In silico screening, SAR and kinetic studies of naturally occurring flavonoids against SARS CoV-2 main protease

The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) pandemic has become a global challenge based on its replication within the host cells that relies on non-structural proteins, protease (M(pro)). Flavonoids, an important class of naturally occurring compounds with medicinal importance, are frequently available within fruits and vegetables. Herein, we report the in silico studies on naturally occurring flavonoids consisting of molecular docking studies and evaluation of theoretical kinetics. In this study, we prepared a library of nine different classes of naturally occurring flavonoids and screened them on Autodock and Autodockvina. The pharmacokinetic properties of most promising compounds have been predicted through ADMET SAR, inhibition constants, ligand efficiency and ligand fit quality have been worked out theoretically. The results revealed that naturally occurring flavonoids could fit well in the receptor's catalytic pocket, interact with essential amino acid residues and could be useful for future drug candidates through in vitro and in vivo studies. Moreover, MD simulation studies were conducted for two most promising flavonoids and the protein–ligand complexes were found quite stable. The selected natural flavonoids are free from any toxic effects and can be consumed as a preventive measure against SARS CoV-2.