Epigallocatechin-3-gallate (EGCG), a prominent plant-based catechin predominantly derived from Camellia sinensis and widely available on the market as a health supplement, has garnered significant attention for its potential therapeutic benefits, particularly in the context of type 2 diabetes mellitus (T2DM). This review explores the multifaceted role of EGCG in addressing the "ominous octet"-the 8 core pathophysiological defects associated with T2DM. The literature search was carried out using key terms "EGCG" OR "epigallocatechin-3-gallate" OR "epigallocatechin gallate" AND "diabetes" OR "insulin resistance" OR "hyperglycemia" in the PubMed and Scopus databases. The search was constrained to articles published between January 2018 and April 2024, focusing on the document type. Full-text articles published in English and relevant to EGCG that featured a single active ingredient, included clearly explained diabetes relief mechanism, and included ominous octet aspects were included in the final review. The outcomes of the included studies were reviewed and categorized based on 8 core pathophysiological defects, collectively referred to as the ominous octet in T2DM. This review concludes that EGCG is a potent hypoglycemic agent that has beneficial effects against the ominous octet in addition to its pharmacological activities in modulating gut microbiota dysbiosis, carbohydrate digestion and metabolism, glucose transporter-mediated intestinal glucose-uptake, endothelial dysfunction, and renal damage that are significantly associated with pathogenesis of T2DM. This extensive scientific evidence suggests that EGCG may offer a novel approach to traditional antidiabetic therapies, potentially improving glycemic control and mitigating complications associated with T2DM. The inhibitory effects of EGCG on sodium-glucose transport proteins and their role in reducing renal glucose reabsorption remain unexplored, highlighting a significant research gap. Future research should also aim to broaden the scope by investigating the "egregious eleven," which comprise a more comprehensive range of diabetic pathophysiological features. This review underscores the therapeutic promise of EGCG for managing T2DM and encourages ongoing research to fully elucidate its clinical applications. Please cite this article as: Wong CN, Lim YM, Liew KB, Chew YL, Chua AL, Lee SK. A review on mechanistic actions of epigallocatechin-3-gallate in targeting the ominous octet of type 2 diabetes mellitus. J Integr Med. 2025; 23(4): 344-356.
Diabetes Mellitus, Type 2/physiopathology* ; Humans ; Catechin/therapeutic use* ; Hypoglycemic Agents/therapeutic use* ; Animals ; Insulin Resistance

OBJECTIVETo evaluate the efficacy of epigallocatechin gallate (EGCG) in treatment of corneal alkali burn injury in mice.

METHODSCorneal alkali burn injury was induced by sodium hydroxide method in C57BL/6J mice. The mice with cornea burns were treated intraperitoneally with EGCG solution or phosphate buffer solution (PBS) respectively. The healing of corneal epithelium, the formation of corneal neovascularization (CNV) and the inflammation reaction were assessed by slit -lamp microscopy and histological examination. Expression of vascular endothelial growth factor (VEGF) mRNA and protein in cornea was evaluated by real -time reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Myeloperoxidase (MPO) assay was used to quantitatively evaluate the polymorphonuclear neutrophils (PMNs) infiltration in the corneas.

RESULTSThe healing rate of corneal epithelium in EGCG group was significantly higher than that of PBS group at d1, d3 and d7 after treatment (d1: 41.0%±13.0% vs 23.8%±7.6%; d3: 76.6%±7.5% vs 61.2%±6.8%; d7: 87.8%±8.5% vs 74.0%±9.1%; all P <0.05). The CNV scores and the number of CNV in the corneal sections of EGCG group were significantly lower than those of PBS group at d3, d7 and d14 after treatment (CNV score: d3: 1.1±0.5 vs 6.6±1.0; d7: 1.3±0. 3 vs 8.1±1.0; d14: 0.9±0.2 vs 9.2±1.1; CNV number: d3: 1.68±0.61 vs 2.92±0.95; d7: 4.80±1.36 vs 7.92±1.28; d14: 3.64±0.71 vs 5.88±0.76; all P<0.05) . The expression of VEGF protein at d3 (0.19±0.05 vs 0.45±0.08) and d7 (0.42±0.07 vs 0.84±0.09), the expression of VEGF mRNA at d1, d3 and d7 in EGCG group were significantly lower than those in PBS group (all P <0.05). Compared to PBS group, the inflammatory index at d3 (3.2±0.4 vs 3.7±0.5) and d7 (2.3±0.5 vs 4.0±0.0), the number of PMNs in the corneal sections and the MPO values at d3, d7 and d14 in EGCG group were significantly decreased (PMNs: d3: 34.5±15.7 vs 90.0±28.8; d7: 17.1±11.4 vs 54.9±25.9; d14: 12. 8±4.6 vs 39.0±17.9; all P <0.05).

