Structural Characterization of a Water-Soluble Polysaccharide from the Fruiting Bodies of Agaricus bisporus

An edible fungal polysaccharide termed as ABP was obtained by extraction with hot water, and followed successive chromatographic purification using DEAE-Sepharose Fast Flow column and Sephacryl S-300 High-Resolution column. A symmetrical peak was obtained on high-performance size-exclusion chromatography with an average molecular weight of 5.17 × 10(4) Da, which was named ABP, and its main components were d-glucose and d-mannose. Based on the study of methylation analysis, along with FT-IR, GC, GC-MS, 1D (1)H and (13)C NMR and 2D NMR (H-HCOSY, TOCSY, HMQC, and NOESY), its chemical structure was featured with a repeating unit (1→6) linking β-d-Glcp as the main backbone with (1→4)-linked α-d-Manp units. The structure of the mainly repeating units of ABP was established as: [Formula: see text]