New Anti-HBV C-Boivinopyranosyl Flavones from Alternanthera philoxeroides.

C-boivinopyranosyl flavones have rarely been isolated from nature. In the search for anti-HBV (hepatitis b virus) constituents of Alternanthera philoxeroides, two new compounds, luteolin-6-C-β-D-boivinopyranosyl-3'-O-β-D-glucopyranoside (1) and chrysoeriol-6-C-β-D-boivinopyranosyl-4'-O-β-D-glucopyranoside (2), along with three known C-boivinopyranosyl flavones (compounds 3-5) were isolated. Their structures were determined by spectroscopic analyses including 1D and 2D NMR, HR-ESI-MS, IR spectra. Compounds 1, 2 and 3 showed significant anti-HBV activities through specifically inhibiting the secretion of HBsAg in HepG2.2.15.