Polysaccharides

Dermatan sulphate is a glycosaminoglycan found in skin, blood vessels, heart valves, tendons, aorta, spleen and brain and is usually isolated from pig skin or beef lung tissue. The disaccharide repeat unit is composed of L-iduronic acid and N-acetyl-galactosamine-4-sulphate linked β-(1,3) and β-(1,4). There are also small amounts of D-glucuronic acid.

The main cell-wall components of baker’s yeast (Saccharomyces cerevisiae) as well as β-glucan are mannans with an α-1,6 mannose backbone and α-1,2 and α-1,3 mannose branches. The image was kindly provided by Dr. Chris Lawson.

Glycogen is a highly branched polysaccharide of glucose that serves as a form of energy storage in animals and fungi. It is the main storage form of glucose in the body.  In humans, glycogen is made and stored primarily in liver and muscle cells and functions as the second most important energy storage molecule to fat which is held in adipose tissue. Glycogen is analogous to starch and has a structure similar to amylopectin, but is more extensively branched and compact than starch. It occurs as granules in the cytosol/cytoplasm in many cell types, and plays an important role in the glucose cycle.

Glycogen is a highly branched polysaccharide of glucose that serves as a form of energy storage in animals and fungi. It is the main storage form of glucose in the body.  In humans, glycogen is made and stored primarily in liver and muscle cells and functions as the second most important energy storage molecule to fat which is held in adipose tissue. Glycogen is analogous to starch and has a structure similar to amylopectin, but is more extensively branched and compact than starch. It occurs as granules in the cytosol/cytoplasm in many cell types, and plays an important role in the glucose cycle.

PolyGlycopleX (PGX) is produced from a mixture containing proprietary proportions of three polysaccharides, konjac glucomannan, xanthan gum and sodium alginate.  Recent hydrodynamic, rheological and analytical studies have shown that the unexpectedly high viscosity of solutions of PGX is consistent with an interaction between a konjac glucomannan, xanthan gum complex and sodium alginate to form a new, ternary complex in solution. Human and animal feeding studies have shown that PGX can be used to control weight, lower the glycaemic index of foods and postprandial glycaemia.

Methyl cellulose is a water-soluble polymer that is used as a binder or thickener in pharmaceutical, food, and ceramic processing applications. Methylcellulose has an unusual lower critical solution temperature (LCST) between 40 °C and 50 °C. At temperatures below the LCST it is readily soluble in water; above the LCST it is not soluble, which has a paradoxical effect that heating a saturated solution of methylcellulose will turn it solid, because methylcellulose will precipitate out. The temperature at which this occurs depends on DS-value, with higher DS-values giving lower solubility and lower precipitation temperatures because the polar hydroxyl groups are masked.

Ethyl cellulose is similar in structure to methyl cellulose with ethyl replacing the methyl groups. It is approved for use in regulated markets such as food and pharmaceuticals. In pharmaceuticals it can mask the taste of bitter actives, enhance the strength and appearance of tablets and capsules, and enable controlled release formulations. In food products it functions as a binder, film former and flavour fixative.

β-1,3-Glucan is a carbohydrate compound that exhibits antioxidant activity. It has been shown to inhibit lipid peroxidation and protect cells from oxidative damage. β-1,3-Glucan is derived from various sources such as cellulose and biomass and can be extracted using methods like chloroform extraction. This compound has potential industrial applications in fields such as pharmaceuticals, where it can be used as an excipient or drug delivery agent. Additionally, β-1,3-Glucan has shown promise in agricultural applications due to its ability to enhance plant growth and stimulate the immune system of plants. Research has also indicated that this compound may have antimicrobial properties against certain pathogens. Molecular docking studies have revealed interactions between β-1,3-Glucan and other molecules such as prasugrel, indole-3-acetic acid, resiquimod, and sulfadiazine, suggesting potential synergistic effects or therapeutic applications. Overall, β

Sodium carboxymethyl dextran is a white, odourless and tasteless powder, which is freely soluble in water or electrolyte solutions. Applications that have been described for carboxymethyl dextran include carriers of paramagnetic contrast agents, preparation of conjugates of pharmacologically active compounds and carboxymethyl dextrans in biosensors.  A number of other uses in cosmetics, agriculture, foods, paints and textiles have been the subject of patent applications.

