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.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/mnfr.201700483

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

Fu brick tea (FBT) is a microbial-fermented tea, which is produced by the solid-state fermentation of tea leaves. Previous studies have proved that FBT aqueous extracts could attenuate obesity and gut microbiota dysbiosis. However, the bioactive components in FBT that contribute to these activities remain unclear. In this study, we aimed to investigate the effects of FBT polyphenols (FBTPs) on obesity, gut microbiota, and gut microbiota-related intestinal oxidative stress and barrier function and to further investigate whether the antiobesity effect of FBTPs was dependent on the alteration of gut microbiota. The results showed that FBTP supplementation effectively attenuated obesity in high-fat diet (HFD)-fed rats. FBTP supplementation improved the intestinal oxidative stress and intestinal barrier function, including intestinal inflammation and the integrity of the intestinal barrier. Furthermore, FBTP intervention significantly attenuated HFD-induced gut microbiota dysbiosis, characterized by increased phylogenetic diversity and decreased Firmicutes/Bacteroidetes ratio. Certain core microbes, including Akkermansia muciniphila, Alloprevotella, Bacteroides, and Faecalibaculum, were also found to be improved by FBTPs. Moreover, the antiobesity effect of FBTPs was gut microbiota-dependent, as demonstrated by a fecal microbiota transplantation experiment. Collectively, we concluded that FBTPs reduced obesity by modulating the gut microbiota and gut microbiota-related intestinal oxidative stress and barrier function. Therefore, FBTPs may be used as prebiotic agents to treat obesity and gut microbiota dysbiosis in obese individuals.

Polyphenols from Fu Brick Tea Reduce Obesity via Modulation of Gut Microbiota and Gut Microbiota-Related Intestinal Oxidative Stress and Barrier Function.

Natural alkaloid and polyphenol compounds targeting lipid metabolism: Treatment implications in metabolic diseases.

To identify differentially expressed hepatic genes contributing to the improvement of high-fat (HF) diet-induced hepatic steatosis and insulin resistance following supplementation of partially defatted flavonoid-rich Chardonnay grape seed flour (ChrSd), diet-induced obese (DIO) mice were fed HF diets containing either ChrSd or microcrystalline cellulose (MCC, control) for 5 weeks. The 2-h insulin area under the curve was significantly lowered by ChrSd, indicating that ChrSd improved insulin sensitivity. ChrSd intake also significantly reduced body weight gain, liver and adipose tissue weight, hepatic lipid content, and plasma low-density lipoprotein (LDL)-cholesterol, despite a significant increase in food intake. Exon microarray analysis of hepatic gene expression revealed down-regulation of genes related to triglyceride and ceramide synthesis, immune response, oxidative stress, and inflammation and upregulation of genes related to fatty acid oxidation, cholesterol, and bile acid synthesis. In conclusion, the effects of ChrSd supplementation in a HF diet on weight gain, insulin resistance, and progression of hepatic steatosis in DIO mice were associated with modulation of hepatic genes related to oxidative stress, inflammation, ceramide synthesis, and lipid and cholesterol metabolism.

/pdf/chardonnay-grape-seed-flour-ameliorates-hepatic-steatosis-59vshhh0vo.pdf

Chardonnay Grape Seed Flour Ameliorates Hepatic Steatosis and Insulin Resistance via Altered Hepatic Gene Expression for Oxidative Stress, Inflammation, and Lipid and Ceramide Synthesis in Diet-Induced Obese Mice

