A Drug Repurposing Approach Towards Elucidating the Potential of Flavonoids as COVID-19 Spike Protein Inhibitors

The novel coronavirus (nCoV) has emerged as a severe public health threat globally in the 21st century. Several therapies were reported towards identifying ligand against coronavirus, including targeting specific functional proteins or enzymes that are crucial to viruses, thereby preventing the synthesis and replication of virus RNA. Our study is mainly focused on targeting the virus's structural proteins, which could further block the binding of the virus to human cell receptors. In our study, we have selected nine Flavonoids for the inhibition of COVID-19 Spike protein, which have already been reported with their antiviral efficacies against other virus-infected diseases. AutoDock and PatchDock were used to study the inhibitory potential of flavonoids against COVID-19. Amongst all the eleven screened compounds, baicalin has depicted the highest binding affinity against 2019-nCoV spike glycoprotein. Additionally, we have also compared its potential with two standard HIV drugs Abacavir and hydroxychloroquine, and the docking results clearly revealed the better inhibitory potential of baicalin in comparison to recently used drug Abacavir and hydroxychloroquine for the treatment of COVID-19. Therefore our experimental findings strongly suggested that baicalin can be used as a potential inhibitor against COVID-19 spike protein, which could inhibit the interaction of the virus with the host cell and thus could provide a potential lead molecule for the development of a drug against COVID-19 disease.