Ebola Entry Inhibitors Discovered from .

Ebola virus disease (EVD), a disease caused by infection with Ebola virus (EBOV), is characterized by hemorrhagic fever and a high case fatality rate. With limited options for the treatment of EVD, anti-Ebola viral therapeutics need to be urgently developed. In this study, over 500 extracts of medicinal plants collected in the Lingnan region were tested against infection with Ebola-virus-pseudotyped particles (EBOVpp), leading to the discovery of as an anti-EBOV plant lead. The methanol extract (MPBE) of the stems of this plant showed an inhibitory effect against EBOVpp, with an IC value of 0.52 µg/mL, which was confirmed by testing the extract against infectious EBOV in a biosafety level 4 laboratory. The bioassay-guided fractionation of MPBE resulted in three proanthocyanidins (procyanidin B2 (), procyanidin C1 (), and epicatechin-(4→8)-epicatechin-(4→8)-epicatechin-(4β→8)-epicatechin ()), along with two flavan-3-ols ((+)-catechin () and (-)-epicatechin ()). The IC values of the compounds against pseudovirion-bearing EBOV-GP ranged from 0.83 to 36.0 µM, with as the most potent inhibitor. The anti-EBOV activities of five synthetic derivatives together with six commercially available analogues, including EGCG ((-)-epigallocatechin-3--gallate ()), were further investigated. Molecular docking analysis and binding affinity measurement suggested the EBOV glycoprotein could be a potential molecular target for and its related compounds.