Abstract
World is familiar with the viral pathogen Severe Acute Respiratory Syndrome Coronavirus 2 (SARS CoV-2). The principle working enzymes of SARS CoV-2 have been identified as main proteases 3Cl pro which act as main regulators for SARS infection. The need for therapy is required immediately pertaining to the vulnerable conditions. Protein-ligand studies are imperative for understanding the functioning of biological interactions as they are crucial in providing a hypothetical origin for the design and unearthing of novel drug targets. Phytoconstituents from Glycyrrhiza glabra, earlier reported to be anticancerous in nature were used as repurposed drugs against SARS CoV-2 main protease 3Clpro. We analyzed the molecular interactions of protein-phytocompounds, by AutoDock Vina 4.2 tools. The best interactions of each algorithm were subjected to molecular dynamic (MD) simulations to have an insight of the molecular dynamic mechanisms involved. Selected phytoconstituents gave a good score for binding affinity with the main protease 6LU7 of SARS CoV-2 as compared to the antiviral drugs already being used in the disease therapy. DehydroglyasperinC(-8.7,-8.1,-6.7,-7.1)kcal/mol, Licochalcone D(-8.4,-8.2,-7.1,-7.9) kcal/mol, Liquiritin(-8.6,-9.0,-7.2,-7.8) kcal/mol have showed energy interactions with 3Clpro better than many FDA approved repurposed drugs; Remdesvir, Favipiravir, and Hydroxychloroquine. MD Simulation also corelates our findings for molecular docking studies.