Insights into the complexity of SARS-CoV-2 Mpro inhibition: Ebselen and its derivatives impair dimerisation of the enzyme

  • J Enzyme Inhib Med Chem. 2026 Dec;41(1):2604232. doi: 10.1080/14756366.2025.2604232.
Simone Fabbian  1 ,  Silvia Fabi  2 ,  Laurin Schwarz  1 ,  Giovanni Preto  1 ,  Chiara Schiavinato  1 ,  Cristiano Salata  2 ,  Letizia Crocetti  3 ,  Roberto Battistutta  4 ,  Barbara Gatto  1 ,  Alice Sosic  1
Affiliations
  • 1. Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy.
  • 2. Department of Molecular Medicine, University of Padova, Padova, Italy.
  • 3. NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Sesto Fiorentino, Italy.
  • 4. Department of Chemical Sciences, University of Padova, Padova, Italy.
PMID: 41481484 DOI: 10.1080/14756366.2025.2604232
Abstract

The SARS-CoV-2 Main Protease (Mpro), a key enzyme for viral replication, represents a highly attractive target for the development of broad-spectrum anti-coronavirus therapeutics. The organoselenium drug Ebselen has shown potent in vitro inhibition of Mpro as well as Antiviral activity, granting clinical interest as a COVID-19 treatment option. Here we show that Ebselen and selected derivatives with human neutrophil Elastase (HNE) inhibition and anti-radical activity are able to bind covalently to the viral enzyme with multiple stoichiometry, exhibiting inhibitory activity towards SARS-CoV-2 Mpro with potencies in the nanomolar range. Employing a mass spectrometry-based approach, we show that, upon binding to the target, Ebselen and its derivatives induce a dose-dependent shift in the dimer-monomer equilibrium, favouring the inactive monomeric state of the viral protease and possibly contributing to the observed in vitro inhibition.

Keywords
Ebselen; Mpro dimerization; SARS-CoV-2 Mpro; anti-coronavirus agents; organoselenium derivatives.
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