Grape compounds able to block a key enzyme in the Covid-19 virus

Researchers at North Carolina State University recently discovered that raw extracts of green tea, cocoa and two varieties of muscadine grapes (Vitis rotundifolia) harvested in the United States as table or wine grapes are also capable of inhibiting the function of SARS-Cov-2, which causes Covid-19.
In the study, the researchers performed both computer simulations and lab studies showing how the “main protease” (Mpro) in the SARS-CoV-2 virus reacted when confronted with a number of different plant chemical compounds already known for their potent anti-inflammatory and antioxidant properties.
“Mpro in SARS-CoV-2 is required for the virus to replicate and assemble itself,” Xie said. “If we can inhibit or deactivate this protease, the virus will die.”
Computer simulations showed that the studied chemical compounds from green tea, two varieties of muscadine grapes, cacao powder and dark chocolate were able to bind to different portions of Mpro.
In vitro lab experiments showed similar results. The chemical compounds in green tea and muscadine grapes were very successful at inhibiting Mpro’s function; chemical compounds in cacao powder and dark chocolate reduced Mpro activity by about half.
“Green tea has five tested chemical compounds that bind to different sites in the pocket on Mpro, essentially overwhelming it to inhibit its function,” Xie said. “Muscadine grapes contain these inhibitory chemicals in their skins and seeds. Plants use these compounds to protect themselves, so it is not surprising that plant leaves and skins contain these beneficial compounds.”
The American researchers say that flavanols and proanthocyanidins in grapes and wine prevent the SARS-CoV-2 virus from attaching itself to human cells. The polyphenols, which are also present in green tea and cocoa, could thus help in the fight against the pandemic.
Source: Yue Zhu, De-Yu Xie. Docking Characterization and in vitro Inhibitory Activity of Flavan-3-ols and Dimeric Proanthocyanidins Against the Main Protease Activity of SARS-Cov-2. Frontiers in Plant Science, 2020; 11.