Antiplasmodial sesquiterpene alkaloids from the roots of maytenus mekongensis

Eight new sesquiterpene alkaloids (1 - 8) and four known sesquiterpene alkaloids (9 - 12) have been isolated from the roots of Maytenus mekongensis. Structures were determined using extensive spectroscopic methods. The relative configuration of 7-epi-mekongensine (2) was established by single-crystal X-ray crystallographic analysis. The alkaloids were evaluated for antiplasmodial activity against Plasmodium falciparum, K1 strain, and for cytotoxicity using a panel of cell lines.