, the activity against other radicals was lower. Escin demonstrated a better ability to counteract nitric oxide oxidation products, nitrites. However, the efficiency of the whole extract completely disappeared as the concentration increased. Both extracts showed very low activity towards peroxynitrite. Escin was even able to induce peroxynitrite formation at the lower concentrations used. Whole extract showed better antiradical properties compared to its main active ingredient, escin, probably due to potential synergistic interaction with a mixture of compounds present in the plant extract. These findings can be the basis of both the presentation of side-effects and the persistence of disease in spite of ongoing treatment.

Ursolic acid inhibits superoxide production in activated neutrophils and attenuates trauma-hemorrhage shock-induced organ injury in rats.

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Tsong-Long Hwang

Full Text Available Neutrophil activation is associated with the development of organ injury after trauma-hemorrhagic shock. In the present study, ursolic acid inhibited the superoxide anion generation and elastase release in human neutrophils. Administration of ursolic acid attenuated trauma-hemorrhagic shock-induced hepatic and lung injuries in rats. In addition, administration of ursolic acid attenuated the hepatic malondialdehyde levels and reduced the plasma aspartate aminotransferase and alanine aminotransferase levels after trauma-hemorrhagic shock. In conclusion, ursolic acid, a bioactive natural compound, inhibits superoxide anion generation and elastase release in human neutrophils and ameliorates trauma-hemorrhagic shock-induced organ injury in rats.

Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation.

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Aiken, Kimberly J; Bickford, Justin S; Kilberg, Michael S; Nick, Harry S

2008-04-18

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging.

Extraction of Erythrocyte Enzymes for the Preparation of Polyhemoglobin-catalase-superoxide Dismutase

OpenAIRE

Gu, Jingsong; Chang, Thomas Ming Swi

2009-01-01

In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study ...

Identification of mitochondrial electron transport chain-mediated NADH radical formation by EPR spin-trapping techniques.

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Matsuzaki, Satoshi; Kotake, Yashige; Humphries, Kenneth M

2011-12-20

The mitochondrial electron transport chain (ETC) is a major source of free radical production. However, due to the highly reactive nature of radical species and their short lifetimes, accurate detection and identification of these molecules in biological systems is challenging. The aim of this investigation was to determine the free radical species produced from the mitochondrial ETC by utilizing EPR spin-trapping techniques and the recently commercialized spin-trap, 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO). We demonstrate that this spin-trap has the preferential quality of having minimal mitochondrial toxicity at concentrations required for radical detection. In rat heart mitochondria and submitochondrial particles supplied with NADH, the major species detected under physiological pH was a carbon-centered radical adduct, indicated by markedly large hyperfine coupling constant with hydrogen (a(H) > 2.0 mT). In the presence of the ETC inhibitors, the carbon-centered radical formation was increased and exhibited NADH concentration dependency. The same carbon-centered radical could also be produced with the NAD biosynthesis precursor, nicotinamide mononucleotide, in the presence of a catalytic amount of NADH. The results support the conclusion that the observed species is a complex I derived NADH radical. The formation of the NADH radical could be blocked by hydroxyl radical scavengers but not SOD. In vitro experiments confirmed that an NADH-radical is readily formed by hydroxyl radical but not superoxide anion, further implicating hydroxyl radical as an upstream mediator of NADH radical production. These findings demonstrate the identification of a novel mitochondrial radical species with potential physiological significance and highlight the diverse mechanisms and sites of production within the ETC.

Implications of chronic daily anti-oxidant administration on the inflammatory response to intracortical microelectrodes

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Potter-Baker, Kelsey A.; Stewart, Wade G.; Tomaszewski, William H.; Wong, Chun T.; Meador, William D.; Ziats, Nicholas P.; Capadona, Jeffrey R.

2015-08-01

Objective. Oxidative stress events have been implicated to occur and facilitate multiple failure modes of intracortical microelectrodes. The goal of the present study was to evaluate the ability of a sustained concentration of an anti-oxidant and to reduce oxidative stress-mediated neurodegeneration for the application of intracortical microelectrodes. Approach. Non-functional microelectrodes were implanted into the cortex of male Sprague Dawley rats for up to sixteen weeks. Half of the animals received a daily intraperitoneal injection of the natural anti-oxidant resveratrol, at 30 mg kg-1. The study was designed to investigate the biodistribution of the resveratrol, and the effects on neuroinflammation/neuroprotection following device implantation. Main results. Daily maintenance of a sustained range of resveratrol throughout the implantation period resulted in fewer degenerating neurons in comparison to control animals at both two and sixteen weeks post implantation. Initial and chronic improvements in neuronal viability in resveratrol-dosed animals were correlated with significant reductions in local superoxide anion accumulation around the implanted device at two weeks after implantation. Controls, receiving only saline injections, were also found to have reduced amounts of accumulated superoxide anion locally and less neurodegeneration than controls at sixteen weeks post-implantation. Despite observed benefits, thread-like adhesions were found between the liver and diaphragm in resveratrol-dosed animals. Significance. Overall, our chronic daily anti-oxidant dosing scheme resulted in improvements in neuronal viability surrounding implanted microelectrodes, which could result in improved device performance. However, due to the discovery of thread-like adhesions, further work is still required to optimize a chronic anti-oxidant dosing regime for the application of intracortical microelectrodes.

Attenuation of 6-hydroxydopamine-induced dopaminergic nigrostriatal lesions in superoxide dismutase transgenic mice

International Nuclear Information System (INIS)

Cadet, J.L.; Hirata, H.; Asanuma, M.

1998-01-01

6-Hydroxydopamine is a neurotoxin that produces degeneration of the nigrostriatal dopaminergic pathway in rodents. Its toxicity is thought to involve the generation of superoxide anion secondary to its autoxidation. To examine the effects of the overexpression of Cu,Zn-superoxide dismutase activity on 6-hydroxydopamine-induced dopaminergic neuronal damage, we have measured the effects of 6-hydroxydopamine on striatal and nigral dopamine transporters and nigral tyrosine hydroxylase-immunoreactive neurons in Cu,Zn-superoxide dismutase transgenic mice. Intracerebroventricular injection of 6-hydroxydopamine (50 μg) in non-transgenic mice produced reductions in the size of striatal area and an enlargement of the cerebral ventricle on both sides of the brains of mice killed two weeks after the injection. In addition, 6-hydroxydopamine caused marked decreases in striatal and nigral [ 125 I]RTI-121-labelled dopamine transporters not only on the injected side but also on the non-injected side of non-transgenic mice; this was associated with decreased cell number and size of tyrosine hydroxylase-immunoreactive dopamine neurons in the substantia nigra pars compacta on both sides in these mice. In contrast, superoxide dismutase transgenic mice were protected against these neurotoxic effects of 6-hydroxydopamine, with the homozygous transgenic mice showing almost complete protection.These results provide further support for a role of superoxide anion in the toxic effects of 6-hydroxydopamine. They also provide further evidence that reactive oxygen species may be the main determining factors in the neurodegenerative effects of catecholamines. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

SUPEROXIDE-DEPENDENT IRON UPTAKE: A NEW ROLE FOR ANION EXCHANGE PROTEIN 2

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Lung cells import iron across the plasma membrane as ferrous (Fe2+) ion by incompletely understood mechanisms. We tested the hypothesis that human bronchial epithelial (HBE) cells import non-transferrin-bound iron (NTBI) using superoxide-dependent ferri-reductase activity involvi...

Anti-inflammatory and anti-oxidant properties of Sida rhombifolia stems and roots in adjuvant induced arthritic rats.

Science.gov (United States)

Narendhirakannan, R T; Limmy, T P

2012-04-01

Free radical stress leads to tissue injury and progression of disease conditions such as arthritis, hemorrhagic shock, atherosclerosis, diabetes, hepatic injury, aging and ischemia, reperfusion injury of many tissues, gastritis, tumor promotion, neurodegenerative diseases and carcinogenesis. Safer anti-oxidants suitable for long term use are needed to prevent or stop the progression of free radical mediated disorders. Herbal medicine provides a foundation for various traditional medicine systems worldwide. The Sida species is one of the most important families of medicinal plants in India. Hence, the present study was aimed to investigate the possible anti-oxidant potential of Sida rhombifolia extracts for 30 days on adjuvant induced arthritis in experimental rats. The altered levels of hematological parameters were reverted to near normal levels, especially the elevated rate of erythrocyte sedimentation was significantly reduced by S. rhombifolia extracts in experimental rats. Oral administration of root and stem of S. rhombifolia extracts significantly increased the levels of thiobarbituric acid reactive substances and activities of catalase and glutathione peroxidase and decreased the levels of reduced glutathione and superoxide dismutase activity in arthritis induced rats. The free radical scavenging activity of the plant was further evidenced by histological and transmission electron microscopy observations made on the hind limb tissue.

Titanium dioxide nanoparticles enhance production of superoxide anion and alter the antioxidant system in human osteoblast cells

Science.gov (United States)

Niska, Karolina; Pyszka, Katarzyna; Tukaj, Cecylia; Wozniak, Michal; Radomski, Marek Witold; Inkielewicz-Stepniak, Iwona

2015-01-01

Titanium dioxide (TiO2) nanoparticles (NPs) are manufactured worldwide for a variety of engineering and bioengineering applications. TiO2NPs are frequently used as a material for orthopedic implants. However, to the best of our knowledge, the biocompatibility of TiO2NPs and their effects on osteoblast cells, which are responsible for the growth and remodeling of the human skeleton, have not been thoroughly investigated. In the research reported here, we studied the effects of exposing hFOB 1.19 human osteoblast cells to TiO2NPs (5–15 nm) for 24 and 48 hours. Cell viability, alkaline phosphatase (ALP) activity, cellular uptake of NPs, cell morphology, superoxide anion (O2•−2) generation, superoxide dismutase (SOD) activity and protein level, sirtuin 3 (SIR3) protein level, correlation between manganese (Mn) SOD and SIR, total antioxidant capacity, and malondialdehyde were measured following exposure of hFOB 1.19 cells to TiO2NPs. Exposure of hFOB 1.19 cells to TiO2NPs resulted in: (1) cellular uptake of NPs; (2) increased cytotoxicity and cell death in a time- and concentration-dependent manner; (3) ultrastructure changes; (4) decreased SOD and ALP activity; (5) decreased protein levels of SOD1, SOD2, and SIR3; (6) decreased total antioxidant capacity; (7) increased O2•− generation; and (8) enhanced lipid peroxidation (malondialdehyde level). The linear relationship between the protein level of MnSOD and SIR3 and between O2•− content and SIR3 protein level was observed. Importantly, the cytotoxic effects of TiO2NPs were attenuated by the pretreatment of hFOB 1.19 cells with SOD, indicating the significant role of O2•− in the cell damage and death observed. Thus, decreased expression of SOD leading to increased oxidizing stress may underlie the nanotoxic effects of TiO2NPs on human osteoblasts. PMID:25709434

Free Radicals and Extrinsic Skin Aging

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Borut Poljšak

2012-01-01

Full Text Available Human skin is constantly directly exposed to the air, solar radiation, environmental pollutants, or other mechanical and chemical insults, which are capable of inducing the generation of free radicals as well as reactive oxygen species (ROS of our own metabolism. Extrinsic skin damage develops due to several factors: ionizing radiation, severe physical and psychological stress, alcohol intake, poor nutrition, overeating, environmental pollution, and exposure to UV radiation (UVR. It is estimated that among all these environmental factors, UVR contributes up to 80%. UV-induced generation of ROS in the skin develops oxidative stress, when their formation exceeds the antioxidant defence ability of the target cell. The primary mechanism by which UVR initiates molecular responses in human skin is via photochemical generation of ROS mainly formation of superoxide anion (O2−•, hydrogen peroxide (H2O2, hydroxyl radical (OH•, and singlet oxygen (1O2. The only protection of our skin is in its endogenous protection (melanin and enzymatic antioxidants and antioxidants we consume from the food (vitamin A, C, E, etc.. The most important strategy to reduce the risk of sun UVR damage is to avoid the sun exposure and the use of sunscreens. The next step is the use of exogenous antioxidants orally or by topical application and interventions in preventing oxidative stress and in enhanced DNA repair.

EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines.

Science.gov (United States)

Dikalov, Sergey I; Kirilyuk, Igor A; Voinov, Maxim; Grigor'ev, Igor A

2011-04-01

Superoxide (O₂ⁱ⁻) has been implicated in the pathogenesis of many human diseases, but detection of the O(2)(•-) radicals in biological systems is limited due to inefficiency of O₂ⁱ⁻ spin trapping and lack of site-specific information. This work studied production of extracellular, intracellular and mitochondrial O₂ⁱ⁻ in neutrophils, cultured endothelial cells and isolated mitochondria using a new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O₂ⁱ⁻, producing stable nitroxides and allowing site-specific cO₂ⁱ⁻ detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O₂ⁱ⁻. Inhibition of EPR signal by SOD2 over-expression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O₂ⁱ⁻ both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected an increase in cytoplasm O₂ⁱ⁻ stimulated by PMA, but only CM-H and mitoTEMPO-H showed an increase in rotenone-induced mitochondrial O₂ⁱ⁻. These data show that a new set of hydroxylamine spin probes provide unique information about site-specific production of the O₂ⁱ⁻ radical in extracellular or intracellular compartments, cytoplasm or mitochondria.

Depletion Of The Protective Aluminum Hydroxide Coating In TiO2-Based Sunscreens By Swimming Pool Water Ingredients

Science.gov (United States)

In sunscreen lotion (SSL) formulations, titanium dioxide (nTiO2) nanoparticles are coated with an Al(OH)3 layer to shield against the harmful effects of hydroxyl radicals (•OH), superoxide anion radicals (O2-•), and other reactive oxyge...

Chemistry of superoxide radical in seawater: CDOM associated sink of superoxide in coastal waters

Energy Technology Data Exchange (ETDEWEB)

Goldstone, J.V.; Voelker, B.M.

2000-03-15

Colored dissolved organic matter (CDOM) and humic substances contain a nonmetallic redox-cycling component capable of catalyzing superoxide (O{sub 2}{sup {minus}}) dismutation. First-order rate coefficients (k{sub pseudo}) measured for this O{sub 2}{sup {minus}} sink in a number of coastal and Chesapeake Bay water samples range up to 1.4s{sup {minus}1}, comparable in magnitude to catalyzed dismutation by Cu species. A significant (r{sup 2}=0.73) correlation is observed between k{sub pseudo} and the optical absorption and salinity of individual coastal water samples, suggesting an association with non-marine-derived CDOM. The activity of this sink is not changed by acidification or boiling of samples but is removed by photooxidation, indicating that it is an organic compound, but that it is neither enzymatic nor likely to consist of tightly bound metals. The stoichiometry of hydrogen peroxide formation from O{sub 2}{sup {minus}} decay indicates that this sink is capable of a redox cycle catalyzing the dismutation of O{sub 2}{sup {minus}}. This CDOM sink combined with the organic copper sink previously described will produce a steady-state superoxide concentration in coastal waters that is 100--1000-fold lower than that predicted from bimolecular dismutation alone. Catalyzed O{sub 2}{sup {minus}} decay was also observed in a variety of humic and fulvic acid samples, possibly occurring through quinone functionalities. Although the presence of quinone moieties in humic and fulvic acids has been demonstrated, there do not appear to be good correlations between several measures of quinone content and the O{sub 2}{sup {minus}} dismutation rates of these samples.

A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

International Nuclear Information System (INIS)

McAdam, M.E.; Lavelle, F.; Fox, R.A.; Fielden, E.M.

1977-01-01

The mechanism of catalysis of the manganese-containing superoxide dismutase from Bacillus stearothermophilus has been shown to involve a 'fast cycle' and a 'slow cycle' (McAdam, M.E., Fox, R.A., Lavelle, F., and Fielden, E.M., Biochem. J.; 165:71 (1977)). Further properties of the enzyme are now considered. Pulse-radiolysis studies, under conditions of low substrate concentration to enzyme concentration (i.e. when the fast cycle predominates), showed that enzyme activity decreases as pH increases (6.5 to 10.2). Activity was unaffected by the addition of H 2 O 2 or NaN 3 but slightly decreased by KCN. Both H 2 O 2 and the reducing radical anion CO 2 sup(-.) caused a decrease in A 480 of the native enzyme. The rate of the fast catalytic cycle was independent of temperature (5 to 55 0 C), and as temperature increased the slow catalytic cycle became relatively more important. Arrhenius parameters of the rate constants were estimated. The possible identity of the various forms of the enzyme is considered. (author)

An EPR spin-probe and spin-trap study of the free radicals produced by plant plasma membranes

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GORAN BACIC

2005-02-01

Full Text Available Plant plasma membranes are known to produce superoxide radicals, while the production of hydroxyl radical is thought to occur only in the cell wall. In this work it was demonstrated using combined spin-trap and spin-probe EPR spectroscopic techniques, that plant plasma membranes do produce superoxide and hydroxyl radicals but by kinetically different mechanisms. The results show that superoxide and hydroxyl radicals can be detected by DMPO spin-trap and that the mechanisms and location of their production can be differentiated using the reduction of spin-probes Tempone and 7-DS. It was shown that the mechanism of production of oxygen reactive species is NADH dependent and diphenylene iodonium inhibited. The kinetics of the reduction of Tempone, combined with scavengers or the absence of NADH indicates that hydroxyl radicals are produced by a mechanism independent of that of superoxide production. It was shown that a combination of the spin-probe and spin-trap technique can be used in free radical studies of biological systems, with a number of advantages inherent to them.

Metabolic Regulation of Manganese Superoxide Dismutase Expression via Essential Amino Acid Deprivation*

Science.gov (United States)

Aiken, Kimberly J.; Bickford, Justin S.; Kilberg, Michael S.; Nick, Harry S.

2008-01-01

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging. PMID:18187411

[Resistance of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ to reactive oxygen species].

Science.gov (United States)

Zhang, Shuwen; Lv, Jiaping; Menghe, Bilige; Zhang, Heping; Zhang, Liyu; Song, Jinhui; Wang, Zhifei

2009-02-01

We evaluated antioxidative effect of two antioxidative strains, isolated from the traditional fermented dairy products. Both intact cells and cell-free extract of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ were used to study the inhibited effect of linoleic acid peroxidation, the ability of scavenging 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide anion radical,the ability of tolerancing hydrogen peroxide and the chelating capacity of ferrous ion and reducting activity. Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ demonstrated highest inhibition on linoleic acid peroxidation by 62.95% and 66.16%, respectively. The cell-free extract showed excellent scavenging superoxide anion and hydroxyl radicals activity. However, the intact cells of Lactobacillus delbrueckii subsp. bulgaricus LJJ scavenging superoxide and hydroxyl radicals capacity were not detected. The intact cells of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ on 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability and chelating ferrous ion capacity were superior to cell-free extract. The highest reduced activety was equivalent to 305 micromol/L and 294 micromol/L L-cysteine. Two latobacilli strains had good antioxidant capacity. As potential probiotics, it can be used in future.

Multiple free-radical scavenging capacity in serum

Science.gov (United States)

Oowada, Shigeru; Endo, Nobuyuki; Kameya, Hiromi; Shimmei, Masashi; Kotake, Yashige

2012-01-01

We have developed a method to determine serum scavenging-capacity profile against multiple free radical species, namely hydroxyl radical, superoxide radical, alkoxyl radical, alkylperoxyl radical, alkyl radical, and singlet oxygen. This method was applied to a cohort of chronic kidney disease patients. Each free radical species was produced with a common experimental procedure; i.e., uv/visible-light photolysis of free-radical precursor/sensitizer. The decrease in free-radical concentration by the presence of serum was quantified with electron spin resonance spin trapping method, from which the scavenging capacity was calculated. There was a significant capacity change in the disease group (n = 45) as compared with the healthy control group (n = 30). The percent values of disease’s scavenging capacity with respect to control group indicated statistically significant differences in all free-radical species except alkylperoxyl radical, i.e., hydroxyl radical, 73 ± 12% (p = 0.001); superoxide radical, 158 ± 50% (p = 0.001); alkoxyl radical, 121 ± 30% (p = 0.005); alkylperoxyl radical, 123 ± 32% (p>0.1); alkyl radical, 26 ± 14% (p = 0.001); and singlet oxygen, 57 ± 18% (p = 0.001). The scavenging capacity profile was illustrated using a radar chart, clearly demonstrating the characteristic change in the disease group. Although the cause of the scavenging capacity change by the disease state is not completely understood, the profile of multiple radical scavenging capacities may become a useful diagnostic tool. PMID:22962529

Effects of superoxide dismutase, dithiothreitol and formate ion on the inactivation of papain by hydroxyl and superoxide radicals in aerated solutions

International Nuclear Information System (INIS)

Lin, W.S.; Armstrong, D.A.

1978-01-01

Losses in enzyme activity and sulphydryl content have been studied in aerated papain solutions containing formate, superoxide dismutase and dithiothreitol. Both formate and dithiothreitol converted .OH to .0 2 -, whereas superoxide dismutase completely suppressed the inactivation by .0 2 -. Using results from all systems, the fraction of .0 2 - reactions with papain that caused inactivation of the enzyme was 0.33+-0.07. The results also showed that the fraction of .OH reactions, which cause inactivation of papain, is significantly higher in aerated than in oxygen-free solutions. (author)

A case for hidden b anti b tetraquarks based on e{sup +}e{sup -} {yields} b anti b cross sections between {radical}(s) = 10.54 and 11.20 GeV

Energy Technology Data Exchange (ETDEWEB)

Ali, Ahmed; Hambrock, Christian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ahmed, Ishtiaq [Quaid-i-Azam Univ., Islamabad (Pakistan). National Centre for Physics; Aslam, M. Jamil [Quaid-i-Azam Univ., Islamabad (Pakistan). Physics Dept.

2009-11-15

We study the spectroscopy and dominant decays of the bottomonium-like tetraquarks (bound diquarks-antidiquarks), focusing on the lowest lying P-wave [bq][anti b anti q] states Y{sub [bq]} (with q=u,d), having J{sup PC}=1{sup --}. To search for them, we analyse the BABAR data obtained during an energy scan of the e{sup +}e{sup -}{yields}b anti b cross section in the range of {radical}(s)=10.54 to 11.20 GeV. We find that these data are consistent with the presence of an additional b anti b state Y{sub [bq]} with a mass of 10.90 GeV and a width of about 30 MeV apart from the {upsilon}(5S) and {upsilon}(6S) resonances. A closeup of the energy region around the Y{sub [bq]}-mass may resolve this state in terms of the two mass eigenstates, Y{sub [b,l]} and Y{sub [b,h]}, with a mass difference, estimated as about 6 MeV. We tentatively identify the state Y{sub [bq]}(10900) from the R{sub b}-scan with the state Y{sub b}(10890) observed by BELLE in the process e{sup +}e{sup -}{yields}Y{sub b}(10890){yields}{upsilon}(1S,2S){pi}{sup +}{pi}{sup -} due to their proximity in masses and decay widths. (orig.)

Association of alkali and alkaline earth metal cations with radical-anions of 9-fluorenone and 9.10-anthraquinone in dimethyl formamide medium

International Nuclear Information System (INIS)

Karpinets, A.P.; Bezuglyj, V.D.; Svetlichnaya, T.M.

1988-01-01

The polarographic method is used to estimate the stability of associates formed in dimethyl formamide by the products of one-electron reduction of 9-fluorenone and 9.10-anthraquinone with cations of alkali and alkali earth metals. It is shown that the strength of 9-fluorenone and 9.10-anthraquinone radical anion associates studied increases with cation charge increase and decrease of its crystallographic radius

Myocardial capillary permeability after regional ischemia and reperfusion in the in vivo canine heart. Effect of superoxide dismutase

DEFF Research Database (Denmark)

Svendsen, J H; Bjerrum, P J; Haunsø, S

1991-01-01

This study assesses the effect of the superoxide anion scavenger superoxide dismutase on myocardial capillary permeability-surface area (PS) products for small hydrophilic molecules after ischemia and reperfusion. Open-chest dogs underwent a 20-minute occlusion of the left anterior descending...... the start of reperfusion. In 13 dogs, no scavenger treatment was given (nonprotected control group), whereas eight dogs were treated systemically with 15,000 units/kg superoxide dismutase during 1 hour, starting 20 minutes before ischemia. In the control group, three dogs developed reperfusion ventricular...

Umbelliferone: Sources, chemistry and bioactivities review

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Ofentse Mazimba

2017-12-01

Full Text Available Umbelliferone is a 7-hydroxycoumarin that is a pharmacologically active agent. It is widely distributed within the Rutaceae and Apiaceae (Umbelliferae families and is efficiently extracted using methanol. Umbelliferone is a fluorescing compound used as a sunscreen agent. It is synthesized using the Pechmann condensation reaction of resorcinol and formyl acetic acid. Biosynthetically it is synthesized using the phenylpropanoid pathway. Umbelliferone is a synthon for other coumarins and heterocycles with improved biological activities. In the Literature modest antibacterial and antifungal activities are reported with MIC values of 500–1000 μg/mL, but exhibited good E. coli anti-biofilm formation. Umbelliferone shows good inhibitions of DPPH, hydroxyl, superoxide anion and ABTS radicals. Other reported activities are anti-inflammatory, anti-hyperglycaemic, molluscicidal and anti-tumor activities. Keywords: Umbelliferone, Anti-bacterial, Anti-tumor, Cytotoxicity, Synthesis, Biosynthesis

Peculiarities of the free radical processes in rat liver mitochondria under toxic hepatitis on the background of alimentary protein deficiency

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G. P. Kopylchuk

2016-04-01

Full Text Available The rate of superoxide anion radical, hydroxyl radical and hydrogen peroxide generation, the level of oxidative modification of mitochondrial proteins in the liver of rats with toxic hepatitis was investigated on the background of alimentary protein deficiency. We did not find significant increases of the intensity of free radical processes in liver mitochondria of rats maintained on the protein-deficient ration. The most significant intensification of free radical processes in liver mitochondria is observed under the conditions of toxic hepatitis, induced on the background of alimentary protein deprivation. Under these conditions the aggravation of all studied forms of reactive oxygen species generation was observed in liver mitochondria. The generation rates were increased as follows: O2 – by 1.7 times, Н2О2 – by 1.5 times, •ОН – practically double on the background of accumulation of oxidized mitochondria-derived proteins. The established changes in thiol groups’ redox status of respiratory chain proteins insoluble in 0.05 M sodium-phosphate buffer (pH 11.5, and changes of their carbonyl derivatives content may be considered as one of the regulatory factors of mitochondrial energy-generating function.

Effect of Rubia cordifolia, Fagonia cretica linn, and Tinospora cordifolia on free radical generation and lipid peroxidation during oxygen-glucose deprivation in rat hippocampal slices

International Nuclear Information System (INIS)

Rawal, Avinash; Muddeshwar, Manohar; Biswas, Saibal

2004-01-01

The major damaging factor during and after the ischemic/hypoxic insult is the generation of free radicals, which leads to apoptosis, necrosis, and ultimately cell death. Rubia cordifolia (RC), Fagonia cretica linn (FC), and Tinospora cordifolia (TC) have been reported to contain a wide variety of antioxidants and have been in use in the eastern system of medicine for various disorders. Hippocampal slices were subjected to oxygen-glucose deprivation (OGD) and divided into three groups, control, OGD, and OGD+drug treated. Cytosolic reduced glutathione (GSH), nitric oxide [NO, measured as nitrite (NO 2 )]. EPR was used to establish the antioxidant effect of RC, FC, and TC with respect to superoxide anion (O2-), hydroxyl radicals (OH), nitric oxide (NO) radical, and peroxynitrite anion (ONOO - ) generated from pyrogallol, menadione, DETA-NO, and Sin-1, respectively. RT-PCR was performed for the three herbs to assess their effect on the expression of γ-glutamylcysteine ligase (GCLC), iNOS, and GAPDH gene expression. All the three herbs were effective in elevating the GSH levels and expression of the GCLC. The herbs also exhibited strong free radical scavenging properties against reactive oxygen and nitrogen species as revealed by electron paramagnetic resonance spectroscopy, diminishing the expression of iNOS gene. RC, FC, and TC therefore attenuate oxidative stress mediated cell injury during OGD and exert the above effects at both the cytosolic as well as at gene expression levels and may be effective therapeutic tool against ischemic brain damage

A study on superoxide dismutase activity of some model compounds.

Science.gov (United States)

Liao, Z; Liu, W; Liu, J; Jiang, Y; Shi, J; Liu, C

1994-08-15

The synthesis and characteristics of a binuclear ligand N,N,N',N'-tetrakis (2'-benzimidazolyl methyl)-1,4-diethylene amino glycol ether (EGTB) and its series of coordination compounds containing copper(II), iron(III), and manganese(II) with and without exogenous bridging ligand which was imidazolate ion (Im-), bipyridine (bpy), or 1,10-phenanthroline (phen) are reported. Depending on the redox potentials by cyclic voltammetry, the coordination compounds can act as catalysts for the dismutation of superoxide radicals (O2-). The detection of the rate constant of the reaction of superoxide ion with nitroblue tetrazolium (NBT) which is inhibited by superoxide dismutase (SOD) and its model compounds of the EGTB system has been performed by a modified illumination method. The rate constants kQ of the catalytic dismutation have been obtained.

Preparation of high-capacity, weak anion-exchange membranes by surface-initiated atom transfer radical polymerization of poly(glycidyl methacrylate) and subsequent derivatization with diethylamine

International Nuclear Information System (INIS)

Qian, Xiaolei; Fan, Hua; Wang, Chaozhan; Wei, Yinmao

2013-01-01

Ion-exchange membrane is of importance for the development of membrane chromatography. In this work, a high-capacity anion-exchange membrane was prepared by grafting of glycidyl methacrylate (GMA) onto the surface of regenerated cellulose (RC) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequent derivatization with diethylamine. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize changes in the chemical functionality, surface topography and pore morphology of the modified membranes. The static capacity of the prepared anion-exchange membrane was evaluated with bovine serum albumin (BSA) as a model protein. The results indicated that the anion-exchange membrane which could reach a maximum capacity of 96 mg/mL for static adsorption possesses a higher adsorption capacity, and the adsorption capacity increases with the polymerization time. The effect of pH and salt concentration confirmed that the adsorption of BSA followed ion-exchange mechanism. The established method would have potential application in the preparation of anion-exchange membrane.

Electron spin resonance and optical studies on the radiolysis of carbon tetrachloride. II. Structure and reaction of CClṡ-4 radical anion in tetramethylsilane low-temperature solids

Science.gov (United States)

Muto, Hachizo; Nunome, Keichi

1991-04-01

An electron spin resonance (ESR) and optical study of carbon tetrachloride radical anion has been made to provide for a better understanding of the radiolysis of CCl4, following CClṡ+4 cation previously studied. It was found that the anion was metastably trapped in tetramethylsilane (TMS) matrices γ irradiated at 4 or 77 K. The g tensor and the hyperfine coupling tensors of all atoms of the radical were determined from ESR spectral simulation by using 12 CCl4 and the 13C enriched compound: g∥=2.004-5, g1=2.015,(A∥,A⊥) =(24.3,18.3) mT for 13C, (0.9, 0.2) mT for one 35Cl atom, and (A1,A2=A3)=(1.98,0.45) mT for the other three equivalent 35Cl atoms. From these parameters and a consideration on the g anisotropy combined with the optical data, the anion was found to have a predissociating molecular structure (CCl3ṡṡṡCl) ˙- with C3v symmetry, where the unpaired electron occupies A*1γ antibonding orbital. The carbon atom has a large spin density and near sp3 hybridization: ρp=0.62, ρs=0.18, ρp/ρs=3.4, and three Cl atoms and the other Cl atom have the spin densities ρp=0.10 and ρp=0.05, respectively. The species had two optical absorptions at λmax=265 and 370 nm which were assigned to the Eγ-A*1γ and A1γ-A*1γ electronic transitions, respectively. The anion converted to CCl ṡ3 radical by warming to ˜150 K in the TMS matrix. The present results have given unequivocal ESR and optical spectroscopic evidence and support for the assignment of the 370 nm band reported in the radiolyses of organic solutions containing CCl4.

Radical scavenging activity of crude polysaccharides from Camellia sinensis

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Yang Fan

2011-01-01

Full Text Available A preparation of crude polysaccharides (TPS was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.

Anti-oxidation and scavenging effects of some extracts from Chinese medicines on free radicals

International Nuclear Information System (INIS)

Wang Chongdao; Qiang Yizhong; Lao Qinhua; Cui Fengmei; Shao Yuan; Sun Cunpu

1999-11-01

The inhibiting effects of Chinonin, Quercetin and Tannic Acid on the lipid oxidation induced by radiation exposure were investigated by means of a modified TBA spectrophotometry. The scavenging effects on free radicals caused by γ-irradiation exposure of the three active principles were observed by technique of ESR. The results showed that anti-oxidation effects of Chinonin and Quercetin were better than that of Tannic Acid, while the scavenging effects of the three active principles on free radicals were similar

Radical pair formation in γ-irradiated 2-methyltetrahydrofuran rigid solutions of polynitrobenzenes

International Nuclear Information System (INIS)

Konishi, S.; Hoshino, M.; Imamura, M.

1981-01-01

The γ-irradiated MTHF (2-methyltetrahydrofuran) rigid solutions of mDNB (m-dinitrobenzene) and sTNB (s-trinitrobenzene) showed at 77 K ESR spectra characteristic of triplet species in addition to the spectra of doublet species, whereas no triplet ESR spectra were observed for the mononitrobenzene and o- and p-di-nitrobenzene solutions. The distances of the unpaired spins evaluated from the observed fine structure constants by using a point-dipole approximation are 4.3 and 4.6 A for the mDNB solution and 3.9 and 4.7 A for the sTNB solution. The detection of only the solute anion radicals by the optical absorption spectra of the irradiated solutions and the difference of the rate of formation for the triplet species and the solute anion strongly suggest that the triplet species are ascribed to the solute anion-solvent radical pairs. Such radical pairs are most likely to be formed through the migration of a MTHF cation radical, i.e., so-called hole migration, to a specific site between the two nitro groups on the meta positions of a solute anion followed by the production of a stable solvent radical, which is paired with the solute anion

Evidences of extracellular abiotic degradation of hexadecane through free radical mechanism induced by the secreted phenazine compounds of P. aeruginosa NY3.

