pectins and galactomannan

Pumpkin polysaccharides have arrested researchers' attention in fields of food supplements for healthy product and traditional Chinese medicine due to their multiple bioactivities with non-toxic and highly biocompatible. This review emphatically summarized recent progresses in the primary and spatial structural features, various bioactivities, structure-to-function associations, different preparation techniques, and absorption characteristics across intestinal epithelial and in vivo bio-distribution of pumpkin polysaccharides. Additionally, current challenges and future trends in development of pumpkin polysaccharides were pointed out. We found that pumpkin polysaccharides were primary structure (e.g. glucan, galactoglucan, galactomannan, galactan, homogalacturonan (HG), and rhamnogalacturonan-Ι (RG-Ι)) and special structure diverse (e.g. hollow helix, linear, and sphere-like) and significant functional foods or therapeutic agents (e.g. oral hypoglycemic agents). Moreover, we found that the molecular weight (Mw), uronic acid, linkage types, and modifications all could affect their bioactivities (e.g. anti-oxidant, anti-coagulant, and anti-diabetic activities), and pumpkin polysaccharides may across intestinal epithelial into the blood reaching to target organs. Collectively, the structures diversity and pharmacological values of pumpkin polysaccharides support their therapeutic potentials and sanitarian functions.

Topics: Antioxidants; Cucurbita; Dietary Supplements; Functional Food; Galactans; Galactose; Glucans; Hypoglycemic Agents; Mannans; Medicine, Chinese Traditional; Pectins; Phytochemicals; Plant Extracts; Polysaccharides; Polysaccharides, Bacterial

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin-glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins' action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer.

Topics: Calixarenes; Clinical Trials as Topic; Galactose; Galectins; Humans; Mannans; Neoplasms; Pectins; Peptides; Polysaccharides; Thiogalactosides

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2-7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.

Topics: Dietary Fiber; Fructose; Galactose; Glucose; Hardness; Lignin; Mannans; Microscopy; Pectins; Phoeniceae; Sucrose; Xylans

Galactomannans derived from fenugreek confer known health benefits; however, there is little information regarding health benefits of citrus pectin (CP) and its association with gut microbiome metabolites. The aim of this study was to examine links between galactomannan and CP consumption, microbiota development, and glucose metabolism.. Male C57 BL/6 J mice ages 7 to 8 wk were fed ad libitum with a normal diet or one supplemented with 15% of either galactomannan or CP. At 3 wk, an oral glucose tolerance test was performed. Animals were sacrificed at 4 wk and relevant organs were harvested.. Fiber enrichment led to reductions in weight gain, fasting glucose levels, and total serum cholesterol (P < 0.05). Compared with mice fed the normal diet, microbiota populations were altered in both fiber groups and were found to be richer in Bacteroidetes rather than Firmicutes (P < 0.05). The modification was significantly greater in galactomannan-fed than in CP-fed mice (P < 0.0001). Also, enhanced levels of the short-chain fatty acid (SCFA) propionate were found in the cecal contents of CP-fed animals (P < 0.05). Protein expression levels of monocarboxylate transporter 1, which may promote transport of SCFA, were measured in the large intestines after fiber consumption. Enhanced adenosine monophosphate-activated protein kinase (AMPK) activation was observed in livers of galactomannan-fed mice (P < 0.05).. Consumption of diets containing soluble fibers, as used in this study, resulted in gut microbiota comprising a healthier flora, and led to positive effects on weight, glycemic control, and liver β oxidation via AMPK.

Topics: AMP-Activated Protein Kinases; Animals; Blood Glucose; Cecum; Diet; Dietary Fiber; Fatty Acids, Volatile; Galactose; Gastrointestinal Microbiome; Glucose Tolerance Test; Liver; Male; Mannans; Mice; Mice, Inbred C57BL; Pectins; Propionates; Trigonella

Galactomannan and citrus pectin are considered 'super fibers' known for altering gut microbiota composition and improving glucose and lipid metabolism. The study aims to investigate the fiber's effect on a nonalcoholic steatohepatitis (NASH) model.. Two feeding experiments are carried out using groups of 7-8 week-old male C57BL/6J mice. The diets used are based on a high cholesterol/cholate diet (HCD), such as a nutritional NASH model. Mice are fed a diet with or without 15% fiber-citrus pectin (HCD-CP) or galactomannan (HCD-G) together with the HCD (first experiment), which commenced 3 weeks prior to the HCD (second experiment). Liver damage is evaluated by histological and biochemical parameters. Galactomannan leads to lesser weight gain and improved glucose tolerance, but increased liver damage. This is shown by elevated levels of liver enzymes compared to that with HCD alone. Fibers induce higher steatosis, as evaluated by liver histology. This intriguing result is linked to various changes in the gut microbiota, such as elevated Proteobacteria levels in the galactomannan group, which are correlated with disturbed metabolism and dysbiosis.. In a NASH mouse model, galactomannan increases liver damage but improves glucose metabolism. Changes in the microbiota composition may answer this enigmatic observation.

