Chlorogenic acid may be a potent inhibitor of dimeric SARS-CoV-2 main protease 3CLpro


Background: Since the emergence of coronavirus disease 2019 to date, there is no available approved drug or definitive treatment for coronavirus disease 2019 viral infection, and the identification of novel hits against therapeutic targets has become a global emergency. Echinacea purpurea is a traditional herb utilized to treat cough, fever, sore throat, respiratory tract infection, and so on as an immune stimulant. In this study, in silico molecular docking approach was used to screen phytocompounds from E. purpurea against severe acute respiratory syndrome coronavirus 2 main protease 3C-like protease (3CLpro) and severe acute respiratory syndrome coronavirus main peptidase (96% sequence similarity) to blunt the viral gene expression and viral replication. Methods: Initially, we screened phytocompounds for their druggability and ADMET property. Furthermore, x-ray crystallographic structures of main proteases 3CLpro and main peptidase having Protein Data Bank ID 6LU7 and 2GTB were used as protein targets for the identification of potential drug candidates. We performed docking using AutoDock Vina by PyRx 0.8 software. BIOVIA Discovery Studio Visualizer v2019 was used to analyze ligand-protein complex. The probable protein targets of the selected compound were predicted by BindingDB (P ≥ 0.7). STRING and Kyoto Encyclopedia of Genes and Genomes pathways are utilized to identify the molecular pathways modulated by the predicted targets (FDR ≤ 0.05), and the network interaction between compounds and protein pathways was constructed by Cytoscape 3.6.1. Results: Among all the compounds, chlorogenic acid showed druggable characteristics and scored the lowest binding energy with main protease and main peptidase via interacting with active site 1 domain amino acid residues. Interestingly, chlorogenic acid interacted with Phe140 main protease 3CLpro, which is potentially involved in the dimerization. Enrichment analysis identified chlorogenic acid to modulate insulin resistance, necroptosis, interleukin-17, tumor necrosis factor signaling pathway, legionellosis, T helper 17 cell differentiation, advanced glycation end products and receptor for advanced glycation end products, mitogen-activated protein kinase, Ras, estrogen, vascular endothelial growth factor, B-cell receptor, nuclear factor kappa B, Rap1, hypoxia inducible factor-1, phosphatidylinositide 3-kinase-Akt, insulin, mechanistic target of rapamycin, p53, retinoic acid inducible gene I like receptor, and ErbB signaling pathways. Conclusion: Chlorogenic acid may act as a potent main protease 3CLpro inhibitor and may also inhibit the severe acute respiratory syndrome coronavirus 2 dimerization, viral gene expression, and replication within the lung epithelium. Chlorogenic acid may go a long way in finding one of the multipronged solutions to tackle coronavirus disease 2019 viral infection in the future.