Discovery of Novel Natural Inhibitors Against SARS-CoV-2 Main Protease: A Rational Approach to Antiviral Therapeutics

Background/aim: The global pandemic caused by the novel SARS-CoV-2 virus underscores the urgent need for therapeutic interventions. Targeting the virus's main protease (Mpro), crucial for viral replication, is a promising strategy.

Objective: The current study aims to discover novel inhibitors of Mpro.

Methods: The current study identified five natural compounds (myrrhanol B (C1), myrrhanone B (C2), catechin (C3), quercetin (C4), and feralolide (C5) with strong inhibitory potential against Mpro through virtual screening and computational methods, predicting their binding efficiencies and validated it using the in-vitro inhibition activity. The selected compound's toxicity was examined using the MTT assay on a human BJ cell line.

Results: Compound C1 exhibited the highest binding affinity, with a docking score of -9.82 kcal/mol and strong hydrogen bond interactions within Mpro's active site. A microscale molecular dynamics simulation confirmed the stability and tight fit of the compounds in the protein's active pocket, showing superior binding interactions. in vitro assays validated their inhibitory effects, with C1 having the most significant potency (IC50 = 2.85 μM). The non-toxic nature of these compounds in human BJ cell lines was also confirmed, advocating their safety profile.

Conclusion: These findings highlight the effectiveness of combining computational and experimental approaches to identify potential lead compounds for SARS-CoV-2, with C1-C5 emerging as promising candidates for further drug development against this virus.