EGCG inhibits Cd(2+)-induced apoptosis through scavenging ROS rather than chelating Cd(2+) in HL-7702 cells

The physiological levels of epigallocatechin gallate (EGCG) enhance the Cd-induced oxidative stress and apoptosis in CHO-K1 cells

Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a significant threat to human health and life. It is therefore important to find an effective way of protecting organisms from their adverse effects. One potential product showing a protective effect is green tea. It has been shown that EGCG, which is found in large amounts in green tea, has strong antioxidant properties and can therefore protect cells from the adverse effects of heavy metals. Therefore, the aim of the study was to investigate the effect of EGCG on cells exposed to Cd. In the study, CHO-K1 cells (Chinese hamster ovary cell line) were treated for 24 h with Cd (5 and 10 µM) and EGCG (0.5 and 1 µM) together or separately. Cell viability, ATP content, total ROS activity, mitochondrial membrane potential and apoptosis potential were determined. The results showed that, in tested concentrations, EGCG enhanced the negative effect of Cd. Further analyses are needed to determine the exact mechanism of action of EGCG due to the small number of publications on the subject and the differences in the results obtained in the research.

Defining the mechanisms behind the hepatoprotective properties of curcumin

As a critical cause of human dysfunctionality, hepatic failure leads to approximately two million deaths per year and is on the rise. Considering multiple inflammatory, oxidative, and apoptotic mechanisms behind hepatotoxicity, it urges the need for finding novel multi-targeting agents. Curcumin is a phenolic compound with anti-inflammatory, antioxidant, and anti-apoptotic roles. Curcumin possesses auspicious health benefits and protects against several diseases with exceptional safety and tolerability. This review focused on the hepatoprotective mechanisms of curcumin. The need to develop novel delivery systems of curcumin (e.g., nanoparticles, self-micro emulsifying, lipid-based colloids, solid lipid nanoparticles, cyclodextrin inclusion, phospholipid complexes, and nanoemulsions) is also considered.

The effect of EGCG/tyrosol-loaded chitosan/lecithin nanoparticles on hyperglycemia and hepatic function in streptozotocin-induced diabetic mice

We aimed to study the potential of epigallocatechin-3-gallate/tyrosol-loaded chitosan/lecithin nanoparticles (EGCG/tyrosol-loaded C/L NPs) in streptozotocin-induced type 2 diabetes mellitus (T2DM) mice. The EGCG/tyrosol-loaded C/L NPs were created using the self-assembly method. Dynamic light scattering, Field Emission Scanning Electron Microscopy, and Fourier transform infrared spectroscopy were utilized to characterize the nanoparticle. Furthermore, in streptozotocin-induced T2DM mice, treatment with EGCG/tyrosol-loaded C/L NPs on fasting blood sugar levels, the expression of PCK1 and G6Pase, and IL-1β in the liver, liver glutathione content, nanoparticle toxicity on liver cells, and liver reactive oxygen species were measured. Our findings showed that EGCG/tyrosol-loaded C/L NPs had a uniform size distribution, and encapsulation efficiencies of 84 % and 89.1 % for tyrosol and EGCG, respectively. The nanoparticles inhibited PANC-1 cells without affecting normal HFF cells. Furthermore, EGCG/tyrosol-loaded C/L NP treatment reduced fasting blood sugar levels, elevated hepatic glutathione levels, enhanced liver cell viability, and decreased reactive oxygen species levels in diabetic mice. The expression of gluconeogenesis-related genes (PCK1 and G6 Pase) and the inflammatory gene IL-1β was downregulated by EGCG/tyrosol-loaded C/L NPs. In conclusion, the EGCG/tyrosol-loaded C/L NPs reduced hyperglycemia, oxidative stress, and inflammation in diabetic mice. These findings suggest that EGCG/tyrosol-loaded C/L NPs could be a promising therapeutic option for type 2 diabetes management.

Phytochemicals Involved in Mitigating Silent Toxicity Induced by Heavy Metals

Heavy metals (HMs) are natural elements present in the Earth's crust, characterised by a high atomic mass and a density more than five times higher than water. Despite their origin from natural sources, extensive usage and processing of raw materials and their presence as silent poisons in our daily products and diets have drastically altered their biochemical balance, making them a threat to the environment and human health. Particularly, the food chain polluted with toxic metals represents a crucial route of human exposure. Therefore, the impact of HMs on human health has become a matter of concern because of the severe chronic effects induced by their excessive levels in the human body. Chelation therapy is an approved valid treatment for HM poisoning; however, despite the efficacy demonstrated by chelating agents, various dramatic side effects may occur. Numerous data demonstrate that dietary components and phytoantioxidants play a significant role in preventing or reducing the damage induced by HMs. This review summarises the role of various phytochemicals, plant and herbal extracts or probiotics in promoting human health by mitigating the toxic effects of different HMs.

Epigallocatechin-3-Gallate Reduces Cd-Induced Developmental Toxicity of Bodysize in Caenorhabditis elegans via the PEK-1/eIF-2α/ATF-4 Pathway

Cadmium (Cd), a harmful heavy metal that has no biological purpose, can harm healthy fetal and child development. Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in tea, has been shown to increase cell viability under Cd exposure and ameliorate Cd-induced kidney injury in adult male rats. Using the Caenorhabditis elegans (C. elegans) model, we demonstrated that EGCG mitigated Cd-induced body size developmental toxicity through a mechanism that did not involve chelation with EGCG and was not associated with Cd accumulation and efflux. Our research indicated that the beneficial effects of EGCG on Cd-induced body size developmental toxicity were associated with the mitigation of endoplasmic reticulum stress. Furthermore, our observations indicate that EGCG reduced Cd-induced developmental toxicity in C. elegans via the PEK-1/eIF-2α/ATF-4 pathway. Our results provide important evidence for the potential benefits of consuming tea as a detoxification agent.

