Swerilactones A and B, Anti-HBV New Lactones from a Tradtional Chinese Herb: Swertia mileensis as a Treatment for Viral Hepatitis

Swerilactones A (1) and B (2), two novel lactones with an unprecedented 6/6/6/6/6 pentacyclic ring system, were isolated from the traditional Chinese herb of Swertia mileensis with activity against the hepatitis virus. Their structures and relative stereochemistry were elucidated based on spectroscopic methods and further confirmed by X-ray single crystal diffraction analysis. In vitro antihepatitis B virus (HBV) assay on Hep G 2.2.15 cell line showed that compound 1 inhibited HBsAg and HBeAg secretion with IC50 values of 3.66 and 3.58 mM, respectively.