How to characterize an antioxidant: an update

1995 ◽  
Vol 61 ◽  
pp. 73-101 ◽  
Author(s):  
Barry Halliwell
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Hydroxyl Radical ◽  
Hypochlorous Acid ◽  
Water Soluble ◽  
Peroxyl Radicals ◽  
Low Concentrations ◽  
Ferryl Species ◽  
Do So

The term antioxidant is widely used but rarely defined. One suggested definition is that an antioxidant is 'a substance that, when present at low concentrations compared with those of an oxidizable substrate, significantly delays or prevents oxidation of that substrate'. Many substances have been suggested to act as antioxidants in vivo, but few have been proved to do so. This chapter addresses the criteria necessary to evaluate a proposed antioxidant activity. Simple methods for assessing the possibility of physiologically feasible scavenging of important biological oxygen-derived species (superoxide, hydrogen peroxide, hydroxyl radical, hypochlorous acid, haem-associated ferryl species, radicals derived from activated phagocytes and peroxyl radicals, both lipid-soluble and water-soluble) are presented. Methods that may be used to gain evidence that a compound actually does function as an antioxidant in vivo are discussed.

Formation of Hydroxyl Radicals from Hydrogen Peroxide and Iron Salts by Superoxide- and Ascorbate-Dependent Mechanisms: Relevance to the Pathology of Rheumatoid Disease

1983 ◽  
Vol 64 (6) ◽  
pp. 649-653 ◽  
Author(s):  
D. A. Rowley ◽  
B. Halliwell
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Oxygen Radicals ◽  
Rheumatoid Disease ◽  
Iron Salts ◽  
Low Concentrations ◽  
Short Period ◽  
Generating System

1. Superoxide and hydrogen peroxide are formed by activated phagocytes and react together in the presence of iron salts to form the hydroxyl radical, which attacks hyaluronic acid. Ascorbic acid also interacts with hydrogen peroxide and iron salts to form hydroxyl radical in a reaction independent of superoxide. Since iron salts, ascorbate and activated phagocytes are present in the rheumatoid joint, experiments were designed to see whether ascorbate-dependent or superoxide-dependent formation of hydroxyl radicals would be more important in vivo. 2. in the present study, addition of ascorbate to a superoxide-generating system at concentrations of 100 μmol/l provoked a superoxide-independent formation of hydroxyl radicals for a short period. Lower concentrations of ascorbate did not do this. It is therefore suggested that the superoxide-dependent reaction is probably more important. 3. It is further suggested that destruction of ascorbate by oxygen radicals formed by activated phagocytes accounts for the previously reported low concentrations of this compound in the serum and synovial fluid of rheumatoid patients.

Evaluation of antioxidant activity of Melothria maderaspatana in vitro

2010 ◽  
Vol 5 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Boobalan Raja ◽  
Kodukkur Pugalendi
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Free Radical ◽  
Hydroxyl Radical ◽  
Superoxide Anion ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Free Radical Scavenging ◽  
Melothria Maderaspatana

AbstractIn this study, an aqueous extract of leaves from Melothria maderaspatana was tested for in vitro antioxidant activity. Free radical scavenging assays, such as hydroxyl radical, hydrogen peroxide, superoxide anion radical and 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2’-azinobis-(3-ethyl-enzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power assay, were studied. The extract effectively scavenged hydroxyl radical, hydrogen peroxide and superoxide anion radicals. It also scavenged DPPH and ABTS radicals. Furthermore, it was found to have reducing power. All concentrations of leaf extract exhibited free radical scavenging and antioxidant power, and the preventive effects were in a dose-dependent manner. The antioxidant activities of the above were compared to standard antioxidants such as butylated hydroxytoluene (BHT), ascorbic acid, and α-tocopherol. The results obtained in the present study indicate that the M. maderaspatana extract could be considered a potential source of natural antioxidant.

scholarly journals In Vitro and In Vivo Antioxidant Activity of a Water-Soluble Polysaccharide from Dendrobium denneanum

