Effects of green tea catechins on nonalcoholic steatohepatitis (NASH) patients

Unravelling the complexities of non-alcoholic steatohepatitis: The role of metabolism, transporters, and herb-drug interactions

Nonalcoholic fatty liver disease (NAFLD) is a mainstream halting liver disease with high prevalence in North America, Europe, and other world regions. It is an advanced form of NAFLD caused by the amassing of fat in the liver and can progress to the more severe form known as non-alcoholic steatohepatitis (NASH). Until recently, there was no authorized pharmacotherapy reported for NASH, and to improve the patient's metabolic syndrome, the focus is mainly on lifestyle modification, weight loss, ensuring a healthy diet, and increased physical activity; however, the recent approval of Rezdiffra (Resmetirom) by the US FDA may change this narrative. As per the reported studies, there is an increased articulation of uptake and efflux transporters of the liver, including OATP and MRP, in NASH, leading to changes in the drug's pharmacokinetic properties. This increase leads to alterations in the pharmacokinetic properties of drugs. Furthermore, modifications in Cytochrome P450 (CYP) enzymes can have a significant impact on these properties. Xenobiotics are metabolized primarily in the liver and constitute liver enzymes and transporters. This review aims to delve into the role of metabolism, transport, and potential herb-drug interactions in the context of NASH.

Regulatory Effects and Molecular Mechanisms of Tea and Its Active Compounds on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease, is a multifactorial disease resulting from the interaction between environment, genetic background, and metabolic stress. Most treatments for NAFLD include dietary intervention and exercise show limited efficacy due to the complex mechanisms involved in NAFLD. Meanwhile, drug therapy is accompanied by serious side effects. The development of high-efficiency natural supplements is a sustainable strategy for the prevention and treatment of NAFLD. As the second most consumed beverage, tea has health benefits that have been widely recognized. Nevertheless, the intervention of tea active compounds in NAFLD has received limited attention. Tea contains abundant bioactive compounds with potential effects on NAFLD, such as catechins, flavonoids, theanine, tea pigments, and tea polysaccharides. We reviewed the intrinsic and environmental factors and pathogenic mechanisms that affect the occurrence and development of NAFLD, and summarized the influences of exercise, drugs, diet, and tea drinking on NAFLD. On this basis, we further analyzed the potential effects and molecular regulatory mechanisms of tea active compounds on NAFLD and proposed future development directions. This review hopes to provide novel insights into the development and application of tea active compounds in the prevention and treatment of NAFLD.

Calluna vulgaris Crude Extract Reverses Liver Steatosis and Insulin Resistance-Associated-Brain Lesion Induced by CCl4 Administration

Fatty liver (FL) is one of the most prevalent diseases in the world, characterized by insulin resistance and hyperlipidemia, which consequently lead to neurodegenerative disorders through the induction of oxidative stress-inflammatory axis, which alters the neurotransmitters’ levels. Calluna vulgaris (CV), also known as heather, has anti-inflammatory and antidepressant properties, making it a promising candidate for treating steatosis and brain lesions. This study aimed to assess the prophylactic and therapeutic effect of CV extract on brain dysfunction associated with steatosis. FL was induced in rats by CCl4 oral administration (50 µL/Kg in olive oil three times/week) for six weeks. The protection group received 200 mg/kg CV extract orally for two weeks before and two weeks during FL induction, while the treatment group was orally administered CV extract after FL induction for one month. The biochemical parameters revealed that CCl4 administration induced hepatotoxicity as blood-liver function parameters (AST, ALT, ALP, protein, and LDH) were increased by 1.8, 1.4, 2, 2.4, and 1.2-fold, respectively. Moreover, insulin resistance was characterized by a two-fold increase in the glucose, insulin, and lipid profile when compared to control one, at p < 0.05. Steatosis liver demonstrated a two-fold increase in all following parameters— acetaldehyde (AC), prooxidant (TBARS), acetylcholine esterase (AChE), monoamine oxidase (MAO), hyaluronidase, and ATPase—when compared to control one, at p < 0.05. CCl4 administration led to brain lesions where the brain level of TBARS, insulin, cholesterol, AChE, and MAO was progressively increased by 2, 1.6, 2.2, 4, and 1.6-fold, respectively, that was associated with reduced glucose (8-fold) and GSH (2-fold) than that of control level, at p < 0.05. CV extract as a prophylactic and therapeutic agent increased GSH and decreased TBARS of both the liver and brain than that of induced group, at p < 0.05, normalized the activities of AChE and MAO, and increased insulin sensitivity where they successfully decreased the HOMA-IR, glucose, TG, and cholesterol compared to than that of induced group, at p < 0.05. This positive effect of CV extract contributed to the presence of polyphenolic compounds such as catechins (5.501 ± 0.056 µg/g extract), gallic (3.525 ± 0.143 µg/g) extract, and protocatechuic acid (2.719 ± 0.132 µg/g extract). Therefore, we concluded that FL induced brain dysfunction through the formation of ROS and elevation of insulin and lipid inside the brain tissue, which alter the amount of neurotransmitter and cellular energy production. Rich in polyphenolic compounds, CV extract functions as an antioxidant, antidiabetic, hepatoprotective, inhibitor of neurotransmitter catabolizing enzymes, and a regulator for energy production. Therefore, it can be used as a preventative or treatment for NAFLD and brain damage.

