Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Antimicrobial Agents and Chemotherapy 4393-4398 2009 PAR00004140 ENG Antimicrobial Agents and Chemotherapy 0066-4804 ISI:000270020600047 10 10.1128/aac.00951-09 https://www.documentation.ird.fr/hor/PAR00004140 https://www.documentation.ird.fr/intranet/publi/2024-01/010086178.pdf 53 Horizon (IRD) We report the isolation and identification of a new quassinoid named simalikalactone E (SkE), extracted from a widely used Amazonian antimalarial remedy made out of Quassia amara L. (Simaroubaceae) leaves. This new molecule inhibited the growth of Plasmodium falciparum cultured in vitro by 50%, in the concentration range from 24 to 68 nM, independently of the strain sensitivity to chloroquine. We also showed that this compound was able to decrease gametocytemia with a 50% inhibitory concentration sevenfold lower than that of primaquine. SkE was found to be less toxic than simalikalactone D (SkD), another antimalarial quassinoid from Q. amara, and its cytotoxicity on mammalian cells was dependent on the cell line, displaying a good selectivity index when tested on nontumorogenic cells. In vivo, SkE inhibited murine malaria growth of Plasmodium vinckei petteri by 50% at 1 and 0.5 mg/kg of body weight/day, by the oral or intraperitoneal routes, respectively. The contribution of quassinoids as a source of antimalarial molecules needs therefore to be reconsidered. 076 ; 052 UR152