Effect of the flavonol quercetin on ion transport in the isolated intestine of the eel, Anguilla anguilla

The impact of Morus alba L. leaf extract on intestinal ion transport. An in vitro study

Morus alba L. (White mulberry), is an important and popular herbal plant of the Moraceae family. It has been widely used due to its therapeutic properties, which include antidiabetic, antibacterial, anti-inflammatory, cardiovascular, and hypolpidemic activity. The present study evaluates the effects of aqueous white mulberry leaf extract on the transepithelial ion pathway in the rabbit colon epithelium (n = 48), using electrophysiological methods. In addition, the antioxidant potential and the chemical composition of the extract were determined. A mechanical-chemical stimulation with white mulberry in RH fluid (MB-RH) caused a statistically significant (p < 0.001) increase in the transepithelial electrical potential difference, from - 0.130 to - 0.685 mV. Gentle washing of the intestine with white mulberry in bumetanide, used as inhibitor of transepithelial chloride pathways, resulted in 14.8% shorter reaction than during MB-RH stimulation. There were no statistically significant differences between the electric potential values measured during stimulation with amiloride solution, used as inhibitor of transepithelial sodium pathways, and white mulberry in amilorid solution (p = 0.485). A short-term application of extract to the colon epithelium is responsible for local and reversible inhibition of chloride ion channels. The extract enhances sodium ion absorption and consequently changes the electrical potential. The effect of white mulberry extract on sodium ion transport may be related to the mechanism of hypoglycaemic activity of mulberry leaves.

New Stable Cell Lines Derived from the Proximal and Distal Intestine of Rainbow Trout (Oncorhynchus mykiss) Retain Several Properties Observed In Vivo

We derived two novel cell lines from rainbow trout (RT) proximal (RTpi-MI) and distal intestine (RTdi-MI) and compared them with the previously established continuous cell line RTgutGC. Intestinal stem cells, differentiating and differentiated epithelial cells, and connective cells were found in all cell lines. The cell lines formed a polarized barrier, which was not permeable to large molecules and absorbed proline and glucose. High seeding density induced their differentiation into more mature phenotypes, as indicated by the downregulation of intestinal stem cell-related genes (i.e., sox9, hopx and lgr5), whereas alkaline phosphatase activity was upregulated. Other enterocyte markers (i.e., sglt1 and pept1), however, were not regulated as expected. In all cell lines, the presence of a mixed population of epithelial and stromal cells was characterized for the first time. The expression by the stromal component of lgr5, a stem cell niche regulatory molecule, may explain why these lines proliferate stably in vitro. Although most parameters were conserved among the three cell lines, some significant differences were observed, suggesting that characteristics typical of each tract are partly conserved in vitro as well.

Plasma Protein Binding of Herbal-Flavonoids to Human Serum Albumin and Their Anti-proliferative Activities

Herbal-flavonoids (HF) as polyphenolic secondary metabolites are taken in the daily diet to join in many metabolic processes in the human organism. Anti-proliferative activities and human serum albumin (HSA) binding capacities of herbal-flavonoids namely 7,5'-dimethoxyisoetin (HF1), homoorientin-6''-4-O-methyl-myo-inositol (HF2), (2R, 3R)-(+)-dihydrokaempferol-7,4'-dimethylether (HF3), eriodictyol-7,4'-dimethylether (HF4) and flavonoids isoorientin (HF5) and genkwanin (HF6) were investigated. Anti-proliferative activities were determined by the xCELLigence system by treatment with human prostate (PC3) and cervical cancer (HeLa) cells. The binding capacities were studied by two-dimensional (2D-FL) and three-dimensional (3D-FL) fluorescence spectroscopy. HeLa and PC3 cell lines were treated with flavonoids at 10, 50 and 100 μg/mL concentrations over a 48 hour period. Stable anti-proliferative efficacy plots were obtained for tested flavonoids. From the flavonoids, HF3 and HF4 showed the strongest anti-proliferative effect against PC3 and HeLa cell line. HF1 and HF2 exhibited the strongest binding capacity to the HSA corresponding to Kb values of 3.81 x 104 M-1 and 6.00 x 104 M-1, respectively. The studies revealed that the flavonoids form the basis of in vivo preclinical studies as important nutraceuticals of the daily diet, as well as modelled in medical and pharmacological applications.

Rainbow Trout (Oncorhynchus Mykiss) Intestinal Epithelial Cells as a Model for Studying Gut Immune Function and Effects of Functional Feed Ingredients

