Potent anti-Ebola polyphenols indentified from maesa perlarius

Ebola virus disease (EVD), a disease caused by infection of Ebola virus (EBOV), is featured with hemorrhagic fever and high case fatality rate. Without specific drugs for the treatment of EBOV, patients largely rely on early supportive care. There are urgent needs to develop anti-Ebola therapeutics. Lingnan is a subtropical region in southern China with rich diversified plant species. In this study, over 500 extracts of the medicinal plants collected in Lingnan region were tested against the infection of Ebola pseudotyped particles using our established cell-based assay, which can be operated in BSL-2 containments 1. Maesa perlarius (SHA5) extracts was identified as an anti-Ebola active plant lead with an IC50 value of 0.52 pg/mL. The bioassay- guided fractionation of the plant extract afforded three proanthocyanidins [MP-1 (procyanidin B2), MP2 (procyanidin Cl) and MP-3 (epicatechin-(4β—>8)- epicatechin-(4β—>8)-epicatechin-(4β—>8)-epicatechin)], along with two flavan-3-ols [(+)-catechin) and (-)-epicatechin]. The anti-Ebola activity of the isolated compounds and their commercially available analogues were evaluated. The IC50 values of the compounds against pseudovirion HIV-Luc/EBOV-GP were tested to range from 0.91 µM to 42.7 µM. Among them, ASI1 and MP-1 were found to be the most potent ones. Molecular docking analysis suggested that these compounds were the potential ligands to Ebola glycoprotein. Overall, the current study explored the potential of proanthocyanidins as novel drug lead compounds to combat Ebola virus and provided basis for further study.