Molecular Docking, DFT and ADME-Toxicity Studies on Analogues of Epigallocatechin Gallate as SARS Coronavirus 3CL Protease Inhibitors

Severe acute respiratory syndrome (SARS) is a viral respiratory disease in humans which caused a pandemic outbreak in 2002–2003 with 8,422 cases and 916 deaths. The disease has been fully contained but it may still present in its natural host reservoirs in animal populations with the potential of returning into the human population in future. Thus, there is a requirement for designing new or novel class of inhibitors against this virus in future. The present study focus on the molecular docking studies of Epigallocatechin Gallate (EGCG) and its analogues against 3CL Protease enzyme of the virus. The 3CL Protease enzyme is responsible for the cleavages found at the N-terminus of replicase polyprotein. Earlier reports indicated EGCG as 3CL Protease inhibitors but with a low oral bioavailability and therefore required its molecular modification. In the present findings, the analogues bind at the active site binding cavity of the enzyme and these analogues have enhanced estimated pharmacological properties compared to EGCG. The investigation also focuses on the Density Function Theory (DFT) studies of the docked analogues and ADME-Toxicity prediction of the docked analogues revealing the docked analogues have enhanced pharmacological properties. The present investigation supports for the experimental testing of the analogues which would aid in a future SARS outbreak.