Identification of Potential Phytochemical Inhibitors as Promising Therapeutics Against SARS-CoV-2 and Molecular Dynamics Simulation

The high infectivity and mortality of novel coronavirus has caused a serious concern all over the world. Still, there is no specific drug or preventive medication to treat SARS-CoV-2 infection despite comprehensive analysis by the researchers. This study was designed to demonstrate the efficacy of some phyto-chemical compounds against SARS-CoV-2 by using both structure and ligand based virtual screening methods. A total of 33 plant metabolites were screened against SARS-CoV-2 main protease proteins (MPP), Nsp9 RNA binding protein, spike receptor binding domain and HR2 domain using a molecular docking approach. Results showed that three metabolites, i.e., Limonin, Isoflavone, and Coumadin conferred maximum binding affinity with all key proteins of SARS-CoV-2. For each viral protein, the critical binding sites and drug surface hotspots have been unraveled. ADME analysis indicated that none of the compounds have adverse effects that could decrease their drug-like properties. Moreover, toxicity pattern analysis also unmasked the non-toxic nature of the top drug candidates. The RMSD values of top ligandmacromolecule complexes were less than 2 Å, while RMSF values showed regular atomic fluctuations in the molecular dynamics study. Notably, most of the target class by top drug candidates belonged to enzyme groups (e.g. oxidoreductases, protease, Kinase). Results of drug similarity prediction revealed two approved structural analogs of Coumadin named Warfarin (DB00682) and Phenprocoumon (DB00946) from DrugBank. In addition, Isoformononetin an experimental drug analog of isoflavone could also be an option for the treatment of viral infections. For limonin there was no analog found in drugbank. The study can pave the way for the creation of effective SARS-CoV-2 medications and preventive measures. We highly recommend further in vivo trials for the experimental validation of our findings