Measurement of antioxidative activity in metal ion-induced lipid peroxidation systems

This study aims to investigate the acceleration effects of various prooxidants on linoleic acid peroxidation and to assess the feasibility of applying these model systems by measuring the antioxidant activities of butylated hydroxyanisole (BHA), alpha-tocopherol and rosemary extracts. According to our results, Fe2+ and Fe3+ exhibited more stimulatory effects than other prooxidants on the peroxidation of linoleic acid. An additional amount of ascorbic acid can reduce Fe3+ to Fe2+, resulting in more severe peroxidation. However, ascorbic acid displays antioxidant activity with increasing concentration. The peroxidation of linoleic acid induced by Fenton reaction is less than that induced by iron ions and was increased by addition of ascorbic acid to the system to maintain the regeneration of Fe2+ and the production of hydroxyl radicals. BHA shows the strongest inhibitory effects on the peroxidation of linoleic acid in all systems. The antioxidant activity of alpha-tocopherol is less than that of rosemary extracts in the iron ion-induced peroxidation systems. However, alpha-tocopherol shows stronger inhibitory effects than rosemary extracts in the Fenton reaction-induced peroxidation system at a concentration less 100 mg kg(-1). These systems cain be useful in screening antioxidants from natural sources because of the short reaction time and clear difference between each antioxidant. (C) 1999 Society of Chemical Industry.