超声提取的麦冬多糖POJ-U1b的结构分析及AFM观测

Structural Analysis and Observation of Ophiopogon japonicus Polysaccharide POJ-U1b

本文利用超声提取麦冬多糖,经DEAE-52纤维素柱层析进行分离纯化,利用Sephadex G-150凝胶柱层析对得到的多糖组分POJ-U1b进行纯度鉴定,结果显示POJ-U1b为单一组分。利用气相色谱法、红外光谱法及核磁共振对POJ-U1b的结构进行了研究,利用原子力显微镜对不同浓度的POJ-U1b表面形貌进行了观测。结果显示,麦冬多糖POJ-U1b是由葡萄糖组成的葡聚糖,具有糖类物质的特征吸收峰,其糖环构型既有吡喃型又有呋喃型,糖链主要由→6)-α-D-Glcp(1→连接方式构成。AFM观测结果表明POJ-U1b具有高度分支的化学结构,糖链间通过糖单元间不同的链接方式衍生出许多环状和分支结构。随着多糖浓度的增大,POJ-U1b呈现出链状及片状粘连结构,这种现象可能与糖链间的范德瓦尔斯相互作用及糖链间氢键缔合有关。

Ophiopogon japonicus polysaccharide was ultrasonically extracted. It was separated and purified by DEAE-52 cellulose column to afford the polysaccharide POJ-Ulb. The purity of POJ-Ulb was determined by Sephadex G-150 gel column. The result showed that POJ-Ulb was homogeneous. The structure of POJ-U1 b was determined by gas chromatog- raphy,infrared spectrometry and nuclear magnetic resonance, and the surface morphology of POJ-U1 b at different con- centrations was observed by atomic force microscopy （AFM）. The results showed that POJ-U1 b was glucan composed by glucose. The infrared spectrum suggested that there were characteristic absorption bands of polysaccharide in POJ-Ulb, and its monosaccharide residues existed in the forms of pyran and furan rings. POJ-Ulb was mainly composed of →6）-α-D-Glcp（1→linkage. AFM revealed that POJ-Ulb had a multi-branched chemical structure in linkages of adjacent monosaccharides, ringed and branched structure was derived from link of polysaccharide chains. With the increasing of concentration ,POJ-U1 b presented chain and flakiness conglutinate structure, which was related to van der Waals interac- tion and hydrogen bond of pulysaccharide chains.