Polisacáridos

In water, hydroxypropyl cellulose forms liquid crystals with many mesophases depending on concentration. These mesophases include isotropic, anisotropic, nematic and cholesteric, the latter resulting in many colors such as violet, green and red. Pharmaceutical applications include treatments for medical conditions such as dry eye syndrome (keratoconjunctivitis sicca), recurrent corneal erosions, decreased corneal sensitivity, exposure and neuroparalytic keratitis. It is also used as a binder in tablets. Hydroxypropylcellulose is also used as a thickener, a binder and emulsion stabiliser in foods with E number E463.  HPC is used as a support matrix for DNA separations by capillary and microchip electrophoresis.

Dextran is α-(1,6)-linked α-D-glucan produced by fermentation of Leuconostoc mesenteroides via the action of the enzyme dextransucrase on sucrose. The main use for native dextran is as a blood plasma extender in blood transfusions. A complex of iron with dextran, known as iron dextran, is used as a source of iron to baby piglets which are often anaemic at birth.

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 cut-off 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.

Cellulose with a particle size of 20μm is an industrial biomass material that has various applications. It is commonly used in the production of paper, textiles, and biofuels. Cellulose is a complex carbohydrate that provides structural support to plant cell walls. It can also be used as an excipient in pharmaceutical formulations, such as in the production of tablets. In addition to its industrial uses, cellulose has been studied for its antioxidant activity. It has been found to inhibit lipid peroxidation, which is a process that can lead to oxidative damage in cells. This antioxidant property makes cellulose a potential ingredient in skincare products or dietary supplements aimed at promoting overall health and well-being. Cellulose can be extracted from various sources, including wood pulp and agricultural waste. It is typically processed using solvents like chloroform or methanol to remove impurities and obtain a pure form of cellulose. With its versatility and wide range of applications, cellulose with a particle size

Iota-Carageenan is a gelling sulphated galactan extracted from red seaweed (typically Euchuma cottonii and Euchuma spinosum). 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 a 3,6-anhydro-2-sulphate 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’.

Octyl-agarose is a type of agarose gel that has been modified to contain 20% ethanol solution. It is used in the purification of oligosaccharides and monosaccharides, as well as in the synthesis of complex carbohydrate. Octyl-agarose can be custom synthesized or modified with glycosylation, methylation, sugar, or carbohydrate modifications.

Scleroglucan is produced by the fermentation of the fungus Sclerotium rolfsii. It is a glucan with a main chain of 1,3-linked β-D-glucopyranosyl units with every third unit having a single β-D-glucopyranosyl unit linked 1,6. Scleroglucan powders disperse in water and give very viscous shear thinning solutions. Applications are in the oil industry in enhanced oil recovery, in agriculture in sprays and in the food and pharmaceutical industries. The image was kindly provided by Dr. Chris Lawson.

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.

Gum tragacanth is an exudate gum from species of Astragalus trees mainly grown in Iran and Turkey. Tragacanth finds applications as an effective emulsifying and thickening agent in the food and pharmaceutical industries. The gum is a slightly acidic salt consisting of two fractions namely the water soluble tragacanthin and the fraction bassorin which swells in water to form a gel. Water soluble tragacanthin is reported as a branched arabiogalactan which is soluble in 70% ethanol. The acidic bassorin has a chain of (1,4)-linked a-D-galacturonic acid units some of which are substituted at O-3 with β-D-xylopyranosyl units and some of these being terminated with galactose or fucose.

Sodium salt of a polysaccharide obtained from the brown seaweeds (e.g. Laminaria hyperborea, Fucus vesiculosus, Ascophyllum nodosum). 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). Alginates form strong gels with divalent metal cations and the egg box model has been used to describe this form of gelation. The main use for alginate is in textile printing as a thickener in the printing of cottons with reactive dyes. In the food industry it is used as a thickener and gelling agent.  Recently, it has been shown that ternary mixtures of Konjac glucomannan, Xanthan gum and Sodium alginate can form a non-covalently linked complex which exhibits enhanced rheological properties of value in, for example, functional foods. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.