Science.gov (United States)

Nie, Hongyun; Nie, Maiqian; Wang, Lei; Diwu, Zhenjun; Xiao, Ting; Qiao, Qi; Wang, Yan; Jiang, Xin

2018-03-02

The aim of this work was to investigate the effects of secreted extracellular phenazine compounds (PHCs) on the degradation efficiency of alkanes by P. aeruginosa NY3. Under aerobic conditions, the PHCs secreted by P. aeruginosa NY3 initiate the oxidation of alkanes outside cells, in coupling with some reducing agents, such as β-Nicotinamide adenine dinucleotide, reduced disodium salt (NADH) or reduced glutathione (GSH). This reaction might be via free radical reactions similar to Fenton Oxidation Reaction (FOR). P. aeruginosa NY3 secretes pyocyanin (Pyo), 1-hydroxyphenazine (HPE), phenazine-1-carboxylic acid (PCA), and phenazine-1-amide (PCN) simultaneously. The cell-free extracellular fluid containing these four PHCs degrades hexadecane effectively. The observation of Electron Spin Resonance (EPR) signals of superoxide anion radical (O 2 - ), hydroxyl radical (OH) and/or carbon free radicals (R) both in vivo and in vitro suggested the degradation of hexadecane could be via a free radical pathway. Secretion of PHCs has been found to be characteristic of Pseudomonas which is often involved in or related to the degradation of organic pollutants. Our work suggested that certain organic contaminants may be oxidized through ubiquitously extracellular abiotic degradation by the free radicals produced during bio-remediation and bio-treatment. Copyright © 2018. Published by Elsevier Ltd.

The nature of the CO{sub 2}{sup −} radical anion in water

Energy Technology Data Exchange (ETDEWEB)

Janik, Ireneusz; Tripathi, G. N. R. [Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2016-04-21

The reductive conversion of CO{sub 2} into industrial products (e.g., oxalic acid, formic acid, methanol) can occur via aqueous CO{sub 2}{sup −} as a transient intermediate. While the formation, structure, and reaction pathways of this radical anion have been modelled for decades using various spectroscopic and theoretical approaches, we present here, for the first time, a vibrational spectroscopic investigation in liquid water, using pulse radiolysis time-resolved resonance Raman spectroscopy for its preparation and observation. Excitation of the radical in resonance with its 235 nm absorption displays a transient Raman band at 1298 cm{sup −1}, attributed to the symmetric CO stretch, which is at ∼45 cm{sup −1} higher frequency than in inert matrices. Isotopic substitution at C ({sup 13}CO{sub 2}{sup −}) shifts the frequency downwards by 22 cm{sup −1}, which confirms its origin and the assignment. A Raman band of moderate intensity compared to the stronger 1298 cm{sup −1} band also appears at 742 cm{sup −1} and is assignable to the OCO bending mode. A reasonable resonance enhancement of this mode is possible only in a bent CO{sub 2}{sup −}(C{sub 2v}/C{sub s}) geometry. These resonance Raman features suggest a strong solute-solvent interaction, the water molecules acting as constituents of the radical structure, rather than exerting a minor solvent perturbation. However, there is no evidence of the non-equivalence (C{sub s}) of the two CO bonds. A surprising resonance Raman feature is the lack of overtones of the symmetric CO stretch, which we interpret due to the detachment of the electron from the CO{sub 2}{sup −} moiety towards the solvation shell. Electron detachment occurs at the energies of 0.28 ± 0.03 eV or higher with respect to the zero point energy of the ground electronic state. The issue of acid-base equilibrium of the radical, which has been in contention for decades, as reflected in a wide variation in the reported pK{sub a} (−0

Research concerning ionic and free radical reactions in radiation chemistry. Progress report, September 15, 1976--September 15, 1977

International Nuclear Information System (INIS)

Williams, T.F.

1977-01-01

Progress is reported on ESR studies of fluorocarbon radicals and intermediate radicals. A detailed study was made of the dimethyl, diethyl, and di-n-propyl carbonates. Studies were continued on hydrogen-atom abstraction reactions at low temperatures with view to evaluating the contribution from quantum-mechanical tunneling. Detection of the transient dimer radical anion of acetonitrile in the upper crystalline phase at -50 0 C is reported. Abstracts of current reports are included on electron attachment to fluorocarbons hydrogen atom abstraction by methyl radicals. EPR spectra of the tetrafluoroethylene radical anion, and addition of tetrafluoroethylene to the tetrafluoroethylene radical anion

Occupational exposure to ionizing radiation as a risk factor for free-radicals mediated diseases

International Nuclear Information System (INIS)

Djurovic, B.; Spasic-Jokic, V.; Selakovic, V.

2007-01-01

Complete text of publication follows. It was experimentally showed, that the exposure to low doses of ionizing radiation (IR) result in over-production of oxygen derived free radicals with inverse dose-rate effect. The oxidative stress that follows, especially cell membrane damage, was considered by Petkau, as crucial step in the induction of radiation injuries. From clinical research and practice with other unexposed patients is known that this type of cell damage can lead to an impairment of cellular function and can cause many free-radicals mediated diseases, such as atherosclerosis, damage of heart muscles, inflammatory and immuno-reactive lesions, senile dementia, cancer, etc. The aim of this paper is to investigate if occupational exposure to low doses of IR change the redox status of exposed personnel, and if so, is it the additional risk factor for free-radicals mediated diseases. Subjects: 77 medical workers, devided in two groups: 44 occupationally exposed to ionizing radiation (E), and 33 controls (C), matched in age, gender, habits-daitary, alcohol consumption, smoking and exposure time, were examined. Methods: Radiation dose accumulated over years was calculated on the basis of individual TL-dose records. Superoxide-anion and MDA production, as well as SOD (MnSOD, CuZnSOD) and GSH activity were determined in blood samples spectrophotometrically. Results: Significantly higher incidence of cataract, and higher, but not significant, incidence of cardiovascular diseases was noticed in exposed. Our results also confirmed significantly higher superoxide and MDA production (p=0.0049, 0.000028, respectively), as well as, increased activity of MnSOD and CuZnSOD (p0.0105, 0.001, respectively), and decreased level of GSH (p=0.0599) in exposed. Conclusions: Our results showed that low doses of IR could induce oxidative stress and for that reason could be considered as additional risk factor for free radical-mediated diseases. Further epidemiological studies are

Superoxide dismutases: Dual roles in controlling ROS damage and regulating ROS signaling.

Science.gov (United States)

Wang, Ying; Branicky, Robyn; Noë, Alycia; Hekimi, Siegfried

2018-04-18

Superoxide dismutases (SODs) are universal enzymes of organisms that live in the presence of oxygen. They catalyze the conversion of superoxide into oxygen and hydrogen peroxide. Superoxide anions are the intended product of dedicated signaling enzymes as well as the byproduct of several metabolic processes including mitochondrial respiration. Through their activity, SOD enzymes control the levels of a variety of reactive oxygen species (ROS) and reactive nitrogen species, thus both limiting the potential toxicity of these molecules and controlling broad aspects of cellular life that are regulated by their signaling functions. All aerobic organisms have multiple SOD proteins targeted to different cellular and subcellular locations, reflecting the slow diffusion and multiple sources of their substrate superoxide. This compartmentalization also points to the need for fine local control of ROS signaling and to the possibility for ROS to signal between compartments. In this review, we discuss studies in model organisms and humans, which reveal the dual roles of SOD enzymes in controlling damage and regulating signaling. © 2018 Wang et al.

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.

Extraction of erythrocyte enzymes for the preparation of polyhemoglobin-catalase-superoxide dismutase.

Science.gov (United States)

Gu, Jingsong; Chang, Thomas Ming Swi

2009-01-01

In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study on extracting these enzymes from red blood cells and analyzing the amount of enzymes needed for adequate protection from ischemia-reperfusion.

Dysbaric osteonecrosis (caisson disease of bone): are active oxygen species and the endocrine system responsible, and can control of the production of free radicals and their reaction products confer protection?

Science.gov (United States)

Jones, G R

1987-01-01

The development of osteonecrosis after exposure to altered air pressures is consistent with cellular injury brought about by active oxygen species. The syndrome is considered to arise as a result of an unusual combination of circumstances in which hyperoxia itself, together with the additive responses of the endocrine system to hyperoxia, hypothermia and exertion, each appear to play a part; the net result is thought to increase the mitochondrial generation of superoxide. It is suggested that effective prophylaxis may be possible primarily by establishing a nutritional status that is adequate to ensure that the functional activities of radical-scavenging systems are not hampered by deficiencies either of essential trace elements or of vitamin E. Pharmacological pretreatments designed both to decrease excessive levels of superoxide through increased catalysis of anionic dismutation and to attenuate enzyme-dependent peroxidation may provide an additional line of defence.

Polyphenol contents and radical scavenging capacities of red maple (Acer rubrum L.) extracts.

Science.gov (United States)

Royer, Mariana; Diouf, Papa Niokhor; Stevanovic, Tatjana

2011-09-01

The crude ethanol and water extracts of different red maple (Acer rubrum L.) tissues: whole branches (WB), wood of branches (BW), bark of branches (BB), stem bark (SB) and whole twigs (T), were examined in order to determine their phenolic contents as well as their radical scavenging capacities. The total phenols (TP), total extractable tanins (TET) and non-precipitable phenols (NPP), were determined by combination of spectrophotometric and precipitation methods, while total flavonoids, hydroxy cinanmic acids and proanthocyanidins were determined spectrophotometrically. The radical scavenging activities of the extracts were determined against five reactive oxygen species (ROS): superoxide anion (O(2)(·-)), hydroxyl radical (HO(·)), peroxyl radical (ROO(·)), hypochlorite ion (ClO(-)), and hydrogen peroxide (H(2)O(2)) and one reactive nitrogen species (RNS): nitric oxide (NO). The extracts of stem bark were significantly more efficient (exhibiting the highest antioxidant efficiencies, AE) than the other studied extracts against all ROS (at p<0.05, Duncan statistical tests), except against NO. The correlation coefficients determined between total phenolic (TP) content and antiradical efficiencies were R(2)=0.12 for O(2)(·-); R(2)=0.29 for HO(·); R(2)=0.40 for H(2)O(2); R(2)=0.86 for ROO(·); R(2)=0.03 for NO(·) and R(2)=0.73 for ClO(-). Our results indicate potential utilisation of extracts as natural antioxidants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Photophysics and Photochemistry of 2-Aminobenzoic Acid Anion in Aqueous Solution

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Pozdnyakov, Ivan P.; Plyusnin, Victor F.; Grivin, Vjacheslav P.

2009-11-01

Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA-) in aqueous solutions. Excitation of this species gives rise to the ABA- triplet state to the ABA• radical and to the hydrated electron (eaq-). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA- triplet state, the ABA• radical, and eaq- are T-T annihilation, recombination, and capture by the ABA- anion, respectively.

Antioxidant Activities of Total Pigment Extract from Blackberries

Directory of Open Access Journals (Sweden)

Jiechao Liu

2005-01-01

Full Text Available Total pigment has been extracted from blackberries and its antioxidant activity against lipid peroxidation and scavenging capacities towards superoxide anion radicals, hydroxyl radicals and nitrite in different in vitro systems have been investigated. The total pigment extract from blackberries (TPEB exhibited strong antioxidant activity against lipid peroxidation in a linoleic acid model system and scavenging capacities towards superoxide anion radicals, generated by a pyrogallol autoxidation system or by an illuminating riboflavin system, hydroxyl radicals generated by Fenton reaction, and nitrite. Furthermore, the antioxidant activities were correlated with the concentrations of the TPEB. In the test concentration range, the maximum inhibition percentage against linoleic acid peroxidation was 98.32 % after one week’s incubation, and the maximum scavenging percentages for the free radicals and nitrite inhibition in the above reactive systems reached 90.48, 96.48, 93.58 and 98.94 %, respectively. The TPEB is a natural, edible colorant with excellent antioxidant activities and health benefits and it seems to be applicable in both healthy food and medicine.

Shedding Light on the Oxygen Reduction Reaction Mechanism in Ether-Based Electrolyte Solutions: A Study Using Operando UV-Vis Spectroscopy.

Science.gov (United States)

Hirshberg, Daniel; Sharon, Daniel; Afri, Michal; Lavi, Ronit; Frimer, Aryeh A; Metoki, Noa; Eliaz, Noam; Kwak, Won-Jin; Sun, Yang-Kook; Aurbach, Doron

2018-04-04

Using UV-vis spectroscopy in conjunction with various electrochemical techniques, we have developed a new effective operando methodology for investigating the oxygen reduction reactions (ORRs) and their mechanisms in nonaqueous solutions. We can follow the in situ formation and presence of superoxide moieties during ORR as a function of solvent, cations, anions, and additives in the solution. Thus, using operando UV-vis spectroscopy, we found evidence for the formation of superoxide radical anions during oxygen reduction in LiTFSI/diglyme electrolyte solutions. Nitro blue tetrazolium (NBT) was used to indicate the presence of superoxide moieties based on its unique spectral response. Indeed, the spectral response of NBT containing solutions undergoing ORR could provide a direct indication for the level of association of the Li cations with the electrolyte anions.

X-ray effects of lens DNA-implications of superoxide (O2.-)

International Nuclear Information System (INIS)

Srivastava, V.K.; Richards, R.D.; Varma, S.D.

1983-01-01

The photocemical generation of superoxide (O 2 .-) during in vitro exposure of bovine lenses induced damage in the structure of lens DNA as indicated by hyperchromicity and Tm measurements. The damage in lens DNA was significantly protected by the inclusion of superoxide dismutase (SOD), glutathione (GSH) and ascorbate in the incubation medium before X-ray exposure. The protection by SOD, GSH and ascorbate occurred due to their interaction with O 2 .- radicals. These results thus indicate the deleterious effect of O 2 .- in lens physiology and the protective role of such compounds against radiation damage. (author)

Catalase and superoxide dismutase conjugated with platelet-endothelial cell adhesion molecule antibody distinctly alleviate abnormal endothelial permeability caused by exogenous reactive oxygen species and vascular endothelial growth factor.

Science.gov (United States)

Han, Jingyan; Shuvaev, Vladimir V; Muzykantov, Vladimir R

2011-07-01

Reactive oxygen species (ROS) superoxide anion (O(2)()) and hydrogen peroxide (H(2)O(2)) produced by activated leukocytes and endothelial cells in sites of inflammation or ischemia cause endothelial barrier dysfunction that may lead to tissue edema. Antioxidant enzymes (AOEs) catalase and superoxide dismutase (SOD) conjugated with antibodies to platelet-endothelial cell adhesion molecule-1 (PECAM-1) specifically bind to endothelium, quench the corresponding ROS, and alleviate vascular oxidative stress and inflammation. In the present work, we studied the effects of anti-PECAM/catalase and anti-PECAM/SOD conjugates on the abnormal permeability manifested by transendothelial electrical resistance decline, increased fluorescein isothiocyanate-dextran influx, and redistribution of vascular endothelial-cadherin in human umbilical vein endothelial cell (HUVEC) monolayers. Anti-PECAM/catalase protected HUVEC monolayers against H(2)O(2)-induced endothelial barrier dysfunction. Polyethylene glycol-conjugated catalase exerted orders of magnitude lower endothelial uptake and no protective effect, similarly to IgG/catalase. Anti-PECAM/catalase, but not anti-PECAM/SOD, alleviated endothelial hyperpermeability caused by exposure to hypoxanthine/xanthine oxidase, implicating primarily H(2)O(2) in the disruption of the endothelial barrier in this model. Thrombin-induced endothelial permeability was not affected by treatment with anti-PECAM/AOEs or the NADPH oxidase inhibitor apocynin or overexpression of AOEs, indicating that the endogenous ROS play no key role in thrombin-mediated endothelial barrier dysfunction. In contrast, anti-PECAM/SOD, but not anti-PECAM/catalase, inhibited a vascular endothelial growth factor (VEGF)-induced increase in endothelial permeability, identifying a key role of endogenous O(2)() in the VEGF-mediated regulation of endothelial barrier function. Therefore, AOEs targeted to endothelial cells provide versatile molecular tools for testing the roles of

Acetaminophen and aspirin inhibit superoxide anion generation and lipid peroxidation, and protect against 1-methyl-4-phenyl pyridinium-induced dopaminergic neurotoxicity in rats.

Science.gov (United States)

Maharaj, D S; Saravanan, K S; Maharaj, H; Mohanakumar, K P; Daya, S

2004-04-01

We assessed the antioxidant activity of non-narcotic analgesics, acetaminophen and aspirin in rat brain homogenates and neuroprotective effects in vivo in rats intranigrally treated with 1-methyl-4-phenyl pyridinium (MPP+). Both drugs inhibited cyanide-induced superoxide anion generation, as well as lipid peroxidation in rat brain homogenates, the combination of the agents resulting in a potentiation of this effect. Acetaminophen or aspirin when administered alone or in combination, did not alter dopamine (DA) levels in the forebrain or in the striatum. Intranigral infusion of MPP+ in rats caused severe depletion of striatal DA levels in the ipsilateral striatum in rats by the third day. Systemic post-treatment of acetaminophen afforded partial protection, whereas similar treatment of aspirin resulted in complete blockade of MPP+-induced striatal DA depletion. While these findings suggest usefulness of non-narcotic analgesics in neuroprotective therapy in neurodegenerative diseases, aspirin appears to be a potential candidate in prophylactic as well as in adjuvant therapy in Parkinson's disease.

Designing Superoxide-Generating Quantum Dots for Selective Light-Activated Nanotherapy

Science.gov (United States)

Goodman, Samuel M.; Levy, Max; Li, Fei-Fei; Ding, Yuchen; Courtney, Colleen M.; Chowdhury, Partha P.; Erbse, Annette; Chatterjee, Anushree; Nagpal, Prashant

2018-03-01

The rapid emergence of superbugs or multi-drug resistant (MDR) organisms has prompted a search for novel antibiotics, beyond traditional small-molecule therapies. Nanotherapeutics are being investigated as alternatives, and recently superoxide-generating quantum dots (QDs) have been shown as important candidates for selective light-activated therapy and potentiating existing antibiotics against MDR superbugs. Their therapeutic action is selective, can be tailored by simply changing their quantum-confined conduction-valence bands and their alignment with different redox half-reactions, and hence their ability to generate specific radical species in biological media. Here, we show the design of superoxide-generating QDs using optimal QD material and size well matched to superoxide redox potential, charged ligands to modulate their uptake in cells and selective redox interventions, and core/shell structures to improve their stability for therapeutic action. We show that cadmium telluride (CdTe) QDs with conduction band position at -0.5V with respect to Normal Hydrogen Electron (NHE) and visible 2.4 eV bandgap generate a large flux of selective superoxide radicals, thereby demonstrating the most effective light-activated therapy. Although the positively charged QDs demonstrate large cellular uptake, they bind indiscriminately to cell surfaces and cause non-selective cell death, while negatively charged and zwitterionic QD ligands reduce the uptake and allow selective therapeutic action via interaction with redox species. The stability of designed QDs in biologically-relevant media increases with the formation of core-shell QD structures, but an appropriate design of core-shell structures is needed to minimize any reduction in charge injection efficiency to adsorbed oxygen molecules (to form superoxide) and maintain similar quantitative generation of tailored redox species, as measured using electron paramagnetic resonance (EPR) spectroscopy and electrochemical

Designing Superoxide-Generating Quantum Dots for Selective Light-Activated Nanotherapy.

Science.gov (United States)

Goodman, Samuel M; Levy, Max; Li, Fei-Fei; Ding, Yuchen; Courtney, Colleen M; Chowdhury, Partha P; Erbse, Annette; Chatterjee, Anushree; Nagpal, Prashant

2018-01-01

The rapid emergence of superbugs, or multi-drug resistant (MDR) organisms, has prompted a search for novel antibiotics, beyond traditional small-molecule therapies. Nanotherapeutics are being investigated as alternatives, and recently superoxide-generating quantum dots (QDs) have been shown as important candidates for selective light-activated therapy, while also potentiating existing antibiotics against MDR superbugs. Their therapeutic action is selective, can be tailored by simply changing their quantum-confined conduction-valence band (CB-VB) positions and alignment with different redox half-reactions-and hence their ability to generate specific radical species in biological media. Here, we show the design of superoxide-generating QDs using optimal QD material and size well-matched to superoxide redox potential, charged ligands to modulate their uptake in cells and selective redox interventions, and core/shell structures to improve their stability for therapeutic action. We show that cadmium telluride (CdTe) QDs with conduction band (CB) position at -0.5 V with respect to Normal Hydrogen Electron (NHE) and visible 2.4 eV bandgap generate a large flux of selective superoxide radicals, thereby demonstrating the effective light-activated therapy. Although the positively charged QDs demonstrate large cellular uptake, they bind indiscriminately to cell surfaces and cause non-selective cell death, while negatively charged and zwitterionic QD ligands reduce the uptake and allow selective therapeutic action via interaction with redox species. The stability of designed QDs in biologically-relevant media increases with the formation of core-shell QD structures, but an appropriate design of core-shell structures is needed to minimize any reduction in charge injection efficiency to adsorbed oxygen molecules (to form superoxide) and maintain similar quantitative generation of tailored redox species, as measured using electron paramagnetic resonance (EPR) spectroscopy and

Investigation on flavonoid composition and anti free radical potential of Sida cordata.

Science.gov (United States)

Shah, Naseer Ali; Khan, Muhammad Rashid; Ahmad, Bushra; Noureen, Farah; Rashid, Umbreen; Khan, Rahmat Ali

2013-10-22

Sida cordata, a member of Family Malvaceae is used in folk medicine for various ailments including liver diseases. In this study we investigated, its flavonoid constituents, in vitro antioxidant potential against different free radicals and hepatoprotection against carbon tetrachloride (CCl4)-induced liver damage in rat. Dried powder of S. cordata whole plant was extracted with methanol and the resultant (SCME) obtained was fractionated with escalating polarity to obtain n-hexane fraction (SCHE), ethyl acetate fraction (SCEE), n-butanol fraction (SCBE) and the remaining soluble portion as aqueous fraction (SCAE). Diverse in vitro antioxidants assays such as DPPH, H2O2, •OH, ABTS, β-carotene bleaching assay, superoxide radical, lipid peroxidation, reducing power, and total antioxidant capacity were studied to assess scavenging potential of methanol extract and its derived fractions. On account of marked scavenging activity SCEE was selected to investigate the hepatoprotective potential against CCl4 induced toxicity in Sprague-Dawley male rats by assessing the level of serum markers (alkaline phosphatase, alanine transaminase, aspartate transaminase, lactate dehydrogenase, bilirubin, and γ-glutamyltransferase) and of liver antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione-S-transfers (GST), glutathione reductase (GSR), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH) and lipid peroxidation (TBARS). Histology of the liver was performed to study alteration in histoarchitecture. Existence of active flavonoids was established by thin layer chromatographic studies. Considerable amount of flavonoid and phenolic contents were recorded in the methanol extract and its derived fractions. Although the extract and all its derived fractions exhibited good antioxidant activities however, the most distinguished scavenging potential was observed for SCEE. Treatment of SCEE decreased the elevated level of serum

Oxygen and xenobiotic reductase activities of cytochrome P450.

NARCIS (Netherlands)

Goeptar, A.R.; Scheerens, H.; Vermeulen, N.P.E.

1995-01-01

The oxygen reductase and xenobiotic reductase activities of cytochrome P450 (P450) are reviewed. During the oxygen reductase activity of P450, molecular oxygen is reduced to superoxide anion radicals (O

Anti-inflammatory effects and anti-oxidant capacity of Myrathius arboreus (Cecropiaceae) in experimental models.

Science.gov (United States)

Oluwole, Oluwafemi Gabriel; Ologe, Olufunmilayo; Alabi, Akinyinka; Tunde Yusuf, Ganiyu; Umukoro, Solomon

2017-11-27

Inflammation is involved in various diseases; search for safe treatments is warranted. Anti-inflammatory effects of ethanol extract of Myrathius arboreus (EEMa) were studied in carrageenan-induced model, formaldehyde sub-acute-induced model, and in 48 h lipopolysaccharide-induced air pouch model of inflammation. EEMa membrane-stabilizing activities and anti-oxidant capacity were determined in vitro. In the carrageenan model EEMa (125, 250, or 500 mg/kg), indomethacin (5 mg/kg), or vehicle 3 mL/kg was administered orally in rats (n=5). After 1 h, 0.1 mL of 1% carrageenan was injected into the right hind paw of rats. Change in edema sizes was measured for 3 h with plethysmometer. One-tenth milliliter (0.1 mL) of 2.5% formaldehyde was injected into the rat paw on the first day and the third day to induce sub-acute inflammation; changes in the edema sizes were determined, and percentages of inhibitions were calculated. Anti-inflammatory effects of EEMa were further examined in lipopolysaccharide (LPS)-induced air-pouch based on leukocytes count, volume of exudates, levels of malondialdehyde, glutathione, superoxide dismutase, nitric oxides, and tumor necrosis factor released into the inflammatory fluids. EEMa-free radicals scavenging activities were studied in DPPH and reducing power tests. Membrane-stabilizing activities of EEMa were evaluated in the red blood cell lysis induced by thermal and hypotonic solution. EEMa (250, 500 mg/kg) produced significant (p<0.001; p<0.05) inhibition of inflammation when compared with vehicle. Also, EEMa (250, 500, or 1000 μg/mL) significantly stabilized membrane and produced free radical scavenging activities. M. arboreus possesses anti-inflammatory and the anti-oxidant properties that might benefit translational medicine.

Efficient scavenging of β-carotene radical cations by antiinflammatory salicylates

DEFF Research Database (Denmark)

Cheng, Hong; Liang, Ran; Han, Rui-Min

2014-01-01

by the anion of salicylic acid with 2.2 × 10 L mol s, but still of possible importance for light-exposed tissue. Surprisingly, acetylsalicylate, the aspirin anion, reacts with an intermediate rate in a reaction assigned to the anion of the mixed acetic-salicylic acid anhydride formed through base induced......The radical cation generated during photobleaching of β-carotene is scavenged efficiently by the anion of methyl salicylate from wintergreen oil in a second-order reaction approaching the diffusion limit with k = 3.2 × 10 L mol s in 9:1 v/v chloroform-methanol at 23 °C, less efficiently...... rearrangements. The relative scavenging rate of the β-carotene radical cation by the three salicylates is supported by DFT-calculations....

Natural montmorillonite induced photooxidation of As(III) in aqueous suspensions: Roles and sources of hydroxyl and hydroperoxyl/superoxide radicals

International Nuclear Information System (INIS)

Wang, Yajie; Xu, Jing; Li, Jinjun; Wu, Feng

2013-01-01

Highlights: • Natural montmorillonite contributes to photochemical oxidation of arsenite. • Ferrous ions significantly affect photochemical behavior of montmorillonite. • HO· and HO 2 ·/O 2 − · play different roles in this process. -- Abstract: Photooxidation of arsenite(As(III)) in a suspension of natural montmorillonite under the irradiation of metal halide lamp (λ ≥ 313 nm)has been investigated. The results showed that the natural montmorillonite induced the photooxidation of As(III) by generating hydroxyl radicals (HO·) and hydroperoxyl/superoxide radicals (HO 2 ·/O 2 − ·). HO· which was responsible for the As(III) photooxidation. Approximately 38% of HO· was generated by the photolysis of ferric ions, and the formation of the remaining 62% was strongly dependent on the HO 2 ·/O 2 − ·. The presence of free ironions (Fe 2+ and Fe 3+ ), made significant contributions to the photogeneration of these reactive oxygen species (ROS). The photooxidation of As(III) in natural montmorillonite suspensions was greatly influenced by the pH values. The photooxidation of As(III) by natural montmorillonite followed the Langmuir–Hinshelwood equation. In addition, the photooxidation of As(III) could be enhanced by the addition of humic acid. This work demonstrates that photooxidation may be an important environmental process for the oxidation of As(III) and may be a way to remove As(III) from acidic surface water containing iron-bearing clay minerals

Effect of Bothrops alternatus snake venom on macrophage phagocytosis and superoxide production: participation of protein kinase C

Directory of Open Access Journals (Sweden)

SS Setubal

2011-01-01

Full Text Available Envenomations caused by different species of Bothrops snakes result in severe local tissue damage, hemorrhage, pain, myonecrosis, and inflammation with a significant leukocyte accumulation at the bite site. However, the activation state of leukocytes is still unclear. According to clinical cases and experimental work, the local effects observed in envenenomation by Bothrops alternatus are mainly the appearance of edema, hemorrhage, and necrosis. In this study we investigated the ability of Bothrops alternatus crude venom to induce macrophage activation. At 6 to 100 ¼g/mL, BaV is not toxic to thioglycollate-elicited macrophages; at 3 and 6 ¼g/mL, it did not interfere in macrophage adhesion or detachment. Moreover, at concentrations of 1.5, 3, and 6 ¼g/mL the venom induced an increase in phagocytosis via complement receptor one hour after incubation. Pharmacological treatment of thioglycollate-elicited macrophages with staurosporine, a protein kinase (PKC inhibitor, abolished phagocytosis, suggesting that PKC may be involved in the increase of serum-opsonized zymosan phagocytosis induced by BaV. Moreover, BaV also induced the production of anion superoxide (O2_ by thioglycollate-elicited macrophages. This BaV stimulated superoxide production was abolished after treating the cells with staurosporine, indicating that PKC is an important signaling pathway for the production of this radical. Based on these results, we suggest that phagocytosis and reactive oxygen species are involved in the pathogenesis of local tissue damage characteristic of Bothrops spp. envenomations.

Enabling the high capacity of lithium-rich anti-fluorite lithium iron oxide by simultaneous anionic and cationic redox

Science.gov (United States)

Zhan, Chun; Yao, Zhenpeng; Lu, Jun; Ma, Lu; Maroni, Victor A.; Li, Liang; Lee, Eungje; Alp, Esen E.; Wu, Tianpin; Wen, Jianguo; Ren, Yang; Johnson, Christopher; Thackeray, Michael M.; Chan, Maria K. Y.; Wolverton, Chris; Amine, Khalil

2017-12-01

Anionic redox reactions in cathodes of lithium-ion batteries are allowing opportunities to double or even triple the energy density. However, it is still challenging to develop a cathode, especially with Earth-abundant elements, that enables anionic redox activity for real-world applications, primarily due to limited strategies to intercept the oxygenates from further irreversible oxidation to O2 gas. Here we report simultaneous iron and oxygen redox activity in a Li-rich anti-fluorite Li5FeO4 electrode. During the removal of the first two Li ions, the oxidation potential of O2- is lowered to approximately 3.5 V versus Li+/Li0, at which potential the cationic oxidation occurs concurrently. These anionic and cationic redox reactions show high reversibility without any obvious O2 gas release. Moreover, this study provides an insightful guide to designing high-capacity cathodes with reversible oxygen redox activity by simply introducing oxygen ions that are exclusively coordinated by Li+.

A novel theory: biological processes mostly involve two types of mediators, namely general and specific mediators Endogenous small radicals such as superoxide and nitric oxide may play a role of general mediator in biological processes.

Science.gov (United States)

Mo, Jian

2005-01-01

A great number of papers have shown that free radicals as well as bioactive molecules can play a role of mediator in a wide spectrum of biological processes, but the biological actions and chemical reactivity of the free radicals are quite different from that of the bioactive molecules, and that a wide variety of bioactive molecules can be easily modified by free radicals due to having functional groups sensitive to redox, and the significance of the interaction between the free radicals and the bioactive molecules in biological processes has been confirmed by the results of some in vitro and in vivo studies. Based on these evidence, this article presented a novel theory about the mediators of biological processes. The essentials of the theory are: (a) mediators of biological processes can be classified into general and specific mediators; the general mediators include two types of free radicals, namely superoxide and nitric oxide; the specific mediators include a wide variety of bioactive molecules, such as specific enzymes, transcription factors, cytokines and eicosanoids; (b) a general mediator can modify almost any class of the biomolecules, and thus play a role of mediator in nearly every biological process via diverse mechanisms; a specific mediator always acts selectively on certain classes of the biomolecules, and may play a role of mediator in different biological processes via a same mechanism; (c) biological processes are mostly controlled by networks of their mediators, so the free radicals can regulate the last consequence of a biological process by modifying some types of the bioactive molecules, or in cooperation with these bioactive molecules; the biological actions of superoxide and nitric oxide may be synergistic or antagonistic. According to this theory, keeping the integrity of these networks and the balance between the free radicals and the bioactive molecules as well as the balance between the free radicals and the free radical scavengers

The neuroprotective properties of the superoxide dismutase mimetic tempol correlate with its ability to reduce pathological glutamate release in a rodent model of stroke

Science.gov (United States)

Dohare, Preeti; Hyzinski-García, María C.; Vipani, Aarshi; Bowens, Nicole H.; Nalwalk, Julia W.; Feustel, Paul J.; Keller, Richard W.; Jourd’heuil, David; Mongin, Alexander A.

2014-01-01

The contribution of oxidative stress to ischemic brain damage is well established. Nevertheless, for unknown reasons, several clinically tested antioxidant therapies failed to show benefits in human stroke. Based on our previous in vitro work, we hypothesized that the neuroprotective potency of antioxidants is related to their ability to limit release of the excitotoxic amino acids, glutamate and aspartate. We explored the effects of two antioxidants, tempol and edaravone, on amino acid release in the brain cortex, in a rat model of transient occlusion of the middle cerebral artery (MCAo). Amino acid levels were quantified using a microdialysis approach, with the probe positioned in the ischemic penumbra as verified by a laser Doppler technique. Two-hour MCAo triggered a dramatic increase in the levels of glutamate, aspartate, taurine and alanine. Microdialysate delivery of 10 mM tempol reduced the amino acid release by 60–80%, while matching levels of edaravone had no effect. In line with these latter data, an intracerebroventri-cular injection of tempol but not edaravone (500 nmols each, 15 minutes prior to MCAo) reduced infarction volumes by ~50% and improved neurobehavioral outcomes. In vitro assays showed that tempol was superior in removing superoxide anion, whereas edaravone was more potent in scavenging hydrogen peroxide, hydroxyl radical, and peroxynitrite. Overall, our data suggests that the neuroprotective properties of tempol are likely related to its ability to reduce tissue levels of the superoxide anion and pathological glutamate release, and, in such a way, limit progression of brain infarction within ischemic penumbra. These new findings may be instrumental in developing new antioxidant therapies for treatment of stroke. PMID:25224033

Arsenic alters monocyte superoxide anion and nitric oxide production in environmentally exposed children

International Nuclear Information System (INIS)

Luna, Ana L.; Acosta-Saavedra, Leonor C.; Lopez-Carrillo, Lizbeth; Conde, Patricia; Vera, Eunice; De Vizcaya-Ruiz, Andrea; Bastida, Mariana; Cebrian, Mariano E.; Calderon-Aranda, Emma S.

