桑叶多糖的分离纯化及其抑菌活性研究

为研究大孔树脂分离和纯化桑叶多糖的最佳工艺及抑菌活性。以超声-微波协同提取的桑叶多糖为原料,考察8种不同类型大孔树脂的比吸附量、吸附率及解吸率,筛选出最佳纯化树脂类型为AB-8,对其吸附和解吸条件进行考察和优化,经过单因素试验,确定最优纯化工艺参数,并用牛津杯法考察桑叶多糖纯化前后的抑菌效果。结果显示,最优工艺参数为:上样液浓度为3.0 mg/mL、pH 4.0、上样流速为1.5 BV/h;解吸液乙醇体积分数为65%、pH 6.0、洗脱流速为1.5 BV/h、洗脱体积为90 mL(3.0 BV)。此工艺可将桑叶多糖粗品的纯度由11.34%提高到57.46%,提高4.07倍。抑菌试验结果表明:浓度大于1.0 mg/mL桑叶多糖对大肠杆菌、沙门氏菌、金黄色葡萄球菌的活性均存在不同程度的抑制作用,且纯化后抑菌作用显著增强。

Purification and Antibacterial Activity of Polysaccharide from Mulberry Leaves

In order to study the optimum technology and antibacterial activity of mulberry leaf polysaccharide separated and purified by macroporous resin.Mulberry leaf polysaccharide extracted by ultrasonic-microwave collaboration was used as raw material,the specific adsorption rate,adsorption rate and desorption rate of 8 kinds of macroporous resins were investigated,the best purified resin was selected,the adsorption and desorption conditions were investigated and optimized,the optimum purification process parameters were determined by single factor test,and the bacteriostatic effect of mulberry leaf polysaccharide before and after purification was investigated by Oxford cup method.The results showed that the optimal process parameters were as follows:sample loading solution concentration was 3.0 mg/mL,pH 4.0,sample loading flow rate was 1.5 BV/h.The volume fraction of the desorption liquid ethanol was 65%,pH 6.0,elution velocity was 1.5 BV/h,and elution volume was 90 mL(3.0 BV).Through this process,the purity of crude mulberry leaf polysaccharide was increased from 11.34%to 57.46%and 4.07 times.The bacteriostatic test results showed that the concentration of polysaccharides in mulberry leaves was greater than 1.0 mg/mL,which had different degree of inhibitory effect on the activities of Escherichia coli,Salmonella and Staphylococcus aureus,and the antibacterial effect was significantly enhanced after purification.