Purification, structural elucidation, and anti-inflammatory effect of a water-soluble 1,6-branched 1,3-α-d-galactan from cultured mycelia of Poria cocos

Poria cocos has recently been commercially used to formulate nutraceuticals and functional foods in Taiwan. In this study, P. cocos, was cultured and polysaccharides were extracted, followed by fractionation with size-exclusion column chromatography to give a water-soluble 1,6-branched 1,3-α-d-galactan (PC-II). The predominant monosaccharide was galactose after complete hydrolysis of the polysaccharide. The chemical structure was characterised by a monosugar analysis, along with 1H, 13C, and 2D nuclear magnetic resonance spectroscopy, including NOESY and HMBC experiments for linkage and sequence analysis. This polysaccharide is composed of a high-galactose-type undecasaccharide repeating unit with the following structure: showed no toxicity to endothelial cells (ECs) and dose-dependently suppressed production of the interferon (IFN)-γ-induced inflammation marker, IP-10. However, PC-II showed no effect on cancer cell cytotoxicity or antiangiogenic activity. These results suggest that PC-II may play roles in regulating the anti-inflammatory process.