Radical intermediates and antioxidant activity of ascorbic acid

Liu, You‐Cheng; Liu, Zheng‐Li; Han, Zhen

doi:10.1007/bf03155996

Cited by 36 publications

(10 citation statements)

References 97 publications

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“…α-tocopherol (TOH), the most abundant and active form of vitamin E, is well known and the principal lipid-soluble chain-breaking antioxidant in plasma and erythrocytes (Burton and Ingold, 1986). Its synergistic antioxidative effect with other antioxidants, such as L-ascorbic acid (vitamin C), (Liu et al, 1988) green tea polyphenols (Zhou et al, 2005b) and resveratrol and its analogues, (Fang et al, 2002) has been well documented. Therefore, it is interesting to see if TOH can also interact synergistically with curcumin and its analogues.…”

Section: Resultsmentioning

confidence: 99%

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Dai

Chen

Zhou

et al. 2009

Phytotherapy Research

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Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, 1) is a yellow ingredient isolated from turmeric (curcumin longa). Many health benefits have been claimed for curcumin, and these have generally been ascribed to its radical-trapping antioxidant properties. In order to find more active antioxidants with 1 as the lead compound, we synthesized curcumin analogues, i.e., 1,7-bis(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione (2), 1-(3,4-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (3), 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (4), 1,7-bis (4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (5), 1,7-bis(3,4-dimethoxyphenyl)-1,6-heptadiene-3,5-dione (6), 1,7-bis(4-methoxyphenyl)-1,6-heptadiene-3,5-dione (7), and 1,7-diphenyl-1,6-heptadiene-3,5-dione (8). Antioxidative effects of curcumin and these analogues against the peroxidation of linoleic acid were studied in sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) micelles. The peroxidation was initiated thermally by a water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), and reaction kinetics were monitored by the formation of linoleic acid hydroperoxides. Kinetic analysis of the antioxidation process demonstrates that these compounds, except 6, 7 and 8, are effective antioxidants in micelles by H-atom abstraction from the phenolic groups. Compounds 2 and 3, which bear ortho-diphenoxyl functionality, possess significantly higher antioxidant activity than curcumin and other analogues, and the 4-hydroxy-3-methoxyphenyl group also plays an important role in the antioxidative activity. In addition, the synergistic antioxidant effect of these compounds with alpha-tocopherol (vitamin E) in micelles was also studied by following the formation of linoleic acid hydroperoxides and the consumption of alpha-tocopherol. It was found that these compounds could not synergistically interact with alpha-tocopherol in micelles.

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Section: Resultsmentioning

confidence: 99%

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Dai

Chen

Zhou

et al. 2009

Phytotherapy Research

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“…That is, the antioxidants could reduce a-tocopheroxyl radical (TO . ) and regenerate TOH (Liu et al, 1988;Fang et al, 2002;Zhou et al, 2005a). Hence the inhibition time produced by the antioxidants and TOH when they were used in combination was longer than the sum of the inhibition times when the two antioxidants were used individually.…”

Section: Anti-hemolysis Effect Of Flavonols and Their Glycosides In Tmentioning

confidence: 90%

“…Its synergistic antioxidative effect with other antioxidants such as l-ascorbic acid (vitamin C) (Liu et al, 1988), green tea polyphenols (Jia et al, 1998;Zhou et al, 2000Zhou et al, , 2005aLiu et al, 2000) and resveratrol and its analogues (Fang et al, 2002) has been well documented. That is, the antioxidants could reduce a-tocopheroxyl radical (TO . )…”

Section: Anti-hemolysis Effect Of Flavonols and Their Glycosides In Tmentioning

confidence: 99%

Protective effects of flavonols and their glycosides against free radical-induced oxidative hemolysis of red blood cells

et al. 2006

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“…For example, ascorbic acid, a water soluble, chain-breaking antioxidant which inhibits the lipid peroxidation initiated in a water phase [82], is ineffective as an antioxidant for lipid peroxidation initiated in an oil phase, but synergistically interacts with the oil soluble antioxidant Vitamin E to inhibit this peroxidation [83,84]. Pryor et al [85] reported that lipophilic Scheme 18 Reaction mechanism of the amnoxyl radical with ascorbic acid by Liu et al [81].…”

Section: Scheme 15mentioning

confidence: 98%

Electron transfer reactions of piperidine aminoxyl radicals

Zhang

Liu

2010

Chin. Sci. Bull.

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This review article summarizes the electron transfer reactions of piperidine aminoxyl radicals. Electrochemical studies revealed the single electron transfer nature of piperidine aminoxyl radicals. In solution, piperidine aminoxyl radicals serve as single electron transfer oxidation reagent to react with various biologically interesting molecules such as glutathione, cysteine, ascorbic acid, and amines. The reaction product distribution, reaction kinetics, intermediates, and the reaction features in biological mimic environments including micelles and cyclodextrins were investigated. Oxoammonium salts, the one-electron transfer oxidation products of piperidine aminoxyl radicals, are agents of organic synthesis to selectively generate ketones or di-ketones from alcohols or ketones bearing α-methylene group under mild conditions. The new reactions of oxoammonium salts with aromatic amines, phenols, heterocycles including phenothiazines, papaverine, and bilirubin are also illustrated. aminoxyl radical, nitroxide, nitroxyl radical, iminoxyl radicals, oxoammonium salt, electron transfer, reduction and oxidation Citation:Zhang F, Liu Y C. Electron transfer reactions of piperidine aminoxyl radicals.

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Radical intermediates and antioxidant activity of ascorbic acid

Cited by 36 publications

References 97 publications

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Antioxidative effects of curcumin and its analogues against the free‐radical‐induced peroxidation of linoleic acid in micelles

Protective effects of flavonols and their glycosides against free radical-induced oxidative hemolysis of red blood cells

Electron transfer reactions of piperidine aminoxyl radicals

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