Constituents from Megacarpaea delavayi Franch and their antimalarial activity.

One new indole alkaloid, 1-methoxy-6-hydroxy-3-indoleformic acid (1), seven known analogous alkaloids (2-8), and fourteen known phenolic compounds (9-22) were isolated from the whole plant of Megacarpaea delavayi Franch. Their structures were determined using extensive spectroscopic methods. All compounds were firstly reported from genus Megacarpaea. In vitro antimalarial activity of the compounds towards Plasmodium falciparum 3D7 strain were evaluated. Indole alkaloids 1-7 showed weak antimalarial activity towards P. falciparum strain 3D7 at 50 µM, with inhibition rates ranging from 19.7 ± 0.9% to 25.8 ± 1.5%, no activity was observed at 5 µM.