Antioxidative activity and safety of 50% ethanolic red bean extract (Phaseolus radiatus L. var. Aurea)

This study evaluated the antioxidative activities of 50% ethanolic extract from red bean (Phaseolus radiatus L. var. Aurea). The antioxidative activities, including alpha,alpha-diphenyl-beta-picryl-hydrazyl (DPPH) radicals scavenging effects, Fe2+-chelating ability, and reducing power, were studied in vitro. The antioxidative activity was found to increase with the concentration of the extract to a certain extent and then level off as the concentration further increased. Compared with commercial antioxidants, the red bean extract showed less scavenging effect on the DPPH radical and less reducing power than alpha-Tocopherol and BHT, but better Fe2+-chelating ability. No mutagenic effect toward any tester strains was found in the 50% ethanolic extract of red bean.