Anti-inflammatory Effect of (-)-Epigallocatechin-3-O-gallate on Human Umbilical Vein Endothelial Cells Grown on 316L Stainless Steel via STAT3/NF-κB Signaling

Stainless steel (316L SS) is commonly used to build coronary artery stents for the treatment of occluded arteries. However, tissues in contact with the stent may develop inflammation that can lead to restenosis. The natural substances derived from normal diet provide a pool of candidates that have potential to treat cardiovascular diseases. (-)-Epigallocatechin-3- O-gallate (EGCG), a polyphenolic flavonoid present in green tea, has antioxidant, antithrombogenic, and anti-inflammatory effects, and may reduce the risk of cardiovascular diseases. This study aimed to investigate whether EGCG has an anti-inflammatory effect on human umbilical vein endothelial cells (HUVECs) attached to the surface of 316L SS. We evaluated cell proliferation using the dimethyl thiazolyl tetrazolium bromide method in HUVECs after treatment with EGCG. Enzyme-linked immunosorbent assay (ELISA) assessed the level of inflammatory cytokines, including interleukin 6 (IL-6) and tumor necrosis factor (TNF) in HUVECs. We further investigated the regulatory mechanisms of the signal transducer and activator of transcription 3 (STAT3)/NF-κB signaling pathway in HUVECs by Western-blot analysis. We found that HUVECs cultured on 316L SS had increased cell proliferation and inflammation, and these can be inhibited by treatment with EGCG. EGCG reduced the secretion of IL-6 and TNF and decreased the expression of STAT3 and NF-κB in HUVECs cultured on 316L SS. Consequently, our study demonstrated that EGCG treatment ameliorates the proliferation of HUVEC when cultured with 316L SS, potentially by modulating the inflammation responses via the STAT3/NF-κB signaling pathways.

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.

Carboplatin and epigallocatechin-3-gallate synergistically induce cytotoxic effects in esophageal cancer cells

Background and purpose:

We aimed at evaluating the effects of combinatorial treatments with carboplatin and epigallocatechin-3-gallate (EGCG) on the KYSE-30 esophageal cancer (EC) cell line and elucidate the underlying mechanisms.

Experimental approach:

EC cells were harvested and exposed to increasing concentrations of carboplatin and EGCG to construct a dose-response plot. Cell inhibitory effects were assessed by the MTT method and apoptosis-related gene expression levels (caspases 8 and 9) and Bcl-2 mRNA were detected using real-time polymerase chain reaction. The lactate levels in the various treated cases were analyzed using the colorimetric assay kit. In addition, total antioxidant capacity was measured.

Findings/Results:

The results indicated that, following treatments with carboplatin in IC₂₀, IC₂₅, and IC₁₀ concentrations when combined with EGCG in similar concentrations, synergistically decreased cell viability versus single treatments of both agents. Also, in combined treatments at IC₂₀ and IC₂₅ of both agents the gene expression ratio of caspases 8 and 9 upregulated significantly compared to monotherapies (P < 0.05). Bcl-2 gene expression ratios were decreased in double agents treated cells versus monotherapies. Following treatment of KYSE-30 cells with carboplatin and EGCG in double combinations, lactate levels were significantly decreased compared with the untreated cells and single treatments (P < 0.05). Also, in IC₂₅, IC₂₀, and IC₁₀ concentrations of both agents the total antioxidant capacity levels were decreased versus monotherapies and untreated cells.

Conclusion and implications:

The presented study determined that treatment with carboplatin and EGCG was capable of promoting cytotoxicity in EC cells and inhibits the cancer progress. Combined treatments with low concentrations of carboplatin and EGCG may promote apoptosis induction and inhibit cell growth. These results confirmed the anticancer effects of carboplatin and EGCG and providing a base for additional use of EGCG to the EC treatment.

Epigallocatechin Gallate for Management of Heavy Metal-Induced Oxidative Stress: Mechanisms of Action, Efficacy, and Concerns

In this review, we highlight the effects of epigallocatechin gallate (EGCG) against toxicities induced by heavy metals (HMs). This most active green tea polyphenol was demonstrated to reduce HM toxicity in such cells and tissues as testis, liver, kidney, and neural cells. Several protective mechanisms that seem to play a pivotal role in EGCG-induced effects, including reactive oxygen species scavenging, HM chelation, activation of nuclear factor erythroid 2-related factor 2 (Nrf2), anti-inflammatory effects, and protection of mitochondria, are described. However, some studies, especially in vitro experiments, reported potentiation of harmful HM actions in the presence of EGCG. The adverse impact of EGCG on HM toxicity may be explained by such events as autooxidation of EGCG, EGCG-mediated iron (Fe3+) reduction, depletion of intracellular glutathione (GSH) levels, and disruption of mitochondrial functions. Furthermore, challenges hampering the potential EGCG application related to its low bioavailability and proper dosing are also discussed. Overall, in this review, we point out insights into mechanisms that might account for both the beneficial and adverse effects of EGCG in HM poisoning, which may have a bearing on the design of new therapeutics for HM intoxication therapy.

