Epimedium koreanum Nakai and its main constituent icariin suppress lipid accumulation during adipocyte differentiation of 3T3-L1 preadipocytes.

Obesity is associated with a number of metabolic abnormalities such as type 2 diabetes and has become a major health problem worldwide. In the present study, we investigated the effects of Epimedium koreanum Nakai (Herba Epimedii, HE) and its main constituent icariin on the adipocyte differentiation in 3T3-L1 preadipocytes. HE extract and icariin significantly reduced lipid accumulation and suppressed the expressions of PPARγ, C/EBPα, and SREBP-1c in 3T3-L1 adipocytes. They also inhibited fatty acid synthase (FAS), acyl-Co A synthase (ACS1), and perilipin. Moreover, HE extract and icariin markedly increased the phosphorylation of AMPK. These results indicated that HE extract and icariin can inhibit the adipocyte differentiation through downregulation of the adipogenic transcription factors, suggesting that HE containing icariin may be used as a potential therapeutic agent in the treatment and prevention of obesity.

Effects of Icariin on insulin resistance via the activation of AMPK pathway in C2C12 mouse muscle cells.

Insulin resistance in skeletal muscle is a major risk factor for the development of type 2 diabetes (T2D). In this study, we investigated the effect of icariin on insulin resistance in C2C12 mouse skeletal muscle cells. C2C12 myoblasts were differentiated into myotubes for five days, then treated with icariin (50 and 100µM) or metformin (1mM) in the presence of 100nM insulin for 24h. Adiponectin production was measured in culture media by ELISA, and AMP-activated protein kinase (AMPK)/insulin signaling pathway activation was assessed by the western blot analysis. Icariin significantly increased adiponectin production in C2C12 myotubes. Moreover, icariin markedly promoted the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). Icariin up-regulated the expression of phosphatidylinositol 3-kinase (PI3K) and the phosphorylation of insulin receptor substrate-1 (IRS-1) in C2C12 myotubes. These results suggest that icariin has therapeutic potential for the treatment of T2D via the regulation of insulin resistance in skeletal muscle.

Selective therapeutic effect of cornus officinalis fruits on the damage of different organs in STZ-induced diabetic rats.

The aim of the present study was to identify the selective therapeutic effects of Corni Fructus (Cornus officinalis Sieb. et Zucc.) on different organs in streptozotocin (STZ)-induced diabetic rats. Diabetes in rats was induced by intraperitonal injection with STZ at a dose of 30 mg/kg body weight (bw) for 3 days (once per a day). STZ-induced diabetic rats were orally administrated Corni Fructus (CF) extract at 300 mg/kg or metformin at 250 mg/kg daily for 4 weeks. Blood glucose and triglyceride (TG) in sera and urine total volume were measured. Histopathological changes of different organs, pancreas, liver, kidney, and lung tissues were observed by H&E staining. The expression of insulin and α-smooth muscle actin (α-SMA) was investigated in pancreas, and kidney by immunohistochemistry, respectively. The results revealed that CF extract significantly decreased the serum levels of blood glucose, and TG, and also urine total volume in STZ-induced diabetic rats. The histological examinations revealed amelioration of diabetes-induced pancreas injury including pathological changes of the Langerhans's islet and glomerular with their loss after the administration of CF extraction. Moreover, the administration of CF extract increased the numbers of insulin releasing beta cells in pancreas and also inhibited the expression of α-SMA in kidney of STZ-induced diabetic rats. On the other hand, CF extract showed no effect on the pathological damages of liver and lung in STZ-induced diabetic rats. These results demonstrated that CF extract may have a selective therapeutic potential through the control of hyperglycemia, and the protection of pancreas and kidney against diabetic damage.

Osteogenesis induction of periodontal ligament cells onto bone morphogenic protein-2 immobilized PCL fibers.

