Polysaccharides

Porphyran is an agar-like polysaccharide with a linear backbone consisting of 3 linked β-D-galactosyl units alternating with either 4-linked α-L-galactosyl 6-sulphate or 3-6-anhydro-α-L-galactosyl units.The composition includes 6-O-sulphated L-galactose, 6-O-methylated D-galactose, L-galactose, 3,6-anhydro-L-galactose, 6-O-methyl D-galactose and ester sulphate. Some of the ester is present as 1,4-linked L-galactose 6-sulphate. The precise composition of porphyran shows seasonal and environmental variations. Porphyran is not used commercially, but the seaweed, Porphyra umbilicalis, is edible and is consumed in Wales (Laver). It is also made into a delicacy called Laverbread. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Chondroitin sulfate A sodium salt is a glycosaminoglycan that is derived from chondroitin. It is a complex carbohydrate with a high molecular weight and an average MW of 10,000 to 50,000 Da. The synthesis of the monosaccharide units in chondroitin sulfate A sodium salt occurs by Methylation, Click modification, Polysaccharide, or Fluorination. Chondroitin sulfate A sodium salt can be custom synthesized according to customer specifications and can be ordered as a CAS No. 39455-18-0 with high purity.

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.

Laminaran is a polysaccharide that co-occurs with fucoidan and alginate in brown seaweeds such as Laminaria digitata, Laminaria cloustoni, Eisenia bicyclis and Thallus laminariae. It is a β-1,3-linked glucan which it is claimed stimulates the immune system in mammals and fish. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Laminaran is a polysaccharide that co-occurs with fucoidan and alginate in brown seaweeds such as Laminaria digitata, Laminaria cloustoni, Eisenia bicyclis and Thallus laminariae. It is a β-1,3-linked glucan which it is claimed stimulates the immune system in mammals and fish. The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Isolichenan is a cold-water soluble (1,3)-(1,4)-α-D-glucan isolated from lichen Cetraria islandica to have MW of about 6-8 kDa. Lichens produce isolichenan-type polysaccharides with considerable variation in linkage ratios as well as MW, even within the same species. Occasionally these α-glucans can be branched at O2, O3 or O6. The immunomodulating 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’.

Sodium polymannuronate 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’.

Chondroitin sulphate is the most abundant glycosaminoglycan in mammalian tissues and occurs both in skeletal and soft connective tissue. The disaccharide repeat unit consists of N-acetyl galactosamine sulphate linked β1,4 to glucuronic acid.

In their simplest forms, xylans are linear homopolymers of β-1,4-xylose residues. In nature they are partially substituted by acetyl, 4-O-methyl-D-glucuronosyl and α-1,3 L-arabinofuranosyl residues, forming complex heterogenous and polydispersed glycans. An example of this is in the L-arabino (methyl-D-glucurono) xylan from corn cob.