Structure activity relationship studies on antileishmanial steroidal alkaloids from Sarcococca hookeriana

The search for antileishmanial constituents from the medicinal plant Sarcococca hookeriana ( Buxaceae) of Nepalese origin has resulted in the isolation of 17 ( 1-17) active steroidal alkaloids. Compounds 1, 2, and 10 were subjected to derivatization and five chemically derived derivatives ( 1a, 2a, 10a, 10b, 10c) were also obtained. All these natural compounds and derivatives were found to have potent to mild antileishmanial properties. The IC50 values were found to be in the range of 0.20-61.44 mu g mL(-1) 1 ( IC50 value of standard drug amphotericin B = 0.12 mu g mL(-1)). The structure activity relationship indicated that the varieties of functionalities present in ring A of the steroidal alkaloids were found to play a characteristic role to increase the antileishmanial activity.