Bromophenol (5‐bromo‐3,4‐dihydroxybenzaldehyde) isolated from red alga Polysiphonia morrowii inhibits adipogenesis by regulating expression of adipogenic transcription factors and AMP‐activated protein kinase activation in 3T3‐L1 adipocytes

The aim of the present study was to investigate the effect of 5‐bromo‐3,4‐dihydroxybenzaldehyde (BD) isolated from Polysiphonia morrowii on adipogenesis and differentiation of 3T3‐L1 preadipocytes into mature adipocytes and its possible mechanism of action. Levels of lipid accumulation and triglyceride were significantly lower in BD treated cells than those in untreated cells. In addition, BD treatment reduced protein expression levels of peroxisome proliferator‐activated receptor‐γ, CCAAT/enhancer‐binding proteins α, and sterol regulatory element‐binding protein 1 compared with control (no treatment). It also reduced expression levels of adiponectin, leptin, fatty acid synthase, and fatty acid binding protein 4. AMP‐activated protein kinase activation was found to be one specific mechanism involved in the effect of BD. These results demonstrate that BD possesses inhibitory effect on adipogenesis through activating AMP‐activated protein kinase signal pathway.     

Antiobesity effect of baicalin involves the modulations of proadipogenic and antiadipogenic regulators of the adipogenesis pathway

In this study, the antiobesity effects of baicalin, 5,6‐dihydroxyflavone‐7‐glucuronic acid, were characterized using an in vitro system of adipogenesis, i.e. fat cell formation. Baicalin‐treatment of 3T3‐L1 preadipocytes was shown to inhibit triglyceride accumulation and lipid droplet formation during induced adipogenesis. Microarray analyses showed that baicalin modulated the expression of genes located in pathways such as adipogenesis, cholesterol biosynthesis, focal adhesion and others. In the adipogenesis pathway, treatment with baicalin significantly down‐regulated terminal differentiation markers of adipocytes including fatty acid binding protein 4. The effects of baicalin on the core part of the adipogenesis pathway, however, were paradoxical; the expression levels of CCAAT/enhancer binding protein (C/EBP)β and C/EBPδ were up‐regulated, while the expression levels of the peroxisome proliferator‐activated receptor (PPAR)γ and C/EBPα were down‐regulated. The antiadipogenic mechanisms of baicalin can be explained by its effects on the upstream part of adipogenesis pathway; baicalin not only up‐regulates the antiadipogenic regulators, C/EBPγ, C/EBP homologous protein and Kruppel‐like factor (KLF)2, but also down‐regulates the proadipogenic regulator, KLF15. The overall effects of baicalin on these upstream regulators of adipogenesis were antiadipogenic, resulting in the down‐regulation of downstream genes and the inhibition of cellular fat accumulation. Copyright © 2009 John Wiley & Sons, Ltd.     

Brassinin,a phytoalexin in cruciferous vegetables,suppresses obesity‐induced inflammatory responses through the Nrf2‐HO‐1 signaling pathway in an adipocyte‐macrophage co‐culture system

The aim of this study was to investigate the effect of brassinin (BR), a phytoalexin found in plants belonging to the Brassicaceae family, on the obesity‐induced inflammatory response and its molecular mechanism in co‐culture of 3T3‐L1 adipocytes and RAW264.7 macrophages. BR effectively suppressed lipid accumulation by down‐regulating the expression of adipogenic factors, which in turn, were regulated by early adipogenic factors such as CCAAT‐enhancer‐binding protein‐β and Kruppel‐like factor 2. Production of inflammatory cytokines and reactive oxygen species, induced by adipocyte‐conditioned medium, was significantly decreased in BR‐treated cells. This effect of BR was more prominent in contact co‐culture of adipocytes and macrophages with a 90% and 34% reduction in IL‐6 and MCP‐1 levels, respectively. BR also restored adiponectin expression, which was significantly reduced by culturing adipocytes in macrophage‐conditioned medium. In the transwell system, BR increased the protein levels of nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) and its target molecule, hemoxygenase‐1 (HO‐1), by 55%–93% and 45%–48%, respectively, and also increased Nrf2 translocation into the nucleus. However, knockdown of Nrf2 or HO‐1 in RAW264.7 cells restored this BR‐mediated inhibition of IL‐6 and MCP‐1 production. These results indicated that BR inhibited obesity‐induced inflammation via the Nrf2‐HO‐1 pathway.     