2010-01-01

Arsenic (As) exposure has been associated with alterations in the immune system, studies in experimental models and adults have shown that these effects involve macrophage function; however, limited information is available on what type of effects could be induced in children. The aim of this study was to evaluate effects of As exposure, through the association of inorganic As (iAs) and its metabolites [monomethylated arsenic (MMA) and dimethylated arsenic (DMA)] with basal levels of nitric oxide (NO ·- ) and superoxide anion (O 2 ·- ), in peripheral blood mononuclear cells (PBMC) and monocytes, and NO ·- and O 2 ·- produced by activated monocytes. Hence, a cross-sectional study was conducted in 87 children (6-10 years old) who had been environmentally exposed to As through drinking water. Levels of urinary As species (iAs, MMA and DMA) were determined by hydride generation atomic absorption spectrometry, total As (tAs) represents the sum of iAs and its species; tAs urine levels ranged from 12.3 to 1411 μg/g creatinine. Using multiple linear regression models, iAs presented a positive and statistical association with basal NO ·- in PBMC (β = 0.0048, p = 0.049) and monocytes (β = 0.0044, p = 0.044), while basal O 2 ·- had a significant positive association with DMA (β = 0.0025, p = 0.046). In activated monocytes, O 2 ·- showed a statistical and positive association with iAs (β = 0.0108, p = 0.023), MMA (β = 0.0066, p = 0.022), DMA (β = 0.0018, p = 0.015), and tAs (β = 0.0013, p = 0.015). We conclude that As exposure in the studied children was positively associated with basal levels of NO ·- and O 2 ·- in PBMC and monocytes, suggesting that As induces oxidative stress in circulating blood cells. Additionally, this study showed a positive association of O 2 ·- production with iAs and its metabolites in stimulated monocytes, supporting previous data that suggests that these cells, and particularly the O 2 ·- activation pathway, are relevant targets

2',3-dihydroxy-5-methoxybiphenyl suppresses fMLP-induced superoxide anion production and cathepsin G release by targeting the β-subunit of G-protein in human neutrophils.

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Liao, Hsiang-Ruei; Chen, Ih-Sheng; Liu, Fu-Chao; Lin, Shinn-Zhi; Tseng, Ching-Ping

2018-06-15

This study investigates the effect and the underlying mechanism of 2',3-dihydroxy-5-methoxybiphenyl (RIR-2), a lignan extracted from the roots of Rhaphiolepis indica (L.) Lindl. ex Ker var. tashiroi Hayata ex Matsum. & Hayata (Rosaceae), on N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced respiratory burst and cathepsin G in human neutrophils. Signaling pathways regulated by RIR-2 which modulated fMLP-induced respiratory burst were evaluated by an interaction between β subunit of G-protein (Gβ) with downstream signaling induced by fMLP and by immunoblotting analysis of the downstream targets of Gβ-protein. RIR-2 inhibited fMLP-induced superoxide anion production (IC 50 :2.57 ± 0.22 μM), cathepsin G release (IC 50 :18.72 ± 3.76 μM) and migration in a concentration dependent manner. RIR-2 specifically suppresses fMLP-induced Src family kinases phosphorylation by inhibiting the interaction between Gβ-protein with Src kinases without inhibiting Src kinases activities, therefore, RIR-2 attenuated the downstream targets of Src kinase, such as phosphorylation of Raf/ERK, AKT, P38, PLCγ2, PKC and translocation Tec, p47 ph ° x and P40 ph ° x from the cytosol to the inner leaflet of the plasma membrane. Furthermore, RIR-2 attenuated fMLP-induced intracellular calcium mobilization by inhibiting the interaction between Gβ-protein with PLCβ2. RIR-2 was not a competitive or allosteric antagonist of fMLP. On the contrary, phorbol 12-myristate 13-acetate (PMA)-induced phosphorylation of Src, AKT, P38, PKC and membrane localization of p47 ph ° x and P40 ph ° x remained unaffected. RIR-2 specifically modulates fMLP-mediated neutrophil superoxide anion production and cathepsin G release by inhibiting the interaction between Gβ-protein with downstream signaling which subsequently interferes with the activation of intracellular calcium, PLCγ2, AKT, p38, PKC, ERK, p47 ph ° x and p40 phox . Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of yogic exercise on superoxide dismutase levels in diabetics

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Mahapure Hemant

2008-01-01

Full Text Available Context: Reactive oxygen species are known to aggravate disease progression. To counteract their harmful effects, the body produces various antioxidant enzymes, viz , superoxide dismutase, glutathione reductase etc. Literature reviews revealed that exercises help to enhance antioxidant enzyme systems; hence, yogic exercises may be useful to combat various diseases. Aims: This study aims to record the efficacy of yoga on superoxide dismutase, glycosylated hemoglobin (Hb and fasting blood glucose levels in diabetics. Settings and Design: Forty diabetics aged 40-55 years were assigned to experimental (30 and control (10 groups. The experimental subjects underwent a Yoga program comprising of various Asanas (isometric type exercises and Pranayamas (breathing exercises along with regular anti-diabetic therapy whereas the control group received anti-diabetic therapy only. Methods and Material: Heparinized blood samples were used to determine erythrocyte superoxide dismutase (SOD activity and glycosylated Hb levels and fasting blood specimens collected in fluoride Vacutainers were used for assessing blood glucose. Statistical analysis used: Data were analyzed by using 2 x 2 x 3 Factorial ANOVA followed by Scheffe′s posthoc test. Results: The results revealed that Yogic exercise enhanced the levels of Superoxide dismutase and reduced glycosylated Hb and glucose levels in the experimental group as compared to the control group. Conclusion: The findings conclude that Yogic exercises have enhanced the antioxidant defence mechanism in diabetics by reducing oxidative stress.

Dark production of extracellular superoxide by the coral Porites astreoides and representative symbionts

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Tong Zhang

2016-11-01

Full Text Available The reactive oxygen species (ROS superoxide has been implicated in both beneficial and detrimental processes in coral biology, ranging from pathogenic disease resistance to coral bleaching. Despite the critical role of ROS in coral health, there is a distinct lack of ROS measurements and thus an incomplete understanding of underpinning ROS sources and production mechanisms within coral systems. Here, we quantified in situ extracellular superoxide concentrations at the surfaces of aquaria-hosted Porites astreoides during a diel cycle. High concentrations of superoxide (~10’s of nM were present at coral surfaces, and these levels did not change significantly as a function of time of day. These results indicate that the coral holobiont produces extracellular superoxide in the dark, independent of photosynthesis. As a short-lived anion at physiological pH, superoxide has a limited ability to cross intact biological membranes. Further, removing surface mucus layers from the P. astreoides colonies did not impact external superoxide concentrations. We therefore attribute external superoxide derived from the coral holobiont under these conditions to the activity of the coral host epithelium, rather than mucus-derived epibionts or internal sources such as endosymbionts (e.g., Symbiodinium. However, endosymbionts likely contribute to internal ROS levels via extracellular superoxide production. Indeed, common coral symbionts, including multiple strains of Symbiodinium (clades A to D and the bacterium Endozoicomonas montiporae LMG 24815, produced extracellular superoxide in the dark and at low light levels. Further, representative P. astreoides symbionts, Symbiodinium CCMP2456 (clade A and E. montiporae, produced similar concentrations of superoxide alone and in combination with each other, in the dark and low light, and regardless of time of day. Overall, these results indicate that healthy, non-stressed P. astreoides and representative symbionts produce

Oxidative generation of guanine radicals by carbonate radicals and their reactions with nitrogen dioxide to form site specific 5-guanidino-4-nitroimidazole lesions in oligodeoxynucleotides.

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Joffe, Avrum; Mock, Steven; Yun, Byeong Hwa; Kolbanovskiy, Alexander; Geacintov, Nicholas E; Shafirovich, Vladimir

2003-08-01

A simple photochemical approach is described for synthesizing site specific, stable 5-guanidino-4-nitroimidazole (NIm) adducts in single- and double-stranded oligodeoxynucleotides containing single and multiple guanine residues. The DNA sequences employed, 5'-d(ACC CG(1)C G(2)TC CG(3)C G(4)CC) and 5'-d(ACC CG(1)C G(2)TC C), were a portion of exon 5 of the p53 tumor suppressor gene, including the codons 157 (G(2)) and 158 (G(3)) mutation hot spots in the former sequence with four Gs and the codon 157 (G(2)) mutation hot spot in the latter sequence with two Gs. The nitration of oligodeoxynucleotides was initiated by the selective photodissociation of persulfate anions to sulfate radicals induced by UV laser pulses (308 nm). In aqueous solutions, of bicarbonate and nitrite anions, the sulfate radicals generate carbonate anion radicals and nitrogen dioxide radicals by one electron oxidation of the respective anions. The guanine residue in the oligodeoxynucleotide is oxidized by the carbonate anion radical to form the neutral guanine radical. While the nitrogen dioxide radicals do not react with any of the intact DNA bases, they readily combine with the guanine radicals at either the C8 or the C5 positions. The C8 addition generates the well-known 8-nitroguanine (8-nitro-G) lesions, whereas the C5 attack produces unstable adducts, which rapidly decompose to NIm lesions. The maximum yields of the nitro products (NIm + 8-nitro-G) were typically in the range of 20-40%, depending on the number of guanine residues in the sequence. The ratio of the NIm to 8-nitro-G lesions gradually decreases from 3.4 in the model compound, 2',3',5'-tri-O-acetylguanosine, to 2.1-2.6 in the single-stranded oligodeoxynucleotides and to 0.8-1.1 in the duplexes. The adduct of the 5'-d(ACC CG(1)C G(2)TC C) oligodeoxynucleotide containing the NIm lesion in codon 157 (G(2)) was isolated in HPLC-pure form. The integrity of this adduct was established by a detailed analysis of exonuclease digestion

Studies on protective effects of superoxide dismutase on radiation induced-chromosomal aberrations

International Nuclear Information System (INIS)

Zheng Siying; Jiang Jiagui; Lin Xingcheng

1987-09-01

This study demonstrates that radiation induced-chromosomal aberrations are not only due to the direct effect of radiation h it , but the indirect effect of free radical as well. Therefore, chromosome damage induced by radiation may be reduced by adding exogenous SOD into the radiation exposed lymphocyte culture to eliminate the superoxide free radical which damages DNA. On the other hand, however, the radiosensitivity of lymphocytes can be raised by adding SOD inhibitor (DDC) into the lymphocyte culture, which makes radiation induced-chromosomal damages more severely

Free radicals created by radiation and aging symptoms

International Nuclear Information System (INIS)

Ashry, O.M.

2012-01-01

The universality of aging implies that its cause is basically the same in all species. A free radical hypothesis of aging has been proposed that the free radicals produced during normal metabolism of the cell over time damage DNA and other macromolecules leading to degenerative diseases, malignancies, and eventual death of vital cells which in turn causes aging and death of the organism. This hypothesis is supported by several observations. Radiation produces its biologic effect through free radical formation and causes premature aging. Second, the age pigment lipo fuscin is associated with lipid peroxidation. The hypothesis that oxygen radicals play a role in aging is also supported by the observation that, in general, long-lived species produce less endogenous free oxygen radicals because of their lower metabolic rate. Long-lived animals also have more superoxide dismutase than do their short-lived counterparts, and animal species with the longest lifespan have the highest levels of superoxide dismutase. Oxidative DNA damage is rapidly and effectively repaired. It has been estimated that there are several thousand oxidative DNA damage sites in a human cell every day, and the majority of these are repaired. However, a small fraction of unrepaired lesions could cause permanent changes in DNA and might be a major contributor to aging and cancer. A consequence of the free radical hypothesis of aging is the idea that free radical scavenging agents might be used to prevent aging. (author)

Antioxidant and Anti-Adipogenic Activities of Trapa japonica Shell Extract Cultivated in Korea

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Lee, DooJin; Lee, Ok-Hwan; Choi, Geunpyo; Kim, Jong Dai

2017-01-01

Trapa japonica shell contains phenolic compounds such as tannins. Studies regarding the antioxidant and anti-adipogenic effects of Trapa japonica shell cultivated in Korea are still unclear. Antioxidant and anti-adipogenic activities were measured by in vitro assays such as 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity, 2,2′-azinobis( 3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity, ferric reducing ability of plasma assay, reducing power, superoxide dismutase-like activity, and iron chelating ability in 3T3-L1 cells. We also measured the total phenol and flavonoids contents (TPC and TFC, respectively) in Trapa japonica shell extract. Our results show that TPC and TFC of Trapa japonica shell extract were 157.7±0.70 mg gallic acid equivalents/g and 25.0±1.95 mg quercetin equivalents/g, respectively. Trapa japonica shell extract showed strong antioxidant activities in a dose-dependent manner in DPPH and ABTS radical scavenging activities and other methods. Especially, the whole antioxidant activity test of Trapa japonica shell extract exhibited higher levels than that of butylated hydroxytoluene as a positive control. Furthermore, Trapa japonica shell extract inhibited lipid accumulation and reactive oxygen species production during the differentiation of 3T3-L1 preadipocytes. Trapa japonica shell extract possessed a significant antioxidant and anti-adipogenic property, which suggests its potential as a natural functional food ingredient. PMID:29333386

Extraction optimization of exopolysaccharide produced by Pleurotus ...

African Journals Online (AJOL)

... EPS showed that the inhibition effects of EPS at a dosage of 4 g/l on superoxide anion and hydroxyl radicals were 70.53 ± 3.27% and 40.59 ± 2.81%, respectively and the reducing power was 0.42 ± 0.02 (absorbance at 700 nm). The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase ...

Analysis and characterisation of phytochemicals in mulberry (Morus alba L.) fruits grown in Vojvodina, North Serbia.

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Natić, Maja M; Dabić, Dragana Č; Papetti, Adele; Fotirić Akšić, Milica M; Ognjanov, Vladislav; Ljubojević, Mirjana; Tešić, Živoslav Lj

2015-03-15

In this study, the polyphenolic profile of 11 Morus alba fruits grown in the Vojvodina region was investigated. Ultra high performance liquid chromatography (UHPLC) coupled with Linear Trap Quadrupole and OrbiTrap mass analyzer, and UHPLC coupled with a diode array detector and a triple-quadrupole mass spectrometer were used for the identification and quantification of the polyphenols, respectively. A total of 14 hydroxycinnamic acid esters, 13 flavonol glycosides, and 14 anthocyanins were identified in the extracts with different distributions and contents according to the sampling. The total phenolic content ranged from 43.84 to 326.29 mg GAE/100g frozen fruit. The radical scavenging capacity (50.18-86.79%), metal chelating ability (0.21-8.15%), ferric ion reducing power (0.03-38.45 μM ascorbic acid) and superoxide anion radical scavenging activity (16.53-62.83%) were assessed. The findings indicated that mulberry polyphenolics may act as potent superoxide anion radical scavengers and reducing agents. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ethylbenzene induces microsomal oxygen free radical generation: antibody-directed characterization of the responsible cytochrome P450 enzymes.

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Serron, S C; Dwivedi, N; Backes, W L

2000-05-01

Small aromatic hydrocarbons cause changes in oxidative metabolism by modulating the levels of cytochrome P450 enzymes, with the changes in these enzymes being responsible for qualitative changes in aromatic hydrocarbon metabolism. The goal of this study was to determine if exposure to the small alkylbenzene ethylbenzene (EB) leads to an increase in hepatic free radical production. Male F344 rats were treated with ip injections of EB (10 mmol/kg) and compared to corn oil controls. Hepatic free radical production was examined by measuring the conversion of 2',7'-dichlorofluorescin diacetate (DCFH-DA) to its fluorescent product 2',7'-dichlorofluorescein (DCF). A significant elevation of fluorescent DCF production was observed after treatment with EB, despite the lack of effect on overall cytochrome P450 levels. This process was shown to be inhibitable by metyrapone, an inhibitor of P450. DCF production was also inhibited by catalase, suggesting that hydrogen peroxide (H(2)O(2)) is one of the reactive oxygen intermediates involved in EB-mediated reactive oxygen species (ROS) formation. Interestingly, superoxide dismutase (SOD) did not inhibit DCF production in corn oil-treated rats but was an effective inhibitor in the EB-treated groups. In an effort to determine if the increase in ROS production was related to changes in specific P450 enzymes, DCF production was measured in the presence of anti-CYP2B, anti-CYP2C11, anti-CYP2E1, and anti-CYP3A2 inhibitory antibodies. Anti-CYP2B antibodies inhibited DCF production in EB-treated, but not corn oil groups, which is consistent with the low constitutive levels of this enzyme and its induction by EB. The data also demonstrate that CYP2B contributes to ROS production. Anti-CYP2C11 did not influence DCF production in either group. ROS formation in corn oil-treated rats as well as in ethylbenzene-treated rats was also inhibited with antibodies to anti-CYP2E1 and anti-CYP3A2. These results suggest that CYP2C11 does not appear to

Quantitative detection of plasma-generated radicals in liquids by electron paramagnetic resonance spectroscopy

International Nuclear Information System (INIS)

Tresp, H; Hammer, M U; Winter, J; Reuter, S; Weltmann, K-D

2013-01-01

In this paper the qualitative and quantitative detection of oxygen radicals in liquids after plasma treatment with an atmospheric pressure argon plasma jet by electron paramagnetic resonance spectroscopy is investigated. Absolute values for · OH and O 2 ·- radical concentration and their net production rate in plasma-treated liquids are determined without the use of additional scavenging chemicals such as superoxide dismutase (SOD) or mannitol (D-MAN). The main oxygen-centred radical generation in PBS was found to originate from the superoxide radical. It is shown that hidden parameters such as the manufacturer of chemical components could have a big influence on the comparability and reproducibility of the results. Finally, the effect of a shielding gas device for the investigated plasma jet with a shielding gas composition of varying oxygen-to-nitrogen ratio on radical generation after plasma treatment of phosphate-buffered saline solution was investigated. (paper)

Free radical-scavenging delta-lactones from Boletus calopus.

Science.gov (United States)

Kim, Jin-Woo; Yoo, Ick-Dong; Kim, Won-Gon

2006-12-01

The methanol extracts from the fruiting body of the mushroom Boletus calopus showed free radical-scavenging activity. Bioactivity-guided fractionation of the methanol extracts led to a new hydroxylated calopin named calopin B, along with the known delta-lactones calopin and cyclocalopin A. The structure of the new calopin analogue was elucidated by spectroscopic methods. All compounds showed potent free radical-scavenging activity against superoxide, DPPH, and ABTS radicals with IC (50) values of 1.2 - 5.4 microg/mL.

Superoxide dismutase 1-mediated production of ethanol- and DNA-derived radicals in yeasts challenged with hydrogen peroxide: molecular insights into the genome instability of peroxiredoxin-null strains.

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Ogusucu, Renata; Rettori, Daniel; Netto, Luis E S; Augusto, Ohara

2009-02-27

Peroxiredoxins are receiving increasing attention as defenders against oxidative damage and sensors of hydrogen peroxide-mediated signaling events. In the yeast Saccharomyces cerevisiae, deletion of one or more isoforms of the peroxiredoxins is not lethal but compromises genome stability by mechanisms that remain under scrutiny. Here, we show that cytosolic peroxiredoxin-null cells (tsa1Deltatsa2Delta) are more resistant to hydrogen peroxide than wild-type (WT) cells and consume it faster under fermentative conditions. Also, tsa1Deltatsa2Delta cells produced higher yields of the 1-hydroxyethyl radical from oxidation of the glucose metabolite ethanol, as proved by spin-trapping experiments. A major role for Fenton chemistry in radical formation was excluded by comparing WT and tsa1Deltatsa2Delta cells with respect to their levels of total and chelatable metal ions and of radical produced in the presence of chelators. The main route for 1-hydroxyethyl radical formation was ascribed to the peroxidase activity of Cu,Zn-superoxide dismutase (Sod1), whose expression and activity increased approximately 5- and 2-fold, respectively, in tsa1Deltatsa2Delta compared with WT cells. Accordingly, overexpression of human Sod1 in WT yeasts led to increased 1-hydroxyethyl radical production. Relevantly, tsa1Deltatsa2Delta cells challenged with hydrogen peroxide contained higher levels of DNA-derived radicals and adducts as monitored by immuno-spin trapping and incorporation of (14)C from glucose into DNA, respectively. The results indicate that part of hydrogen peroxide consumption by tsa1Deltatsa2Delta cells is mediated by induced Sod1, which oxidizes ethanol to the 1-hydroxyethyl radical, which, in turn, leads to increased DNA damage. Overall, our studies provide a pathway to account for the hypermutability of peroxiredoxin-null strains.

Targeting the superoxide/nitric oxide ratio by L-arginine and SOD mimic in diabetic rat skin.

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Jankovic, Aleksandra; Ferreri, Carla; Filipovic, Milos; Ivanovic-Burmazovic, Ivana; Stancic, Ana; Otasevic, Vesna; Korac, Aleksandra; Buzadzic, Biljana; Korac, Bato

2016-11-01

Setting the correct ratio of superoxide anion (O 2 •- ) and nitric oxide ( • NO) radicals seems to be crucial in restoring disrupted redox signaling in diabetic skin and improvement of • NO physiological action for prevention and treatment of skin injuries in diabetes. In this study we examined the effects of L-arginine and manganese(II)-pentaazamacrocyclic superoxide dismutase (SOD) mimic - M40403 in diabetic rat skin. Following induction of diabetes by alloxan (blood glucose level ≥12 mMol l  -1 ) non-diabetic and diabetic male Mill Hill hybrid hooded rats were divided into three subgroups: (i) control, and receiving: (ii) L-arginine, (iii) M40403. Treatment of diabetic animals started after diabetes induction and lasted for 7 days. Compared to control, lower cutaneous immuno-expression of endothelial NO synthase (eNOS), heme oxygenase 1 (HO1), manganese SOD (MnSOD) and glutathione peroxidase (GSH-Px), in parallel with increased NFE2-related factor 2 (Nrf2) and nitrotyrosine levels characterized diabetic skin. L-arginine and M40403 treatments normalized alloxan-induced increase in nitrotyrosine. This was accompanied by the improvement/restitution of eNOS and HO1 or MnSOD and GSH-Px protein expression levels in diabetic skin following L-arginine, i.e. SOD mimic treatments, respectively. The results indicate that L-arginine and M40403 stabilize redox balance in diabetic skin and suggest the underlying molecular mechanisms. Restitution of skin redox balance by L-arginine and M40403 may represent an effective strategy to ameliorate therapy of diabetic skin.

The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice.

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Miyazawa, Masaki; Ishii, Takamasa; Yasuda, Kayo; Noda, Setsuko; Onouchi, Hiromi; Hartman, Philip S; Ishii, Naoaki

2009-01-01

Much attention has been focused on the mitochondrial superoxide anion (O2(-)), which is also a critical free radial produced by ionizing radiation. The specific role of the mitochondrial O2(-) on physiological aging in mammals is still unclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O2(-) is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O2(-)relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O2(-) production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O2(-) levels. Mitochondrial O2(-) production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O2(-) production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O2(-) production has high organ specificity, and oxidative damage by O2(-) from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O2(-) from mitochondria plays a core role in physiological aging.

Treating infected diabetic wounds with superoxidized water as anti-septic agent: a preliminary experience

International Nuclear Information System (INIS)

Hadi, S.F.; Khaliq, T.; Zubair, M.; Saaiq, M.; Sikandar, I.

2007-01-01

To evaluate the effectiveness of superoxidized water (MicrocynTM) in diabetic patients with different wounds. One hundred known diabetic patients were enrolled. Half were randomized to the intervention group (those whose wounds were managed with superoxidized water) and half to the control group (whose wounds were treated with normal saline) using a table of random numbers. The two groups were matched for age, gender, duration of diabetes and category of wound. All patients received appropriate surgical treatment for their wounds as required. Local wound treatment was carried out daily using superoxidized water soaked gauzes on twice daily basis in the intervention group and normal saline in the control group. The treatment was continued until wound healing. The main outcome measures were duration of hospital stay, downgrading of the wound category, wound healing time and need for interventions such as amputation. Statistically significant differences were found in favour of the superoxidized water group with respect to duration of hospital stay, downgrading of the wound category and wound healing time. Although the initial results of employing superoxidized water for the management of infected diabetic wounds are encouraging, further multicentre clinical trials are warranted before this antiseptic is recommended for general use. It may offer an economical alternative to other expensive antiseptics with positive impact on the prevailing infection rates, patient outcomes and patient satisfaction. (author)

The potential of the superoxide dismutase inhibitor, diethyldithiocarbamate as an adjuvant to radiotherapy

International Nuclear Information System (INIS)

Kent, C.

1990-10-01

Oxygen has the potential to be toxic to biologic systems. This toxicity is not due to oxygen itself, but due to the production of oxygen radicals. One of these potentially toxic radicals, superoxide, can be generated as a result of ionizing radiation, and if not adequately removed can proceed to cause cell damage. Superoxide dismutase (SOD) is one of the key enzymes involved in the defence against oxygen toxicity. SOD activity can be inhibited by diethyldithiocarbamate (DDC), a powerful copper chelator. If inhibition of SOD by DDC increases the lifetime and effectiveness of radiation induced superoxide, it follows that the potential exists for DDC to enhance the effect of radiation. DDC is however also a thiol compound, and thus may act as a radioprotector by modifying tissue oxygenation status or by free radical scavenging. The inhibition of superoxide dismutase by diethyldithiocarbamate in order to sensitize tumours to ionizing radiation was studied. The use of DDC as an inhibitor of SOD has however meant that any sensitization resulting from SOD inhibition could be masked by a radioprotective effect by DDC. The inhibition of SOD by DDC was confirmed in a murine rhabdomyosarcoma, and this inhibition can be maintained for up to twenty-four hours after DDC administration. It was shown that DDC could act as both a radiosensitizer and as a radioprotector in the same experiment. The dominant action of DDC was found to be dependent on the time allowed between DDC administration and irradiation. The time modulation effect of DDC was shown in larger tumours, rather than smaller tumours, which could indicate that tumour oxygenation is an important criterion in determining the response to radiation of DDC treated cells. Some caution should be exercised when DDC is put forward as either a radiosensitizer or a radioprotector in the clinic, but DDC may have potential as a thermosensitizer. 37 figs., 23 tabs., 208 refs

The superoxide scavenger TEMPOL induces urokinase receptor (uPAR expression in human prostate cancer cells

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Francis Joseph

2006-06-01

Full Text Available Abstract There is little understanding of the effect that reactive oxygen metabolites have on cellular behavior during the processes of invasion and metastasis. These oxygen metabolites could interact with a number of targets modulating their function such as enzymes involved in basement membrane dissolution, adhesion molecules involved in motility or receptors involved in proliferation. We investigated the effect of increased scavenging of superoxide anions on the expression of the urokinase receptor (uPAR in PC-3M human prostate cancer cells. Urokinase receptor is a GPI-linked cell surface molecule which mediates multiple functions including adhesion, proliferation and pericellular proteolysis. Addition of the superoxide scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPOL to PC-3M cultures stimulated expression of uPAR protein peaking between 48 and 72 hours. Cell surface expression of the uPAR was also increased. Surprisingly, uPAR transcript levels increased only slightly and this mild increase did not coincide with the striking degree of protein increase. This disparity indicates that the TEMPOL effect on uPAR occurs through a post-transcriptional mechanism. TEMPOL presence in PC-3M cultures reduced intracellular superoxide-type species by 75% as assayed by NBT dye conversion; however this reduction significantly diminished within hours following TEMPOL removal. The time gap between TEMPOL treatment and peak uPAR protein expression suggests that reduction of reactive oxygen metabolites in prostate cancer cells initiates a multistep pathway which requires several hours to culminate in uPAR induction. These findings reveal a novel pathway for uPAR regulation involving reactive oxygens such as superoxide anion.

Free radical scavenging activities of yellow gentian (Gentiana lutea L.) measured by electron spin resonance.

Science.gov (United States)

Kusar, A; Zupancic, A; Sentjurc, M; Baricevic, D

2006-10-01

Yellow gentian (Gentiana lutea L.) is a herbal species with a long-term use in traditional medicine due to its digestive and stomachic properties. This paper presents an investigation of the free radical scavenging activity of methanolic extracts of yellow gentian leaves and roots in two different systems using electron spin resonance (ESR) spectrometry. Assays were based on the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the superoxide radicals (O2*-) generated by the xanthine/xanthine oxidase (X/XO) system. The results of gentian methanolic extracts were compared with the antioxidant capacity of synthetic antioxidant butylated hydroxyanisole (BHA). This study proves that yellow gentian leaves and roots exhibit considerable antioxidant properties, expressed either by their capability to scavenge DPPH or superoxide radicals.

Investigations of structure, bonding, and reactions of radiation-induced free radicals in the solid state using electron spin resonance spectroscopy

International Nuclear Information System (INIS)

Hudson, R.L.

1978-01-01

Electron spin resonance spectroscopy (ESR) has been used to study the structure, bonding, and reactions of several types of free radicals produced by γ irradiation of solids at 77K. Well-defined spectral patterns and the use of photolysis and annealing treatments assisted the analyses and interpretations. The radical anion BF 3 - was generated and identified unequivocally in a matrix of tetramethylsilane at 77K. Both the ESR data and theoretical calculations support a pyramidal structure with a bond angle of about 110 0 . The present experiments showed that BF 3 - has ESR parameters consistent with those of the isoelectronic radicals CF 3 , NF 3 + , and F 2 NO. γ irradiation of polycrystalline trimethyl borate at 77K gave an ESR spectrum which was assigned to the dimer radical anion [(MeO) 3 B.B(OMe) 3 ] - . Radical anions of dialkyl carbonates were observed for the first time and found to undergo a β-scission reaction to produce alkyl radicals. This free radical reaction is unusual in that it proceeds both thermally and photochemically. For the dimethyl carbonate radical anion, 13 C parameters were obtained from a 13 C enriched sample. The photolysis of trapped radicals in γ irradiated carboxylic esters, RC(O)OR', was studied by ESR spectroscopy and two different reactions were characterized. Two hypervalent silicon radical anions were prepared and examined in SI(OCH 3 ) 4 . The results of the present work thus represent the first complete sets of data on the silicon 3s and 3p spin densities for such species. The first PL 3 - radical anion was prepared by the γ irradiation of crystalline trimethylphosphite, and identified through its photolysis reactions and from the results of radiation chemical experiments

Antioxidant and Anti-Inflammatory Properties of Longan (Dimocarpus longan Lour. Pericarp

Directory of Open Access Journals (Sweden)

Guan-Jhong Huang

2012-01-01

Full Text Available This study examined the antioxidant and anti-inflammatory activities of the water extract of longan pericarp (WLP. The results showed that WLP exhibited radical scavenging, reducing activity and liposome protection activity. In addition, WLP also inhibited lipopolysaccharide (LPS-induced nitric oxide (NO production in macrophages. Further, administration of WLP, in the range of 100–400 mg/kg, showed a concentration-dependent inhibition on paw edema development following carrageenan (Carr treatment in mice. The anti-inflammatory effects of WLP may be related to NO and tumor necrosis factor (TNF-α suppression and associated with the increase in the activities of antioxidant enzymes, including catalase, superoxide dismutase, and glutathione peroxidase. Overall, the results showed that WLP might serve as a natural antioxidant and inflammatory inhibitor.

Carp head kidney leukocytes display different patterns of oxygen radical production after stimulation with PAMPs and DAMPs

DEFF Research Database (Denmark)

Jiménez, Natalia Ivonne Vera; Nielsen, Michael Engelbrecht

2013-01-01

. Consistent with a pathogen eradication strategy, ROS responses to PAMP stimulation (β-glucan) was fast, vigorous and highly dominated by production of superoxide anion. In contrast, stimulation with DAMPs led to a slow, subtle but long-lasting production of oxygen radicals dominated by hydrogen peroxide....... Using an in vitro model of scratch-wounded CCB fibroblast cell cultures and a novel PhotoID proliferation assay, stimulation with low and continuous levels of hydrogen peroxide (5μM) led to a slight increase in the percentage of wound recovery and thus promoted wound closure. In contrast, high doses...... and thereby potential tissue damage. Direct in vitro stimulation with β-glucans did not impact fibroblast scratch-wound recovery, which further suggests that interaction with tissue-resident leukocytes or other components of the fish immune system are required to induce fibroblast proliferation and thus...

E. s. r. of free radicals in irradiated uracil-. beta. -D-arabinofuranoside

Energy Technology Data Exchange (ETDEWEB)

Bergene, R [Oslo Univ. (Norway). Fysisk Institutt; Vaughan, R A

1976-02-01

Electron-spin-resonance measurements have been made on single crystals of uracil-..beta..-D-arabinofuranoside, which were irradiated by 4.0 MeV electrons at 77 K. At low temperatures, two radicals have been identified, one attributed to a hydrogen abstraction of 05' in the sugar moiety and the other to a radical anion located on the pyrimidine ring. The former was very unstable and seemed to act as a precursor to other unidentified radical species stable at 77 K. At room temperature, the main resonance was due to hydrogen addition to C5 and was probably produced by protonation of the anion. This same radical was also produced by irradiation at room temperature.

Antioxidant and Anti-Inflammatory Activities of Unexplored Brazilian Native Fruits

Science.gov (United States)

Infante, Juliana; Rosalen, Pedro Luiz; Lazarini, Josy Goldoni; Franchin, Marcelo; de Alencar, Severino Matias

2016-01-01

Brazilian native fruits are unmatched in their variety, but a poorly explored resource for the development of food and pharmaceutical products. The aim of this study was to evaluate the phenolic composition as well as the antioxidant and anti-inflammatory activities of the extracts of leaves, seeds, and pulp of four Brazilian native fruits (Eugenia leitonii, Eugenia involucrata, Eugenia brasiliensis, and Eugenia myrcianthes). GC—MS analyses of the ethanolic extracts showed the presence of epicatechin and gallic acid as the major compounds in these fruits. Antioxidant activity was measured using synthetic DPPH free-radical scavenging, β-carotene bleaching assay, and reactive oxygen species (ROO·, O2·−, and HOCl). The fruit extracts also exhibited antioxidant effect against biologically relevant radicals such as peroxyl, superoxide, and hypochlorous acid. In general, the pulps were the fruit fractions that exhibited the lowest antioxidant activities, whereas the leaves showed the highest ones. The anti-inflammatory activity was assessed in an in vivo model using the carrageenan-induced neutrophil migration assay, which evaluates the inflammatory response in the acute phase. The pulp, seeds, and leaves of these fruits reduced the neutrophil influx by 40% to 64%. Based on these results, we suggest that the anti-inflammatory activity of these native fruits is related to the modulation of neutrophil migration, through the inhibition of cytokines, chemokines, and adhesion molecules, as well as to the antioxidant action of their ethanolic extracts in scavenging the free-radicals released by neutrophils. Therefore, these native fruits can be useful to produce food additives and functional foods. PMID:27050817

The Superoxide Reductase from the Early Diverging Eukaryote Giardia Intestinalis

International Nuclear Information System (INIS)

Cabelli, D.E.; Testa, F.; Mastronicola, D.; Bordi, E.; Pucillo, L.P.; Sarti, P.; Saraiva, L.M.; Giuffre, A.; Teixeira, M.

