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 IC(50) values were found to be in the range of 0.20-61.44 microg mL(-1) (IC(50) value of standard drug amphotericin B = 0.12 microg 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.