Bioassay-guided isolation of anti-hepatitis B virus flavonoid myricetin-3-O-rhamnoside along with quercetin from Guiera senegalensis leaves
Mohammad Khalid Parvez, Mohammed S. Al‐Dosari, Ahmed H. Arbab, Adnan J. Al‐Rehaily, Mazin A. S. Abdelwahid
Abstract
Recently, we have shown in vitro anti-hepatitis B virus (HBV) activity of G. senegalensis J.F. Gmel leaves, and Identified quercetin and other flavonoids by HPTLC. Here we report bioassay-directed fractionation of G. senegalensis leaves using column chromatography and isolation of two flavonoinds from the n-butanol fraction, their structure determination (1H NMR, 13C NMR and 2D-NMR) and assessment of antiviral activities (HBsAg and HBeAg assay) in HBV-reporter HepG2.2.2.15 cells. Further molecular docking was performed against HBV polymerase (Pol/RT) and capsid (Core) proteins as well as host-receptor sodium taurocholate co-transporting polypeptide (NTCP). The two isolated bioactive compounds were identified as quercetin and myricetin-3-O-rhamnoside. Quercetin significantly inhibited synthesis of HBsAg and HBeAg by about 60% and 62%, respectively as compared to myricetin-3-O-rhamnoside by 44% and 35%, respectively. Molecular docking of the two anti-HBV flavonoids revealed their higher binding affinities towards Pol/RT than Core and NTCP. In conclusion, this is the first report on anti-HBV active myricetin-3-O-rhamnoside along with quercetin isolated from G. senegalensis leaves. Their possible mode of anti-HBV activities are suggested through binding with viral Pol/RT and Core as well as host NTCP proteins.