Molecular Docking Study of Several Seconder Metabolites from Medicinal Plants as Potential Inhibitors of COVID-19 Main Protease.

Objectives Coronaviruses (CoVs) cause infections that affect the respiratory tract, liver, central nervous, and the digestive systems in humans and animals. This study focused on the main protease (Mpro) in CoVs (PDB ID: 6LU7) that is used as a potential drug target to combat 2019-CoV. In this study, a total of 35 secondary metabolites from medical plants was selected and docked into the active site of 6LU7 by molecular docking studies to find a potential inhibitory compound that may be used to inhibit Coronavirus Disease-2019 (COVID-19) infection pathway. Materials and Methods The chemical structures of the ligands were obtained from the Drug Bank (https://www.drugbank.ca/). AutoDockTools (ADT ver. 1.5.6) was used for molecular docking studies. The docking results were evaluated using BIOVIA Discovery Studio Visualizer and PyMOL (ver. 2.3.3, Schrodinger, LLC). Results Pycnamine, tetrahydrocannabinol, oleuropein, quercetin, primulic acid, kaempferol, dicannabidiol, lobelin, colchicine, piperidine, medicagenic acid, and narcotine is found to be potential inhibitors of the COVID-19 Mpro. Among these compounds, pycnamine, which was evaluated against COVID-19 for the first time, showed a high affinity to the COVID-19 Mpro compared with other seconder metabolites and reference drugs. Conclusion Our results obtained from docking studies suggest that pycnamine should be examined in vitro to combat 2019-CoV. Moreover, pycnamine might be a promising lead compound for anti-CoV drugs.