In vitro antimalarial activity of a Thai medicinal plant Picrasma javanica Bl

Picrasma javanica Bl., a medicinal plant used for the treatment of malaria in traditional medicine was evaluated for antimalarial activity. Primary screening demonstrated that the chloroform extract of the bark possessed the highest yield of antimalarial activity. Chemical isolation and purification of the active alkaloidal part yielded three different pure alkaloid components. Among these, one component was identified as the known major bark alkaloid, 4‐methoxy‐1‐vinyl‐β‐carboline, and a second new alkaloid, 6‐hydroxy‐4‐methoxy‐1‐vinyl‐β‐carboline. Complete characterization of the remaining alkaloid was not possible due to its inferior yield. The two identified alkaloids showed in vitro antimalarial activity against multi‐drug resistant Thai isolates of Plasmodium falciparum.