5‐Hydroxyferulic acid methyl ester isolated from wasabi leaves inhibits 3T3‐L1 adipocyte differentiation

To investigate the compounds present in wasabi leaves (Wasabia japonica Matsumura) that inhibit the adipocyte differentiation, activity‐guided fractionation was performed on these leaves. 5‐Hydroxyferulic acid methyl ester ( 1 : 5‐HFA ester), one of the phenylpropanoids, was isolated from wasabi leaves as a compound that inhibits the adipocyte differentiation. Compound 1 suppressed the intracellular lipid accumulation of 3T3‐L1 cells without significant cytotoxicity. Gene expression analysis revealed that 1 suppressed the mRNA expression of 2 master regulators of adipocyte differentiation, PPARγ and C/EBPα. Furthermore, 1 downregulated the expression of adipogenesis‐related genes, GLUT4, LPL, SREBP‐1c, ACC, and FAS. Protein expression analysis revealed that 1 suppressed PPARγ protein expression. Moreover, to investigate the relationship between the structure and activity of inhibiting the adipocyte differentiation, we synthesized 12 kinds of phenylpropanoid analog. Comparison of the activity among 1 and its analogs suggested that the compound containing the substructure that possess a common functional group at the ortho position such as a catechol group exhibits the activity of inhibiting the adipocyte differentiation. Taken together, our findings suggest that 1 from wasabi leaves inhibits adipocyte differentiation via the downregulation of PPARγ.     

Effects of Sinensetin on Lipid Metabolism in Mature 3T3‐L1 Adipocytes

Sinensetin is a rare polymethoxylated flavone found in certain citrus fruits. In this study, we investigated the effects of sinensetin on lipid metabolism in mature 3T3‐L1 adipocytes. Sinensetin decreased the expression of sterol regulatory element‐binding protein 1c (SREBP1c), suggesting its antiadipogeneic property via downreguation of SREBP1c. Also, sinensetin increased the phosphorylation of protein kinase A and hormone‐sensitive lipase, indicating its lipolytic property via a cAMP‐mediated signaling pathway. Moreover, sinensetin inhibited insulin‐stimulated glucose uptake by decreasing the phosphorylation of insulin receptor substrate and Akt. Furthermore, sinensetin increased the phosphorylation of AMP‐activated protein kinase (AMPK) and acetyl‐CoA carboxylase. It also upregulated mRNA expression of carnitine palmitoyltransferase‐1a, suggesting that sinensetin enhances fatty acid β‐oxidation through the AMPK pathway. Taken together, these results suggest that sinensetin may have potential as a natural agent for prevention/improvement of obesity. Copyright © 2012 John Wiley & Sons, Ltd.     

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.     

Zerumbone Suppresses IL‐1β‐induced Cell Migration and Invasion by Inhibiting IL‐8 and MMP‐3 Expression in Human Triple‐negative Breast Cancer Cells

Inflammation is a key regulatory process in cancer development. Prolonged exposure of breast tumor cells to inflammatory cytokines leads to epithelial‐mesenchymal transition, which is the principal mechanism involved in metastasis and tumor invasion. Interleukin (IL)‐1β is a major inflammatory cytokine in a variety of tumors. To date, the regulatory mechanism of IL‐1β‐induced cell migration and invasion has not been fully elucidated. Here, we investigated the effect of zerumbone (ZER) on IL‐1β‐induced cell migration and invasion in breast cancer cells. The levels of IL‐8 and matrix metalloproteinase (MMP)‐3 mRNA were analyzed by real‐time polymerase chain reaction. The levels of secreted IL‐8 and MMP‐3 protein were analyzed by enzyme‐linked immunosorbent assay and western blot analysis, respectively. Cell invasion and migration was detected by Boyden chamber assay. The levels of IL‐8 and MMP‐3 expression were significantly increased by IL‐1β treatment in Hs578T and MDA‐MB231 cells. On the other hand, IL‐1β‐induced IL‐8 and MMP‐3 expression was decreased by ZER. Finally, IL‐1β‐induced cell migration and invasion were decreased by ZER in Hs578T and MDA‐MB231 cells. ZER suppresses IL‐1β‐induced cell migration and invasion by inhibiting IL‐8 expression and MMP‐3 expression in TNBC cells. ZER could be a promising therapeutic drug for treatment of triple‐negative breast cancer patients. Copyright © 2014 John Wiley & Sons, Ltd.     

