Gomphostenins: Two new antimalarial compounds from the leaves of Gomphostemma niveum

Phytochemical investigation of CHCl3 extract of the Gomphostemma niveum leaves led to the isolation of two new diterpene, compound 1 and 2. Their structures were elucidated by spectroscopic procedures and single crystal XRD. Compound 1 named as Gomphostenin 1 and structure was established as 8-ethyl (5H-furan2-one, 14-hydroxy, 2-oxo 3, 20 Z(17) diene clerodane, while compound 2 named as Gomphostenin-A; was found to be the acetyl derivative of compound 1 and revealed as 8-ethyl (5H-furan-2-one, 14-acetoxy, 2-oxo 3, 20 Z(17) diene clerodane. In vitro antimalarial activity against Plasmodium falciparum showed that compound 2 was more active than compound 1 and CHCl3 extract as well; with IC50 value of 3.4 mu g/mL. (C) 2009 Published by Elsevier Ltd.