Repurposing of Medicinal Plants Used in Siddha Formulations As Potential Protease Inhibitors of COVID 19: An in silico Approach

Background: The Coronavirus disease (COVID-19) caused by the virus SARS-CoV-2 has become a global pandemic in a short time has infected about 1,203,959 patients and brought forth death rate about 64,788 among 206 countries as mentioned by WHO in the month of April 2020. Currently, there is no specific treatment or vaccine for fighting against this infectious disease and scientists agree that possible therapeutic may arise through drug repositioning. Herbal medicine are achieving attention because of the extensive therapeutics like potent antiviral, immunomodulatory, anti-inflammatory, and anti-oxidant properties. Materials and methods: This study was planned to screen herbs from Siddha that have the potential to increase host immune system as well as blocking virus entry in host cells. Official Siddha formulation Kabasura Kudineer, Nilavembu Kudineer, and Novel Siddha formulation – JACOM are already being in use as antiviral, immunomodulatory, anti-inflammatory, and antioxidant. 54 molecules identified and surveyed via docking study. Docking study was performed using Maestro interface (Schrodinger Suite, LLC, NY). Results: Out of these 54 Phytoconstituents, 30 Phytoconstituents were found to interact with > 2 protein structures of COVID-19. The docking results indicate that amongst the reported molecules 4 out 5 protein structure (PDB ID: 5R7Y, 5R7Z, 5R80, 5R81 and 5R82) showed promising results of binding to COVID-19 enzyme. So this formulations may be useful as a therapeutic and/or prophylactic agent for restricting viral attachment to the host cells. Discussion: The drug repurposing study provide an insight in terms of binding of active ingredients present in different plants used in formulations and targets enzymes for treatment of the COVID19.