Scavenging of Benzylperoxyl Radicals by Carotenoids

Abstract

Carotenoids scavenge simple lipid-like alkylperoxyl radicals. However, the rate constant is too low to be determined directly and the mechanism is likewise not known with certainty [Mortensen, A. and Skibsted, L.H. (1998) FEBS Lett . 426 , 392-396]. It is demonstrated that carotenoids react with peroxyl radicals only slightly more reactive than lipidperoxyl radicals neither by electron transfer nor by hydrogen atom donation, but by adduct formation. Benzylperoxyl radicals are scavenged by the carotenoids &#103 -carotene and canthaxanthin with a second-order rate constant of at least 1 &#117 &#50 &#117 10 6 &#117 M &#109 1 &#117 s &#109 1 by formation of an adduct which decays in a first-order reaction.

• β-carotene
• Canthaxanthin
• Benzylperoxyl Radical
• Laser Flash Photolysis