Four compounds were isolated from the petroleum ether and ethyl acetate extracts of the stem bark of Hopea scaphula Roxb. The structures of the isolated compounds were elucidated as stigmasterol (1), 1,2- dimethoxy-4-allylbenzene (2), 3,4-dimethoxycinnamaldehyde (3) and fi-amyrin (4) by extensive spectroscopic studies. The isolated compounds and crude extracts were subjected to antioxidant screening through free radical scavenging activity by DPPH (1, 1-diphenyl-2-picrylhydrazyl), where compounds 1 and 2 showed substantial antioxidant activity with IC50 value 18.0 and 63.0 fig/ml, respectively. In case of fi-glucosidase inhibition assay, the ethyl acetate extract revealed strong inhibitory activity (94.18%) while the petroleum ether extract showed 79.11% enzyme inhibition. This is the first report of antioxidant and fi-glucosidase inhibitory activities of H. scaphula Roxb.
Keywords: Hopea scaphula Roxb., Dipterocarpaceae, Stigmasterol, 1,2-dimethoxy-4-allylbemene, 3,4-dimethoxycinnamaldehvde, f-anivrin, Antioxidant, fl-gliicosidase inhibition