Novel insights of dietary polyphenols and obesity.

The prevalence of obesity has steadily increased over the past three decades both in the United States and worldwide. Recent studies have shown the role of dietary polyphenols in the prevention of obesity and obesity-related chronic diseases. Here, we evaluated the impact of commonly consumed polyphenols, including green tea catechins, especially epigallocatechin gallates, resveratrol and curcumin, on obesity and obesity-related inflammation. Cellular studies demonstrated that these dietary polyphenols reduce viability of adipocytes and proliferation of preadipocytes, suppress adipocyte differentiation and triglyceride accumulation, stimulate lipolysis and fatty acid β-oxidation, and reduce inflammation. Concomitantly, the polyphenols modulate signaling pathways including the adenosine-monophosphate-activated protein kinase, peroxisome proliferator activated receptor γ, CCAAT/enhancer binding protein α, peroxisome proliferator activator receptor gamma activator 1-alpha, sirtuin 1, sterol regulatory element binding protein-1c, uncoupling proteins 1 and 2, and nuclear factor-κB that regulate adipogenesis, antioxidant and anti-inflammatory responses. Animal studies strongly suggest that commonly consumed polyphenols described in this review have a pronounced effect on obesity as shown by lower body weight, fat mass and triglycerides through enhancing energy expenditure and fat utilization, and modulating glucose hemostasis. Limited human studies have been conducted in this area and are inconsistent about the antiobesity impact of dietary polyphenols probably due to the various study designs and lengths, variation among subjects (age, gender, ethnicity), chemical forms of the dietary polyphenols used and confounding factors such as other weight-reducing agents. Future randomized controlled trials are warranted to reconcile the discrepancies between preclinical efficacies and inconclusive clinic outcomes of these polyphenols.

Wang S ，Moustaid-Moussa N ，Chen L ，Mo H ，Shastri A ，Su R ，Bapat P ，Kwun I ，Shen CL ... -  《-》

Effect of Korean Red Ginseng on metabolic syndrome.

Metabolic syndrome (MS) refers to a clustering of at least three of the following medical conditions: high blood pressure, abdominal obesity, hyperglycemia, low high-density lipoprotein level, and high serum triglycerides. MS is related to a wide range of diseases which includes obesity, diabetes, insulin resistance, cardiovascular disease, dyslipidemia, or non-alcoholic fatty liver disease. There remains an ongoing need for improved treatment strategies for MS. The most important risk factors are dietary pattern, genetics, old age, lack of exercise, disrupted biology, medication usage, and excessive alcohol consumption, but pathophysiology of MS has not been completely identified. Korean Red Ginseng (KRG) refers to steamed/dried ginseng, traditionally associated with beneficial effects such as anti-inflammation, anti-fatigue, anti-obesity, anti-oxidant, and anti-cancer effects. KRG has been often used in traditional medicine to treat multiple metabolic conditions. This paper summarizes the effects of KRG in MS and related diseases such as obesity, cardiovascular disease, insulin resistance, diabetes, dyslipidemia, or non-alcoholic fatty liver disease based on experimental research and clinical studies.

Yoon SJ ，Kim SK ，Lee NY ，Choi YR ，Kim HS ，Gupta H ，Youn GS ，Sung H ，Shin MJ ，Suk KT ... -  《-》

Clinical efficacies, underlying mechanisms and molecular targets of Chinese medicines for diabetic nephropathy treatment and management.

Diabetic nephropathy (DN) has been recognized as a severe complication of diabetes mellitus and a dominant pathogeny of end-stage kidney disease, which causes serious health problems and great financial burden to human society worldwide. Conventional strategies, such as renin-angiotensin-aldosterone system blockade, blood glucose level control, and bodyweight reduction, may not achieve satisfactory outcomes in many clinical practices for DN management. Notably, due to the multi-target function, Chinese medicine possesses promising clinical benefits as primary or alternative therapies for DN treatment. Increasing studies have emphasized identifying bioactive compounds and molecular mechanisms of reno-protective effects of Chinese medicines. Signaling pathways involved in glucose/lipid metabolism regulation, antioxidation, anti-inflammation, anti-fibrosis, and podocyte protection have been identified as crucial mechanisms of action. Herein, we summarize the clinical efficacies of Chinese medicines and their bioactive components in treating and managing DN after reviewing the results demonstrated in clinical trials, systematic reviews, and meta-analyses, with a thorough discussion on the relative underlying mechanisms and molecular targets reported in animal and cellular experiments. We aim to provide comprehensive insights into the protective effects of Chinese medicines against DN.

