Abstract:

Among eight common medicinal and edible Chinese herbs, namely Rhizoma Atractylodis Macrocephalae, Fructus Lycii Chinensis, Radix Pseudostellariae, Fructus Schisandrae Chinensis, Radix Codonopsitis, Radix Rehmanniae, Pericarpium Citri Reticulatae and Glossy Ganoderma), the water extract from Rhizoma Atractylodis Macrocephalae had the most obvious promoting effect on the in vitro growth of Bifidobacterium infantis. A neutral polysaccharide fraction was obtained from Rhizoma Atractylodis Macrocephalae after water extraction (1:20 raw material/water ratio), absolute ethanol precipitation (1:3 concentrated crude extract/absolute ethanol), dialysis (through a membrane with a molecular weight cut-off of 3500 D), Sevag deproteinization and DEAE anion exchange column chromatographic separation. The polysaccharide fraction had a promoting effect on the growth of Bifidobacterium and Lactobacillus, especially on B. infantis, B. animalis, B. adolescentis and Lactobacillus plantarum in a concentration-dependent fashion. The infrared spectral analysis showed that the fraction had characteristic absorption peaks of polysaccharides, and its weight-average molecular weight (Mw) was measured to be 5527 g/mol using GPC coupled with a multiangle laser light scattering photometer (GPC-MALLS) and its molecular weight distribution (Mw/Mn) was 1.726. The analysis using acidic hydrolysis followed by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) revealed that the polysaccharide was a hetero polysaccharide and its monosaccharide composition consisted of rabinose, galactose, glucose and mannose in a molar ratio of 13.8:11.8:70.2:4.1.

Key words: Rhizoma Atractylodis Macrocephala polysaccharide, growth promoting effect, molecular weight, monosaccharide composition, probiotics