Extraction, characterization and antioxidant activity of mycelial polysaccharides from Paecilomyces hepiali HN1

• The hot water extraction of PHMPS was optimized by a Box–Behnken design.
• The maximum extraction yield of PHMPS was 11.08 ± 0.22%.
• The preliminary characterization of PHMPS was performed.
• Crude PHMPS exhibited potent antioxidant activity in vivo.

Optimization of extraction, characterization and antioxidant activity of mycelial polysaccharides from Paecilomyces hepiali HN1 (PHMPs) were investigated. As results, the optimal parameters for extraction of PHMPs were obtained by a Box–Behnken design as follows: extraction temperature 92 °C, extracting time 190 min and ratio of water to material 43 mL/g. The analysis of monosaccharide composition by high performance liquid chromatography (HPLC) revealed that PHMPs was composed of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose and arabinose in molar ratio of 46.07:0.59:2.25:1.29:1.42:18.82:26.17:1.13:2.26, respectively. Furthermore, it was demonstrated that PHMPs had a significant protective effect against oxidative stress induced by d-galactose in mice, as evident by higher activities of superoxide dismutase, catalase, glutathione peroxidase and level of total antioxidant capacity, as well as lower levels of malondialdehyde in serums and livers compared to the d-galactose-treated group. These results suggested that PHMPs could be explored as promising natural antioxidant.