K.-G. LEE1, T. Shibamoto2, G. R. Takeoka3, J.-H. Kim4, and B.-S. Park4. (1) Dept. of Food Science & Technology, Dongguk Univ., Phil-dong, Jung-gu, Seoul, 100715, South Korea, (2) Dept. of Environmental Toxicology, Univ. of California, Davis, 1 Shields Ave., 4115 Meyer Hall, Davis, CA 95616, (3) Processed Foods Research Unit, USDA-ARS-Western Regional Research Center, 800 Buchanan St., Albany, CA 94710-1105, (4) School of Agricultural Biotechnology, Seoul National Univ., Seoul, 151-742, South Korea
The antioxidant activities of naturally occurring plant compounds were measured in a lipid peroxidation system consisting of ethyl arachidonate and Fenton's reagent. Inhibitory effects of 24 plant-derived flavonoids and 5 phenolic acids on malonaldehyde (MA) formation from ethyl arachidonate were examined using gas chromatography (GC) with a nitrogen-phosphorus detector (NPD). Luteolin, which showed the strongest antioxidant activity, inhibited MA formation by 94% and 97% at the levels of 0.5 and 1.0 mM, respectively. The antioxidant activities of the flavones and flavonols decreased in the following order: luteolin > rhamnetin > fisetin > kaempferol > morin > quercetin. Among the flavanones tested, hesperitin, taxifolin, and naringenin exhibited appreciable antioxidant activities (61-84%) at the 1.0 mM level. The inhibitory effect of epigallocatechin gallate (82.5% at the 1.0 mM level) was the strongest among the flavan-3-ols tested. Ferulic acid had the most potent antioxidant activity (74.6% at the 1.0 mM level) of the phenolic acids tested.
Session 33F, Nutraceuticals & Functional Foods: Antioxidants and phytochemical analysis