Antioxidant activities of natural phenolic components from Dalbergia odorifera T. Chen

Abstract

The antioxidant activities on oil of natural phenolic components extracted from Dalbergia odorifera T. Chen were investigated. A new benzophenone 2,4-dihydroxy-5-methoxybenzophenone (1), together with eight known components, were isolated. The eight components were identified by chemical and spectroscopic methods as 2′,3′,7-trihydroxy-4′-methoxyisoflavanone (2), 3′-methoxydaidzein (3), 4′,5,7-trihydroxy-3-methoxyflavone (4), vestitol (5), medicarpin (6), hexanoic acid, 2-propenylester (7), hexadecanoic acid, ethyl ester (8) and 3,8,-nonadien-2-one (9). Their antioxidant activities were investigated and compared with butylated hydroxyluene (BHT) and α-tocopherol. The results showed that components 1, 3, 5 and 6 had antioxidant activity and components 2 and 4 had strong antioxidant activity at 0.02 and 0.04% levels. When the individual components (0.02%) were mixed with 0.02% BHT, or 0.02% α-tocopherol, their protection factor was increased, but there was no synergistic effect. When the individual component had 4 ppm added Fe3+, components 1, 2, 3 and 4 had antioxidant activity. Their antioxidant activities were tested by an oxidative stability instrument (OSI) at 100°C. Six of the phenolic components showed antioxidant activities.