Molecules ◽  
2011 ◽  
Vol 16 (2) ◽  
pp. 1579-1592 ◽  
Author(s):  
Aoxue Luo ◽  
Zhongfu Ge ◽  
Yijun Fan ◽  
Aoshuang Luo ◽  
Ze Chun ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Water Soluble ◽  
Soluble Polysaccharide

scholarly journals Antioxidant Activity of Hypericum androsaemum Infusion: Scavenging Activity against Superoxide Radical, Hydroxyl Radical and Hypochlorous Acid

2002 ◽  
Vol 25 (10) ◽  
pp. 1320-1323 ◽  
Author(s):  
Patrícia Valentão ◽  
Eduarda Fernandes ◽  
Félix Carvalho ◽  
Paula Branquinho Andrade ◽  
Rosa Maria Seabra ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Hydroxyl Radical ◽  
Superoxide Radical ◽  
Hypochlorous Acid ◽  
Scavenging Activity

scholarly journals Amaranth Leaf Extract Protects Against Hydrogen Peroxide Induced Oxidative Stress in Drosophila Melanogaster

2021 ◽  
Author(s):  
Johnmark Ndinawe ◽  
Hellen W. Kinyi
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Drosophila Melanogaster ◽  
Leaf Extract ◽  
Dependent Manner ◽  
Polyphenol Compounds ◽  
Dose Dependent

Abstract ObjectiveAmaranths leaves are rich in ascorbic acid and polyphenol compounds which have antioxidant activity. The aim of this study was to evaluate their in vivo antioxidant activity. The effect of consumption of Amaranth leaf extract on in vivo antioxidant activity, catalase enzyme activity and H2O2 induced oxidative stress in Drosophila melanogaster flies was assessed.ResultsConsumption of Amaranth leaf extract was associated with increased survival on exposure to H202 in a dose dependent manner in Drosophila melanogaster flies.

Beta-2-Agonists Have Antioxidant Function in vitro. 1. Inhibition of Superoxide Anion, Hydrogen Peroxide, Hypochlorous Acid and Hydroxyl Radical

Respiration ◽  
1997 ◽  
Vol 64 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Adrian Gillissen ◽  
Malgorzata Jaworska ◽  
Birgit Schärling ◽  
Dominique van Zwoll ◽  
Gerhard Schultze-Werninghaus
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Superoxide Anion ◽  
Hypochlorous Acid ◽  
Antioxidant Function ◽  
Beta 2

scholarly journals Yields of hydrogen peroxide from the reaction of hydroxyl radical with organic compounds in solution and ice

2011 ◽  
Vol 11 (14) ◽  
pp. 7209-7222 ◽  
Author(s):  
T. Hullar ◽  
C. Anastasio
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Organic Compounds ◽  
Octanoic Acid ◽  
Formation Rate ◽  
Peroxyl Radicals ◽  
Water Control ◽  
Organic Species ◽  
Simulated Solar Light ◽  
Octanedioic Acid

Abstract. Hydrogen peroxide (HOOH) is a significant oxidant in atmospheric condensed phases (e.g., cloud and fog drops, aqueous particles, and snow) that also photolyzes to form hydroxyl radical (•OH). •OH can react with organics in aqueous phases to form organic peroxyl radicals and ultimately reform HOOH, but the efficiency of this process in atmospheric aqueous phases, as well as snow and ice, is not well understood. We investigate HOOH formation from •OH attack on 10 environmentally relevant organic compounds: formaldehyde, formate, glycine, phenylalanine, benzoic acid, octanol, octanal, octanoic acid, octanedioic acid, and 2-butoxyethanol. Liquid and ice samples with and without nitrate (as an •OH source) were illuminated using simulated solar light, and HOOH formation rates were measured as a function of pH and temperature. For most compounds, the formation rate of HOOH without nitrate was the same as the background formation rate in blank water (i.e., illumination of the organic species does not produce HOOH directly), while formation rates with nitrate were greater than the water control (i.e., reaction of •OH with the organic species forms HOOH). Yields of HOOH, defined as the rate of HOOH production divided by the rate of •OH production, ranged from essentially zero (glycine) to 0.24 (octanal), with an average of 0.12 ± 0.05 (95 % CI). HOOH production rates and yields were higher at lower pH values. There was no temperature dependence of the HOOH yield for formaldehyde or octanedioic acid between −5 to 20 °C and ice samples had approximately the same HOOH yield as the aqueous solutions. In contrast, HOOH yields in formate solutions were higher at 5 and 10 °C compared to −5 and 20 °C. Yields of HOOH in ice for solutions containing nitrate and either phenylalanine, benzoate, octanal, or octanoic acid were indistinguishable from zero. Our HOOH yields were approximately half those found in previous studies conducted using γ-radiolysis, but this difference might be due to the much lower (and more environmentally relevant) •OH formation rates in our experiments.

