Structure and in vitro antioxidant and immunomodulatory activity of a glucan from the leaves of Cyclocarya paliurus

In this study, a novel polysaccharide (CPP-80) was prepared from the leaves of Cyclocarya paliurus and its detailed structure, antioxidant and immunomodulatory effects were explored in vitro. The results showed that CPP-80 was a glucan and its main chain consisted of -> 4)-alpha-D-Glcp-(1 -> 4)-beta-D-Glcp-(1 ->, while the end groups alpha-D-Glcp-(1 -> 3)-alpha-D-Glcp-(1 -> and alpha-D-Glcp-(1 -> 6)-alpha-D-Glcp-(1 -> were linked to the main chain by the O-3 of the -> 3,4)-alpha-D-Glcp-(1 -> and the O-6 of the -> 4,6)-alpha-D-Glcp-(1 -> bonds, respectively. In vitro, CPP-80 had a certain reducing ability and antioxidant activities with the scavenging ratios of 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2 '-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals and hydroxyl radicals from about 50 % to more than 80 % at a concentration of 4 mg/mL. Additionally, CPP-80 could immunomodulate RAW264.7 macrophages by boosting phagocytosis and encouraging the release of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL -6). Thus, CPP-80 could be used as a promising antioxidant and immunomodulator for food and pharmaceutical applications.