The purpose of this study was to develop bone morphogenic protein-2 (BMP-2) immobilized PCL fibers to induce osteogenic differentiation of periodontal ligament cells (PDLCs). The PCL fiber surface was modified with heparin-dopamine (Hep-DOPA) (Hep-PCL) and further immobilized with BMP-2 (BMP-2/Hep-PCL). PCL fibers and surface-modified PCL fibers (Hep-PCL and BMP-2/Hep-PCL) were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle. Osteogenic differentiation of PDLCs was demonstrated by alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The results of XPS and contact angle revealed that Hep-DOPA and BMP-2 were successfully immobilized onto the PCL surface and that the BMP-2/Hep-PCL fibers have more hydrophilic surface properties than PCL fibers alone. ALP activity, calcium deposition, and gene expression on BMP-2/Hep-PCL fibers showed significantly induced osteogenic differentiation relative to PCL fibers. Therefore, we suggest that BMP-2/Hep-PCL fibers have the potential to effectively induce osteogenic differentiation of PDLCs.

Anti-inflammatory effects of prosapogenin III from the dried roots of Liriope platyphylla in LPS-stimulated RAW264.7 cells.

Liriope platyphylla has been reported to possess various biological activities, including anti-asthma, anti-inflammation, anti-diabetes, and neuriotogenic properties. In this study, we evaluated the effects of prosapogenin III isolated from the roots of L. platyphylla (Liriopis Tuber) on inflammatory responses in lipopolysaccharide (LPS) stimulated RAW264.7 mouse macrophages. We investigated LPS-induced production/expression of inflammatory mediators such as nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxigenase-2 (COX-2), and proinflammatory cytokines, including interleukin-1ß (IL-1ß) and interleukin (IL)-6 in RAW264.7 cells. We also performed Western blot analysis for determination of the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK) 1/2, p38, and c-Jun N-terminal kinase (JNK), and nuclear translocation of nuclear factor-κB (NF-κB) in LPS-stimulated cells. Treatment with prosapogenin III resulted in significant inhibition of NO production in LPS-stimulated Raw264.7 cells through suppression of iNOS expression. Treatment with prosapogenin III resulted in a significant decrease in expressions of COX-2, IL-1ß, and IL-6 through down-regulation of their mRNA or protein in LPS-stimulated cells. In addition, treatment with prosapogenin III resulted in potently inhibited phosphorylation of three MAPKs, including ERK1/2, p38, and JNK in LPS-stimulated cells. Treatment with prosapogenin III also resulted in suppression of the nuclear translocation of NF-κB in LPS-stimulated cells. These results indicate that prosapogenin III of Liriopis Tuber has anti-inflammatory effects in activated macrophages through inhibition of production of inflammatory mediators by blockade of the MAPK/NF-κB pathway.

The extract of Cinnamomum cassia twigs inhibits adipocyte differentiation via activation of the insulin signaling pathway in 3T3-L1 preadipocytes.

CONTEXT: Obesity is associated with a number of diseases with metabolic abnormalities such as type 2 diabetes (T2D). Medicinal plants have been widely used for the treatment of obesity and related complications. OBJECTIVE: In this study, we investigated the antidiabetic properties of the extract of twigs of Cinnamomum cassia Blume (Lauraceae) (Cinnamomi Ramulus; CR) in 3T3-L1 murine preadipocytes. MATERIALS AND METHODS: 3T3-L1 cells were differentiated into adipocytes for 3 d in insulin-conditioned medium and then treated with CR extract at concentrations of 100 and 500 µg/mL for 6 d. Adipocyte differentiation was measured by Oil Red O staining, and the expression of master transcription factors, peroxisome proliferator-activated receptor-gamma (PPARγ), CCAAT/enhancer binding protein-alpha (C/EBPα), and sterol regulatory element binding protein-1c (SREBP-1c), and lipid metabolism factors were investigated by reverse transcription-polymerase chain reaction (RT-PCR). The activation of the AMP-activated protein kinase (AMPK)/insulin signaling pathway was assessed by western blot analysis. RESULTS: CR extract significantly reduced lipid accumulation and down-regulated the expression of PPARγ, C/EBPα, and SREBP-1c in 3T3-L1 adipocytes. CR extract also suppressed the expression of fatty acid synthase (FAS), acyl-CoA synthase, and perilipin. Moreover, CR extract markedly up-regulated the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). In addition, CR extract effectively increased the expression levels of glucose transporter-4 (GLUT-4), phosphatidylinositol 3-kinase (PI3K), and insulin receptor substrate-1 (IRS-1) in 3T3-L1 adipocytes. DISCUSSION AND CONCLUSION: These results suggest that CR extract may have therapeutic potential as a natural agent for the improvement of T2D via regulation of the insulin-dependent signaling pathway.

