【作者】 毛旭宏； 张黎明； 杨立群；

【Author】 Xuhong Mao;Li-Ming Zhang;Liqun Yang;School of Materials Science and Engineering, School of Chemistry, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education,Guangdong Provincial Key Laboratory for High Performance Polymer-based Composites, Sun Yat-sen University;

【机构】 材料科学与工程学院化学学院聚合物复合材料及功能材料教育部重点实验室广东省高性能树脂基复合材料重点实验室中山大学；

【摘要】 茶多糖是茶叶中的一种成分,研究发现,它是一种具有降血糖活性的酸性杂多糖[1],但被小肠吸收的效率很差。为了提高茶多糖被小肠吸收的效率并提高其生物利用度,本工作从粗老绿茶中分离提取出一种酸性杂多糖(TPSA)[2],并以糖原作为原料、以维生素B12(VB12)为小肠靶向因子,合成出偶联了VB12和二乙烯三胺基(DETA)的含VB12基团的阳离子糖原衍生物(GD-VB12)。通过FTIR法和1H NMR法分析其结构。制备出阳离子糖原衍生物和TPSA的复合物(GD-VB12/TPSA)纳米粒,通过Zeta电位仪测定其Zeta电位为正值,且电位值随着GD-VB12的量增加而增加,说明TPSA被包裹在复合物的内部。通过扫描电镜观察了其微观形态,复合物大致呈现球形,且粒径在100nm左右。利用荧光光谱法深入研究了TPSA与GD的复合机理,发现TPSA与GD之间属于荧光增强的复合体系,利用不同质量比下的荧光强度变化值可以计算复合体系的焓变(△H)和熵变(△S),计算结果显示,△H=-24.96 kJ/mol,△S=34.06 J/K·mol,根据文献工作[3],这些结果表明TPSA与GD主要是通过静电相互作用力形成稳定的纳米粒。更多还原

【Abstract】 Tea polysaccharide, an importantly active component of tea, has been identified as an acidic heteropolysaccharide with hypoglycemic activity [1]. However, it is hardly absorbed by the small intestinal mucosa. In order to improve the absorption of tea polysaccharide, an acidic branched tea polysaccharide(TPSA) was isolated from low-grade green tea [2], and a cationic glycogen derivative bearing diethylenetriamine(DETA) and vitamin B12 residues, named as GD-VB12, was synthesized in this work.The structure was characterized by FTIR and 1 H NMR analyses. The GD-VB12/TPSA nano-complex was then prepared in the distilled water, and the zeta potential of the complex was positive and increased with the increasing amounts of GD-VB12,resulting that TPSA was encapsulated in the complex. Besides, its microscopic morphology was observed as spherical particles with sizes ranging about 100 nm.Furthermore, the interaction mechanism of TPSA with GD were investigated using fluorescence spectroscopy, and the variations in the fluorescence intensities have been used to calculate the enthalpy change(△H) and the entropy change(△S) of complex,the calculation results showed that △H =-24.96 kJ/mol,△S=34.06 J/K·mol. The result indicated that the electrostatic interaction might play a major role in the binding of TPSA to GD according to the literature [3].更多还原