Salacia reticulata Wight (S. reticulata) is a herbal medicine used for treatment of early diabetes in Ayurvedic medicine. In previous reports, the extract of S. reticulata showed preventive effects on obesity and various metabolic disorders and a suppressive effect on differentiation in premature adipocytes. The aim of this research was to elucidate the therapeutic efficacy of the extract of S. reticulata on obesity and various metabolic disorders in 12-week-old TSOD mice with obesity and metabolic disorders and in mature 3T3-L1 adipocytes. In TSOD mice, S. reticulata therapy produced a reduction in body weight and mesenteric fat accumulation, an improvement in abnormal glucose metabolism, and an increase in adiponectin level in plasma. In addition, the mRNA expressions of hormone-sensitive lipase (HSL) and adiponectin were increased in mesenteric fat. In in vitro experiments, S. reticulata therapy produced suppression of intracellular triacylglycerol accumulation and enhancement of glycerol release into the medium in mature 3T3-L1 cells. The mRNA expressions of lipogenesis factor (peroxisome proliferator-activated receptor γ, lipoprotein lipase, CD36, and fatty acid binding protein 4) were down-regulated, while the expressions of lipolysis factor (adipose tissue triacylglycerol lipase and HSL) and adiponectin were up-regulated. Moreover, the extract of S. reticulata enhanced the expression of total AMP-activated protein kinase α (AMPKα) and phosphorylated AMPKα in mature adipocytes. These findings demonstrate that the extract of S. reticulata has therapeutic effects on obesity and metabolic disorders by enhancing lipogenesis genes and suppressing lipolysis genes through the activation of AMPKα in adipocytes.

Salacia reticulata has therapeutic effects on obesity

Background
(−)-Epigallocatechin-3-gallate (EGCG), the most abundant catechin found in green tea, effectively reduces body weight and tissue and blood lipid accumulation. To explore the mechanism by which EGCG inhibits cellular lipid accumulation in free fatty acid (FFA) induced HepG2 cell culture, we investigated the proteome change of FFA-induced HepG2 cells exposed to EGCG using two-dimensional gel electrophoresis and mass spectrometry.

/pdf/proteomic-analysis-of-the-inhibitory-effect-of-cnnvxjt7dz.pdf

Proteomic analysis of the inhibitory effect of epigallocatechin gallate on lipid accumulation in human HepG2 cells

Purple-leaf tea cultivars are known for their specific chemical composition that greatly influences tea bioactivity and plant resistance. Some studies have tried to reveal the purple-leaf formation mechanism of tea by comparing the purple new leaves and green older leaves in the same purple-leaf tea cultivar. It has been reported that almost all structural genes involved in anthocyanin/flavonoid biosynthesis were down-regulated in purple-leaf tea cultivars when the purple new leaves become green older leaves. However, anthocyanin/flavonoid biosynthesis is also affected by the growth period of tea leaves, gradually decreasing as new tea leaves become old tea leaves. This leads to uncertainty as to whether the purple-leaf formation is attributed to the high expression of structural genes in anthocyanin/flavonoid biosynthesis. To better understand the mechanisms underlying purple-leaf formation, we analyzed the biosynthesis of three pigments (chlorophylls, carotenoids, and anthocyanins/flavonoids) by integrated metabolic and gene expression analyses in four purple-leaf tea cultivars including Camellia sinensis var. sinensis and var. assamica. Green-leaf and yellow-leaf cultivars were employed for comparison. The purple-leaf phenotype was mainly attributed to high anthocyanins and low chlorophylls. The purple-leaf phenotype led to other flavonoid changes including lowered monomeric catechin derivatives and elevated polymerized catechin derivatives. Gene expression analysis revealed that 4-coumarate: CoA ligase (4CL), anthocyanidin synthase (ANS), and UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT) genes in the anthocyanin biosynthetic pathway and the uroporphyrinogen decarboxylase (HEME) gene in the chlorophyll biosynthetic pathway were responsible for high anthocyanin and low chlorophyll, respectively. These findings provide insights into the mechanism of purple-leaf formation in tea cultivars.

/pdf/metabolic-profiling-and-gene-expression-analyses-of-purple-m3mog2gkt7.pdf

Bin Tan

Papers

Proteomic analysis of the inhibitory effect of epigallocatechin gallate on lipid accumulation in human HepG2 cells

Metabolic Profiling and Gene Expression Analyses of Purple-Leaf Formation in Tea Cultivars (Camellia sinensis var. sinensis and var. assamica).