Wen-pi-tang-Hab-Wu-ling-san, a Polyherbal Medicine, Attenuates ER Stress in 3T3-L1 Preadipocytes by Promoting the Insulin Signaling Pathway.

The endoplasmic reticulum (ER) is an organelle that functions to synthesize, fold, and transport proteins. ER stress is a key link between type 2 diabetes (T2D), obesity, and insulin resistance. In this study, we investigated the effect of WHW on the ER stress response and the insulin signaling pathway in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were differentiated into adipocytes, and ER stress was then induced by treatment with tunicamycin. ER stress-induced adipocytes were treated with different concentrations of WHW for 24 h. The expression of ER stress-related molecules such as X-box-binding protein-1 (XBP-1), glucose-regulated protein 78 (GRP78), C/EBP-homologous protein 10 (CHOP10), and eukaryotic initiation factor 2 α (eIF2 α ) and signaling molecules such as phosphatidylinositol 3-kinase (PI3K), insulin receptor substrates-1 (IRS-1), and c-Jun N-terminal protein kinase (JNK) were investigated. WHW significantly inhibited the expression of XBP-1, GRP78, CHOP10, and eIF2 α in ER stress-induced 3T3-L1 adipocytes. WHW also increased the PI3K expression and the IRS-1 phosphorylation but decreased the phosphorylation of JNK in ER stress-induced 3T3-L1 adipocytes. Our results indicate that WHW inhibits ER stress in adipocytes by suppressing the expression of ER stress-mediated molecules and the insulin signaling pathway, suggesting that WHW may be an attractive therapeutic agent for managing T2D.

The roots of Atractylodes japonica Koidzumi promote adipogenic differentiation via activation of the insulin signaling pathway in 3T3-L1 cells.

BACKGROUND: Type 2 diabetes (T2D) is a complex metabolic disorder characterized by insulin resistance and hyperglycemia. Peroxisome proliferator-activated receptor gamma (PPARγ) is a key transcription factor and plays an important role in the regulation of genes involved in adipogenic differentiation, glucose metabolism and insulin signal transduction. METHODS: In this study, the effects of the root extract of Atractylodes japonica Koidzumi (Atractylodis Rhizoma Alba, ARA) on the differentiation of 3T3-L1 preadipocytes and the possible mechanism of glucose transport were investigated. 3T3-L1 cells were cultured with insulin and ARA extract. RESULTS: In 3T3-L1 cells, ARA extract significantly enhanced adipogenic differentiation and upregulated the expression of PPARγ genes and protein in a dose-dependent manner. ARA also promoted glucose transport by increasing the glucose transporter 4 (GLUT-4), phosphatidylinositol 3-kinase (PI3K) and insulin receptor substrates-1 (IRS-1) levels. CONCLUSION: Our results suggest that ARA extract may be an attractive therapeutic agent for managing T2D via promoting the differentiation of adipocytes with the upregulation of PPARγ levels and the activation of the insulin signaling pathway.

2,5-dihydroxyacetophenone isolated from Rehmanniae Radix Preparata inhibits inflammatory responses in lipopolysaccharide-stimulated RAW264.7 macrophages.

