Screening of Common Herbal Medicines as Promising Direct Inhibitors of Sars-Cov-2 in Silico

Background: Molecular docking has been used recently in pharma industry for drug designing, it’s a powerful tool to find ligand-substrate interactions at molecules level. Since urgent need to develop anti-viral drug that target new coronavirus main proteins, in silico docking has been used to achieve this purpose.

Materials and Methods: Thirteen herbs are known for their antioxidants and antiviral properties have been selected to investigate their abilities in inhibiting SARS-COV2 spike protein and main protease Mpro. pdb files for RBD (Receptor Binding Domain) region of spike protein and for Mpro and mol2 files for all herbs understudy were uploaded for swiss dock online server, the docking results were analyzed using chimera software. Full fitness energy and hydrogens bonds interactions were considered for docking evaluation. Pharma kinetic properties for compounds have good binding results were evaluated through AMES and ADMET tests.

Results: All compounds showed negative full fitness energy that means they are able to complex with both SARS-COV2 spike protein and main protease, however some of the herbs form very powerful hydrogen bonding with the RBD site of the spike protein and the catalytic site of Mpro such as coumarylquinic acid, while stigmasterol has strong binding with the spike protein only. Both compounds appear to be safe drugs for human according to AMES test results.

Conclusion: Coumarylquinic acid and stigmasterol have powerful binding in silico, further in vitro studies include using viral infected human lung cells and testing above compounds ability for inhibiting viral entry and replication should be proceed to confirm the study results.