ANTIOXIDATIVE PIGMENTS ISOLATED FROM THE SEEDS OF PHASEOLUS-VULGARIS L

Antioxidative activity of pea bean (Phaseolus vulgaris L.) extract was examined. A 0.5% TFA-80% ethanol extract prepared from red and black bean seed coat exhibited strong antioxidative activity, To determine the antioxidative role-of the pigments in the seed coats, the pigments, RP0 (cyanidin 3-O-beta-D-glucoside) and RP1 (pelargonidin 3-O-beta-D-glucoside) from red bean and BP1 (delphinidin 3-O-beta-D-glucoside) from black bean, were isolated.; RP0 showed strong antioxidative activity in the linoleic acid system at neutral condition (pH 7.0), while RP1 and BP1 exhibited no antioxidative activity at pH 7.0. In acidic conditions (pH 3.0 and 5.0), RP1 and BP1 showed strong antioxidative activity. The peak of RP0 at pH 7.0 in the linoleic acid system had disappeared in 10 days according to HPLC analysis. These results suggest that the antioxidative mechanism of RP0 may be different from that of RP1 and BP1.