Sex-specific oxidative damage effects induced by BPA and its analogs on primary hippocampal neurons attenuated by EGCG

BPA analogs, including bisphenol S (BPS) and bisphenol B (BPB), have been used to replace BPA since it was banned to be added. To investigate whether BPA and its analogs cause oxidative damage effects on primary hippocampal neurons of rats, reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), mitochondrial membrane potential (MMP), apoptosis and cell viability assays were conducted after hippocampal neurons exposure to different concentrations of BPA, BPS, and BPB (1, 10, 100 nM and 1, 10, 100 μM). Moreover, the effects of EGCG (5 and 6 μM for male and female, respectively) added on neurons exposed to BPA were assessed. Results showed that 24 h exposure to these bisphenols (BPs) could increase the levels of ROS and contents of MDA, but reduce the activity of SOD significantly. A decline of cell viabilities accompanied with the increasing of apoptosis rates was observed after 7 d exposure to BPs and the reduction of MMP was also observed after 7 d exposure to BPA. Interestingly, BPS has the lower toxicity to hippocampal neurons compared with BPA and BPB. Non-monotonic dose-effect relationships between the concentrations of BPs and the cytotoxic effects were observed, and the effects of BPs on male hippocampal neurons are greater than those of female ones in general. While EGCG can protect neurons free of oxidative damages. In conclusion, the results suggest that BPs may induce sex-specific neurotoxic effects involving oxidative stress, which can be attenuated by EGCG, and males are more sensitive to BPs than females.

Cadmium induced BEAS-2B cells apoptosis and mitochondria damage via MAPK signaling pathway

Cadmium, a heavy metal pollutant in industrial production, is found in air, water and soil, which is harmful to human health and can lead to diseases, such as asthma, lung cancer, and emphysema. In this study, the toxicity of cadmium on human bronchial epithelial cells (BEAS-2B) was investigated. Cell viability, mitochondrial membrane potential, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with MTT assay, Rhodamine staining, DCFH-DA staining, Hoechst33258 staining and Western blot methods respectively. The results showed that the cell viability decreased, the mitochondrial membrane potential declined, ROS was accumulated and apoptotic rate raised in BEAS-2B cells. Meanwhile, the expression of B-cell lymphoma-2 (Bcl-2) was downregulated, while the expression of Bcl-2-associated X protein (Bax) and the cleaved caspase-3 was upregulated, which indicated mitochondria-mediated intrinsic apoptosis pathway was activated. Furthermore, the phosphorylation of JNK, ERK and p38 was enhanced respectively, which manifested that MAPK signaling pathways were activated. Therefore, it could be concluded that cadmium could increase intracellular ROS, result in cellular oxidative stress, activate JNK, ERK and p38 MAPK pathways and ultimately lead to apoptosis of BEAS-2B cells by activating mitochondria-mediated intrinsic apoptosis pathway. This study provided useful information to elucidate the toxicity of cadmium and revealed the possible mechanism for the occurrence of lung disease induced by cadmium.

Neuroprotective Potential of Verbascoside Isolated from Acanthus mollis L. Leaves through Its Enzymatic Inhibition and Free Radical Scavenging Ability

The phenomenon of today’s ageing population has increased interest in the search for new active substances that delay the onset and development of neurodegenerative diseases. In this respect, the search for natural compounds, mainly phenolic compounds, with neuroprotective activity has become the focus of growing interest. Verbascoside is a phenylethanoid that has already presented several pharmacological activities. The purpose of this study is to isolate and identify verbascoside from Acanthus mollis leaves. Consequently, its neuroprotective ability through enzymatic inhibition and free radical scavenging ability has been analyzed both in vitro and in cell culture assays. The antioxidant capacity of verbascoside was evaluated in vitro through total antioxidant capacity, DPPH^•, ^•OH, and O₂^•—scavenging activity assays. The effect of verbascoside on intracellular reactive oxygen species (ROS) levels of HepG2 and SH-SY5Y cell lines was studied in normal culture and under induced oxidative stress. The inhibitory ability of the phenylethanoid against several enzymes implied in neurodegenerative diseases (tyrosinase, MAO-A, and AChE) was analyzed in vitro. Verbascoside neuroprotective activity is at least in part related to its free radical scavenging ability. The effect of verbascoside on ROS production suggests its potential in the prevention of harmful cell redox changes and in boosting neuroprotection.

Cadmium sulfate induces apoptosis in planarians

With rapid socio-economic development, heavy metal pollution in water has become common and affects both environment and human health. Cadmium (Cd) has been recognized as one of the heavy metals which cause acute or chronic toxic effects if ingested. Although its toxicity is undisputed, the underlying molecular mechanisms in vivo are not fully understood. Planarians, a model organism famous for their regenerative prowess, have long been utilized to study the effects of chemical exposure. In this study, we observed apoptosis with TUNEL assay in planarians induced by cadmium sulfate (CdSO₄) in a dose-dependent manner. The apoptosis-related genes were detected with quantitative RT-PCR. Significant changes in c-Myc, P53, and BcL-2 were indicated, which may play a partial role in the regulation of the process of apoptosis in the planarians. H&E staining showed that Cd had obvious biological toxicity in the planarians. Here, new insights on metal toxicity mechanisms are provided, contributing to understand how CdSO₄ induces the pathological and physiological processes of apoptosis in the living bodies. Meanwhile, planarians are proved to be a freshwater pollution indicator and toxicological research model.

An updated review of protective effects of rosemary and its active constituents against natural and chemical toxicities

Natural and chemical toxic agents cause severe adverse effects on people's health in a variety of exposing ways. Herbal medications have taken into consideration as alternative safe treatments for toxicities. Rosmarinus officinalis also known as rosemary belongs to the Lamiaceae family. Rosemary and its constituents including carnosic acid, rosmarinic acid, and carnosol have a lot of benefits such as anti-inflammatory, antioxidant, anti-mutagenic, anti-bacterial, antiviral, antinociceptive, and neuroprotective activities. In this literate review, we focused on the protective effects of rosemary and its main compounds against natural and chemical toxicities in both in vitro and in vivo studies. The protective effects of rosemary and its components are mostly mediated through different mechanisms such as the inhibition of oxidative stress, reduction of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), cyclooxygenase-2 (COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis and mitogen-activated protein kinase (MAPK) signaling pathways.

