Xia Wei, Liu Shu-Qi, Zhang Wen-Qing, Luo Guo-An
Department of Chemistry, East China University of Science and Technology, Shanghai, China.
J Asian Nat Prod Res. 2008 Sep-Oct;10(9-10):857-65. doi: 10.1080/10286020802144685.
A pectic polysaccharide SDA was obtained from the boiling water extract of mulberry leaves. It consisted of rhamnose, arabinose, xylose, glucose, galactose, and galacturonic acid units in the molar ratio of 5:4:1:2:6:38. Its molecular weight was determined to be 1.5 x 10(4) by high-performance gel filtration chromatography. A combination of linkage analysis, partial acid hydrolysis, ESIMS, (1)H-NMR, and (13)C-NMR spectral analyses revealed its structural features. It was found that SDA possessed an alpha-(1 --> 4)-galacturonan backbone with some insertions of (1 --> 2) Rha residues, with the side chains attached to the O-3 or O-2 position of GalA residues, or the O-4 position of 1,2-linked Rha residues. The side chains contained branched (1 --> 5) linked arabinan, branched (1 --> 3) linked rhamman, linear (1 --> 4) linked xylan, linear (1 --> 4) linked glucan, and linear (1 --> 2) linked galactan. SDA was a new acidic polysaccharide isolated from mulberry leaves for the first time.
一种果胶多糖SDA是从桑叶的沸水提取物中获得的。它由鼠李糖、阿拉伯糖、木糖、葡萄糖、半乳糖和半乳糖醛酸单元组成，摩尔比为5:4:1:2:6:38。通过高效凝胶过滤色谱法测定其分子量为1.5×10⁴。通过连接分析、部分酸水解、电喷雾离子化质谱（ESIMS）、¹H-核磁共振（¹H-NMR）和¹³C-核磁共振（¹³C-NMR）光谱分析相结合揭示了其结构特征。发现SDA具有α-(1→4)-半乳糖醛酸聚糖主链，带有一些(1→2)鼠李糖残基插入，侧链连接到半乳糖醛酸残基的O-3或O-2位置，或1,2-连接的鼠李糖残基的O-4位置。侧链包含分支的(1→5)连接的阿拉伯聚糖、分支的(1→3)连接的鼠李聚糖、线性的(1→4)连接的木聚糖、线性的(1→4)连接的葡聚糖和线性的(1→2)连接的半乳聚糖。SDA是首次从桑叶中分离得到的一种新型酸性多糖。
