Diosgenin present in fenugreek improves glucose metabolism by promoting adipocyte differentiation and inhibiting inflammation in adipose tissues

In obesity, adipocyte hypertrophy and chronic inflammation in adipose tissues cause insulin resistance and type‐2 diabetes. Trigonella foenum‐graecum (fenugreek) can ameliorate hyperglycemia and diabetes. However, the effects of fenugreek on adipocyte size and inflammation in adipose tissues have not been demonstrated. In this study, we determined the effects of fenugreek on adipocyte size and inflammation in adipose tissues in diabetic obese KK‐Ay mice, and identified the active substance in fenugreek. Treatment of KK‐Ay mice with a high fat diet supplemented with 2% fenugreek ameliorated diabetes. Moreover, fenugreek miniaturized the adipocytes and increased the mRNA expression levels of differentiation‐related genes in adipose tissues. Fenugreek also inhibited macrophage infiltration into adipose tissues and decreased the mRNA expression levels of inflammatory genes. In addition, we identified diosgenin, a major aglycone of saponins in fenugreek to promote adipocyte differentiation and to inhibit expressions of several molecular candidates associated with inflammation in 3T3‐L1 cells. These results suggest that fenugreek ameliorated diabetes by promoting adipocyte differentiation and inhibiting inflammation in adipose tissues, and its effects are mediated by diosgenin. Fenugreek containing diosgenin may be useful for ameliorating the glucose metabolic disorder associated with obesity.     

Anti‐inflammatory Potential of Quercetin‐3‐O‐β‐D‐(“2”‐galloyl)‐glucopyranoside and Quercetin Isolated from Diospyros kaki calyx via Suppression of MAP Signaling Molecules in LPS‐induced RAW 264.7 Macrophages

Diospyros kaki (DK) contains an abundance of flavonoids and has been used in folk medicine in Korea for centuries. Here, we report for the first time the anti‐inflammatory activities of Quercetin (QCT) and Quercetin 3‐O‐β‐(“2”‐galloyl)‐glucopyranoside (Q32G) isolated from DK. We have determine the no cytotoxicity of Q32G and QCT against RAW 264.7 cells up to concentration of 50 μM. QCT and Q32G demonstrated potent anti‐inflammatory activities by reducing expression of nitric oxide (NO), tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6 inducible NO synthase (iNOS), cyclooxygenase (COX)‐2, and mitogen‐activated protein kinase (MAPKs) in mouse RAW 264.7 macrophages activated with lipopolysaccharide (LPS). Both QCT or Q32G could decrease cellular protein levels of COX‐2 and iNOS as well as secreted protein levels of NO, PGE₂, and cytokines (TNF‐α, IL‐1β, and IL‐6) in culture medium of LPS‐stimulated RAW 264.7 macrophages. Immunoblot analysis showed that QCT and Q32G suppressed LPS‐induced MAP kinase pathway proteins p‐p38, ERK, and JNK. This study revealed that QCT and Q32G have anti‐inflammatory potential, however Q32G possess comparable activity as that of QCT and could be use as adjuvant to treat inflammatory diseases.     

Cinnamomum camphora Seed Kernel Oil Ameliorates Oxidative Stress and Inflammation in Diet‐Induced Obese Rats

Cinnamomum camphora seed kernel oil (CCSKO) was found to reduce body fat deposition and improve blood lipid in both healthy and obese rats. The study was aimed to investigate the antioxidative stress and anti‐inflammatory effects of CCSKO in high‐fat‐diet‐induced obese rats. The obese rats were treated with CCSKO, lard, and soybean oil, respectively, for 12 wk. The level of total antioxidant capacity (T‐AOC), activities of superoxide dismutase (SOD), glutathione peroxidase, and catalase, and levels of malondialdehyde (MDA), tumor necrosis factor (TNF)‐α, peroxisome proliferator‐activated receptor (PPAR)‐γ, interleukin (IL)‐6, and P65 were compared among CCSKO, lard, and soybean oil groups. Our results showed that the level of T‐AOC and activities of SOD and catalase were significantly increased and the level of MDA was significantly decreased in CCSKO group. In addition, CCSKO treatment reduced the activities of serum glutamic oxaloacetic transaminase and glutamate‐pyruvate transaminase, and levels of serum TNF‐α, IL‐6, and P65 through raising the level of PPAR‐γ. In conclusion, CCSKO has, for the first time, been found to ameliorate oxidative stress and inflammation in high‐fat‐diet‐induced obese rats.     