Dextran is α-(1,6)-linked α-D-glucan with α-(1,3)-linked glucose branch points produced by fermentation of Leuconostoc mesenteroides via the action of the enzyme dextransucrase on sucrose.  The main use for native dextran is as an extender in blood transfusions and products having a range of sharp cutoff molecular weights are produced commercially for this and other applications.  A complex of iron with dextran, known as iron dextran, is used as a source of iron for baby piglets which are often anaemic at birth.

Water thickener; rheological control additive; has industrial appplications

Chitosan is the deacetylated form of chitin.  The polysaccharide is deacetylated in order to render it soluble, which is then possible at pH values of less than 7 (normally in dilute acid).  This then allows the material to be used in a number of industrial applications as a binder and film former.

Dextran sulphate is a dextran derivative whose ulcer (colitis) -causing properties were first reported in hamsters and extrapolated a few years later to mice and rats. The exact mechanisms through which dextran sulphate induces intestinal inflammation are unclear but may be the result of direct damage of the monolayer of epithelial cells in the colon, leading to the crossing of intestinal contents (for e.g. commensal bacteria and their products) into underlying tissue and therefore induction of inflammation.  The dextran sulphate sodium induced ulceration model in laboratory animals has some advantages, when compared to other animal models of colitis, due to its simplicity and similarities to human inflammatory bowel disease.

Inulin is a prebiotic dietary fibre with a mildly sweet taste that promotes digestive health by supporting growth of healthy and balanced microbiota. In diagnostics, inulin is used for determining the glomerular filtration rate in functional kidney testing. Chemically, inulin is a chain of fructose molecules terminated at the reducing end with glucose. Thus, inulin is a fructan consisting of linear chains of β-(2,1) linked fructose residues, terminated at the reducing end by an α-D-(1,2)-glucopyranoside moiety.  It has a degree of polymerization typically between 2 and 60 (5). The β-(2,1) bond in inulin resists digestion in the gastrointestinal tract and is therefore responsible for its lower caloric value and beneficial effects on colon microbiota. A more functional form of inulin is produced by removing all fractions with chain lengths lower than 10.

Teichuronic acid is isolated from the cell walls of Micrococcus luteus. The structure has been elucidated as [ManNAcUAp-(β-1,6)-Glcp-(α -1,4)]n.

Methyl cellulose is a synthetic polymer of cellulose. It is prepared by treating the natural polymer with a methylating agent, such as dimethyl sulfate. Methylation is carried out in the presence of an acid catalyst to produce mainly methyl ethers and methyl esters. The degree of substitution may be controlled by the amount of catalyst. Methyl cellulose is used as a thickener, emulsifier, or stabilizer in many food products, including ice cream and toothpaste.

Fluorescein isothiocyanate carboxymethyl dextran (FITC-CM Dextran) has been reported to provide a valuable carrier for nanoparticles of iron oxide.  These products provide a potent tool for contrast enhancement in magnetic resonance imaging.

Oat β-glucans are water-soluble β-glucans derived from the endosperm of oat kernels, which contain β-1,3 and β-1,4 linkages. They are known for cholesterol lowering and hypoglycemic properties, as well as their use in various cosmetic applications. Recent research has shown their potential application in immunomodulation and wound healing.

Dextran sulphate is a dextran derivative whose ulcer (colitis) -causing properties were first reported in hamsters and extrapolated a few years later to mice and rats. The exact mechanisms through which dextran sulphate induces intestinal inflammation are unclear but may be the result of direct damage of the monolayer of epithelial cells in the colon, leading to the crossing of intestinal contents (for e.g. commensal bacteria and their products) into underlying tissue and therefore induction of inflammation.  The dextran sulphate sodium induced ulceration model in laboratory animals has some advantages when compared to other animal models of colitisdue to its simplicity and similarities to human inflammatory bowel disease.

Kappa-Carrageenan is a gelling sulphated galactan extracted from red seaweed (typically Mastocarpus stellata and Chondrus crispus). The structure of all carrageenans consists of a strictly alternating masked repeating unit of 1,3-linked α-D-galactose and 1,4-linked β-D-galactose. The α-linked galactose occurs as α-3-6-anhydro unit and the β-linked sugar occurs as the 4-sulphate. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Guar gum is obtained from the seed of the legume Cyamopsis tetragonolobus, an annual plant that grows mainly in semi-arid regions of India. The structure of the polysaccharide consists of a main chain of (1,4)-linked β-D-mannopyranosyl units with single α-D-galactopyranosyl units linked (1,6) on average to every second main chain unit. Guar has a high viscosity in aqueous solution, shows marked pseudoplastic behaviour and forms synergistic gels in the presence of other gums such as carrageenan and xanthan gum.

