Tannin as a therapeutic agent for SARS-CoV-2

In a recent review published in International Journal of Biological SciencesResearchers reviewed tannins as a treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Background

The unprecedented increase in SARS-CoV-2 infection worldwide has ensured the development of new anti-SARS-CoV-2 agents. Researchers have proposed tannin compounds to limit the growth of SARS-CoV-2. However, due to the structural diversity of tannin derivatives, the potential use of tannins in the prevention and management of coronavirus disease 2019 (COVID-19) is not well characterized.

About reviews

In this study, researchers reviewed the potential role of natural tannins in the management of SARS-CoV-2 infection.

Preface

Tannins are polyphenolic compounds derived from the trees, bark, leaves, roots, fruits and seeds of several plants and can be divided into four different categories. Condensed tannins, hydrolyzable tannins, fluorotannins, and complex tannins. Hydrolyzable tannins can be further subdivided into tannic acid (TA) or gallotannin and ellagitannin (eg pomegranate). Condensed tannins include catechins, procyanidins and proanthocyanidins. The most abundant tannins are condensed tannins, followed by hydrolyzable tannins. Fluorotannins are rare and are mainly found in large brown algae.

In general, fruits such as pomegranates, apples, persimmons, grapes, bananas, guava, cashew apples, blackberries, chokeberries and raspberries have high tannin content. Most grape-derived tannins are condensed tannins, with an estimated TA content of grape seeds of 4.1g / 100g. In berries and grapes, 20% and 80% of the tannin compounds are derived from the skin and seeds, respectively, and 60% of the wine tannins are extracted from the grape skin.

Biological properties of tannins

Previous studies have shown that ingestion of red wine containing 200 mg of procyanidins per day improves skin moisturization and whitening in healthy women aged 30-60 years within 12 weeks. In addition, daily supplements at 136 mg and 19.2 mg concentrations of polyphenols and resveratrol isolated from red wine for 8 weeks increase sensitivity to insulin and increase serum triglyceride (TG) and low density lipoprotein (LDL) levels. I lowered it. Diabetes.

Dietary TA supplementation is effective for behavioral and cognitive dysfunction by inhibiting the processing of amyloid precursor protein, reducing β-amyloid deposition in the brain vessels, and reducing neuroinflammation in Alzheimer-like transgenic mouse models. It is a target. TA catechol compounds remove reactive oxygen species (ROS), thereby contributing to TA’s anti-cancer and anti-inflammatory properties.

TA protected rat renal tissue from post-ischemic reperfusion injury due to oxidative stress mediated activation of NRF2 (nuclear factor erythroblast 2 related factor 2). Subcutaneous TA administration reduces fibrosis of myocardial tissue, including TLR4 (Toll-like receptor 4), NF-κB (nuclear factor kappa B), Bcl-2 (B cell lymphoma-2), Bax (Bax), etc. Reduced the level of apoptotic mediators. Bcl-2 related proteins in isoproterenol-induced mice with myocardial fibrosis) and p38 kinase levels (in response to stress).

In addition, TA reduced levels of cytokine molecules such as rat renal injury and tumor necrosis factor-α (TNF-α) and interleukin (IL) -6,8. TA has been reported to enhance chemotherapy-induced apoptosis.Proven tannins from persimmon Effectiveness For viruses such as herpes simplex virus-1 (HSV-1), follicular stomatitis virus (VSV), and influenza virus.

Tannin as an anti-SARS-CoV-2 agent

Oral administration of tannins extracted from chestnuts and kebraco with B12 vitamin supplementation and standard treatment regimens reduced levels of TNF-α and MIP-1α (macrophage inflammatory protein-1α) in individuals hospitalized with COVID-19. ..In addition, TA can strongly inhibit M^Professional/ 3CL^Professional (Major proteases / 3-chymotrypsin-like cysteine ​​proteases, and TMPRSS2 (Transmembrane protease serine 2) This is an essential protein for SARS-CoV-2 growth.Similar activity has been observed by punicaraginin and proanthocyanidins In vitro..

In Syrian hamsters, forced orally administered persimmon-derived tannins suppress SARS-CoV-2 titers, reduce the severity of COVID-19-related pneumonia, and produce inflammation-related genes such as interferon gamma (IFN-γ). Reduced expression. ..Green tea-derived tannins inhibited SARS-CoV-2 replication In vitro It lasts for 1 hour after administration by throat spray to the pharyngeal mucosa.

In addition, hydrolyzable tannins such as castarin and telcaten have been reported to have potential anti-SARS-CoV-2 effects by inhibiting M.^Professional/ 3CL^Professional activity. Orally administered TA isomers have been shown to be effective against SARS-CoV-2 mutants such as Delta and Omicron. However, clinical trials are required to translate the TA isomer as a conventional anti-SARS-CoV-2 treatment.

Conclusion

The studies included in the current review support the management of infections that cause metabolic, immune, and cognitive dysfunction, and the use of tannins for cancer protection through oxidative stress and reduced levels of inflammatory cytokines. In addition, some studies support the use of tannins, especially TA, as safe and effective antiviral agents to combat and overcome COVID-19 and future pandemics.

Natural sources of tannins such as fruits and tea can be utilized to develop effective drugs against existing rapid SARS-CoV-2 variants, daily to protect tannins from SARS-CoV-2. Can be incorporated into your diet. In addition, tannin compounds can be used in combination with drugs approved by the Food and Drug Administration (FDA) to increase efficacy against SARS-CoV-2 and other viruses.