Intestinal Peyer's patch-immunomodulating glucomannans from rhizomes of Anemarrhena asphodeloides Bunge.

During screening for intestinal Peyer's patch-immunomodulating polysaccharides from plant resources including medicinal herbs, a potent modulating activity was observed in a crude polysaccharide fraction (AS-1) from the rhizome of Anemarrhena asphodeloides Bunge. Oral administration of AS-1 (100 mg/kg/day) to aged BALB/c mice enhanced productions of IL-10, IFN-γ and IL-6 from Peyer's patch immunocompetent cells, and its oral administration to ovalbumin (OVA)-fed B10.A mice led to significant suppression on induction of OVA-specific IgE in systemic immune system. Further fractionation of the polysaccharides in the crude polysaccharide fraction, AS-1, yielded 4 polysaccharide fractions that were potently active, and contained glucomannans. Treatment of these polysaccharide fractions with endo-ß-D-(1→4)-mannanase significantly decreased their activities. Mannanase digestion of the active glucomannan gave both long and short hexosyl-oligosaccharides, whereas konjac glucomannan, which was inactive, released short oligosaccharides. Structural analysis indicates that the long oligosaccharides from the active glucomannan contain mannanase-resistant complex structure comprising ß-D-Man and ß-D-Glc.

Different contributions of side-chains in beta-D-(1-->3,6)-galactans on intestinal Peyer's patch-immunomodulation by polysaccharides from Astragalus mongholics Bunge.

Thirteen polysaccharides isolated from an extract of the aerial portions of Astragalus mongholics Bunge demonstrated immunomodulating activity against Peyer's patch immunocompetent cells. Nine of the active polysaccharide fractions were composed of either arabinogalactans, pectic arabinogalactans or pectins. The activities of the arabinogalactans and pectic arabinogalactans were associated with beta-D-(1-->3)-galactan moieties branched with beta-D-(1-->6)-galactooligosaccharide side-chains having degrees of polymerization of 8 or less. Degradation of the beta-D-(1-->3)-galactan or beta-D-(1-->6)-galactosyl side-chains in the arabinogalactans significantly decreased immunomodulating activity. Rhamnogalacturonan I (RG-I) with beta-D-(1-->3,6)-galactosyl side-chains having terminal beta-D-GlcA showed activity in the pectin-enriched fractions. Interestingly, the terminal GlcA was not required for activity of the arabinogalactan-enriched fractions, suggesting at least two different immunomodulating structures.

[Elucidation of structures and functions through Peyer's patches of responsible carbohydrate chains in intestinal immune system modulating polysaccharides from Japanese medicinal herbs].

Carbohydrate chains in glycoconjugates play important roles in various life phenomena, and there are numerous types of recognition system for carbohydrate chains due to carbohydrate-lectin interactions/carbohydrate-carbohydrate interactions in all higher life forms. It has been proposed that macromolecular polysaccharides isolated from plants, marine organisms, or fungi cross-interact with known and unknown recognition systems in mammals to express their pharmacological activities. Therefore the elucidation of carbohydrate structures related to the activities and functions of these polysaccharide molecules will lead us to utilize the related information in the development of novel carbohydrate-based drugs and functional foods for human health care. Peyer's patches present in the upper intestinal tract play important roles as inductive sites for both protective IgA production and immune tolerance induction in mucosal and systemic immune systems. Dysfunction of the immunocompetent cells of Peyer's patches is thought to induce allergic/autoimmune diseases and down-regulation of the protective system against infectious agents on mucosal sites. We have isolated several Peyer's patch cell-modulating polysaccharides from medicinal herbs used in traditional Japanese herbal remedies, and they have been assumed to comprise the responsible carbohydrate chains with oligosaccharide sizes for expression of modulating activity. Accumulation of knowledge on the structures and functions of these responsible carbohydrate chains in polysaccharide molecules is believed to be important for the development of methodology for logically factitious regulation of functions of immunocompetent cells in Peyer's patches. This review deals with recent results of our study on the structural clarification of responsible carbohydrate chains in modulating polysaccharides against functions of immunocompetent cells in Peyer's patches.