Ebselen derivatives are very potent dual inhibitors of SARS-CoV-2 proteases - PL^proand M^proin in vitro studies

Proteases encoded by SARS-CoV-2 constitute a promising target for new therapies against COVID-19. SARS-CoV-2 main protease (M^pro, 3CL^pro) and papain-like protease (PL^pro) are responsible for viral polyprotein cleavage - a process crucial for viral survival and replication. Recently it was shown that 2-phenylbenzisoselenazol-3(2H)-one (ebselen), an organoselenium anti-inflammatory small-molecule drug, is a potent, covalent inhibitor of both the proteases and its potency was evaluated in enzymatic and anti-viral assays. In this study, we screened a collection of 23 ebselen derivatives for SARS-CoV-2 PL^proand M^proinhibitors. Our studies revealed that ebselen derivatives are potent inhibitors of both the proteases. We identified three PL^proand four M^proinhibitors superior to ebselen. Our work shows that ebselen constitutes a promising platform for development of new antiviral agents targeting both SARS-CoV-2 PL^proand M^pro.