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We studied the effect of two pectic polysaccharides PS-B1-AG and PS-B2-RG that were contained in total polysaccharides extracted from Betula pendula leaves on NO production by mouse macrophages and the contribution of signaling molecules to macrophage activation by the test substances. Unlike the total sample, pectins produced a NO-stimulating effect on macrophages. The effect of PS-B2-RG (10 μg/ml) did not differ from the effect of LPS, while PS-B1-AG produced this effect only in a concentration of 20 μg/ml, which was probably due to differences in the chemical structure of the test substances. The studied pectin polysaccharides activated transcription factor NF-κB, kinases p38 and PI3, and cAMP as a negative regulator. These results indicate that Betula pendula polysaccharides are promising substances for creation of immunomodulating drugs.

A pectic polysaccharide was isolated from the rhizomes of Acorus calamus L. The main component of its carbohydrate chain was represented by residues of D-galacturonic acid (>85%). In addition, this polysaccharide contained residues of galactose, arabinose, xylose and rhamnose (<10%). Structural analysis of pectic polysaccharide from A.calamus L. with NMR spectroscopy indicated that it contains the regions of a linear 1,4-alpha-D-galactopyranosyluronan, which represents a major component of the macromolecule. A considerable amount of galacturonic acid residues was not methoxylated. We demonstrate here that the pectic polysaccharide from A. calamus L. in low concentrations was able to stimulate in vitro IL-12 and nitric oxide production by murine macrophages. It also induced TNF-alpha secretion by human peripheral blood mononuclear cells, reduced arginase activity but did not affect IL-10 secretion by murine macrophages or human peripheral blood mononuclear cells. The IL-12 and NO-stimulating effects on murine macrophages were similar to that of LPS. In addition, the polysaccharide promoted in vivo Th1 immune response in mice which were immunized with sheep red blood cells (DTH and quantity of plaque-forming cells) and down regulated serum level of IgG1 and IgE during Th2-depend immune response induced by ovalbumin. The PS increased Th1-induced edema and suppressed Th2-induced paw swelling in adoptive systems. Our results suggest that the pectic polysaccharide from A. calamus L. represents a promising immunomodulating agent that stimulates M1-polarized macrophages and promotes Th1-oriented adaptive immune response. We propose that this polysaccharide could be potentially applied for treatment of infectious, oncological diseases or for immunoglobulin-E-mediated disorders., ((c) 2010 Elsevier B.V. All rights reserved.)