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bioRxiv · 10.1101/2020.12.28.424533

Rapid inactivation in vitro of SARS-CoV-2 in saliva by black tea and green tea

Ohgitani, E.·Shin-Ya, M.·Ichitani, M.·Kobayashi, M.·Takihara, T.·Kawamoto, M.·Kinugasa, H.·Mazda, O.
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Abstract

Saliva plays major roles in human-to-human transmission of the SARS-CoV-2. Recently we reported that black, green and oolong tea significantly inactivated SARS-CoV-2 within 1 min. Theaflavin-3,3-di-gallate (TFDG), theasinensin A (TSA) and (-) epigallocatechin gallate (EGCG) were involved in the anti-viral activities. Here we examined how long period is required for the compounds to inactivate the virus. We also assessed whether tea inactivates SARS-CoV-2 diluted in human saliva. Treatment of SARS-CoV-2 with 500 M TFDG or TSA for 10 sec reduced the virus titer to undetectable levels (less than 1/1,000). Black and green tea decreased virus titer to less than 1/100 within 10 sec even in saliva. These findings suggest a possibility that intake of, or gargling with, tea may inactivate SARS-CoV-2 in saliva in infected individuals, which may eventually attenuate spread of COVID-19 within a population, although clinical studies are required to test this hypothesis by determining the intensity and duration of the anti-viral effect of tea in saliva in humans.

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Ohgitani, E., Shin-Ya, M., Ichitani, M., Kobayashi, M., Takihara, T., Kawamoto, M., Kinugasa, H., Mazda, O.. 2020-12-28. Rapid inactivation in vitro of SARS-CoV-2 in saliva by black tea and green tea. https://doi.org/10.1101/2020.12.28.424533

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