Panduratin A from Boesenbergia rotunda suppresses hepatitis B virus by targeting HNF1α and synergizing with antiviral agents

Abstract

Background: Boesenbergia rotunda (fingerroot) is widely used in traditional medicine, and its bioactive compound panduratin A has demonstrated potent antiviral properties. However, the mechanistic basis underlying its anti-hepatitis B virus (HBV) activity remains to be fully elucidated. Methods: HBV-infected human hepatocytes (imHCs) were treated with B. rotunda extract, panduratin A, or pinostrobin. Intracellular HBV DNA, secreted HBsAg and HBeAg, and pregenomic RNA (pgRNA) were quantified in dose- and time-dependent experiments. Luciferase reporter assays were used to assess HBV promoter activity. The roles of HNF1α and HNF4α were evaluated by siRNA-mediated knockdown and ectopic gene expression. Drug interaction studies were performed using the KDM5 inhibitor GS-5801 and the capsid assembly modulator NVR-3778. A 3D liver spheroid model was used to validate antiviral effects on HBV DNA and cccDNA. Gene interaction network analysis was conducted to identify central regulatory pathways. Results: B. rotunda extract, panduratin A, and pinostrobin significantly suppressed intracellular HBV DNA, HBsAg, HBeAg, and pgRNA. Panduratin A exhibited the strongest antiviral activity and inhibited preS1, preS2, and core promoter activities. Panduratin A markedly downregulated HNF1α expression, with only modest effects on HNF4α. Knockdown of HNF1α significantly reduced the antiviral efficacy of panduratin A, whereas ectopic HNF1α expression rescued its inhibitory effects. Co-treatment with GS-5801 produced synergistic activity, and combination with NVR-3778 yielded additive antiviral effects. In 3D liver spheroids, panduratin A reduced intracellular HBV DNA and cccDNA with minimal cytotoxicity. Network analysis further identified HNF1α as a key regulatory node modulated by panduratin A. Conclusion: Panduratin A is a potent anti-HBV compound that acts primarily through HNF1α-dependent suppression of HBV transcription and replication. Its efficacy in combination therapy and in 3D liver models highlights its potential as a promising candidate for future HBV treatment strategies.