2011-01-01

Unlike superoxide dismutases (SODs), superoxidereductases (SORs) eliminate superoxide anion (O 2 # sm b ullet# - ) not through its dismutation, but via reduction to hydrogen peroxide (H 2 O 2 ) in the presence of an electron donor. The microaerobic protist Giardia intestinalis, responsible for a common intestinal disease in humans, though lacking SOD and other canonical reactive oxygen species-detoxifying systems, is among the very few eukaryotes encoding a SOR yet identified. In this study, the recombinant SOR from Giardia (SOR Gi ) was purified and characterized by pulse radiolysis and stopped-flow spectrophotometry. The protein, isolated in the reduced state, after oxidation by superoxide or hexachloroiridate(IV), yields a resting species (T final ) with Fe 3+ ligated to glutamate or hydroxide depending on pH (apparent pK a = 8.7). Although showing negligible SOD activity, reduced SOR Gi reacts with O 2 # sm b ullet# - with a pH-independent second-order rate constant k 1 = 1.0 x 10 9 M -1 s -1 and yields the ferric-(hydro)peroxo intermediate T 1 ; this in turn rapidly decays to the T final state with pH-dependent rates, without populating other detectable intermediates. Immunoblotting assays show that SOR Gi is expressed in the disease-causing trophozoite of Giardia. We propose that the superoxide-scavenging activity of SOR in Giardia may promote the survival of this air-sensitive parasite in the fairly aerobic proximal human small intestine during infection.

Enantioselective radical addition/trapping reactions with alpha,beta-disubstituted unsaturated imides. Synthesis of anti-propionate aldols.

Science.gov (United States)

Sibi, Mukund P; Petrovic, Goran; Zimmerman, Jake

2005-03-02

This manuscript describes a highly diastereo- and enantioselective intermolecular radical addition/hydrogen atom transfer to alpha,beta-disubstituted enoates. Additionally, we show that anti-propionate aldol-like products can be easily prepared from alpha-methyl-beta-acyloxyenoates in good yields and high diastereo- and enantioselectivities.

Fast Resonance Raman Spectroscopy of Short-Lived Radicals

DEFF Research Database (Denmark)

Pagsberg, Palle Bjørn; Wilbrandt, Robert Walter; Hansen, Karina Benthin

1976-01-01

We report the first application of pulsed resonance Raman spectroscopy to the study of short-lived free radicals produced by pulse radiolysis. A single pulse from a flash-lamp pumped tunable dye laser is used to excite the resonance Raman spectrum of the p-terphenyl anion radical with an initial...

Cultured rat and purified human Pneumocystis carinii stimulate intra- but not extracellular free radical production in human neutrophils

DEFF Research Database (Denmark)

Jensen, T; Aliouat, E M; Lundgren, B

1998-01-01

The production of free radicals in human neutrophils was studied in both Pneumocystis carinii derived from cultures of L2 rat lung epithelial-like cells and Pneumocystis carinii purified from human lung. Using the cytochrome C technique, which selectively measured extracellular superoxide...... generation, hardly any free radical production was observed after stimulation with cultured rat-derived P. carinii. A chemiluminescence technique, which separately measured intra- and extracellular free radical production, was subsequently employed to differentiate the free radical generation....... It was established that 1) P. carinii stimulated intra- but not extracellular free radical production in human neutrophils, 2) opsonized cultured rat-derived P. carinii stimulated human neutrophils to a strong intracellular response of superoxide production, and 3) opsonized P. carinii, purified from human lung also...

Hyperoxia exposure induced hormesis decreases mitochondrial superoxide radical levels via Ins/IGF-1 signaling pathway in a long-lived age-1 mutant of Caenorhabditis elegans

International Nuclear Information System (INIS)

Yanase, Sumino; Ishii, Naoaki

2008-01-01

The hormetic effect, which extends the lifespan by various stressors, has been confirmed in Caenorhabditis elegans (C. elegans). We have previously reported that oxidative stress resistance in a long-lived mutant age-1 is associated with the hormesis. In the age-1 allele, which activates an insulin/insulin-like growth factor-1 (Ins/IGF-1) signaling pathway, the superoxide dismutase (SOD) and catalase activities increased during normal aging. We now demonstrate changes in the mitochondrial superoxide radical (O 2 - ) levels of the hormetic conditioned age-related strains. The O 2 - levels in age-1 strain significantly decreased after intermittent hyperoxia exposure. On the other hand, this phenomenon was not observed in a daf-16 null mutant. This hormesis-dependent reduction of the O 2 - levels was observed even if the mitochondrial Mn-SOD was experimentally reduced. Therefore, it is indicated that the hormesis is mediated by events that suppress the mitochondrial O 2 - production. Moreover, some SOD gene expressions in the hormetic conditioned age-1 mutant were induced over steady state messenger ribonucleic acid (mRNA) levels. These data suggest that oxidative stress-inducible hormesis is associated with a reduction of the mitochondrial O 2 - production by activation of the antioxidant system via the Ins/IGF-1 signaling pathway. (author)

Flow Injection Photosensitized Chemiluminescence of Luminol with Cu(II-Rose Bengal: Mechanistic Approach and Vitamin A and C Determination

Directory of Open Access Journals (Sweden)

Muhammad Asgher

2014-01-01

Full Text Available Rose Bengal photosensitized flow injection chemiluminescence method is reported using luminol-Cu(II for the determination of vitamins A and C in pharmaceutical formulations. The reaction is based on the enhancement effect of analyte in the production of anion radicals of Rose Bengal (RB•− which rapidly interact with dissolved oxygen and generate superoxide anions radicals (O2•− and hydrogen peroxide (H2O2. Highly reactive hydroxyl radicals (•OH were produced via dismutation of H2O2 by catalyst (Cu2+. The generated superoxide anions radicals and hydroxyl radicals thus oxidize luminol in alkaline medium to generate strong chemiluminescence. The limit of detection (3s of the blank, n=6 of vitamins A and C and RB was found to be 0.008, 0.005, and 0.05 μg mL−1, respectively. The sample throughput of 70 h−1 for vitamins A and C and 30 h−1 for RB was found. Calibration curve was linear in the range of 0.05–15, 0.01–20, and 0.1–50 μg mL−1 for vitamins A and C and RB, respectively, with relative standard deviations (RSDs; n=3 in the range 1.6–3.6%. The method was successfully applied to pharmaceutical formulations and the results obtained were in good agreement with the labeled values.

Free radicals in dicarboxylic acids: an e.s.r. study of radical conversions in γ-irradiated single crystals of glutaric acid and glutaric-2,2,4,4-d4 acid

International Nuclear Information System (INIS)

Bergene, R.; Minegishi, A.; Riesz, P.

1980-01-01

The γ-radiation-induced free radicals in single crystals of glutaric acid and glutaric-2,2,4,4-d 4 acid were studied in the temperature range 77-300 K by e.s.r. techniques. At 77 K the decarboxylation radical and the anion are stabilized. At higher temperatures the decarboxylation radical is found to be converted into a hydrogen abstraction radical with an activation energy of 6.3 +- 0.5 kcal/mole for the non-deuterated crystal. This radical is stable at room temperature. The anion seems to be converted to a unidentified intermediate radical which in turn is converted to the σ-acyl radical. An analysis of the g-value anisotropy and of the 13 C hyperfine splitting variation for this radical in the deuterated crystal is consistent with the assigned radical structure. By heat treatment the σ-acyl radical is converted to another form of the hydrogen abstraction radical with an activation energy of 9.6 +- 0.6 kcal/mole in the deuterated crystal. U.V.-light (lambda= 254 nm) transforms one of the room temperature radicals into the other. (author)

Resistance of Lactobacillus plantarum KCTC 3099 from Kimchi to oxidative stress.

Science.gov (United States)

Lee, Jeongmin; Hwang, Kwon-Tack; Heo, Moon-Soo; Lee, Jun-Haeng; Park, Kun-Young

2005-01-01

The antioxidative capacity of two lactic acid bacteria isolated from Kimchi, a Korean fermented food, was evaluated by measuring the resistance to reactive oxygen species (ROS) and compared with that of Lactobacillus rhamnosus GG as a positive control. Both intact cells and cell-free extracts of Lactobacillus plantarum KCTC 3099 exhibited higher antioxidative activity in inhibiting lipid peroxidation among the strains evaluated with an inhibitory level of 38.6% and 48.5%, respectively. To evaluate the resistance of the two lactic acid bacteria to ROS, we tested their survival in the presence of 1 mM hydrogen peroxide, 0.4 mM hydroxyl radicals, and superoxide anions induced by 10 mM paraquat. L. plantarum KCTC 3099 was viable even after 8 hours in the presence of both 1 mM hydrogen peroxide and 0.4 mM hydroxyl radicals. Moreover, the survival of L. plantarum KCTC 3099 was not affected by superoxide anions generated by using paraquat, indicating that it has resistance to superoxide anions. To define the antioxidative mechanism, superoxide dismutase (SOD) and metal ion chelating activities were determined. L. plantarum KCTC 3099 presented little SOD activity, but had the higher level of chelating activity for both Fe2+ and Cu2+ metal ions at 13.6 ppm and 23.9 ppm, respectively. These results suggested that the antioxidative capacity of L. plantarum KCTC 3099 is apparently caused by chelating metal ions rather than by SOD activation.

Evidence for radical anion formation during liquid secondary ion mass spectrometry analysis of oligonucleotides and synthetic oligomeric analogues: a deconvolution algorithm for molecular ion region clusters.

Science.gov (United States)

Laramée, J A; Arbogast, B; Deinzer, M L

1989-10-01

It is shown that one-electron reduction is a common process that occurs in negative ion liquid secondary ion mass spectrometry (LSIMS) of oligonucleotides and synthetic oligonucleosides and that this process is in competition with proton loss. Deconvolution of the molecular anion cluster reveals contributions from (M-2H).-, (M-H)-, M.-, and (M + H)-. A model based on these ionic species gives excellent agreement with the experimental data. A correlation between the concentration of species arising via one-electron reduction [M.- and (M + H)-] and the electron affinity of the matrix has been demonstrated. The relative intensity of M.- is mass-dependent; this is rationalized on the basis of base-stacking. Base sequence ion formation is theorized to arise from M.- radical anion among other possible pathways.

EPR Spectroscopy of Radical Ions of a 2,3-Diamino-1,4-naphthoquinone Derivative.

Science.gov (United States)

Tarábek, Ján; Wen, Jin; Dron, Paul I; Pospíšil, Lubomír; Michl, Josef

2018-05-18

We report the electron paramagnetic resonance spectra of the radical cation and radical anion of 1,2,2,3-tetramethyl-2,3-dihydro-1 H-naphtho[2,3- d]imidazole-4,9-dione (1) and its doubly 13 C labeled analogue 2, of interest for singlet fission. The hyperfine coupling constants are in excellent agreement with density functional theory calculations and establish the structures beyond doubt. Unlike the radical cation 1 •+ , the radical anion 1 •- and its parent 1 have pyramidalized nitrogen atoms and inequivalent methyl groups 15 and 16, in agreement with the calculations. The distinction is particularly clear with the labeled analogue 2 •- .

cis-Thioindigo (TI) - a new ligand with accessible radical anion and dianion states. Strong magnetic coupling in the {[TI-(μ2-O),(μ-O)]Cp*Cr}2 dimers.

Science.gov (United States)

Konarev, Dmitri V; Khasanov, Salavat S; Shestakov, Alexander F; Fatalov, Alexey M; Batov, Mikhail S; Otsuka, Akihiro; Yamochi, Hideki; Kitagawa, Hiroshi; Lyubovskaya, Rimma N

2017-10-24

Reaction of decamethylchromocene (Cp* 2 Cr) with thioindigo (TI) yields a coordination complex {[TI-(μ 2 -O), (μ-O)]Cp*Cr} 2 ·C 6 H 14 (1) in which one Cp* ligand in Cp* 2 Cr is substituted by TI. TI adopts cis-conformation in 1 allowing the coordination of both carbonyl groups to chromium. Additionally, one oxygen atom of TI becomes a μ 2 -bridge for two chromium atoms to form {[TI-(μ 2 -O), (μ-O)]Cp*Cr} 2 dimers with a CrCr distance of 3.12 Å. According to magnetic data, diamagnetic TI 2- dianions and two Cr 3+ atoms with a high S = 3/2 spin state are present in a dimer allowing strong antiferromagnetic coupling between two Cr 3+ spins with an exchange interaction of -35.4 K and the decrease of molar magnetic susceptibility below 140 K. Paramagnetic TI˙ - radical anions with the S = 1/2 spin state have also been obtained and studied in crystalline {cryptand[2,2,2](Na + )}(TI˙ - ) (2) salt showing that both radical anion and dianion states are accessible for TI.

Neutrophil superoxide-anion generating capacity in chronic smoking: effect of long-term alpha-tocopherol therapy

NARCIS (Netherlands)

Tits, van L.; Waart, de F.; Hak-Lemmers, H.L.M.; Graaf, de J.; Demacker, P.N.; Stalenhoef, A.F.

2003-01-01

We investigated whether long-term alpha-tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 21 pack years of smoking) to treatment with placebo (n = 64) or alpha-tocopherol (400 IU

Reactions of inorganic free radicals with liver protecting drugs

International Nuclear Information System (INIS)

Gyoergy, I.; Foeldiak, G.; Blazovics, A.; Feher, J.

1990-01-01

Liver protecting drugs, silibinin, a flavonolignane, and the dihydroquinoline derivatives, CH 402 and MTDQ-DA, were shown to inhibit processes in which enzymatically or non-enzymatically generated free radicals were involved. Inorganic free radicals (N 3 , (SCN) 2 - , OH, Trp, CO 2 - , O 2 - ) produced by pulse radiolysis readily react with the compounds, which transform into exceptionally long-lived, unreactive transients. Time evolution of the UV and visible spectra indicate that oxidising radicals form a phenoxyl type radical from silibinin, while OH forms an adduct by attacking, simultaneously, at various sites of the molecule. Superoxide radicals reduce silibinin and oxidise CH 402 and MTDQ-DA. It is concluded that the drugs might exhibit antioxidant behavior in living systems. (author)

Ion pairing of radical ions of aromatic alkenes and alkynes studied by pulse radiolysis

International Nuclear Information System (INIS)

Yamamoto, Satoshi; Yamamoto, Yukio; Hayashi, Koichiro

1991-01-01

Pulse radiolysis of 1,2-dichloroethane solutions of trans,trans-1,4-bis(2-phenylethenyl)benzene and 1,4-bis(2-phenylethynyl)benzene was undertaken in the presence of Bu 4 NPF 6 (Bu=butyl) to investigate the effect of ion pairing of the solute radical cations with PF 6 - . It was also undertaken for the tetrahydrofuran solutions of the above compounds in the presence of Bu 4 NPF 6 and NaBPh 4 , where the solute radical anions are generated and form ion pairs with Bu 4 N + and Na + . The decay of the radical ions, which is due to neutralization, is retarded by the ion pairing. The rate constants for the neutralization reactions in the free-ion and ion-paired states were determined. Also presented are the data for the radical ions of trans-stilbene, diphenylacetylene, trans,trans-1,4-diphenyl-1,3-butadiene, and diphenylbutadiene. The radical ions of the aromatic alkynes are less stabilized by the ion pairing than those of the aromatic alkenes having the same carbon skeletons probably because of more extensive charge delocalization of the former radical ions. Spectral shifts to shorter wavelengths caused by the ion pairing are appreciable for the radical anions. Dependence of the spectral shifts on the size of the radical anions is described. (author)

Hypolipidemic and antioxidant activity of mountain celery (Cryptotaenia japonica Hassk) seed essential oils.

Science.gov (United States)

Cheng, Ming-Ching; Lin, Li-Yun; Yu, Tung-Hsi; Peng, Robert Y

2008-06-11

Mountain celery seed essential oils (MC-E) contained 109 compounds, including mainly nine kinds of monoterpenoids, 31 kinds of of sesquiterpenoids, and 22 kinds of alcohols. A successive gel column adsorption with solvent fractionation yielded four fractionates. The pentane fractionate revealed potent hypolipidemic but poor antioxidant activities. The ether fractionate exhibited strong hypolipidemic activity in addition to excellent 1,1-diphenyl-2-picrylhydrazyl free radical- and superoxide anion-scavenging capabilities. The third acetone fractionate only showed moderate superoxide anion-scavenging activity. Finally, the fourth methanol fractionate having a rather high content of gamma-selinene, 2-methylpropanal, and Z-9-octadecenamide uniquely revealed very strong superoxide anion-scavenging capability. All MC diets except the MC-E-added diet simultaneously exhibited both significant hypolipidemic and high-density lipoprotein-cholesterol (HDL-C)-elevating capabilities. However, all diets totally failed to affect the hepatic phospholipid levels. Conclusively, the MC-E can be fractionated by such a separation technology to produce products uniquely possessing hypolipidemic and HDL-C-elevating activities.

DFT Study on Molecular Structures and ROS Scavenging Mechanisms of Novel Antioxidants from Lespedeza Virgata

Science.gov (United States)

Li, Min-jie; Zhang, Liang-miao; Liu, Wei-xia; Lu, Wen-cong

2011-04-01

The molecular structure and radical scavenging activity of three novel antioxidants from Lespedeza Virgata, lespedezavirgatol, lespedezavirgatal, and lespedezacoumestan, have been studied using density functional theory with the B3LYP and BhandHLYP methods. The optimized geometries of neutral, radical cation, radical and anion forms were obtained at the B3LYP/6-31G(d) level, in which it was found that all the most stable conformations contain intramolecular hydrogen bonds. The same results were obtained from the MP2 method. The homolytic O—H bond dissociation enthalpy and the adiabatic ionization potential of neutral and anion forms for the three new antioxidants and adiabatic electron affinity and H-atom affinity for hydroxyl radical, superoxide anion radical, and hydrogen peroxide radical were determined both in gas phase and in aqueous solution using IEF-PCM and CPCM model with UAHF or Bondi cavity. The antioxidant activities and reactive oxygen species scavenging mechanisms were then discussed, and the results obtained from different methods are consistent. Furthermore, the antioxidant activities are consistent with the experimental findings of the compounds under investigation.

Antioxidant and anti-inflammatory activities of extracts from Cassia alata, Eleusine indica, Eremomastax speciosa, Carica papaya and Polyscias fulva medicinal plants collected in Cameroon.

Science.gov (United States)

Sagnia, Bertrand; Fedeli, Donatella; Casetti, Rita; Montesano, Carla; Falcioni, Giancarlo; Colizzi, Vittorio

2014-01-01

The vast majority of the population around the world has always used medicinal plants as first source of health care to fight infectious and non infectious diseases. Most of these medicinal plants may have scientific evidence to be considered in general practice. The aim of this work was to investigate the antioxidant capacities and anti-inflammatory activities of ethanol extracts of leaves of Cassia alata, Eleusine indica, Carica papaya, Eremomastax speciosa and the stem bark of Polyscias fulva, collected in Cameroon. Chemiluminescence was used to analyze the antioxidant activities of plant extracts against hydrogen peroxide or superoxide anion. Comet assays were used to analyze the protection against antioxidant-induced DNA damage induced in white blood cells after treating with hydrogen peroxide. Flow cytometry was used to measure γδ T cells proliferation and anti-inflammatory activity of γδ T cells and of immature dendritic cells (imDC) in the presence of different concentrations of plant extracts. Ethanol extracts showed strong antioxidant properties against both hydrogen peroxide and superoxide anion. Cassia alata showed the highest antioxidant activity. The effect of plant extracts on γδ T cells and imDC was evidenced by the dose dependent reduction in TNF-α production in the presence of Cassia alata, Carica papaya, Eremomastax speciosa Eleusine indica, and Polyscias fulva. γδ T cells proliferation was affected to the greatest extent by Polyscias fulva. These results clearly show the antioxidant capacity and anti-inflammatory activities of plant extracts collected in Cameroon. These properties of leaves and stem bark extracts may contribute to the value for these plants in traditional medicine and in general medical practice.

Antioxidant and anti-inflammatory activities of extracts from Cassia alata, Eleusine indica, Eremomastax speciosa, Carica papaya and Polyscias fulva medicinal plants collected in Cameroon.

Directory of Open Access Journals (Sweden)

Bertrand Sagnia

Full Text Available BACKGROUND: The vast majority of the population around the world has always used medicinal plants as first source of health care to fight infectious and non infectious diseases. Most of these medicinal plants may have scientific evidence to be considered in general practice. OBJECTIVE: The aim of this work was to investigate the antioxidant capacities and anti-inflammatory activities of ethanol extracts of leaves of Cassia alata, Eleusine indica, Carica papaya, Eremomastax speciosa and the stem bark of Polyscias fulva, collected in Cameroon. METHODS: Chemiluminescence was used to analyze the antioxidant activities of plant extracts against hydrogen peroxide or superoxide anion. Comet assays were used to analyze the protection against antioxidant-induced DNA damage induced in white blood cells after treating with hydrogen peroxide. Flow cytometry was used to measure γδ T cells proliferation and anti-inflammatory activity of γδ T cells and of immature dendritic cells (imDC in the presence of different concentrations of plant extracts. RESULTS: Ethanol extracts showed strong antioxidant properties against both hydrogen peroxide and superoxide anion. Cassia alata showed the highest antioxidant activity. The effect of plant extracts on γδ T cells and imDC was evidenced by the dose dependent reduction in TNF-α production in the presence of Cassia alata, Carica papaya, Eremomastax speciosa Eleusine indica, and Polyscias fulva. γδ T cells proliferation was affected to the greatest extent by Polyscias fulva. CONCLUSION: These results clearly show the antioxidant capacity and anti-inflammatory activities of plant extracts collected in Cameroon. These properties of leaves and stem bark extracts may contribute to the value for these plants in traditional medicine and in general medical practice.

Encapsulation of Gibbsite platelets with free radical and controlled radical emulsion polymerization approaches, a small review

NARCIS (Netherlands)

Loiko, O.P.; Spoelstra, A.B.; van Herk, A.M.; Meuldijk, J.; Heuts, J.P.A.

2016-01-01

Water-borne anisotropic polymer-Gibbsite latex particles were prepared by a conventional and an atom transfer radical polymerisation (ATRP) based starved-feed emulsion polymerisation without any chemical modification of the platelet surface. Anionic co-oligomers, synthesised via ATRP, were used in

Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

International Nuclear Information System (INIS)

Wang, Lai-Sheng

2015-01-01

Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent development in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES

Kinetic model for the radical degradation of tri-halonitromethane disinfection byproducts in water

International Nuclear Information System (INIS)

Mezyk, Stephen P.; Mincher, Bruce J.; Cooper, William J.; Kirkham Cole, S.; Fox, Robert V.; Gardinali, Piero R.

2012-01-01

The halonitromethanes (HNMs) are byproducts of the ozonation and chlorine/chloramine treatment of drinking waters. Although typically occurring at low concentrations HNMs have high cytotoxicity and mutagenicity, and may therefore represent a significant human health hazard. In this study, we have investigated the radical based mineralization of fully-halogenated HNMs in water using the congeners bromodichloronitromethane and chlorodibromonitromethane. We have combined absolute reaction rate constants for their reactions with the hydroxyl radical and the hydrated electron as measured by electron pulse radiolysis and analytical measurements of stable product concentrations obtained by 60 Co steady-state radiolysis with a kinetic computer model that includes water radiolysis reactions and halide/nitrogen oxide radical chemistry to fully elucidate the reaction pathways of these HNMs. These results are compared to our previous similar study of the fully chlorinated HNM chloropicrin. The full optimized computer model, suitable for predicting the behavior of this class of compounds in irradiated drinking water, is provided. - Highlights: ► Radical-based mineralization of aqueous halonitromethane disinfection byproducts. ► Constructed kinetic computer model for tri-halogenated halonitromethane removal. ► Model predicted that superoxide reaction is unimportant for halonitromethanes. ► Measured superoxide reaction with chloropicrin was negligibly slow, 4 M −1 s −1 . ► Determined that superoxide reaction with nitrate also insignificant at ∼10 4 M −1 s −1 .

Cumulative abiotic stresses and their effect on the antioxidant defense system in two species of wheat, Triticum durum Desf and Triticum aestivum L.

OpenAIRE

Ibrahim M.M.; Alsahli A.A.; Al-Ghamdi A.A.

2013-01-01

The combined effects of heat and UV-B on the antioxidant system and photosynthetic pigments were investigated in the leaves of T. durum Desf. and Triticum aestivum L. The photosynthetic pigment content, in vitro evaluation of the antioxidant system activities including DPPH radical scavenging activity, and super oxide anion radical scavenging activity were determined. In addition, the antioxidant enzyme activities, such as superoxide dismutase (SOD) and gua...

Mistletonone, a Novel Antioxidative Diarylheptanoid from the Branches and Leaves of Viscum coloratum

Directory of Open Access Journals (Sweden)

Tong-Shui Zhou

2007-03-01

Full Text Available Mistletonone, a novel diarylheptanoid, was isolated from the branches and leaves of Viscum coloratum (Kom. Nakai (Loranthaceae. It was identified as 1,7-di-(p-hydroxyphenyl-5-hydroxyl-cis-2,3-epoxy-1-one on the basis of spectral evidence. The compound showed significant scavenging effects on hydroxyl radicals and superoxide anion radicals in the direct assay using the electron spin resonance (ESR technique.

Free radicals and antioxidants in primary fibromyalgia: an oxidative stress disorder?

Science.gov (United States)

Bagis, Selda; Tamer, Lulufer; Sahin, Gunsah; Bilgin, Ramazan; Guler, Hayal; Ercan, Bahadir; Erdogan, Canan

2005-04-01

The role of free radicals in fibromyalgia is controversial. In this study, 85 female patients with primary fibromyalgia and 80 age-, height-, and weight-matched healthy women were evaluated for oxidant/antioxidant balance. Malondialdehyde is a toxic metabolite of lipid peroxidation used as a marker of free radical damage. Superoxide dismutase is an intracellular antioxidant enzyme and shows antioxidant capacity. Pain was assessed by visual analog scale. Tender points were assessed by palpation. Age, smoking, body mass index (BMI), and duration of disease were also recorded. Malondialdehyde levels were significantly higher and superoxide dismutase levels significantly lower in fibromyalgic patients than controls. Age, BMI, smoking, and duration of disease did not affect these parameters. We found no correlation between pain and number of tender points. In conclusion, oxidant/antioxidant balances were changed in fibromyalgia. Increased free radical levels may be responsible for the development of fibromyalgia. These findings may support the hypothesis of fibromyalgia as an oxidative disorder.

A measurement of the t anti t production cross section in proton-antiproton collisions at {radical}s=1.96 TeV with the DOe detector at the Tevatron using final states with a muon and jets

Energy Technology Data Exchange (ETDEWEB)

Klute, M.

2004-02-01

A preliminary measurement of the t anti t production cross section at {radical}s=1.96 TeV is presented. The {mu}-plus-jets final state is analyzed in a data sample of 94 pb{sup -1} and a total of 14 events are selected with a background expectation of 11.7{+-}1.9 events. The measurement yields: {sigma}{sub p} {sub anti} {sub p{yields}}{sub t} {sub anti} {sub t+X}=2.4{sub -3.5}{sup +4.2}(stat.){sub -2.6}{sup +2.5}(syst.){+-}0.3(lumi.) pb. The analysis, being part of a larger effort to re-observe the top quark in Tevatron Run II data and to measure the production cross section, is combined with results from the available analysis channels. The combined result yields: {sigma}{sub p} {sub anti} {sub p{yields}}{sub t} {sub anti} {sub t+X}=8.1{sub -2.0}{sup +2.2}(stat.){sub -1.4}{sup +1.6}(syst.){+-}0.8(lumi.) pb.

Evaluation of intracellular anion superoxide level, heat shock protein A2 and protamine positive spermatozoa percentages in teratoasthenozoospermia

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Parvin Sabeti

2017-09-01

Full Text Available Background: Teratoasthenozoospermia (TA is a severe form of male infertility with no clear etiology. Objective: To compare the level of intracellular anion superoxide (O2–, heat shock protein A2 (HSPA2 and protamine deficiencies in ejaculated spermatozoa between teratoasthenozoospermic and normozoospermic men. Materials and Methods: In this case- control study, semen samples of 20 infertile men, with TA (with normal morphology lower than 4%_ and total motility lower than 40% as the case group and 20 normozoospermic fertile men as the control group were evaluated for intracellular O2 – and HSPA2 by flow cytometry and protamine deficiency by Chromomycin A3 (CMA3 test. Results: The rate of CMA3+ spermatozoa in the case group was higher than controls (p=0.001. The percentages of HSPA2+ spermatozoa in the cases were significantly lower than controls (p=0.001. Also, intracellular O2 – levels in the case group were significantly higher than controls (p=0.001 and had positive correlations with sperm apoptosis (r=0.79, p=0.01 and CMA3 positive sperm (r=0.76, p=0.01, but negative correlations with normal morphology (r=-0.81, p=0.01 and motility (r=-0.81, p=0.01. There was no significant correlation between intracellular O2 – and HSPA2 in the case group (r=0.041, p=0.79. Conclusion: We suggest that the increase in intracellular O2 –, decrease in spermatozoa HSPA2+, and high percentages of spermatozoa with immature chromatin might be considered as etiologies of infertility in TA patients

Cytometric quantification of singlet oxygen in the human malaria parasite Plasmodium falciparum

NARCIS (Netherlands)

Butzloff, Sabine; Groves, Matthew R; Wrenger, Carsten; Müller, Ingrid B

The malaria parasite Plasmodium falciparum proliferates within human erythrocytes and is thereby exposed to a variety of reactive oxygen species (ROS) such as hydrogen peroxide, hydroxyl radical, superoxide anion, and highly reactive singlet oxygen ((1)O(2)). While most ROS are already well studied

ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

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Blažena Lavová

2014-02-01

Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

Electrolyte Chemistry for Simultaneous Stabilization of Potassium Metal and Superoxide in K-O₂ Batteries.

Science.gov (United States)

Xiao, Neng; Gourdin, Gerald; Wu, Yiying

2018-05-22

In the superoxide batteries based on O2/O2- redox chemistry, identifying an electrolyte to stabilize both alkali metal and superoxide remains challenging due to their reactivity towards electrolyte components. Bis(fluorosulfonyl)imide (FSI-) has been recognized as a "magical anion" for passivating alkali metals. Herein, we illustrate the chemical reactions between FSI- and superoxide, and the resultant dilemma when considering an anode-compatible electrolyte vs. a cathode-compatible one in K-O2 batteries. On one side, the KFSI-dimethoxyethane (DME) electrolyte passivates the potassium metal anode via the cleavage of S-F bond and formation of a KF-rich solid electrolyte interface (SEI). Nevertheless, the KFSI salt is chemically unstable due to the nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable for KO2, but results in mossy deposition and irreversible plating and stripping. In order to circumvent this dilemma, we develop an artificial SEI for K metal anode to achieve long cycle-life K-O2 batteries. This work contributes to the understanding of electrolyte chemistry and guides the development of stable electrolytes and artificial SEI in metal-O2 batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Five Stereoactive Orbitals on Silicon: Charge and Spin Localization in the n-Si4Me10(-•) Radical Anion by Trigonal Bipyramidalization.

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MacLeod, Matthew K; Michl, Josef

2013-05-16

RIUMP2/def2-TZVPPD calculations show that in addition to its usual conformation with charge and spin delocalized over the Si backbone, the isolated Si4Me10(-•) radical anion also has isomeric conformations with localized charge and spin. A structure with localization on a terminal Si atom has been examined in detail. In vacuum, it is calculated to lie 11.5 kcal/mol higher in energy than the charge-and-spin delocalized conformation, and in water the difference is as little as 1.6 kcal/mol. According to natural orbital and localized orbital analyses, the charge-and-spin-carrying terminal Si atom uses five stereoactive hybrid orbitals in a trigonal bipyramidal geometry. Four are built mostly from 3s and 3p atomic orbitals (AOs) and are used to attach a Si3(CH3)7 and three CH3 groups, whereas the larger equatorial fifth orbital is constructed from 4s and 4p AOs and acts as a nonbonding (radical) hybrid orbital with an occupancy of about 0.65 e.

Degradation and intermediates of diclofenac as instructive example for decomposition of recalcitrant pharmaceuticals by hydroxyl radicals generated with pulsed corona plasma in water.

Science.gov (United States)

Banaschik, Robert; Jablonowski, Helena; Bednarski, Patrick J; Kolb, Juergen F

2018-01-15

Seven recalcitrant pharmaceutical residues (diclofenac, 17α-ethinylestradiol, carbamazepine, ibuprofen, trimethoprim, diazepam, diatrizoate) were decomposed by pulsed corona plasma generated directly in water. The detailed degradation pathway was investigated for diclofenac and 21 intermediates could be identified in the degradation cascade. Hydroxyl radicals have been found primarily responsible for decomposition steps. By spin trap enhanced electron paramagnetic resonance spectroscopy (EPR), OH-adducts and superoxide anion radical adducts were detected and could be distinguished applying BMPO as a spin trap. The increase of concentrations of adducts follows qualitatively the increase of hydrogen peroxide concentrations. Hydrogen peroxide is eventually consumed in Fenton-like processes but the concentration is continuously increasing to about 2mM for a plasma treatment of 70min. Degradation of diclofenac is inversely following hydrogen peroxide concentrations. No qualitative differences between byproducts formed during plasma treatment or due to degradation via Fenton-induced processes were observed. Findings on degradation kinetics of diclofenac provide an instructive understanding of decomposition rates for recalcitrant pharmaceuticals with respect to their chemical structure. Accordingly, conclusions can be drawn for further development and a first risk assessment of the method which can also be applied towards other AOPs that rely on the generation of hydroxyl radicals. Copyright © 2017 Elsevier B.V. All rights reserved.