The effects of green tea supplementation on cardiovascular risk factors: A systematic review and meta-analysis

Purpose

A bulk of observational studies have revealed the protective role of green tea supplementation in cardiovascular diseases. The current systematic review and meta-analysis study aimed to establish the effects of green tea supplementation on cardiovascular risk factors including lipid profile, blood pressure, glycemic control markers and CRP.

Methods

A systematic literature search of randomized clinical trials (RCTs) that investigated the effects of green tea supplementation and cardiovascular risk factors was undertaken in online databases including PubMed/Medline, Scopus, Web of Science, and Embase using a combination of green tea and cardiovascular risk factors search terms. Meta-analyses were carried out using a random-effects model. The I2 index was used to assess the heterogeneity of RCTs.

Results

Among the initial 11,286 studies that were identified from electronic databases search, 55 eligible RCTs with 63 effect sizes were eligible. Results from the random effects meta-analysis showed that GTE supplementation significantly reduced TC (WMD = -7.62; 95% CI: -10.51, -4.73; P = < 0.001), LDL-C (WMD = -5.80; 95% CI: -8.30, -3.30; P = < 0.001), FBS (WMD = -1.67; 95% CI: -2.58, -0.75; P = < 0.001), HbA1c (WMD = -0.15; 95% CI: -0.26, -0.04; P = 0.008), DBP (WMD = -0.87; 95% CI: -1.45, -0.29; P = 0.003), while increasing HDL-C (WMD = 1.85; 95% CI: 0.87, 2.84; P = 0.010). Subgroup analyses based on the duration of supplementation (≥ 12 vs. < 12 weeks), dose of green tea extract (GTE) (≥1,000 vs. < 1,000 mg/d), sex (male, female, and both), baseline serum levels of lipid profile, and glycemic control factors demonstrated different results for some risk factors.

Conclusion

The current study suggests improvements in the lipid and glycemic profiles following green tea supplementation. These findings support previous evidence showing the health benefits of green tea supplementation on cardiometabolic risk factors.

The effect of Green green tea consumption on body mass index, lipoprotein, liver enzymes, and liver cancer: An updated systemic review incorporating a meta-analysis

INTRODUCTION

Green tea is related to the reduction of liver enzymes, lipoprotein, and body mass index. However, some reports related green tea to the risk of developing liver cancer, but their outcomes were conflicting. Hence, the present study aimed to determine the relationship between green tea intake and lipoprotein, liver enzymes, body mass index, and liver cancer.

METHODS

A systematic literature search up to January 2022 was performed and 22 studies with a total of 169599 subjects participated in the studies with 97316 subjects of them used green tea intake. Odds ratio (OR) or standardized mean difference (MD) with 95% confidence intervals (CIs) was calculated to evaluate the relationship between green tea intake and lipoprotein, liver enzymes, body mass index, and liver cancer using the dichotomous or the contentious method with a random effect model.

