Preparation, characterization of polysaccharides fractions from Inonotus obliquus and their effects on alpha-amylase, alpha-glucosidase activity and H2O2 induced oxidative damage in hepatic L02 cells

In the present study, three homogeneous protein bounded acidic polysaccharides fractions (IOPS-1, IOPS-2 and IOPS-5) were isolated from I. obliquus using DEAE-52 cellulose chromatography. The relationship between their physicochemical properties and bioactivities was comparatively investigated. Results showed that IOPS-1, IOPS-2 and IOPS-5 were composed of rhamnose, arabinose, xylose, mannose, glucose and galactose with the molecular weight distribution range from 75.94 kDa to 114.30 kDa. Congo red assay and CD spectra revealed that these three polysaccharides had ordered triple-helical conformations. Among the three polysaccharides, IOPS-2 exhibited the highest enzymes inhibitory activity and protective effects against the H2O2 induced oxidative damages in hepatic L02 cells, which would be related to its specific molecular weight (97.12 kDa), protein and uronic acid contents, rough appearance and triple-helical conformation. These results might facilitate the development of polysaccharides from I. oblqiuus as alternative antioxidants and provide significant insights into the relationship of structure-bioactivity of natural polysaccharides.