The counteracting effects of (-)-Epigallocatechin-3-Gallate on the immobilization stress-induced adverse reactions in rat pancreas

Comparative Analysis of Epigallocatechin-3-Gallate and TNF-Alpha Inhibitors in Mitigating Cisplatin-Induced Pancreatic Damage Through Oxidative Stress and Apoptosis Pathways

Oxidative stress and inflammation caused by cisplatin, which is frequently used in the treatment of many cancers, damage healthy tissues as well as cancer cells. In this study, we aimed to investigate the effect of epigallocatechin-3-gallate (EGCG) and infliximab (INF) administration on pancreatic endocrine cells in rats treated with systemic cisplatin (CDDP). The rats were randomly divided into 6 groups: group 1 (control group), group 2 (EGCG group), group 3 (CDDP group), group 4 (EGCG + CDDP group), group 5 (CDDP + INF group), and group 6 (EGCG + CDDP + INF group). The study's findings demonstrated that EGCG and INF effectively reduced the cellular damage induced by CDDP in histopathologic investigations of the pancreas. EGCG and INF, whether used individually or in combination, demonstrated a significant reduction in malondialdehyde (MDA) levels and an increase in glutathione (GSH) levels in the rat pancreas compared to the CDDP group. Immunohistochemically, the enhanced presence of insulin and glucagon positivity in the EGCG and INF groups, along with the absence of TUNEL immunopositivity, indicate that both treatments reduced CDDP-induced apoptosis. Furthermore, the observed lack of immunopositivity in TNF-α and 8-OHdG in the groups treated with EGCG and INF, compared to those treated with CDDP, indicates that these substances can inhibit inflammation. EGCG and INF, whether provided alone or together, can potentially reduce the damage caused to pancreatic islet cells by cisplatin. This effect is achieved through their anti-inflammatory and antioxidant properties during the early stages of the condition.

Epigallocatechin gallate: Phytochemistry, bioavailability, utilization challenges, and strategies

Epigallocatechin gallate (EGCG), a green tea catechin, has gained the attention of current study due to its excellent health-promoting effects. It possesses anti-obesity, antimicrobial, anticancer, anti-inflammatory activities, and is under extensive investigation in functional foods for improvement. It is susceptible to lower stability, lesser bioavailability, and lower absorption rate due to various environmental, processing, formulations, and gastrointestinal conditions of the human body. Therefore, it is the foremost concern for the researchers to enhance its bioactivity and make it the most suitable therapeutic compound for its clinical applications. In the current review, factors affecting the bioavailability of EGCG and the possible strategies to overcome these issues are reviewed and discussed. This review summarizes structural modifications and delivery through nanoparticle-based approaches including nano-emulsions, encapsulations, and silica-based nanoparticles for effective use of EGCG in functional foods. Moreover, recent advances to enhance EGCG therapeutic efficacy by specifically targeting its molecules to increase its bioavailability and stability are also described. PRACTICAL APPLICATIONS: The main green tea constituent EGCG possesses several health-promoting effects making EGCG a potential therapeutic compound to cure ailments. However, its low stability and bioavailability render its uses in many disorders. Synthesizing EGCG prodrugs by structural modifications helps against its low bioavailability and stability by overcoming premature degradation and lower absorption rate. This review paper summarizes various strategies that benefit EGCG under different physiological conditions. The esterification, nanoparticle approaches, silica-based EGCG-NPs, and EGCG formulations serve as ideal EGCG modification strategies to deliver superior concentrations with lesser toxicity for its efficient penetration and absorption across cells both in vitro and in vivo. As a result of EGCG modifications, its bioactivities would be highly improved at lower doses. The protected or modified EGCG molecule would have enhanced potential effects and stability that would contribute to the clinical applications and expand its use in various food and cosmetic industries.

Epigallocatechin-3-gallate alleviates type 2 diabetes mellitus via β-cell function improvement and insulin resistance reduction

OBJECTIVES

Epigallocatechin-3-gallate (EGCG) has a good therapeutic effect on type 2 diabetes mellitus (T2DM). This work was designed to explore EGCG's effectiveness in insulin resistance (IR) and pancreas islet β-cell function in a rat model of T2DM.

MATERIALS AND METHODS

Eight-week-old male Sprague Dawley rats were randomly divided into 6 groups, including the Control (normal diet), Diabetes (high-sucrose high-fat [HSHF] diet combined with tail vein injection of streptozotocin [STZ] for T2DM induction) and Treatment Diabetic rats which were treated with metformin [500 mg/kg/d] or EGCG [25, 50 or 100 mg/kg/d] intragastric administration for 10 weeks. With the exception of control animals, the other groups were fed the HSHF diet. EGCG's effects on IR and insulin secretion were assessed by measuring body weights, and fasting blood glucose (FBG), postprandial blood glucose (PBG) and insulin levels. The morphological and molecular changes of pancreas islet β-cells were examined by hematoxylin-eosin (H&E) staining, transmission electron microscopy (TEM) and immunofluorescence.

RESULTS

Rats fed the HSHF diet combined with STZ treatment had increased body weights and blood glucose amounts, accompanied by IR and impaired β-cell function, induced T2DM, and EGCG dose-dependently restored the above indicators. Additionally, EGCG upregulated the pancreatic transcription factors pancreatic duodenal homeobox protein-1 (PDX-1) and musculoaponeurotic fibrosarcoma oncogene homolog A (MafA).

CONCLUSION

These results suggest that EGCG reduces blood glucose amounts, and improve IR and islet β-cell disorder in T2DM.

Epigallocatechin gallate enhances human lens epithelial cell survival after UVB irradiation via the mitochondrial signaling pathway

The aim of the present study was to explore the mechanism underlying the ultraviolet B (UVB) irradiation-induced apoptosis of human lens epithelial cells (HLECs), and to investigate the protective effect of epigallocatechin gallate (EGCG) against the UVB-induced apoptosis of HLECs. HLECs were exposed to different concentrations of EGCG plus UVB (30 mJ/cm²). Cell viability was determined using the MTT assay. Furthermore, mitochondrial membrane potential (Δψm) and apoptosis were assessed by flow cytometry with JC-1 and Annexin V/PI staining, respectively. Moreover, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the levels of GSH, hydrogen peroxide (H₂O₂) and hydroxyl free radicals were determined using biochemical assay techniques. Reverse transcription-quantitative PCR and western blotting were used to detect the mRNA and protein expression levels of Bcl-2, Bax, cytochrome c, caspase-9 and caspase-3, respectively. The results revealed that UVB irradiation reduced the Δψm of HLECs and induced apoptosis. Notably, EGCG significantly attenuated the generation of H₂O₂ and hydroxyl free radicals caused by UVB irradiation in HLECs, and significantly increased CAT, SOD and GSH-Px activities, however, the GSH levels were not significantly increased. EGCG also reduced UVB-stimulated Bax, cytochrome c, caspase-9 and caspase-3 expression, and elevated Bcl-2 expression, suggesting that EGCG may possess free radical-scavenging properties, thus increasing cell viability. In conclusion, EGCG may be able to protect against UVB-induced HLECs apoptosis through the mitochondria-mediated apoptotic signaling pathway, indicating its potential application in clinical practice.