Down‐regulatory effect of usnic acid on nuclear factor‐κB‐dependent tumor necrosis factor‐α and inducible nitric oxide synthase expression in lipopolysaccharide‐stimulated macrophages RAW 264.7

The purpose of this study was to investigate the molecular mechanisms that are responsible for the antiinflammatory effect of usnic acid (UA). UA is one of the most common and abundant lichen metabolites. The present study examined the effects of UA on the tumor necrosis factor‐α (TNF‐α) and nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages and the underlying molecular mechanisms. UA decreased the TNF‐α level in LPS‐stimulated RAW264.7 macrophages in dose‐dependent manner, the IC₅₀ value was 12.8 µM. RT‐PCR analysis indicated that it inhibited TNF‐α mRNA expression. Furthermore, it inhibited NO production in LPS‐activated RAW264.7 macrophages, the IC₅₀ value was 4.7 µM. Western blot analysis showed that UA attenuated LPS‐induced synthesis of iNOS protein and nuclear translocation of NF‐κB p65 in the macrophages, in parallel. UA also inhibited LPS‐mediated I‐κBα degradation. Taken together, this suggests that UA has an antiinflammatory effect by inhibiting TNF‐α and iNOS expression, possibly through suppression of nuclear translocation of NF‐κB p65 and I‐κBα degradation. Copyright © 2008 John Wiley & Sons, Ltd.     

Antiinflammatory effects of Epimedium brevicornum water extract on lipopolysaccharide‐activated RAW264.7 macrophages

Epimedium brevicornum Maxim (Berberidaceae) possesses estrogenic properties. It is one of the most widespread herbal remedies used in Oriental medicine. The present study investigated the effects of Epimedium brevicornum water extract (EB) on proinflammatory mediators secreted from lipopolysaccharide (LPS)‐induced RAW264.7 macrophages. EB significantly inhibited the production of nitric oxide (NO), interleukin (IL)‐3, IL‐10, IL‐12p40, interferon‐inducible protein‐10, keratinocyte‐derived chemokine, vascular endothelial growth factor, monocyte chemotactic protein‐1 and granulocyte macrophage‐colony stimulating factor in LPS‐induced RAW264.7 cells at concentrations of 25, 50, 100 and 200 μg/mL (p < 0.05). These results suggest that EB has antiinflammatory activity related to its inhibition of NO, cytokine, chemokine and growth factor production in macrophages. Copyright © 2010 John Wiley & Sons, Ltd.     

银杏叶提取物对H2O2诱导的巨噬细胞凋亡的抑制作用

 目的研究银杏叶提取物(EGb761)对H₂O₂所致RAW264.7巨噬细胞凋亡的保护作用。方法以H₂O₂诱导RAW264.7巨噬细胞凋亡为实验模型,用噻唑蓝(MTT)实验、流式细胞术、蛋白质印迹分析、琼脂糖凝胶电泳和荧光分析分别检测细胞存活率、线粒体膜电位、细胞色素C的释放和Bax,bcl-2蛋白水平、DNA的降解、半胱氨酰天冬氨酸特异性蛋白酶-3(caspase-3)活性。结果EGb761能明显降低H₂O₂对RAW264.7细胞的氧化损伤,提高细胞的存活率；维持线粒体膜的完整性,抑制跨膜电位的耗散和细胞色素C的释放；抑制caspase-3的活化和DNA的降解。结论EGb761具有清除活性氧,减轻H₂O₂所致RAW264.7细胞的氧化损伤,在对H₂O₂诱导的细胞凋亡中发挥重要的抗凋亡作用。     

Regulation of obesity and lipid disorders by extracts from Angelica acutiloba root in high-fat diet-induced obese rats

The aim of this study was to investigate the antiobesity and antihyperlipidemic effects of Angelica acutiloba root (Japanese Dong Quai). High‐fat diet (HFD)‐induced obese rats were treated orally with the polyphenolic‐rich extract of Angelica acutiloba root (AARE) once daily for 8 weeks. The AARE (300 mg/kg per day) supplementation significantly lowered body weight gain, visceral fat‐pad weights and plasma lipid levels, as well as the coronary artery risk index and the atherogenic index of HFD‐fed rats. The AARE caused dose related reductions in the hepatic triglyceride and cholesterol contents, as well as lowered hepatic lipid droplet accumulation and epididymal adipocyte size in the HFD‐fed rats. The AARE reversed the HFD‐induced down‐regulation of the hepatic peroxisome proliferator activated receptor‐α (PPARα). The HFD‐induced decreases of the hepatic protein level of acyl‐CoA oxidase (ACO), and the cytochrome P450 isoform 4A1 (CYP4A1) was up‐regulated by AARE. The elevated expressions of hepatic sterol regulatory element binding proteins (SREBPs) of HFD‐fed rats were lowered by AARE. These results suggest that AARE attenuated visceral fat accumulation and improved hyperlipidemia in HFD‐induced obesity by increasing lipid metabolism through the down‐regulation of SREBPs and enhanced the expression of ACO and CYP4A1 in the liver, which was likely mediated by up‐regulation of the expression of hepatic PPARα. Copyright © 2011 John Wiley & Sons, Ltd.     