Effect of epigallocatechin-3-gallate (EGCG) on embryos inseminated with oxidative stress-induced DNA damage sperm

Cryopreservation can induce damage in human spermatozoa through reactive oxygen species (ROS) generation. To reduce the potential risk of oxidative stress-induced sperm DNA damage, addition of different epigallocatechin-3-gallate (EGCG) concentrations were performed to determine the optimum concentration which was beneficial for IVF outcome for both fresh and frozen-thawed sperm. Next, the mouse sperm model exhibiting oxidative stress-induced DNA damage by exogenously treating with H₂O₂ but overcoming the low fertilization rate of frozen-thawed sperm was used to investigate the effect of EGCG on the embryonic development and the potential EGCG-mediated effects on ataxia telangiectasia mutated (ATM) pSer-1981 in zygotes, the latter was known for leading to the activation of major kinases involved in the DNA repair pathway and the cell cycle checkpoint pathway. We found the fertilization and embryonic development of embryos inseminated with frozen-thawed sperm was impaired compared to fresh sperm. EGCG promoted the development of embryos inseminated with both types of sperm at optimum concentration. In embryos inseminated with the H₂O₂ sperm, fertilization, embryonic development, and the time at which the cleavage rate of one-cell embryos reached ≥95% were not affected by EGCG treatment. However, the EGCG-treated group required less time to achieve 50% cleavage rate of one-cell embryos, and the EGCG-treated zygotes showed enhanced expression of ATM (pSer-1981) than the untreated group. EGCG at optimum concentrations may exert beneficial effects by modulating the ATM activation and moving up the time to enter into mitotic (M) phase.

ABBREVIATIONS

ROS: reactive oxygen species; EGCG: epigallocatechin-3-gallate; ATM: ataxia telangiectasia mutated; M: mitotic.

Molecular mechanisms of action of epigallocatechin gallate in cancer: Recent trends and advancement

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is an ester of epigallocatechin and gallic acid. EGCG, abundantly found in tea, is a polyphenolic flavonoid that has the potential to affect human health and disease. EGCG interacts with various recognized cellular targets and inhibits cancer cell proliferation by inducing apoptosis and cell cycle arrest. In addition, scientific evidence has illustrated the promising role of EGCG in inhibiting tumor cell metastasis and angiogenesis. It has also been found that EGCG may reverse drug resistance of cancer cells and could be a promising candidate for synergism studies. The prospective importance of EGCG in cancer treatment is owed to its natural origin, safety, and low cost which presents it as an attractive target for further development of novel cancer therapeutics. A major challenge with EGCG is its low bioavailability which is being targeted for improvement by encapsulating EGCG in nano-sized vehicles for further delivery. However, there are major limitations of the studies on EGCG, including study design, experimental bias, and inconsistent results and reproducibility among different study cohorts. Additionally, it is important to identify specific EGCG pharmacological targets in the tumor-specific signaling pathways for development of novel combined therapeutic treatments with EGCG. The present review highlights the ongoing development to identify cellular and molecular targets of EGCG in cancer. Furthermore, the role of nanotechnology-mediated EGCG combinations and delivery systems will also be discussed.

A review for physiological activities of EGCG and the role in improving fertility in humans/mammals

Epigallocatechin-3-gallate (EGCG) is a secondary metabolite in green tea, which has various physiological activities, including antioxidant, antitumor, and antiviral activities. Studies have shown that EGCG has a preventive effect on infertility by protecting germ cells and oocytes from damage. EGCG functions mainly through the regulation of ROS (reactive oxygen species) levels, which affect the expression of catalase (CAT), superoxide dismutase 1(SOD1), superoxide dismutase 2(SOD2), and glutathione peroxidase (GPx), has positive influence on other enzyme activities in germ cells and oocytes, and actively alters antioxidant activities. These enzymes above can inhibit the activation of extracellular signal-regulated proteins (Erk), induce apoptosis, and control the production of ROS in tissue cells. Here, we present a comprehensive overview of the mechanisms underlying the main physiological activities of EGCG, including antioxidant, antitumor, and antiviral activities, and their potential roles in male and female reproductive systems and fertility. This paper discusses the mechanisms by which EGCG retards the infertility of germ cells and oocytes and provides a supportive recommendation for improving fertility in humans and animals. We hope it will provide useful references for related research in mammalian reproduction.

Neuroprotection mediated by natural products and their chemical derivatives

Neuronal injuries can lead to various diseases such as neurodegenerative diseases, stroke, trauma, ischemia and, more specifically, glaucoma and optic neuritis. The cellular mechanisms that regulate neuronal death include calcium influx and calcium overload, excitatory amino acid release, oxidative stress, inflammation and microglial activation. Much attention has been paid to the effective prevention and treatment of neuroprotective drugs by natural products. This review summarizes the neuroprotective aspects of natural products, extracted from Panax ginseng, Camellia sinensis, soy and some other plants, and some of their chemical derivatives. Their antioxidative and anti-inflammatory action and their inhibition of apoptosis and microglial activation are assessed. This will provide new directions for the development of novel drugs and strategies to treat neurodegenerative diseases.

Can Plant Phenolic Compounds Protect the Skin from Airborne Particulate Matter?