Polygonum viviparum L. inhibits the lipopolysaccharide‐induced inflammatory response in RAW264.7 macrophages through haem oxygenase‐1 induction and activation of the Nrf2 pathway

BACKGROUND: Polygonum viviparum L. (PV) is a member of the family Polygonaceae and is widely distributed in high‐elevation areas. It is used as a folk remedy to treat inflammation‐related diseases. This study was focused on the anti‐inflammatory response of PV against lipopolysaccharide (LPS)‐induced inflammation in RAW264.7 macrophages. RESULTS: Treatment with PV did not cause cytotoxicity at 0–50 µg mL^?1 in RAW264.7 macrophages, and the IC₅₀ value was 270 µg mL^?1. PV inhibited LPS‐stimulated nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)‐1β and tumour necrosis factor (TNF)‐α release and inducible NO synthase (iNOS) and cyclooxygenase (COX)‐2 protein expression. In addition, PV suppressed the LPS‐induced p65 expression of nuclear factor (NF)‐κB, which is associated with the inhibition of IκB‐α degradation. These results suggest that, among mechanisms of the anti‐inflammatory response, PV inhibits the production of NO and these cytokines by down‐regulating iNOS and COX‐2 gene expression. Furthermore, PV can induce haem oxygenase (HO)‐1 protein expression through nuclear factor E2‐related factor 2 (Nrf2) activation. A specific inhibitor of HO‐1, zinc(II) protoporphyrin IX, inhibited the suppression of iNOS and COX‐2 expression by PV. CONCLUSION: These results suggest that PV possesses anti‐inflammatory actions in macrophages and works through a novel mechanism involving Nrf2 actions and HO‐1. Thus PV could be considered for application as a potential therapeutic approach for inflammation‐associated disorders. © 2012 Society of Chemical Industry     

The probiotic Lactobacillus rhamnosus BFE5264 and Lactobacillus plantarum NR74 promote cholesterol efflux and suppress inflammation in THP‐1 cells

BACKGROUND: The balance between the rate of cholesterol uptake/accumulation and the rate of cholesterol efflux is reflected in the amount of lipid accumulation in macrophages. Based upon the fact that liver X receptors (LXRs) play a role in cholesterol efflux, we studied the effects of probiotics on cholesterol efflux and anti‐inflammatory action in macrophages. We confirmed changes in LXR expression by treatment of LXR‐transfected CHO‐K1 cells with lactic acid bacteria (LAB), and co‐cultured THP‐1 cells with LAB to investigate changes in cholesterol efflux and inflammation. RESULTS: The experiment with CHO‐K1 cells showed upregulation of LXR‐β by LAB. Treatment of THP‐1 cells with LAB promoted LXR expression in THP‐1, which eventually led to significant upregulation of ABCA1 and ABCG1 expression. The treatment with live LAB also significantly promoted cholesterol efflux. LAB suppressed expression of interleukin (IL)‐1β and tumor necrosis factor (TNF)‐α, which resulted from activation of LXR. CONCLUSION: Our study shows that Lactobacillus rhamnosus BFE5264 and Lactobacillus plantarum NR74 activated LXR and induced cholesterol efflux by promoting expression of ABCA1 and ABCG1. Both strains also suppressed proinflammatory cytokines including IL‐1β and TNF‐α. This study could account for the observation that LAB may block foam cell formation by cholesterol efflux and immune modulation. © 2012 Society of Chemical Industry     

Characterization,Anti‐Inflammatory and Antiproliferative Activities of Natural and Sulfonated Exo‐Polysaccharides from Streptococcus thermophilus ASCC 1275

