Molecular docking analysis of selected phytochemicals on two SARS-CoV-2 targets [version 1; peer review: 1 approved, 1 approved with reservations]

Background: The coronavirus spike (S) glycoprotein and M protease are two key targets that have been identified for vaccines and drug development against COVID-19. Methods: Virtual screening of some compounds of plant origin that have shown antiviral activities were carried out on the two targets, the M protease (PDB ID 6LU7) and S glycoprotein (PDB ID 6VSB), by docking with PyRx software. The binding affinities were compared with other compounds and drugs already identified as potential ligands for the M protease and S glycoprotein, as well as chloroquine and hydroxychloroquine. The docked compounds with best binding affinities were also filtered for drug likeness using the SwissADME and PROTOX platforms on the basis of physicochemical properties and toxicity, respectively. Results: The docking results revealed that scopadulcic acid and dammarenolic acid had the best binding affinity for the S glycoprotein and M pro protein targets, respectively. Silybinin, through molecular docking, also demonstrated good binding affinity for both protein targets making it a potential candidate for further evaluation as repurposed candidate for SARS-CoV-2, with likelihood of having multitarget activity as it showed activities for both targets. Conclusions: The study proposes that scopadulcic acid and dammarenolic acid be further evaluated in vivo for drug formulation against SARS-COV-2 and possible repurposing of Silybinin for the management of COVIV-19.