Physicochemical properties and antioxidant activities of polysaccharide from floral mushroom cultivated in Huangshan Mountain

•A polysaccharide fraction (FMPS) was extracted from Huangshan floral mushroom for the first time.•The primary structure and advanced structure of FMPS was studied.•Investigated the antioxidant activity of FMPS by different manners. In this paper, a polysaccharide fraction (FMPS) was purified from the floral mushroom cultivated in Huangshan Mountain for the first time. Physicochemical properties and antioxidant activities of FMPS were investigated. FMPS had an average molecular weight of 7.2×105Da and was composed of glucose. On the basis of FT-IR, NMR and methylation analysis, the repeating unit of FMPS was established as (1→3)-linked β-d-glucopyranosyl backbone with 1-linked β-d-glucopyranosyl branches substituted at O-6 position of (1→3)-linked β-d-glucopyranosyl residues. The advanced structure studies indicated that FMPS was a triple-helical polysaccharide. The main hydrodynamic radius (Rh) of FMPS was 23.4nm and it could form a stable system with water in 1.2×10−2g/mL solutions. In addition, FMPS exhibited high DPPH radical scavenging activities (79.46% at 5mg/mL) and hydroxyl radical scavenging activities (74.18% at 5mg/mL), as well as Fe2+chelating activities and ABTS radical scavenging activities to some extent.