Rehmanniae Radix Preparata, the steamed root of Rehmannia glutinosa Libosch, has been widely used for the treatment of inflammatory conditions in Oriental medicines. In this study we evaluated the effects of 2,5-dihydroxyacetophenone (DHAP) isolated from Rehmanniae Radix Preparata on inflammatory responses in lipopolysaccharide (LPS)-stimulated RAW264.7 mouse macrophages. LPS-stimulated RAW264.7 cells were used to investigate the anti-inflammatory activity of DHAP on the production of inflammatory mediators such as nitric oxide (NO), inducible NO synthase (iNOS), tumor necrosis factor-α (TNF-α), and interleukin (IL)-6. DHAP significantly inhibited NO production via the suppression of iNOS expression and significantly decreased levels of the pro-inflammatory cytokines TNF-α and IL-6 via the down-regulation of their mRNA expression in LPS-stimulated RAW264.7 cells. DHAP potently inhibited the phosphorylation of extracellular signal-related kinase (ERK) 1/2 and the nuclear translocation of nuclear factor-κB (NF-κB) p65 in LPS-stimulated cells. These results indicate that DHAP inhibits the production of inflammatory mediators in activated macrophages by blocking the ERK1/2 and NF-κB signaling pathways. Our results suggest that DHAP from Rehmanniae Radix Preparata has anti-inflammatory activity in activated macrophages, raising the possibility that this compound has a therapeutic potential for inflammatory conditions.

Consumption of curcumin elevates fecal immunoglobulin A, an index of intestinal immune function, in rats fed a high-fat diet.

This study was conducted to elucidate the effects of dietary polyphenols on intestinal immunoglobulin A (IgA) response and mucin levels in rats fed a high-fat diet. In experiment 1, rats were fed a high-fat diet with or without several polyphenols including curcumin, rutin, D(+)-catechin, ellagic acid and quercetin at the level of 0.5%. Among the polyphenols examined, consumption of curcumin markedly elevated the level of IgA in feces and colon contents. In experiment 2, rats were fed a high-fat diet or a low-fat diet with or without 0.5% curcumin. Fecal level of IgA was higher in the high-fat diet group than in the low-fat diet group. In the rats fed the high-fat diet, dietary curcumin elevated fecal IgA, but not in those fed the low-fat diet. These results imply a novel effect of curcumin on intestinal IgA in animals fed a high-fat diet.

Inhibitory effect of curcumin on IMP dehydrogenase, the target for anticancer and antiviral chemotherapy agents.

Inosine monophosphate dehydrogenase (IMPDH), a rate-limiting enzyme in the de novo synthesis of guanine nucleotides, is a therapeutic target for anticancer and antiviral agents. Among the 15 different polyphenols examined, curcumin was found to have an inhibitory effect on the IMPDH activity in both a competitive and uncompetitive manner and to suppress the cellular GTP level in HT-29 colon carcinoma cells.

Consumption of some polyphenols reduces fecal deoxycholic acid and lithocholic acid, the secondary bile acids of risk factors of colon cancer.

This study was performed to examine the effect of dietary polyphenols on fecal secondary bile acids, such as deoxycholic acid and lithocholic acid, the risk factors of colon cancer, in rats fed a high-fat diet. In experiment 1, rats were fed a 30% beef tallow diet containing 0.5% polyphenols for 3 weeks. Dietary curcumin and caffeic acid significantly reduced the fecal concentration of deoxycholic acid. Dietary caffeic acid, catechin, rutin, and ellagic acid significantly reduced fecal lithocholic acid. Fecal hyodeoxycholic acid, a metabolite of lithocholic acid, was markedly lowered by dietary curcumin, caffeic acid, catechin, and rutin. In experiment 2, rats were fed a 30 or 5% beef tallow diet with or without the addition of 0.5% curcumin. In the rats without receiving curcumin, the fecal level of deoxycholic acid was significantly higher in the high-fat diet group than in the low-fat diet group. Fecal deoxycholic acid was significantly reduced by dietary curcumin in the high-fat diets but not in the low-fat diets. The results suggest novel effects of some polyphenols favorable for colon health by reducing secondary bile acids in animals fed a high-fat diet.