Polysaccharides from Baizhu were separated by preparative hydrophilic interaction liquid chromatography on an XAmide column and its components were characterised as inulin-type polysaccharides with structures of α-D-glucopyranosyl-[-(1 → 2) -β-D-fructofuranosyl-](n -1)-(1 → 2) -β-D-fructofuranoside (n = 3-20) by a combinatory application of electrospray-ionisation mass spectrometry, nuclear magnetic resonance and IR, as well as the chemical analysis of monosaccharide composition. In addition, the contents of nystose and 1F-fructofranosylnystose in the crude and purified Baizhu polysaccharides were determined to be 5.81%, 4.92% and 0.70%, 0.84% (w/w), respectively. In addition, MTT assay indicated that the Baizhu polysaccharides could effectively promote spleen lymphocyte transformation for the enhancement of organism immunity. It is for the first time that inulin-type polysaccharides were discovered in Baizhu and its immuno-enhancing activity was reported, which is a vigorous evidence to explain the efficacy of Baizhu.
Keywords: Atractylodes macrocephala Koidz; XAmide column; inulin-type oligosaccharides; spleen lymphocyte transformation.