Design, synthesis and biological evaluation of esculetin derivatives as potential anti-HBV agents

Abstract A series of esculetin derivatives have been synthesized for the aim of exploring their anti-hepatitis B virus (anti-HBV) activity. In vitro anti-HBV activity was performed against HepG2.2.15 cells by using Elisa kit and cytotoxicity was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay with lamivudine as the positive control. The results demonstrated that several compounds showed moderate anti-HBV activity, while introduction of morpholine groups could significantly inhibit the expression of hepatitis B e antigen (HBeAg) and introduction of 2-methylimidazole group could significantly inhibit the expression of Hepatitis B surface antigen (HBsAg). Among all tested compounds, compound 4a demonstrated the best anti-HBeAg activity (IC50 = 15.8 ± 4.2 µM), while compound 6d demonstrated the best anti-HBsAg activity (IC50 = 21.4 ± 2.8 µM). Compounds 6b and 6c showed moderate anti-HBV activity and HBsAg inhibition. Compounds 4b showed moderate anti-HBV activity and inhibitory effect on HBeAg. In addition, compounds 4a, 4c, 4d, 6b, 6c and 6d showed improved metabolic stability. This study provides useful guidance for the discovery of anti-hbv drugs, which merits further investigation.