Both Baicalein and Gallocatechin Gallate Efficaciously Inhibit SARS-CoV-2 Replication by Targeting Mpro and Sepsis in Mice

Abstract Severe acute syndrome coronavirus 2(SARS-CoV-2) caused the global pandemic of COVID-19 since December 2019. Although most of COVID-19’s patients are mild or common, most of the severe patients have sepsis caused by the cytokine storm, which greatly increases the case fatality rate. Moreover, there is no effective drug that can resist the novel coronavirus so far, so it’s urgent to develop antiviral drug for the SARS-CoV-2. In our research, we screened 29 compounds with a score lower than -6 from 35 flavonoid compounds by molecular docking. (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were identified to have potent inhibit activity with IC50 5.774±0.805μM, 13.14±2.081μM and 5.158±0.928μM by FRET assay. Subsequently, we conducted molecular docking experiments, which showed that (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were non-covalently bound to Mpro through π-π stacking and hydrogen bonds in the Cys145 catalytic site. We further evaluated the effect of (-)-Gallocatechin gallate and Baicalein on cytokine storm use a mouse model of sepsis. (-)-Gallocatechin gallate and Baicalein significant reduced sepsis severity based on weight, murine sepsis score and survival rate and reduced the inflammatory factors level such as TNF-α, IL-1α, IL-4 and IL-10. Overall, (-)-Gallocatechin gallate and Baicalein may be potential drugs for symptomatic treatment of COVID-19.