"experimentally validated inhibitors of SARS-CoV-2 main protease (Mpro) may provide an avenue for the identification of new lead compounds active against COVID-19."
https://pubs.acs.org/doi/10.1021/acs.jpclett.2c01193
Zinc 2+ ion inhibits SARS-CoV-2 main protease and viral replication in vitro
https://pubmed.ncbi.nlm.nih.gov/34514483/
"The protease of the human immunodeficiency virus is essential for replication of the virus, and the enzyme is therefore an attractive target for antiviral action. We have found that the viral protease is inhibited by approximately stoichiometric concentrations of copper"
https://pubmed.ncbi.nlm.nih.gov/2062837/
"The authors presented evidence for a mild effect of curcumin against SARS-CoV replication and the inhibitory effect of curcumin on SARS-CoV 3CL protease activity, which is essential for the replication of SARS-CoV."
https://www.frontiersin.org/articles/10.3389/fcell.2020.00479/full
"quercetin has the ability to inhibit the main protease of SARS-CoV-2, known as Mpro or 3CLpro (3C-like protease)"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066963/
Glycyrrhizin Effectively Inhibits SARS-CoV-2 Replication by Inhibiting the Viral Main Protease
https://pubmed.ncbi.nlm.nih.gov/33918301/