Preventive effect of flavor/fragrance components on SARS-CoV-2 infections

The SARS-CoV-2 infection has spread to various areas of the world, and the number of infected people, seriously ill people, and deaths have increased in 2020∼2023. It is important to suppress the spread of virus from infected people to non-infected people in order to prevent the disease from becoming more severe. To protect widespread of virus, flavor/fragrances composition was selected as a convenient effective material to protect the inhibition. It was previously investigated whether flavor/fragrances composition inhibit the binding between the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and host angiotensin converting enzyme 2 (ACE2) in the infection model assay. This binding lead to natural infection of SARS-CoV-2 to tissues. In a previous report, it was found that some Flavor/fragrances compositions strongly inhibited the binding between RBD and ACE2. To clarify whether these flavor/fragrances compositions actually inhibit the infection of SARS-CoV-2, the inhibition assay of infection to VeroE6/TMPRSS2 cells, the inhibition model in vitro, were performed by the treatment of these compositions. Some flavor/fragrances compositions excepting for cinnamyl alcohol, 0.25 %, strongly inhibited the infection of SARS-CoV-2 to VeroE6/TMPRSS2 cells because cinnamyl alcohol could not be completely melted by PBS (pH 7.4) containing 1.5 % Tween 20 and 0.5 % BSA. Among fragrance compounds, cinnamon flavor and cinnamon mint had stronger inhibition effects on the infection effects on SARS-C0V-2 than others. The strategy of using flavor/fragrances compositions such as cinnamon flavor and cinnamon mint may be useful to protect widespread of SARS-CoV-2 in their daily lives.