1,2,4-Thiadiazolidin-3,5-Diones as Inhibitors of Cysteine Proteases
Maria Aparecida Juliano, Marco Persico, Beatrice Severino, Giuseppe Tumbarello, Debora Okamoto, Karolina Rosa Fernandes, Gabriel Trigo, Aparecida Sadae Tanaka, José Thalles Lacerda, Oleh Tkachuck, Angela Corvino, Ferdinando Fiorino, Antonia Scognamiglio, Francesco Frecentese

TL;DR
This study explores a class of compounds that can both release hydrogen sulfide and inhibit key viral enzymes, suggesting potential for antiviral drug development.
Contribution
The study identifies specific thiadiazolidin-diones as potent and selective inhibitors of SARS-CoV-2 proteases.
Findings
THIA-6, -7, and -10 are the most potent inhibitors of SARS-CoV-2 3CLpro.
THIA-1, -2, and -8 show the highest selectivity against other proteases.
Computational studies support the compounds' inhibition mechanisms and guide future optimization.
Abstract
A focused library of 1,2,4-thiadiazolidin-3,5-diones (THIA-1–10), previously characterized as hydrogen sulfide (H2S) donors, was evaluated for inhibitory activity against cysteine proteases. We included two key cysteine proteases aiming at antiviral drug development—SARS-CoV-2 3CLpro (Mpro) and PLpro—alongside reference enzymes Papain and Cathepsin L. The compounds exhibited distinct selectivity profiles and inhibition mechanisms. The ability to act as covalent inhibitors of 3CLpro in the nanomolar range is of particular interest, with compounds THIA-6, -7, and -10 proving to be the most potent inhibitors of the series, and compounds THIA-1, -2, and -8 proving to be the most selective with respect to the other proteases. We explored the molecular bases of the observed activity profile of THIA-1–10 through computational studies, which supported and complemented the experimental findings,…
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Taxonomy
TopicsSynthesis and Characterization of Heterocyclic Compounds · Synthesis and biological activity · Click Chemistry and Applications
