New leishmanicidal stilbenes from a Peruvian folk medicine, Lonchocarpus nicou.

Two new stilbenes, 1 and 2, were isolated as leishmanicidal constituents from the methanolic extract of Lonchocarpus nicou leaves and stem, together with five known stilbenes and rotenoids. Their chemical structures were determined by spectral methods. Among them, the cis stilbene-type compounds 1 and 4 showed potent leishmanicidal activity (IC50: 5.5, 3.9 µg/mL), while the trans stilbene-type compounds 2 and 5, and rotenoids 6 and 7, showed moderate activities (IC50: 9.9, 12.8, 22.6, 19.6 µg/mL, respectively).