Virtual Screening of Naturally Occurring Antiviral Molecules for SARS-CoV-2 Mitigation Using Docking Tool on Multiple Molecular Targets

The coronavirus catastrophe (COVID-19) caused by a novel strain of coronavirus (SARS-CoV-2) has turned the world upside down at an unprecedented level and has been declared as a pandemic by World Health Organization (WHO). It has resulted huge number of fatalities and infections due to the severe lower respiratory tract sickness in the infected people. Research across the world is in progress to identify inhibitors against various molecular targets associated with this viral infection. Among these targets, a very important one is a cysteine like protease or 3CL protease (3CLpro) and that is required for the replication of the virus. In the present study, initially we have investigated the potential of twenty naturally occurring antiviral molecules to function as inhibitors against the activity of main viral protease (3CLpro) so as to put a halt on viral replication. The investigation has been carried out through docking of the molecules with 3CLpro. Based on the results, three most potential molecules (bilobetin, ginkgetin and sciadopitysin) have been screened. Further these molecules were subjected for checking their activity on other molecular targets like a papain like protease (PLpro), spike protein S1, RNA dependent RNA polymerase (RdRp), angiotensin converting enzyme 2 (ACE2) receptor. In addition to 3CLpro inhibition, ginkgetin was predicted as an inhibitor of PLpro also. But none of these three compounds was found effective on rest other molecular targets.