Zinc pyrithione for COVID-19

As SARS-CoV-2 triggered a global health crisis, there is an urgent need to provide patients with safe, effective, accessible, and preferably oral therapeutics for COVID-19 that complement mRNA vaccines. Zinc compounds are widely known for their antiviral properties. Therefore, we have prepared a library of zinc complexes with pyrithione (1-hydroxy-2(1H)-pyridinethione) and its analogues, all of which showed promising in vitro inhibition of cathepsin L, an enzyme involved in SARS-CoV-2 entry, and PLPro, an enzyme involved in SARS-CoV-2 replication both in (sub)micromolar range. Zinc pyrithione 1a is a well-established, commercially available antimicrobial agent and was therefore selected for further evaluation of its SARS-CoV-2 entry and replication inhibition in an ex vivo system derived from primary human lung tissue. Our results suggest that zinc pyrithione complex 1a provides a multitarget approach to combat SARS-CoV-2 and should be considered for repurposing as a potential therapeutic against the insidious COVID-19 disease.

A large-scale screen to target SARS-CoV-2 The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome is initially expressed as two large polyproteins. Its main protease, M pro , is essential to yield functional viral proteins, making it a key drug target. Günther et al. used x-ray crystallography to screen more than 5000 compounds that are either approved drugs or drugs in clinical trials. The screen identified 37 compounds that bind to M pro . High-resolution structures showed that most compounds bind at the active site but also revealed two allosteric sites where binding of a drug causes conformational changes that affect the active site. In cell-based assays, seven compounds had antiviral activity without toxicity. The most potent, calpeptin, binds covalently in the active site, whereas the second most potent, pelitinib, binds at an allosteric site. Science , this issue p. 642