Abstract: biomedicines Article Interaction of Epigallocatechin Gallate and Quercetin with Spike Glycoprotein (S-Glycoprotein) of SARS-CoV-2: In Silico Study Mehran Alavi 1,2, * , M. R. Mozafari 3, * , Saba Ghaemi 4 , Morahem Ashengroph 1 , Fatemeh Hasanzadeh Davarani 5 and Mohammadreza Mohammadabadi 6 1 2 3 4 5 6 * Citation: Alavi, M.; Mozafari, M.R.; Ghaemi, S.; Ashengroph, M.; Hasanzadeh Davarani, F.; Mohammadabadi, M. Interaction of Epigallocatechin Gallate and Quercetin with Spike Glycoprotein (S-Glycoprotein) of SARS-CoV-2: In Silico Study. Biomedicines 2022, 10, 3074. https://doi.org/10.3390/ biomedicines10123074 Academic Editor: Santiago Garcia-Vallve Received: 11 October 2022 Accepted: 19 November 2022 Published: 29 November 2022 Department of Biological Science, Faculty of Science, University of Kurdistan, Kurdistan 6617715175, Iran Nanobiotechnology Department, Faculty of Innovative Science and Technology, Razi University, Kermanshah 6714414971, Iran Australasian Nanoscience and Nanotechnology Initiative (ANNI), Monash University LPO, Clayton, VIC 3168, Australia Research Committee of Medical School, Alborz University of Medical Science, Karaj 3149779453, Iran Department of Plant Pathology, Rafsanjan Branch, Islamic Azad University, Rafsanjan 7718897111, Iran Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman 7616913439, Iran Correspondence: mehranbio83@gmail.com (M.A.); dr.m.r.mozafari@gmail.com (M.R.M.) Abstract: Severe acute respiratory syndrome (SARS)-CoV-2 from the family Coronaviridae is the cause of the outbreak of severe pneumonia, known as coronavirus disease 2019 (COVID-19), which was first recognized in 2019. Various potential antiviral drugs have been presented to hinder SARSCoV-2 or treat COVID-19 disease. Side effects of these drugs are among the main complicated issues for patients. Natural compounds, specifically primary and secondary herbal metabolites, may be considered as alternative options to provide therapeutic activity and reduce cytotoxicity. Phenolic materials such as epigallocatechin gallate (EGCG, polyphenol) and quercetin have shown antibacterial, antifungal, antiviral, anticancer, and anti-inflammatory effects in vitro and in vivo. Therefore, in this study, molecular docking was applied to measure the docking property of epigallocatechin gallate and quercetin towards the transmembrane spike (S) glycoprotein of SARS-CoV-2. Results of the present study showed Vina scores of −9.9 and −8.3 obtained for EGCG and quercetin by CB-Dock. In the case of EGCG, four hydrogen bonds of OG1, OD2, O3, and O13 atoms interacted with the Threonine (THR778) and Aspartic acid (ASP867) amino acids of the spike glycoprotein (6VSB). According to these results, epigallocatechin gallate and quercetin can be considered potent therapeutic compounds for addressing viral diseases. Keywords: SARS-CoV-2; transmembrane spike glycoprotein; severe pneumonia; natural compounds; antiviral activity Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil-