A METHOD OF SCREENING FOR ANTIOXIDANTS USING LIVER-CELL MEMBRANES PREPARED FROM TILAPIA OREOCHROMIS-NILOTICUS

Membrane fractions were prepared from tilapia Oreochromis niloticus li ver using differential centrifugation. Lipid peroxidation in the membr ane fractions was induced by incubation of equimolar solutions of ferr ous sulfate and ascorbic acid (FeAs) which generate hydroxyl anions. T he degree of lipid peroxidation was measured using the thiobarbituric acid method, and the potency of antioxidants was evaluated according t o inhibition of the lipid peroxidation induced by FeAs. The antioxidat ive activity of conventional antioxidants, such as butylated hydroxyan isole (BHA), alpha-tocopherol, and beta-carotene, were assayed using t he fish liver membrane fractions. BHA showed stronger antioxidative ac tivity than alpha-tocopherol, although the antioxidative activity of b eta-carotene could not be observed because of its insolubility. Moreov er, it was suggested that the fish liver membrane fractions were 11 to 12 times as sensitive as those of human and rat livers in detecting t he antioxidative activity of alpha-tocopherol. Therefore, tilapia live r may effectively be used for screening antioxidants owing to its grea ter sensitivity.