Antioxidant and antibacterial activities of polysaccharides isolated and purified from Diaphragma juglandis fructus

•The crude DJPs was purified by DEAE-Cellulose and Sephadex G-100 chromatography.•A new polysaccharide named DJP-2 was purified for the first time.•The structural character of DJP-2 was investigated.•DJP-2 exhibited significant antioxidant activities and antibacterial activities. A water-soluble polysaccharide fraction (DJP-2) isolated from Diaphragma juglandis was successfully purified by ion-exchange chromatography (DEAE-cellulose) and gel-permeation chromatography (Sephadex G-100). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of DJP-2 were 4.95 and 3.99kDa, respectively. Monosaccharide component analysis indicated that DJP-2 comprised arabinose, galactose, glucose, xylose, and mannose in a molar ratio of 0.27:0.55:1:0.14:0.08. The evaluation of the antioxidant and antibacterial activities of polysaccharides from Diaphragma juglandis fructus indicated that they could be explored as promising natural antioxidant and bacteriostatic agents in the food and pharmaceutical industries.