Activity of the Lupane isolated from Combretum leprosum against Leishmania amazonensis promastigotes

This paper describes the activity of the ethanolic extract (EE), obtained from the fruits of Combretum leprosum, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1) and its synthetic derivatives 1a-1d on Leishmania Amazonensis promastigotes. The EE displayed leishmanicidal activity and the IC50 was 24.8 μg mL-1. However, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1), at a concentration of 5.0 μg mL-1, showed a potent inhibitory activity on promastigotes proliferation (IC50 = 3.3 μg mL-1). Among the synthetic derivatives, only (1b) and (1d) were active against promastigotes (IC50 = 3.48 μg mL-1 and 5.8 μg mL-1, respectively). Moreover, the synthetic derivative 1a showed no activity on promastigotes of L. Amazonensis. EE, (1) and the synthetic derivatives 1a-1d showed no cytotoxic effect on mice peritoneal macrophages. These results provide evidence that the ethanolic extract and the lupane isolated from C. leprosum was active against promastigotes of L. amazonensis, and may be used as a tool in the studies of new antileishmanial drugs. (author)