猴头菇β-葡聚糖的结构表征及其稀溶液性质

Structural Characterization and Dilute Solution Properties of Hericium erinaceus β-Glucan

以猴头菇子实体为原料,通过水提醇沉法提取得到猴头菇β-葡聚糖(Hericium erinaceus β-glucan,HEBG)。采用高效液相色谱、气相色谱、傅里叶变换红外光谱、高碘酸氧化、Smith降解、甲基化分析和核磁共振分析对HEBG的一级结构进行表征;通过特性黏度测定实验和刚果红实验对HEBG溶液性质进行探究,并通过扫描电子显微镜和原子力显微镜对HEBG进行显微结构的观察。结果表明:HEBG是由β-D-葡萄糖组成的均一性多糖;高碘酸氧化、Smith降解、甲基化分析和核磁共振分析结果表明HEBG主链由1,3-β-D-葡萄糖残基组成,支链是由1,6-β-D-葡萄糖残基组成,且1,3-β-D-葡萄糖与1,6-β-D-葡萄糖的物质的量比为1∶1。特性黏度和刚果红实验表明,HEBG稀溶液中不仅存在无规线团结构,还存在三股螺旋结构;扫描电子显微镜和原子力显微镜更加清晰地观察到多糖的无规线团结构、分子链的分支状结构,分子链直径为(0.55±0.11)nm,宽度为1.9 nm。该实验为深入研究HEBG的生物活性以及构效关系提供一定参考依据。

Hericium erinaceus β-glucan (HEBG) was obtained from the fruiting body of H. erinaceus by water extraction and alcohol precipitation. The primary structure of HEBG was characterized by high performance liquid chromatography (HPLC), gas chromatography (GC), infrared spectroscopy (IR), periodate oxidation, Smith degradation, methylation analysis and nuclear magnetic resonance (NMR) analysis. The solution properties of HEBG were investigated by viscosity measurement and Congo red tests, and its microstructure was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that HEBG was a homogeneous polysaccharide composed of β-D-glucose (Glu). Periodate oxidation, Smith degradation, methylation analysis and NMR analysis indicated that the HEBG backbone consisted of 1,3-β-D-Glu residues and the branches were composed of 1,6-β-D-Glu residues with a molar ratio of 1,3-β-D-Glu to 1,6-β-D-Glu residues of 1:1. The intrinsic viscosity and Congo red tests showed that the dilute HEBG solution had both a random coil and triple helix structure, and the random coil structure of the polysaccharide and the branching structure of its molecular chain were more clearly observed by SEM and AFM. The molecular chain diameter was (0.55 ± 0.11) nm and the width was 1.9 nm. This study provides the rationale for an in-depth study of the biological activity and structure-activity relationship of H. erinaceus β-glucan.