Preparation, structural analysis and antioxidant activities of phosphorylated (1 → 3)-β-d-glucan

The aim of this study was to investigate the effect of phosphorylation on the antioxidant activity of (1 → 3)-β-d-glucan from yeast cell wall. Alkali-insoluble (1 → 3)-β-d-glucan was extracted from yeast cell wall by an acid-base method. It was found that the purity of the sample was greatly improved after the precipitation was treated with alkali at 90 ℃ and then by acetic acid, which was about 96.5%. Phosphorylated (1 → 3)-β-d-glucan was prepared. Infrared (IR) spectra and nuclear magnetic resonance spectra (NMR) confirmed the successful introduction of phosphate into glucan. The substitution degree of phosphate was 0.18. The phosphorylated (1 → 3)-β-d-glucan could significantly increase SOD and CAT contents in serum, liver and brain of mice, and reduce MDA level in serum, liver and brain to a certain extent in vivo. This lays a solid foundation for the research and development of phosphorylated (1 → 3)-β-d-glucan antioxidant.