Structural characterization and antioxidant activity of an acetylated Cyclocarya paliurus polysaccharide (Ac-CPP0.1)

The aim of this study was to investigate the primary structure of an acetylated Cyclocarya paliurus polysaccharide (Ac-CPP0.1) and its protective effect on H2O2-treated dendritic cells. The backbone of Ac-CPP0.1 was →3)-β-D-Galp-(1→, with some branches α-L-Araf-(1→ residues at O-6 and O-5, β-D-Galp-(1→ and 3,5,6)-β-D-Galf-(1 residues at O-4 and acetyl groups were substituted at the O-2 and O-6 positions of 3)-β-D-Galp-(1 residues. The CPP0.1 and Ac-CPP0.1 significantly increased the levels of superoxide dismutase, glutathione peroxidase and catalase on H2O2-treated dendritic cells. Meanwhile, both CPP0.1 and Ac-CPP0.1 up-regulated the expression of Nrf2 (NF-E2-related factor 2) and down-regulated the Keap1 (Kelch-like ECH-associated protein-1), but Ac-CPP0.1 had a better effect on antioxidant capacity. These results indicated that potential application of Ac-CPP0.1 as an antioxidant agent. •A polysaccharide fraction from Cyclocarya paliurus was acetylated (Ac-CPP0.1).•Primary structure of Ac-CPP0.1 was characterized.•Acetyl groups were substituted at the O-2 and O-6 positions of galactose residues•Ac-CPP0.1 enhanced antioxidant activity via Nrf2-Keap1 pathways.•Ac-CPP0.1 exhibited stronger antioxidant activity on H2O2-treated dendritic cells