OBJECTIVETo explore the effects of the extract from Phyllanthus urinaria L. on hepatitis B virus (HBV) replication and expression in HBV transient transfection model in vitro.

METHODSThe eukaryotic expression plasmid pHBV1.1, which contains 1.1-fold-overlength genome of HBV, was transfected into the human hepatoma cell line, HepG2, to establish and assess the HBV transient transfection model. The extract from Phyllanthus urinaria L. was prepared in different concentrations and methyl thiazolyl tetrazolium was used to detect the maximum nontoxic concentration of the drug. The extract from Phyllanthus urinaria L. were added into the transfected cell, at the concentrations of 0.8, 0.2 and 0.05 g/L, respectively. Four days after drug application, enzyme-linked immuno sorbent assay was used to detect the concentration of HBsAg in the supernatants, Southern blot was applied to analyze HBV DNA level, and Western blot was used to detect the expression of HBcAg in cells.

RESULTSAfter the transfection of plasmid pHBV1.1 into HepG2 cells, the concentration of HBsAg in supernatants was increased obviously as compared with that of the normal cells (P<0.05), and all expected HBV replicative intermediates were confirmed by Southern blot analysis, which ensured the successful establishment of the HBV transient transfection model. After the application of drugs at the concentrations of 0.8 and 0.2 g/L, the level of HBsAg was obviously decreased in the supernatants, as compared with that of the virus group (P<0.05); Southern blot showed that the level of HBV rc DNA, ds DNA, ss DNA was obviously reduced compared with that of the virus group (P<0.01); Western blot revealed that the expression of HBcAg in the drug group was obviously inhibited, as compared with that of the virus group (P<0.01).

CONCLUSIONSThe extract from Phyllanthus urinaria L. obviously inhibited replication and expression of HBV in HBV transfected cell lines in vitro, thus exerting distinctive anti-HBV effects.