The skin is directly exposed to the polluted atmospheric environment, and skin diseases, such as atopic dermatitis and acne vulgaris, can be induced or exacerbated by airborne particulate matter (PM). PM can also promote premature skin aging with its accompanying functional and morphological changes. PM-induced skin diseases and premature skin aging are largely mediated by reactive oxygen species (ROS), and the harmful effects of PM may be ameliorated by safe and effective natural antioxidants. Experimental studies have shown that the extracts and phenolic compounds derived from many plants, such as cocoa, green tea, grape, pomegranate, and some marine algae, have antioxidant and anti-inflammatory effects on PM-exposed cells. The phenolic compounds can decrease the levels of ROS in cells and/or enhance cellular antioxidant capacity and, thereby, can attenuate PM-induced oxidative damage to nucleic acids, proteins, and lipids. They also lower the levels of cytokines, chemokines, cell adhesion molecules, prostaglandins, and matrix metalloproteinases implicated in cellular inflammatory responses to PM. Although there is still much research to be done, current studies in this field suggest that plant-derived phenolic compounds may have a protective effect on skin exposed to high levels of air pollution.

A Selective Role of Dietary Anthocyanins and Flavan-3-ols in Reducing the Risk of Type 2 Diabetes Mellitus: A Review of Recent Evidence

Type 2 diabetes mellitus (T2DM) is the most common form of DM and its prevalence is increasing worldwide. Because it is a progressive disease, prevention, early detection and disease course modification are possible. Diet plays a critical role in reducing T2DM risk. Therapeutic dietary approaches routinely recommend diets high in plant foods (i.e., vegetables, fruits, whole-grains). In addition to essential micronutrients and fiber, plant-based diets contain a wide-variety of polyphenols, specifically flavonoid compounds. Evidence suggests that flavonoids may confer specific benefits for T2DM risk reduction through pathways influencing glucose absorption and insulin sensitivity and/or secretion. The present review assesses the relationship between dietary flavonoids and diabetes risk reduction reviewing current epidemiology and clinical research. Collectively, the research indicates that certain flavonoids, explicitly anthocyanins and flavan-3-ols and foods rich in these compounds, may have an important role in dietary algorithms aimed to address diabetes risk factors and the development of T2DM.

Anti-oxidative or anti-inflammatory additives reduce ischemia/reperfusions injury in an animal model of cardiopulmonary bypass

Severe inborn cardiac malformations are typically corrected in cardioplegia, with a cardio-pulmonary bypass (CPB) taking over body circulation. During the operation the arrested hearts are subjected to a global ischemia/reperfusion injury. Although the applied cardioplegic solutions have a certain protective effect, application of additional substances to reduce cardiac damage are of interest.

18 domestic piglets (10–15 kg) were subjected to a 90 min CPB and a 120 min reperfusion phase without or with the application of epigallocatechin-3-gallate (10 mg/kg body weight) or minocycline (4 mg/kg body weight), with both drugs given before and after CPB. 18 additional sham-operated piglets without or with epigallocatechin-3-gallate or minocycline served as controls. In total 36 piglets were analyzed (3 CPB-groups and 3 control groups without or with epigallocatechin-3-gallate or minocycline respectively; 6 piglets per group). Hemodynamic and blood parameters and ATP-measurements were assessed. Moreover, a histological evaluation of the heart muscle was performed.

Results

Piglets of the CPB-group needed more catecholamine support to achieve sufficient blood pressure. Ejection fraction and cardiac output were not different between the 6 groups. However, cardiac ATP-levels and blood lactate were significantly lower and creatine kinase was significantly higher in the three CPB-groups. Markers of apoptosis, hypoxia, nitrosative and oxidative stress were significantly elevated in hearts of the CPB-group. Nevertheless, addition of epigallocatechin-3-gallate or minocycline significantly reduced markers of myocardial damage. Noteworthy, EGCG was more effective in reducing markers of hypoxia, whereas minocycline more efficiently decreased inflammation.

Conclusions

While epigallocatechin-3-gallate or minocycline did not improve cardiac hemodynamics, markers of myocardial damage were significantly lower in the CPB-groups with epigallocatechin-3-gallate or minocycline supplementation.

Inhibitory Effects of (-)-Epigallocatechin-3-gallate on Esophageal Cancer

There is epidemiological evidence showing that drinking green tea can lower the risk of esophageal cancer (EC). The effect is mainly attributed to tea polyphenols and their most abundant component, (−)-epigallocatechin-3-gallate (EGCG). The possible mechanisms of tumorigenesis inhibition of EGCG include its suppressive effects on cancer cell proliferation, angiogenesis, DNA methylation, metastasis and oxidant stress. EGCG modulates multiple signal transduction and metabolic signaling pathways involving in EC. A synergistic effect was also observed when EGCG was used in combination with other treatment methods.

Protective effect of tea against lead and cadmium-induced oxidative stress-a review

Exposure to Cd and Pb reduces the activity of antioxidant enzymes, which points to a decrease in the antioxidant potential of the body as a result of supplying factors which enhance cellular oxidation processes. Man is exposed to the effects of toxic metals because they are present in the environment, including in food. Since no effective ways to reduce the concentrations of Cd an Pb in food exist, studies are undertaken to develop methods of reducing their toxic effect on the body through chelating these metals using nutrients (which reduces their absorption by tissues) or increasing the oxidative capacity of the body (which decreases the possibility of inducing oxidative damage to internal organs). Studies performed on laboratory animals have shown that the use of tea infusions fulfil both functions.