Pustulan is a β-1,6-glucan isolated from Lasallia pustulata MW (20 kDa). It is recognized by the membrane bound Dectin-1, a C-type lectin-like pattern recognition receptor. Detection of β-glucans by Dectin-1 receptor leads to the CARD9-dependent activation of NF-κB and MAP kinases.  Studies have shown that pustulan can stimulate innate immune responses, inducing heat shock protein expression, eliciting phagocytosis, and production of pro-inflammatory cytokines. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Chondroitin sulfate A sodium from bovine trachea is a natural substance that has been found to have potential anticancer properties. It has been shown to inhibit the growth of cancer cells in Chinese hamster ovary cells and human urine tumor cell lines. Chondroitin sulfate A sodium from bovine trachea works by inhibiting kinases, which are proteins that play a key role in cell growth and division. This inhibition leads to apoptosis, or programmed cell death, in cancer cells. Additionally, chondroitin sulfate A sodium from bovine trachea has been found to enhance the anticancer activity of artesunate analogs, making it a promising candidate for combination therapy in cancer treatment.

The sodium salt of hyaluronic acid is a glycosaminoglycan found in many organs, where it functions as a joint lubricant and shock absorber. It is obtained principally from synovial fluid, vitreous humor of the eye, umbilical tissue and cocks comb. The chemical structure of hyaluronic is a disaccharide repeat of β-(1,3) glucuronic acid and β-(1,4) N-acetyl glucosamine.

Gycosaminoglycan in many organs; joint lubricant and shock absorber.  Made by a bacterial, Streptococcus fermentation.

Ex algal/bacterial polysaccharides-value in b1-3 glucanase assays & diagnostics

Chitosan is the deacetylated form of chitin.  The polysaccharide is deacetylated in order to render it soluble, which is then possible at pH values of less than 7 (normally in dilute acid).  This then allows the material to be used in a number of industrial applications as a binder and film former.MW typically 10-100kDa.

Lichenin, the poly β-D-Glucan of Cetraria islandica (Iceland moss), is found by enzymic degradation to differ in fine structure from the poly β-D-glucans of cereal grains. Thus, the basic structure of lichenin is a tetrameric unit in which two adjacent 1,4 linkages alternate with an isolated 1,3 linkage; occasionally four consecutive monomers are linked by 1,4 bonds. The immunomodulatory activity of isolichenan was tested in in vitro phagocytosis and anti-complementary assays, and proved to be active in both cases. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

A fucan sulphate found in brown marine algae (Phaeophyta-typically Fucus vesiculotus, Ascophyllum nodosum (illustrated), Alaria and Cladosiphon) and has been shown to have anticoagulant activity. The main constituents are α-1,4 and α-1,2 linked L-fucose sulphates although galactose also occurs and there are many variations of the basic structure found in different species of Phaeophyta.Molecular weight cut off at 300kDa.The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Carboxymethyl curdlan is widely used in the preparation of nanoparticles for biomedical applications. Following the synthesis of superparamagnetic iron oxide nanoparticles (SPIN) capped with carboxymethyl curdlan for use in cellular and in vivo imaging applications, the stability and dispersibility of SPIN in water were greatly improved with the introduction of the carboxymethyl curdlan moiety. Recently, a green and simple route was proposed to synthesize Ag nanoparticles using carboxymethylcurdlan under UV irradiation.

Starch is an energy storing polysaccharide produced by higher plants and some algae. Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol. It consists of two types of polysaccharide: the linear and helical amylose (α-1,4-linked glucose) and the branched amylopectin (α-1,4 and α-1,6-linked glucose). Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight.

Compression wood is a type of reaction wood formed on the underside of softwood stems when they are tilted from the vertical and on the underside of branches, which unlike normal wood contains significant amounts of β-(1,4)-galactan.

