Antiplasmodial phenolic compounds from Piptadenia pervillei

Piptadenia pervillei Vatke (Fabaceae) was selected from a screening programme devoted to the search of naturally-occuring antimalarial compounds from plants of Madagascar. Bioassay-guided fractionation of the ethyl acetate extract of the leaves led to the isolation of four phenolic compounds, (+)-catechin (1), (+)-catechin 5-gallate (2), (+)-catechin 3-gallate (3) and ethyl gallate (4). Structures were determined by NMR and mass spectroscopy. Compounds 2 and 3 displayed the highest in vitro activity against the chloroquine-resistant strain FcB1 of Plasmodium falciparum with IC50 values of 1.2 μM and 1.0 μM, respectively, and no significant cytotoxicity against the human embryonic lung cells MRC-5 was measured (IC50 values > 75 μM). Five analogues (5-9) of (+)-catechin 5-gallate (2) were synthesized and evaluated for their antiplasmodial activity. © Georg Thieme Verlag KG Stuttgart.