No abstract

Although epidemiological data have indicated that a strong negative association exists between coffee consumption and the prevalence of obesity-associated diseases, the molecular mechanisms by which coffee intake prevents obesity-associated diseases has not yet been elucidated. In this study, we found that coffee intake significantly suppressed high-fat diet (HFD)-induced metabolic alternations such as increases in body weight and the accumulation of adipose tissue, and up-regulation of glucose, free fatty acid, total cholesterol and insulin levels in the blood. We also found that coffee extract significantly inhibited adipogenesis in 3T3-L1 preadipocytes. In the early phase of adipogenesis, 3T3-L1 cells treated with coffee extract displayed the retardation of cell cycle entry into the G2/M phase called as mitotic clonal expansion (MCE). Coffee extract also inhibited the activation of CCAAT/enhancer-binding protein β (C/EBPβ) by preventing its phosphorylation by ERK. Furthermore, the coffee extract suppressed the adipogenesis-related events such as MCE and C/EBPβ activation through the down-regulation of insulin receptor substrate 1 (IRS1). The stability of the IRS1 protein was markedly decreased by the treatment with coffee extract due to proteasomal degradation. These results have revealed an anti-adipogenic function for coffee intake and identified IRS1 as a novel target for coffee extract in adipogenesis.

Recent epidemiological studies showed that coffee consumption is associated with a lower risk of type 2 diabetes, presumably due to suppression of excess fat accumulation in adipocytes. However, the mechanism underlying the effect of coffee on adipocyte differentiation has not been well documented. To elucidate the mechanism, we investigated the effect of coffee on the differentiation of mouse preadipocyte 3T3-L1 cells. Coffee reduced the accumulation of lipids during adipocytic differentiation of 3T3-L1 cells. At 5% coffee, the accumulation of lipids decreased to half that of the control. Coffee also inhibited the expression of the peroxisome proliferator-activated receptor γ (PPARγ), a transcription factor controlling the differentiation of adipocytes. Furthermore, coffee reduced the expression of other differentiation marker genes, aP2, adiponectin, CCAAT-enhancer-binding protein α (C/EBPα), glucose transporter 4 (GLUT4), and lipoprotein lipase (LPL), during adipocyte differentiation. Major bioactive constituents in coffee extracts, such as caffeine, trigonelline, chlorogenic acid, and caffeic acid, showed no effect on PPARγ gene expression. The inhibitory activity was produced by the roasting of the coffee beans.

No abstract

Cytosolic sulfotransferases (SULTs) are phase II drug-metabolizing enzymes that catalyze the transfer of a sulfonate group from 3Ј-phosphoadenosine 5Ј-phosphosulfate (PAPS) to molecules possessing phenols, enols, alcohols or amines. Sulfo-conjugation confers greater polarity and water solubility on the parent molecules, thereby facilitating biliary or urinary excretion and detoxification.

No abstract

Coffee is a complex mixture of many bioactive compounds possessing anti-inflammatory properties. However, the mechanisms by which coffee exerts anti-inflammatory effects remains unclear and the active ingredients have not yet been identified. In this study, we found that coffee extract at more than 2.5%(v/v) significantly inhibited LPS-induced inflammatory responses in RAW264.7 cells and that antiinflammatory activity of coffee required the roasting process. Interestingly, we identified pyrocatechol, a degradation product derived from chlorogenic acid during roasting, as the active ingredient exhibiting anti-inflammatory activity in coffee. HPLC analysis showed that 124 μM pyrocatechol was included in 100% (v/v) roasted coffee. A treatment with 5%(v/v) coffee extract and more than 2.5 μM pyrocatechol inhibited the LPS-induced activation of NF-κB and also significantly activated Nrf2, which acts as a negative regulator in LPS-induced inflammation. Furthermore, intake of 60% (v/v) coffee extract and 74.4 μM pyrocatechol, which is the concentration equal to contained in 60% (v/v) coffee, markedly inhibited the LPS-induced inflammatory responses in mice. Collectively, these results demonstrated that pyrocatechol, which was formed by the roasting of coffee green beans, is one of the ingredients contributing to the anti-inflammatory activity of coffee.

Turmeric is the powdered dry rhizome of the plant Curcuma longa and has been widely used as a coloring agent, as a spice and has been utilized in the treatment of inflammatory conditions and other diseases.1) Curcumin is a yellow pigment and is the major anti-oxidant and anti-inflammatory constituent of turmeric. It is present in curry and mustard, and it is used extensively in Asian countries and in traditional medicines. Curcumin and/or turmeric have both been shown to possess cancer chemopreventive activity in addition to anti-inflammatory activity, and these compounds have thus generated considerable attention as alternative medicines in recent years.2-4) The low incidence of colon cancer in Asian countries could be related to low meat intake, but may also be due to the regular use of turmeric in the diet of these regions. As the colon is exposed to turmeric and curcumin, it is a likely target for the anticarcinogenic activity of these compounds. Moreover, since these agents are often administered in combination with conventional therapeutic drugs, it is very important to further explore the potential benefits of herb-drug interactions. Previously we have investigated such herb-drug interactions at the level of conjugation. 5,6) We have also recently established an assay system for conjugation reactions of 1-naphthol using a human adenocarcinoma cell line, Caco-2.7) In our current study, to elucidate the possible interaction of both turmeric and curcumin with the conjugation pathways in cells, which in many cases are involved in the activation of procarcinogens, we measured their effects on the conjugation activity of 1-naphthol in Caco-2 cells. MATERIALS AND METHODS MaterialsPowdered turmeric was obtained from Wako, Ltd. and curcumin was purchased from Sigma. Water-soluble and DMSO-soluble turmeric solutions were prepared by stirring turmeric powder (10 g) in either 100 ml distilled water or DMSO for 3 h at room temperature. Each solution was then filtered.Cell Culture Human adenocarcinoma Caco-2 cells were grown in 12-well plates in 1 ml minimal essential medium (MEM) supplemented with 10% fetal bovine serum and additional non-essential amino acids. The cells were seeded at 5ϫ10 5 cells/ml and cultured for up to 3 weeks with medium changes every 4-5 d.Analyses of 1-Naphthyl Sulfates and Glucuronide 1-Naphthol (200 mM) was added to the culture medium and the cells were further incubated at 37°C. Aliquots of 50 ml of medium were removed at various times, and 30 ml of each of these samples was then filtered and injected into a HPLC apparatus, equipped with an ODS column (Chromolith Performance RP-18e, 100ϫ4.6 mm, Merck). The mobile phase consisted of 2 mM tetrabutylammonium hydrogen sulfate in water and acetonitrile (65 : 35). The flow rate was 1.0 ml/min with a column temperature of 40°C and elution was monitored at 285 nm. The retention times for 1-naphthol, 1-naphthyl sulfate and 1-naphthyl glucuronide were determined to be 19.0 min, 17.6 min and 4.6 min, respectively. The effects of curcumin or turmeric o...