Some quassinoids (1-6) isolated previously as plant growth inhibitors from the leaves of Eurycoma longifolia Jack. (Simaroubaceae) were subjected to in vitro tests on anti-tumor promoting, antischistosomal and plasmodicidal activities.
Eurycoma longifolia Jack., a plant in the family Simaroubaceae, is one of the most well known folk medicines for antipyretic, antimalarial and restorative activities in Southeast Asia, and is known to be a promising natural source of biologically active compounds. Some of the constituents have been known to possess antiamoebic, cytotoxic, antitumoral and plasmodicidal activities. In particular, the quassinoids are one of the major bioactive groups in this plant. Previously, we have isolated six quassinoids (Fig. 1) from E. longifolia during the course of the search for plant growth inhibitors occurring in the medicinal plants of Thailand. In this short communication, in vitro anti-tumor promoting, antischistosomal and plasmodicidal activities of these quassinoids are reported.