Investigation of the uptake and transport of polysaccharide from Se-enriched Grifola frondosa in Caco-2 cells model.

A variety of beneficial pharmacological activities have been reported for Se-enriched Grifola frondosa polysaccharides. However, little has been reported on its absorption, and its intestinal uptake and transport profiles remain unknown. Based on our previous research, the aim of this study was to investigate its absorption from two aspects - the polysaccharides and selenium of Se-enriched Grifola frondosa polysaccharides (Se-GFP-22) across Caco-2 cells in vitro. The Caco-2 cells monolayer culture model was successfully constructed to study the transport and uptake of Se-GFP-22. The results revealed that the uptake and transport of Se-GFP-22 were time- and concentration- dependent. Transport studies illustrated that Se-GFP-22 could penetrate Caco-2 cells, mainly mediated through the same routes as endocytosis and selenium in the organic selenium (Se-GFP-22) was more easily absorbed than that in the inorganic selenium control group (sodium selenite). The uptake of Se-GFP-22 may be a macropinocytosis pathway, which was an accumulation from cytoplasm to nucleus process. Se-GFP-22 was a moderately absorbed biological macromolecule testified by the apparent permeability coefficients (Papp) value and transport rates. This work illustrates the characteristics on uptake and transport of Se-GFP-22 and all these results may help to explore the mechanism of polysaccharide absorption in vitro.

Purification, structural elucidation and physicochemical properties of a polysaccharide from Abelmoschus esculentus L (okra) flowers.

Abelmoschus esculentus L (okra) is widely used as a healthy vegetable and favourable source of dietary medicine. Okra flowers which are by-products of okra, are rich in polysaccharide, polyphenols and trace elements etc., however, except a few for health tea, most of them were discarded as the waste of resources. In this study, a polysaccharide named AEFP22 was extracted, purified and identified from okra flowers, and its physicochemical property and antioxidant activity were also elucidated. AEFP22, with a molecular weight of 2.741 × 105 Da, was composed of Rha, GalA and Gal in the ratio of 1: 1.02: 0.86. The methylation and nuclear magnetic resonance (NMR) analysis indicated AEFP22 was composed of [2)-α-D-Rhap-(1 â†’ 4)-α-D-GalpA-(1 â†’ 2,4)-α-D-Rhap-(1 â†’ 4)-α-D-GalpA-(1] with branch of terminal T-α-D-Galp pointed at C4 of 1,2,4-α-D-Rhap. The Conge-red test, Atomic force microscope (AFM) and Scanning electron microscope (SEM) further revealed the triple-helical conformation, irregular sheet structure with molecule aggregations of AEFP22. The physicochemical property analysis indicated AEFP22 possessed stable thermal property and exhibited shear-thinning and normal Newtonian fluid in different concentrations, -7.04 mV zeta potential and polymerization phenomenon existed in AEFP22 solution. AEFP22 exhibited good 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability. These results indicated potential utilization of AEFP22 in nutritional food and material application.

Effect of chromium citrate on the mechanism of glucose transport and insulin resistance in Buffalo rat liver cells.

OBJECTIVE: Our published literature indicated that chromium citrate could regulate the glycemic index in alloxaninduced diabetic mice. The present study investigated the mechanism of chromium citrate in insulin resistance (IR) buffalo rat liver (BRL) cells. MATERIALS And METHODS: Chromium citrate was synthesized in our laboratory. BRL cells were purchased from the Chinese Academy of Sciences Cell Bank. The glucose transport and IR affected by chromium citrate in BRL cells were examined. The Thiazolyl Blue Tetrazolium Bromide (MTT) and glucose assay experiments were measured by microplate ELISA reader. The protein kinase B (Akt), glucose transporter-4 (Glut4), and phosphor-AMP-activated protein kinase ß1 levels were tested by Western blot, and the mRNA expression of glucose transport proteins (Akt2, Glut4, and AMPactivated protein kinase α2 (AMPKα2)) and insulin sensitivity proteins (insulin receptor substrate1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), and peroxisome proliferator-activated receptor γ (PPARγ)) was measured by reverse transcription-polymerase chain reaction. RESULTS: The results indicated that the glucose absorption level of chromium citrate groups was higher than model group significantly. It demonstrated that chromium citrate could significantly improve glucose absorption in IR BRL cells. The Akt, Glut4, and phosphor-AMPKß1 levels in chromium citrate groups (at doses of 0.4, 0.2, and 0.1 µg Cr/mL) were markedly improved when compared with the other experiment groups, and chromium citrate could more effectively increase the Akt level than chromium trichloride. In addition, the mRNA expression of Akt2, Glut4, and AMPKα2 in chromium citrate groups was significantly improved when contrasted with model group. CONCLUSION: The consequences illustrated that chromium citrate can affect the IR BRL cells' ameliorating glucose transport and IR.