Polysaccharides

Gum Jhingan is a modified carbohydrate with a fluorinated saccharide. It is an oligosaccharide that has been synthesized from the sugar galactose. Gum Jhingan is a high-purity, custom-synthesized product that has been methylated and glycosylated. The modification process of this carbohydrate includes fluorination and click chemistry.

Xanthan gum is a polysaccharide produced by the Gram negative bacteria Xanthomonas campestris. It has unique rheological and gel forming properties and finds many applications particularly in the food and oil industries. 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 structure of xanthan is based on a cellulosic backbone of β-(1,4)-linked glucose units which have a trisaccharide side chain of mannose-glucuronic acid-mannose linked to every second glucose unit in the main chain. Some terminal mannose units are pyruvylated and some of the inner mannose units are acetylated.

Applications 3-O-Methyl-d3 Quercetin is the labeled analogue of 3-O-Methyl Quercetin (M326545), a metabolite of the flavanoid Quercetin (Q509500) with inhibitory activity on lipopolysaccharide-induced activation of macrophage U937 cells. Not a dangerous good if item is equal to or less than 1g/ml and there is less than 100g/ml in the package References Okoko, T. et al.: Food Chem. Toxicol., 47, 809 (2009); Duenas, M. et al.: Eur. Food Res. Technol., 232, 103 (2011); Marzouk, M. et al.: Phytochem., 52, 943 (1999)

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.

Ulvans are structural polysaccharides present in the cell walls of green algae such as Ulva armoricana, Ulva rotondata, Ulva rigida, Ulva lacterca and Ulva pertusa. They are highly sulphated and contain rhamnose 3-sulphate, xylose, xylose 2-sulphate, glucuronic acid and iduronic acid residues. Ulvan has several potentially valuable functionalities such as gel formation for agricultural and food applications and possible anticoagulant, antioxidant, antihyperlipidemic and antitumoral activities for pharmaceutical applications. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

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.

Anterograde and retrograde tracer in neurons; biologically inert

A fucan sulphate found in brown marine algae (Phaeophyta-typically Fucus serratus, Ascophyllum nodosum, Laminaria digitata (illustrated) and Macrocystis pyrifyra) 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. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

An apiose-rich pectic polysaccharide zosterin is found in the sea grass Zostera marina and is typical of similar structures occurring in higher plants. The structure consists of an α-1,4-D-galactopyranosyluronan backbone substituted by 1,2-linked apiofuranose oligosaccharides and single apiose residues. The average molecular mass of the polysaccharide has been shown to be about 4100 Da with a low polydispersity.

Gycosaminoglycan in many organs; joint lubricant and shock absorber

Curdlan is a microbial polysaccharide produced by a mutant strain of Alcaligenes faecalis var. myxogenes which was first shown to produce succinoglucan prior to mutation. Curdlan is a β-1,3 glucan forming clear solutions at about 55 °C which then gels (“low-set”) when cooled. Suspensions of curdlan at higher temperatures form firm resilient gels (“high set”) that melt at 140 - 160 °C. The image was kindly provided by Dr. Chris Lawson.

Colominic acid (polysialic acid) is a linear small polysaccharide containing α-2,8-linked sialic acid (neurominic acid) with (n = 8 to >100) residues. Polysialic acid is an unusual post translational modification polysaccharide that is widely expressed in nature in bacterial capsules, fish, sea urchin eggs, embryonic tissues, amphibians, animal and human brains, and in a various cancers.  The major carrier of polysialic acids in mammals is the neural cell adhesion molecule (a glycoprotein that belongs to the immunoglobulin superfamily).Average molecular weight for this product is :50000-60000

Food additive, applied in pharmaceuticals and beauty products.

Heparin is a glycosaminoglycan which occurs in many mammalian tissues and has important anticoagulant and thrombolytic properties. The chemical structure is composed mainly of two disaccharide repeating units A and B. A is L-iduronic acid 2-suplhate linked α-(1,4) to 2-deoxy-2-sulfamido-D-galactose 6-sulphate while B is D-glucuronic acid β-(1,4) linked to 2-deoxy-2-sulfamido-D-glucose 6-sulphate.

