Polysaccharides immunostimulatory

Polysaccharides are generally indigestible to humans, so their effects are not manifested in the bloodstream. However, their physical movement through the colon appears to trigger certain physiological reactions in humans, possibly due to an immune reaction via the Peyer s patches. Immunostimulatory polysaccharides are large, insoluble, extensively branched molecules often occurring in triple helix formation (Turner 1998). 

From a theoretical point of view, the immunostimulatory polysaccharides can only be expected in phytopreparations which have been prepared with aqueous solvents. By 50% (VA ) ethanol the immunostimulatory active polysaccharides are precipitated, as can be seen from their isolation protocol [120]. Therefore, such preparations should be void of these polysaccharides. However, aqueous preparations and also expressed saps at least have the potential to contain them, and it would be desirable to establish corresponding standardization methods. 

LAB are Gram-positive bacteria with cell wall components such as peptidoglycan, polysaccharide, and teichoic acid, all of which have been shown to have immunostimulatory properties. In addition to cell wall components, immunostimulatory effects were observed with antigens originated from the cytoplasms of some strains of LAB. 

Echinacea is one of the best-selling herbal products in the United States (Brevoort, 1998) and is promoted as an immunostimulatory agent (Bauer, 1999a, 2000). The alkamides, caffeic acid derivatives (e.g., cichoric acid), glycoproteins, and polysaccharides are believed to be responsible for Echinacea s observed immunostimulatory activity. Bauer (1997) reported that the variation in alkamide concentrations of Echinacea products was due to a number of factors such as growing season, which part of the plant was utilized in the preparation of the commercial product,... 

In this class of compounds, the number of possible polyclonal ligands that may react with surface structures of immunocompetent cells appears, at first glance, to be unlimited. However, the relatively small number of compounds that have reached the drug market until now demonstrates that the ability of a compound to effectively stimulate the immune system is dependent on several factors, such as secondary and tertiary structure, conformation, molecular weight, solubility, etc. Proteins, polysaccharides and glycopeptides are among the most preferred natural products with immunostimulatory activity. 

Systematic fractionation and subsequent pharmacological testing of the aqueous extracts of the aerial parts of . purpurea led to the isolation of two polysaccharides (PS I and PS II) with immunostimulatory properties [118, 119]. Structural analysis... 

From pharmacological investigations it is obvious that not a single, but several constituents like the alkamides, cichoric acid, glycoproteins and polysaccharides, contribute to the immunostimulatory activity of Echinacea extracts (for summary see Tab. 1) [152,153]. Therefore the application of extracts is still reasonable and hence the native extract is regarded as the active principle for regulatory purposes by the health authorities [154]. However, standardization of these extracts is a must for a rational therapeutic application of phytopreparations [155, 156], and reproducible quality needs also to be documented from a regulatory point of view [157, 158]. 

Some mushroom polysaccharides or complexes of polysaccharide and proteins can stimulate nonspecific immunity and boost the host s defenses against tumors. Medicinal mushrooms have their history as immunostimulatory and immunomodulating therapeutics in the management of tumor, viral, and bacterial diseases but little is known on dietary intakes of commonly consumed mushrooms in association with... 

Bauer and Wagner concluded that the immunostimulatory activity of alcoholic and aqueous extracts depend on the combined action of several constituents. In lipophilic fractions, alkylamides and the polar caffeic acid derivative cichoric acid contribute to activity of alcoholic extracts. Polysaccharides are implicated in the expressed juice of E. purpurea and aqueous extracts, as well as orally administered powdered whole drug. ... 

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