Antioxidant activity of sesame coat

The antioxidant activity of ethanolic extracts of sesame coat (EESC) was investigated. The antioxidant activity (91.4%) of 1.0 mg EESC was equal to 1.0 mg tocopherol (90.5%) but was weaker than 1.0 mg butylated hydroxyanisole (98.6%) on peroxidation of linoleic acid. EESC showed an inhibitory effect against the formation of thiobarbituric acid reactive substances (TBARS) in a liposome model system. EESC at 10.0 mg exhibited a 94.9% scavenging effect on alpha,alpha-diphenyl-beta-picrylhydrazyl radicals and marked reducing power, indicating that EESC acts as a primary antioxidant. The extracts, at a dose of 1.0 mg, showed a 50.0% scavenging effect on the hydroxyl radical. EESC also exhibited a metal-binding ability. Sesamin and sesamolin, the lignan substances, were found in EESC, by HPLC analysis. In addition, chromatographic analysis demonstrated that phenolic compounds and tetranortriterpenoids, which had positive reactions with beta-carotene, indicating antioxidant activity, are present in EESC. According to these results, termination of free radical reaction, metal-binding ability and quenching of reactive oxygen are suggested to be, in part, responsible for the antioxidant activity of EESC. (C) 2002 Elsevier Science Ltd. All rights reserved.