Antioxidant reactions of alpha-tocopherolhydroquinone

alpha-Tocopherolhydroquinone (TQH(2)) is a product of alpha-tocopherol oxid ation/reduction that exerts antioxidant effects in biological systems. TQH( 2) inhibited autoxidation of methyl linoleate initiated by peroxyl radicals derived from thermolysis of 2,2'-azobis(2,4-dimethylvaleronitrile) in acet onitrile. TQH(2) oxidation yielded alpha-tocopherolquinone (TQ) as a major product and 2,3-epoxy-alpha-tocopherolquinone and 5,6-epoxy-alpha-tocophero lquinone as minor products. Each TQH(2) consumed approximately two peroxyl radicals in the course of the oxidation. The data suggest that TQH(2) scave nges peroxyl radicals primarily by electron transfer to form TQ and seconda rily by addition-elimination to form the epoxyquinones.