Exo‐polysaccharides (EPS) isolated from Streptococcus thermophilus ASCC 1275 were sulfated (31%). High‐performance liquid chromatography identified that EPS was composed of mannose (30.19%), galactose (20.10%), glucose (18.05%), glucosamine (16.04%), galactosamine (9.06%), glucuronic acid (3.55%), and ribose (3.01%). Pro‐/anti‐inflammatory cytokine secretion ratios (IL‐1β/IL‐10, IL‐6/IL‐10, and TNF‐α/IL‐10) of lipopolysaccharide stimulated RAW 264.7 macrophages were significantly decreased by EPS and S.EPS treatments in a dose dependent manner. Furthermore, anti‐inflammatory activities of S.EPS improved 49.3% and 24.0% than those of EPS before or after LPS treatment. The reactive oxygen species were inhibited by EPS and S.EPS by 49.6% and 55.1% at 50 μg/mL, respectively. Inhibition activities of S.EPS on nitric oxide production were 12.9% and 55.4% higher than those of EPS at 10 and 50 μg/mL. Additionally, S.EPS exhibited stronger antiproliferative activity on Caco‐2 and HepG2 cells. Our results indicated that anti‐inflammatory and antiproliferative activities of EPS were significantly (P < 0.01) improved by sulfonation.     

c9t11‐Conjugated linoleic acid‐rich oil fails to attenuate wasting in colon‐26 tumor‐induced late‐stage cancer cachexia in male CD2F1 mice

Scope: Cancer cachexia is characterized by muscle and adipose tissue wasting caused partly by chronic, systemic inflammation. Conjugated linoleic acids (CLAs) are a group of fatty acids with various properties including anti‐inflammatory cis9, trans11 (c9t11)‐CLA and lipid‐mobilizing trans10, cis12 (t10c12)‐CLA. The purpose of this study was to test whether dietary supplementation of a c9t11‐CLA‐rich oil (6:1 c9t11:t10c12) could attenuate wasting of muscle and adipose tissue in colon‐26 adenocarcinoma‐induced cachexia in mice. Methods and results: Loss of body weight, muscle and adipose tissue mass caused by tumors were not rescued by supplementation with the c9t11‐CLA‐rich oil. In quadriceps muscle, c9t11‐CLA‐rich oil exacerbated tumor‐induced gene expression of inflammatory markers tumor necrosis factor‐α, IL‐6 receptor and the E3 ligase MuRF‐1 involved in muscle proteolysis. In epididymal adipose tissue, tumor‐driven delipidation and atrophy was aggravated by the c9,t11‐CLA‐rich oil, demonstrated by further reduced adipocyte size and lower adiponectin expression. However, expression of inflammatory cytokines and macrophage markers were not altered by tumors, or CLA supplementation. Conclusion: These data suggest that addition of c9t11‐CLA‐rich oil (0.6% c9t11, 0.1% t10c12) in diet did not ameliorate wasting in mice with cancer cachexia. Instead, it increased expression of inflammatory markers in the muscle and increased adipose delipidation.     

Immuno‐Resolving Ability of Resolvins,Protectins, and Maresins Derived from Omega‐3 Fatty Acids in Metabolic Syndrome

Omega‐3 fatty acid consumption has been suggested to be beneficial for the prevention of type 2 diabetes mellitus (T2DM). Its effects have been attributed to anti‐inflammatory activity, with the inhibition of arachidonic acid metabolism playing a central role. However, a more recent view is that omega‐3 fatty acids play an active role as the precursors of potent, specialized pro‐resolving mediators (SPMs), such as resolvins, protectins, and maresins. Docosahexaenoic acid (DHA)‐ and eicosapentaenoic‐acid‐derived SPMs are identified in the adipose tissue but the levels of certain SPMs (e.g., protectin D1) are markedly reduced with obesity, suggesting adipose SPM deficiency, potentially resulting in unresolved inflammation. Supplementation of the biosynthetic intermediates of SPM (e.g., 17‐hydroxy‐DHA) or omega‐3 fatty acids increases the level of adipose SPMs, reduces adipose inflammation (decrease in macrophage accumulation and change to less inflammatory macrophages), and enhances insulin sensitivity. The findings from studies using rodent obesity models must be translated to humans. It will be important to further elucidate the underlying mechanisms by which obesity reduces the levels of and the sensitivity to SPM in adipose tissues. This will enable the development of nutrition therapy to enhance the effects of omega‐3 fatty acids in the prevention and/or treatment of T2DM.     