scholarly journals The antioxidant action of taurine, hypotaurine and their metabolic precursors

1988 ◽  
Vol 256 (1) ◽  
pp. 251-255 ◽  
Author(s):  
O I Aruoma ◽  
B Halliwell ◽  
B M Hoey ◽  
J Butler
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Radical ◽  
Hypochlorous Acid ◽  
Cysteic Acid ◽  
Iron Ions ◽  
Antioxidant Action ◽  
Iron Ion ◽  
Metabolic Precursors ◽  
Sufficient Concentration

It has been suggested that taurine, hypotaurine and their metabolic precursors (cysteic acid, cysteamine and cysteinesulphinic acid) might act as antioxidants in vivo. The rates of their reactions with the biologically important oxidants hydroxyl radical (.OH), superoxide radical (O2.-), hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) were studied. Their ability to inhibit iron-ion-dependent formation of .OH from H2O2 by chelating iron ions was also tested. Taurine does not react rapidly with O2.-, H2O2 or .OH, and the product of its reaction with HOCl is still sufficiently oxidizing to inactivate alpha 1-antiproteinase. Thus it seems unlikely that taurine functions as an antioxidant in vivo. Cysteic acid is also poorly reactive to the above oxidizing species. By contrast, hypotaurine is an excellent scavenger of .OH and HOCl and can interfere with iron-ion-dependent formation of .OH, although no reaction with O2.- or H2O2 could be detected within the limits of our assay techniques. Cysteamine is an excellent scavenger of .OH and HOCl; it also reacts with H2O2, but no reaction with O2.- could be measured within the limits of our assay techniques. It is concluded that cysteamine and hypotaurine are far more likely to act as antioxidants in vivo than is taurine, provided that they are present in sufficient concentration at sites of oxidant generation.

Trolox and ascorbate: are they synergistic in protecting liver cells in vitro and in vivo?

1991 ◽  
Vol 69 (2-3) ◽  
pp. 198-201 ◽  
Author(s):  
L.-H. Zeng ◽  
Jun Wu ◽  
Doug Carey ◽  
T.-W. Wu
Keyword(s):  
Hydrogen Peroxide ◽  
Body Weight ◽  
Ischemia Reperfusion ◽  
Water Soluble ◽  
Cultured Hepatocytes ◽  
Hepatic Ischemia ◽  
Multilamellar Liposomes ◽  
Hepatic Ischemia Reperfusion

From in vitro studies involving multilamellar liposomes or other artificial systems, several groups of workers have deduced that Trolox (a water-soluble analogue of vitamin E) and ascorbate are synergistic antioxidants. Here, we demonstrate that while Trolox and ascorbate individually protect cultured hepatocytes against oxyradicals generated either with xanthine oxidase plus hypoxanthine or with hydrogen peroxide, the two antioxidants do not appear to be synergistic when used in equimolar combinations. Also, in a rat model of hepatic ischemia–reperfusion, we observed that infusion of Trolox or ascorbate (7.5–10 μmol/kg body weight) into the postischemic liver reduced the reperfusion injury by 76 or 67%, respectively. However, when both compounds were used together (each at the same dose as used separately), the organ salvage amounted to only 79%. Therefore, there is no evidence of synergism between Trolox and ascorbate in our in vitro and especially in vivo systems.Key words: synergism, vitamin C, Trolox, antioxidants.

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