Polysaccharides

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).

Chromogenic substrate for the measurement of endo-inulinase

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.