Oxidation products of cyanidin 3-O-beta-D-glucoside with a free radical initiator.

Recently, we have reported that anthocyanins show strong antioxidative activity, but no attention has been paid to anthocyanins from the viewpoint of the reaction mechanism of alkylperoxyl radicals; therefore, we investigated the reaction products of antioxidative anthocyanins (cyanidin 3-O-beta-D-glucoside). Cyanidin 3-O-beta-D-glucoside was reacted with 2,2'-azobis(2,4-dimet hylvaleronitrile) to generate the alkylperoxyl radicals, and the reaction products were isolated by high-performance liquid chromatography. The products were identified as 4,6-dihydroxy-2-O-beta-D-glucosyl-3-oxo-2,3-dihydroben-zofuran+ ++ and protocatechuic acid. Based on reaction products, the antioxidative mechanism of cyanidin 3-O-beta-D-glucoside may be different from that of alpha-tocopherol; cyanidin 3-O-beta-D-glucoside would produce another radical scavenger, as it would break down the structure and scavenge the radicals.