Anti‐glycative and anti‐inflammatory effects of caffeic acid and ellagic acid in kidney of diabetic mice

Protective effects of caffeic acid (CA) and ellagic acid (EA) in kidney of diabetic mice were examined. CA or EA at 2.5 and 5% was mixed in diet and supplied to diabetic mice for 12 wk. Results showed that the intake of CA or EA increased renal content of these compounds, alleviated body weight loss, decreased urine output, increased plasma insulin and decreased blood glucose levels at weeks 6 and 12 (p<0.05). The intake of these compounds dose dependently reduced plasma blood urea nitrogen and elevated creatinine clearance (p<0.05). CA or EA at 5% significantly decreased the levels of plasma HbA1c, urinary glycated albumin, renal carboxymethyllysine, pentosidine, sorbitol and fructose (p<0.05), and significantly diminished renal activity of aldose reductase and sorbitol dehydrogenase, as well as suppressed renal aldose reductase mRNA expression (p<0.05). CA or EA dose dependently lowered renal levels of IL‐6, IL‐1β, tumor necrosis factor (TNF)‐α and monocyte chemoattractant protein 1 (MCP‐1) (p<0.05). Furthermore, CA or EA dose dependently down‐regulated tumor necrosis factor‐α and monocyte chemoattractant protein‐1 mRNA expression in kidney (p<0.05). Based on the observed anti‐glycative and anti‐inflammatory effects, the supplement of CA or EA might be helpful for the prevention or attenuation of diabetic kidney diseases.     

Vitamin B6 suppresses serine protease inhibitor 3 expression in the colon of rats and in TNF-α-stimulated HT-29 cells

Scope: Previous reports in the areas of animal studies and, recently epidemiology, have linked anti‐tumorigenic and anti‐inflammatory effects to dietary vitamin B6. This study investigated the molecular mechanism of these effects of vitamin B6. Methods and results: DNA microarray analysis was used to obtain information on changes in colon gene expression from vitamin B6 (pyridoxine) repletion in vitamin B6‐deficient rats. Pyridoxine supplementation down‐regulated the inflammatory molecule, serine protease inhibitor clade A member 3 (SPI‐3) mRNA expression in the colon. This study also showed that tumor necrosis factor α (TNF‐α) induced SPI‐3 mRNA expression in HT‐29 human colon cancer cells, and vitamin B6 (pyridoxal hydrochloride) pretreatment of HT‐29 cells inhibited TNF ‐induced mRNA expression of SPI‐3. Vitamin B6 inhibited TNF‐α‐induced NF‐κB activation via suppression of IκBα degradation in HT‐29 cells. HT‐29 cells stably expressing epitope‐tagged ubiquitin were generated and vitamin B6 pretreatment was shown to inhibit ubiquitination of the IkB protein in response to TNF‐α‐i. Conclusion: Vitamin B6 suppressed SPI‐3 expression in the colon of rats and in TNF‐α‐stimulated HT‐29 cells. Further, this study showed a possible role of vitamin B6 in the regulation of protein ubiquitination.     

铁观音茶提取物对脂多糖诱导RAW264.7细胞炎症反应的抑制作用及机制

研究铁观音茶提取物对脂多糖(LPS)诱导的RAW264.7细胞炎症反应的抑制作用及机制。用脂多糖作用于RAW264.7细胞,建立炎症模型,并用吲哚美辛和不同浓度铁观音提取物处理,检测NO和IL-6的分泌情况,qPCR检测一氧化氮合酶(iNOS)、环氧合酶2(COX-2)、肿瘤坏死因子α(TNF-α)、单核细胞趋化蛋白1(MCP-1)、白细胞介素6(IL-6)mRNA相对表达,Western Blot检测炎症相关蛋白激酶(IKKβ),核转录因子κB抑制因子(IκB)、核转录因子κB p65(NF κB p65)及其磷酸化产物的相对表达。结果显示,铁观音茶提取物能显著抑制炎症介质NO分泌和IL-6蛋白表达量(p<0.05),抑制炎症相关基因iNOS、COX-2、TNF-α和MCP-1等表达,并极显著抑制NF-κB信号通路相关蛋白IKKβ、IkB和p65的磷酸化(p<0.01)。以上结果表明,铁观音茶提取物可明显抑制LPS诱导的RAW264.7细胞炎症反应,其机制可能与抑制NF-κB信号通路激活有关。     

