Numerous flavonoids were found to have antiviral effects against SARS-and MERS-CoV by mainly inhibiting the enzymes 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro).

This review is specifically focused on the search for flavonoids, polyphenolic compounds, which are proven to be effective against human CoVs. The latest progress in research to identify flavonoids for antiviral therapy are summarized and analyzed to propose strategies for future work on medicinal plants against coronaviruses such as SARS-CoV-2.

Quercetin, herbacetin, and isobavachalcone are discovered as the most promising flavonoids with anti-CoV potential.

Solnier J, Fladerer JP. Flavonoids: A complementary approach to conventional therapy of COVID-19? Phytochem Rev. 2020 Sep 18:1-23