Relative Reactivity of Vitamin A vs. a Mixture of ß-Carotene Geometric Isomers with Electrochemically Generated Superoxide and Hydroperoxyl Radicals
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.
C. M. Collins et al., "Relative Reactivity of Vitamin A vs. a Mixture of ß-Carotene Geometric Isomers with Electrochemically Generated Superoxide and Hydroperoxyl Radicals," Electrochimica Acta, vol. 47, no. 4, pp. 567-576, Elsevier, Nov 2001.
The definitive version is available at https://doi.org/10.1016/S0013-4686(01)00776-9
Keywords and Phrases
Vitamin A; β-Carotene; Superoxide; Hydroperoxyl radicals; Kinetics; Simulations; Electrochemistry
International Standard Serial Number (ISSN)
Article - Journal
© 2001 Elsevier, All rights reserved.
01 Nov 2001