Researchers from multiple Japanese institutions have made a significant breakthrough in the fight against COVID-19. They have discovered that compounds found in green and black teas have the ability to inactivate the highly transmissible Omicron subvariants of the SARS-CoV-2 virus. This discovery has important implications for preventing the spread of the virus through saliva and could contribute to the development of therapeutic interventions.
The Omicron variant has posed significant challenges in managing the COVID-19 pandemic. With its highly transmissible and mutation-rich spike proteins, the variant has caused breakthrough infections even in vaccinated individuals. It rapidly spread worldwide in 2022, giving rise to sub-lineages characterized by additional mutations.
Understanding that the virus primarily spreads through saliva is crucial in preventing transmission. Infected individuals release the virus into droplets and aerosols when speaking, sneezing, or coughing. Inactivating the virus in saliva is therefore a vital strategy in preventing further spread.
Previous studies had already shown that certain types of tea, such as green tea, roasted green tea, oolong tea, and black tea, could reduce the infectivity of the conventional strain of SARS-CoV-2. Specific compounds in these teas, known as tea catechins, were found to rapidly inactivate the virus by binding to the spike protein’s receptor binding domain.
In a series of meticulous experiments, the researchers exposed the Omicron subvariants to various types of tea. To their surprise, all tested subvariants were effectively inactivated within 10 seconds of exposure to green tea, Matcha green tea, and black tea. This mirrored the team’s previous success with the conventional strain of the virus.
Further investigation into the specific compounds responsible for inactivation revealed that while various tea catechins did not significantly affect the infectivity of the Omicron subvariants, two compounds, EGCG and GCG, demonstrated strong antiviral properties. EGCG inactivated over 99% of certain viruses, while another group of compounds called theaflavins also significantly decreased the virus titers of multiple subvariants.
Molecular docking simulations were then used to better understand the interaction between these tea compounds and the Omicron subvariants. The simulations revealed the crucial roles of specific amino acid substitutions in the Omicron spike protein’s receptor binding domain in determining susceptibility to EGCG and theaflavins. This highlights the potential of these tea compounds as antiviral agents.
Clinical research extended the study’s findings, showing that consuming candies infused with green tea or black tea resulted in saliva samples with the ability to inactivate the virus in vitro. The presence of high concentrations of EGCG and theaflavins in the saliva immediately after consumption linked the consumption of tea-infused products to the presence of potent antiviral compounds in saliva.
Overall, this groundbreaking study conducted by Japanese researchers has uncovered the remarkable potential of tea catechins and their derivatives in inactivating the Omicron subvariants of the SARS-CoV-2 virus. These findings pave the way for potential therapeutic interventions and suggest that tea-infused products could contribute to reducing the virus load in the oral cavity and gastrointestinal tract, potentially curbing transmission. As the world continues to combat the challenges posed by evolving variants, this study offers hope and valuable insights into strategies to prevent future pandemics. The humble tea leaf may prove to be a powerful ally in the battle against COVID-19.