Preprint / Version 1

Exploring nature’s bounty: identification of Withania somnifera as a promising source of therapeutic agents against COVID-19 by virtual screening and in silico evaluation

Authors

  • Aditi Srivastava aDepartment of Biochemistry, Era’s Lucknow Medical College and Hospital, Era University, Lucknow, UP, India
  • Sahabjada Siddiqui bDepartment of Biotechnology, Era’s Lucknow Medical College and Hospital, Era University, Lucknow, UP, India
  • Rumana Ahmad aDepartment of Biochemistry, Era’s Lucknow Medical College and Hospital, Era University, Lucknow, UP, India
  • Sudhir Mehrotra cDepartment of Biochemistry, University of Lucknow, Lucknow, UP, India
  • Bilal Ahmad dResearch Cell, Era’s Lucknow Medical College and Hospital, Era University, Lucknow, UP, India
  • A Srivastava eDepartment of Pathology, Era’s Lucknow Medical College and Hospital, Era University, Lucknow, UP, India

Keywords:

Withanolides, phytomedicine, SARS-CoV-2 target proteins, molecular docking, molecular chemoinformatics

Abstract

Coronaviruses are etiological agents of extreme human and animal infection resulting in abnormalities primarily in the respiratory tract. Presently, there is no defined COVID-19 intervention and clinical trials of prospective therapeutic agents are still in the nascent stage. Withania somnifera (L.) Dunal (WS), is an important medicinal plant in Ayurveda. The present study aimed to evaluate the antiviral potential of selected WS phytoconstituents against the novel SARS-CoV-2 target proteins and human ACE2 receptor using in silico methods. Most of the phytoconstituents displayed good absorption and transport kinetics and were also found to display no associated mutagenic or adverse effect(s). Molecular docking analyses revealed that most of the WS phytoconstituents exhibited potent binding to human ACE2 receptor, SAR-CoV and SARS-CoV-2 spike glycoproteins as well as the two main SARS-CoV-2 proteases. Most of the phytoconstituents were predicted to undergo Phase-I metabolism prior to excretion. All phytoconstituents had favorable bioactivity scores with respect to various receptor proteins and target enzymes. SAR analysis revealed that the number of oxygen atoms in the withanolide backbone and structural rearrangements were crucial for effective binding. Molecular simulation analyses of SARS-CoV-2 spike protein and papain-like protease with Withanolides A and B, respectively, displayed a stability profile at 300 K and constant RMSDs of protein side chains and Cα atoms throughout the simulation run time. In a nutshell, WS phytoconstituents warrant further investigations in vitro and in vivo to unravel their molecular mechanism(s) and modes of action for their future development as novel antiviral agents against COVID-19. Communicated by Ramaswamy H. Sarma Keywords: Withanolides, phytomedicine, SARS-CoV-2 target proteins, molecular docking, molecular chemoinformatics

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