Praeruptorin a inhibits lipopolysaccharide‐induced inflammatory response in murine macrophages through inhibition of NF‐κB pathway activation

Praeruptorin A (PA) is a pyranocoumarin compound isolated from the dried root of Peucedanum praeruptorum Dunn (Umbelliferae). However, the antiinflammatory effect of PA has not been reported. The present study investigated the antiinflammatory effect of PA in lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophage cells. PA significantly inhibited the LPS‐induced production of nitric oxide (NO), interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α). The mRNA and protein expressions of inducible nitric oxide synthase (iNOS), IL‐1β and TNF‐α were also suppressed by this compound. Further study showed that PA decreased the cytoplasmic loss of inhibitor κB‐α (IκB‐α) protein and inhibited the translocation of NF‐κB from cytoplasm to nucleus. Taken together, the results suggest that PA may exert antiinflammatory effects in vitro in LPS‐stimulated RAW 264.7 macrophages through inhibition of NF‐κB signal pathway activation. Copyright © 2010 John Wiley & Sons, Ltd.     

The Essential Oil of Bergamot Stimulates Reactive Oxygen Species Production in Human Polymorphonuclear Leukocytes

Bergamot (Citrus aurantium L. subsp. bergamia) essential oil (BEO) is used in folk medicine as an antiseptic and anthelminthic and to facilitate wound healing. Evidence indicates that BEO has substantial antimicrobial activity; however its effects on immunity have never been examined. We studied the effects of BEO on reactive oxygen species (ROS) production in human polymorphonuclear leukocytes (PMN) and the role of Ca²⁺ in the functional responses evoked by BEO in these cells. Results show that BEO increased intracellular ROS production in human PMN, an effect that required the contribution of extracellular (and, to a lesser extent, of intracellular) Ca²⁺. Bergamot essential oil also significantly increased ROS production induced by the chemotactic peptide N‐formyl‐Met‐Leu‐Phe and reduced the response to the protein kinase C activator phorbol myristate acetate. In conclusion, this is the first report showing the ability of BEO to increase ROS production in human PMN. This effect could both contribute to the activity of BEO in infections and in tissue healing as well as underlie an intrinsic proinflammatory potential. The relevance of these findings for the clinical uses of BEO needs careful consideration. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of Ganoderma lucidum extract on adipocyte differentiation and adiponectin gene expression in the murine pre‐adipocyte cell line, 3T3‐L1

Ganoderma lucidum (G. lucidum), a traditional Chinese medicine, has been used for the treatment of various diseases including cancer and atherosclerosis. In this study, the positive effect of G. lucidum on metabolic syndrome was investigated in more detail by the use of 3T3‐L1 pre‐adipocyte cells. Treatment of 3T3‐L1 cells with G. lucidum extract (GE) significantly promoted adipocyte differentiation and adiponectin production in a dose‐dependent manner, as assessed by Oil‐Red O staining, quantitative RT‐PCR and ELISA. Treatment with GW9662, an inhibitor for peroxisome proliferator‐activated receptor‐gamma (PPARgamma), significantly attenuated GE‐dependent adipocyte differentiation and adiponectin gene expression, suggesting the involvement of PPARgamma. Moreover, a reporter gene assay using GAL4‐PPAR fusion proteins revealed that GE enhances GAL4‐PPARgamma and GAL4‐PPARalpha activities. These results indicate the presence of natural compounds possessing PPARgamma and PPARalpha activating properties in G. lucidum. Copyright © 2010 John Wiley & Sons, Ltd.     

Antiobesity Effects of a Sulfur Compound Thiacremonone Mediated via Down-regulation of Serum Triglyceride and Glucose Levels and Lipid Accumulation in the Liver of db/db Mice

Garlic is widely used as a spice. Garlic extracts exert anticancer and antiinflammatory effects, but its antiobesity efficacy studies have produced conflicting results. The antiobesity effects of thiacremonone, a sulfur compound isolated from garlic, was evaluated in obese db/db mice. Thiacremonone was orally administrated to mice for 3 weeks. The thiacremonone‐treated db/db mice showed a loss of body weight and decrease in blood triglyceride and glucose levels compared with the control mice. Histological analysis further revealed that thiacremonone significantly decreased lipid accumulation in the fatty livers of treated db/db mice. It was observed that GLUT‐4 expression and glucose uptake were up‐regulated by thiacremonone in 3T3‐L1 adipocytes. Thiacremonone treatment also suppressed expression levels of acetyl‐CoA carboxylase (ACC) and fatty acid synthase (FAS), which are involved in lipid metabolism, in the liver of db/db mice. In addition, thiacremonone enhanced peroxisome proliferator‐activated receptor γ (PPARγ) expression in the fatty liver. Taken together, these results suggest that thiacremonone may play a vital role in improving the management of obesity and related metabolic syndromes via inhibition of lipid accumulation. Copyright © 2012 John Wiley & Sons, Ltd.