Anti‐diabetic Activity of Swertiamarin is due to an Active Metabolite,Gentianine, that Upregulates PPAR‐γ Gene Expression in 3T3‐L1 cells

We have previously shown the anti‐diabetic effects of swertiamarin; however, pharmacokinetic analysis showed that swertiamarin had a plasma half‐life of 1.3 h. Gentianine is an active metabolite of swertiamarin that possesses a pharmacophoric moiety. The aim of this study was to explore the possibility whether the anti‐diabetic effect of swertiamarin is due to gentianine. Swertiamarin treatment had no significant effect on adipogenesis, or the mRNA expression of PPAR‐γ and GLUT‐4; however, there was a significant increase in the mRNA expression of adiponectin. On the other hand, treatment with gentianine significantly increased adipogenesis, which was associated with a significant increase in the mRNA expression of PPAR‐γ, GLUT‐4 and adiponectin. These findings suggest, for the first time, that the anti‐diabetic effect of swertiamarin is due to gentianine, an active metabolite of swertiamarin. Copyright © 2012 John Wiley & Sons, Ltd.     

Genistein suppresses adipogenesis of 3T3‐L1 cells via multiple signal pathways

Genistein, an isoflavone, was shown to have therapeutic effects for obesity, diabetes and cardiovascular diseases. This study investigated the effect and underlying mechanism of genistein on adipogenesis in 3T3‐L1 preadipocytes. Genistein inhibited lipid accumulation and decreased the nonesterified fatty acid (NEFA) content of 3T3‐L1 on day 6 after the induction of differentiation with methylisobutylxanthine, dexamethasone and insulin (MDI). Genistein recovered nitric oxide (NO) release suppressed by MDI and the results were consistent with the expression of endothelial NO synthase (eNOS) assayed by western blotting. Pretreatment with genistein inhibited the phosphorylation of p38 mitogen‐activated protein kinase (p38 MAPK) stimulated with 10 µg/mL of insulin. Furthermore, genistein inhibited the expression of fatty acid synthase (FAS) from 178% of the MDI group to 74%. SB203580, a p38 inhibitor, mimicked the FAS inhibition effect of genistein, suggesting that the inhibitory effect of genistein on FAS was partially via the p38 pathway. On the other hand, genistein abolished the phosphorylation of janus‐activated kinase 2 (JAK2) in response to MDI. AG490, a JAK2 inhibitor, suppressed the expression of CCAAT/enhancer binding protein alpha (C/EBPα), a marker of adipocyte differentiation. The findings suggest that genistein attenuates the differentiation of 3T3‐L1 involving multiple signal pathways. Copyright © 2008 John Wiley & Sons, Ltd.     

Hydroxy‐Safflower Yellow A inhibits the TNFR1‐Mediated Classical NF‐κB Pathway by Inducing Shedding of TNFR1

