New antimalarial and cytotoxic sungucine derivatives from Strychnos icaja roots

Reinvestigation of Strychnos icaja Baillon resulted in the isolation of vom icine, isostrychnine and of three new sungucine derivatives, named isosungu cine (8), 18-hydroxy-sungucine (9) and 18-hydroxy-isosungucine (10). They w ere identified by detailed spectroscopic methods. The complete H-1- and C-1 3-NMR study of sungucine was also realized. Some of these compounds were hi ghly active against Plasmodium falciparum in vitro and more particularly ag ainst the chloroquine-resistant strain. Compound 10 showed a selective anti plasmodial activity, with >100-fold greater toxicity towards Plasmodium fal ciparum, relative to cultured human cancer cells (KB and HeLa lines) or fib roblasts (W138).