CONCLUSIONIn the murine corneal alkali burn model, intraperitoneal injection of EGCG solution can promote the healing of corneal epithelium, inhibit the formation of CNV and reduce the inflammatory cell infiltration in the corneas.

Alkalies ; Animals ; Burns, Chemical ; drug therapy ; Catechin ; analogs & derivatives ; therapeutic use ; Cornea ; drug effects ; pathology ; Corneal Neovascularization ; prevention & control ; Disease Models, Animal ; Eye Burns ; drug therapy ; Inflammation ; drug therapy ; immunology ; Mice ; Mice, Inbred C57BL ; Neutrophils ; cytology ; RNA, Messenger ; Vascular Endothelial Growth Factor A ; metabolism

AIM: Microvasculature and microenvironment play important roles in proliferation, invasion, metastasis and prognosis in non-small cell lung cancer (NSCLC), which might be altered by many anti-angiogenic drugs. Epigallocatechin-3-gallate (EGCG), a natural anti-angiogenesis agent refined from green tea, was defined to have multiple effects on angiogenesis factors, such as endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and angiopoietins (ANGs). Hypothesizing that EGCG might regulate microvasculature and microenvironment in NSCLC, the effects of EGCG on microvessel density (MVD), expression of Ang-1 and Ang-2, interstitial fluid pressure (IFP), tumor hypoxia, and chemotherapy sensitivity were examined. METHODS AND RESULTS: EGCG treatment of A549 cells in mice bearing xenografts in vivo led to a significant decrease of MVD detected by CD31, and of Ang-2 expression detected by quantum dots double-label immunofluorescence assessment, while Ang-1 decreased with no significance. Decreased IFP was measured by the Wink-in-needle method, while hypoxia was assessed by polarographic electrode and pimonidazole (PIMO) immunohistochemistry. Assuming that these changes would increase response to chemotherapy, tumor growth studies were p[erformed in nude mice with xenografts, which were then treated with EGCG and the chemotherapeutic agent cisplatin. EGCG therapy combined with cisplatin led to synergistic inhibition of tumor growth, compared with administration of each treatment separately (P < 0.001). According to linear regression analysis, IFP was positively correlated with PIMO staining (R(2) = 0.618, P = 0.002), Ang-2 was correlated with MVD (R(2) = 0.423, P = 0.022), IFP (R(2) = 0.663, P = 0.01) and PIMO staining (R(2) = 0.694, P = 0.01). CONCLUSION IFP and delivery of oxygen might be improved by rebalance of Ang-1/Ang-2 under the treatment of EGCG in NSCLC, which also acts as a sensitizer of chemotherapy. These studies established a new mechanism for using EGCG as an adjuvant chemotherapy agent through modifying microvasculature and microenvironment.
Angiogenesis Inhibitors ; administration & dosage ; Angiopoietin-1 ; genetics ; metabolism ; Angiopoietin-2 ; genetics ; metabolism ; Animals ; Antineoplastic Agents ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; Catechin ; administration & dosage ; analogs & derivatives ; Chemotherapy, Adjuvant ; Cisplatin ; therapeutic use ; Drug Therapy, Combination ; Extracellular Fluid ; drug effects ; metabolism ; Female ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Oxygen ; metabolism

Heat shock protein 90 is a new target of antitumor drug, the inhibitor of Hsp90 fight against tumor by destroy and degrade the structure of protein. In recent years, looking for Hsp90 inhibitor is not only via structure modifying of natural products, but also via high throughput screening and computer aided drug design to find and synthesize new kinds of Hsp90 inhibitor. Anyway, Hsp90 inhibitor has considered as an important biology target and to pay more and more attention. This review describes recent developments of small molecule Hsp90 inhibitors.
Adenine ; analogs & derivatives ; chemistry ; pharmacology ; Animals ; Anisoles ; chemistry ; pharmacology ; Antineoplastic Agents ; chemistry ; pharmacology ; therapeutic use ; Benzoquinones ; chemistry ; therapeutic use ; Catechin ; analogs & derivatives ; chemistry ; pharmacology ; Cell Line, Tumor ; Crystallization ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; chemistry ; Heterocyclic Compounds, 2-Ring ; chemistry ; pharmacology ; Humans ; Lactams, Macrocyclic ; chemistry ; therapeutic use ; Macrolides ; chemistry ; pharmacology ; Molecular Structure ; Neoplasms ; drug therapy ; pathology ; Pyrazoles ; chemistry ; pharmacology ; Structure-Activity Relationship

BACKGROUNDGreen tea is an important source of flavonoids in human diets and epidemiological data correlate green tea consumption with a reduced cancer risk. Given its complicated properties at effective concentrations, we put epigallocatechin-3-gallate (EGCG) that previously reported on its anti-proliferative activities against several cancer cell lines on our research agenda to further examine the mechanism of its chemopreventive potential.

