In vitro antimalarial activity of biflavonoids from Wikstroemia indica

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 mug/mL and 0.56 mug/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 I has remained unsettled, we confirmed the conformation by H-1- and C-13-NMR.