TY - JOUR AB - The present study assessed the in vitro anti‑­hepatitis B virus (HBV) effects of cold‑adapted sea buckthorn (Hippophae rhamnoides). Sea buckthorn leaf ethanol extracts subjected to chloroform (SB‑Chl), ethyl acetate (SB‑Eac), n‑butanol (SB‑But) and aqueous (SB‑Aqu) fractionation were first examined (MTT assay) for their toxic effects on HepG2 cells. While SB‑Chl (IC50, 32.58 µg/ml) exhibited high cytotoxicity, SB‑Eac, SB‑But SB‑Aqu were non‑toxic at up to 150 µg/ml. High performance liquid chromatography analysis led to the identification of the anti‑HBV active flavonols, quercetin (93.09 µg/g), kaempferol (44.19 µg/g) and isorhamnetin (138.75 µg/g) in the extract. The analysis of the anti‑HBV effects of SB‑Eac, SB‑But and SB‑Aqu (50 µg/ml, each) on HepG2.2.15 cells revealed the marked inhibition of HBsAg and HBeAg expression levels. At the concentration of 10 µg/ml, quercetin and kaempferol exerted potent inhibitory effects on HBsAg (60.5 and 62.3%, respectively) and HBeAg synthesis (64.4 and 60.2%, respectively), as compared to isorhamnetin (30.5 and 28.4%, respectively). The HBV‑polymerase inhibitor drug, lamivudine (2 µM), inhibited HBsAg and HBeAg expression by 87.4 and 83.5%, respectively. The data were in good agreement with a previous in vitro and in silico molecular docking analysis performed by the authors where quercetin, kaempferol and lamivudine had formed stable complexes with HBV‑polymerase binding‑pocket amino acids. On the whole, to the best of our knowledge, the present study provides the first report of the anti‑HBV therapeutic potential of sea buckthorn, attributed to quercetin, kaempferol and isorhamnetin. AD - Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia AU - Parvez,Mohammad,K. AU - Al‑dosari,Mohammed,S. AU - Basudan,Omar,A. AU - Herqash,Rashed,N. DA - 2022/11/01 DO - 10.3892/br.2022.1573 IS - 5 JO - Biomed Rep KW - sea buckthorn hepatitis B virus anti‑hepatitis B virus quercetin kaempferol isorhamnetin PY - 2022 SN - 2049-9434 2049-9442 SP - 89 ST - The anti‑hepatitis B virus activity of sea buckthorn is attributed to quercetin, kaempferol and isorhamnetin T2 - Biomedical Reports TI - The anti‑hepatitis B virus activity of sea buckthorn is attributed to quercetin, kaempferol and isorhamnetin UR - https://doi.org/10.3892/br.2022.1573 VL - 17 ER -