Topics: Animals; Body Weight; Cholesterol; Diet, High-Fat; Dietary Fiber; Disease Models, Animal; Fatty Acids, Volatile; Galactose; Gastrointestinal Contents; Gastrointestinal Microbiome; Glucose Tolerance Test; Lipid Metabolism; Liver; Male; Mannans; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Pectins

Some complex plant-derived polysaccharides, such as modified citrus pectins and galactomannans, have been shown to have promising anti-inflammatory and anti-cancer effects. Most reports propose or claim that these effects are due to interaction of the polysaccharides with galectins because the polysaccharides contain galactose-containing side chains that might bind this class of lectin. However, their direct binding to and/or inhibition of the evolutionarily conserved galactoside-binding site of galectins has not been demonstrated. Using a well established fluorescence anisotropy assay, we tested the direct interaction of several such polysaccharides with physiological concentrations of a panel of galectins. The bioactive pectic samples tested were very poor inhibitors of the canonical galactoside-binding site for the tested galectins, with IC50 values >10 mg/ml for a few or in most cases no inhibitory activity at all. The galactomannan Davanat® was more active, albeit not a strong inhibitor (IC50 values ranging from 3 to 20 mg/ml depending on the galectin). Pure synthetic oligosaccharide fragments found in the side chains and backbone of pectins and galactomannans were additionally tested. The most commonly found galactan configuration in pectins had no inhibition of the galectins tested. Galactosylated tri- and pentamannosides, representing the structure of Davanat®, had an inhibitory effect of galectins comparable with that of free galactose. Further evaluation using cell-based assays, indirectly linked to galectin-3 inhibition, showed no inhibition of galectin-3 by the polysaccharides. These data suggest that the physiological effects of these plant polysaccharides are not due to inhibition of the canonical galectin carbohydrate-binding site.

Topics: Antineoplastic Agents; Binding Sites; Cell Line, Tumor; Drug Screening Assays, Antitumor; Fluorescence Polarization; Galactose; Galectins; Hemagglutination; Humans; Inhibitory Concentration 50; Mannans; Pectins; Polysaccharides; Protein Binding

Chemical analyses and glycome profiling demonstrate differences in the structures of the xyloglucan, galactomannan, glucuronoxylan, and rhamnogalacturonan I isolated from soybean ( Glycine max ) roots and root hair cell walls. The root hair is a plant cell that extends only at its tip. All other root cells have the ability to grow in different directions (diffuse growth). Although both growth modes require controlled expansion of the cell wall, the types and structures of polysaccharides in the walls of diffuse and tip-growing cells from the same plant have not been determined. Soybean (Glycine max) is one of the few plants whose root hairs can be isolated in amounts sufficient for cell wall chemical characterization. Here, we describe the structural features of rhamnogalacturonan I, rhamnogalacturonan II, xyloglucan, glucomannan, and 4-O-methyl glucuronoxylan present in the cell walls of soybean root hairs and roots stripped of root hairs. Irrespective of cell type, rhamnogalacturonan II exists as a dimer that is cross-linked by a borate ester. Root hair rhamnogalacturonan I contains more neutral oligosaccharide side chains than its root counterpart. At least 90% of the glucuronic acid is 4-O-methylated in root glucuronoxylan. Only 50% of this glycose is 4-O-methylated in the root hair counterpart. Mono O-acetylated fucose-containing subunits account for at least 60% of the neutral xyloglucan from root and root hair walls. By contrast, a galacturonic acid-containing xyloglucan was detected only in root hair cell walls. Soybean homologs of the Arabidopsis xyloglucan-specific galacturonosyltransferase are highly expressed only in root hairs. A mannose-rich polysaccharide was also detected only in root hair cell walls. Our data demonstrate that the walls of tip-growing root hairs cells have structural features that distinguish them from the walls of other roots cells.

Topics: Cell Wall; Galactose; Glucans; Glycine max; Mannans; Pectins; Plant Roots; Xylans

Galectin-3 protein is critical to the development of liver fibrosis because galectin-3 null mice have attenuated fibrosis after liver injury. Therefore, we examined the ability of novel complex carbohydrate galectin inhibitors to treat toxin-induced fibrosis and cirrhosis. Fibrosis was induced in rats by intraperitoneal injections with thioacetamide (TAA) and groups were treated with vehicle, GR-MD-02 (galactoarabino-rhamnogalaturonan) or GM-CT-01 (galactomannan). In initial experiments, 4 weeks of treatment with GR-MD-02 following completion of 8 weeks of TAA significantly reduced collagen content by almost 50% based on Sirius red staining. Rats were then exposed to more intense and longer TAA treatment, which included either GR-MD-02 or GM-CT-01 during weeks 8 through 11. TAA rats treated with vehicle developed extensive fibrosis and pathological stage 6 Ishak fibrosis, or cirrhosis. Treatment with either GR-MD-02 (90 mg/kg ip) or GM-CT-01 (180 mg/kg ip) given once weekly during weeks 8-11 led to marked reduction in fibrosis with reduction in portal and septal galectin-3 positive macrophages and reduction in portal pressure. Vehicle-treated animals had cirrhosis whereas in the treated animals the fibrosis stage was significantly reduced, with evidence of resolved or resolving cirrhosis and reduced portal inflammation and ballooning. In this model of toxin-induced liver fibrosis, treatment with two galectin protein inhibitors with different chemical compositions significantly reduced fibrosis, reversed cirrhosis, reduced galectin-3 expressing portal and septal macrophages, and reduced portal pressure. These findings suggest a potential role of these drugs in human liver fibrosis and cirrhosis.

