Polysaccharides

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.