Fatty acid peroxyl radicals: Their generation and reactivities.

The formation and reactivity of fatty acid peroxyl radicals, obligatory intermediates in lipid peroxidation, are reviewed and new data, obtained by the pulse radiolysis technique, are presented. From previous studies employing steady-state systems for the generation of the peroxyl radicals, detailed mechanisms of the initial steps are known and a limited number of rate constants with phenolic antioxidants, including vitamin E (α-tocopherol), were determined - all in organic solvents. In contrast, pulse radiolysis allows the generation of the fatty acid peroxyl radicals as well as the determination of the rate constants of their reactions with each other and with phenolic antioxidants in aqueous solutions. Using kinetic modelling, we also calculated the rate constants for adduct formation between linoleic acid peroxyl radicals and aroxyl radicals derived from the flavonols kaempferol and quercetin