Tang G ，Li S ，Zhang C ，Chen H ，Wang N ，Feng Y ... -  《-》

Green tea (-)-epigallocatechin-3-gallate reduces body weight with regulation of multiple genes expression in adipose tissue of diet-induced obese mice.

The aim of this study was to investigate the antiobesity effect of (-)-epigallocatechin-3-gallate (EGCG) in diet-induced obese mice. Male C57BL/6J mice were fed on a high-fat diet for 8 weeks to induce obesity. Subsequently they were divided into 3 groups and were maintained on a high-fat control diet or high-fat diets supplemented with 0.2 or 0.5% EGCG (w/w) for a further 8 weeks. Changes in the expression of genes related to lipid metabolism and fatty acid oxidation were analyzed in white adipose tissue, together with biometric and blood parameters. Experimental diets supplemented with EGCG resulted in reduction of body weight and mass of various adipose tissues in a dose-dependent manner. EGCG diet also considerably lowered the levels of plasma triglyceride and liver lipid. In the epididymal white adipose tissue of EGCG diet-fed mice, the mRNA levels of adipogenic genes such as peroxisome proliferator-activated receptor-gamma (PPAR-gamma), CCAAT enhancer-binding protein-alpha (C/EBP-alpha), regulatory element-binding protein-1c (SREBP-1c), adipocyte fatty acid-binding protein (aP2), lipoprotein lipase (LPL) and fatty acid synthase (FAS) were significantly decreased. However, the mRNA levels of carnitine palmitoyl transferase-1 (CPT-1) and uncoupling protein 2 (UCP2), as well as lipolytic genes such as hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), were significantly increased. These results suggest that green tea EGCG effectively reduces adipose tissue mass and ameliorates plasma lipid profiles in high-fat diet-induced obese mice. These effects might be at least partially mediated via regulation of the expression of multiple genes involved in adipogenesis, lipolysis, beta-oxidation and thermogenesis in white adipose tissue.

Lee MS ，Kim CT ，Kim Y 《-》

Methionine restriction prevents the progression of hepatic steatosis in leptin-deficient obese mice.

This study investigated the effects of dietary methionine restriction (MR) on the progression of established hepatic steatosis in the leptin-deficient ob/ob mouse. Ten-week-old ob/ob mice were fed diets containing 0.86% (control-fed; CF) or 0.12% methionine (MR) for 14 weeks. At 14 weeks, liver and fat were excised and blood was collected for analysis. In another study, blood was collected to determine in vivo triglyceride (TG) and very-low-density lipoprotein (VLDL) secretion rates. Liver histology was conducted to determine the severity of steatosis. Hepatic TG, free fatty acid levels, and fatty acid oxidation (FAO) were also measured. Gene expression was analyzed by quantitative PCR. MR reversed the severity of steatosis in the ob/ob mouse. This was accompanied by reduced body weight despite similar weight-specific food intake. Compared with the CF group, hepatic TG levels were significantly reduced in response to MR, but adipose tissue weight was not decreased. MR reduced insulin and HOMA ratios but increased total and high-molecular-weight adiponectin levels. Scd1 gene expression was significantly downregulated, while Acadvl, Hadha, and Hadhb were upregulated in MR, corresponding with increased β-hydroxybutyrate levels and a trend toward increased FAO. The VLDL secretion rate was also significantly increased in the MR mice, as were the mRNA levels of ApoB and Mttp. The expression of inflammatory markers, such as Tnf-α and Ccr2, was also downregulated by MR. Our data indicate that MR reverses steatosis in the ob/ob mouse liver by promoting FAO, increasing the export of lipids, and reducing obesity-related inflammatory responses.

Malloy VL ，Perrone CE ，Mattocks DA ，Ables GP ，Caliendo NS ，Orentreich DS ，Orentreich N ... -  《-》