桑叶多糖PMP11的分离纯化及结构初探

Separation, Purification and Preliminary Structure Analysis of Polysaccharide PMP11 from Morus alba

目的:从桑叶中分离纯化获得均一多糖PMP11,并研究其组成及初步结构。方法:桑叶经热水提取乙醇分级沉淀、脱蛋白、脱色、DEAE-52纤维素和Sephadex G-100柱层析,得到一个均一多糖组分PMP11;采用GC、HPLC、IR、NMR、Smith降解和糖醛酸的还原等方法分析其组成和初步结构。结果:PMP11主要由鼠李糖、半乳糖醛酸和葡糖醛酸组成,其摩尔比为鼠李糖∶半乳糖醛酸∶葡糖醛酸=2.27∶1.59∶1;PMP11的主链主要是以β-1→2糖苷键及β-1→3糖苷键连接的鼠李糖,侧链主要是以β-1→2糖苷键及β-1→4糖苷键连接的葡糖醛酸和半乳糖醛酸。结论:本试验首次分析桑叶多糖PMP11的初步结构,可为桑叶多糖的进一步研究提供依据。

OBJECTIVE： To isolate polysaccharide PMPll from Morus alba, and to study the composition and preliminary structure of polysaccharide PMP11. METHODS： M. alba were extracted by boiling water. The polysaccharide in the filtrate was precipitated fractionally by alcohol. The protein in the product was removed by TCA and was further purified by DEAE ion exchange cellulose （DEAE-52） and SephadexG-100. Then polysaccharide PMP11 was obtained. The composition and preliminary structure of polysaccharide PMP11 were analyzed through IR, GC, HPLC, ^1H-NMR, Smith degradation and uronic acid reduction, etc. RESULTS： Polysaccharide PMP11 was made up of rhamnose, galactose acid and glycuronic acid with the molarity proportion of 2.27： 1.59： 1; the main chain of polysaccharide PMPll was made up of rhamnose being connected via β-1→2 and β-1→3 linkage; the side chains were galactose and glycuronic acid being connected via β-1→2 and β-1→4 linkage. CONCLUSION： The preliminary structure of polysaccharide PMP11 is analyzed in the study for the first time. The study can provide theory evidence for further study of polysaccharides from M. alba.