Antimalarial activity of quassinoids against chloroquine-resistant Plasmodium falciparum in vitro.

The growth of Plasmodium falciparum in vitro was markedly inhibited by certain quassinoids (the bitter principles from plants of the family Simaroubaceae). The most active compound, simalikalactone D, gave complete inhibition at 0.005 microgram/ml. Glaucarubinone an soularubinone were equally effective at 0.006 microgram/ml, whereas chaparrinone and simarolide had little effect even at 0.01 microgram/ml. These relative activities are parallel to the antineoplastic activities of these materials.