The objective of this study was to evaluate the suitability of the rainbow trout intestinal epithelial cell line (RTgutGC) as an in vitro model for studies of gut immune function and effects of functional feed ingredients. Effects of lipopolysaccharide (LPS) and three functional feed ingredients [nucleotides, mannanoligosaccharides (MOS), and beta-glucans] were evaluated in RTgutGC cells grown on conventional culture plates and transwell membranes. Permeation of fluorescently-labeled albumin, transepithelial electrical resistance (TEER), and tight junction protein expression confirmed the barrier function of the cells. Brush border membrane enzyme activities [leucine aminopeptidase (LAP) and maltase] were detected in the RTgutGC cells but activity levels were not modulated by any of the exposures. Immune related genes were expressed at comparable relative basal levels as these in rainbow trout distal intestine. LPS produced markedly elevated gene expression levels of the pro-inflammatory cytokines il1b, il6, il8, and tnfa but had no effect on ROS production. Immunostaining demonstrated increased F-actin contents after LPS exposure. Among the functional feed ingredients, MOS seemed to be the most potent modulator of RTgutGC immune and barrier function. MOS significantly increased albumin permeation and il1b, il6, il8, tnfa, and tgfb expression, but suppressed ROS production, cell proliferation and myd88 expression. Induced levels of il1b and il8 were also observed after treatment with nucleotides and beta-glucans. For barrier function related genes, all treatments up-regulated the expression of cldn3 and suppressed cdh1 levels. Beta-glucans increased TEER levels and F-actin content. Collectively, the present study has provided new information on how functional ingredients commonly applied in aquafeeds can affect intestinal epithelial function in fish. Our findings suggest that RTgutGC cells possess characteristic features of functional intestinal epithelial cells indicating a potential for use as an efficient in vitro model to evaluate effects of bioactive feed ingredients on gut immune and barrier functions and their underlying cellular mechanisms.

Antithrombotic mechanism of polysaccharides in Blackberry (Rubus spp.) seeds

The blackberry seed was typically removed as a byproduct and waste from blackberry fruits for juices. Developing value-added utilization of berry seeds will significantly expand the market for berry products as well as improve benefit to berry producers. However, the research on blackberry seed is limited. The objective of this paper was to research antithrombotic mechanism of polysaccharides in blackberry seeds. Polysaccharides in blackberry seeds were extracted, purified and identified by high-performance gel permeation chromatography (HPSEC), gas chromatography (GC), fourier transform infrared (FT-IR) spectrometer and nuclear magnetic resonance spectra (NMR). Anticoagulant activities were evaluated in vivo by measuring activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), fibrinogen (FIB) and plasma recalcification time (RRT). Four polysaccharides named BSP-1a, BSP-1b, BSP-2 and BSP-3 were isolated from Blackberry (Rubus spp.) seeds. The results indicated that BSP-1b, BSP-2 and BSP-3 exhibited the anticoagulant activity. Therefore, the anti-thrombosis effects of BSP-1b, BSP-2 and BSP-3 were investigated in vivo by 6-Keto-PGF1α, thromboxane B2 (TXB2), endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), whole blood viscosity (WBV), plasma viscosity (PV), hematocrit (Hct), erythrocyte sedimentation rate (ESR), APTT, TT, PT and FIB. The results suggested that BSP-1b, BSP-2 and BSP-3 had the inhibition effect on thrombus formation, and the antithrombotic effects were associated with the regulation of vascular endothelium active substance, activating blood flow and anticoagulation effect.

Three months of Western diet induces small intestinal mucosa alteration in TLR KO mice

Several studies support the role of Western-style diet (WD) in inflammatory bowel disease (IBD). Toll-like receptors/NOD-like receptors (TLRs/NLRs) are important to maintain a healthy epithelium as well as inducing inflammation. Given that dietary factors influence IBD development, that epithelial dysfunction is thought to be involved in initiating intestinal inflammation and that TLR-NLR are involved in maintenance of the functionality of intestinal epithelium as well as in regulating inflammation, we decided to examine the role of TLR signals in the triggering events that lead to alteration of the small intestinal epithelium associated to consumption of WD. C57BL/6J mice deficient for TLR2, 4, 9, or NOD2 and wild-type (WT) were fed a WD or a standard diet for 3 months. The effects of WD on small intestinal samples were evaluated by histological and immunohistochemical analysis. After 3 months, WD modifies the morphology and the organization of the small intestine in TLR9 KO mice compared with WT mice and the others TLRs. The most interesting change involved the expression of proliferative and differentiation markers of WNT signaling, Ki67 and FzD5. Mice deficient in TLR2, 4, and NOD2 have a significant reduction in the proliferative cell numbers but do not show any signs of histological alterations. Our results suggest that TLR9 is an important protective factor in intestinal epithelial homeostasis and provide new insights into an unrecognized role of TLR9 signaling in the small intestinal mucosa dysfunction associated with WD.

Effects of quercetin and menadione on intestinal calcium absorption and the underlying mechanisms

Quercetin (QT) could be considered as a potential therapeutic agent for different diseases due to its antioxidant, anti-inflammatory, antiviral and anticancer properties. This study was designed to investigate the ability of QT to protect the chick intestine against menadione (MEN) induced injury in vivo and in vitro. Four-week old chicks (Gallus gallus) were treated i.p. with 2.5μmol of MEN/kg b.w. or with i.l. 50μM QT or both. QT protected the intestinal Ca(2+) absorption against the inhibition caused by MEN, but QT alone did not modify. Glutathione (GSH) depletion provoked by MEN in chick enterocytes was abolished by QT treatment, whereas QT alone did not modify the intestinal GSH content. The enhancement of GSH peroxidase activity produced by MEN was blocked by QT treatment. In contrast, superoxide dismutase activity remained high after simultaneous treatment of enterocytes with MEN and QT. The flavonol also avoided changes in the mitochondrial membrane permeability (swelling) produced by MEN. The FasL/Fas/caspase-3 pathway was activated by MEN, effect that was abrogated by QT. In conclusion, QT may be useful in preventing inhibition of chick intestinal Ca(2+) absorption caused by MEN or other substances that deplete GSH, by blocking the oxidative stress and the FasL/Fas/caspase-3 pathway activation.