Bioactive secondary metabolites from Salix tetrasperma Roxb.

Column chromatography of the light petroleum fraction from the methanolic extract of the stem bark of Salix tetrasperma Roxb. (Salicaceae) resulted in the isolation of beta-sitosterol acetate, friedelin, 3beta-friedelinol, beta-amyrin, beta-sitosterol, beta-sitosterol-O-glucoside in addition to palmitic acid. From the dichloromethane fraction of the leaves, catechol and tremulacin were isolated. Salicin and its derivatives tremuloidin and 2'-O-p-(E)-coumaroyl salicin were isolated from the ethyl acetate fraction of the leaves. The isolated compounds were identified by MS, and 1D NMR (1H and 13C) and 2D NMR (H-H COSY, HSQC, and HMBC) spectral analyses. The total methanolic extract exhibited significant anti-inflammatory activity (rat hind paw oedema). The extract with a content of 120 mg/kg body weight produced 52% inhibition equivalent to the standard diclofenac sodium (54% inhibition). The antioxidant (DPPH free radical scavenging) and analgesic activities, respectively, were also evaluated.