Title

Relative Reactivity of Vitamin A vs. a Mixture of ß-Carotene Geometric Isomers with Electrochemically Generated Superoxide and Hydroperoxyl Radicals

Abstract

The present study comprises a kinetic comparison of the reactivity of electrochemically generated superoxide, O2•-, and hydroperoxyl, HO2•, radicals toward a mixture of β-carotene geometric isomers versus all-trans-retinol (vitamin A). Rate constants were determined by computer simulation of experimental cyclic voltammetric data. It is reported that all-trans-retinol reacts more readily with both O2•- and HO2• than a mixture of geometric β-carotene isomers. Specifically, the latter is unreactive at ≤ 25 mM with O2•- within the timescale of cyclic voltammetry, while it reacts with HO2• at least an order of magnitude slower than all-trans-retinol. Our results indicate that all-trans-retinol is a better radical scavenger than a mixture of geometric β-carotene isomers and parallel the results of a recent epidemiological study which has shown that vitamin a may be a better anticarcinogenic agent than β-carotene.

Department(s)

Chemistry

Keywords and Phrases

Vitamin A; β-Carotene; Superoxide; Hydroperoxyl radicals; Kinetics; Simulations; Electrochemistry

International Standard Serial Number (ISSN)

0013-4686

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2001 Elsevier, All rights reserved.

Publication Date

01 Nov 2001

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