Chemical Features and Purification of Immunostimulating Polysaccharides from the Fruit Bodies of Agaricus blazei

Water-soluble polysaccharides from the fruiting bodies of Agaricus blazei Murill were extracted with 0.9% sodium chloride and hot water, successively. The purified polysaccharides showed a potent immunostimulating activity. Eight major polysaccharides, which were named from AG-l to AG-8, were fractionated and purified by ethanol precipitation, ion exchange chromatography on DEAE-cellulose and gel filtration on Toyopearl HW 65F. These polysaccharides were identified to be homogeneous by analysis of HPLC. Three major active polysaccharides (AG-2, -3, and -6) showed relatively strong immunostimulating activity. AG-2 and -3 were composed of glucose, galactose and mannose in the molar ratios of 74.0:15.3:10.7 and 63.6:17.6:12.7, respectively. AG-6 was composed of glucose and ribose in the molar ratios of 81.4:12.6.