Free radical scavenging activity of crude extracts and 4´-o-methylepigallocatechin isolated from roots of cassine transvaalensis burtt-davy from botswana

Abstract

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. (Afr. J. Biomed. Res. 11: 55- 63) ots 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. (Afr. J. Biomed. Res. 11: 55- 63)Key Words; Cassine transvaalensis; antioxidant; DPPH radicals; 4’-O-methylepigallocatechin;epicatechin