Action of quinolinic and indolinonic aminoxyls as radical-scavenging antioxidants

The kinetic studies on the actions of quinolinic and indolinonic aminoxyls in the oxidation of lipid peroxidation induced by free radicals were carrie d out to evaluate their antioxidant activity. These aminoxyls showed a simi lar reactivity toward peroxyl radical with alpha-tocopherol. The antioxidan t efficacies of aminoxyls against oxidation of methyl linoleate in homogene ous solution were smaller than that of alpha-tocopherol. Hydroxylamine, a r educed form of aminoxyl, possessed a comparative antioxidant efficacy with alpha-tocopherol and was capable of suppressing the consumption of alpha-to copherol. Aminoxyls showed more potent antioxidant activity than alpha-toco pherol against the oxidation of methyl linoleate micelles induced by peroxy l radical or by a combination of copper ion and hydrogen peroxide. These re sults suggest that quinolinic and indolinonic aminoxyls may act as potent a ntioxidants against lipid peroxidation, especially in the presence of a goo d reductant which reduces aminoxyl radicals to hydroxylamines. (C) 1999 Els evier Science Ireland Ltd. All rights reserved.