In Vitro Antimalarial Activity of Biflavonoids from Wikstroemia indica

Abstract

In our investigation of in vitro antimalarial screening of medicinal herbal extracts, the n-BuOH extract from the root of Wikstroemia indica showed a potent inhibitory effect. Fractionation of the active extract led to the isolation of two biflavonoids, sikokianin B (1) and sikokianin C (2) with IC50 values 0.54 μg/mL and 0.56 μg/mL, respectively, against the chloroquine-resistant strain of Plasmodium falciparum. This is the first report of the biological activity of 1 and 2. As the structure of 1 has remained unsettled, we confirmed the conformation by 1H-and 13C-NMR.