Topics: Animals; Apoptosis; Blotting, Western; Cell Line; Cell Proliferation; Fibrosis; Galactans; Galactose; Galectins; Humans; Liver Cirrhosis; Liver Diseases; Male; Mannans; Pectins; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Thioacetamide

The thermophilic fungi Thermomyces lanuginosus, Malbranchea cinnamomea, Myceliophthora fergusii and the thermotolerant Aspergillus terreus were cultivated on various carbon sources, and hemicellulolytic and cellulolytic enzyme profiles were evaluated. All fungi could grow on locust bean galactomannan (LBG), Solka floc, wheat bran and pectin, except T. lanuginosus, which failed to utilize LBG for growth. Different levels of cellulase and hemicellulase activities were produced by these fungal strains. Depending on the carbon source, variable ratios of thermostable hydrolytic enzymes were obtained, which may be useful in various applications. All strains were found to secrete xylanolytic and mannanolytic enzymes. Generally, LBG was the most efficient carbon source to induce mannanase activities, although T. lanuginosus was able to produce mannanase only on wheat bran as a carbon source. Xylanolytic activities were usually highest on wheat bran medium, but in contrast to other investigated fungi, xylanase production by M. fergusii was enhanced on pectin medium. Preliminary thermostability screening indicated that among the investigated species, thermotolerant glycosidases can be found. Some of the accessory activities, including the α-arabinosidase activity, were surprisingly high. The capability of the produced enzymes to improve the hydrolysis of lignocellulosic pretreated substrate was evaluated and revealed potential for these enzymes.

Topics: Carbon; Dietary Fiber; Fungi; Galactose; Glycoside Hydrolases; Hot Temperature; Mannans; Pectins

The Pulsed Field Gradient Spin-Echo (PFG-SE) method was used to study the diffusional properties of water in guar galactomannan solutions and in highly methyl-esterified (HDE) pectin solutions and gels. The diffusion coefficient of water in the non-gelling galactomannan system was the same than that of pure water and independent on polymer concentration, despite of a strong increase in viscosity. In the two-component gelling system, pectin-sucrose, the diffusion coefficient of water was lower than in the pure state, and decreasing as a function of the concentration of both constituents. A normalized diffusion coefficient, Dgel/Dsuc, was defined to discriminate the effect of the gelation process on water diffusion, and it showed a clear dependence on the extent of network formation. Unrestricted diffusion was evidenced in all cases.

Topics: Diffusion; Galactose; Magnetic Resonance Spectroscopy; Mannans; Pectins; Polysaccharides; Water

Wistar rat jejunal disaccharidases were measured after feeding low fat, low fat + 5% pectin, low fat + 0.4% galactomannan, high fat, high fat + 5% pectin and high fat + 0.4% galactomannan diets for 16 weeks. All rats fed high fat diet had significantly lower jejunal sucrase and maltase levels when compared with their respective low fat groups. Lactase was significantly lowered in the high fat pectin group compared with the low fat pectin group, but was not significantly different when comparing the high fat or high fat galactomannan with their respective low fat groups. There was no significant difference in lactase, sucrase or maltase levels between the low fat groups, or between the high fat groups. We conclude that in Wistar rats an increased dietary fat level lowers jejunal sucrase, maltase and lactase levels, while the gel-forming substances pectin and galactomannan added at the levels of 5% and 0.4%, respectively, have no effect.

Topics: alpha-Glucosidases; Animals; beta-Galactosidase; Dietary Fats; Disaccharidases; Female; Galactose; Galactosidases; Jejunum; Mannans; Pectins; Polysaccharides; Random Allocation; Rats; Rats, Inbred Strains; Sucrase

Rat jejunal disaccharidases were measured after feeding high fat fibre-free, high fat pectin, high fat cellulose, high fat galactomannan and high fat tannin diets for 27 weeks. Compared with the high fat fibre-free diet, pectin lowered both lactase and sucrase levels (p less than 0.025). Galactomannan and tannin lowered only the lactase level (p less than 0.05), while cellulose had no significant effect on disaccharidase levels. These data suggest that dietary fibre components have individual and specific effects on jejunal disaccharidase levels, in the presence of a high fat diet.

Topics: alpha-Glucosidases; Animals; beta-Galactosidase; Cellulose; Dietary Fats; Dietary Fiber; Female; Galactose; Galactosidases; Glucosidases; Intestinal Mucosa; Jejunum; Male; Mannans; Pectins; Rats; Sucrase; Tannins