Lignans with anti-hepatitis B virus activities from Phyllanthus niruri L.

One new lignan, nirtetralin B, along with its two known stereoisomers were isolated from Phyllanthus niruri L. The structure of the new compound was determined by spectroscopy experiments and x-ray diffraction analysis. These lignans were assayed for anti-hepatitis B virus activities in vitro. Nirtetralin and nirtetralin A, B effectively suppressed the secretion of the HBV antigens in a dose-dependent manner with IC₅₀ values for HBsAg of 9.5 µM (nirtetralin A), 16.7 µM (nirtetralin B) and 97.2 µM (nirtetralin), IC₅₀ values for HBeAg of 17.4 µM (nirtetralin A), 69.3 µM (nirtetralin B) and 232.0 µM (nirtetralin), respectively.