Oxidized intermediates formed from α- and β-galactosyl ascorbic acid by pulse radiolysis

Abstract

The formation of OH-adduct radicals and the one-electron oxidation radicals of 6- O- α- and β-galactosyl ascorbic acid (α- and β-GA) were studied by pulse radiolysis. The OH-adduct radicals formed by the reaction between α- or β-GA and OH radicals were converted to their dehydrated radicals in neutral and alkaline solutions. The rate constants for reactions between OH radicals and α- or βGA were slightly smaller than that of ascorbic acid (AsA). The rate constants for the formation of oxidized radicals of GA with N 3 radicals were smaller than those of OH-adduct radicals. The rate constants for the decay of the α- or β-forms of galactosyl ascorbate radicals were twice as fast as that of AsA. The oxidized radicals of GA were found to decay by a disproportionation reaction on γ-ray irradiation.