Milk casein prevents inactivation effect of black tea galloylated theaflavins on SARS-CoV-2 in vitro
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Abstract
Repeated emergence of highly contagious and potentially immune-evading variant SARS-CoV-2 is posing global health and socioeconomical threats. For suppression of the spread of the virus infection among people, a procedure to inactivate virus in saliva may be useful, because saliva of infected persons is the major origin of droplets and aerosols that mediate viral transmission to nearby persons. We previously reported that SARS-CoV-2 is rapidly and remarkably inactivated by treatment in vitro with tea including green tea, roasted green tea, oolong tea and black tea. Tea catechin-derived compounds including theaflavins (TFs) with (a) galloyl moiety(ies) showed this activity. Although black tea is popularly consumed worldwide, a lot of people consume it with sugar, milk, lemon juice, and so on. But it has not been determined whether these ingredients may influence the inactivation effect of black tea against SARS-CoV-2. Moreover, it has not been revealed whether black tea is capable of inactivating variant viruses such as delta variant. Here we examined the effect of black tea on some variants in the presence or absence of sugar, milk, and lemon juice in vitro . Black tea and galloylated TFs remarkably inactivated alpha, gamma, delta and kappa variants. Intriguingly, an addition of milk but not sugar and lemon juice totally prevented black tea from inactivating alpha and delta variant viruses. The suppressive effect was also exerted by milk casein. These results suggest the possibility that intake of black tea without milk by infected persons may result in inactivation of the virus in saliva and attenuation of spread of SARS-CoV-2 to nearby persons through droplets. Clinical studies are required to investigate this possibility.
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SciScore for 10.1101/2021.09.27.461930: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics not detected. Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Chilled on ice, 100 μL of each sample was added to the VeroE6/TMPRSS2 cells and TCID50 assay was performed as above. 4.7. VeroE6/TMPRSS2suggested: JCRB Cat# JCRB1819, RRID:CVCL_YQ49)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not …SciScore for 10.1101/2021.09.27.461930: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics not detected. Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Chilled on ice, 100 μL of each sample was added to the VeroE6/TMPRSS2 cells and TCID50 assay was performed as above. 4.7. VeroE6/TMPRSS2suggested: JCRB Cat# JCRB1819, RRID:CVCL_YQ49)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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