Redox Reactions of Tocopherol Monoglucoside in Aqueous Solutions

The reactions between tocopherol monoglucoside (TMG), a water-soluble vitamin-E derivative, with Br2· -, N3·, (SCN)2·-, NO2·, OH· and various halogenated peroxyl radicals were examined using a pulse radiolysis technique. The results demonstrate that TMG forms a stable phenoxyl radical at pH > 6.8...

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Bibliographic Details
Published in:Journal of radiation research 2002-01, Vol.43 (1), p.99
Main Authors: KAPOOR, SUDHIR, MUKHERJEE, TULSI, V. KAGIYA, TSUTOMU, KRISHNAN K. NAIR, CHERUPALLY
Format: Article
Language:English
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Summary:The reactions between tocopherol monoglucoside (TMG), a water-soluble vitamin-E derivative, with Br2· -, N3·, (SCN)2·-, NO2·, OH· and various halogenated peroxyl radicals were examined using a pulse radiolysis technique. The results demonstrate that TMG forms a stable phenoxyl radical at pH > 6.8. The thus-formed phenoxyl radical shows pH-dependent decay kinetics and is disproportionated by 2nd order kinetics at pH 2.3. It was observed that the TMG reactivity towards a halogenated peroxyl radical increases with the number of halogen atoms at the carbon atom having a peroxyl group. The reaction between the TMG phenoxyl radical and ascorbic acid was also examined using a pulse radiolysis technique. The results indicate that the TMG phenoxyl radical is repaired by ascorbate. Kinetic studies indicate that TMG may act as an antioxidant to repair free-radical damage to some biologically important compounds. The one-electron reduction potential for TMG was found to be 0.522 V ± 0.06 vs. NHE.
ISSN:0449-3060
1349-9157