A medical expert is convinced tannin can help in the fight against Covid. He spoke exclusively to Wine-Searcher.
By W. Blake Gray | Posted Monday, 08-Feb-2021
It’s possible that the tannins in red wine, and tea, could inhibit Covid-19. A prominent cancer researcher in Taiwan is investigating the theory right now.
Dr. Mien-Chie Hung is president of China Medical University in Taiwan. He spent 40 years in the US and for many years was chair of the department of molecular and cellular oncology at University of Texas MD Anderson Cancer Center in Houston before moving home to Taiwan in 2019.
His theory is based on Taiwanese research from 2003 into SARS, which like Covid-19 is caused by a coronavirus. SARS appeared in China in 2002 and killed 774 people in 11 countries before disappearing. There has not been a case of SARS reported since 2004, although a team at a different Houston research hospital developed a prototype vaccine in 2016 in the event of a re-emergence. That vaccine has never been tested.
“SARS occurred about a half year, and then totally disappeared,” Hung told Wine-Searcher. “All the research stopped. Nobody wanted to do it anymore. We thought tannin might have some impact on SARS but the research is incomplete.”
Hung said that the Taiwanese lab showed that pure tannic acid can inhibit two enzymes critical to SARS that are also critical to Covid-19.
First, tannic acid was shown to have the ability to inhibit the main protease of SARS, which is also the main protease of Covid-19. Proteases are enzymes that perform necessary biological functions in many organisms; protease inhibitors are how AIDS drugs work.
Second, tannic acid also inhibits an important enzyme in human cells, TMP RSS2. This enzyme is on the surface of human cells. When a human is infected by a coronavirus, the virus recognizes TMP RSS2 on the cell surface and clips it with its spike protein. Several research projects are looking into inhibiting TMP RSS2 and one inhibitor of it has already been approved for clinical use in treating Covid-19.
“Two birds, one stone,” Hung said. “The spike protein’s entry into the human cell has two steps. Tannic acid can inhibit both steps.”
That’s the very good news. Before you start guzzling Malbec, now come the caveats.
First, researchers worked with pure tannic acid. Hung said that tannic acid is only a part of the tannins of wine and it is unknown if all tannins will have the same effect on coronaviruses.
“Tannin is rich in the red wine because it is also rich in grapes,” Hung said. “However, tannic acid is not equivalent to tannin. When we do research it is very difficult to use a mixture. What we use is pure compound, and that is tannic acid. That belongs to the tannin family. Red wine and different fruits, they have tannins in the tannin family.
“Most of the time when people analyze red wine, they analyze tannin. However, at this…
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