Corticosteroid Prednisolone and flavonoid Chrysin as drug candidates against SARS-CoV-2 replication: Computational and experimental findings

Abstract

Objectives: The rapid evolution of SARS-CoV-2 and the emergence of new variants have resulted in mutations in the Spike protein's receptor-binding domain (RBD), enhancing its binding affinity to the ACE2 receptor and increasing viral transmissibility. This study aims to identify inhibitors that can disrupt the Spike-ACE2 interaction, potentially preventing viral entry and immune evasion. The selected compounds may emerge as putative drugs following further studies. Methods: FDA-approved compounds were screened using molecular docking and molecular dynamics (MD) simulations to identify potential inhibitors of the Spike-ACE2 interaction. The most promising candidates were further validated through in vitro assays, including sandwich ELISA and Microscale Thermophoresis, to assess their ability to reduce Spike-ACE2 complex formation. The shortlisted compounds were tested in a cell-based viral culture system to evaluate their impact on SARS-CoV-2 replication. Results: Ten compounds were initially identified as potential inhibitors. Further in vitro validation narrowed the selection to five compounds that significantly reduced the formation of the Spike-ACE2 complex. Among them, Chrysin (a flavonoid) and Prednisolone (a corticosteroid) demonstrated the highest efficacy in suppressing the interaction, with IC50 values of 1.93 μM and 13.27 μM, respectively. Compounds could inhibit virus replication in the culture. Conclusions: Chrysin and Prednisolone emerged as the most effective inhibitors of the Spike-ACE2 interaction. Their potential to suppress SARS-CoV-2 replication suggests they could be valuable therapeutic candidates. Further studies, including animal model evaluations, are needed to explore their clinical applicability.