Voacamine is an indole alkaloid derived from members of the Voacanga species, indigenous to Africa. In the Pacific region, voacamine was successfully isolated from the small tree, Voacanga papuana, indigenous to New Guinea by Ritchie and Taylor, University of Sydney, Australia in 1965. Voacamine enhances the cytotoxic effect of vinblastine against multidrug resistant KB cells. Voacamine enhances the cytotoxic effect of vinblastine against multidrug resistant KB cells, and is active against protozoa, including Plasmodium falciparum, Leishmania donovani and Trypanosoma cruzi, inhibiting protozoal topoisomerase IB.