Abstract
Bioflavonoids are the largest group of plant-derived polyphenolic compounds with diverse biological potential and have also been proven efficacious in the treatment of Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). The present investigation validates molecular docking, simulation, and MM-PBSA studies of fifteen bioactive bioflavonoids derived from plants as a plausible potential antiviral in the treatment of COVID-19. Molecular docking studies for 15 flavonoids on the three SARS CoV-2 proteins, non-structural protein-15 Endoribonuclease (NSP15), the receptor-binding domain of spike protein (RBD of S protein), and main protease (M(pro)/3CL(pro)) were performed and selected protein-ligand complexes were subjected to Molecular Dynamics simulations. The molecular dynamics trajectories were subjected to free energy calculation by the MM-PBSA method. All flavonoids were further assessed for their effectiveness as adjuvant therapy by network pharmacology analysis on the target proteins. The network pharmacology analysis suggests the involvement of selected bioflavonoids in the modulation of multiple signaling pathways like p53, FoxO, MAPK, Wnt, Rap1, TNF, adipocytokine, and leukocyte transendothelial migration which plays a significant role in immunomodulation, minimizing the oxidative stress and inflammation. Molecular docking and molecular dynamics simulation studies illustrated the potential of glycyrrhizic acid, amentoflavone, and mulberroside in inhibiting key SARS-CoV-2 proteins and these results could be exploited further in designing future ligands from natural sources.