Reaction between peroxynitrite and boronates: EPR spin-trapping, HPLC analyses, and quantum mechanical study of the free radical pathway

Science.gov (United States)

Sikora, Adam; Zielonka, Jacek; Lopez, Marcos; Dybala-Defratyka, Agnieszka; Joseph, Joy; Marcinek, Andrzej; Kalyanaraman, Balaraman

2013-01-01

Recently we showed that peroxynitrite (ONOO−) reacts directly and rapidly with aromatic and aliphatic boronic acids (k ≈ 106 M−1s−1). Product analyses and substrate consumption data indicated that ONOO− reacts stoichiometrically with boronates, yielding the corresponding phenols as the major product (~85–90%), and the remaining products (10–15%) were proposed to originate from free radical intermediates (phenyl and phenoxyl radicals). Here we investigated in detail the minor, free radical pathway of boronate reaction with ONOO−. The electron paramagnetic resonance (EPR) spin-trapping technique was used to characterize the free radical intermediates formed from the reaction between boronates and ONOO−. Using 2-methyl-2-nitrosopropane (MNP) and 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO) spin traps, phenyl radicals were trapped and detected. Although phenoxyl radicals were not detected, the positive effects of molecular oxygen, and inhibitory effects of hydrogen atom donors (acetonitrile, and 2-propanol) and general radical scavengers (GSH, NADH, ascorbic acid and tyrosine) on the formation of phenoxyl radical-derived nitrated product, suggest that phenoxyl radical was formed as the secondary species. We propose that the initial step of the reaction involves the addition of ONOO− to the boron atom in boronates. The anionic intermediate undergoes both heterolytic (major pathway) and homolytic (minor pathway) cleavage of the peroxy (O-O) bond to form phenol and nitrite as a major product (via a non-radical mechanism), or a radical pair PhB(OH)2O•−…•NO2 as a minor product. It is conceivable that phenyl radicals are formed by the fragmentation of PhB(OH)2O•− radical anion. According to the DFT quantum mechanical calculations, the energy barrier for the dissociation of PhB(OH)2O•− radical anion to form phenyl radicals is only a few kcal/mol, suggesting rapid and spontaneous fragmentation of PhB(OH)2O•− radical anion

Evaluation of Antioxidant, Anticholinesterase, and Antidiabetic Potential of Dry Leaves and Stems in Tamarix aphylla Growing Wild in Tunisia.

Science.gov (United States)

Mahfoudhi, Adel; Grosso, Clara; Gonçalves, Rui F; Khelifi, Eltaief; Hammami, Saoussen; Achour, Sami; Trabelsi-Ayadi, Malika; Valentão, Patrícia; Andrade, Paula B; Mighri, Zine

2016-12-01

Tamarix aphylla (L.) Karst. has a wide geographic distribution and was employed in traditional medicine as astringent, anti-rheumatic and to treat fever. T. aphylla leaves and stems extracts were studied from both chemical and biological points of view to assess the antidiabetic, anticholinesterase and antioxidant potential of this species. The HPLC/Diode Array Detector (DAD) analysis showed the presence of 14 phenolic compounds (gallic, caffeic, p-coumaric, ferulic and ellagic acids, kaempferol, quercetin, quercetin 3-O-galactoside and six flavonol derivatives). This is the first study reporting a comparative study of the biological activities of different extracts from T. aphylla. High activities were obtained against DPPH radical, superoxide anion radical (O2∙-) and nitric oxide radical ( • NO) in a concentration-dependent manner, the most active extracts being the polar ones. T. aphylla also showed moderate protective effects against acetylcholinesterase, but no effects were observed against butyrylcholinesterase. Against α-glucosidase the MeOH extracts displayed IC 50 values from 8.41 to 24.81 μg/ml. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

Antipyretic, analgesic, anti-inflammatory and antioxidant activities of two major chromenes from Melicope lunu-ankenda.

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Johnson, Anil J; Kumar R, Arun; Rasheed, Sherin A; Chandrika, Sreeja P; Chandrasekhar, Arun; Baby, Sabulal; Subramoniam, Appian

2010-07-20

Melicope lunu-ankenda (Gaertn.) T.G. Hartley is used in Indian traditional medicine for fever, improving complexion and as a tonic. Previous studies have isolated fungicidal, antifeedant, anti-inflammatory and immunomodulatory compounds from Melicope lunu-ankenda. This study is aimed at the isolation and biological activity screening of potential molecules from the volatile oils and extracts of Melicope lunu-ankenda in the light of traditional applications. Volatile oil of Melicope lunu-ankenda leaves was isolated by hydrodistillation, characterized by GC-FID, GC-MS, LRI determination, Co-GC and database searches. Major chromene-type compounds in Melicope lunu-ankenda leaf oil, evodione and leptonol, were isolated by preparative TLC and characterized by UV-Vis, IR, 1H-, 13C-, 13C-DEPT NMR and EIMS. They were also isolated from the petroleum ether and acetone extracts of the leaves of Melicope lunu-ankenda by column chromatography in petroleum ether-ethyl acetate. Their contents in leaf oil, leaf and inflorescence extracts were estimated by HPTLC. Antipyretic (Baker's yeast-induced fever test), analgesic (acetic acid-induced writhing, tail immersion assays), anti-inflammatory (carrageenan-induced paw edema) and in vitro antioxidant (DPPH radical, superoxide radical scavenging) activities of evodione and leptonol were tested. Gas chromatographic analyses found 50.7% monoterpene hydrocarbons, 0.4% oxygenated monoterpenes, 3.2% sesquiterpene hydrocarbons, 0.7% oxygenated sesquiterpenes and 43.7% chromene-type compounds in Melicope lunu-ankenda leaf oil, with evodione (20.2%) and leptonol (22.5%) as its two major constituents. HPTLC estimations in the petroleum ether, acetone extracts (leaf, inflorescence) and leaf oil found evodione 1.0% (dr. wt., leaf), 1.1% (inflorescence), 0.04% (fr. wt. leaves, leaf oil), and leptonol 0.3% (leaf), 0.3% (inflorescence) and 0.04% (leaf oil). Leptonol (200 mg/kg) showed good antipyretic activity. DPPH radical scavenging assay found

Genotoxic potency of mercuric chloride in gill cells of marine gastropod Planaxis sulcatus using comet assay

Digital Repository Service at National Institute of Oceanography (India)

Bhagat, J.; Ingole, B.S.

in Thane Creek area Mumbai. Chemosphere 69 (6):972-978 Mitchelmore CL, Birmelin C, Chipman JK, Livingstone DR (1998) Evidence for cytochrome P-450 catalysis and free radical involvement in the production of DNA strand breaks by benzo[ a... mechanisms through which mercury can cause DNA damage. One of them are production of reactive oxygen species such as superoxide anion radical (O2 –), hydrogen peroxide (H2O2), and hydroxyl radicals (OH●) (Tsuzuki et al., 1994). The antioxidant mechanism...

Oxidative Mechanisms of Monocyte-Mediated Cytotoxicity

Science.gov (United States)

Weiss, Stephen J.; Lobuglio, Albert F.; Kessler, Howard B.

1980-01-01

Human monocytes stimulated with phorbol myristate acetate were able to rapidly destroy autologous erythrocyte targets. Monocyte-mediated cytotoxicity was related to phorbol myristate acetate concentration and monocyte number. Purified preparations of lymphocytes were incapable of mediating erythrocyte lysis in this system. The ability of phorbol myristate acetate-stimulated monocytes to lyse erythrocyte targets was markedly impaired by catalase or superoxide dismutase but not by heat-inactivated enzymes or albumin. Despite a simultaneous requirement for superoxide anion and hydrogen peroxide in the cytotoxic event, a variety of hydroxyl radical and singlet oxygen scavengers did not effect cytolysis. However, tryptophan significantly inhibited cytotoxicity. The myeloperoxidase inhibitor cyanide enhanced erythrocyte destruction, whereas azide reduced it modestly. The inability of cyanide to reduce cytotoxicity coupled with the protective effect of superoxide dismutase suggests that cytotoxicity is independent of the classic myeloperoxidase system. We conclude that monocytes, stimulated with phorbol myristate acetate, generate superoxide anion and hydrogen peroxide, which together play an integral role in this cytotoxic mechanism.

Neuronal uptake and intracellular superoxide scavenging of a fullerene (C60)-poly(2-oxazoline)s nanoformulation

KAUST Repository

Tong, Jing

2011-05-01

Fullerene, the third allotrope of carbon, has been referred to as a "radical sponge" because of its powerful radical scavenging activities. However, the hydrophobicity and toxicity associated with fullerene limits its application as a therapeutic antioxidant. In the present study, we sought to overcome these limitations by generating water-soluble nanoformulations of fullerene (C(60)). Fullerene (C(60)) was formulated with poly(N-vinyl pyrrolidine) (PVP) or poly(2-alkyl-2-oxazoline)s (POx) homopolymer and random copolymer to form nano-complexes. These C(60)-polymer complexes were characterized by UV-vis spectroscopy, infrared spectroscopy (IR), dynamic light scattering (DLS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Cellular uptake and intracellular distribution of the selected formulations in catecholaminergic (CATH.a) neurons were examined by UV-vis spectroscopy, immunofluorescence and immunogold labeling. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the ability of these C(60)-polymer complexes to scavenge superoxide. Their cytotoxicity was evaluated in three different cell lines. C(60)-POx and C(60)-PVP complexes exhibited similar physicochemical properties and antioxidant activities. C(60)-poly(2-ethyl-2-oxazoline) (PEtOx) complex, but not C(60)-PVP complex, were efficiently taken up by CATH.a neurons and attenuated the increase in intra-neuronal superoxide induced by angiotensin II (Ang II) stimulation. These results show that C(60)-POx complexes are non-toxic, neuronal cell permeable, superoxide scavenging antioxidants that might be promising candidates for the treatment of brain-related diseases associated with increased levels of superoxide.

Effects of the peroxisome proliferator clofibric acid on superoxide dismutase expression in the human HepG2 hepatoma cell line.

Science.gov (United States)

Bécuwe, P; Bianchi, A; Keller, J M; Dauça, M

1999-09-15

We examined the effects of clofibric acid, a peroxisome proliferator, on the production of superoxide radicals, on the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), and on the expression of superoxide dismutases (SODs) in the human HepG2 hepatoma cell line. To this end, HepG2 cells were treated for 1 or 5 days with 0.25, 0.50, or 0.75 mM clofibric acid. The production of superoxide radicals was only enhanced in HepG2 cells exposed for 5 days to the different clofibric acid concentrations. However, this overproduction of superoxide radicals was not accompanied by increased rates of lipid peroxidation, as the MDA and 4-HNE levels did not change significantly. Manganese (Mn) SOD activity was increased when HepG2 cells were treated for 1 day with 0.50 or 0.75 mM clofibric acid. For this duration of treatment, no change was observed in total SOD and copper/zinc (Cu/Zn) SOD activities. For a 5-day treatment, total SOD and MnSOD activities as well as the enzyme apoprotein and MnSOD mRNA levels increased whatever the clofibric acid concentration used. This transcriptional induction of the MnSOD gene was correlated with an activation of the activator protein-1 transcription factor for 1 and 5 days of treatment, but was independent of nuclear factor-kappa B and of peroxisome proliferator-activated receptor. On the other hand, the PP exerted very little effect if any on Cu,ZnSOD expression. In contrast to rodent data, PP treatment of human hepatoma cells induces MnSOD expression.

Reductive Umpolung of Carbonyl Derivatives with Visible-Light Photoredox Catalysis: Direct Access to Vicinal Diamines and Amino Alcohols via α-Amino Radicals and Ketyl Radicals

KAUST Repository

Fava, Eleonora; Millet, Anthony; Nakajima, Masaki; Loescher, Sebastian; Rueping, Magnus

2016-01-01

Visible-light-mediated photoredox-catalyzed aldimine-aniline and aldehyde-aniline couplings have been realized. The reductive single electron transfer (SET) umpolung of various carbonyl derivatives enabled the generation of intermediary ketyl and α-amino radical anions, which were utilized for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols. Anilines can be coupled with aldimines or aldehydes in a visible-light-mediated photoredox-catalyzed process. Reductive single electron transfer (SET) umpolung of the carbonyl derivatives leads to the generation of intermediary ketyl and α-amino radical anions, which were used for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols.

Reductive Umpolung of Carbonyl Derivatives with Visible-Light Photoredox Catalysis: Direct Access to Vicinal Diamines and Amino Alcohols via α-Amino Radicals and Ketyl Radicals

KAUST Repository

Fava, Eleonora

2016-05-02

Visible-light-mediated photoredox-catalyzed aldimine-aniline and aldehyde-aniline couplings have been realized. The reductive single electron transfer (SET) umpolung of various carbonyl derivatives enabled the generation of intermediary ketyl and α-amino radical anions, which were utilized for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols. Anilines can be coupled with aldimines or aldehydes in a visible-light-mediated photoredox-catalyzed process. Reductive single electron transfer (SET) umpolung of the carbonyl derivatives leads to the generation of intermediary ketyl and α-amino radical anions, which were used for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols.

Chromatographic analysis, anti-proliferative and radical scavenging activity of Pinus wallichina essential oil growing in high altitude areas of Kashmir, India.

Science.gov (United States)

Yousuf Dar, Mohd; Shah, Wajaht A; Mubashir, Sofi; Rather, Manzoor A

2012-10-15

To evaluate the in vitro anti-proliferative and radical scavenging properties of the essential oil and its fractions and to determine the chemo-type of P. wallichiana essential oil. Pinus wallichiana oil was extracted by hydro-distillation and fractionated by silica gel column chromatography method. The oil and its fractions were analyzed by Gas chromatography, Gas chromatography-mass spectrometry and (13)C NMR. Different concentrations of oil 12.5, 25, 50 and 100μg/ml and single concentration 50μg/ml of its fractions B(1), B(2), A(2), G(2), Uk(13) and I(2) were evaluated for its anti-proliferative activity by in vitro {3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide} assay against human monocyte, lung carcinoma, liver adenocarcinoma, prostate and ovarian carcinoma, while as the radical scavenging activity was evaluated by different in vitro DPPH assays. The analyses indicated the presence of 17 constituents with β-pinene (46.8%) and α-pinene (25.2%) as major constituents. The oil and its fractions showed significant anti-proliferative activity. The radical scavenging activity also showed good results. The oil could be used as a drug to control the diseases like cancer, cirrhosis and arteriosclerosis, caused by reactive oxygen species. Copyright © 2012 Elsevier GmbH. All rights reserved.

Evaluation of Polyphenol Anthocyanin-Enriched Extracts of Blackberry, Black Raspberry, Blueberry, Cranberry, Red Raspberry, and Strawberry for Free Radical Scavenging, Reactive Carbonyl Species Trapping, Anti-Glycation, Anti-β-Amyloid Aggregation, and Microglial Neuroprotective Effects

Directory of Open Access Journals (Sweden)

Hang Ma

2018-02-01

Full Text Available Glycation is associated with several neurodegenerative disorders, including Alzheimer’s disease (AD, where it potentiates the aggregation and toxicity of proteins such as β-amyloid (Aβ. Published studies support the anti-glycation and neuroprotective effects of several polyphenol-rich fruits, including berries, which are rich in anthocyanins. Herein, blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts were evaluated for: (1 total phenolic and anthocyanins contents, (2 free radical (DPPH scavenging and reactive carbonyl species (methylglyoxal; MGO trapping, (3 anti-glycation (using BSA-fructose and BSA-MGO models, (4 anti-Aβ aggregation (using thermal- and MGO-induced fibrillation models, and, (5 murine microglia (BV-2 neuroprotective properties. Berry crude extracts (CE were fractionated to yield anthocyanins-free (ACF and anthocyanins-enriched (ACE extracts. The berry ACEs (at 100 μg/mL showed superior free radical scavenging, reactive carbonyl species trapping, and anti-glycation effects compared to their respective ACFs. The berry ACEs (at 100 μg/mL inhibited both thermal- and MGO-induced Aβ fibrillation. In addition, the berry ACEs (at 20 μg/mL reduced H2O2-induced reactive oxygen species production, and lipopolysaccharide-induced nitric oxide species in BV-2 microglia as well as decreased H2O2-induced cytotoxicity and caspase-3/7 activity in BV-2 microglia. The free radical scavenging, reactive carbonyl trapping, anti-glycation, anti-Aβ fibrillation, and microglial neuroprotective effects of these berry extracts warrant further in vivo studies to evaluate their potential neuroprotective effects against AD.

Isolation and identification of a new homoisoflavan with potent antioxidant activity from Commelina Elegans

International Nuclear Information System (INIS)

Kabbash, A.; Yagi, A.; Ishizu, T.; Haraguchi, H.; Fujioka, T.; Moustafa, S.M.; El-Bassouny, Ashraf A.

2008-01-01

Potent antioxidative compounds have been isolated from the ethyl acetate extract of Commelina Elegans, Commelinaceae, using a repeated column chromatography. On the basis of spectral analysis, the compounds were identified as brazilin, brazilein and the new homoisoflavan-3, 7, 9, 3, 4-ol (4-4) dimer with X- and Y-conformers. The compounds inhibited both enzymatic lipid peroxidation using a rat liver microsomes and mitochondria and non-enzymatic reactions. The compounds completely protected the activities of the mitochondrial enzymes NADH- and succinate-cytochrome c reductase. Furthermore, radical scavenging activity on enzymatically and non-enzymatically generated superoxide anion was investigated. Electron spin resonance using spin trapping method suggested that the compounds have potent superoxide anion scavenging activities. (author)

Effects of topical vitamin E on corneal superoxide dismutase, glutathione peroxidase activities and polymorphonuclear leucocyte infiltration after photorefractive keratectomy.

Science.gov (United States)

Bilgihan, Ayse; Bilgihan, Kamil; Yis, Ozgür; Sezer, Cem; Akyol, Gülen; Hasanreisoglu, Berati

2003-04-01

Photorefractive keratectomy (PRK) induces free radical formation and polymorphonuclear (PMN) cell infiltration in the cornea. Vitamin E is a free radical scavenger and protects the cells from reactive oxygen species. We investigated the effects of topical vitamin E on corneal PMN cell infiltration and corneal antioxidant enzyme activities after PRK. We studied four groups, each consisting of seven eyes. Group 1 were control eyes. In group 2 the corneal epithelium was removed by a blunt spatula (epithelial scrape). In group 3, corneal photoablation (59 micro m, 5 dioptres) was performed after epithelial removal (traditional PRK). In group 4 we tested the effects of topical Vitamin E after traditional PRK. Corneal tissues were removed and studied with enzymatic analysis (measurement of corneal superoxide dismutase and glutathione peroxidase activities) and histologically. Stromal PMN leucocyte counts were significantly higher after mechanical epithelial removal and traditional PRK (p < 0.05). Corneal superoxide dismutase and glutathione peroxidase activities decreased significantly after mechanical epithelial removal and traditional PRK (p < 0.05). In group 4, treated with vitamin E, corneal superoxide dismutase activity did not differ significantly from that in the medically non-treated groups, nor did corneal PMN cell infiltration after traditional PRK. The reduction of corneal glutathione peroxidase activity after PRK was reduced significantly after topical vitamin E treatment. Topical vitamin E treatment may be useful for reducing the harmful effects of reactive oxygen radical after epithelial scraping and PRK in that it increases corneal glutathione peroxidase activity.

Flavonoids in the development of functional meat products: A review

Directory of Open Access Journals (Sweden)

Pramod K. Singh

2013-06-01

Full Text Available Flavonoids or bioflavonoids are unique low molecular weight ubiquitous polyphenolic compounds produced by plants during their metabolic activities as a secondary metabolites and responsible for major organoleptic characteristics and health benefits of plant derived foods. The flavonoids are potent antioxidants agents and protect the cells by scavenging and inhibiting the production and initiation of free radicals, superoxide anions and lipid peroxy radicals. Besides potent antioxidant capacity, flavonoids also shows antimicrobial, antimutagenic, antidiabetic, antithrombosis, antirheumatic, antiatherosclerotic, antiallergic, anti-inflammatory, antiulcers and hepatoprotectives and better termed as neutraceuticals. The antioxidant capacity of meat is very low and this can be increased by adding flavonoids in meat during processing in the form of plant parts rich in flavonoids such as seeds, fruit skin or peel, bark and flower as raw or in extract form without comprising the sensory attributes of meat and meat products. [Vet World 2013; 6(8.000: 573-578

[A preliminary study of anti-aging and wound healing of recombination cytoglobin].

Science.gov (United States)

Li, Zhao-Fa; Zhao, Xiao-Fang; Zhang, Ting-Ting

2012-01-01

In this paper, the preliminary study on antioxidant, enhancement of antioxidant enzymes activity, reducing the content of oxygen free radicals, delaying skin aging of the recombination cytoglobin (rCygb) purified by our lab were investigated through human keratinocyte cell line (HaCAT) H2O2 oxidative stress model, mouse skin aging model caused by continuous subcutaneous injection D-gal, rat acute liver injury model induced by CCl4 and rat skin wound healing model. The results showed that rCygb improved the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), reduced the activities of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) as well as decreased the content of malondialdehyde (MDA). Skin biopsy showed that rCygb promoted angiogenesis, increased expression of collagen and improved the anti-inflammatory ability. All results displayed that rCygb improved the oxygen free radical scavenging ability, delayed skin aging and promoted wound healing.

Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag"+/TiO_2: Influence of electron donating and withdrawing substituents

International Nuclear Information System (INIS)

Xiao, Jiadong; Xie, Yongbing; Han, Qingzhen; Cao, Hongbin; Wang, Yujiao; Nawaz, Faheem; Duan, Feng

2016-01-01

Highlights: • A weak EWG benefited photocatalytic oxidation of phenols the most. • Phenolic compounds were dominantly oxidized by ·O_2"−, rather than ·OH, "1O_2 or h"+. • ·O_2"− preferred to nucleophilically attack EDG substituted phenols. • ·O_2"− more likely electrophilically attacked EWG substituted phenols. • ·O_2"− simultaneously nucleophilically and electrophilically assaulted p-chlorophenol. - Abstract: A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag"+/TiO_2 suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (·O_2"−) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between ·O_2"− and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of ·O_2"− and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by ·O_2"−, while ·O_2"− preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by ·O_2"− could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate constant. Possible reactive positions on the phenolic compounds were also detailedly uncovered.

Polar-Nonpolar Radical Copolymerization under Li+ Catalysis

Science.gov (United States)

2008-09-21

bonds or aromatic rings. Thus, we propose that a transfer of a methyl radical from CB11Me12C to IB triggers a radical polymerization chain that yields ...b-PIB and the resulting CB11Me11 byproduct concurrently triggers a cationic polymerization chain that yields l-PIB terminated with a carborate anion...tetrahydrofuran and passed through a column of alumina about five times to remove the bulk of the catalyst. A Soxhlet apparatus was used to recover

Use of spin traps to detect superoxide production in living cells by electron paramagnetic resonance (EPR) spectroscopy.

Science.gov (United States)

Abbas, Kahina; Babić, Nikola; Peyrot, Fabienne

2016-10-15

Detection of superoxide produced by living cells has been an on-going challenge in biology for over forty years. Various methods have been proposed to address this issue, among which spin trapping with cyclic nitrones coupled to EPR spectroscopy, the gold standard for detection of radicals. This technique is based on the nucleophilic addition of superoxide to a diamagnetic cyclic nitrone, referred to as the spin trap, and the formation of a spin adduct, i.e. a persistent radical with a characteristic EPR spectrum. The first application of spin trapping to living cells dates back 1979. Since then, considerable improvements of the method have been achieved both in the structures of the spin traps, the EPR methodology, and the design of the experiments including appropriate controls. Here, we will concentrate on technical aspects of the spin trapping/EPR technique, delineating recent breakthroughs, inherent limitations, and potential artifacts. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparing Positively and Negatively Charged Distonic Radical Ions in Phenylperoxyl Forming Reactions.

Science.gov (United States)

Williams, Peggy E; Marshall, David L; Poad, Berwyck L J; Narreddula, Venkateswara R; Kirk, Benjamin B; Trevitt, Adam J; Blanksby, Stephen J

2018-06-04

In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature combustion and atmospheric processing of volatile organic compounds. We have previously demonstrated the application of charge-tagged phenyl radicals to explore the outcomes of these reactions using ion trap mass spectrometry. Here, we present a side-by-side comparison of rates and product distributions from the reaction of positively and negatively charge tagged phenyl radicals with dioxygen. The negatively charged distonic radical ions are found to react with significantly greater efficiency than their positively charged analogues. The product distributions of the anion reactions favor products of phenylperoxyl radical decomposition (e.g., phenoxyl radicals and cyclopentadienone), while the comparable fixed-charge cations yield the stabilized phenylperoxyl radical. Electronic structure calculations rationalize these differences as arising from the influence of the charged moiety on the energetics of rate-determining transition states and reaction intermediates within the phenylperoxyl reaction manifold and predict that this influence could extend to intra-molecular charge-radical separations of up to 14.5 Å. Experimental observations of reactions of the novel 4-(1-carboxylatoadamantyl)phenyl radical anion confirm that the influence of the charge on both rate and product distribution can be modulated by increasing the rigidly imposed separation between charge and radical sites. These findings provide a generalizable framework for predicting the influence of charged groups on polarizable radicals in gas phase distonic radical ions. Graphical Abstract.

Cytotoxic and radioprotective effects of Podophyllum hexandrum.

Science.gov (United States)

Shukla, Sandeep Kumar; Chaudhary, Pankaj; Prem Kumar, Indracanti; Afrin, Farhat; Puri, Satish Chandra; Qazi, Ghulam Nabi; Sharma, Rakesh Kumar

2006-07-01

Podophyllum hexandrum, a herb thriving in Himalayas has already been reported to exhibit antitumor and radioprotective properties. Present study was undertaken to unravel the possible mechanism responsible for the cytotoxic and radioprotective properties of REC-2001, a fraction isolated from the rhizome of P. hexandrum using murine peritoneal macrophages and plasmid DNA as model systems. Cell death, levels of intracellular reactive oxygen species (ROS) and apoptosis were studied employing trypan blue exclusion assay, dichlorofluorescein diacetate and DNA fragmentation assay, respectively. Superoxide anions, hydroxyl radicals and DNA damage were estimated following nitroblue tetrazolium, 2-deoxyribose degradation and plasmid DNA relaxation assays, respectively. Pre-irradiation administration of REC-2001 to peritoneal macrophages in the concentration range of 25-200μg/ml significantly reduced radiation induced ROS generation, DNA damage, apoptosis and cell killing in comparison to radiation control group indicating radioprotective potential. Studies with plasmid DNA indicated the ability of REC-2001 to inhibit 20Gy induced single and double strand breaks further supporting the antioxidative potential. However, REC-2001 in a dose-dependent fashion induced cell death, ROS and DNA fragmentation indicating the cytotoxic nature. REC-2001, in presence of 100μM copper sulfate, generated significant amount of hydroxyl radicals and superoxide anions indicating ability to act as a pro-oxidant in presence of metal ions. The superoxide anion generation was found to be sensitive to metal chelators like EDTA and deferoxamine mesylate (DFR). These results suggest that the ability of REC-2001 to act as a pro-oxidant in presence of metal ions and antioxidant in presence of free radicals might be responsible for cytotoxic and radioprotective properties.

Oxidation of caffeine by phosphate radical anion in aqueous ...

Indian Academy of Sciences (India)

Unknown

reactions in our body generate reactive oxygen species mainly comprising free radicals .... caffeine might be acting as a sensitizer to transfer energy to PDP to produce phosphate ... The lifetime of the excited singlet 21 state of caffeine is of the.

In Vitro Antioxidant Evaluation of Some Mannich Bases which Contain Bis-1,2,4 -Triazole Derivative

International Nuclear Information System (INIS)

Parlak, A. E.; Karatepe, M.; Koparir, M.; Alayunt, N. O.; Keser, S.; Dastan, S. D.; Ulas, M.; Celik, S.

2015-01-01

This study aims to examine the antioxidant effects of some Mannich bases containing bis-1, 2, 4 triazole, which are synthesized afresh. The antioxidant activities of the derivatives were measured using different methods in this study, including reducing power capacity, metal chelating activity, superoxide anion radicals scavenging activity, H/sub 2/ O/sub 2/ scavenging activity and hydroxyl radical scavenging. As a result, derivatives had efficient antioxidant and free radical scavenging activity when compared to ascorbic acid, BHT and alpha-tocopherol as associated antioxidants. (author)

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.

High-sensitivity imaging method of singlet oxygen and superoxide anion in photodynamic and sonodynamic actions

Science.gov (United States)

Xing, Da; He, Yonghong; Hao, Min; Chen, Qun

2004-07-01

A novel method of photodynamic diagnosis (PDD) of cancer mediated by chemiluminescence (CL) probe is presented. The mechanism for photodynamic therapy (PDT) involves reactive oxygen species (ROS), such as singlet oxygen (1O2) and superoxide (O2-), generated by during the photochemical process. Both 1O2 and O2- can react with Cypridina luciferin analogue (FCLA), a highly selective CL probe for detecting the ROS. Chemiluminescence from the reaction of FCLA with the ROS, at about 530 nm, was detected by a highly sensitive ICCD system. The CL was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) in a sample solution. Similar phenomena, with lesser extents of changes, were observed at the additions of 10 μmol/L superoxide dismutase (SOD), 10 mmol/L mannitol, and 100 μg/mL catalase, respectively. This indicates that the detected CL signals were mainly from ROS generated during the photosensitization reactions. Also, the chemiluminescence method was used to detect the ROS during sonodynamic action, both in vitro and in vivo. ROS formation during sonosensitizations of HpD and ATX-70 were detected using our newly-developed imaging technique, in real time, on tumor bearing animals. This method can provide a new means in clinics for tumor diagnosis.

Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

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Béla Fiser

Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

Nitrogen, oxygen or sulfur containing heterocyclic compounds as analgesic drugs used as modulators of the nitroxidative stress.

Science.gov (United States)

Salat, Kinga; Moniczewski, Andrzej; Librowski, Tadeusz

2013-03-01

Numerous lines of evidence suggest that heterocyclic compounds used as analgesic, anti-inflammatory and anti-migraine agents can be potent regulators of the nitroxidative stress and targeting free nitrogen and oxygen radicals is a very promising strategy for future pain management. Both classical analgesics (nonsteroidal anti-inflammatory drugs, opioid drugs) and many analgesic adjuvants, including desipramine, duloxetine, fluoxetine, paroxetine, escitalopram, phenytoin or carbamazepine and α-lipoic acid can modulate the balance between pro-oxidant and antioxidant processes in the mammalian tissues and these properties of drugs such as indomethacin, meloxicam, tenoxicam, valdecoxib or some metabolites of analgesic drugs formed by the activity of tissue peroxidases may contribute to their clinical efficacy and drug-related toxic effects, including gastrointestinal ulcers, hepatic failure, agranulocytosis, aplastic anemia, neutropenia, opiate-induced hyperalgesia and tolerance. The antioxidant capacities of novel heterocyclic compounds, including the compounds acting either by prevention of formation or catalyzed decomposition of peroxynitrite anion (ONOO-), namely the peroxynitrite decomposition catalysts or as superoxide (O2 •-)-scavengers which are the functional mimetics of superoxide dismutase (SOD) enzymes (SODm), as well as the derivatives of 6-nitro-3,4-methylenedioxyphenyl-Nacylhydrazone (LASSBio-881) or γ-butyrolactone (LPP1, BM113, BM113A, BM138 and BM138A) are also discussed as potent and promising future heterocyclic analgesics.

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

Antioxidant Capacity and Proanthocyanidin Composition of the Bark of Metasequoia glyptostroboides.

Science.gov (United States)

Chen, Fengyang; Zhang, Lin; Zong, Shuling; Xu, Shifang; Li, Xiaoyu; Ye, Yiping

2014-01-01

Metasequoia glyptostroboides Hu et Cheng is the only living species in the genus Metasequoia Miki ex Hu et Cheng (Taxodiaceae), which is well known as a "living fossil" species. In the Chinese folk medicine, the leaves and bark of M. glyptostroboides are used as antimicrobic, analgesic, and anti-inflammatory drug for dermatic diseases. This study is the first to report the free radical scavenging capacity, antioxidant activity, and proanthocyanidin composition of the bark of M. glyptostroboides. We observed total of six extracts and fractions, which were easily obtained by water-ethanol extraction and followed by a further separation with D101 resin column chromatography, had significant DPPH radical, superoxide anion radical, and hydroxyl radical scavenging capacity, total antioxidative capacity (T-AOC), lipid peroxidation inhibitory activity, and metal ions chelating capacity. The fraction MGEB, which was obtained by 60% ethanol extraction and followed by a further separation with D101 resin column chromatograph, possessed the highest proanthocyanidin content and the highest free radical scavenging and antioxidant activities. Furthermore, MGEB could significantly protect against CCl4 induced acute liver injury through inhibition of oxidative stress in mice. In addition, ten proanthocyanidins were isolated from MGEB, and six of them were firstly reported from this plant.

Antioxidant Capacity and Proanthocyanidin Composition of the Bark of Metasequoia glyptostroboides

Directory of Open Access Journals (Sweden)

Fengyang Chen

2014-01-01

Full Text Available Metasequoia glyptostroboides Hu et Cheng is the only living species in the genus Metasequoia Miki ex Hu et Cheng (Taxodiaceae, which is well known as a “living fossil” species. In the Chinese folk medicine, the leaves and bark of M. glyptostroboides are used as antimicrobic, analgesic, and anti-inflammatory drug for dermatic diseases. This study is the first to report the free radical scavenging capacity, antioxidant activity, and proanthocyanidin composition of the bark of M. glyptostroboides. We observed total of six extracts and fractions, which were easily obtained by water-ethanol extraction and followed by a further separation with D101 resin column chromatography, had significant DPPH radical, superoxide anion radical, and hydroxyl radical scavenging capacity, total antioxidative capacity (T-AOC, lipid peroxidation inhibitory activity, and metal ions chelating capacity. The fraction MGEB, which was obtained by 60% ethanol extraction and followed by a further separation with D101 resin column chromatograph, possessed the highest proanthocyanidin content and the highest free radical scavenging and antioxidant activities. Furthermore, MGEB could significantly protect against CCl4 induced acute liver injury through inhibition of oxidative stress in mice. In addition, ten proanthocyanidins were isolated from MGEB, and six of them were firstly reported from this plant.

Role of free radicals in radiation chemical aging

Energy Technology Data Exchange (ETDEWEB)

Greenstock, C L

1986-01-01

Ionizing radiation initiates chemical changes in DNA, phospholipid membranes and other critical cell targets, that, if allowed to accumulate unrepaired, may lead to aging and other chronic effects. The chemical effects are free radical mediated, the principal damaging species being radical OH and to a lesser extent O2-anion radical and the molecular product H/sub 2/O/sub 2/. Many compounds can act in combination with ionizing radiation, to amplify the potential oxidative stress. Chemicals, ultra-violet light, lipid peroxides and their breakdown products may increase the extent of acute and chronic radiobiological effects.

