Structural characterization and antioxidant properties of polysaccharides from two Schisandra fruits

Different polysaccharides (NPS1-1 and BPS1-1) were obtained from Schisandra sphenanthera and Schisandra chinensis fruits by hot-water extraction, DEAE-52 ion-exchange column chromatography and Sephadex G-150 gel filtration chromatography. Structure characteristic and antioxidant properties of NPS1-1 and BPS1-1 were comparatively investigated by gas chromatography, Fourier transform infrared spectroscopy, scanning electron microscopy, multi-angle laser light scattering analysis, atomic force microscope, circular dichroism spectroscopy, scavenging DPPH free radicals assay, ferric-reducing power assay and lipid peroxidation inhibition assay, respectively. Results showed that physicochemical and antioxidant properties of NPS1-1 and BPS1-1 were different from each other. Molecular weights of NPS1-1 and BPS1-1 were 2.22 x 10(6) and 2.66 x 10(6), respectively. NPS1-1 and BPS1-1 could be a kind of rhamnogalacturonan, and the sugar chain contained pyran configurations and beta-glycosidic linkages. Significant differences in the surface features and particle distribution of NPS1-1 and BPS1-1 were detected. NPS1-1 showed higher antioxidant abilities on ferric-reducing power and lipid peroxidation inhibition activity. The results would be helpful for the further use of the two fruits.