Structural characterization and antioxidant activity of a novel high-molecular-weight polysaccharide from Ziziphus Jujuba cv. Muzao

A novel high-molecular-weight polysaccharide (PZMP2-1) was extracted and purified from Ziziphus Jujuba cv. Muzao. Chemical and instrumental studies revealed that PZMP2-1 had an average molecular weight (Mw) of 141 kDa and consisted of rhamnose, arabinose, galactose, and galacturonic acid with the molar ratio of 0.84:5.88:0.31:0.12. Structural features of PZMP2-1 were investigated via FT-IR, XRD, SEM, AFM, NMR spectroscopy and GC–MS analysis. Methylation and NMR analysis indicated that PZMP2-1 primarily contained of → 5)-a-L-Araf-(1 → , and → 3,5)-a-L-Araf-(1 → residue in the backbone. The branched chain was connected to the main chain through the O-3 atom of arabinose, and terminated with Araf. The results of bioactivity experiments showed that PZMP2-1 had antioxidant in vitro, especially on scavenging DPPH and hydroxyl radicals. Overall, these results suggested that jujube polysaccharides could be developed as a potent antioxidant agent for use in functional food and dietary supplements.