Gycosaminoglycan in many organs; joint lubricant and shock absorber

Applications 2-Amino-2-deoxygalacturonic acid was a component of the lipopolysaccharide from P. aeruginosa NCTC 8505 and probably occurs in the region of polysaccharide responsible for O-antigenic specificity. References Wilkinson, S.G., et al.: Biochem. J., 149, 783 (1975),

Dextran sulphate is a dextran derivative whose ulcer (colitis) -causing properties were first reported in hamsters and extrapolated a few years later to mice and rats. The exact mechanisms through which dextran sulphate induces intestinal inflammation are unclear but may be the result of direct damage of the monolayer of epithelial cells in the colon, leading to the crossing of intestinal contents (for e.g. commensal bacteria and their products) into underlying tissue and therefore induction of inflammation.  The dextran sulphate sodium induced ulceration model in laboratory animals has some advantages, when compared to other animal models of colitis, due to its simplicity and similarities to human inflammatory bowel disease.

Pectins are derived from citrus fruits such as lemons and limes. Amidated pectin is a modified form of pectin in which some of the galacturonic acid residues are converted with ammonia to amides. These pectins are more tolerant to varying calcium concentrations that occur in use and behave like low-ester pectins, need less of and are more tolerant to excess calcium. In addition, these gels are thermoreversible.

An alginate-like polysaccharide produced by the fermentation of Azotobacter vinelandii or Pseudomonas mendocina. The chemical structure consists of blocks of (1,4) linked-β-D-polymannuronic acid (poly M), (1,4) linked-α-L-polyguluronic acid (poly G) and alternating blocks of the two uronic acids (poly MG). Unlike the alginate from seaweed, this polysaccharide is partially acetylated.

Rhamnogalacturonan is a natural polysaccharide that is a major component of plant cell walls. It can be synthesized in the laboratory and modified with different functional groups to alter its properties. Rhamnogalacturonan has been shown to have anti-inflammatory, antioxidant, and immunomodulatory activities. It also has the ability to inhibit bacterial growth and stimulate phagocytosis by macrophages. This product has a high purity, is custom synthesized, and can be modified with different functional groups.

Polyguluronic acid is produced from alginates by partial hydrolysis and chromatography of brown algae such as Laminaria digitata, Ascophyllum nodosum and Fucus spp. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.MW is less then 8000Da.

Gellan is a microbial polysaccharide produced by Pseudomonas elodea and generates gels with similar properties to agar. Gellan gum is a linear tetrasaccharide of (1,4)-β-L-rhamnopyranosyl, (1,3)-α-D-glucopyranosyl, (1,4)-β-D-glucuronopyranosyl, (1,4)-β-D-glucopyranosyl- with O(2) L-glyceryl and O(6) acetyl substituents on the 3-linked glucose. Both substituents are located on the same glucose residue, and on average, there is one glycerate per repeat and one acetate per every two repeats. In low acyl gellan gum, the acyl groups are removed completely. The high acyl form produces soft, elastic, non-brittle gels, whereas the low acyl form produces firm, non-elastic, brittle gels.

Chitosan is the deacetylated form of chitin.  The polysaccharide is deacetylated in order to render it soluble, which is then possible at pH values of less than 7 (normally in dilute acid).  This then allows the material to be used in a number of industrial applications as a binder and film former.

Chitosan is the deacetylated form of chitin. The polysaccharide is deacetylated in order to render it soluble, which is then possible at pH values of less than 7 (normally in dilute acid). This then allows the material to be used in a number of industrial applications as a binder and film former.

Pectin is a highly complex polysaccharide matrix that is found in the primary walls of dicotyledenous and monocotyledenous plants and gymnosperms, including soy plants. A key fragment of this complex is rhamnogalacturonan I, containing a backbone of the repeating disaccharide  [-4)-α-D-GalpA-(1,2)-α-L-Rhap-(1,]. Several applications for RG1 have been described including drug targeting to the colon via the oral administration route for local treatment of e.g. inflammatory bowel disease and colonic cancer. This has several advantages such as needle-free administration and low infection risk and in the gastro-intestinal tract RG-I is only degraded by the action of the colonic microflora.  High purity rhamnogalacturonan I is also used in research, biochemical enzyme assays and in vitro diagnostic analysis.

Fluorescein isothiocyanate carboxymethyl dextran (FITC-CM Dextran) has been reported to provide a valuable carrier for nanoparticles of iron oxide.  These products provide a potent tool for contrast enhancement in magnetic resonance imaging.