Sophoranone A and B: two new cytotoxic prenylated metabolites and their analogs from the root bark of Sophora flavescens

Sophora flavescens Ait. has been utilized as an anticarcinogen, antibacterial and insecticide. Two new prenylflavonoids, Sophoflavonoid A (1) and Sophoflavonoid B (2), together with four known analogues were isolated from the root bark of S. flavescens. The structures of these compounds were elucidated by the interpretation of spectroscopic data and chemical evidence. Their absolute configurations were determined by ECD analysis. The inhibitory effects of compounds 1-6 against three lung carcinoma cells were determined using the MTT assay. The results revealed that compound 3 displayed strong cytotoxic effect against H460 cell line (IC50, 4.67 mu M), while compounds 1, 4-6 exhibited significant inhibitory effects against three tumor cells. Therefore, this study suggests that the isopentenyl flavonoid-rich products of S. flavescens, including the new compounds, could be valuable candidates for the development of pharmaceuticals in the prevention and treatment for tumors.