Duck hepatitis B virus model for screening of antiviral agents from medicinal herbs

The effects of the extracts of 20 Chinese medicinal herbs and an antiviral drug foscarnet on duck hepatitis B virus (DHBV) endogenous DNA polymerase (DNAp) activity were compared. The extracts of P. urinaria showed a dose-dependent inhibition on DHBV DNAp. And those of other herbs showed little inhibition effect. Primary duck hepatocyte (PDH) cultures were used for evaluating effects of the extract of P. urinaria, foscarnet and acyclovir (ACV) on DHBV, and all the drugs or the extracts showed inhibition of DHBV DNA replication. Furthermore, in vivo trials were carried out. Peking ducks infected with LJ-76 strain of DHBV were treated with the extract of P. urinaria or ACV and compared with placebo treated control ducks. The treatment results in the loss or reduction of circulating viral DHBV DNA and DHBsAg.