Purification, Preliminary Characterization and Antioxidant Activity of Polysaccharides from Green Husks of Walnut (Juglans regia L.) Grown in Changbai Mountain

In this study, polysaccharides named as JPs were ultrasonically extracted from walnut green husks. After sequential treatments of ethanol precipitation, deproteinization and dialysis, JPs were fractionated by DEAE-Sepharose and Sephadex G-100 column chromatography into two homogenous fractions (JPs-1-1 and JPs-2-1). The molecular masses of JPs-1-1 and JPs-2-1 were measured to be 5.45 × 104 and 5.22 × 104 u by high performance gel filtration chromatography, respectively. Monosaccharide analysis by precolumn derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) coupled to high performance liquid chromatography (HPLC) indicated that both polysaccharides were composed of rhamnose, glucuronic acid, galactose, glucose, galacturonic acid, xylose and arabinose, but in different molecular ratios. JPs and its fractions possessed a good antioxidant activity in terms of ferric-reducing antioxidant power and scavenging activities against hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals in a dose-dependent manner within a certain concentration range. © 2019, China Food Publishing Company. All right reserved.