RESULTS

Green tea intake significantly lowered the risk of developing liver cancer (OR, 0.85; 95% CI, 0.74 to 0.97, p = 0.02), and body mass index (MD, -0.69; 95% CI, -0.95to -0.42, p < 0.001) compared to no green tea intake. Also, there was a significant lowering effect of green tea intake on liver enzymes including alanine aminotransferase (MD, -0.65; 95% CI, -0.92 to -0.38, p < 0.001), and aspartate aminotransferase (MD, -0.77; 95% CI, -1.40 to -0.14, p = 0.02) compared to no green tea intake. There was also a significant lowering effect of green tea intake on lipoprotein including triglycerides (MD, -0.70; 95% CI, -1.35 to -0.04, p = 0.04), total cholesterol (MD, -0.39; 95% CI, -0.74 to -0.04, p = 0.03) and law-density lipoprotein (MD, -0.44; 95% CI, -0.69- -0.19, p < 0.001) compared to no green tea intake. However, no significant different was found between green tea intake and no green tea intake on high-density lipoprotein (MD, 0.16; 95% CI, -0.11 to 0.44, p = 0.24).

CONCLUSIONS

Based on this meta-analysis, green tea intake had a significant lowering effect on the risk of developing liver cancer and had a significantly improving effect on body mass index, liver enzymes, and lipoprotein compared to no green tea intake. These results suggest that green tea may be added to the daily dietary program to improve cardiovascular status with no possible risk of liver cancer. It even may have a protecting effect against liver cancer in the usual daily number of cups.

Green tea polyphenol epigallocatechin-3-gallate alleviates nonalcoholic fatty liver disease and ameliorates intestinal immunity in mice fed a high-fat diet

Green tea polyphenol epigallocatechin-3-gallate (EGCG) may help prevent metabolic syndrome and nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanisms of its protective effects are complicated and remain unclear. With the gut-liver axis theory as a foundation, the present study investigated the effects of EGCG on intestinal mucosal immunity in male C57BL/6 mice fed a high-fat Western diet or the diet supplemented with 0.4% dietary EGCG (w/w) for 14 weeks. Dietary EGCG supplementation effectively prevented changes-including excessive accumulation of visceral and hepatic fat, abnormal liver function, and elevated concentrations of serum and liver inflammatory cytokines-known to be caused by high-fat diets. In addition, serum lipopolysaccharide concentrations decreased by 94.3%. RNA sequencing data of differentially expressed genes in ileal samples among three groups indicated that most of the pathways in the Kyoto Encyclopedia of Genes and Genomes in the first 20 enrichment levels were related to immunity and inflammatory reactions. Real-time reverse transcription quantitative polymerase chain reaction was used to determine alterations in expression levels of key genes related to intestinal immune function and inflammatory responses from ileal and colonic samples. Changes in secretory immunoglobulin A in the small intestine, serum, and feces further demonstrated improved intestinal mucosal immunity in the EGCG-treated mice. In conclusion, dietary EGCG effectively prevented the development of NAFLD and significantly improved intestinal mucosal immunity in mice with obesity induced by a high-fat diet. However, whether improved intestinal immune function is the key mechanism underlying the health benefits of dietary EGCG warrants further research.

Green Tea and Epigallocatechin Gallate (EGCG) for the Management of Nonalcoholic Fatty Liver Diseases (NAFLD): Insights into the Role of Oxidative Stress and Antioxidant Mechanism

Nonalcoholic fatty liver diseases (NAFLD) represent a set of liver disorders progressing from steatosis to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma, which induce huge burden to human health. Many pathophysiological factors are considered to influence NAFLD in a parallel pattern, involving insulin resistance, oxidative stress, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory cascades, fibrogenic reaction, etc. However, the underlying mechanisms, including those that induce NAFLD development, have not been fully understood. Specifically, oxidative stress, mainly mediated by excessive accumulation of reactive oxygen species, has participated in the multiple NAFLD-related signaling by serving as an accelerator. Ameliorating oxidative stress and maintaining redox homeostasis may be a promising approach for the management of NAFLD. Green tea is one of the most important dietary resources of natural antioxidants, above which epigallocatechin gallate (EGCG) notably contributes to its antioxidative action. Accumulative evidence from randomized clinical trials, systematic reviews, and meta-analysis has revealed the beneficial functions of green tea and EGCG in preventing and managing NAFLD, with acceptable safety in the patients. Abundant animal and cellular studies have demonstrated that green tea and EGCG may protect against NAFLD initiation and development by alleviating oxidative stress and the related metabolism dysfunction, inflammation, fibrosis, and tumorigenesis. The targeted signaling pathways may include, but are not limited to, NRF2, AMPK, SIRT1, NF-κB, TLR4/MYD88, TGF-β/SMAD, and PI3K/Akt/FoxO1, etc. In this review, we thoroughly discuss the oxidative stress-related mechanisms involved in NAFLD development, as well as summarize the protective effects and underlying mechanisms of green tea and EGCG against NAFLD.

