School of Agriculture and Biology, Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai 200240, China.
Int J Biol Macromol. 2013 May;56:76-82. doi: 10.1016/j.ijbiomac.2013.01.005. Epub 2013 Jan 14.
The chemical structure of a water-soluble pectic polysaccharide (sterculia APS) isolated from boat-fruited sterculia seeds (Semen Sterculiae Lychnophorae) was elucidated using partial acid hydrolysis, methylation analysis and 1D/2D nuclear magnetic resonance (NMR) spectroscopy. The results of partial acid hydrolysis revealed that sterculia APS contained galacturonic acids and rhamnose units in the backbone, and arabinose, galactose and xylose residues in the branched chains. Combined the methylation analysis results with NMR spectroscopy, a possible structure of APS was proposed as follow: the backbone consisted of the homogalacturonan (HG) named "smooth" regions by linear linkage of 1,4-α-D-GalpA, and the rhamnogalacturonan-I (RG-I) called "hairy" ones by the linkage of →4)-α-D-GalpA-(1→2)-α-L-Rhap-(1→partially substituted at O-4 of rhamnose units. The GalpA residues were partially methyl esterified and O-acetylated on C-2 and/or C-3. The side chains were mainly composed of araban and arabinogalactan by the linkages of T-, 1,3-, 1,5-L-Araf and T-, 1,4-, 1,6-, 1,3,6-, 1,3,4-D-Galp, attached to O-4 of the backbone rhamnose units.
从船果瘦果种子（Semen Sterculiae Lychnophorae）中分离得到的一种水溶性果胶多糖（蓖麻 APS）的化学结构，通过部分酸水解、甲基化分析和 1D/2D 核磁共振（NMR）光谱得到阐明。部分酸水解的结果表明，蓖麻 APS 的主链含有半乳糖醛酸和鼠李糖单元，支链含有阿拉伯糖、半乳糖和木糖残基。结合甲基化分析结果和 NMR 光谱，提出了 APS 的可能结构如下：主链由均半乳糖醛酸（HG）组成，通过 1,4-α-D-GalpA 的线性连接命名为“光滑”区域，鼠李半乳糖醛酸-I（RG-I）通过→4）-α-D-GalpA-（1→2）-α-L-Rhap-（1→的连接命名为“毛茸茸”区域，部分在鼠李糖单元的 O-4 上取代。GalpA 残基部分甲酯化并在 C-2 和/或 C-3 上乙酰化。侧链主要由阿拉伯聚糖和阿拉伯半乳聚糖组成，通过 T-、1,3-、1,5-L-Araf 和 T-、1,4-、1,6-、1,3,6-、1,3,4-D-Galp 的键连接，连接到主链鼠李糖单元的 O-4 上。
