SARS-CoV-2 neutralizing activity of polyphenols in a special green tea extract preparation.

Autor: Kicker E; Diagnostic and Research Center for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; BioTechMed, Mozartgasse 12/II, 8010 Graz, Austria., Tittel G; Phytovisions GmbH & Co. KG, Karwendelstrasse 29, 82467 Garmisch-Partenkirchen, Germany., Schaller T; Dronania pharmaceuticals GmbH, Karl- Benz- Strasse 3, 86825 Bad Woerishofen, Germany., Pferschy-Wenzig EM; Institute of Pharmaceutical Sciences, University of Graz, Beethovenstraße 8, 8010 Graz, Austria; BioTechMed, Mozartgasse 12/II, 8010 Graz, Austria., Zatloukal K; Diagnostic and Research Center for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; BioTechMed, Mozartgasse 12/II, 8010 Graz, Austria., Bauer R; Institute of Pharmaceutical Sciences, University of Graz, Beethovenstraße 8, 8010 Graz, Austria; BioTechMed, Mozartgasse 12/II, 8010 Graz, Austria. Electronic address: rudolf.bauer@uni-graz.at.
Jazyk: angličtina
Zdroj: Phytomedicine : international journal of phytotherapy and phytopharmacology [Phytomedicine] 2022 Apr; Vol. 98, pp. 153970. Date of Electronic Publication: 2022 Jan 30.
DOI: 10.1016/j.phymed.2022.153970
Abstrakt: Background: The COVID-19 pandemic will continue to threaten our health care systems in the next years. In addition to vaccination there is a need for effective tools for prevention and treatment. Products from natural sources, like standardized plant extracts offer a wide range of antiviral effects and possible applications.
Purpose: The aim of this study was to investigate, whether a sorbitol/lecithin-based throat spray containing concentrated green tea extract (sGTE) interacts with SARS-CoV-2 viral particles and additionally is capable to block the virus replication.
Study Design and Methods: The antiviral effect was studied in a VeroE6 cell culture model, including concentration/effect correlations and the biological mechanism of virus blockade, using the Wuhan type of SARS CoV-2 as well as its beta- and delta-mutations. In addition, the qualitative and quantitative tannin profile present on the oral mucosa after spray application has been investigated by LC-MS/MS and HPLC-DAD analyses of (-)-epigallocatechin-3-O-gallate (EGCG) and related catechin derivatives.
Results: The findings of this study demonstrate, that sGTE has strong neutralizing activity on SARS-CoV-2 resulting in an up to 6,3E+04-fold reduction of infectivity independent from the strain. The type of interaction of sGTE with surface proteins seems to be direct and non-specific concerning the viral surface protein structures and resembles the general non-specific activity of polyphenols. By HPLC-DAD analysis, eight catechins were identified in sGTE, with EGCG and (-)-epicatechin-3-O-gallate as the most abundant ones. The total content of catechin derivatives, calculated as catechin, was 76 g/100 g. LC-MS/MS and HPLC-DAD analyses of throat swabs after application of a sGTE spray have shown that the concentrations of green tea tannins in the pharyngeal mucosa are higher than the effective dose found in the in vitro studies with SARS-CoV-2, even 1 h after the last application.
Conclusion: The findings of this study suggest that sGTE has strong neutralizing activity on SARS-CoV-2 independent from the strain (Wuhan strain, beta- or delta-variants). sGTE might be relevant for reduction of corresponding viral infections when periodically applied to mouth and throat.
(Copyright © 2022. Published by Elsevier GmbH.)
Databáze: MEDLINE
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