Anti‐inflammatory properties of high pressure‐assisted extracts of Grifola frondosa in lipopolysaccharide‐activated RAW 264.7 macrophages

The aim of this study was to determine the in vitro anti‐inflammatory properties of the shake extract (SE) and the high pressure‐assisted extract (PE) of the mycelia of Grifola frondosa in a lipopolysaccharide‐stimulated RAW 264.7 macrophage model. The content of total polysaccharides and β‐glucans of PE at 600 MPa (PE‐600) was 41.2 and 6.2 mg g^?1 dry weight, respectively, which were significantly higher than SE extracts. The results showed that treatment with 500 μg mL^?1 of PE by 600 MPa (PE‐600) did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS‐induced NO, PGE₂ and intracellular ROS. The PE‐600 inhibited the activation of NF‐kB and then reduced the production of LPS‐induced TNF‐α, IL‐6 and IL‐1β in a dose‐dependent manner. Thus, the PE could be used as an alternative extraction method for improving the extraction efficacy of G. frondosa and serve as an alternative source of anti‐inflammatory agents.     

Anti‐inflammatory activity of rosemary extracts obtained by supercritical carbon dioxide enriched in carnosic acid and carnosol

The in vitro anti‐inflammatory activity of supercritical rosemary (Rosmarinus officinalis L.) extracts (rosemary A and B) is been reported in this study. To achieve that, THP‐1 macrophages were activated using lipopolysaccharide or human ox‐LDL and secretion and gene expression of TNF‐α, IL‐1β, IL‐6 and IL‐10 were evaluated, as well as COX‐2 gene expression. Results indicated that both rosemary extracts (A & B) exhibit high anti‐inflammatory activity although at a higher extent in case of rosemary B extract (5 μg mL^?1), representing a higher quantity of carnosic acid and carnosol than rosemary A. When comparing the activity of the extract to the standard itself, the anti‐inflammatory activity of standards of carnosic acid and carnosol was not as intense as that obtained with rosemary B. These data indicated that although carnosic acid content in the extracts is considered as the main anti‐inflammatory compound, a synergistic interaction with other compounds may play a significant role in enhancing its activity. Results provided the grounds for possible increase in the application of supercritical rosemary extracts in food formulations for mitigation or prevention of inflammatory diseases.     

Anti‐obesity effect of Liupao tea extract by modulating lipid metabolism and oxidative stress in high‐fat‐diet‐induced obese mice

Liupao tea (LPT) is traditional dark Chinese tea. The effect of LPT extract on high‐fat‐diet‐induced obese mice was investigated systematically. The results showed that LPT extract could reduce body weight and significantly alleviate liver damage and fat accumulation. LPT could also decrease the levels of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triglycerides (TG), and low‐density lipoprotein cholesterol (LDL‐C) and increase the level of high‐density lipoprotein cholesterol (HDL‐C) in the liver. It also decreased the serum levels of inflammatory cytokines, including tumor necrosis factor alpha (TNF‐α), interferon gamma (IFN‐γ), interleukin (IL)‐1β, and IL‐6 and increased the serum levels of anti‐inflammatory cytokines, including IL‐10 and IL‐4. Moreover, LPT improved the levels of total superoxide dismutase (T‐SOD), glutathione peroxidase (GSH‐Px), and catalase (CAT) and reduced the level of malondialdehyde (MDA) in the liver. Moreover, LPT could upregulate the mRNA and protein expressions of peroxisome proliferator‐activated receptor alpha (PPAR‐α), lipoprotein lipase (LPL), carnitine palmitoyltransferase 1(CPT1), and cholesterol 7 alpha‐hydroxylase (CYP7A1) and downregulate those of PPAR‐γ and CCAAT/enhancer‐binding protein alpha (C/EBP‐α) in the liver. It also increased the mRNA expression of copper/zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), CAT, gamma‐glutamylcysteine synthetase 1 (GSH1), and GSH‐Px. The components of LPT extract include catechin, rutin, taxifolin, and astragalin, which possibly have a wide range of biological activities. In conclusion, our work verified that LPT extract possessed an anti‐obesity effect and alleviated obesity‐related symptoms, including lipid metabolism disorder, chronic low‐grade inflammation, and liver damage, by modulating lipid metabolism and oxidative stress.     

