RALEIGH, N.C. — A new study from a professor of plant biology at N.C. State University has found that chemical compounds in green tea and certain other plants can potentially slow the replication of SARS-Cov-2, the coronavirus that causes COVID-19.
The findings, published in the peer-reviewed scientific journal Frontiers in Plant Science, show that chemical compounds, like flavonoids, are able to bind to enzymes in SARS-Cov-2 that help viruses grow.
Flavonoids, which have been shown to have antiviral properties, are present in a wide variety of plants and fruits. De-Yu Xie, professor of plant and microbial biology at NC State, has studied them for years.
A native of China, Xie began to think about the effects of flavonoids when the first outbreaks were reported in Wuhan. But it wasn't until March, when the virus began to significantly spread across the U.S., that his study started in earnest, Xie told The News & Observer.
It's often hard to get money for these types of studies, Xie said, but his lab was able to get funding from the U.S. Department of Agriculture, according to N.C. State.
Xie published the research along with Yue Zhu, a post-doctoral student in his lab, and most of the work was done during the summer.
He conducted his research using computer simulations and lab tests. The tests found that compounds in green tea, two varieties of muscadine grapes and dark chocolate were the most effective at inhibiting the virus by blocking its main protease enzyme.
In the computer simulations as well as the lab tests, the flavonoid compounds are able to fill a portion of the virus' main protease that are like "pockets."
"When this pocket was filled, the protease lost its important function" like replication, Xie said.
This was especially true for the flavonoids found in green tea and muscadine, he said. The compounds in cocoa powder and dark chocolate also were effective but less so.
"Green tea has five tested chemical compounds that bind to different sites in the pocket (of the main protease), essentially overwhelming it to inhibit its function," Xie said. "Muscadine grapes (also) contain these inhibitory chemicals in their skins and seeds."
"Plants use these compounds to protect themselves," he added, "so it is not surprising that plant leaves and skins contain these beneficial compounds."
However, more research needs to be done on the compounds. Xie's lab, for instance, has not yet conducted human tests.
Xie added in an email that plants with these chemical compounds are still no substitute for vaccines and other therapeutics.
But he hopes that publishing his findings will help him find partners and funding to expand the research into human trials.
"What I really hope that my paper can convince doctors or clinical trial scientists that we can collaborate," Xie said.
In the meantime, Xie continues to drink green tea every day and recommends it to all of his friends and students.
He now signs off every email he sends with the phrase: "Stay with green tea for safety!"