The role of biofactors in the prevention and treatment of age-related diseases

The present demographic changes toward an aging society caused a rise in the number of senior citizens and the incidence and burden of age-related diseases (such as cardiovascular diseases [CVD], cancer, nonalcoholic fatty liver disease [NAFLD], diabetes mellitus, and dementia), of which nearly half is attributable to the population ≥60 years of age. Deficiencies in individual nutrients have been associated with increased risks for age-related diseases and high intakes and/or blood concentrations with risk reduction. Nutrition in general and the dietary intake of essential and nonessential biofactors is a major determinant of human health, the risk to develop age-related diseases, and ultimately of mortality in the older population. These biofactors can be a cost-effective strategy to prevent or, in some cases, even treat age-related diseases. Examples reviewed herein include omega-3 fatty acids and dietary fiber for the prevention of CVD, α-tocopherol (vitamin E) for the treatment of biopsy-proven nonalcoholic steatohepatitis, vitamin D for the prevention of neurodegenerative diseases, thiamine and α-lipoic acid for the treatment of diabetic neuropathy, and the role of folate in cancer epigenetics. This list of potentially helpful biofactors in the prevention and treatment of age-related diseases, however, is not exhaustive and many more examples exist. Furthermore, since there is currently no generally accepted definition of the term biofactors, we here propose a definition that, when adopted by scientists, will enable a harmonization and consistent use of the term in the scientific literature.

Epigallocatechin-3-gallate (EGCG) attenuates non-alcoholic fatty liver disease via modulating the interaction between gut microbiota and bile acids

The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from simple hepatic steatosis commonly associated with obesity, to non-alcoholic steatohepatitis, which can progress to fibrosis, cirrhosis and hepatocellular carcinoma. Recent reports have indicated the crucial role of gut microbiota and their metabolites in the progression of NAFLD. In the present review, we demonstrated the influence of oral administration of (-)-epigallocatechin-3-gallate (EGCG) on the gut microbiota, serum bile acid profile, and gene expression in the liver in mice fed a high-fat diet (HFD). EGCG significantly inhibited the increase in histological fatty deposit and triglyceride accumulation in the liver induced by HFD, and improved intestinal dysbiosis. One of important findings is that the abundance of Proteobacteria and Defferibacteres phylums increased markedly in the HFD group, and this increase was significantly suppressed in the EGCG group. Interestingly, taurine-conjugated cholic acid (TCA) increased in the HFD group, like the mirror image against a marked decrease in the cholic acid (CA) value, and this increase was markedly inhibited in the EGCG group. TCA is not a simple serum biomarker for liver injury but TCA may be a causal factor to disturb lipid metabolism. The distribution of correlation coefficients by Heatmap analysis showed that the abundance of Akkermansia and Parabacteroides genus showed a positive correlation with CA and a negative correlation with TCA, and significantly increased in the EGCG group as compared with the HFD group. In addition, nutrigenomics approaches demonstrated that sirtuin signaling, EIF2 pathway and circadian clock are involved in the anti-steatotic effects of EGCG. In the present paper, we summarized recent update data of EGCG function focusing on intestinal microbiota and their interaction with host cells.

