Corilagin inhibits SARS-CoV-2 replication by targeting viral RNA-dependent RNA polymerase

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2) has become one major threat to human population health.The RNA-dependent RNA polymerase(RdRp) presents an ideal target of antivirals,whereas nucleoside analogs inhibitor is hindered by the proofreading activity of coronavirus.Herein,we report that corilagin(RAI-S-37) as a non-nucleoside inhibitor of SARS-CoV-2 RdRp,binds directly to RdRp,effectively inhibits the polymerase activity in both cell-free and cell-based assays,fully resists the proofreading activity and potently inhibits SARS-CoV-2 infection with a low 50% effective concentration(EC50) value of 0.13 μmol/L.Computation modeling predicts that RAI-S-37 lands at the palm domain of RdRp and prevents conformational changes required for nucleotide incorporation by RdRp.In addition,combination of RAI-S-37 with remdesivir exhibits additive activity against antiSARS-CoV-2 RdRp.Together with the current data available on the safety and pharmacokinetics of corilagin as a medicinal herbal agent,these results demonstrate the potential of being developed into one of the much-needed SARS-CoV-2 therapeutics.