Antiviral activity of methyl helicterate isolated from Helicteres angustifolia (Sterculiaceae) against hepatitis B virus

The anti-HBV effect of methyl helicterate (MH), a triterpenoid isolated from the Chinese herb Helicteres angustifolia, was explored both in vitro and in vivo. In the HBV-transfected cell line HepG2.2.15, the secretion of HBsAg/HBeAg, the levels of HBV DNA and cccDNA, and the amount of viral RNA were significantly decreased after treatment with MH for 144 h. In addition, MH had no inhibitory effect on the mitochondrial DNA content. In DHBV-infected ducklings, MH significantly reduced the serum DHBV DNA, liver total viral DNA, and cccDNA levels. Furthermore, analysis of the liver pathological changes confirmed the hepatoprotective effect of MH. These results indicate that MH efficiently inhibits HBV replication both in vitro and in vivo and that MH may be a major bioactive ingredient in H. angustifolia.