Characterization and antioxidant properties of polysaccharides from flowers of Sophora japonica L. (Huaihua)

Sophora japonica L. flower polysaccharides (SJFP) were extracted with hot water, the crude polysaccharides were de-proteinized by Sevag method and fractionized by DEAE-52 column chromatogram. Five fragments were obtained, namely SJFP-A, SJFP-B1, SJFP-B2, SJFP-B3 and SJFP-B4. SJFP-A and SJFP-B3 were further purified by Superdex G-200 filtration column chromatography. The resulted two fractions SJFP-AA and SJFP-BB were characterized by Fourier transform infrared spectrophotometer (FTIR) and high pressure gel filtration chromatography (HPGFC). Monosaccharide composition was determined by high performance capillary electrophoresis (HPCE). SJFP-AA was composed of rhamnose, xylose, arabinose, and mannose with the molar ratio of 1: 6.14: 4.03: 1.48, while SJFP-BB was made up of rhamnose, arabinose, and mannose with the molar ratio of 6.26: 1: 1.87. Additionally, the crude SJFP exhibited good antioxidant activity in a dose-dependent manner. At the concentration of 4 mg/ml, the hydroxyl radical scavenging effect of crude SJFP was 90.32%, comparable to 92.63% for the positive control ascorbic acid (P > 0.05).   Key words: Flowers of Sophora japonica L., polysaccharides, purification, antioxidant activity.