Effects of green tea or green tea catechin on liver enzymes in healthy individuals and people with nonalcoholic fatty liver disease: A systematic review and meta-analysis of randomized clinical trials

The therapeutic potential of green tea as a rich source of antioxidants and anti-inflammatory compounds has been investigated by several studies. The present study aimed to systematically review and analyze randomized clinical trials (RCTs) assessing the effects of green tea, catechin, and other forms of green tea supplementation on levels of liver enzymes. PubMed, SCOPUS, EMBASE, and Cochrane databases were searched until February 2019. All RCTs investigating the effect of green tea or its catechin on liver enzymes including alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bilirubin were included. A total of 15 RCTs were included. The overall effect of green tea on liver enzymes was nonsignificant (ALT [Standardized mean difference (SMD)= -0.17, CI -0.42 to 0.08, p = .19], AST [SMD = -0.07, CI -0.43 to 0.29, p = .69], and ALP [SMD = -0.17, CI -0.45 to 0.1, p = .22]). However, subgroup analyses showed that green tea reduced the levels of liver enzymes in participants with nonalcoholic fatty liver disease (NAFLD) but in healthy subjects, a small significant increase in liver enzymes was observed. In conclusion, the results of this study suggest that the effect of green tea on liver enzymes is dependent on the health status of individuals. While a moderate reducing effect was observed in patients with NAFLD, in healthy subjects, a small increasing effect was found.

Preventive Efficiency of Green Tea and Its Components on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a typical chronic liver disease highly correlated with metabolic syndrome. Growing prevalence of NAFLD is supposed to be linked with the unhealthy lifestyle, especially high-calorie diet and lacking enough exercise. Currently, there is no validated pharmacological therapy for NAFLD except for weight reduction. However, many dietary strategies had preventive effects on the development of liver steatosis or its progression. As one of the most common beverages, green tea contains abundant bioactive compounds possessing antioxidant, lipid-lowering, and anti-inflammatory effects, as well as improving insulin resistance and gut dysbiosis that can alleviate the risk of NAFLD. Hence, in this review, we summarized the studies of green tea and its components on NAFLD from animal experiments and human interventions and discussed the potential mechanisms. Available evidence suggested that tea consumption is promising to prevent NAFLD, and further mechanisms and clinical studies need to be investigated.

Flavanols are potential anti-obesity agents, a systematic review and meta-analysis of controlled clinical trials

BACKGROUND

The anti-obesity potential of flavonoids has been shown by animal and human studies. In this meta-analysis, we systematically reviewed controlled clinical trials and quantified the effects of flavonoids and flavonoid subclasses on obesity-related anthropometric measures.

METHODS AND RESULTS

PubMed, EMBASE, Scopus, Web of Science, and ProQuest databases were searched to identify trials examining the effect of flavonoids on body mass index (BMI), waist circumference, and body fat percentage. Fifty eight trials passed the eligibility process. Analysis endpoints were calculated as the mean difference between baseline and post-treatment. Flavonoids were in subclasses of flavanols, flavonols, isoflavones, flavanones, anthocyanins, and proanthocyanidins. They were mostly in the form of supplements and dosages varying from 40 to 1300 mg/day. Among flavonoid subclasses, flavanols showed potential for decreasing BMI, in the overall population (mean difference (MD) = -0.28 kg/m², P = 0.04; n = 21) and in the subgroups of Asians (MD = -0.42 kg/m²; P = 0.046; n = 13), ages < 50 years (MD = -0.50 kg/m²; P = 0.008; n = 14), BMI ≥ 25 kg/m² (MD = -0.30 kg/m²; P = 0.049; n = 15), and at doses ≥ 500 mg/day (MD = -0.36 kg/m²; P = 0.049; n = 12). Isoflavones also decreased BMI of non-Asian populations (MD = -0.26 kg/m²; P = 0.035; n = 13) and doses ≥ 75 mg/day (MD = -0.34 kg/m²; P = 0.027; n = 8). In the overall assessment, flavanols also decreased waist circumference (MD = -0.60 cm; P = 0.02; n = 18) but had no significant effect on body fat percentage. The available trials did not reveal significant effects from flavonols, flavanones, and anthocyanins on the specified anthropometric measures.

CONCLUSIONS

Overall results of this meta-analysis showed that flavanols have potential against obesity.