Differences in the Effects of EGCG on Chromosomal Stability and Cell Growth between Normal and Colon Cancer Cells

The tea catechin epigallocatechin-3-gallate (EGCG) proved to be the most potent physiologically active tea compound in vitro. It possesses antioxidant as well as pro-oxidant properties. EGCG has the effect of inducing apoptosis of tumor cells and inhibiting cell proliferation. Whether this effect is associated with the antioxidant or pro-oxidative effects of EGCG affecting the genome stability of normal and cancer cells has not been confirmed. Here, we selected Human normal colon epithelial cells NCM460 and colon adenocarcinoma cells COLO205 to investigate the effects of EGCG (0–40 μg/mL) on the genome stability and cell growth status. Chromosomal instability (CIN), nuclear division index (NDI), and apoptosis was measured by cytokinesis-block micronucleus assay (CBMN), and the expression of core genes in mismatch repair (hMLMLH1 and hMSH2) was examined by RT-qPCR. We found that EGCG significantly reduced CIN and apoptosis rate of NCM460 at all concentrations (5–40 μg/mL) and treatment time, EGCG at 5 μg/mL promoted cell division; EGCG could significantly induce chromosome instability in COLO205 cells and trigger apoptosis and inhibition of cell division. These results suggest that EGCG exhibits different genetic and cytological effects in normal and colon cancer cells.

Hepatotoxicity of benzotriazole and its effect on the cadmium induced toxicity in zebrafish Danio rerio

As an emerging contaminant, 1-H-benzotriazole (1H-BTR) has been detected in the engineered and natural aquatic environments, which usually coexists with heavy metals and causes combined pollution. In the present study, wild-type and transgenic zebrafish Danio rerio were used to explore the acute toxicity as well as the single and joint hepatotoxicity of cadmium (Cd) and 1H-BTR. Although the acute toxicity of 1H-BTR to zebrafish was low, increased expression of liver-specific fatty acid binding protein was observed in transgenic zebrafish when the embryos were exposed to 5.0 μM of 1H-BTR for 30 days. Besides, co-exposure to 1H-BTR not only reduced the acute toxic effects induced by Cd, but also alleviated the Cd-induced liver atrophy in transgenic fish. Correspondingly, effects of combined exposure to 1H-BTR on the Cd-induced expressions of several signal pathway-related genes and superoxide dismutase and glutathione-s-transferase proteins were studied. Based on the determination of Cd bioaccumulation in fish and the complexing stability constant (β) of Cd-BTR complex in solution, the detoxification mechanism of co-existing 1H-BTR on Cd to the zebrafish was discussed.

EGCG Maintains Th1/Th2 Balance and Mitigates Ulcerative Colitis Induced by Dextran Sulfate Sodium through TLR4/MyD88/NF-κB Signaling Pathway in Rats

OBJECTIVE

To observe the protective effect of epigallocatechin gallate (EGCG) on dextran sulfate sodium- (DSS-) induced ulcerative colitis in rats and to explore the roles of TLR4/MyD88/NF-κB signaling pathway.

METHODS

Rat models of ulcerative colitis were established by giving DSS. EGCG (50 mg/kg/d) was given to assess disease activity index. HE staining was applied to observe histological changes. ELISA and qPCR detected the expression of inflammatory factors. Flow cytometry was used to measure the percentage of CD4⁺IFN-γ⁺ and CD4⁺IL-4⁺ in the spleen and colon. TLR4 antagonist E5564 was given in each group. Flow cytometry was utilized to detect CD4⁺IFN-γ⁺ and CD4⁺IL-4⁺ cells. Immunohistochemistry, qPCR, and western blot assay were applied to measure the expression of TLR4, MyD88, and NF-κB.

RESULTS

EGCG improved the intestinal mucosal injury in rats, inhibited production of inflammatory factors, maintained the balance of Th1/Th2, and reduced the expression of TLR4, MyD88, and NF-κB. After TLR4 antagonism, the protective effect of EGCG on intestinal mucosal injury was weakened in rats with ulcerative colitis, and the expressions of inflammatory factors were upregulated.

CONCLUSION

EGCG can inhibit the intestinal inflammatory response by reducing the severity of ulcerative colitis and maintaining the Th1/Th2 balance through the TLR4/MyD88/NF-κB signaling pathway.

Protective effects of green tea and its main constituents against natural and chemical toxins: A comprehensive review

Toxins are natural or chemical poisonous substances with severe side effects on health. Humans are generally exposed by widespread toxic contaminations via air, soil, water, food, fruits and vegetables. Determining a critical antidote agent with extensive effects on different toxins is an ultimate goal for all toxicologists. Traditional medicine is currently perceived as a safe and natural approach against toxins. In this regard, we focused on the protective effects of green tea (Camellia sinensis) and its main components such as catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate as a principal source of antioxidants against both natural and chemical toxins. This literate review demonstrates that protective effects of green tea and its constituents were mainly attributed to their anti-oxidative, radical scavenging, chelating, anti-apoptotic properties and modulating inflammatory responses. Although, some studies reveal they have protective effects by increasing toxin metabolism and neutralizing PLA₂, proteases, hyaluronidase and l-amino acid oxidase enzymes.

