Highly selective antiplasmodial naphthylisoquinoline alkaloids from Ancistrocladus tectorius.

Naphthylisoquinoline alkaloids, named ancistectorine A1, N-methylancistectorine A1, ancistectorine A2, 5-epi-ancistectorine A2, ancistectorine A3, ancistectorine B1, and ancistectorine C1, have been isolated from twigs of the Chinese plant Ancistrocladus tectorius. The structural elucidation succeeded by chemical, spectroscopic, and chiroptical methods. Three of these compounds exhibited excellent, and specific, antiplasmodial activities, comparable with that of the as yet most active representative, dioncophylline C. Moreover, the antitumoral activities of two of the main alkaloids in this species was tested.