Tobacco Smoke: Involvement of Reactive Oxygen Species and Stable Free Radicals in Mechanisms of Oxidative Damage, Carcinogenesis and Synergistic Effects with Other Respirable Particles

Science.gov (United States)

Valavanidis, Athanasios; Vlachogianni, Thomais; Fiotakis, Konstantinos

2009-01-01

Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS) in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR) and spin-trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2•−) and hydroxyl (HO•) radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT) solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2’-deoxyguanosine (a biomarker for carcinogenesis). Also, we observed synergistic effects in the generation of HO•, through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc.) and ambient particulate matter (PM), such as PM10, PM2.5 and diesel exhaust particles (DEP). The highest synergistic effects was observed with the asbestos fibres (freshly grounded), PM2.5 and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and “bio-filters” with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase. PMID:19440393

Tobacco Smoke: Involvement of Reactive Oxygen Species and Stable Free Radicals in Mechanisms of Oxidative Damage, Carcinogenesis and Synergistic Effects with Other Respirable Particles

Directory of Open Access Journals (Sweden)

Konstantinos Fiotakis

2009-02-01

Full Text Available Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR and spin- trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2·- and hydroxyl (HO· radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2’-deoxyguanosine (a biomarker for carcinogenesis.Also, we observed synergistic effects in the generation of HO·, through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc. and ambient particulate matter (PM, such as PM10, PM2.5 and diesel exhaust particles (DEP. The highest synergistic effects was observed with the asbestos fibres (freshly grounded, PM2.5 and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and “bio-filters” with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase.

Oxygen-dependent radiosensitivity of Escherichia coli and mitigation in lethality by superoxide dismutase

International Nuclear Information System (INIS)

Niwa, Taeko; Yamaguchi, Hikoyuki; Yano, Keiji

1978-01-01

Oxygen-dependent radiosensitivity of Escherichia coli W3623 his - was confirmed. Regarding cellular superoxide dismutase (SOD), cells grown oxically gained higher activity than those anoxically, however, the reinforced enzyme level could not compensate the oxygen effect, i.e., the enhanced lethal effect of oxic γ-irradiation. Rather, the enhancement of oxygen effect was found in cells grown oxically compared with those anoxically. Oxygen enhanced lethality was mitigated to the extent by the amount of added SOD into the cell suspension to be irradiated. The results supported a proposal that superoxide anion, O 2 - , is involved in the oxygen effect, with the most likely site of the damage in the outer structure of cell but not in the cell matrix. Reverse oxygen effect could be found with lambda phage DNA in transfecting ability. Added SOD protected phage DNA somewhat in oxic irradiation. While considerable protections were found in anoxic one with the added SOD even autoclaved but their function was still unknown. (auth.)

Modifiers of free radicals inhibit in vitro the oncogenic actions of x-rays, bleomycin, and the tumor promoter 12-O-tetradecanoylphorbol 13-acetate

International Nuclear Information System (INIS)

Borek, C.; Troll, W.

1983-01-01

Using short-term cultures of hamster embryo cells, we have examined the effects of the free-radical scavenger superoxide dismutase (superoxide:superoxide oxidoreductase, EC 1.15.1.1) and the enzyme catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) on x-ray-and bleomycin-induced transformation and on the enhancement of radiogenic transformation by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA). We find that superoxide dismutase inhibits (i) transformation induced by x-ray and bleomycin and (ii) promotional action of TPA in vitro. The results suggest that the oncogenic action of x-rays and bleomycin and the enhancement of oncogenic transformation by TPA are mediated in part by free radicals. The findings also suggest that superoxide dismutase can serve as an inhibitor of oncogenesis and that its actions, as seen in this in vitro system, are most predominantly on inhibiting late events in the progression of cellular transformation--those associated with promotion

The influence of graded levels of available phosphorus on growth performance, muscle antioxidant and flesh quality of young grass carp (Ctenopharyngodon idella

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Jing Wen

2015-06-01

Full Text Available Growth, muscle composition, meat quality characteristics and antioxidant capacity in muscle of young grass carp (Ctenopharyngodon idella (initial weight 282.9 ± 3.3 g fed graded levels of phosphorus (1.0, 2.5, 3.8, 5.6, 7.8 and 9.5 g/kg diet for 8 wk were investigated. Results indicated that percentage weight gain, feed intake, feed efficiency, serum phosphorus and alkaline phosphatase were improved with optimal phosphorus supplementations (P < 0.05. Muscle protein content and water holding capacity were significantly elevated, while moisture, lipid and ash contents were significantly decreased with dietary phosphorus to a certain level (P < 0.05. The meat shear force value and hydroxyproline content were not influenced by different levels of phosphorus. Muscle anti-hydroxyl radical, superoxide dismutase, catalase, glutathione S-transferase activities and glutathione content were significantly improved (P < 0.05. Conversely, anti-superoxide anion, glutathione reducase and glutathione peroxidase activities were decreased (P < 0.05 with dietary phosphorus to a certain level. These results indicated that suitable dietary phosphorus improved growth performance, meat quality and muscle antioxidant capacity. Dietary available phosphorus requirement of young grass carp for percentage weight gain was 4.0 g/kg diet.

Constituents from Vigna vexillata and Their Anti-Inflammatory Activity

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Guo-Feng Chen

2012-08-01

Full Text Available The seeds of Vigna genus are important food resources and there have already been many reports regarding their bioactivities. In our preliminary bioassay, the chloroform layer of methanol extracts of V. vexillata demonstrated significant anti-inflammatory bioactivity. Therefore, the present research is aimed to purify and identify the anti-inflammatory principles of V. vexillata. One new sterol (1 and two new isoflavones (2,3 were reported from the natural sources for the first time and their chemical structures were determined by the spectroscopic and mass spectrometric analyses. In addition, 37 known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Among the isolates, daidzein (23, abscisic acid (25, and quercetin (40 displayed the most significant inhibition of superoxide anion generation and elastase release.

Scoparone attenuates RANKL-induced osteoclastic differentiation through controlling reactive oxygen species production and scavenging

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang-Hyun; Jang, Hae-Dong, E-mail: haedong@hnu.kr

2015-02-15

Scoparone, one of the bioactive components of Artemisia capillaris Thunb, has various biological properties including immunosuppressive, hepatoprotective, anti-allergic, anti-inflammatory, and antioxidant effects. This study aims at evaluating the anti-osteoporotic effect of scoparone and its underlying mechanism in vitro. Scoparone demonstrated potent cellular antioxidant capacity. It was also found that scoparone inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and suppressed cathepsin K and tartrate-resistant acid phosphatase (TRAP) expression via c-jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)/p38-mediated c-Fos–nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway. During osteoclast differentiation, the production of general reactive oxygen species (ROS) and superoxide anions was dose-dependently attenuated by scoparone. In addition, scoparone diminished NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 1 (Nox1) expression and activation via the tumor necrosis factor receptor-associated factor 6 (TRAF6)–cSrc–phosphatidylinositol 3-kinase (PI3k) signaling pathway and prevented the disruption of mitochondrial electron transport chain system. Furthermore, scoparone augmented the expression of superoxide dismutase 1 (SOD1) and catalase (CAT). The overall results indicate that the inhibitory effect of scoparone on RANKL-induced osteoclast differentiation is attributed to the suppressive effect on ROS and superoxide anion production by inhibiting Nox1 expression and activation and protecting the mitochondrial electron transport chain system and the scavenging effect of ROS resulting from elevated SOD1 and CAT expression. - Highlights: • Scoparone dose-dependently inhibited RANKL-induced osteoclast differentiation. • Scoparone diminished general ROS and superoxide anions in a dose-dependent manner. • Scoparone inhibited Nox1 expression and

Phosphite radicals and their reactions. Examples of redox, substitution, and addition reactions

International Nuclear Information System (INIS)

Schaefer, K.; Asmus, K.D.

1980-01-01

Phosphite radicals HPO 3 - and PO 3 2 -, which exist in an acid-base equilibrium with pK = 5.75, are shown to take part in various types of reactions. In the absence of scavengers, they disappear mainly by second-order disproportionation and combination; a first-order contribution to the decay is also indicated. HPO 3 - and PO 3 2 - are good reductants toward electron acceptors such as tetranitromethane. In this reaction phosphate and C(NO 2 ) 3 - are formed. Phosphite radicals can, however, also act as good oxidants, e.g., toward thiols and thiolate ions. These reactions lead to the formation of RS. radicals which were identified either directly, as in the case of penicillamine, through the optical absorption of PenS. or more indirectly through equilibration of RS. with RS- to the optically absorbing RSSR-. disulfide radical anion. A homolytic substitution reaction (S/sub H/2) occurs in the reaction of the phosphite radicals with aliphatic disulfides, yielding RS. radicals and phosphate thioester RSPO 3 2 -. Lipoic acid, as an example of a cyclic disulfide, is reduced to the corresponding RSSR-. radical anion and also undergoes the S/sub H/2 reaction with about equal probability. An addition reaction is observed between phosphite radicals and molecular oxygen. The resulting peroxo phosphate radicals establish an acid-base equilibrium HPO 5 - . reversible PO 5 2- . + H+ with a pK = 3.4. Absolute rate constants were determined for all reactions discussed

Superoxide radical and UV irradiation in ultrasound assisted oxidative desulfurization (UAOD): A potential alternative for greener fuels

Science.gov (United States)

Chan, Ngo Yeung

This study is aimed at improving the current ultrasound assisted oxidative desulfurization (UAOD) process by utilizing superoxide radical as oxidant. Research was also conducted to investigate the feasibility of ultraviolet (UV) irradiation-assisted desulfurization. These modifications can enhance the process with the following achievements: (1) Meet the upcoming sulfur standards on various fuels including diesel fuel oils and residual oils; (2) More efficient oxidant with significantly lower consumption in accordance with stoichiometry; (3) Energy saving by 90%; (4) Greater selectivity in petroleum composition. Currently, the UAOD process and subsequent modifications developed in University of Southern California by Professor Yen's research group have demonstrated high desulfurization efficiencies towards various fuels with the application of 30% wt. hydrogen peroxide as oxidant. The UAOD process has demonstrated more than 50% desulfurization of refractory organic sulfur compounds with the use of Venturella type catalysts. Application of quaternary ammonium fluoride as phase transfer catalyst has significantly improved the desulfurization efficiency to 95%. Recent modifications incorporating ionic liquids have shown that the modified UAOD process can produce ultra-low sulfur, or near-zero sulfur diesels under mild conditions with 70°C and atmospheric pressure. Nevertheless, the UAOD process is considered not to be particularly efficient with respect to oxidant and energy consumption. Batch studies have demonstrated that the UAOD process requires 100 fold more oxidant than the stoichiometic requirement to achieve high desulfurization yield. The expected high costs of purchasing, shipping and storage of the oxidant would reduce the practicability of the process. The excess use of oxidant is not economically desirable, and it also causes environmental and safety issues. Post treatments would be necessary to stabilize the unspent oxidant residual to prevent the waste

Sources of superoxide/H2O2 during mitochondrial proline oxidation

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Renata L.S. Goncalves

2014-01-01

Full Text Available p53 Inducible gene 6 (PIG6 encodes mitochondrial proline dehydrogenase (PRODH and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

Chain-end modification of living anionic polybutadiene with diphenylethylenes and styrenes

NARCIS (Netherlands)

Donkers, E.H.D.; Willemse, R.X.E.; Klumperman, B.

2005-01-01

The first step in the transformation of poly(butadienyl)lithium into a macromolecular atom transfer radical polymerization initiator or reversible addition-fragmentation chain transfer agent is the modification of the anionic chain end into a suitable leaving/reinitiating group. We have investigated

The pH dependence of the spectral and anion binding properties of iron containing superoxide dismutase from E. coli B

International Nuclear Information System (INIS)

Fee, J.A.; McClune, G.J.; Lees, A.C.; Zidovetzki, R.; Pecht, I.

1981-01-01

Examination of the optical and EPR properties of the ferric form of the iron containing superoxide dismutase from E.coli B, at pH values ranging from 4.5 to 10.9, has revealed two reversible structural transitions affecting the Fe 3+ ion. The apparent pKsub(a) values of these transitions are 5.1+-0.3 and 9.O+-0.3. The binding of azide has been studied over the pH range 4.5 to 10.7; the affinity of the Fe 3+ for N 3 - is independent of pH from 4.5 to approximately 7.5, after which the dissociation constant decreased by a factor of 10 per unit increase in pH. The apparent pKsub(a) which affects N 3 - binding to the iron is 8.6+-0.2. The association of N 3 - with the iron has been examined using the temperature-jump method at pH 7.4 and 9.3. The kinetics of ligand association were shown to conform to the minimal mechanism: P-Fe 3+ + N 3 - reversible K 1 N 3 - - P-Fe 3+ reversible K 2 P-Fe 3+ - N 3 - . K 1 was found to be essentially unaffected by pH whereas K 2 was much lower at pH 9.3 than at 7.4. The value of K 1 at pH 7.4 (100 M -1 ) corresponds very closely to that obtained for the inhibition constant of azide, 10mM. A scheme is presented in which N 3 - inhibits the iron containing dismutase by competing with O 2 - for an anion binding site near, but not on the Fe 3+ . (author)

The Production of Polycyclic Aromatic Hydrocarbon Anions in Inert Gas Matrices Doped with Alkali Metals. Electronic Absorption Spectra of the Pentacene Anion (C22H14(-))

Science.gov (United States)

Halasinski, Thomas M.; Hudgins, Douglas M.; Salama, Farid; Allamandola, Louis J.; Mead, Susan (Technical Monitor)

1999-01-01

The absorption spectra of pentacene (C22H14) and its radical cation (C22H14(+)) and anion (C22H14(-)) isolated in inert-gas matrices of Ne, Ar, and Kr are reported from the ultraviolet to the near-infrared. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing ion (and counterion) production in the solid matrix. In particular, the formation of isolated pentacene anions is found to be optimized in matrices doped with alkali metal (Na and K).

Antioxidant activity of wild edible plants in the Black Sea Region of Turkey

Energy Technology Data Exchange (ETDEWEB)

Ozen, T.

2010-07-01

The anti oxidative activity of the 80% ethanol extract obtained from eleven commonly consumed wild edible plants was determined according to the phospho molybdenum method, reducing power, metal chelating, superoxide anion and free radical scavenging activity and compared to standard compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox. Total phenolic compounds, flavonoids, and anthocyanins in the extracts were also measured. Trachystemon orientalis, Vaccinium mrytillus, Rumex acetosella Polygonum amphibium, Beta vulgaris, and Similax Excelsa had the highest antioxidant capacities. Overall results showed that these plants can serve as good sources of bioactive polyphenols in the human diet and can be regarded as good candidates for nutritional supplement formulations due to their high concentrations of total phenolic compounds, flavonoids and anthocyanins as well as their strong antioxidant activity. (Author) 42 refs.

Developing a high performance superoxide dismutase based electrochemical biosensor for radiation dosimetry of thallium 201

International Nuclear Information System (INIS)

Salem, Fatemeh; Tavakoli, Hassan; Sadeghi, Mahdi; Riazi, Abbas

2014-01-01

To develop a new biosensor for measurement of superoxide free radical generated in radiolysis reaction, three combinations of SOD-based biosensors including Au/Cys/SOD, Au/GNP/Cys/SOD and Au/GNP/Cys/SOD/Chit were fabricated. In these biosensors Au, GNP, Cys, SOD and Chit represent gold electrode, gold nano-particles, cysteine, superoxide dismutase and chitosan, respectively. For biosensors fabrication, SOD, GNP, Cys and Chit were immobilized at the surface of gold electrode. Cyclic voltametry and chronoamperometry were utilized for evaluation of biosensors performances. The results showed that Au/GNP/Cys/SOD/Chit has significantly better responses compared to Au/Cys/SOD and Au/GNP/Cys/SOD. As a result, this biosensor was selected for dosimetry of ionizing radiation. For this purpose, thallium 201 at different volumes was added to buffer phosphate solution in electrochemical cell. To obtain analytical parameters of Au/GNP/Cys/SOD/Chit, calibration curve was sketched. The results showed that this biosensor has a linear response in the range from 0.5 to 4 Gy, detection limit 0.03 μM. It also has a proper sensitivity (0.6038 nA/Gy), suitable long term stability and cost effective as well as high function for radiation dosimetry. - highlights: • Our biosensor is able to measure produced superoxide radical during water radiolysis. • It has suitable linearity range, good detection limit and long term stability. • It also has proper sensitivity and high performance for low LET ionizing radiation. • The electrochemical method is as good as traditional methods for radiation dosimetry

ESR investigation of the reactions of glutathione, cysteine and penicillamine thiyl radicals: competitive formation of RSOcenter dot, Rcenter dot, RSSRcenter dot-. , and RSScenter dot

Energy Technology Data Exchange (ETDEWEB)

Becker, David; Swarts, Steven; Champagne, Mark; Sevilla, M D

1988-05-01

The reactions of cysteine, glutathione and penicillamine thiyl radicals with oxygen and their parent thiols in frozen solutions have been elucidated with e.s.r. The major sulfur radicals observed are: (1) thiyl radicals, RS center dot; (2) disulfide radical anions, RSSR anion radicals; (3) perthiyl radicals, RSS center dot and upon introduction of oxygen; (4) sulfinyl radicals, RSO center dot, where R represents the remainder of the cysteine, glutathione or penicillamine moiety. The radical product observed depends on pH, concentration of thiol, and presence or absence of molecular oxygen. The sulfinyl radical is a ubiquitous intermediate, peroxyl radical attack on thiols may lead to sulfinyl radicals. The authors elaborate the observed reaction sequences that lead to sulfinyl radicals and, using /sup 17/O isotopic substitution studies, demonstrate the oxygen atom in sulfinyl radicals originates from dissolved molecular oxygen. The glutathione radical is found to abstract hydrogen from the ..cap alpha..-carbon position on the cysteine residue of glutathione to form a carbon-centred radical.

The influence of superoxide dimutase and some other radical scavengers on X-ray resistance, life span and membrane integrity of Sacharomyces cerevisiae

International Nuclear Information System (INIS)

Hartwig, V.

1988-01-01

Evaluations of various strains of yeast showed these to differ widely in the activities of superoxide dimutase and catalase, X-ray sensitivity, reproductive capacity and malondialdehyde concentration. Higher SOD activities in reponse to increases in oxygen production under extreme physiological conditions were observed for the cells of a haploid strain and just as well seen in those of a diploid strain. There were findings pointing to mutually 'compensatory' effects in respect of the contents of CAT and thiol. When intracellular radical scavengers were 'overstrained' by exposure to high X-ray doses, untoward effects on membrane integrity could be detected after irradiation. The use of the SOD-specific inhibitor DDC led to a reduction of both X-ray resistance and life span as a result of SOD-inhibition. Exogenous SOD was seen to reduce the mean life span. Cu 2+ and Mn 2+ were found to have a dual action in that they not only increased the resistance to X-rays through an augmentation of SOD activity but also had an immediate beneficial effect on radioresistance. Exogenous H202 led to an increase in the cellular CAT contents and an enhancement of X-ray resistance. (orig./MG) [de

Comparative studies on extracts from Hericium erinaceus by different polarity reagents to gain higher antioxidant activities.

Science.gov (United States)

Jiang, Shengjuan; Wang, Yuliang; Zhang, Xiaolong

2016-07-01

Hericium erinaceus (H. erinaceus) is a source of exogenous antioxidants that has been traditionally used in China for the prevention and treatment of oxidative stress-associated disease. In the present study, the bioactive compounds of H. erinaceus were extracted with the following eight representative reagents: n-Hexane, xylene, chloroform, anhydrous ether, ethyl acetate, acetone, anhydrous ethanol and distilled water. The in vitro antioxidant activities were also evaluated. All of the extracted compounds exhibited reducing power and scavenging activity against 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion free radicals. In addition, the antioxidant capacities varied with the used chemical reagents and exhibited dose-dependent effects. Extracts from anhydrous ethanol, chloroform and acetone were capable of inhibiting lipid peroxidation. The anhydrous ethanol extracts were observed to have significant levels of antioxidant compounds since they had a strong reducing power, high scavenging rates against DPPH and superoxide anion-free radicals (>90%), and high inhibition rates on lipid peroxidation (>60%). The present study will provide reference data for the antioxidant applications of H. erinaceus in pharmaceutical use and disease prevention.

The effect of orexin-A on cardiac dysfunction mediated by NADPH oxidase-derived superoxide anion in ventrolateral medulla.

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Jun Chen

Full Text Available Hypocretin/orexin-producing neurons, located in the perifornical region of the lateral hypothalamus area (LHA and projecting to the brain sites of rostral ventrolateral medulla (RVLM, involve in the increase of sympathetic activity, thereby regulating cardiovascular function. The current study was designed to test the hypothesis that the central orexin-A (OXA could be involved in the cardiovascular dysfunction of acute myocardial infarction (AMI by releasing NAD(PH oxidase-derived superoxide anion (O2 (- generation in RVLM, AMI rat model established by ligating the left anterior descending (LAD coronary artery to induce manifestation of cardiac dysfunction, monitored by the indicators as heart rate (HR, heart rate variability (HRV, mean arterial pressure (MAP and left intraventricular pressure. The results showed that the expressions of OXA in LHA and orexin 1 receptor (OX1R increased in RVLM of AMI rats. The double immunofluorescent staining indicated that OX1R positive cells and NAD(PH oxidative subunit gp91phox or p47phox-immunoreactive (IR cells were co-localized in RVLM. Microinjection of OXA into the cerebral ventricle significantly increased O2 (- production and mRNA expression of NAD(PH oxidase subunits when compared with aCSF-treated ones. Exogenous OXA administration in RVLM produced pressor and tachycardiac effects. Furthermore, the antagonist of OX1R and OX2R (SB-408124 and TCS OX2 29, respectively or apocynin (APO, an inhibitor of NAD(PH oxidase, partly abolished those cardiovascular responses of OXA. HRV power spectral analysis showed that exogenous OXA led to decreased HF component of HRV and increased LF/HF ratio in comparison with aCSF, which suggested that OXA might be related to sympathovagal imbalance. As indicated by the results, OXA might participate in the central regulation of cardiovascular activities by disturbing the sympathovagal balance in AMI, which could be explained by the possibility that OXR and NAD(PH-derived O

Polydatin attenuates d-galactose-induced liver and brain damage through its anti-oxidative, anti-inflammatory and anti-apoptotic effects in mice.

Science.gov (United States)

Xu, Lie-Qiang; Xie, You-Liang; Gui, Shu-Hua; Zhang, Xie; Mo, Zhi-Zhun; Sun, Chao-Yue; Li, Cai-Lan; Luo, Dan-Dan; Zhang, Zhen-Biao; Su, Zi-Ren; Xie, Jian-Hui

2016-11-09

Accumulating evidence has shown that chronic injection of d-galactose (d-gal) can mimic natural aging, with accompanying liver and brain injury. Oxidative stress and apoptosis play a vital role in the aging process. In this study, the antioxidant ability of polydatin (PD) was investigated using four established in vitro systems. An in vivo study was also conducted to investigate the possible protective effect of PD on d-gal-induced liver and brain damage. The results showed that PD had remarkable in vitro free radical scavenging activity on 2,2-diphenyl-1-picryl-hydrazyl (DPPH˙), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS + ˙) radical ions, and hydroxyl and superoxide anions. Results in vivo indicated that, in a group treated with d-gal plus PD, PD remarkably decreased the depression of body weight and organ indexes, reduced the levels of the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and alleviated alterations in liver and brain histopathology. PD also significantly decreased the level of MDA and elevated SOD, GSH-Px, CAT activity and T-AOC levels in the liver and brain. In addition, the levels of inflammatory mediators, such as TNF-α, IL-1β and IL-6 in serum were markedly reduced after PD treatment. Western blotting results revealed that PD treatment noticeably attenuated the d-gal-induced elevation of Bcl-2/Bax ratio and caspase-3 protein expression in liver and brain. Overall, our findings indicate that PD treatment could effectively attenuate d-gal-induced liver and brain damage, and the mechanism might be associated with decreasing the oxidative stress, inflammation and apoptosis caused by d-gal. PD holds good potential for further development into a promising pharmaceutical candidate for the treatment of age-associated diseases.

Superoxide scavenging activity of pirfenidone-iron complex

International Nuclear Information System (INIS)

Mitani, Yoshihiro; Sato, Keizo; Muramoto, Yosuke; Karakawa, Tomohiro; Kitamado, Masataka; Iwanaga, Tatsuya; Nabeshima, Tetsuji; Maruyama, Kumiko; Nakagawa, Kazuko; Ishida, Kazuhiko; Sasamoto, Kazumi

2008-01-01

Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O 2 ·- ) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of O 2 ·- produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O 2 ·- released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O 2 ·- scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis

The suppression of manganese superoxide dismutase decreased the survival of human glioblastoma multiforme T98G cells

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Novi S. Hardiany

2017-05-01

Full Text Available Background: Glioblastoma multiforme (GBM is a primary malignant brain tumor which has poor prognosis. High incidence of oxidative stress-based therapy resistance could be related to the high antioxidant status of GBM cells. Our previous study has reported that manganese superoxide dismutase (MnSOD antioxidant expression was significantly higher in high grade glioma than in low grade. The aim of this study was to analyze the impact of MnSOD suppression toward GBM cell survival.Methods: This study is an experimental study using human glioblastoma multiforme T98G cell line. Suppression of MnSOD expression was performed using in vitro transfection MnSOD-siRNA. The MnSOD expression was analyzed by measuring the mRNA using real time RT-PCR, protein using ELISA technique, and specific activity of enzyme using inhibition of xantine oxidase. Concentration of reactive oxygen species (ROS intracellular was determined by measuring superoxide radical and hydrogen peroxide. Cell survival was analyzed by measuring viability, proliferation, and cell apoptosis.Results: In vitro transfection of MnSOD-siRNA suppressed the mRNA, protein, and specific activity of MnSOD. This treatment significantly increased the concentration of superoxide radical; however, it did not influence the concentration of hydrogen peroxide. Moreover, viability MnSOD-suppressing cell significantly decreased, accompanied by increase of cell apoptosis without affecting cell proliferation.Conclusion: The suppression of MnSOD expression leads to decrease glioblastoma multiforme cell survival, which was associated to the increase of cell apoptotic.

Radiolysis study of the oxidation of a vitamin K model compound in ethanolic solution

International Nuclear Information System (INIS)

Fackir, L.; Jore, D.; Gardes-Albert, M.; Ferradini, C.; Acher, F.; Azerad, R.

1993-01-01

It seems that the biological action of vitamin K (with its important role in carboxylating processes) may involve monoelectronic exchanges. Therefore radical mechanisms of a vitamin K model molecule KHp have been studied in ethanolic solution by mean of steady state radiolysis method. The oxidation of KHp by H 3 C-CH(OH)OO . model peroxyl radicals leads to the formation of a 'dimeric' form of vitamin K. The superoxide anions seem not to be reactive towards KHp in the chosen irradiation conditions

Direct Comparison of the Enzymatic Characteristics and Superoxide Production of the Four Aldehyde Oxidase Enzymes Present in Mouse.

Science.gov (United States)

Kücükgöze, Gökhan; Terao, Mineko; Garattini, Enrico; Leimkühler, Silke

2017-08-01

Aldehyde oxidases (AOXs) are molybdoflavoenzymes with an important role in the metabolism and detoxification of heterocyclic compounds and aliphatic as well as aromatic aldehydes. The enzymes use oxygen as the terminal electron acceptor and produce reduced oxygen species during turnover. Four different enzymes, mAOX1, mAOX3, mAOX4, and mAOX2, which are the products of distinct genes, are present in the mouse. A direct and simultaneous comparison of the enzymatic properties and characteristics of the four enzymes has never been performed. In this report, the four catalytically active mAOX enzymes were purified after heterologous expression in Escherichia coli The kinetic parameters of the four mouse AOX enzymes were determined and compared with the use of six predicted substrates of physiologic and toxicological interest, i.e., retinaldehyde, N 1 -methylnicotinamide, pyridoxal, vanillin, 4-(dimethylamino)cinnamaldehyde ( p- DMAC), and salicylaldehyde. While retinaldehyde, vanillin, p- DMAC, and salycilaldehyde are efficient substrates for the four mouse AOX enzymes, N 1 -methylnicotinamide is not a substrate of mAOX1 or mAOX4, and pyridoxal is not metabolized by any of the purified enzymes. Overall, mAOX1, mAOX2, mAOX3, and mAOX4 are characterized by significantly different K M and k cat values for the active substrates. The four mouse AOXs are also characterized by quantitative differences in their ability to produce superoxide radicals. With respect to this last point, mAOX2 is the enzyme generating the largest rate of superoxide radicals of around 40% in relation to moles of substrate converted, and mAOX1, the homolog to the human enzyme, produces a rate of approximately 30% of superoxide radicals with the same substrate. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Antioxidant Properties of Berberis aetnensis C. Presl (Berberidaceae Roots Extract and Protective Effects on Astroglial Cell Cultures

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Agata Campisi

2014-01-01

Full Text Available Berberis aetnensis C. Presl (Berberidaceae is a bushy-spiny shrub common on Mount Etna (Sicily. We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

Antioxidant properties of Berberis aetnensis C. Presl (Berberidaceae) roots extract and protective effects on astroglial cell cultures.

Science.gov (United States)

Campisi, Agata; Acquaviva, Rosaria; Bonfanti, Roberta; Raciti, Giuseppina; Amodeo, Andrea; Mastrojeni, Silvana; Ragusa, Salvatore; Iauk, Liliana

2014-01-01

Berberis aetnensis C. Presl (Berberidaceae) is a bushy-spiny shrub common on Mount Etna (Sicily). We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

Evaluation of radical scavenging activity, intestinal cell viability and antifungal activity of Brazilian propolis by-product.

Science.gov (United States)

de Francisco, Lizziane; Pinto, Diana; Rosseto, Hélen; Toledo, Lucas; Santos, Rafaela; Tobaldini-Valério, Flávia; Svidzinski, Terezinha; Bruschi, Marcos; Sarmento, Bruno; Oliveira, M Beatriz P P; Rodrigues, Francisca

2018-03-01

Propolis is a natural adhesive resinous compound produced by honeybees to protect hives from bacteria and fungi, being extremely expensive for food industry. During propolis production, a resinous by-product is formed. This resinous waste is currently undervalued and underexploited. Accordingly, in this study the proximate physical and chemical quality, as well as the antioxidant activity, radical scavenging activity and cell viability of this by-product were evaluated and compared with propolis in order to boost new applications in food and pharmaceutical industries. The results revealed that the by-product meets the physical and chemical quality standards expected and showed that the propolis waste contains similar amounts of total phenolic content (TPC) and total flavonoid content (TFC) to propolis. Also, a good scavenging activity against reactive oxygen and nitrogen species (ROS and RNS, respectively) determined by the assays of superoxide anion radical (O 2 - ), hydrogen peroxide (H 2 O 2 ), hypochlorous acid (HOCl), nitric oxide (NO) and peroxyl radical (ROO) were determined. Linear positive correlations were established between the TPC of both samples and the antioxidant activity evaluated by three different methods (DPPH, ABTS and FRAP assays). The extracts were also screened for cell viability assays in two different intestinal cell lines (HT29-MTX and Caco-2), showing a viability concentration-dependent. Similarly, the Artemia salina assay, used to assess toxicity, demonstrated the concentration influence on results. Finally, the antifungal activity against ATCC species of Candida was demonstrated. These results suggest that propolis by-product can be used as a new rich source of bioactive compounds for different areas, such as food or pharmaceutical. Copyright © 2017 Elsevier Ltd. All rights reserved.

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals.

Science.gov (United States)

Oliveira, Ivo; Coelho, Valentim; Baltasar, Raquel; Pereira, José Alberto; Baptista, Paula

2009-07-01

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin-Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS-NADH-nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC(50) 232.7 microg/mL) and DPPH scavenging effect (IC(50) 63.2 microg/mL) followed by water extracts (with IC(50) of 287.7 and 73.7 microg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC(50) 6.9 microg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.

Superoxide Dismutase as a Tool for the Mulacular Identification of Plant Parasitic Nematodes

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S. Molinari

2004-08-01

Full Text Available Superoxide dismutase (SOD is a constitutive family of enzymes produced by all aerobic organisms. Varying amounts of SOD activity have been found at all life stages of the most diffused plant parasitic nematodes. SOD is important to aerobic metabolism and parasitism of nematodes in that it catalyzes the first step of the neutralization of the highly toxic superoxide anion (O2 •-, which is largely produced in plant-nematode incompatible reactions. SOD has also been shown to be a significant tool to diagnose root-knot, cyst-, and longidorid nematodes. A high SOD polymorphism has been revealed by Native-Page on gradient polyacrylamide gels for Meloidogyne spp. and by isoelectrofocusing for Globodera, Xiphinema and Longidorus spp. The sensitivity of such procedures has been improved by using the PhastSystem (Amersham Biosciences, Piscata, NJ, USA, an automated equipment for electrophoresis. An accurate discrimination of species of all the nematode genera tested has been achieved and an attempt was made to group populations of the Xiphinema americanum-group and to detect Globodera rostochiensis and G. pallida pathotypes.

Preparation of Cationic MOFs with Mobile Anions by Anion Stripping to Remove 2,4-D from Water

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Tao Chen

2017-07-01

Full Text Available A cationic porous framework with mobile anions (MIL-101(Cr-Cl was easily and successfully synthesized by utilizing the stronger affinity of F− to Al3+ than Cr3+ in the charge-balanced framework of MIL-101(Cr. The structure, morphology and porosity of MIL-101(Cr-Cl were characterized. The obtained new materials retain the high surface area, good thermostability, and structure topology of MIL-101(Cr. With the mobile Cl− anion, MIL-101(Cr-Cl can be used as an ion-exchange material for anionic organic pollutions. In this work, 2,4-dichlorophenoxyacetic acid (2,4-D was used as a model to test the absorption performance of this new material. This new material exhibited improved adsorbability compared to that of the original metal-organic frameworks (MOFs. At the same time, this material also shows high anti-interference performance with changing solution pH.

Dual-Ratiometric Fluorescent Nanoprobe for Visualizing the Dynamic Process of pH and Superoxide Anion Changes in Autophagy and Apoptosis.