Green tea as a safe alternative approach for nonalcoholic fatty liver treatment: A systematic review and meta-analysis of clinical trials

This study aimed to evaluate the efficacy of green tea supplementation on nonalcoholic fatty liver disease treatment. Electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar, were systematically searched up to October 30, 2017, to identify eligible trials based on the inclusion criteria. The effect size was presented as mean difference with 95% confidence intervals (CI). The meta-analysis of data from four studies indicated significant effects of green tea supplementation in altering alanine aminotransferases (-12.81 U/L; 95% CI: -18.17 to -7.45) and aspartate aminotransferases (-10.91 U/L; 95% CI: -19.66 to -2.17) blood concentrations. Likewise, a favorable effect of green tea administration was observed on body mass index (-2.08 kg/cm² ; 95% CI: -2.81 to -1.36), triacylglycerol (-31.87 mg/dl; 95% CI: -40.62 to -23.12), total cholesterol (-27.57 mg/dl; 95% CI: -36.17 to -18.98), and low-density lipoprotein cholesterol (-14.15 mg/dl; 95% CI: -23.69 to -4.60), whereas no significant effect was detected on high-density lipoprotein cholesterol concentrations (7.41 mg/dl; 95% CI: -1.49 to 16.30) and homeostasis model assessment of insulin resistance (-4.06; 95% CI: -10.22 to 2.09). This systematic review and meta-analysis of available trials suggests that there  are potential benefits of green tea supplementation on nonalcoholic fatty liver disease.

Scientific opinion on the safety of green tea catechins

The EFSA ANS Panel was asked to provide a scientific opinion on the safety of green tea catechins from dietary sources including preparations such as food supplements and infusions. Green tea is produced from the leaves of Camellia sinensis (L.) Kuntze, without fermentation, which prevents the oxidation of polyphenolic components. Most of the polyphenols in green tea are catechins. The Panel considered the possible association between the consumption of (-)-epigallocatechin-3-gallate (EGCG), the most relevant catechin in green tea, and hepatotoxicity. This scientific opinion is based on published scientific literature, including interventional studies, monographs and reports by national and international authorities and data received following a public 'Call for data'. The mean daily intake of EGCG resulting from the consumption of green tea infusions ranges from 90 to 300 mg/day while exposure by high-level consumers is estimated to be up to 866 mg EGCG/day, in the adult population in the EU. Food supplements containing green tea catechins provide a daily dose of EGCG in the range of 5-1,000 mg/day, for adult population. The Panel concluded that catechins from green tea infusion, prepared in a traditional way, and reconstituted drinks with an equivalent composition to traditional green tea infusions, are in general considered to be safe according to the presumption of safety approach provided the intake corresponds to reported intakes in European Member States. However, rare cases of liver injury have been reported after consumption of green tea infusions, most probably due to an idiosyncratic reaction. Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.

The safety of green tea and green tea extract consumption in adults - Results of a systematic review

A systematic review of published toxicology and human intervention studies was performed to characterize potential hazards associated with consumption of green tea and its preparations. A review of toxicological evidence from laboratory studies revealed the liver as the target organ and hepatotoxicity as the critical effect, which was strongly associated with certain dosing conditions (e.g. bolus dose via gavage, fasting), and positively correlated with total catechin and epigallocatechingallate (EGCG) content. A review of adverse event (AE) data from 159 human intervention studies yielded findings consistent with toxicological evidence in that a limited range of concentrated, catechin-rich green tea preparations resulted in hepatic AEs in a dose-dependent manner when ingested in large bolus doses, but not when consumed as brewed tea or extracts in beverages or as part of food. Toxico- and pharmacokinetic evidence further suggests internal dose of catechins is a key determinant in the occurrence and severity of hepatotoxicity. A safe intake level of 338 mg EGCG/day for adults was derived from toxicological and human safety data for tea preparations ingested as a solid bolus dose. An Observed Safe Level (OSL) of 704 mg EGCG/day might be considered for tea preparations in beverage form based on human AE data.

Potential Biological Effects of (-)-Epigallocatechin-3-gallate on the Treatment of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a major health issue throughout the world. However, no validated treatments for NAFLD are currently available. In‐depth studies have demonstrated the efficacy of (‐)‐epigallocatechin‐3‐gallate (EGCG), a main bioactive chemical extracted from green tea, in treating NAFLD. EGCG exhibits multi‐pronged preventive and therapeutic activities, including promoting lipid and glucose metabolism, anti‐lipid peroxidation and anti‐inflammation activities, anti‐fibrosis, and anti‐NAFLD related tumor, thus contributing to the mitigation of NAFLD occurrence and progression. The objectives of this paper are to review and discuss the currently known targets, signaling pathways and roles of EGCG that interfere with NAFLD pathogenesis, then providing additional experimental evidence and the foundation for the further studies and clinical applications of EGCG in the prevention and treatment of NAFLD.

