Antioxidan Activity on Six Species ofSterculiaceae Plants

Plants of Sterculiaceae have long been used as traditional medicines. Nine extracts of leaf; bark, and nuts of six Sterculiaceae species were evaluated for their antioxidant activity. Antioxidant activities tuere determined in vitro by free radical scavenging assqy using 2,2-diphenyl-1-picrylftydrazyl (DPPH) radical. Ascorbic acid was used as control. Among the 9 methanol extracts tested, 8 showed antiradical DPPH activities more than 50%, though still lower than the ascorbic acid. Material extracted from bark showed the highest activity, in which the extract of Pterospermum javanicum's bark produced the highest antioxidant activity (92.02%). Pftytochemical screening on three antioxidant compounds showed an association between the high antioxidant activities and the polyphenol compounds contained of theplant. Parts ofplants that contain medium to many po/yphenols, generallyhave antioxidant activity above 80%.