Science.gov (United States)

Yang, Limin; Chen, Yuanyuan; Yu, Zhengze; Pan, Wei; Wang, Hongyu; Li, Na; Tang, Bo

2017-08-23

Autophagy and apoptosis are closely associated with various pathological and physiological processes in cell cycles. Investigating the dynamic changes of intracellular active molecules in autophagy and apoptosis is of great significance for clarifying their inter-relationship and regulating mechanism in many diseases. In this study, we develop a dual-ratiometric fluorescent nanoprobe for quantitatively differentiating the dynamic process of superoxide anion (O 2 •- ) and pH changes in autophagy and apoptosis in HeLa cells. A rhodamine B-loaded mesoporous silica core was used as the reference, and fluorescence probes for pH and O 2 •- measurement were doped in the outer layer shell of SiO 2 . Then, chitosan and triphenylphosphonium were modified on the surface of SiO 2 . The experimental results showed that the nanoprobe is able to simultaneously and precisely visualize the changes of mitochondrial O 2 •- and pH in HeLa cells. The kinetics data revealed that the changes of pH and O 2 •- during autophagy and apoptosis in HeLa cells were significantly different. The pH value was decreased at the early stage of apoptosis and autophagy, whereas the O 2 •- level was enhanced at the early stage of apoptosis and almost unchanged at the initial stage of autophagy. At the late stage of apoptosis and autophagy, the concentration of O 2 •- was increased, whereas the pH was decreased at the late stage of autophagy and almost unchanged at the late stage of apoptosis. We hope that the present results provide useful information for studying the effects of O 2 •- and pH in autophagy and apoptosis in various pathological conditions and diseases.

Photoactivation of isoflavonoid phytoalexins: involvement of free radicals

International Nuclear Information System (INIS)

Bakker, J.; Gommers, F.J.; Smits, L.; Fuchs, A.; Vries, F.W. de

1983-01-01

Ultraviolet irradiation of isoflavonoid phytoalexins phaseollin, 3.6a. 9-trihydroxypterocarpan, glyceollin, tuberosin and pisatin, but not medicarpin, brought about inactivation of glucose-6-phosphate dehydrogenase in an in vitro assay system. Photoinactivation of the enzyme by photoactivated pisatin in air-saturated solutions was hardly affected by singlet oxygen quenchers such as NaN 3 , bovine serum albumin, histidine or methionine. Neither addition of the hydroxyl radical scavengers mannitol, Na-benzoate and ethanol nor the presence of catalase or superoxide dismutase protected the enzyme against photoinactivation, suggesting that OHradical, H 2 O 2 and O 2 radical are not the reactive oxygen species involved. However, the free radical scavenger S-(2-amino-ethyl)isothiouronium bromide hydrobromide (AET) protected the enzyme against inactivation by photoactivated pisatin. Direct evidence for the generation of free radicals was obtained by ESR measurements of solutions of phaseollin, pisatin and medicarpin in hexane irradiated with ultraviolet light in the presence or absence of O 2 . Phaseollin produced the most stable free radicals, whereas medicarpin hardly gave rise to free radical formation; pisatin took a somewhat intermediate position by producing a strong ESR signal which, however, decayed rather quickly. These results indicate free radical formation as the cause for photoinactivation of enzymes by photoactivated isoflavonoid phytoalexins. (author)

Mulliken-Hush elucidation of the encounter (precursor) complex in intermolecular electron transfer via self-exchange of tetracyanoethylene anion-radical

International Nuclear Information System (INIS)

Rosokha, S.V.; Newton, M.D.; Head-Gordon, M.; Kochi, J.K.

2006-01-01

The paramagnetic [1:1] encounter complex (TCNE) 2 -dot is established as the important precursor in the kinetics and mechanism of electron-transfer for the self-exchange between tetracyanoethylene acceptor (TCNE) and its radical-anion as the donor. Spectroscopic observation of the dimeric complex (TCNE) 2 -dot by its intervalence absorption band at the solvent-dependent wavelength of λ IV ∼1500nm facilitates the application of Mulliken-Hush theory which reveals the significant electronic interaction extant between the pair of cofacial TCNE moieties with the sizable coupling of H DA =1000cm -1 . The transient existence of such an encounter complex provides the critical link in the electron-transfer kinetics by lowering the classical Marcus reorganization barrier by the amount of H DA in this strongly adiabatic system. Ab initio quantum-mechanical methods as applied to independent theoretical computations of both the reorganization energy (λ) and the electronic coupling element (H DA ) confirm the essential correctness of the Mulliken-Hush formalism for fast electron transfer via strongly coupled donor/acceptor encounter complexes

Metalloantibiotic Mn(II)-bacitracin complex mimicking manganese superoxide dismutase

International Nuclear Information System (INIS)

Piacham, Theeraphon; Isarankura-Na-Ayudhya, Chartchalerm; Nantasenamat, Chanin; Yainoy, Sakda; Ye Lei; Buelow, Leif; Prachayasittikul, Virapong

2006-01-01

Superoxide dismutase (SOD) activities of various metallobacitracin complexes were evaluated using the riboflavin-methionine-nitro blue tetrazolium assay. The radical scavenging activity of various metallobacitracin complexes was shown to be higher than those of the negative controls, e.g., free transition metal ions and metal-free bacitracin. The SOD activity of the complex was found to be in the order of Mn(II) > Cu(II) > Co(II) > Ni(II). Furthermore, the effect of bacitracin and their complexation to metals on various microorganisms was assessed by antibiotic susceptibility testing. Moreover, molecular modeling and quantum chemical calculation of the metallobacitracin complex was performed to evaluate the correlation of electrostatic charge of transition metal ions on the SOD activity

Radicals of DNA and DNA nucleotides generated by ionising radiation

International Nuclear Information System (INIS)

Przybytniak, G.

2004-01-01

A first stage of cell processes leading to DNA damage of initiated by radical reactions. In a model system such transformations were generated by ionising radiation which involves production of electron loss and electron gain centers of the substrate and radical formation. Using cryogenic ESR spectroscopy it was found that the DNA nucleotides, which convert to radical anions upon electron capture undergo the separation of unpaired spin and charge due to protonation. Circular and linear dichroism studies enabled to conclude that iron ions(III) induce strong changes in the DNA helical structure indicating their coordination with nitrogen bases. The repair of DNA radicals produced via radiolytic oxidation, i.e. the guanine radical cation and the allyl type radical of thymine, is possible at elevated temperatures due to the involvement of sulphydryl groups. The influence of the thiol charge is then limited

Quantum Chemical Investigation on the Antioxidant Activity of Neutral and Anionic Forms of Juglone: Metal Chelation and Its Effect on Radical Scavenging Activity

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Aymard Didier Fouegue Tamafo

2017-01-01

Full Text Available The chelation ability of divalent Mg, Ca, Fe, Co, Ni, Cu, Zn, and monovalent Cu ions by neutral and anionic forms of juglone has been investigated at DFT/B3LYP/6-31+G(d,p level of theory in gas and aqueous phases. It is noteworthy that only the 1 : 1 stoichiometry was considered herein. The effects of these metals on the radical scavenging activity of neutral juglone were evaluated via the usual descriptors of hydrogen atom transfer. According to our results, metal chelation by the two forms of juglone was spontaneous and exothermic in both media. Based on the binding energies, Cu(II ion showed the highest affinity for the ligands. QTAIM analyses identified the metal-ligand bonds as intermediate type interactions in all the chelates, except those of Ca and Mg. It was also found that the chelates were better radical scavengers than the ligands. In the gas phase, the scavenging activity of the compounds was found to be governed by direct hydrogen atom transfer, the Co(II chelate being the most reactive. In the aqueous phase also, the sequential proton loss electron transfer was preferred by all the molecules, while the Cu(II chelates were the most reactive.

An alternative anionic bio-sustainable anti-fungal agent: Investigation of its mode of action on the fungal cell membrane.

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Stenbæk, Jonas; Löf, David; Falkman, Peter; Jensen, Bo; Cárdenas, Marité

2017-07-01

The potential of a lactylate (the sodium caproyl lactylate or C10 lactylate), a typical food grade emulsifier, as an anionic environmental friendly anti-fungal additive was tested in growth medium and formulated in a protective coating for exterior wood. Different laboratory growth tests on the blue stain fungus Aureobasidium pullulans were performed and its interactions on a model fungal cell membrane were studied. Promising short term anti-fungal effects in growth tests were observed, although significant but less dramatic effects took place in coating test on wood panels. Scanning electron microscope analysis shows clear differences in the amount of fungal slime on the mycelium of Aureobasidium pullulans when the fungus was exposed of C10 lactylate. This could indicate an effect on the pullulan and melanin production by the fungus. Moreover, the interaction studies on model fungal cell membranes show that C10 lactylate affects the phospholipid bilayer in a similar manner to other negative charged detergents. Copyright © 2017 Elsevier Inc. All rights reserved.

Purification and properties of Cu-Zn superoxide dismutase extracted from Brucella abortus strain 19

Energy Technology Data Exchange (ETDEWEB)

Tabatabai, L.B. (ARS-USDA, Ames, IA (United States))

1991-03-11

Recent work showed that a recombinant 20 kDa protein from Brucella abortus expressed in E. coli is a Cu-Zn superoxide dismutase (SOD). Western blot and ELISA results indicated that cattle with brucellosis have antibody to SOD. Here the authors report the purification and properties of the native B. abortus Cu-Zn SOD. SOD was extracted from methanol-killed Brucella abortus strain 19 with 0.1 M sodium citrate-1.0 M sodium chloride solution. The extract was dialyzed and protein precipitated by ammonium sulfate at 70-100% saturation was collected. The SOD was purified by HPLC anion exchange chromatography. SOD activity was assayed with a coupled enzyme assay using xanthine oxidase-cytochrome C reduction assay. The authors determined that the Brucella SOD is present in two molecular forms both inhibitable with KCN with Ki's of 0.32 mM and 4.98 mM, respectively. No other form of SOD was identified in the extract. Polyclonal antibody to SOD and polyclonal antibody to SOD synthetic peptide residues 134-143 inhibited SOD activity by 50% and 13%, respectively. Both SOD and the synthetic peptide inhibited binding of anti-SOD antibody to SOD by 60% and 20%, respectively. Based on these results the SOD and its amphipathic peptide will be considered as candidates for the design of synthetic multiple peptide vaccines and diagnostic reagents for bovine brucellosis.

Dynamics of gas-phase transient species studied by dissociative photodetachment of molecular anions

OpenAIRE

Lu, Zhou

2007-01-01

Gas-phase transient species, such as the CH₃CO₂ and HOCO free radicals, play important roles in combustion and environment chemistry. In this thesis work, the dynamics of these two radicals were studied by dissociative photodetachment (DPD) of the negative ions, CH₃CO₂-С and HOCO⁻, respectively. The experiments were carried out with a fast-ion-beam photoelectron-photofragment coincidence (PPC) spectrometer. Mass-selected molecular anions in a fast ion beam were intercepted by a linearly polar...

A Computational Study of Structure and Reactivity of N-Substitued-4-Piperidones Curcumin Analogues and Their Radical Anions

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Maximiliano Martínez-Cifuentes

2016-12-01

Full Text Available In this work, a computational study of a series of N-substitued-4-piperidones curcumin analogues is presented. The molecular structure of the neutral molecules and their radical anions, as well as their reactivity, are investigated. N-substituents include methyl and benzyl groups, while substituents on the aromatic rings cover electron-donor and electron-acceptor groups. Substitutions at the nitrogen atom do not significantly affect the geometry and frontier molecular orbitals (FMO energies of these molecules. On the other hand, substituents on the aromatic rings modify the distribution of FMO. In addition, they influence the capability of these molecules to attach an additional electron, which was studied through adiabatic (AEA and vertical electron affinities (VEA, as well as vertical detachment energy (VDE. To study electrophilic properties of these structures, local reactivity indices, such as Fukui (f+ and Parr (P+ functions, were calculated, and show the influence of the aromatic rings substituents on the reactivity of α,β-unsaturated ketones towards nucleophilic attack. This study has potential implications for the design of curcumin analogues based on a 4-piperidone core with desired reactivity.

Protective effect of 3,4-dihydroxybenzoic acid isolated from Cladophora wrightiana Harvey against ultraviolet B radiation-induced cell damage in human HaCaT keratinocytes.

Science.gov (United States)

Cha, Ji Won; Piao, Mei Jing; Kim, Ki Cheon; Zheng, Jian; Yao, Cheng Wen; Hyun, Chang Lim; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Lee, Nam Ho; Ko, Mi Hee; Hyun, Jin Won

2014-03-01

The aim of the present study was to elucidate the protective properties of 3,4-dihydroxybenzoic acid (DBA) isolated from Cladophora wrightiana Harvey (a green alga) against ultraviolet B (UVB)-induced damage to human HaCaT keratinocytes. DBA exhibited scavenging actions against the 1,1-diphenyl-2-picrylhydrazyl radical, the superoxide anion, and the hydroxyl radical. Furthermore, DBA decreased the levels of intracellular reactive oxygen species generated by hydrogen peroxide or UVB treatment of the cells. DBA also decreased the UVB-augmented levels of phospho-histone H2A.X and the extent of comet tail formation, which are both indications of DNA damage. In addition, the compound safeguarded keratinocytes from UVB-induced injury by reversing the production of apoptotic bodies, overturning the disruption of mitochondrial membrane potential, increasing the expression of the anti-apoptotic protein, B-cell lymphoma 2, and decreasing the expression of the pro-apoptotic proteins, Bcl-2-associated X and cleaved caspase-3. Taken together, these results demonstrate that DBA isolated from a green alga protects human keratinocytes against UVB-induced oxidative stress and apoptosis.

COMPARISON OF SELECTIVE AND NON SELECTIVE CYCLO-OXYGENASE 2 INHIBITORS IN EXPERIMENTAL COLITIS EXACERBATION: role of leukotriene B4 and superoxide dismutase

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José Wander BREGANÓ

2014-09-01

Full Text Available Context Nonsteroidal anti-inflammatory drugs are considered one of the most important causes of reactivation of inflammatory bowel disease. With regard to selective cyclo-oxygenase 2 inhibitors, the results are controversial in experimental colitis as well as in human studies. Objectives The aim this study is to compare nonsteroidal anti-inflammatory drugs effects, selective and non selective cyclo-oxygenase 2 inhibitors, in experimental colitis and contribute to the understanding of the mechanisms which nonsteroidal anti-inflammatory drugs provoke colitis exacerbation. Methods Six groups of rats: without colitis, with colitis, and colitis treated with celecoxib, ketoprofen, indometacin or diclofenac. Survival rates, hemoglobin, plasmatic albumin, colonic tissue of interleukin-1ß, interleukin-6, tumor necrosis factor alpha, prostaglandin E2, catalase, superoxide dismutase, thiobarbituric acid-reactive substances, chemiluminescence induced by tert-butil hydroperoxides, and tissue and plasmatic leukotriene B4 were determined. Results The groups treated with diclofenac or indometacin presented lower survival rates, hemoglobin and albumin, higher tissue and plasmatic leukotriene B4 and tissue superoxide dismutase than the group treated with celecoxib. Ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib, concerning to survival rate and albumin. The groups without colitis, with colitis and with colitis treated with celecoxib showed leukotriene B4 and superoxide dismutase lower levels than the groups treated with nonselective cyclo-oxygenase 2 inhibitors. Conclusions Diclofenac and indometacin presented the highest degree of induced colitis exacerbation with nonsteroidal anti-inflammatory drugs, celecoxib did not show colitis exacerbation, and ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib. These results suggest that leukotriene B4 and superoxide dismutase can be

Co-Immobilization of Superoxide Dismutase with Catalase on Soft Microparticles Formed by Self-Assembly of Amphiphilic Poly(Aspartic Acid

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Siyu Mao

2017-07-01

Full Text Available Through genetic engineering technology, catalase (CAT and superoxide dismutase (SOD have been separately fused to an elastin-like polypeptide (ELP. Thus, the enzymes can be purified through phase transition. Hexadecylamine-modified poly(aspartic acid (HPASP is able to self-assemble, forming soft microparticles. The HPASP microparticles were used to co-immobilize SOD-ELP and CAT-ELP through amidation reaction. Circular dichroism (CD confirmed that the secondary structures of the co-immobilized enzymes have been preserved. Fluorescence spectra showed that the co-immobilized enzymes exhibited a higher stability than the free enzymes. Dismutation of superoxide by superoxide dismutase (SOD generates hydrogen peroxide. By using the co-immobilized enzymes (SOD-ELP/CAT-ELP@HPASP, the generated hydrogen peroxide of SOD-ELP can be decomposed in situ by CAT-ELP. Activity assay results demonstrated that the superoxide anion (•O2− scavenging ability is 63.15 ± 0.75% for SOD-ELP/CAT-ELP@HPASP. The advantages of the approach of enzyme co-immobilization include the fact that the soft support HPASP itself is a polypeptide in nature, the stability of immobilized enzymes is improved, and a high activity has been achieved. Potentially SOD-ELP/CAT-ELP@HPASP can be applied in the cosmetic industry.

Uptake of NO-releasing drugs by the P2 nucleoside transporter in trypanosomes

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L. Soulère

1999-11-01

Full Text Available Nitric oxide (NO· has been identified as a principal regulatory molecule of the immune system and the major cytotoxic mediator of activated immune cells. NO· can also react rapidly with a variety of biological species, particularly with the superoxide radical anion O2·- at almost diffusion-limited rates to form peroxynitrite anion (ONOO-. ONOO- and its proton-catalyzed decomposition products are capable of oxidizing a great diversity of biomolecules and can act as a source of toxic hydroxyl radicals. As a consequence, a strategy for the development of molecules with potential trypanocidal activities could be developed to increase the concentration of nitric oxide in the parasites through NO·-releasing compounds. In this way, the rate of formation of peroxynitrite from NO· and O2·- would be faster than the rate of dismutation of superoxide radicals by superoxide dismutases which constitute the primary antioxidant enzymatic defense system in trypanosomes. The adenosine transport systems of parasitic protozoa, which are also in certain cases implicated in the selective uptake of active drugs such as melarsoprol or pentamidine, could be exploited to specifically target these NO·-releasing compounds inside the parasites. In this work, we present the synthesis, characterization and biological evaluation of a series of molecules that contain both a group which would specifically target these drugs inside the parasites via the purine transporter, and an NO·-donor group that would exert a specific pharmacological effect by increasing NO level, and thus the peroxynitrite concentration inside the parasite.

Free radicals from irradiated lyophilized DNA: influence of water of hydration

International Nuclear Information System (INIS)

Huettermann, J.; Roehrig, M.; Koehnlein, W.

1992-01-01

Lyophilized DNA equilibrated with water vapour at various relative humidities (0-95% H 2 O or D 2 O) was X-irradiated at 77 K and analysed for free radicals by electron paramagnetic resonance (EPR) spectroscopy in the temperature range 77-280 K. Analysis of spectra according to variation in humidity, microwave power and temperature generally yielded a doublet and a triplet spectrum at 77 K. The doublet partially converted into the 5-thymyl radical (TH . ). DNA containing deuterated thymine (dTDNA) revealed that the doublet of ''normal'' DNA should be composed of two similar doublets, one of which should be assigned to the thymine anion, the other possibly the cytosine anion. The triplet signal was more stable and could be related to the guanine cation or its deprotonated successor. Several other patterns were detected among them an allyl radical in highly aquated DNA (95% humidity). Other features occurred either predominantly or exclusively in DNA equilibrated above 66% relative humidity and were ascribed to an influence of the secondary structure. (author)

Preparation of Acrylamide-based Anionic Polyelectrolytes for Soil Establishment

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Ahmad Rabiee

2012-12-01

Full Text Available Synthetic water soluble acrylamide-based polymers have wide range of ap-plications  in  the  feld  of  soil  establishment  and  non-desertifcation.  In  this research, the acrylamide-based anionic polyelectrolytes were prepared by  solution polymerization. The polymerization was carried out using AIBN as a radical initiator and at different degrees of anionic charges ranging between 10% and 30% using sodium hydroxide as hydrolyzing agents. The chemical structure of the  synthetic polymers was studied and confrmed by FTIR technique. The charge density on polymer backbone was determined by titration method. The rheological behavior of polymer solutions was evaluated by Brookfeld viscometer. The results show that the viscosity decreases with increasing the shear rate of solutions. Molecular weights of samples were measured by laser light scattering analyzer. The morphology of the polymer was studied by SEM and the EDX was used for elemental analysis determination. The anionic polymers with 10-30% negative charges were mixed with clay in order to evaluate the soil establishment. The results show that an anionic polyelectro-lyte can make soil particles more cohesive and improve soil physical properties.

Skin beautification with oral non-hydrolized versions of carnosine and carcinine: Effective therapeutic management and cosmetic skincare solutions against oxidative glycation and free-radical production as a causal mechanism of diabetic complications and skin aging.

Science.gov (United States)

Babizhayev, Mark A; Deyev, Anatoliy I; Savel'yeva, Ekaterina L; Lankin, Vadim Z; Yegorov, Yegor E

2012-10-01

Advanced glycation Maillard reaction end products (AGEs) are causing the complications of diabetes and skin aging, primarily via adventitious and cross-linking of proteins. Long-lived proteins such as structural collagen are particularly implicated as pathogenic targets of AGE processes. The formation of α-dicarbonyl compounds represents an important step for cross-linking proteins in the glycation or Maillard reaction. The purpose of this study was to investigate the contribution of glycation coupled to the glycation free-radical oxidation reactions as markers of protein damage in the aging of skin tissue proteins and diabetes. To elucidate the mechanism for the cross-linking reaction, we studied the reaction between a three-carbon α-dicarbonyl compound, methylglyoxal, and amino acids using EPR spectroscopy, a spectrophotometric kinetic assay of superoxide anion production at the site of glycation and a chemiluminescence technique. The transglycating activity, inhibition of transition metal ions peroxidative catalysts, resistance to hydrolysis of carnosine mimetic peptide-based compounds with carnosinase and the protective effects of carnosine, carcinine and related compounds against the oxidative damage of proteins and lipid membranes were assessed in a number of biochemical and model systems. A 4-month randomized, double-blind, controlled study was undertaken including 42 subjects where the oral supplement of non-hydrolized carnosine (Can-C Plus® formulation) was tested against placebo for 3 months followed by a 1-month supplement-free period for both groups to assess lasting effects. Assessment of the age-related skin parameters and oral treatment efficacy measurements included objective skin surface evaluation with Visioscan® VC 98 and visual assessment of skin appearance parameters. The results together confirm that a direct one-electron transfer between a Schiff base methylglyoxal dialkylimine (or its protonated form) and methylglyoxal is responsible for

Excimer laser corneal surgery and free oxygen radicals.

Science.gov (United States)

Bilgihan, K; Bilgihan, A; Akata, F; Hasanreisoğlu, B; Türközkan, N

1996-01-01

Corneal photoablation with 193 nm argon fluoride excimer laser is a new technique for the treatment of refractive errors and for removing corneal opacities and irregularities. Ultraviolet radiation and thermal injury induce free radical formation in the tissues. The aim of this study was to confirm the production of free radicals by excimer laser photoablation in rabbits. The thermal changes of the posterior corneal surface were recorded during excimer laser photoablation. The lipid peroxide (LPO) levels and superoxide dismutase (SOD) activities of aqueous humour were measured after excimer laser keratectomy. The aqueous LPO levels were not changed after excimer laser ablation, but both the thermal increase in the cornea during the photoablation and the decreased aqueous SOD activities suggest that free radicals are formed in the cornea during excimer laser keratectomy, and that they may be responsible for some of the complications of excimer laser corneal surgery.

Superoxide radicals mediate heptatoxicity induced by the heat shock protein 90 inhibitors benzoquinone ansamycins

International Nuclear Information System (INIS)

Goldstein, S.

2011-01-01

Complete text of publication follows. Geldanamycin (GM). a benzoquinone ansamycin antibiotic, is a natural product inhibitor of the heat shock protein 90 (Hsp90) with potent and broad anticancer properties. However, its progression to clinical trials was halted due to unacceptable levels of hepatotoxicity. Consequently, numerous less toxic analogs differing only in their 17-substituent have been synthesized including 17-AAG and the water soluble 17-DMAG (Alvespimycin), which have recently entered clinical trials. The different hepatotoxicity induced by GM and its analogs may reflect the redox active properties of the quinone moiety (Q) and possibly the extent of superoxide radical formation, which may stimulate cellular oxidative injury. Q ·- + Q 2 ↔ O 2 ·- + Q. Eq. 1 is established rapidly, and its actual position is governed by E 7 (Q/Q ·- ) and E 7 (O 2 /O 2 ·- ) and the relative concentrations of Q and O 2 . Using pulse radiolysis, E 7 (Q/Q ·- ) for 17-DMAG has been determined vs. O 2 , 1,4-naphthoquinone or menadione to be -194 ± 6 mV, which is somewhat lower than E 7 (O 2 /O 2 ·- ) = -180 mV (1 M O 2 ). Eq. 1 is well to the left in the case of 1,4-benzoquinone and substitution into the ring by electron-donating or -withdrawing groups reduces or increases, respectively, E 7 (Q/Q ·- ) in a predictable manner, e.g. linearly related to the Hammett sigma value of the substituents. Hence, E 7 (Q/Q ·- ) should follow the order GM 2 is more readily reduced to O 2 ·- by GM. It is demonstrated that O 2 ·- can be efficiently trapped by Tempol during the reduction of GM, 17-AAG and 17-DMAG by NADPH catalyzed by NADPH-cytochrome P450 reductase, and that O 2 ·- formation rate, which reflects the rate of NADPH oxidation, follows the order 17-DMAG > GM > 17-AAG. In the absence of O 2 ·- scavengers, the rate of NADPH oxidation follows the order 17-DMAG > 17-AAG > GM. The order of the drug cytotoxicity toward rat primary hepatocytes, as determined by their

In-vitro antioxidant activity of crataeva magna lour. dc bark extract

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Sridhar N

2012-10-01

Full Text Available The plant Crataeva magna belonging to family Capparaceae is used in anti spasmodic, hypotensive, anti-inflammatory, hypoglycemic, anti protozoal, analgesic purposes. The present study was carried out to evaluate appropriate animal model. The antioxidative potential of different solvent extracts of Crataeva magna were evaluated using 1,1-Diphenyl-2-Picrylhydrazyl (DPPH, 2,2 ’-Azino-Bis(3-ethylbenzthiazoline-6-Sulphonic acid (ABTS, superoxide radical, hydroxyl radical, nitric oxide radical scavenging activities and lipid peroxidation inhibition assay. Among those solvent extracts, ethanolic extract of C. magna exhibited highest level of antioxidant activities. The ethanolic extract also inhibited H 2O2 mediated haemolysis and lipid peroxidation in human RBC.

MRP3, an organic anion transporter able to transport anti-cancer drugs

OpenAIRE

Kool, Marcel; van der Linden, Marcel; de Haas, Marcel; Scheffer, George L.; de Vree, J. Marleen L.; Smith, Alexander J.; Jansen, Gerrit; Peters, Godefridus J.; Ponne, Nico; Scheper, Rik J.; Elferink, Ronald P. J. Oude; Baas, Frank; Borst, Piet

1999-01-01

The human multidrug-resistance protein (MRP) gene family contains at least six members: MRP1, encoding the multidrug-resistance protein; MRP2 or cMOAT, encoding the canalicular multispecific organic anion transporter; and four homologs, called MRP3, MRP4, MRP5, and MRP6. In this report, we characterize MRP3, the closest homolog of MRP1. Cell lines were retrovirally transduced with MRP3 cDNA, and new monoclonal antibodies specific for MRP3 were generated. We show that MRP3 is an organic anion ...

Free radicals and lipid peroxidation mediated injury in burn trauma: the role of antioxidant therapy

International Nuclear Information System (INIS)

Horton, Jureta W.

2003-01-01

Burn trauma produces significant fluid shifts that, in turn, reduce cardiac output and tissue perfusion. Treatment approaches to major burn injury include administration of crystalloid solutions to correct hypovolemia and to restore peripheral perfusion. While this aggressive postburn volume replacement increases oxygen delivery to previously ischemic tissue, this restoration of oxygen delivery is thought to initiate a series of deleterious events that exacerbate ischemia-related tissue injury. While persistent hypoperfusion after burn trauma would produce cell death, volume resuscitation may exacerbate the tissue injury that occurred during low flow state. It is clear that after burn trauma, tissue adenosine triphosphate (ATP) levels gradually fall, and increased adenosine monophosphate (AMP) is converted to hypoxanthine, providing substrate for xanthine oxidase. These complicated reactions produce hydrogen peroxide and superoxide, clearly recognized deleterious free radicals. In addition to xanthine oxidase related free radical generation in burn trauma, adherent-activated neutrophils produce additional free radicals. Enhanced free radical production is paralleled by impaired antioxidant mechanisms; as indicated by burn-related decreases in superoxide dismutase, catalase, glutathione, alpha tocopherol, and ascorbic acid levels. Burn related upregulation of inducible nitric oxide synthase (iNOS) may produce peripheral vasodilatation, upregulate the transcription factor nuclear factor kappa B (NF-κB), and promote transcription and translation of numerous inflammatory cytokines. NO may also interact with the superoxide radical to yield peroxynitrite, a highly reactive mediator of tissue injury. Free radical mediated cell injury has been supported by postburn increases in systemic and tissue levels of lipid peroxidation products such as conjugated dienes, thiobarbituric acid reaction products, or malondialdehyde (MDA) levels. Antioxidant therapy in burn therapy

Effect of metal complexation to anti-inflammatory over the action against oxidative and free radicals: ketoprofen action; Efeito da complexacao de metais aos antiinflamatorios na acao contra agentes oxidativos e radicais livres: acao do cetoprofeno

Energy Technology Data Exchange (ETDEWEB)

Manente, Francine Alessandra; Mello, Lucas Rosolen de Almeida; Vellosa, Jose Carlos Rebuglio [UEPG, Universidade Estadual de Ponta Grossa, Departamento de Analises Clinicas eToxicologicas, Ponta Grossa, PR (Brazil); Khalil, Omar Arafat Kdudsi [IFG, Instituto Federal de Goias, Campus de Formosa, Formosa - GO (Brazil); Carvalho, Claudio Teodoro de [UFGD, Universidade Federal da Grande Dourados, Faculdade de Ciencias Exatas e Tecnologias, Dourados-MS (Brazil); Bannach, Gilbert [UNESP, Universidade Estadual Paulista Julio de Mesquita Filho, Faculdade de Ciencias de Bauru, Bauru, SP (Brazil)

2011-07-01

Free radicals are highly reactive species generated in living organisms for the purpose of protection. However, in some circumstances, they are responsible for the occurrence or aggravation of tissue damage. Many anti-inflammatory drugs have a direct effect on free radicals and not radical reactive species, which contributes to its actions against inflammation. Ketoprofen is a nonsteroidal anti-inflammatory agent that generates free radicals by photo irradiation and has an important hemolytic effect with that. The complexation of metals to different drugs has been used as a strategy to improve the pharmacological action of different molecules and reduce their side effects. This paper presents the results of ketoprofen and their metallic complexes action on erythrocytes and free radicals. It was observed that the cerium enhances the scavenger properties of ketoprofen on free radicals, while copper enhances its action over non-radical oxidants. Copper also reduced the hemolytic effect presented by ketoprofen meanwhile its cerium derivative maintained it. (author)

Acyclic diastereoselection in prochiral radical addition to prochiral olefins.

Science.gov (United States)

Sibi, Mukund P; Rheault, Tara R; Chandramouli, Sithamalli V; Jasperse, Craig P

2002-03-27

The stereochemical preference (syn or anti) when prochiral radicals add to prochiral acceptors is of fundamental interest. The primary focus of this research was to determine which factors influence the relative stereochemistry between the beta and gamma chiral centers when these are formed concurrently. While moderate diastereoselectivity was found for addition of alkyl (6a-d) and alpha-alkoxy radicals (16a-c) (15:1 anti). Steric influence in alkyl radical additions was difficult to evaluate due to decreased reactivity when using bulky reaction partners; however, more reactive alpha-alkoxy radicals, it was found that increasing steric bulk leads to moderate increases in selectivity. In addition, higher selectivity was observed when employing lanthanide Lewis acids whose environment (reactivity) was modified using achiral additives, suggesting a potentially simple means for selectivity enhancements in radical reactions. Overall these results indicate that significant stereoelectronic effects are necessary to achieve high levels of selectivity in prochiral radical additions to prochiral acceptors.

A Brief Review on Electro-generated Hydroxyl Radical for Organic Wastewater Mineralization

Directory of Open Access Journals (Sweden)

Ervin Nurhayati

2016-05-01

Full Text Available Hydroxyl radical is a highly reactive oxidizing agent that can be electrochemically generated on the surface of Boron doped diamond (BDD anode. Once generated, this radical will non-selectively mineralize organic pollutants to carbon dioxide, water and organic anions as the oxidation products. Its application in Advanced Oxidation Process (AOP to degrade nonbiodegradable even the recalcitrant pollutants in wastewater has been increasingly studied and even applied.

Potential repair of free radical adducts of dGMP and dG by a series of reductants. A pulse radiolytic study

International Nuclear Information System (INIS)

O'Neill, P.; Chapman, P.W.

1985-01-01

Using the technique of pulse radiolysis, it has been demonstrated that the interaction of hydroxyl-radical adducts of dG and dGMP with a series of reductants with different oxidation potentials at pH 7.0-7.4 proceeds via an electron transfer process (k approx. 1.4-34 x 10 8 dm 3 mol -1 s -1 ). The one-electron oxidation of dGMP (dG) by Br2-anion radicals was shown to result in the formation of a species, the properties of which are similar to those of the OH-radical adduct of dGMP with oxidizing properties based upon both spectral and kinetic information. The nature of the dGMP species produced on interaction with Br2-anion radicals to produce specific base damage. The implications of these findings are presented in terms of potential free radical repair of hydroxyl radical damage and of synergistic effects whereby one reductant may be regenerated at the expense of another reductant. (author)

Nitroxyl Modified Tobacco Mosaic Virus as a Metal-Free High-Relaxivity MRI and EPR Active Superoxide Sensor.

Science.gov (United States)

Dharmarwardana, Madushani; Martins, André F; Chen, Zhuo; Palacios, Philip M; Nowak, Chance M; Welch, Raymond P; Li, Shaobo; Luzuriaga, Michael A; Bleris, Leonidas; Pierce, Brad S; Sherry, A Dean; Gassensmith, Jeremiah J

2018-05-29

Superoxide overproduction is known to occur in multiple disease states requiring critical care; yet, noninvasive detection of superoxide in deep tissue remains a challenge. Herein, we report a metal-free magnetic resonance imaging (MRI) and electron paramagnetic resonance (EPR) active contrast agent prepared by "click conjugating" paramagnetic organic radical contrast agents (ORCAs) to the surface of tobacco mosaic virus (TMV). While ORCAs are known to be reduced in vivo to an MRI/EPR silent state, their oxidation is facilitated specifically by reactive oxygen species-in particular, superoxide-and are largely unaffected by peroxides and molecular oxygen. Unfortunately, single molecule ORCAs typically offer weak MRI contrast. In contrast, our data confirm that the macromolecular ORCA-TMV conjugates show marked enhancement for T 1 contrast at low field (<3.0 T) and T 2 contrast at high field (9.4 T). Additionally, we demonstrated that the unique topology of TMV allows for a "quenchless fluorescent" bimodal probe for concurrent fluorescence and MRI/EPR imaging, which was made possible by exploiting the unique inner and outer surface of the TMV nanoparticle. Finally, we show TMV-ORCAs do not respond to normal cellular respiration, minimizing the likelihood for background, yet still respond to enzymatically produced superoxide in complicated biological fluids like serum.

