These foods contain nutrients that can inhibit a key SARS-CoV-2 enzyme needed for the COVID virus to replicate

Chemicals in foods or drinks like green tea, muscadine grapes, and dark chocolate can bind to and block the function of a particular enzyme or protease. SARS-CoV-2 virus, according to a new study by plant biologists at North Carolina State University.

Proteases are important for the health and viability of cells and viruses, says De-Yu Xie, professor of plant and microbial biology at NC State and corresponding author of the study. If proteases are inhibited, cells cannot perform many important functions – such as replication, for example.

“One of the goals of our lab is to find nutraceuticals in foods or herbal medicines that inhibit the way a virus attaches to human cells or the spread of a virus in human cells,” Xie said.

In the study, NC state researchers performed both computer simulations and laboratory studies showing how the so-called “main protease” (M^pro) in the SARS-CoV-2 virus reacted to a number of plant chemical compounds already known for their potent anti-inflammatory and antioxidant properties.

“M^pro in SARS-CoV-2 is necessary for the virus to replicate and assemble, ”Xie said. “If we can inhibit or deactivate this protease, the virus will die.”

Computer simulations have shown that the chemical compounds studied in green tea, two varieties of muscadine grapes, cocoa powder and dark chocolate were able to bind to different portions of M.^pro.

“M^pro has a part that looks like a “pocket” that has been “filled in” by the chemical compounds, “Xie said. “When this pocket was filled, the protease lost its important function.”

In vitro laboratory experiments performed by Yue Zhu, PhD in North Carolina. student in Xie’s lab, showed similar results. Chemicals in green tea and muscadine grapes have been very successful in inhibiting M^prothe function of; chemicals in cocoa powder and dark chocolate reduces M^pro activity of about half.

“Green tea has five tested chemicals that bind to different sites in the pocket on M^pro, essentially submerging 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’s no surprise that the leaves and skins of plants contain these beneficial compounds.

The paper appears in Frontiers of phytology. Zhu is the first author of the journal. The research was funded by the US Department of Agriculture.

Reference: “Characterization of mooring and in vitro Inhibitory activity of Flavan-3-ols and dimeric proanthocyanidins against the main protease activity of SARS-Cov-2 “by Yue Zhu and De-Yu Xie, November 30, 2020, Frontiers of phytology.
DOI: 10.3389 / fpls.2020.601316