ABSTRACT
BACKGROUND: COVID-19 caused by SARS-CoV-2 infection has been spreading through many countries since the end of 2019. The 4th edition of the national guidelines for the management of COVID-19 provides an herbal formula with 9 herbs for its management. Aim of Study. We aimed to predict the mechanism of binding of SARS-CoV-2 and SARS-CoV spike glycoproteins with angiotensin-converting enzyme 2 (ACE2) to provide a molecular-level explanation of the higher pathogenicity of SARS-CoV-2 and to identify protein sites which may be targeted by therapeutic agents to disrupt virus-host interactions. Subsequently, we aimed to investigate the formula for the initial-stage management to identify a therapeutic agent with the most likely potential to become pharmaceutical candidate for the management of this disease. MATERIALS AND METHODS: GenBank and SWISS-MODEL were applied for model creation. ClusPro was used for protein-protein docking. PDBePISA was applied for identification of possible binding sites. TCMSP was employed for identification of the chemical compounds. AutoDock Vina together with PyRx was used for the prediction and evaluation of binding pose and affinity to ACE2. SwissADME and PreADME were applied to screening and prediction of the pharmacokinetic properties of the identified chemical compounds. PyMOL was used to visualise the structural models of SARS-CoV-2 and SARS-CoV spike glycoproteins complexed to ACE2 and to examine their interactions. RESULTS: SARS-CoV-2 had two chains (labelled chains B and C) which were predicted to bind with ACE2. In comparison, the SARS-CoV had only one chain (labelled chain C) predicted to bind with ACE2. The spike glycoproteins of both viruses were predicted to bind with ACE2 via position 487. Molecular docking screening and pharmacokinetic property prediction of the herbal compounds indicated that atractylenolide III (-9.1 kcal/mol) from Atractylodes lancea (Thunb.) Dc. (Cangzhu) may be a candidate therapeutic agent for initial-stage management. CONCLUSIONS: Atractylenolide III is predicted to have a strong binding affinity with ACE2 and eligible pharmacokinetic properties, anti-inflammatory effects and antiviral effects in in vitro study, and high distribution on the lungs in in vivo study.