Molecular docking analysis of selected phytochemicals against SARS-CoV-2 M^pro receptor

Presently world is on a war with the novel coronavirus and with no immediate treatments available the scourge caused by the SARS-CoV-2 is increasing day by day. A lot of researches are going on for the potential drug candidate that could help the healthcare system in this fight. Plants are a natural data bank of bioactive compounds. Many phytochemicals are being studied for various ailments including cancer, bacterial and viral infections, etc. The present study aims to screen 38 bioactive compounds from 5 selected plants viz., Azadirachta indica, Curcuma longa, Zingiber officinale, Ocimum basilicum and Panax ginseng against SARS-CoV-2. Lipinski's rule was taken as the foundation for initial screening. Shortlisted compounds were subjected to molecular docking study with M^pro receptor present in SARS-CoV-2. The study identified that gedunin, epoxyazadiradione, nimbin and ginsenosides have potential to inhibit M^pro activity and their binding energies are - 9.51 kcal/mol, - 8.47 kcal/mol, - 8.66 kcal/mol and - 9.63 kcal/mol respectively. Based on bioavailability radar studies gedunin and epoxyazadiradione are the two most potent compounds which are used for molecular dynamics simulation studies. Molecular dynamics studies showed that gedunin is more potent than epoxyazadiradione. To find the effectiveness and to propose the exact mechanism, in-vitro studies can be further performed on gedunin.