Epigallocatechin-3-gallate suppresses alveolar epithelial cell apoptosis in seawater aspiration-induced acute lung injury via inhibiting STAT1-caspase-3/p21 associated pathway

The apoptosis of alveolar epithelial cells is important in seawater aspiration‑induced acute lung injury (ALI). The present study aimed to investigate whether epigallocatechin-3-gallate (EGCG) is able to suppress apoptosis in alveolar epithelial cells in seawater aspiration‑induced ALI in vivo and in vitro, and the possible mechanisms underlying it. The results indicated that seawater aspiration‑induced ALI in rats is accompanied by increased apoptosis in lung tissue cells and the expression of apoptosis‑associated proteins, caspase‑3 and p21. EGCG pretreatment significantly ameliorated seawater aspiration‑induced ALI. Furthermore, EGCG decreased seawater aspiration‑induced apoptosis and the expression of caspase‑3 and p21 in lung tissue cells. Seawater‑challenged A549 cells experienced increased apoptosis and elevated levels of phosphorylated‑signal transducer and activator of transcription 1 (P‑STAT1). EGCG pretreatment of the cells resulted in significantly decreased seawater‑induced apoptosis and lower levels of STAT1 and P‑STAT1 in A549 cells. This suggests that EGCG suppresses alveolar epithelial cell apoptosis in seawater aspiration‑induced ALI via inhibiting the STAT1-caspase-3/p21 associated pathway.

EGCG Attenuates Uric Acid-Induced Inflammatory and Oxidative Stress Responses by Medicating the NOTCH Pathway

Background. The aim of this study is to investigate whether (-)-epigallocatechin-3-gallate (EGCG) can prevent the UA-induced inflammatory effect of human umbilical vein endothelial cells (HUVEC) and the involved mechanisms in vitro. Methods. HUVEC were subjected to uric acid (UA) with or without EGCG treatment. RT-PCR and western blots were performed to determine the level of inflammation marker. The antioxidant activity was evaluated by measuring scavenged reactive oxygen species (ROS). Functional studies of the role of Notch-1 in HUVEC lines were performed using RNA interference analyses. Results. UA significantly increased the expressions of IL-6, ICAM-1, TNF-α, and MCP-1 and the production of ROS in HUVEC. Meanwhile, the expression of Notch-1 and its downstream effects significantly increased. Using siRNA, inhibition of Notch-1 signaling significantly impeded the expressions of inflammatory cytokines under UA treatment. Interestingly, EGCG suppressed the expressions of inflammatory cytokines and the generation of ROS. Western blot analysis of Notch-1 showed that EGCG significantly decreased the expressions of inflammatory cytokines through Notch-1 signaling pathways. Conclusions. In summary, our findings indicated that Notch-1 plays an important role in the UA-induced inflammatory response, and the downregulation of Notch-1 by EGCG could be an effective approach to decrease inflammation and oxidative stress induced by UA.

Epigallocatechin Gallate: A Review of Its Beneficial Properties to Prevent Metabolic Syndrome

Obesity and being overweight are linked with a cluster of metabolic and vascular disorders that have been termed the metabolic syndrome. This syndrome promotes the incidence of cardiovascular diseases that are an important public health problem because they represent a major cause of death worldwide. Whereas there is not a universally-accepted set of diagnostic criteria, most expert groups agree that this syndrome is defined by an endothelial dysfunction, an impaired insulin sensitivity and hyperglycemia, dyslipidemia, abdominal obesity and hypertension. Epidemiological studies suggest that the beneficial cardiovascular health effects of diets rich in green tea are, in part, mediated by their flavonoid content, with particular benefits provided by members of this family such as epigallocatechin gallate (EGCG). Although their bioavailability is discussed, various studies suggest that EGCG modulates cellular and molecular mechanisms of various symptoms leading to metabolic syndrome. Therefore, according to in vitro and in vivo model data, this review attempts to increase our understanding about the beneficial properties of EGCG to prevent metabolic syndrome.

Protective effects of acteoside against X‑ray‑induced damage in human skin fibroblasts

To investigate the protective effects of acteoside against apoptosis induced by X-ray radiation in human skin fibroblasts (HSFs), the cells were divided into the following groups: Control group; X-ray radiation group; acteoside group, in which the confluent cells were preincubated with 50 μg/ml acteoside for 2 h followed by radiation; and positive control group, in which the cells were preincubated with 50 μg/ml paeoniflorin followed by radiation. For the radiation, HSF cells preincubated with acteoside or paeoniflorin were exposed to X-ray beams at a dose-rate of 3 Gy/min (16 Gy in total). Cell viability, apoptosis and intracellular alteration of redox were monitored by MTT and flow cytometry. Compared with the radiation group, the number of cells arrested at the G0/G1 phase was significantly reduced in the acteoside and paeoniflorin groups, respectively (P<0.05). X-ray radiation induced marked apoptosis in HSF cells and acteoside reversed this effect. Compared with the radiation group, the generation of intracellular reactive oxygen species (ROS) was abrogated by pre-incubation with acteoside or paeoniflorin (P<0.05). In addition, the upregulation of pro-caspase-3 induced by radiation was reversed by acteoside or paeoniflorin. Radiation could induce upregulation of Bax and downregulation of Bcl-2; however, it was reversed completely after administration of acteoside or paeoniflorin. Furthermore, the enhanced expression of ERK and JNK induced by radiation was reversed by acteoside or paeoniflorin. Acteoside could protect the cells from X-ray induced damage through enhancing the scavenging activity of ROS, decreasing the Bax/Bcl-2 ratio and downregulating the activity of procaspase-3, as well as modulating the mitogen-activated protein kinase signaling pathways.

Epigallocatechin-3-gallate reduces tubular cell apoptosis in mice with ureteral obstruction

BACKGROUND

Tubular cell apoptosis plays a crucial role in different kinds of renal diseases. Epigallocatechin-3-gallate (EGCG), a polyphenol extracted from green tea, has been shown to inhibit renal fibrosis in unilateral ureteral obstruction (UUO) mice, but its role in preventing tubular cell apoptosis and the underlying signaling mechanisms still remains unclear.