Hydroxy‐safflower yellow A (HSYA) is the major active component of safflower, a traditional Asia herbal medicine well known for its cardiovascular protective activities. The purpose of this study was to investigate the effect of HSYA on TNF‐α‐induced inflammatory responses in arterial endothelial cells (AECs) and to explore the mechanisms involved. The results showed that HSYA suppressed the up‐regulation of ICAM‐1 expression in TNF‐α‐stimulated AECs in a dose‐dependent manner. High concentration (120 μM) HSYA significantly inhibited the TNF‐α‐induced adhesion of RAW264.7 cells to AECs. HSYA blocked the TNFR1‐mediated phosphorylation and degradation of IκBα and also prevented the nuclear translocation of NF‐κB p65. Moreover, HSYA reduced the cell surface level of TNFR1 and increased the content of sTNFR1 in the culture media. TNF‐α processing inhibitor‐0 (TAPI‐0) prevented the HSYA inhibition of TNFR1‐induced IκBα degradation, implying the occurrence of TNFR1 shedding. Furthermore, HSYA induced phosphorylation of TNF‐α converting enzyme (TACE) at threonine 735, which is thought to be required for its activation. Conclusively, HSYA suppressed TNF‐α‐induced inflammatory responses in AECs, at least in part by inhibiting the TNFR1‐mediated classical NF‐κB pathway. TACE‐mediated TNFR1 shedding can be involved in this effect. Our study provides new evidence for the antiinflammatory and anti‐atherosclerotic effects of HSYA. Copyright © 2016 John Wiley & Sons, Ltd.     

Inhibitory effects of green tea catechin on the lipid accumulation in 3T3‐L1 adipocytes

The aim of the present study was to evaluate the effects of green tea (‐)‐epigallocatechin‐3‐gallate (EGCG) on the depletion of accumulated fat in differentiated 3T3‐L1 adipocytes. Intracellular lipid accumulation was decreased significantly after 24 h of incubation with 10 µm EGCG, while the viability of adipocytes was reported to be unaffected. Under the same experimental conditions, the amount of glycerol released from cells into the medium was increased by 10 µm EGCG. The level of mRNA in the 3T3‐L1 adipocytes was analysed by quantitative real‐time RT‐PCR. EGCG notably increased the mRNA level of hormone sensitive lipase (HSL), which catalyses the rate‐limiting stage in hydrolysis of stored triacylglycerol to monoacylglycerol and free fatty acids. In conclusion, the experiment produced results which showed that green tea EGCG effectively depleted fat accumulation via the stimulation of lipolysis and increased HSL gene expression in 3T3‐L1 adipocytes. These results may relate to the mechanism by which EGCG modulates lipolysis in adipocytes. Copyright © 2008 John Wiley & Sons, Ltd.     

Phloroglucinol Protects INS‐1 Pancreatic β‐cells Against Glucotoxicity‐Induced Apoptosis

Decreasing numbers, and impaired function, of pancreatic β‐cells are key factors in the development of type 2 diabetes. This study was designed to investigate whether phloroglucinol protected pancreatic β‐cells against glucotoxicity‐induced apoptosis using a rat insulinoma cell line (INS‐1). High glucose treatment (30 mM) induced INS‐1 cell death; however, the level of glucose‐induced apoptosis was significantly reduced in cells treated with 100‐μM phloroglucinol. Treatment with 10–100‐μM phloroglucinol increased cell viability and decreased intracellular levels of reactive oxygen species, nitric oxide, and lipid peroxidation dose‐dependently in INS‐1 cells pretreated with high glucose. Furthermore, phloroglucinol treatment markedly reduced the protein expression of Bax, cytochrome c, and caspase 9, while increasing anti‐apoptotic Bcl‐2 protein expression. Cell death type was examined using annexin V/propidium iodide staining, revealing that phloroglucinol markedly reduced high glucose‐induced apoptosis. These results demonstrated that phloroglucinol could be useful as a potential therapeutic agent for the protection of pancreatic β‐cells against glucose‐induced apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.     

