Structural characterization and antioxidant activity of polysaccharide from Hohenbuehelia serotina

•NTHSP-A1 was isolated and purified by the antioxidant tracking from Hohenbuehelia serotina.•The structure of NTHSP-A1 was identified by HPSEC, FT-IR, GC-MS, NMR and AFM.•NTHSP-A1 consists mainly of arabinose, mannose, glucose and galactose.

Previous research found that the polysaccharides isolated from Hohenbuehelia serotina possessed various biological activities, such as antioxidant, immunomodulation and radioprotective effects. However, the structural information of H. serotina polysaccharides has not yet been reported. Therefore, based on the investigation of the antioxidative tracking, a novel polysaccharide named as NTHSP-A1 was isolated from H. serotina by ultrasonic-assistance extraction and anion-exchange and gel permeation chromatography approaches. Structural characterization revealed that NTHSP-A1 had an average molecular weight of 8.09 × 103 Da and composed of arabinose, mannose, glucose and galactose in a molar ratio of 4:16:28:11. The polysaccharide was semi-crystalline substance with multi-branching structure. The backbone of NTHSP-A1 was shown to contain →3,6)-α-d-Glcp-(1→, with branches substituted at C-3 of →2)-α-l-Arap-(1→, C-3 of α-d-Manp-(1→, and C-6 of →6)-β-d-Galp-(1→, respectively. This study provides a theoretical basis for the further research on the relationship between biological activity and structure of NTHSP-A1.

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