Anti-Diabetic, Anti-Oxidant and Anti-Hyperlipidemic Activities of Flavonoids from Corn Silk on STZ-Induced Diabetic Mice.

Science.gov (United States)

Zhang, Yan; Wu, Liying; Ma, Zhongsu; Cheng, Jia; Liu, Jingbo

2015-12-23

Corn silk is a well-known ingredient frequently used in traditional Chinese herbal medicines. This study was designed to evaluate the anti-diabetic, anti-oxidant and anti-hyperlipidemic activities of crude flavonoids extracted from corn silk (CSFs) on streptozotocin (STZ)-induced diabetic mice. The results revealed that treatment with 300 mg/kg or 500 mg/kg of CSFs significantly reduced the body weight loss, water consumption, and especially the blood glucose (BG) concentration of diabetic mice, which indicated their potential anti-diabetic activities. Serum total superoxide dismutase (SOD) and malondialdehyde (MDA) assays were also performed to evaluate the anti-oxidant effects. Besides, several serum lipid values including total cholesterol (TC), triacylglycerol (TG), low density lipoprotein cholesterol (LDL-C) were reduced and the high density lipoprotein cholesterol level (HDL-C) was increased. The anti-diabetic, anti-oxidant and anti-hyperlipidemic effect of the CSFs suggest a potential therapeutic treatment for diabetic conditions.

Habitat of in vivo transformation influences the levels of free radical scavengers in Clinostomum complanatum: implications for free radical scavenger based vaccines against trematode infections.

Science.gov (United States)

Zafar, Atif; Rizvi, Asim; Ahmad, Irshad; Ahmad, Masood

2014-01-01

Since free radical scavengers of parasite origin like glutathione-S-transferase and superoxide dismutase are being explored as prospective vaccine targets, availability of these molecules within the parasite infecting different hosts as well as different sites of infection is of considerable importance. Using Clinostomum complanatum, as a model helminth parasite, we analysed the effects of habitat of in vivo transformation on free radical scavengers of this trematode parasite. Using three different animal models for in vivo transformation and markedly different sites of infection, progenetic metacercaria of C. complanatum were transformed to adult ovigerous worms. Whole worm homogenates were used to estimate the levels of lipid peroxidation, a marker of oxidative stress and free radical scavengers. Site of in vivo transformation was found to drastically affect the levels of free radical scavengers in this model trematode parasite. It was observed that oxygen availability at the site of infection probably influences levels of free radical scavengers in trematode parasites. This is the first report showing that habitat of in vivo transformation affects levels of free radical scavengers in trematode parasites. Since free radical scavengers are prospective vaccine targets and parasite infection at ectopic sites is common, we propose that infections at different sites, may respond differently to free radical scavenger based vaccines.

Developmental and environmental regulation of the Nicotiana plumbaginifolia cytosolic Cu/Zn-superoxide dismutase promoter in transgenic tobacco.

Science.gov (United States)

Hérouart, D; Van Montagu, M; Inzé, D

1994-03-01

Superoxide dismutases (SODs) play a key role in the cellular defense against reactive oxygen species. To study the transcriptional regulation at the cellular level, the promoter of the Nicotiana plumbaginifolia cytosolic gene encoding Cu/ZnSOD (SODCc) was fused to the beta-glucuronidase (GUS) reporter gene (gusA) and analyzed in transgenic tobacco plants. The promoter was highly active in vascular bundles of leaves and stems, where it is confined to phloem cells. In flowers, GUS activity was detected in ovules and pollen grains, in pigmented tissues of petals, and in vascular tissue of ovaries and anthers. In response to treatment with the superoxide-generating herbicide paraquat, very strong GUS staining was observed in photosynthetically active cells of leaves and in some epidermal root cells of seedlings. The expression of the SODCc-gusA was also induced in seedlings after heat shock and chilling and after treatment with sulfhydryl antioxidants such as reduced glutathione and cysteine. It is postulated that SODCc expression is directly linked to a cell-specific production of excess superoxide radicals in the cytosol.

Ethylene formation from methionine as a method to evaluate oxygen free radical scavenging and metal inactivation by cosmetics.

Science.gov (United States)

Galey, J B; Millecamps, F; Nguyen, Q L

1991-04-01

Synopsis It has been proposed that oxygen free radicals are involved in skin aging. This paper describes a new method for the evaluation of oxygen free radical scavenging by cosmetic products. It is based on the measurement, by gas chromatography, of ethylene produced during the oxidation of methionine by the hydroxyl radical. OH. is produced by an iron catalyzed superoxide-driven Fenton reaction in which superoxide is obtained by photochemical oxygen reduction. The cosmetic is applied, together with methionine, riboflavine, NADH, FeCl(3) and EDTA, on a glass microfibre filter and submitted to UVA exposure through a quartz cell. Ethylene is then measured from aliquots of the atmosphere inside the cell. Catalase or Desferal completely inhibits ethylene production. SOD or high concentrations of hydroxyl radical scavengers (Mannitol, DMSO etc.) afford a partial protection. Thus the efficiency of O(2) (-)., H(2)O(2) and OH. scavengers and iron chelators can be measured. The main advantage of this test is that it is performed in conditions which simulate skin during UV exposure (e.g. air and UV exposed thin layer). Furthermore, as it is non-invasive, it can also be applied to human skin in vivo.

Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag{sup +}/TiO{sub 2}: Influence of electron donating and withdrawing substituents

Energy Technology Data Exchange (ETDEWEB)

Xiao, Jiadong [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xie, Yongbing, E-mail: ybxie@ipe.ac.cn [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Han, Qingzhen [State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Cao, Hongbin [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Wang, Yujiao [Department of Chemical and Biomedical Engineering, University of Science and Technology Beijing (China); Nawaz, Faheem; Duan, Feng [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2016-03-05

Highlights: • A weak EWG benefited photocatalytic oxidation of phenols the most. • Phenolic compounds were dominantly oxidized by ·O{sub 2}{sup −}, rather than ·OH, {sup 1}O{sub 2} or h{sup +}. • ·O{sub 2}{sup −} preferred to nucleophilically attack EDG substituted phenols. • ·O{sub 2}{sup −} more likely electrophilically attacked EWG substituted phenols. • ·O{sub 2}{sup −} simultaneously nucleophilically and electrophilically assaulted p-chlorophenol. - Abstract: A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag{sup +}/TiO{sub 2} suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (·O{sub 2}{sup −}) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between ·O{sub 2}{sup −} and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of ·O{sub 2}{sup −} and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by ·O{sub 2}{sup −}, while ·O{sub 2}{sup −} preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by ·O{sub 2}{sup −} could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate

Delayed ultraviolet light-induced cessation of respiration by inadequate aeration of Escherichia coli

International Nuclear Information System (INIS)

Joshi, J.G.; Swenson, P.A.; Schenley, R.L.

1977-01-01

Inadequately aerated Escherichia coli B/r cultures did not shut their respiration off 60 min after ultraviolet light (52 J/m 2 at 254 nm) as they did when well supplied with oxygen. Since cessation of respiration is associated with cell death, the result suggested that oxygen toxicity by superoxide radicals generated by cell metabolism might be responsible for cell death. The specific activity of superoxide dismutase, which scavenges O 2 - radicals, increased twofold after 90 min of adequate aeration, but the specific activity of catalase remained constant. Respiration and viability of irradiated cells were affected not at all by the presence of superoxide dismutase and only slightly by the presence of catalase. Metal ions such as Mn 2+ and Fe 2+ , inducers of superoxide dismutase, had no effect on respiration and viability. When irradiated cells were incubated under N 2 for 90 min, the respiration, growth, and viability time-course responses were the same as for cells not exposed to anaerobiosis. We conclude that superoxide anions generated at the time of irradiation play no part in cessation of respiration and cell death and that inadequate aeration or anaerobiosis delays the ultraviolet light-induced synthesis of proteins responsible for the irreversible cessation of respiration

Real-time investigation of antibiotics-induced oxidative stress and superoxide release in bacteria using an electrochemical biosensor.

Science.gov (United States)

Liu, Xiaobo; Marrakchi, Mouna; Jahne, Michael; Rogers, Shane; Andreescu, Silvana

2016-02-01

The involvement of oxidative stress in the mechanism of antibiotics-meditated cell death is unclear and subject to debate. The kinetic profile and a quantitative relationship between the release of reactive oxygen species (ROS), bacteria and antibiotic type remain elusive. Here we report direct measurements and analytical quantification of the release of superoxide radicals (O2(·-)), a major contributor to ROS, in antibiotics-treated bacterial cultures using a cytochrome c electrochemical biosensor. The specificity of electrochemical measurements was established by the addition of superoxide dismutase (SOD) which decreased the O2(·-) signal. Measurements using a general ROS-specific fluorescence dye and colony forming units (CFU) assays were performed side-by-side to determine the total ROS and establish the relationship between ROS and the degree of lethality. Exposure of Escherichia coli and Listeria monocytogenes cultures to antibiotics increased the release of O2(·-) radicals in a dose-dependent manner, suggesting that the transmembrane generation of ROS may occur as part of the antibiotic action. The study provides a quantitative methodology and fundamental knowledge to further explore the role of oxidative stress in antibiotics-meditated bacterial death and to assess physiological changes associated with the complex metabolic events related to oxidative stress and bacterial resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

Radiolysis of ferrocyanide solutions studied by infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Le Caer, S. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France)]. E-mail: sophie.le-caer@cea.fr; Vigneron, G. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France); Renault, J.P. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France); Pommeret, S. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191Gif-sur-Yvette Cedex (France)

2007-08-15

The behavior of the neutral and basic aqueous ferrocyanide system under irradiation is investigated using the coupling of a LINAC with infrared spectroscopy. The comparison between the neutral and basic system evidences the formation of the hydroxopentacyanoferrate (III) ions and gives information on the reaction mechanisms. The pseudo-protective effect of the dissolved dioxygen on the ferrocyanide is explained via a mechanism implying the superoxide radical anion.

Anti-Diabetic, Anti-Oxidant and Anti-Hyperlipidemic Activities of Flavonoids from Corn Silk on STZ-Induced Diabetic Mice

Directory of Open Access Journals (Sweden)

Yan Zhang

2015-12-01

Full Text Available Corn silk is a well-known ingredient frequently used in traditional Chinese herbal medicines. This study was designed to evaluate the anti-diabetic, anti-oxidant and anti-hyperlipidemic activities of crude flavonoids extracted from corn silk (CSFs on streptozotocin (STZ-induced diabetic mice. The results revealed that treatment with 300 mg/kg or 500 mg/kg of CSFs significantly reduced the body weight loss, water consumption, and especially the blood glucose (BG concentration of diabetic mice, which indicated their potential anti-diabetic activities. Serum total superoxide dismutase (SOD and malondialdehyde (MDA assays were also performed to evaluate the anti-oxidant effects. Besides, several serum lipid values including total cholesterol (TC, triacylglycerol (TG, low density lipoprotein cholesterol (LDL-C were reduced and the high density lipoprotein cholesterol level (HDL-C was increased. The anti-diabetic, anti-oxidant and anti-hyperlipidemic effect of the CSFs suggest a potential therapeutic treatment for diabetic conditions.

Eosin Y photoredox catalyzed net redox neutral reaction for regiospecific annulation to 3-sulfonylindoles via anion oxidation of sodium sulfinate salts.

Science.gov (United States)

Rohokale, Rajendra S; Tambe, Shrikant D; Kshirsagar, Umesh A

2018-01-24

An eosin Y photoredox catalyzed net redox neutral process for 3-sulfonylindoles via the anionic oxidation of sodium sulfinate salts and its radical cascade cyclization with 2-alkynyl-azidoarenes was developed with visible light as a mediator. The reaction offers metal and oxidant/reductant free, visible light mediated vicinal sulfonamination of alkynes to 2-aryl/alkyl-3-sulfonylindoles and proceeds via the generation of a sulfur-centered radical through direct oxidation of the sulfinate anion by an excited photocatalyst with a reductive quenching cycle. The mild conditions, use of an organic dye as photo-catalyst, bench stability and easily accessible starting materials make the present approach green and attractive.

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.

Prolonged exposure of resveratrol induces reactive superoxide species-independent apoptosis in murine prostate cells.

Science.gov (United States)

Kumar, Sanjay; Stokes, James; Singh, Udai P; Scissum-Gunn, Karyn; Singh, Rajesh; Manne, Upender; Mishra, Manoj K

2017-10-01

Nitric oxide, a signaling molecule, inhibits mitochondrial respiration by binding with cytochrome c oxidase, resulting in elevated production of reactive superoxide species (reactive oxygen and nitrogen) in the mitochondria and increased susceptibility to cell death. Generation of mitochondrial superoxide species can be suppressed by natural compounds such as resveratrol, a dietary polyphenol found in the skin of red fruits. In various cancer cells, resveratrol shows anti-oxidant and cancer preventive properties. Since, the effect of resveratrol on reactive superoxide species-independent apoptosis in prostate cancer cells is not well illustrated; therefore, we investigated this phenomenon in TRAMP murine prostate cancer cells. To accomplish this, TRAMP cells were incubated with resveratrol, resveratrol + DETA-NONOate, DETA-NONOate (nitric oxide donor), resveratrol + L-NMMA, or L-NMMA (nitric oxide inhibitor) for 48 h, and reactive superoxide species in the mitochondria and culture supernatant were measured. In addition, the mitochondrial membrane potential, cell viability, expression of apoptotic markers (Bax and Bcl2), γ-H2A.x, p53, and caspase-3 was determined. We found that resveratrol suppressed reactive superoxide species such as reactive oxygen species in the mitochondria and nitric oxide in culture supernatant when compared to the DETA-NONOate treatment and disrupted the mitochondrial membrane potential. Resveratrol also reduced cell viability, altered the expression of apoptotic markers (Bax and Bcl2), and increased expression of γ-H2A.x (indicative marker of DNA fragmentation) and p53 (a critical DNA damage response protein). However, there was no appreciable modulation of the caspase-3. Therefore, our data suggest that resveratrol induces superoxide species-independent apoptosis and may act as a therapeutic agent against prostate cancer.

Anti-inflammatory properties of clovamide and Theobroma cacao phenolic extracts in human monocytes: evaluation of respiratory burst, cytokine release, NF-κB activation, and PPARγ modulation.

Science.gov (United States)

Zeng, Huawu; Locatelli, Monica; Bardelli, Claudio; Amoruso, Angela; Coisson, Jean Daniel; Travaglia, Fabiano; Arlorio, Marco; Brunelleschi, Sandra

2011-05-25

There is a great interest in the potential health benefits of biologically active phenolic compounds in cocoa (Theobroma cacao) and dark chocolate. We investigated the anti-inflammatory potential of clovamide (a N-phenylpropenoyl-L-amino acid amide present in cocoa beans) and two phenolic extracts from unroasted and roasted cocoa beans, by evaluating superoxide anion (O(2)(-)) production, cytokine release, and NF-κB activation in human monocytes stimulated by phorbol 12-myristate 13-acetate (PMA). The effects of rosmarinic acid are shown for comparison. Clovamide and rosmarinic acid inhibited PMA-induced O(2)(-) production and cytokine release (with a bell-shaped curve and maximal inhibition at 10-100 nM), as well as PMA-induced NF-κB activation; the two cocoa extracts were less effective. In all tests, clovamide was the most potent compound and also enhanced peroxisome proliferator-activated receptor-γ (PPARγ) activity, which may exert anti-inflammatory effects. These findings indicate clovamide as a possible bioactive compound with anti-inflammatory activity in human cells.

Radical inactivation of a biological sulphydryl molecule

International Nuclear Information System (INIS)

Lin, W.S.; Lal, M.; Gaucher, G.M.; Armstrong, D.A.

1977-01-01

Reactive species produced from the free radical-induced chain oxidation of low molecular weight sulphydryl-containing molecules in aerated solutions deactivate the sulphydryl-containing enzyme papain, forming both reparable mixed disulphides and non-reparable products. This inactivation is highly efficient for penicillamine and glutathione, but almost negligible with cysteine, which is a protector of papain for [cysteine] / [papain] >= 5 under all conditions used. In the case of glutathione, superoxide dismutase caused only a small reduction in the inactivation and peroxide yields were small, implying that the deactivating species are not .O 2 - but RSOO. radicals or products from them. For penicillamine, however, dimutase was highly effective and the peroxide yields were relatively large, demonstrating that .O 2 - or a radical with similar capabilities for forming H 2 O 2 and being deactivated by dismutase was involved. Although in the presence of dismutase penicillamine is a better protector of non-reparable papain inactivation than glutathione, it suffers from a deficiency in that the papain-penicillamine mixed disulphide, which is always formed, cannot be repaired by spontaneous reaction with RSH molecules. (author)

In vitro free radical scavenging activity of ethanolic extract of the whole plant of Evolvulus alsinoides (L.) L.

Science.gov (United States)

Gomathi, Duraisamy; Ravikumar, Ganesan; Kalaiselvi, Manokaran; Vidya, Balasubramaniam; Uma, Chandrasekar

2015-06-01

To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction, superoxide radical scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard. The extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner. Evolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.

Deciphering free-radical code of radiation effects

International Nuclear Information System (INIS)

Volovyk, S.; Bazyka, D.; Loganovsky, K.; Bebeshko, V.

2007-01-01

Complete text of publication follows. Objective: Ionizing radiation is fundamental environmental factor for life origin and evolution. Free radicals, primordial 'sea' for life conceiving and existence, induced by cosmic and terrestrial background radiation, are evolutionally archetypal, ubiquitous, and omnipotent in physiological- pathophysiological dichotomy. Classical free-radical paradigm in radiation biology and medicine, focused in essence on oxidative damage, needs new conceptualization and generalization. Methods: Suggested novel insights into free radicals dual immanent nature and functions in organism systems are based on original concepts of radicals dynamic charge transfer (CT) - redox ambivalence (interactional nucleo-, electro-, and ambiphilicity spectrum); pertinent chemical reactivity and selectivity delocalization model; physiological functional ambivalence and complementarity, and dynamic free-radical homeostasis. Results: Subtle perturbations in radicals CT spatiotemporal homeodynamics, in responsive signaling / controlling networks, concomitant alterations in genes expression, transcription, and apoptosis, redox control of mitochondrial ET chain, telomere/telomerase balance, DNA CT, circadian clock, hemispheric biochemical dominance/accentuation, including alteration of nitric oxide-superoxide complementarity, membranes permeability, neurotransmission pattern, synaptic circuitry, etc under radiation exposure have more fundamental impact on organism systems (especially CNS and CVS) deterioration than simple radicals inflicted oxidative (nitrosative) damage of cellular constituents. Conclusions: This novel conceptualization of free-radical paradigm constitutes new dimension in deciphering molecular mechanisms of radiation effects on subtle borderline norm-pathology and continuity-discontinuity dichotomy in organisms systems disorders - CT(redox)omics, which involves investigation of CT, redox, and spin states of free radicals, DNA bases

Matrix isolation spectroscopic studies of the radical ions of 2,5-diphenyloxazole (Preprint No. RC-15)

International Nuclear Information System (INIS)

Wani, A.M.

1988-02-01

The radical ions of 2,5-diphenyloxazole (PPO) produced upon γ-irradiation were studied at 77 K in organic glasses by optical absorption spectroscopy. The dependence of absorption spectra on the nature of the matrix, electron and hole scavengers is interpretted and the absorption bands are assigned to the anionic and cationic radical species of PPO. (author). 6 refs

Radical scavenging activities of Rio Red grapefruits and Sour orange fruit extracts in different in vitro model systems.

Science.gov (United States)

Jayaprakasha, G K; Girennavar, Basavaraj; Patil, Bhimanagouda S

2008-07-01

Antioxidant fractions from two different citrus species such as Rio Red (Citrus paradise Macf.) and Sour orange (Citrus aurantium L.) were extracted with five different polar solvents using Soxhlet type extractor. The total phenolic content of the extracts was determined by Folin-Ciocalteu method. Ethyl acetate extract of Rio Red and Sour orange was found to contain maximum phenolics. The dried fractions were screened for their antioxidant activity potential using in vitro model systems such as 1,1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method and nitroblue tetrazolium (NBT) reduction at different concentrations. The methanol:water (80:20) fraction of Rio Red showed the highest radical scavenging activity 42.5%, 77.8% and 92.1% at 250, 500 and 1000 ppm, respectively, while methanol:water (80:20) fraction of Sour orange showed the lowest radical scavenging activity at all the tested concentrations. All citrus fractions showed good antioxidant capacity by the formation of phosphomolybdenum complex at 200 ppm. In addition, superoxide radical scavenging activity was assayed using non-enzymatic (NADH/phenaxine methosulfate) superoxide generating system. All the extracts showed variable superoxide radical scavenging activity. Moreover, methanol:water (80:20) extract of Rio Red and methanol extract of Sour orange exhibited marked reducing power in potassium ferricyanide reduction method. The data obtained using above in vitro models clearly establish the antioxidant potential of citrus fruit extracts. However, comprehensive studies need to be conducted to ascertain the in vivo bioavailability, safety and efficacy of such extracts in experimental animals. To the best of our knowledge, this is the first report on antioxidant activity of different polar extracts from Rio Red and Sour oranges.

METRONIDAZOLE RADICAL ANION FORMATION STUDIED BY MEANS OF ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

Czech Academy of Sciences Publication Activity Database

Gál, Miroslav; Sokolová, Romana; Kolivoška, Viliam; Morovská Turoňová, A.; Ambrová, M.; Híveš, J.

2011-01-01

Roč. 76, č. 12 (2011), s. 1607-1617 ISSN 0010-0765 R&D Projects: GA ČR GP203/09/P502; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : radicals * radiopharmaceuticals * electron transfer Subject RIV: CG - Electrochemistry Impact factor: 1.283, year: 2011

Participation of superoxide generating system, superoxide dismutase and vitamin E in the radiation hazards

International Nuclear Information System (INIS)

Aono, Kaname; Yamamoto, Michio; Iida, Sosuke; Utsumi, Kozo

1978-01-01

In relation to the mechanism by which hemolysis was induced in radiated human erythrocytes in vitro, several inducements of membrane lipid peroxidation and protective effects of vitamin E (V.E) and superoxide dismutase (SOD) were investigated. (1) K + -release from erythrocytes was accelerated by radiation prior to hemolysis. These accelerated hemolysis and K + -release were protected remarkably by V.E and evidently by SOD. (2) Mitochondrial Fe 2+ induced and Fe 3+ -superoxide generating system -- ADP induced lipid peroxidation, and microsomal superoxide generating system -- induced lipid peroxidation were also protected by V.E and SOD. (3) Radiation of x-ray or 60 Co γ-ray accelerated lipid peroxidation of liver homogenate, microsome and liposome. Some of these accelerated lipid peroxidations were protected effectively by V.E and SOD. These results suggest that superoxide and/or OH generation by radiation induces of membrane lipid peroxidation, which leads deterioration of membrane resulting in the change of ion permeability and then hemolysis. (author)

The role of metals in production and scavenging of reactive oxygen species in photosystem II.

Science.gov (United States)

Pospíšil, Pavel

2014-07-01

Metal ions play a crucial role in enzymatic reactions in all photosynthetic organisms such as cyanobacteria, algae and plants. It well known that metal ions maintain the binding of substrate in the active site of the metalloenzymes and control the redox activity of the metalloenzyme in the enzymatic reaction. A large pigment-protein complex, PSII, known to serve as a water-plastoquinone oxidoreductase, contains three metal centers comprising non-heme iron, heme iron of Cyt b559 and the water-splitting manganese complex. Metal ions bound to PSII proteins maintain the electron transport from water to plastoquinone and regulate the pro-oxidant and antioxidant activity in PSII. In this review, attention is focused on the role of PSII metal centers in (i) the formation of superoxide anion and hydroxyl radicals by sequential one-electron reduction of molecular oxygen and the formation of hydrogen peroxide by incomplete two-electron oxidation of water; and (ii) the elimination of superoxide anion radical by one-electron oxidation and reduction (superoxide dismutase activity) and of hydrogen peroxide by two-electron oxidation and reduction (catalase activity). The balance between the formation and elimination of reactive oxygen species by PSII metal centers is discussed as an important aspect in the prevention of photo-oxidative damage of PSII proteins and lipids. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Albert Einstein: Radical Pacifist and Democrat

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Jayaraman, T.

We draw attention here to the radical political grounding of Einstein's pacifism. We also drescribe some less commonly known aspects of his commitment to civil liberties, particularly in the context of the anti-l hysteria and anti-racism current in the United States of the late 1940s and 1950s. We also examine briefly his views on socialism.

Isolation and characterization of flavanols from Anthocephalus cadamba and evaluation of their antioxidant, antigenotoxic, cytotoxic and COX-2 inhibitory activities

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Madhu Chandel

Full Text Available ABSTRACT In search of lead molecules for use in disease prevention and as food additive from natural sources, two flavanols were isolated from leaves of Anthocephalus cadamba (Roxb. Miq., Rubiaceae. Their structures were established as 6-hydroxycoumarin-(4"→8-(--epicatechin and 6-hydroxycoumarin-(4"→8-(--epicatechin-(4→6‴-(--epicatechin on the basis of spectroscopic data. Both the compounds exhibited potent antioxidant and antigenotoxic activity. 6-Hydroxycoumarin-(4"→8-(--epicatechin scavenged DPPH, ABTS+.and superoxide anion radicals with IC50 values of 6.09 µg/ml, 5.95 µg/ml and 42.70 µg/ml respectively whereas the IC50 values for 6-hydroxycoumarin-(4"→8-(--epicatechin-(4→6‴-(--epicatechin were 6.62 µg/ml for DPPH free radicals, 6.93 µg/ml for ABTS radical cations and 49.08 µg/ml for superoxide anion radicals. Both the compounds also exhibited potent reducing potential in reducing power assay and protected the plasmid DNA (pBR322 against the attack of hydroxyl radicals generated by Fenton's reagent in DNA protection assay. In SOS chromotest, 6-hydroxycoumarin-(4"→8-(--epicatechin decreased the induction factor induced by 4NQO (20 µg/ml and aflatoxin B1 (20 µg/ml by 31.78% and 65.04% respectively at a concentration of 1000 µg/ml. On the other hand, 6-hydroxycoumarin-(4"→8-(--epicatechin-(4→6‴-(--epicatechin decreased the genotoxicity of these mutagens by 37.11% and 47.05% respectively. It also showed cytotoxicity in COLO-205 cancer cell line with GI50 of 435.71 µg/ml. Both the compounds showed moderate cyclooxygenase-2 inhibitory activity.

Antioxidant, lipid peroxidation inhibition and free radical scavenging efficacy of a diterpenoid compound sugiol isolated from Metasequoia glyptostroboides.

Science.gov (United States)

Bajpai, Vivek K; Sharma, Ajay; Kang, Sun Chul; Baek, Kwang-Hyun

2014-01-01

To investigate the antioxidant efficacy of a biologically active diterpenoid compound sugiol isolated from Metasequoia glyptostroboides (M. glyptostroboides) in various antioxidant models. An abietane type diterpenoid sugiol, isolated from ethyl acetate extract of M. glyptostroboides cones, was analyzed for its antioxidant efficacy as reducing power ability and lipid peroxidation inhibition as well as its ability to scavenge free radicals such as 1,1-diphenyl-2-picryl hydrazyl, nitric oxide, superoxide and hydroxyl radicals. The sugiol showed significant and concentration-dependent antioxidant and free radical scavenging activities. Consequently, the sugiol exerted lipid peroxidation inhibitory effect by 76.5% as compared to α-tocopherol (80.13%) and butylated hydroxyanisole (76.59%). In addition, the sugiol had significant scavenging activities of 1,1-diphenyl-2-picryl hydrazyl, nitric oxide, superoxide and hydroxyl free radicals in a concentration-dependent manner by 78.83%, 72.42%, 72.99% and 85.04%, when compared to the standard compound ascorbic acid (81.69%, 74.62%, 73.00% and 73.79%) and α-tocopherol/butylated hydroxyanisole (84.09%, 78.61%, 74.45% and 70.02%), respectively. These findings justify the biological and traditional uses of M. glyptostroboides or its secondary metabolites as confirmed by its promising antioxidant efficacy. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Doxorubicin hepatotoxicity and hepatic free radical metabolism in rats

International Nuclear Information System (INIS)

Kalender, Yusuf; Yel, Mustafa; Kalender, Suna

2005-01-01

Doxorubicin (DXR) is an anthracycline antibiotic, broady used in tumor therapy. In the present study we investigated whether vitamin E and catechin can reduce the toxic effects of doxorubicin. Vitamin E (200 IU/kg/week), catechin (200 mg/kg/week), doxorubicin (5 mg/kg/week), doxorubicin + vitamin E (200 IU/kg/week), doxorubicin + catechin (200 mg/kg/week) combinations were given to rats weighing 210-230 g (n = 6/group). Changes in major enzymes participating in free radical metabolism superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase (GSHPx), catalase (CAT) and malondialdehyde (MDA) were evaluated in the livers of all animals. Superoxide dismutase and catalase activity increased in the doxorubicin-treated group compared to control (P 0.05). Electron microscopic studies supported biochemical findings. We conclude that vitamin E and catechin significantly reduce doxorubicin-induced hepatotoxicity in rats

Oxygen toxicity

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C. A. van der Westhuizen

1990-07-01

Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

Novel Fluorometric Method for the Determination of Production Rate and Steady-State Concentration of Photochemically Generated Superoxide Radical in Seawater Using 3',6'-(Diphenylphosphinyl)fluorescein.

Science.gov (United States)

Anifowose, Adebanjo Jacob; Takeda, Kazuhiko; Sakugawa, Hiroshi

2015-12-15

Superoxide radical (O2(•-)) is an important reactive oxygen species in seawater. Measurements of its production rates and steady-state concentrations generated by photochemical processes have been a Herculean task over the years. In this study, a probe - 3'6'-(diphenylphosphinyl)fluorescein (PF-1) - was used to trap photochemically generated O2(•-) in seawater, thereby yielding fluorescein. The fluorescein produced was measured by an isocratic fluorescence HPLC at excitation/emission wavelengths of 490/513 nm, respectively. The reaction rate constant of PF-1 with O2(•-) (kPF-1) was pH-dependent: (3.2-23.5) × 10(7) M(-1) s(-1) at pHTOT 7.65-8.50. By applying appropriate equations, both the production rate and the steady-state concentration of O2(•-) generated by photochemical reactions in the seawater were quantified. Under the optimized experimental conditions, fluorescein standards (3-50 nM) exhibited linearity in the seawater by HPLC. The photoformation of fluorescein, due to the reaction of PF-1 with the O2(•-) photochemically produced in the seawater, was linear within the 20 min irradiation. The detection limit of the fluorescein photoformation rate was 0.03 pM s(-1), defined as 3σ of the lowest standard fluorescein concentration per 20 min irradiation. Using this value, the yield of fluorescein, and the fraction of O2(•-) that reacted with PF-1 in the seawater, the detection limit of the O2(•-) photoformation rate was 1.78 pM s(-1). Superoxide measurements using the proposed method were relatively unaffected by the potential interfering species in seawater. Application of the proposed method to ten (10) seawater samples from the Seto Inland Sea, Japan, resulted in measured O2(•-) photoformation rates of 3.1-8.5 nM s(-1), with steady-state concentrations ranging (0.06-0.3) × 10(-10) M. The method is simple, requires no technical sample preparation, and can be used to analyze a large number of samples.

The cytoplasmic Cu,Zn superoxide dismutase of saccharomyces cerevisiae is required for resistance to freeze-thaw stress. Generation of free radicals during freezing and thawing

DEFF Research Database (Denmark)

Park, J I; Grant, C M; Davies, Michael Jonathan

1998-01-01

The involvement of oxidative stress in freeze-thaw injury to yeast cells was analyzed using mutants defective in a range of antioxidant functions, including Cu,Zn superoxide dismutase (encoded by SOD1), Mn superoxide dismutase (SOD2), catalase A, catalase T, glutathione reductase, gamma...

Radical scavenging potentials of single and combinatorial herbal formulations in vitro

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Okey A. Ojiako

2016-04-01

Full Text Available Reactive oxygen and nitrogen species (RONS are involved in deleterious/beneficial biological processes. The present study sought to investigate the capacity of single and combinatorial herbal formulations of Acanthus montanus, Emilia coccinea, Hibiscus rosasinensis, and Asystasia gangetica to act as superoxide radicals (SOR, hydrogen peroxide (HP, nitric oxide radical (NOR, hydroxyl radical (HR, and 2,2-diphenyl-1-picrylhydrazyl (DPPH radical antagonists using in vitro models. The herbal extracts were single herbal formulations (SHfs, double herbal formulations (DHfs, triple herbal formulations (THfs, and a quadruple herbal formulation (QHf. The phytochemical composition and radical scavenging capacity index (SCI of the herbal formulations were measured using standard methods. The flavonoids were the most abundant phytochemicals present in the herbal extracts. The SCI50 defined the concentration (μg/mL of herbal formulation required to scavenge 50% of the investigated radicals. The SHfs, DHfs, THfs, and QHf SCI50 against the radicals followed the order HR > SOR > DPPH radical > HP > NOR. Although the various herbal formulations exhibited ambivalent antioxidant activities in terms of their radical scavenging capabilities, a broad survey of the results of the present study showed that combinatorial herbal formulations (DHfs, THfs, and QHf appeared to exhibit lower radical scavenging capacities than those of the SHfs in vitro.

Biological Superoxide In Manganese Oxide Formation

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Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

2011-12-01

Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke

International Nuclear Information System (INIS)

Lee, C.K.; Brown, B.G.; Rice, W.Y. Jr.; Doolittle, D.J.

1989-01-01

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals

Skin anti-photoaging properties of ginsenoside Rh2 epimers in UV ...

Indian Academy of Sciences (India)

2014-07-16

Jul 16, 2014 ... eration of superoxide radical in keratinocytes, which is sub- sequently .... at 37°C, the cells were twice washed with 1 mL FBS-free medium. Then ..... Indian plant widely used for inflammatory diseases, is able to diminish the ...