Potential protective mechanisms of green tea polyphenol EGCG against COVID-19

Abstract

Background The world is in the midst of the COVID-19 pandemic. In this comprehensive review, we discuss the potential protective effects of (−)-epigallocatechin-3-gallate (EGCG), a major constituent of green tea, against COVID-19. Scope and approach Information from literature of clinical symptoms and molecular pathology of COVID-19 as well as relevant publications in which EGCG shows potential protective activities against COVID-19 is integrated and evaluated. Key findings and conclusions EGCG, via activating Nrf2, can suppress ACE2 (a cellular receptor for SARS-CoV-2) and TMPRSS2, which mediate cell entry of the virus. Through inhibition of SARS-CoV-2 main protease, EGCG may inhibit viral reproduction. EGCG via its broad antioxidant activity may protect against SARS-CoV-2 evoked mitochondrial ROS (which promote SARS-CoV-2 replication) and against ROS burst inflicted by neutrophil extracellular traps. By suppressing ER-resident GRP78 activity and expression, EGCG can potentially inhibit SARS-CoV-2 life cycle. EGCG also shows protective effects against 1) cytokine storm-associated acute lung injury/acute respiratory distress syndrome, 2) thrombosis via suppressing tissue factors and activating platelets, 3) sepsis by inactivating redox-sensitive HMGB1, and 4) lung fibrosis through augmenting Nrf2 and suppressing NF-κB. These activities remain to be further substantiated in animals and humans. The possible concerted actions of EGCG suggest the importance of further studies on the prevention and treatment of COVID-19 in humans. These results also call for epidemiological studies on potential preventive effects of green tea drinking on COVID-19.

Antiviral and Immunomodulatory Effects of Pelargonium sidoides DC. Root Extract EPs® 7630 in SARS-CoV-2-Infected Human Lung Cells

“…The broad spectrum of polyphenols such as tannins ( Mehany et al, 2021 ; Umeoguaju et al, 2021 ) and catechins e.g., from green tea ( Chourasia et al, 2021 ; Zhang et al, 2021 ) strongly interact with viral envelope proteins and were found to exhibit antiviral activity. To assess the antiviral potential of polyphenol-containing EPs 7630, we infected human lung cells with highly pathogenic human coronaviruses in the presence of EPs 7630.…”

“…is efficacious as a treatment for acute bronchitis ( Matthys et al, 2003 ; Chuchalin et al, 2005 ; Matthys and Funk, 2008 ; Kamin et al, 2010a ; Kamin et al, 2010b ; Matthys et al, 2010 ; Kamin et al, 2012 ), sinusitis ( Bachert et al, 2009 ), common cold ( Lizogub et al, 2007 ; Riley et al, 2018 ; Riley et al, 2019 ), and acute non-GABHS tonsillopharyngitis ( Bereznoy et al, 2003 ). Similar to other proanthocyanidin-containing substances such as green tea ( Chourasia et al, 2021 ; Zhang et al, 2021 ), in vitro data suggest that EPs 7630 has broad-spectrum antiviral and antibacterial activity as well as immunomodulatory effects, although the precise mechanism of action has not been identified ( Moyo and Van Staden, 2014 ). Distinct antiviral effects of EPs 7630 have been observed in concentrations up to 100 μg/ml, with activity reported mainly against enveloped viruses such as influenza A virus (IAV; e.g.…”

Discovery of Camellia sinensis catechins as SARS-CoV-2 3CL protease inhibitors through molecular docking, intra and extra cellular assays

“…Although the major tea catechin EGCG showed weaker 3CLpro inhibition, it was reported to inhibit SARs-CoV-2 infections through different mechanisms ( Henss et al, 2021 ; Zhang et al, 2021 ). Severe SARs-CoV-2 infection and high mortality are mainly caused by cytokine storm and inflammation, triggering a huge burden of oxidative imbalance on the immune system ( El‐Missiry et al, 2020 ; Zhang et al, 2021 ).…”

Targeting phytoprotection in the COVID-19-induced lung damage and associated systemic effects—the evidence-based 3PM proposition to mitigate individual risks

“…The catechin (−)-epigallocatechin-3-gallate (EGCG), the main flavonoid compound of green tea, has recently been documented in a comprehensive review article that demonstrated its potential protective effect against SARS-CoV-2 infection via multiple mechanisms of action that target viral or host cell proteins evaluated in various preclinical experiments. The protective effects of EGCG are related to preventing cytokine storm-associated acute lung injury/acute respiratory distress syndrome, thrombosis by inhibiting tissue factors and activating platelets, sepsis by inactivating redox-sensitive high mobility group box 1 (HMGB1), and lung fibrosis via increasing Nrf2 and hindering NF-κB activation [ 136 ].…”

“…15 COPD patients [188] Chronic inflammation (asthma) 9,709 individuals [189] Asthma in the elderly as risk factor; plant phenolics against asthma nd chronic inflammation Inflammation, allergies, immunity [13,190,191] Metabolic ill patients with obesity 28 individuals with metabolic syndrome [192] Inflammation in obese individuals Metabolic inflammation and oxidative stress (obesity), [43,193,194] Vascular function 19 essential untreated hypertensive patients [195] Cardiovascular functions, protection against cardiovascular damage Cardiovascular protection, inflammation, anti-thrombotic effects [136,151,152,196,197] Prostate cancer 73 prostate cancer patients [198][199][200] Modulation of cancer patients immune responses, protection against poor outcome Modulation of immunity, inflammation, prevention [19,113,201,202] In vitro (prostate cancer cell lines)…”