Antiviral activity of Embelia ribes Burm. f. against influenza virus invitro

AbstractViral respiratory infections are raising serious concern globally. Asian medicinal plants could be useful in improving thecurrent treatment strategies for influenza. The present study examines the activity of five plants from Bangladesh againstinfluenza virus. MDCK cells infected with influenza virus A/Puerto Rico/8/34 (H1N1) were treated with increasing concentrationsof ethyl acetate extracts, and their cytotoxicity (CC50), virus-inhibiting activity (IC50), and selectivity index (SI) werecalculated. The ethyl acetate extract of fruits of Embelia ribes Burm. f. (Myrsinaceae) had the highest antiviral activity, withan IC50of 0.2 ?g/mL and a SI of 32. Its major constituent, embelin, was further isolated and tested against the same virus.Embelin demonstrated antiviral activity, with an IC50of 0.3 ?M and an SI of 10. Time-of-addition experiments revealed thatembelin was most effective when added at early stages of the viral life cycle (0-1 h postinfection). Embelin was further evaluatedagainst a panel of influenza viruses including influenza A and B viruses that were susceptible or resistant to rimantadineand oseltamivir. Among the viruses tested, avian influenza virus A/mallard/Pennsylvania/10218/84 (H5N2) was the mostsusceptible to embelin (SI = 31), while A/Aichi/2/68 (H3N2) virus was the most resistant (SI = 5). In silico molecular dockingshowed that the binding site for embelin is located in the receptor-binding domain of the viral hemagglutinin. The results ofthis study provide evidence that E. ribes can be used for development of a novel alternative anti-influenza plant-based agent