Inhibitory Effects of (2′R)‐2′,3′‐dihydro‐2′‐(1‐hydroxy‐1‐methylethyl)‐2,6′‐bibenzofuran‐6,4′‐diol on Mushroom Tyrosinase and Melanogenesis in B16‐F10 Melanoma Cells

(2′R)‐2′,3′‐Dihydro‐2′‐(1‐hydroxy‐1‐methylethyl)‐2,6′‐bibenzofuran‐6,4′‐diol (DHMB) is a natural compound extracted from Morus notabilis. It was found that DHMB acts as a competitive inhibitor against mushroom tyrosinase with a Ki value of 14.77 μM. Docking results further indicated that it could form strong interactions with one copper ion with a distance of 2.7 Å, suggesting the mechanism of inhibition might be due to chelating copper ions in the active site. Furthermore, melanin production in B16‐F10 murine melanoma cells was significantly inhibited by DHMB in a concentration‐dependent manner without cytotoxicity. The results of western blotting also showed that DHMB decreased 3‐isobuty‐1‐methxlzanthine‐induced mature tyrosinase expression. Taken together, these findings indicated that DHMB may be a new promising pigmentation‐altering agent for agriculture, cosmetic, and therapeutic applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of mollugin on apoptosis and adipogenesis of 3T3-L1 preadipocytes

The effect of mollugin, isolated from the roots of Rubia cordifolia L., on cell viability, apoptosis and adipogenesis in 3T3‐L1 preadipocytes was investigated. The inhibitory effect of mollugin (40–60 µm ) on cell viability was more significant in differentiated adipocytes than in 3T3‐L1 preadipocytes. In 3T3‐L1 cells, the cytotoxicity of mollugin was accompanied by apoptotic events including mitochondrial membrane potential (Δψm) loss and activation of caspase‐9, ‐3 and ‐7, leading to PARP degradation. Although the presence of 20 µm mollugin during induced adipocytic differentiation of 3T3‐L1 cells for 6 days failed to affect the cell viability, it could almost completely abrogate the differentiation‐associated morphology change and intracellular lipid accumulation. A similar level of inhibition was observed, when 20 µm mollugin was present during the early stage (D0–D2) of the differentiation period. In addition, the expression of C/EBPα, PPARγ1 and PPARγ2 was significantly down‐regulated. The presence of 20 µm mollugin during either middle stage (D2–D4) or late stage (D4–D6) of the differentiation period, however, caused the inhibition to a lesser extent. These results indicated that mollugin at high concentrations (40–60 µm ) exerted cytotoxicity via inducing apoptosis, whereas mollugin at a low concentration (20 µm ) suppressed adipocytic differentiation without exerting cytotoxicity in 3T3‐L1 preadipocytes. Copyright © 2010 John Wiley & Sons, Ltd.     

5,7‐Dihydroxy‐6‐Methoxy‐Flavonoids Eliminate HIV‐1 D3‐transfected Cytoprotective Macrophages by Inhibiting the PI3K/Akt Signaling Pathway

Flavonoids, well‐documented secondary metabolites in many vegetables and plants, exhibit antiinflammatory, anti‐oxidant, anti‐microbial, and anticancer activities. However, their cytotoxic effects against human immunodeficiency virus type 1 (HIV‐1)‐infected cytoprotective macrophages have not been studied. In the present study, we investigated their effects and their molecular mechanisms. Treatment with flavonoids in the presence of lipopolysaccharide (LPS)/cycloheximide (CHX) potently eliminated HIV‐1 Tat‐transduced cytoprotective human microglial CHME5 cells; the 5,7‐dihydroxy‐6‐methoxy‐flavonoids oroxylin A and tectorigenin, at a concentration of 10 μM, most potently eliminated the cytoprotective phenotype. These flavonoids eliminated Tat‐transduced CHME5 cells, D3‐transfected CHME5 cells, and HIV‐1 D3‐infected human primary macrophages, in a dose‐dependent manner. Furthermore, oroxylin A and tectorigenin potently inhibited LPS/CHX‐induced phosphorylation of phosphoinositide 3‐kinase (PI3K), pyruvate dehydrogenase lipoamide kinase isozyme 1, Akt, and glycogen synthase kinase‐3β in the Tat‐transduced cells, D3‐transfected CHME5 cells, and D3‐infected human primary macrophages. Based on these findings, 5,7‐dihydroxy‐6‐methoxy‐flavonoids may eliminate HIV‐1 infected cytoprotective macrophages by inhibiting the PI3K/Akt signaling pathway and deliver anti‐HIV‐1 effects in vivo by shortening the lifespan of infected macrophages. Copyright © 2015 John Wiley & Sons, Ltd.     

