Tea Polyphenols Prevent and Intervene in COVID-19 through Intestinal Microbiota

Abstract

Although all countries have taken corresponding measures, the coronavirus disease 2019 (COVID-19) is still ravaging the world. To consolidate the existing anti-epidemic results and further strengthen the prevention and control measures against the new coronavirus, we are now actively pioneering a novel research idea of regulating the intestinal microbiota through tea polyphenols for reference. Although studies have long revealed the regulatory effect of tea polyphenols on the intestinal microbiota to various gastrointestinal inflammations, little is known about the prevention and intervention of COVID-19. This review summarizes the possible mechanism of the influence of tea polyphenols on COVID-19 mediated by the intestinal microbiota. In this review, the latest studies of tea polyphenols exhibiting their own antibacterial and anti-inflammatory activities and protective effects on the intestinal mucosal barrier are combed through and summarized. Among them, (−)-epigallocatechin-3-gallate (EGCG), one of the main monomers of catechins, may be activated as nuclear factor erythroid 2 p45-related factor 2 (Nrf2). The agent inhibits the expression of ACE2 (a cellular receptor for SARS-CoV-2) and TMPRSS2 to inhibit SARS-CoV-2 infection, inhibiting the life cycle of SARS-CoV-2. Thus, preliminary reasoning and judgments have been made about the possible mechanism of the effect of tea polyphenols on the COVID-19 control and prevention mediated by the microbiota. These results may be of great significance to the future exploration of specialized research in this field.

Causal associations of tea intake with COVID-19 infection and severity

“…Recent modeling studies have shown that various tea components are highly effective in blocking SARS-CoV-2 infection ( 24 , 25 , 47 , 48 ). In addition, tea polyphenols might suppress the virus through their beneficial effects on intestinal microbiota ( 49 ). It has yet to be determined whether habitual tea consumption may exert an effect against COVID-19 in exposed populations.…”

Health Benefits of Tea Polyphenols and Mechanisms via Regulating Gut Microbiota

“…The major bacterial phyla in the intestinal microorganisms comprise actinobacteria, Proteobacteria, Verrucomicrobia, and Fusobacteria [13]. Fundamental processes such as digestion, metabolism, and vitamin production in animal bodies are heavily reliant on the presence and activity of the gut microbiota [14].…”

“…Conversely, a wealth of species is often associated with a "healthy gut" [15]. The gut microbiota has the capability to generate enzymes facilitating the breakdown of polysaccharides and plant polyphenols, as well as the synthesis of certain vitamins, thereby contributing to the intestinal well-being of the host [14]. A state of harmonious equilibrium among bacteria is maintained within a healthy gastrointestinal system, where genetic and environmental factors play a role in determining the type, quantity, and proportion of gut microbiota.…”

Clinical Research Progress of Small Molecule Compounds Targeting Nrf2 for Treating Inflammation-Related Diseases

“…EGCG has entered phase 2/3 clinical trials. According to the strength of oxidation, the order of oxidation of EGCG and its three derivatives ((Epigalloeatechin)EGC, (Epieatechin gallate) ECG, (Epieatechin) EC) is: EGCG > EGC > ECG > EC [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Therefore, it can be speculated that the 3′,4′,5′-trihydroxyl group of the B ring in the EGCG structure is important for its antioxidant capacity.…”