MATERIALS AND METHODS

Mice subjected to UUO were intraperitoneally administered EGCG (5 mg/kg) for 14 d. Normal rat kidney proximal tubular epithelial cell line NRK-52E was induced by transforming growth factor β1 (TGF-β1). Periodic acid-schiff and Masson's trichrome staining was used for histologic study. TUNEL, Hoechst staining, and flow cytometry analysis were used to measure the apoptotic status of tubular cells. Western blotting was used to determine the expression of apoptotic-associated proteins and mitogen-activated protein kinase pathway proteins.

RESULTS

EGCG significantly attenuated tubular injury and renal tubulointerstitial fibrosis in the obstructed kidneys of UUO mice. In addition, EGCG prevented UUO and TGF-β1-induced tubular apoptosis in a dose-dependent manner. In parallel, protein expression of B-clell lymphoma-2 (Bcl-2) was upregulated and protein expressions of Bcl-2 accosiated X protein (Bax), cleaved caspase 3, and cleaved poly ADP-ribose polymerase (PARP) were downregulated by EGCG. Furthermore, UUO and TGF-β1-stimulated phosphorylation of mitogen-activated protein kinase was inhibited by EGCG.

CONCLUSIONS

EGCG effectively reduces tubular cell apoptosis induced by UUO and may have potential as a clinical treatment in patients with chronic kidney disease.

A prospective phase II trial of EGCG in treatment of acute radiation-induced esophagitis for stage III lung cancer

BACKGROUND

Acute radiation-induced esophagitis (ARIE) is one of main toxicities complicated by thoracic radiotherapy, influencing patients' quality of life and radiotherapy proceeding seriously. It is difficult to be cured rapidly so far. Our phase I trial preliminarily showed that EGCG may be a promising strategy in the treatment of ARIE.

MATERIALS AND METHODS

We prospectively enrolled patients with stage III lung cancer from the Shandong Tumor Hospital & Institute in China from January 2013 to September 2014. All patients received concurrent or sequential chemo-radiotherapy, or radiotherapy only. EGCG was administrated once ARIE appeared. EGCG was given with the concentration of 440μmol/L during radiotherapy and additionally two weeks after radiotherapy. RTOG score, dysphagia and pain related to esophagitis were recorded every week.

RESULTS

Thirty-seven patients with stage IIIA and IIIB lung cancer were enrolled in this trial. In comparison to the original, the RTOG score in the 1st, 2nd, 3rd, 4th, 5th week after EGCG prescription and the 1st, 2nd week after radiotherapy decreased significantly (P=0.002, 0.000, 0.000, 0.001, 0.102, 0.000, 0.000, respectively). The pain score of each week was significantly lower than the baseline (P=0.000, 0.000, 0.000, 0.000, 0.006, 0.000, 0.000, respectively).

CONCLUSION

This trial confirmed that the oral administration of EGCG is an effective and safe method to deal with ARIE. A phase III randomized controlled trial is expected to further corroborate the consequence of EGCG in ARIE treatment.

Hippocampal Neuroprotection by Minocycline and Epigallo-Catechin-3-Gallate Against Cardiopulmonary Bypass-Associated Injury

Surgical correction of congenital cardiac malformations mostly implies the use of cardiopulmonary bypass (CPB). However, a possible negative impact of CPB on cerebral structures like the hippocampus cannot be neglected. Therefore, we investigated the effect of CPB on hippocampus CA1 and CA3 regions without or with the addition of epigallocatechin-3-gallate (EGCG) or minocycline. We studied 42 piglets and divided them into six experimental groups: control without or with EGCG or minocycline, CPB without or with EGCG or minocycline. The piglets underwent 90 minutes CPB and subsequently, a 120-minute recovery and reperfusion phase. Thereafter, histology of the hippocampus was performed and the adenosine triphosphate (ATP) content was measured. Histologic evaluation revealed that CPB produced a significant peri-cellular edema in both CA regions. Moreover, we found an increased number of cells stained with markers for hypoxia, apoptosis and nitrosative stress. Most of these alterations were significantly reduced to or near to control levels by application of EGCG or minocycline. ATP content was significantly reduced within the hippocampus after CPB. This reduction could not be antagonized by EGCG or minocycline. In conclusion, CPB had a significant negative impact on the integrity of hippocampal neural cells. This cellular damage could be significantly attenuated by addition of EGCG or minocycline.

Epigallocatechingallate inhibits migration of human uveal melanoma cells via downregulation of matrix metalloproteinase-2 activity and ERK1/2 pathway

The effects of epigallocatechingallate (EGCG) on the migration and expression of MMP-2 of uveal melanoma cells have not been reported. We studied this effect and relevant signaling pathways in a human uveal melanoma cell line (M17). MTT study found that EGCG did not affect the cell viability of M17 cells up to 100 µM. Wound-healing assay showed that EGCG significantly reduced the migration of melanoma cells in a dose-dependent manner from 20 to 100 µM. Gelatin zymography showed that secreted MMP-2 activity was dose-dependently inhibited by EGCG, whereas the MMP-2 expression at protein and mRNA levels was not affected as determined by western blot and RT-PCR analysis. EGCG significantly increased the expressions of MMP-2 endogenous inhibitors (TIMP-2 and RECK) in M17 cells. Western blot analysis of MAPK signal pathways showed that EGCG significantly decreased phosphorylated ERK1/2 levels, but not p38 and JNK levels, in melanoma cells. ERK1/2 inhibitors also reduced the migration and activity of MMP-2 in M17 cells. The present study suggested EGCG at nontoxic levels could inhibit migration of melanoma cells via downregulation of activities of secreted MMP-2 through the inhibition of the ERK1/2 phosphorylation. Therefore, EGCG may be a promising agent to be explored for the prevention of metastasis of uveal melanoma.