Sour Cherry Seed Kernel Extract Increases Heme Oxygenase‐1 Expression and Decreases Representation of CD3+ TNF‐α + and CD3 + IL‐8+ Subpopulations in Peripheral Blood Leukocyte Cultures from Type 2 Diabetes Patients

The present study evaluates a hypothesis that sour cherry (Prunus cerasus) seed extracts (SCE) modulate CD3+ T lymphocyte activity in ways predictive of potential for uses of SCE in management of inflammatory diseases. Peripheral blood mononuclear cells (PBMC) from 12 type 2 diabetes (T2DM) patients and eight healthy control subjects were cultured 24 h with 100 ng/ml lipopolysaccharide (LPS) to increase inflammatory signaling and co‐incubated with 0.5–100 µg/ml SCE. Cultures were evaluated by two‐color flow cytometry for percent representation of CD3+ IL8+ and CD3 + TNF‐α + cells which express interleukin‐8 (IL‐8), and tumor necrosis factor‐α, (TNF‐α+) respectively, and by enzyme‐linked immunoassay for lymphocyte‐associated heme oxygenase‐1 (HO‐1, known to be induced by SCE). SCE dosage ranges of 0.5–100 µg/ml in cell cultures significantly suppressed LPS‐increased CD3 + TNF‐α + and CD3 + IL8+ representation from all participants (p < 0.05), with greater pharmacological effect noted in suppression of CD3 + TNF‐α + noted in cells from T2DM patients versus healthy control subjects. These effects correlated with increased HO‐1 expression in SCE‐treated PBMC from all subjects (p < 0.05). Since TNF‐α and IL‐8 are diagnostic/prognostic biomarkers for many inflammatory syndromes, the capacity of SCE to down‐regulate representation of cells that express them suggests potential for therapeutic use of SCE in T2DM and other diseases. Copyright © 2012 John Wiley & Sons, Ltd.     

Calycosin ameliorates doxorubicin‐induced cardiotoxicity by suppressing oxidative stress and inflammation via the sirtuin 1–NOD‐like receptor protein 3 pathway

The limitation of doxorubicin (DOX), which is widely used for the treatment of solid tumors and hematologic malignancies, is a vital problem in clinical application. The most serious of limit factors is cardiotoxicity. Calycosin (CA), an isoflavonoid that is the major active component in Radix astragali, has been reported in many bioactivities including antitumor, anti‐inflammatory, and cardioprotection. The aim of the study was to investigate the effects and mechanisms of CA on DOX‐induced cardiotoxicity in vitro and in vivo. CA increased H9c2 cell viability and reduced apoptosis induced by DOX via Bcl‐2, Bax, and the PI3K‐Akt signaling pathway. Moreover, CA prevented DOX‐induced oxidative stress in cells by decreasing the generation of reactive oxygen species. Similarly, oxidative stress was inhibited by CA through the increased activities of antioxidant enzymes such as glutathione peroxidase, catalase, and superoxide dismutase and decreased the levels of aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde in vivo. Furthermore, the levels of sirtuin 1 (Sirt1)–NOD‐like receptor protein 3 (NLRP3) and related proteins were ameliorated by CA in cells and in mice hearts. When H9c2 cells were treated by Ex527 (Sirt1 inhibitor), the effect of CA on expressions of NLRP3 and thioredoxin‐interacting protein was suppressed. In conclusion, the results suggested that CA might be a cotreatment with DOX to ameliorate cardiotoxicity by Sirt1–NLRP3 pathway.