酶法降解白及粗多糖  

Enzymatic degradation of crude polysaccharide from Bletilla striata

作　　者：洪彤彤[1] 张秋菊[1] 贺少龙[1] 刘艳华[1,2] 隋宏[1,2] 王文苹[1,2] 

机构地区：[1]宁夏医科大学药学院,宁夏银川750004 [2]宁夏回药现代化工程技术研究中心,宁夏银川750004

出　　处：《中成药》2014年第11期2285-2290,共6页Chinese Traditional Patent Medicine

基　　金：2011年国家自然科学基金项目(81160521)

摘　　要：目的用酶法降解白及粗多糖制备低分子质量多糖。方法用纤维素酶、β-葡聚糖酶、β-葡萄糖苷酶降解水提醇沉制得白及粗多糖;经梯度乙醇分级沉淀收集不同分子质量段的还原糖,测定其黏均分子质量和总糖量,计算还原糖得率以及它们的紫外和红外光谱图。结果最佳酶解条件为配制20 mg/mL的白及多糖溶液并调节pH为5.0,加入250 U/mg的纤维素酶液,45℃保温振荡5 h,煮沸5 min灭活酶;用体积分数50%、70%、90%(mL/mL)的乙醇分级沉淀后可得黏均分子质量约为5.3、3.7、1.1 kDa的白及多糖,它们的还原糖和总糖量约为30%和85%,紫外和红外光谱图无明显差异。结论酶法降解白及粗多糖得到不同分子质量段多糖可供进一步研究和应用。AIM To obtain the low-molecular-weight polysaccharides from crude Bletilla striata （BSP） by enzymatic degradation.METHODS Crude polysaccharides that extracted by aqueous extraction and ethanol precipitation were further degraded by cellulase,β-glucanase and β-glucosidase.The reducing sugar produced by ethanol gradient fractionation was collected and their viscosity-average molecular weight and total sugar content were measured,their yield rate was calculated,and their UV and IR spectrometry were analyzed as well.RESULTS The optimum degradation conditions consisted of adding 250 U/mg cellulose into 20 mg/mL crude BSP at pH 5.0,and keeping the vibration at 45 ℃ for 5 h,then boiling for 5 min to deactivate.BSP with viscosity-average molecular weight of 5.3 kDa,3.7 kDa,and 1.1 kDa were collected respectively by stepwise precipitation using the volume fractions of 50％,70％ and 90％ （mL/mL） ethanol.The reducing sugar and total sugar contents of BSP fractions were 33％ and 85％,respectively,and no significant difference was found in the UV or FTIR spectra.CONCLUSION Enzymatic degradation can convert BSP into low-molecular-weight polysaccharides for further study.

关 键 词：白及 粗多糖 酶法降解 黏均分子质量 分级 醇沉 

分 类 号：R284.2[医药卫生—中药学]