壳聚糖衍生物的合成及其性质研究

发布时间：2018-05-08 15:07

本文选题：壳聚糖 + 化学改性　；参考：《江南大学》2017年硕士论文

【摘要】：壳聚糖(CS)是自然界唯一存在的碱性多糖,因具有来源广泛、生物相容性好、无毒无害等优点而受到广泛关注,同时壳聚糖还具有抗氧化、抑菌等生物活性,但由于其分子内和分子间的氢键作用及结构特点,导致壳聚糖的溶解性很差(酸性溶液除外),抑菌、抗氧化活性也相对较低,严重影响了壳聚糖在食品、医药、生物等领域的应用。因此本课题通过化学改性,引入其他功能性基团来改善壳聚糖的性质。本课题对壳聚糖进行了三种化学改性,得到了三种新的壳聚糖衍生物,通过傅里叶变换红外光谱、核磁共振图谱、X-射线衍射、元素分析等手段进行结构解析。研究了壳聚糖衍生物的热稳定性、水溶性、抗氧化性、胆酸结合力和抑菌活性,主要结果如下:1.首先在TEMPO催化体系下将壳聚糖的C6位羟基氧化成羧基,再用3-氯丙酸在C2氨基上发生取代反应,分离纯化后得到的衍生物即为N,O-羧基壳聚糖(NTCS),经傅里叶变换红外光谱、1H核磁共振图谱、X-射线衍射确定产物的结构。物性实验结果表明N,O-羧基壳聚糖的热稳定性低于壳聚糖,在水中的溶解度为15.005 g/100 m L H2O,是原料壳聚糖溶解度(0.705 g/100 m L H2O)的近20倍,且粘度比壳聚糖低,总羧基含量为2.833 mmol/g。抗氧化实验结果表明,N,O-羧基壳聚糖的DPPH自由基清除力、羟基自由基清除力和还原力均高于壳聚糖,体外胆酸结合力为17.209 mg/g,比壳聚糖的胆酸结合力(3.804 mg/g)高3.5倍。2.将壳聚糖C6羟基改性成氨基来改善壳聚糖的抑菌性。经C2氨基邻苯二甲酰化,C6羟基对甲苯磺酰化、叠氮化、还原,以及C2氨基脱保护后,得到6-氨基壳聚糖(NCS)。由红外光谱、X-射线衍射和元素分析解析结构。改性后衍生物的热稳定性降低,不同摩尔比(壳聚糖:4-甲苯磺酰氯=1:5、1:10、1:15)反应得到的6-氨基壳聚糖的取代度分别为0.190、0.335、0.487。抗氧化实验表明6-氨基壳聚糖具有更高的DPPH自由基清除力、羟基自由基清除力和还原力,1.2 mg/m L时的值分别为92.19%、62.81%、0.611。对大肠杆菌和金黄色葡萄球菌的抑菌实验表明,氨基的引入增强了壳聚糖的抑菌性。3.以水溶性壳寡糖为原料,在其羟基上引入香草酸。甲烷磺酸既可以保护氨基,又是反应的溶剂。首先香草酸的羧基酰氯化,然后与壳寡糖的羟基发生酯化反应,氨基脱保护后,得到香草酸-O-壳寡糖(VA-O-COS),由傅里叶变换红外光谱、13C核磁共振图谱、X-射线衍射表征结构。研究发现香草酸-O-壳寡糖的结构变得更加规整有序,热稳定性增强。香草酸和壳寡糖在不同摩尔比(1:2、1:3、1:5)下反应得到的衍生物的取代度分别为0.750、0.912、1.064。衍生物的DPPH自由基清除力、羟基自由基清除力和还原力均有所改善,1.2 mg/m L时的值分别为85.46%、58.52%、0.733。抑菌试验表明香草酸-O-壳寡糖对大肠杆菌和金黄色葡萄球菌的抑菌性均高于壳寡糖。结果表明,改性后得到的三种衍生物,其抗氧化性和抑菌活性(或胆酸结合力)均有所增强,为开发高效安全的壳聚糖类抗氧化剂、防腐抑菌剂等提供了新的思路。
[Abstract]:Chitosan (CS) is the only alkaline polysaccharide existing in nature. Because of its extensive sources, good biocompatibility, non-toxic and harmless advantages, chitosan has been widely concerned. At the same time, chitosan has the biological activity of antioxidation and bacteriostasis. However, the solubility of chitosan is very poor due to its intramolecular and intermolecular hydrogen bonding and structural characteristics. With the exception of the solution), the antibacterial activity and the antioxidant activity are relatively low, which seriously affect the application of chitosan in the fields of food, medicine, biology and so on. Therefore, this subject has been modified by chemical modification to improve the properties of chitosan. In this subject, three kinds of Chitosan were chemically modified and three new chitosan derivatives were obtained. The thermal stability, water solubility, antioxidation, cholic acid binding and antibacterial activity of chitosan derivatives were studied by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, X- ray diffraction, and elemental analysis. The main results were as follows: 1. first, the C6 hydroxyl group of chitosan was oxidized to carboxyl group under the TEMPO catalytic system, and then the carboxyl group was oxidized to the carboxyl group. The substitution reaction of 3- chloro propionic acid on C2 amino group, the derivatives obtained after separation and purification are N, O- carboxyl chitosan (NTCS). The structure of the products is determined by Fourier transform infrared spectroscopy, 1H NMR spectrum and X- ray diffraction. The results of physical properties experiment show that the thermal stability of N, O- carboxyl chitosan is lower than that of chitosan, and the solubility in water is 1. 