Structure of an entangled heteropolysaccharide from Pholidota chinensis Lindl and its antioxidant and anti-cancer properties.

A major polysaccharide PCP-I was isolated and purified from Pholidota chinensis Lindl. The physicochemical and structural properties of PCP-I were studied using high-performance size-exclusion chromatography (HPSEC), gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR), periodate oxidation-smith degradation, methylation-GC-MS analysis, nuclear magnetic resonance (NMR) spectroscopy and transmission electron microscopy (TEM) analysis. PCP-I was homogeneous with molecular weight (Mw) of 249kDa and composed of xylose and fucose at a molar ratio of 2.45:1. The repeating structural units of PCP-I were →3)-α-D-Xylp-(1→ and →4)-α-L-Fucp-(1→, the terminal fractions were T-D-GalAp, and TEM further revealed that PCP-I was the entangled microstructure which was composed of four non-branched single chains. Compared with Vitamin C (Vc) and 5 fluorine urine (5-Fu), PCP-I showed scavenging effects of superoxide (EC50 =1.09mg/mL) and hydroxyl (EC50 =0.11mg/mL) radicals equivalent to Vc, and PCP-I (IC50 =69.54μg/mL) also exhibited good anti-proliferation capability for human colon cancer cell line caco-2.