Bioactive flavones and biflavones from Selaginella moellendorffii Hieron.

Three new flavones named 5-carboxymethyl-4',7-dihydroxyflavone (1), its ethyl ester (2) and butyl ester (3) were isolated from the herb Selaginella moellendorffii Hieron., together with ten known compounds. Their structures were elucidated on the basis of spectroscopic and chemical analysis. Selected compounds were evaluated for their anti-HBV and cytotoxic activity. Among them, compounds 2 and 3 displayed inhibitory activity in vitro on hepatitis B virus (HBV) surface antigen (HBsAg) secretion of the Hep G2.2.15 cell line with IC(50) values of 0.17 mg/ml and 0.46 mg/ml, and on HBV e antigen (HBeAg) secretion with IC(50) values of 0.42 mg/ml and 0.42 mg/ml, respectively. Compounds 7, 8, 10 and 12 exhibited selective cytotoxicity against the three human cancer cell lines tested.