5.005 g/100 m L H2O is nearly 20 times the solubility of chitosan (0.705 g/100 m L H2O), and the viscosity is lower than chitosan and the total carboxyl content is 2.833 mmol/g. antioxidant experiment results. The scavenging force of DPPH radicals, the hydroxyl radical scavenging force and the return force of the N and O- carboxyl chitosan are higher than that of the chitosan, and the binding force of cholic acid in vitro is 17.209. The Bacteriostasis of chitosan was improved by modifying the chitosan C6 hydroxyl group by 3.5 times.2. (3.804 mg/g) to improve the Bacteriostasis of chitosan. After C2 amino phthalic two methylation, C6 hydroxyl toluene sulfonylation, azide, reduction, and C2 amino deprotection, 6- amino chitosan (NCS) was obtained. Infrared, X- ray diffraction and elemental analytical solutions were obtained. The thermal stability of the modified derivatives decreased, and the degree of substitution of different Molby (chitosan: 4- toluylsulfonyl chloride =1:5,1:10,1:15) was 0.190,0.335,0.487. antioxidant experiment, respectively, which showed that 6- amino chitosan had higher DPPH radical scavenging force, hydroxyl radical scavenging force and reducing force, 1.2 mg/ The values of M L were 92.19%, 62.81%, and 0.611. for Escherichia coli and Staphylococcus aureus. The antibacterial activity of Escherichia coli and Staphylococcus aureus showed that the introduction of amino group enhanced the antimicrobial activity of chitosan with water soluble chitosan oligosaccharides as raw material and the introduction of vanillic acid on its hydroxyl groups. Methane sulfonic acid could protect both amino and reaction solvents. First, the carboxyl chloride of oxalic acid. The structure of vanillin -O- shell oligosaccharide (VA-O-COS) was characterized by Fu Liye transform infrared spectroscopy, 13C NMR atlas and X- ray diffraction. The structure of -O- chitosan oligosaccharides was found to be more orderly and orderly, and the thermal stability was enhanced. Vanillin and chitosan oligosaccharides were found in the study. The degree of substitution of the derivatives under the different molar ratio (1:2,1:3,1:5) is the DPPH radical scavenging force of the 0.750,0.912,1.064. derivative, the hydroxyl radical scavenging force and the reducing force are improved, the values of the 1.2 mg/m L are 85.46%, 58.52%, respectively, and the bacteriostasis test of vanilla acid -O- shell oligosaccharides to Escherichia coli and Staphylococcus aureus The Bacteriostasis of Staphylococcus was higher than that of chitosan oligosaccharides. The results showed that the three derivatives obtained after modification had enhanced antioxidant and bacteriostasis activity (or cholic acid binding force), which provided new ideas for the development of efficient and safe chitosan antioxidant and antiseptic and bacteriostat.

【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O636.1

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