Enhanced Anti‐Inflammatory Activities by the Combination of Luteolin and Tangeretin

Dietary components in combination may act synergistically and produce enhanced biological activities. Herein, we investigated the anti‐inflammatory effects of 2 flavonoids, that is luteolin (LUT) and tangeretin (TAN) in combination. Lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophages were treated with noncytotoxic concentrations of LUT, TAN, and their combinations. The results showed that LUT/TAN in combination produced synergistic inhibitory effects on LPS‐stimulated production of nitric oxide (NO). ELISA results demonstrated that LUT/TAN in combination caused stronger suppression on the LPS‐induced overexpression of proinflammatory mediators, such as prostaglandin E₂ (PGE₂), interleukin (IL)‐1β, and IL‐6 than LUT or TAN alone. Immunoblotting and Real‐Time PCR analyses showed that LUT/TAN combination significantly decreased LPS‐induced protein and mRNA expression of inducible nitric oxide synthase and cyclooxygenase‐2. These inhibitory effects of the combination treatment were stronger than those produced by LUT or TAN alone. Overall, our results demonstrated for the first time that combination of LUT and TAN produced synergistic anti‐inflammatory effects in LPS‐stimulated RAW 264.7 macrophages.     

Cover Picture: Mol. Nutr. Food Res. 11'2010

Regular issues provide a wide range of research and review articles covering all aspects of Molecular Nutrition & Food Research. Selected topics of issue 11 are: Flavan‐3‐ol C‐glycosides – preparation and model experiments mimicking their human intestinal transit Resveratrol confers resistance against taxol via induction of cell cycle arrest in human cancer cell lines Kaempferol induced apoptosis via endoplasmic reticulum stress and mitochondria‐dependent pathway in human osteosarcoma U‐2 OS cells Diosgenin present in fenugreek improves glucose metabolism by promoting adipocyte differentiation and inhibiting inflammation in adipose tissues Plasma phospholipids n‐3 polyunsaturated fatty acid is associated with metabolic syndrome     

Cover Picture: Mol. Nutr. Food Res. 6'2010

Regular issues provide a wide range of research and review articles covering all aspects of Molecular Nutrition & Food Research. Selected topics of issue 06 are: Measurement of caffeic and ferulic acid equivalents in plasma after coffee consumption: small intestine and colon are key sites for coffee metabolism Comparative resistance of food proteins to adult and infant in vitro digestion models Garlic components inhibit angiotensin II – induced cell cycle progression and migration: involvement of cell cycle inhibitor p27Kip1 and MAPK Diosgenin attenuates inflammatory changes in the interaction between adipocytes and macrophages Oleuropein and hydroxytyrosol inhibit MCF‐7 breast cancer cell proliferation interfering with ERK1/2 activation     

Extracellular Vesicles from Hypoxic Adipocytes and Obese Subjects Reduce Insulin‐Stimulated Glucose Uptake

1 Scope

We investigate the effects of extracellular vesicles (EVs) obtained from in vitro adipocyte cell models and from obese subjects on glucose transport and insulin responsiveness.

2 Methods and results

EVs are isolated from the culture supernatant of adipocytes cultured under normoxia, hypoxia (1% oxygen), or exposed to macrophage conditioned media (15% v/v). EVs are isolated from the plasma of lean individuals and subjects with obesity. Cultured adipocytes are incubated with EVs and activation of insulin signalling cascades and insulin‐stimulated glucose transport are measured. EVs released from hypoxic adipocytes impair insulin‐stimulated 2‐deoxyglucose uptake and reduce insulin mediated phosphorylation of AKT. Insulin‐mediated phosphorylation of extracellular regulated kinases (ERK1/2) is not affected. EVs from individuals with obesity decrease insulin stimulated 2‐deoxyglucose uptake in adipocytes (p = 0.0159).

3 Conclusion

EVs released by stressed adipocytes impair insulin action in neighboring adipocytes.