Fluorescein dextran (FD) is widely used as both an anterograde and retrograde tracer in neurons and for numerous other applications. It is biologically rather inert having α-1,6-linked glucose residues resistant to cleavage by most endogenous cellular glycosidases. It has low immunogenicity and makes an ideal long-term tracer for live cells. FD also serves as a valuable marker for cell loading of macromolecules by micro-injection, vesicular fusion, and electroporation, as well as for the uptake and internal processing of exogenous materials by phagocytotic and endocytic pathways.

Pullulan is a glucan elaborated by the fungus Aureobasidium pullulans. The chemical structure is essentially repeating units of maltotriose joined by α-1,6 linkages. Pullulan dissolves readily in water to form stable, viscous solutions that do not gel. The polysaccharide can be moulded, made into fibres and forms clear soluble films. Applications are in foods as a low calorie ingredient and the polysaccharide forms water soluble films that have been used as seed coatings and to coat fruit. Pullulan can also be used in industrial applications as a binder, film former and in pharmaceutical applications.  Average MW is typically 100-200kDa.  Viscosity is ca 120 mm2/s. The image was kindly provided by Dr. Chris Lawson.

A fucan sulphate found in brown marine algae (Phaeophyta-typically Fucus vesiculotus, Durvillea (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. The fucose content of this fucan is approximately 27.9% and it also contains galactose (approx. 6.2%), uronic acid (approx. 22.4%) and sulfate (approx. 21.4%). 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, Ecklonia (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. The fucose content of this fucan is approx. 19.0% and it also contains galactose (approx. 12.0%), uronic acid (approx. 25.5%) and sulfate (approx. 19.1%). The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Gycosaminoglycan in many organs; joint lubricant and shock absorber

The disaccharide repeating unit of chondroitin sulphate consists of N-acetyl galactosamine sulphate linked β1,4 to glucuronic acid. Each monosaccharide may be left unsulphated, sulphated once, or sulphated twice. The most common pattern is that the hydroxyl groups of the 4 and 6 positions of the N-acetyl-galactosamine are sulphated, with some chains having the position 2 of the glucuronic acid sulphated.

Hypromellose phthalate (hydroxypropyl methylcellulose phthalate, or HPMCP) is a phthalic acid ester of hydroxypropyl methylcellulose.  Hypromellose phthalate was introduced in 1971 as a cellulose derivative for enteric coatings, used to protect drugs from degradation by gastric acid or to prevent them from causing side effects in the stomach.  HPMCP is also used in sustained-release preparations, in binders and as microcapsule bases.

Poria cocos is an edible medicinal fungus known as “Fuling” in Chinese that has been used as a Chinese traditional medicine for more than two thousand years. Polysaccharide material is the most abundant organic substance in the fungus, accounting for about 85% of the total and is a mixture of polysaccharides with the major component being Pachyman, a β-glucan with a 1,3 backbone and 1,6 side chains. It is reported that Pachyman has a wide range of biological activities including antitumour, immunomodulatory, anti-inflammatory and antioxidative properties. Pachyman is a beta-glucan with a 1,3 backbone and 1,6 side chains of fungal origin (Poria cocos). The image was kindly provided by Dr. Chris Lawson.

Hydroxypropyl methylcellulose (HPMC or hypromellose) is a semisynthetic, inert and viscoelastic polymer that is used as eye drops and as semi-synthetic substitute for tear-films. When applied, a hypromellose solution acts to swell and absorb water, by increasing the thickness of the tear-film, resulting in decreased eye irritation.  In addition to its use in ophthalmic liquids, hypromellose has been used as an excipient in oral tablet and capsule formulations, where, depending on the grade, it functions as controlled-release agent. It is also used as a binder and as a component of tablet coatings.  Hypromellose in aqueous solution, unlike methylcellulose, exhibits thermal gelation properties. HPMC is approved as a food additive, emulsifier, thickening and suspending agent, and as an alternative to animal gelatin (Codex Alimentarius code (E number) is E464).