Design, synthesis, and biological activity evaluation of dihydromyricetin derivatives against SARS-CoV-2-Omicron virus.

An oxidising and substituting one-pot reaction strategy has been developed to synthesise dihydromyricetin derivatives with the aim of enhancing the inhibitory activity of dihydromyricetin against SARS-CoV-2. Different ω-methoxy-ω-oxeylkyl was introduced in C₇-OH site and yielded eight analogs, all of them showed good inhibitory activity against SARS-CoV-2 3CL^pro with IC₅₀ values ranging from 0.72 to 2.36 μM. In the Vero E6-cell, compound 3 has a good activity of anti-SARS-CoV-2 virus (Omicron virus BA.5) in the prevention model, with an EC₅₀ of 15.84 μM, and so do compound 10 in the therapeutic model, with an EC₅₀ of 11.52 μM. The results suggest that the introduction of long chain ω-oxeylkyl at C₇-OH facilitate the inhibition of viral replication in the therapeutic model, which is consistent with the binding energies predicted from molecular docking conclusions. It implies that dihydromyricetin derivatives have the potential to become effective inhibitors of SARS-CoV-2 Omicron and other viruses.