The Impact of Green Tea Supplementation on Anthropometric Indices and Inflammatory Cytokines in Women with Polycystic Ovary Syndrome

The present study aimed to determine the effect of a green tea supplement on anthropometric indices and inflammatory factors in women with polycystic ovary syndrome (PCOS). In this randomized clinical trial, 45 women with PCOS were randomly allocated into two groups receiving green tea tablets or placebo. The period of intervention was 45 days. The serum levels of interleukin 6, high-sensitivity C-reactive protein, and tumor necrosis factor α were measured before and after intervention period using the related kits. Anthropometric indices also were measured. The mean of body mass index, weight, waist circumference, and body fat percentage in the green tea group were reduced significantly. However, no significant difference was observed between the two groups. Also, there was no significant effect on the levels of inflammatory factors. The present results suggest that daily consumption of green tea tablets did not cause any effect on inflammation biomarkers in PCOS women. However, it may be effective as a complementary treatment for weight control in these women. Copyright © 2017 John Wiley & Sons, Ltd.

Green tea extract attenuates CCl4-induced hepatic injury in male hamsters via inhibition of lipid peroxidation and p53-mediated apoptosis

Keeping in mind the beneficial effects of GTE administration on liver damage, the present study was undertaken to evaluate the hepatoprotective effect of green tea extract (GTE) against carbon tetrachloride (CCl4)-induced liver injuries in male hamsters for 8 weeks. Twenty hamsters were equally divided into 4 groups, the control ones (group I) received only dis. water. Hamsters of group II had free access to 10% of GTE, while hamsters of group III received 1 ml/kg of 50% CCl4 in corn oil via gavage daily. Hamsters of group IV (GTE + CCl4) received a free access to GTE supplementation in combination with 1 ml/kg of 50% CCl4 in corn oil via gavage daily. Lipid profile, hepatic enzyme levels and apoptosis molecular marker (p53) were investigated in hamsters. GTE + CCl4 treated hamsters showed lower levels of hepatic malondialdehyde (MDA) than CCl4 exposed hamsters. Hepatic activity levels of GSH, ALD and cytochrome 450 reductase were declined after CCl4 administration while they were remarkably improved with GTE administration. Serum lipid profiles as T-cholesterol (TC), triglyceride (TG) and low density lipoproteins (LDL) were improved in GTE and CCl4 treated hamsters than CCl4 group. Moreover, hepatic tissue damage and p53 expression induced with CCl4 were improved with the treatment of GTE. These results suggested that GTE possesses hepatoprotective properties against the effect of CCl4.

Green tea extract improves the oxidative state of the liver and brain in rats with adjuvant-induced arthritis

The purpose of the study was to evaluate the possible effects of the administration of a green tea extract on the oxidative state of the liver and brain of adjuvant-induced arthritic rats, a model for human rheumatoid arthritis. Daily doses of 250 mg kg(-1) (59.8 mg catechins per kg) for 23 days were administered. This treatment produced significant diminutions in protein and lipid damage in liver, brain and plasma. It also diminished the tissue ROS contents and increased the antioxidant capacity of the plasma. The antioxidant defenses, which are diminished by arthritis, were improved by the green tea treatment, as revealed by the restoration of the GSH and protein thiol levels and by the strong tendency for normalizing the activities of the antioxidant enzymes. The activity of glucose 6-phosphate dehydrogenase, which is increased by arthritis in the liver, was also almost normalized by the treatment. In conclusion, it can be said that green tea consumption is possibly beneficial for the liver and brain of patients suffering from rheumatoid arthritis because it attenuates the pronounced oxidative stress that accompanies the disease and, thus, diminishes the injury to lipids and proteins in both liver and brain. There are also indications that, in the liver, the green tea can contribute to normalize the metabolic functions that are substantially modified by arthritis. For example, the green tea normalized the activity of glucose 6-phosphate dehydrogenase, a key enzyme of an important metabolic route (pentose monophosphate pathway). It is expected that the green tea treatment is equally able to normalize the activity of other enzymes (e.g., glucokinase and glucose 6-phosphatase), a hypothesis to be tested by future work.