水溶性壳聚糖降血脂作用的化学机理(Ⅰ)──水溶性壳聚糖及其衍生物对胆酸盐的结合能力研究

Chemical Mechanism of the Anti-hyperlipoidenmia Effect of Water-soluble Chitosan(Ⅰ)──Capacities of Water-soluble Chitosan and Its Derivativesto Bind Taurocholate and Glycocholate as Bile Salts

通过壳聚糖氧化裂解 ,制备了分子量为 80 0 0的水溶性壳聚糖 ,并通过烷基化反应合成了二乙氨乙基壳聚糖、二甲氨基 ( 1 -甲基 )乙基壳聚糖及二乙基甲基铵乙基壳聚糖 .在体外测定了水溶性壳聚糖及其衍生物对胆酸盐 (牛磺胆酸钠和甘氨胆酸钠 )的结合能力及其影响因素 .结果表明 ,水溶性壳聚糖结合胆酸盐的能力主要取决于其阳离子化程度 .修饰后的壳聚糖结合胆酸盐的能力增强 ,说明引入更多的胺基或铵基有利于对胆酸盐的结合 .

Chitosan in a range of molecular weight has the anti-hyperlipoidenmia effect owing to its ability to bind bile salt in gastrointestinal tract. Water-soluble chitosan with molecular weight of 8 000 was prepared and reacted with diethylaminoethyl chloride and dimethylamino(1-methyl)ethyl chloride to afford diethylaminoethyl chitosan(DEAE-chitosan) and dimethylaminoisopropyl chitosan(DMAIP-chitosan) respectively. DEAE-chitosan was methylated with methyl iodide to give the ammonium-containing chitosan(DEMAE-chitosan). The binding capacities of the water-soluble chitosan and its derivatives to taurocholate and glycocholate as bile salts were investigated in vitro. Through changing the factors of bile salts concentration, medium pH value, deacetylation degrees of the soluble chitosan and so on the influence of the binding capacity was studied on soluble chitosan to bile salts. The results indicated that the binding capacity of the soluble chitosan to bile salts was mainly depended on its cationic structure. The taurocholate binding capacities of chitosan, DEAE-chitosan at an initial taurocholate concentration of 10 mmol/L are 2\^04 and 2.83 mmol/g. The binding capacities are increased about 40% by the latter. The glycocholate binding capacities of chitosan, DEMAE-chitosan at an initial glycocholate concentration of 10 mmol/L are 1.65 and 3.34 mmol/g. The results indicated that the introduction of amino or ammonium groups onto chitosan could increase the binding capacity to bile salts.