James Swi-Bea Wu

Effects of caffeic acid and cinnamic acid on glucose uptake in insulin-resistant mouse hepatocytes

Tumor necrosis factor-alpha was used to induce insulin resistance of mouse liver FL83B cells. Two phenolic acids, caffeic acid and cinnamic acid, were then added separately to investigate their effects on glucose uptake of the insulin-resistant cells. The results suggest that these two phenolic acids may promote insulin receptor tyrosyl phosphorylation, up-regulate the expression of insulin signal associated proteins, including insulin receptor, phosphatidylinositol-3 kinase, glycogen synthase, and glucose transporter-2, increase the uptake of glucose, and alleviate insulin resistance in cells as a consequence.

Flow properties of fruit fillings

Abstract The flow properties of the fluid portion of fruit fillings were assessed to investigate the effects of gums. Results indicated that the shear rate–shear stress relations of the fluid portion of commercial fruit fillings and the model fillings made of waxy corn starch, fructose, citrate buffer, and a gum which could be guar gum, locust bean gum, CMC, xanthan gum or κ-carrageenan, fit well into the Herschel–Bulkley equation for pseudoplastic fluids. The fluid portion of the commercial fruit fillings was characterized with a yield stress between 39–51 Pa, a consistency index between 52–104 Pa·sn, and a flow index (n) around 0.4. In addition, the shear rate–shear stress relations could be fitted into a modified Herschel–Bulkley equation with a flow index fixed at 0.4. Addition of guar gum, locust bean gum and CMC increased while xanthan gum and κ-carrageenan decreased the consistency and flow indices in the modified Herschel–Bulkley equation. The effect of gum addition on the apparent viscosity of model fillings varies with the type of gum, amount of addition, and shear rate.

Protective Effect of Vanillic Acid against Hyperinsulinemia, Hyperglycemia and Hyperlipidemia via Alleviating Hepatic Insulin Resistance and Inflammation in High-Fat Diet (HFD)-Fed Rats

Excess free fatty acid accumulation from abnormal lipid metabolism results in the insulin resistance in peripheral cells, subsequently causing hyperinsulinemia, hyperglycemia and/or hyperlipidemia in diabetes mellitus (DM) patients. Herein, we investigated the effect of phenolic acids on glucose uptake in an insulin-resistant cell-culture model and on hepatic insulin resistance and inflammation in rats fed a high-fat diet (HFD). The results show that vanillic acid (VA) demonstrated the highest glucose uptake ability among all tested phenolic acids in insulin-resistant FL83B mouse hepatocytes. Furthermore, rats fed HFD for 16 weeks were orally administered with VA daily (30 mg/kg body weight) at weeks 13–16. The results show that levels of serum insulin, glucose, triglyceride, and free fatty acid were significantly decreased in VA-treated HFD rats (p < 0.05), indicating the protective effects of VA against hyperinsulinemia, hyperglycemia and hyperlipidemia in HFD rats. Moreover, VA significantly reduced values of area under the curve for glucose (AUCglucose) in oral glucose tolerance test and homeostasis model assessment-insulin resistance (HOMA-IR) index, suggesting the improving effect on glucose tolerance and insulin resistance in HFD rats. The Western blot analysis revealed that VA significantly up-regulated expression of hepatic insulin-signaling and lipid metabolism-related protein, including insulin receptor, phosphatidylinositol-3 kinase, glucose transporter 2, and phosphorylated acetyl CoA carboxylase in HFD rats. VA also significantly down-regulated hepatic inflammation-related proteins, including cyclooxygenase-2 and monocyte chemoattractant protein-1 expressions in HFD rats. These results indicate that VA might ameliorate insulin resistance via improving hepatic insulin signaling and alleviating inflammation pathways in HFD rats. These findings also suggest the potential of VA in preventing the progression of DM.

A glycoprotein extracted from golden oyster mushroom Pleurotus citrinopileatus exhibiting growth inhibitory effect against U937 leukemia cells.

Mushrooms have become popular sources of natural antitumor, antiviral, antibacterial, antioxidative, and immunomodulatory agents. Golden oyster mushroom, Pleurotus citrinopileatus , is a common mushroom in oriental countries for human consumption. We isolated a functional protein (PCP-3A) from the fresh fruiting body of this mushroom. The isolation procedure included ammonium sulfate fractionation, DEAE-Sepharose CL-6B ion exchange chromatography, and Sephacryl S-300 gel filtration. Electrophoresis demonstrated that PCP-3A is a glycoprotein composed of 10 subunits, each approximately 45.0 kDa in size. In vitro cell study showed that PCP-3A at a concentration about 12.5 microg/mL inhibits the proliferation of human tumor cell line U937, in a time- dependent manner (24, 48, and 72 h). It failed to agglutinate rabbit and human erythrocytes, excluding its possibility from being a lectin. Flow cytometry revealed that it is capable of inhibiting the growth of U937 cells by way of S phase arrest and apoptotic induction. We suggest that PCP-3A is worth further investigating for antitumor use.

In vitro antitumor and immunomodulatory effects of the protein PCP-3A from mushroom Pleurotus citrinopileatus.

