PHYLLANTHUS AMARUS DOWN-REGULATES HEPATITIS-B VIRUS MESSENGER-RNA TRANSCRIPTION AND REPLICATION

The Phyllanthus amarus plant shows potential for treating hepatitis B virus. To define the mechanism of action of P. amarus, we used HepG2 2 .2.15 cells, which support hepatitis B virus replication. P. amarus in hibited hepatitis B virus polymerase activity, decreased episomal hepa titis B virus DNA content and suppressed virus release into culture me dium. To examine transcriptional control mechanisms, we used G26 hepat itis B virus transgenic mice, which produce serum HBsAg but neither HB cAg nor virion particles. When P. amarus was administered to transgeni c mice, hepatic HBsAg mRNA levels decreased, indicating transcriptiona l or post-transcriptional down-regulation of the transgene. Increase i n hepatitis B virus mRNA expression after stimulation of the glucocort icoid responsive element was also suppressed by P. amarus, suggesting involvement of the hepatitis B virus enhancer in this response. Disrup tion by P. amarus of hepatitis B virus polymerase activity, mRNA trans cription and replication supports its role as an antiviral agent.