In silico screening of known small molecules to bind ACE2 specific RBD on Spike Glycoprotein of SARS-CoV-2 for repurposing against COVID-19

Human coronavirus (SARS-CoV-2) is causing a pandemic with significant morbidity and mortality. Although, no effective novel drugs are available, drug repurposing is emerging as an effective strategy. In this study, we present an in silico drug repurposing study implementing successful concepts of computer aided drug design (CADD) technology with an objective to repurpose known drugs to interfere the viral cellular entry via the spike glycoprotein (SARS-CoV-2-S), which mediates the virus–cell receptor interaction. SARS-CoV-2-S uses ACE2 to enter cells. Totally, 4015 known and approved small molecules were screened for interaction with SARS-CoV-2 S through docking studies and 15 lead molecules were shortlisted. Further, three molecules streptomycin, ciprofloxacin and Glycyrrhizic acid (GA) were selected based on their reported anti-viral activity, safety, availability, affordability and subjected for Molecular Dynamics (MD) simulation. The MD simulation results indicate that GA from plant origin may be repurposed against SARS-CoV-2 and further studies are needed for validation.