A nonlectin glycoprotein (PCP-3A) newly isolated from the fruit body of edible golden oyster mushroom Pleurotus citrinopileatus has been shown to be growth inhibitory against human myeloid leukemic U937 cells in a previous report. There is a well-recognized relation between antitumor activity and immunomodulation. The immunomodulatory activity of PCP-3A was therefore assessed in the present study. Human mononuclear cells (MNC) and the CD4(+) T lymphocytes isolated from them were stimulated separately with PCP-3A for various durations and then filtered to obtain the conditioned media (CM). The conditioned medium from MNC (MNC-CM) was proved effective in inhibiting the growth of U937 cells. Increased secretion of cytokines TNF-α, IL-2, and IFN-γ from the stimulated MNC and CD4(+) T cells was found in CM. The antibody neutralization test of MNC-CM revealed that the growth inhibition on leukemic U937 cells was related to the elevation in cytokine concentration. We propose that PCP-3A stimulated human MNC to secrete cytokines TNF-α, IL-2, and IFN-γ, which subsequently inhibit the growth of U937 cells, and that PCP-3A may be a possible material for developing into an antileukemia ingredient in health food.

A novel glycoprotein from mushroom Hypsizygus marmoreus (Peck) Bigelow with growth inhibitory effect against human leukaemic U937 cells

This study was to isolate the anti-leukaemic component from edible mushroom Hypsizygus marmoreus (Peck) Bigelow. Crude protein was extracted from the basidioma, and then purified with DEAE-Sepharose CL-6B ion exchange chromatography followed by Sephacryl S-300 gel filtration. A protein which exerted high growth inhibitory effect on human leukaemic U937 cells and sufficient toxicological safety on normal human white blood cells was isolated and named HM-3A. Electrophoresis showed HM-3A approximately 52kDa in size. N-terminal analysis found the amino acid sequence ATTQWKTSAA and confirmed HM-3A a novel protein. High-performance anion-exchange column chromatography revealed HM-3A a glycoprotein with galactose as the major monosaccharide. Haemagglutination assay proved it non-lectin. We suggest that HM-3A is worth further investigation for antitumour use.

Degradation of Ascorbic Acid in Ethanolic Solutions

Ascorbic acid occurs naturally in many wine-making fruits. The industry also uses ascorbic acid as an antioxidant and color stabilizer in the making of alcoholic beverages including white wine, wine cooler, alcopop, and fruit liqueur. However, the degradation of ascorbic acid itself may cause browning and the deterioration of color quality. This study was aimed to monitor the degradation of ascorbic acid, the formation of degradation products, and the browning in storage of ascorbic acid containing 0-40% (v/v) ethanolic solutions buffered at pH 3.2 as models of alcoholic beverages. The results show that ascorbic acid degradation in the ethanolic solutions during storage follows first-order reaction, that the degradation and browning rates increase with the increase of ethanol concentration, that the activation energy for the degradation of ascorbic acid is in the range 10.35-23.10 (kcal/mol), that 3-hydroxy-2-pyrone is an indicator and a major product of ascorbic acid degradation, and that aerobic degradation pathway dominants over anaerobic pathway in ascorbic acid degradation in ethanolic solutions.

Inhibitory effect of a glycoprotein isolated from golden oyster mushroom ( Pleurotus citrinopileatus ) on the lipopolysaccharide-induced inflammatory reaction in RAW 264.7 macrophage.

Mushrooms have become an important source of natural antitumor, antiviral, antibacterial, immunomodulatory, and anti-inflammatory agents. Golden oyster mushroom, Pleurotus citrinopileatus , is a common mushroom in oriental countries for human consumption. The present study investigated the anti-inflammatory reaction of the bioactive nonlectin glycoprotein (PCP-3A) isolated from the fresh fruiting body of this mushroom. Western blot analysis on LPS-induced iNOS, COX-2, and NF-κB expressions in RAW 264.7 cells as affected by PCP3-A was performed to elucidate the mechanism of NO and PGE2 reduction. The results showed that PCP-3A failed to affect RAW 264.7 viability at a concentration up to 6.25 μg/mL, but inhibited LPS (1 μg/mL)-induced expression, and that PCP-3A inhibited the production of NO and PGE2 in LPS-activated macrophages via the down-regulation of certain pro-inflammatory mediators, including iNOS and NF-κB.

Effects of particle radius, fluid viscosity and relative velocity on the surface heat transfer coefficient of spherical particles at low Reynolds numbers

The temperature profile in spherical alginate particles during heating in fluids was monitored. The surface heat transfer coefficient (hfp) at the interface between fluid and particles was then evaluated analytically. The results show that hfps in this system range from 165 W m−3 °C−1 to 2376 W m−2 °C−1 when the radius of particles is between 0.0025 m and 0.0088 m, the viscosity of the fluid is between 0.00033 poise and 0.038 poise, and the relative velocity is set below 0.0025 m s−1. These results correspond to Nusselt numbers (Nu) in the range between 2.01 and 55.10, particle Reynolds numbers (Re) smaller than 106.1, Prandtl numbers (Pr) in the range between 2.27 and 260.7, and Grashof numbers (Gr) in the range between 1.54 × 103 and 1.82 × 108. Data analysis shows that the relations between dimensionless parameters follow the linear regression equation: ln(Nu Re−2) = 2.1396 ln(Re−1Pf0.55Gr0.45) − 11.4282. The results also reveal the importance of free convection in liquid/solid heat transfer at low Re.

A study on the mechanism of browning in mei liqueur using model solutions

Browning mechanisms of mei liqueur were studied using model solutions containing 28% ethanol in 0.1 M citrate solution (pH 3.0). Catechin alone was stable in the model solution but degraded rapidly to form hydroxymethyl furfural (HMF) in incubation with fructose at 70 °C. The rate of increase in the absorbance at 420 nm also suggested that fructose was more potent than glucose in enhancing browning in acidic ethanolic environment. We propose that the major browning mechanisms in mei liqueur are the oxidation and condensation of tannins and the interactions between tannins and HMF derived from fructose, rather than Maillard reaction, ascorbic acid degradation, or caramelization.