Free Radical Scavenging Activity of Crude Extracts and 4´-O-Methylepigallocatechin Isolated From Roots of Cassine Transvaalensis Burtt-Davy from Botswana

Water and ethanol extracts of roots from Cassine transvaalensis Burtt-Davy (celastraceae) were assessed for in vitro antioxidant activity using 1,1- diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. The ethanolic extract exhibited higher free radical scavenging effect than the water extract at all tested concentrations. Above 100μg/ml, the ethanolic extract showed 80% scavenging activity, similar to control antioxidant compounds quercetin, rutin and L-ascorbic acid. The water extract reached a similar level of activity (80%) at 200μg/ml. Between 20-50μg/ml, 4 -O-methylepigallocatechin isolated by bioassay directed fractionation exhibited scavenging activity greater than that of either the ethanolic or aqueous crude extract. However, at concentrations above 50μg/ml, the scavenging activity of the ethanolic extract exceeded that of 4 -O-methyl-epigallocatechin.The results suggest that extracts from the roots of Cassine transvaalensis have strong antioxidant activity. These findings support the ethnomedical use of this plant to promote good health.