Mannan oligosaccharide

Glucomannan is a water-soluble polysaccharide that is considered a dietary fiber. It is a hemicellulose component in the cell walls of some plant species. Glucomannan is a food additive used as an emulsifier and thickener. Products containing glucomannan, under a variety of brand names, are marketed as nutritional supplements with false claims they can help weight loss. The U.S. Food and Drug Administration (FDA) has not approved any product containing glucomannan for the treatment of any medical condition and its use may be harmful. They are also used to supplement animal feed for farmed animals.

Glucomannan is mainly a straight-chain polymer, with a small amount of branching. The component sugars are β-(1→4)-linked D-mannose and D-glucose in a ratio of 1.6:1. The degree of branching is about 8% through β-(1→6)-glucosyl linkages.

Glucomannan with α-(1→6)-linked galactose units in side branches is called galactoglucomannan.

In the yeast cell wall, mannan oligosaccharides are present in complex molecules that are linked to the protein moiety. There are two main locations of mannan oligosaccharides in the surface area of Saccharomyces cerevisiae cell wall.

They can be attached to the cell wall proteins as part of –O and –N glycosyl groups and also constitute elements of large α-D-mannanose polysaccharides (α-D-Mannans), which are built of α-(1,2)- and α-(1,3)- D-mannose branches (from 1 to 5 rings long), which are attached to long α-(1,6)-D-mannose chains.

This specific combination of various functionalities involves mannan oligosacharides-protein conjugates and highly hydrophilic and structurally variable 'brush-like' mannan oligosaccharides structures that can fit to various receptors of animal digestive tracts, and to the receptors on the surface of bacterial membranes, impacts these molecules bioactivity. Mannan oligosacharides-protein conjugates are involved in interactions with the animal's immune system and as result enhance immune system activity. They also play a role in animal antioxidant and antimutagenic defense.

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