High Molecular Weight Glucan of the Culinary Medicinal Mushroom Agaricus bisporus is an α-Glucan that Forms Complexes with Low Molecular Weight Galactan

Molecules

Fhernanda R. Smiderle¹  Guilherme L. Sassaki¹  Jeroen van Arkel¹  Marcello Iacomini¹  Harry J. Wichers¹ 

[1] ¹Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands ²Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Paraná, Centro Politécnico, CP 19046, Curitiba-PR, Brazil ³Wageningen University and Research Centre, Bornse Weilanden 9, 6708 WG Wageningen, Netherlands

关键词: Agaricus bisporus;    basidiomycetes;    a-glucan;    medicinal mushrooms;    polysaccharides;    NMR;   

DOI  :  10.3390/molecules15085818

来源: mdpi

【 摘 要 】

An a-glucan was isolated from the culinary medicinal mushroom A. bisporus by hot water extraction, ethanol precipitation and DEAE-cellulose chromatography. The resulting material showed a single HMW peak excluded from a Sephadex G50 column that could completely be degraded by α-amylase treatment. After heating in 1% SDS a small additional peak of low MW eluted from the G50 column. The monosaccharide composition of the main peak was evaluated by HPLC, and was found to consist of a majority of glucose (97.6%), and a minor proportion of galactose (2.4%). Methylation analysis and degradation by a-amylase indicated the presence of an a-glucan with a main chain consisting of (1®4)-linked units, substituted at O-6 by α-D-glucopyranose single-units in the relation 1:8. Mono- (¹³C-, ¹H-NMR) and bidimensional [¹H (obs.),¹³C-HSQC] spectroscopy analysis confirmed the a-configuration of the Glcp residues by low frequency resonances of C-1 at d 100.6, 100.2, and 98.8 ppm and H-1 high field ones at d 5.06, 5.11, and 4.74 ppm. The DEPT-¹³C-NMR allowed assigning the non-substituted and O-substituted –CH₂ signals at d 60.3/60.8 and 66.2 ppm, respectively. Other assignments were attributed to C-2, C-3, C-4, C-5 and C-6 of the non-reducing ends at d 71.8; 72.8; 70.0; 71.3 and 60.3/60.8 ppm, respectively. The minor proportion of galactose that was demonstrated was probably derived from a complex between the a-glucan and a low molecular weight galactan.

【 授权许可】

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