Intestinal Immune System Modulating Polysaccharides from Rhizomes of Atractylodes lancea

Abstract

Hot water extract (ALR-0) of rhizomes of Atractylodes lancea DC. was fractionated into MeOH-soluble fraction (ALR-1), supernatant fraction of EtOH precipitation (ALR-3+4), and crude polysaccharide fraction (ALR-5). Among these fractions, only ALR-5 showed potent stimulating activity for proliferation of bone marrow cells mediated by Peyer's patch cells. ALR-5 gave three potently active carbohydrate-rich fractions (ALR-5lla, 5llb, and 5llc) by anion-exchange chromatography on DEAE-Sepharose CL-6B, and three active polysaccharides (ALR-5lla-1-1, ALR-5llb-2-2, and ALR-5llc-3-1) were further purified from the respective fractions. The order of activity was revealed to be ALR-5llb-2-2 ≥ ALR-5lla-1-1 > ALR-5llc-3-1. ALR-5lla-1-1, 5llb-2-2, and 5llc-3-1 each was eluted as a single peak on HPLC and their molecular weights were estimated to be 74,000, 3,100, 16,000, respectively. ALR-5lla-1-1 consisted mainly of Ara and Gal (molar ratio; 0.6:1.0) in addition to a trace amount of uronic acid whereas ALR-5llb-2-2 and ALR-5llc-3-1 mainly comprised Ara, Gal, GlcA, and GalA (molar ratio; 0.2 :1.0:0.2 :0.8, and 0.5:1.0:0.7:1.5, respectively). Methylation analysis indicated that ALR-5lla-1-1 consisted mainly of terminal Araƒ, 4- or 5-linked Ara, 3,4- or 3,5-branched Ara, and 3-linked, 4-linked, and 3,6-branched Gal. ALR-5llb-2-2 and ALR-5llc-3-1 were composed mainly of terminal Araƒ, 4- or 5-linked Ara, 4-linked Gal, 4-linked GalA, and terminal GlcA. In addition, ALR-5llb-2-2 mainly comprised 4-linked Xyl whereas ALR-5llc-3-1 consisted mainly of 2,4-branched Rha. Single radial gel diffusion indicated that ALR-5lla-1-1 showed a strong reactivity with β-glucosyl-Yariv antigen, whereas ALR-5llb-2-2 and ALR-5llc-3-1 did not show the reactivity with the antigen. Treatments of ALR-5lla with NalO₄, NaCIO₂ and pronase did not reduce the stimulating activity for Peyer's patch cells, however combination of exo-α-L-arabinofuranosidase and exo-β-D-(1→3)-galactanase digestions of ALR-5lla-1-1 significantly decreased its activity.

Key words

Atractylodes lancea DC. - Compositae - arabino-3,6-galactan - pectic polysaccharide - intestinal immune system modulating activity - Peyer's patch cell