METHODSRNA interference (RNAi) expression vector pSilencer 3.1-H1 was used to construct recombinant nuclear factor erythroid 2 related factor 2 (Nrf2)-targeting RNAi plasmids. EGCG (5 microg/ml) was added into the culture fluid of cells before and after transfection. RT-PCR and Western blotting were used to detect the expression of uridine 5'-diphosphate-glucuronosyltransferase (UGT) 1A in cells. Forty male BALB/c mice were assigned to four groups: a normal unexposed control and three groups treated with varying doses of EGCG. Four weeks later, the mice were sacrificed, and their colon tissues were subjected to mRNA and protein expression of Nrf2 and UGT1A via RT-PCR and Western blotting analysis.

RESULTSEGCG up-regulated the expression of Nrf2 and increased the level of UGT1A in cells. The blockade of Nrf2 activity via RNA intervention largely attenuated the induction of UGT1A expression by EGCG. In mice, the mRNA and protein levels of Nrf2 and UGT1A detected by RT-PCR and Western blotting increased (both P < 0.05 compared with the control). This increase in Nrf2 expression also had a positive correlation with an increased UGT1A expression.

CONCLUSIONSEGCG mediated its effect in part by inducing the NRF2 signaling pathway and increasing UGT1A expression. Both in vitro and in vivo studies demonstrated the role of NRF2 and UGT1A expression in the potential use of EGCG as a possible chemopreventive agent and supported further study of EGCG for cancer treatment.

Animals ; Anticarcinogenic Agents ; pharmacology ; therapeutic use ; Blotting, Western ; Caco-2 Cells ; Catechin ; analogs & derivatives ; pharmacology ; therapeutic use ; Colonic Neoplasms ; drug therapy ; metabolism ; Gene Expression Regulation ; Gene Expression Regulation, Neoplastic ; Glucuronosyltransferase ; genetics ; metabolism ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; NF-E2-Related Factor 2 ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo determine the anti-obesity effects of oolong tea on diet-induced overweight or obesity.

METHODSA total of 8 g of oolong tea a day for 6 weeks was ingested by 102 diet-induced overweight or obese subjects. The body fat level of the subjects was determined at the same time by taking body weight, height and waist measurements. The thickness of the subcutaneous fat layer was also determined on the abdomen 3 cm to the right of the navel by the ultrasonic echo method. On the other hand, effects of oolong tea ingestion on plasma triglyceride (TG) and total cholesterol (TC) were determined. Inhibitions of pancreatic lipase by oolong tea extract and catechins in vitro were also determined.

RESULTSA total of 70% of the severely obese subjects did show a decrease of more than 1 kg in body weight, including 22% who lost more than 3 kg. Similarly, 64% of the obese subjects and 66% of the overweight subjects lost more than 1 kg during the experiment, and the subcutaneous fat content decreased in 12% of the subjects. The correlation between weight loss and subcutaneous fat decrease in men (r=0.055) was obviously lower than that in women (r=0.440, P<0.01). Body weight loss was signifificantly related to the decrease of the waist size in men (r=0.730, P<0.01) and women (r=0.480, P<0.01). Also, the correlation between subcutaneous fat reduction and decreased waist size was signifificant in women (r=0.554, P<0.01), but not in men (r=0.050, P>0.05). Moreover, the plasma levels of TG and TC of the subjects with hyperlipidemia were remarkably decreased after ingesting oolong tea for 6 weeks. In vitro assays for the inhibition of pancreatic lipase by oolong tea extract and catechins suggest that the mechanism for oolong tea to prevent hyperlipidemia may be related to the regulative action of oolong tea catechins in lipoprotein activity.

CONCLUSIONSOolong tea could decrease body fat content and reduce body weight through improving lipid metabolism. Chronic consumption of oolong tea may prevent against obesity.

Adult ; Aged ; Animals ; Beverages ; Body Height ; drug effects ; Body Weight ; drug effects ; Catechin ; pharmacology ; Cholesterol ; blood ; Diet ; Feeding Behavior ; drug effects ; Female ; Humans ; Lipase ; antagonists & inhibitors ; Male ; Middle Aged ; Obesity ; blood ; drug therapy ; Overweight ; blood ; drug therapy ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Subcutaneous Fat ; drug effects ; Sus scrofa ; Tea ; metabolism ; Triglycerides ; blood ; Young Adult