†College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P. R. China.
‡Institute of Agro-Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210095, P. R. China.
J Agric Food Chem. 2015 Apr 8;63(13):3454-63. doi: 10.1021/acs.jafc.5b01086. Epub 2015 Mar 31.
A novel cell-bound exopolysaccharide (c-EPS) was isolated from Lactobacillus helveticus MB2-1 by ultrasonic extraction, anion exchange, and gel filtration chromatography before being structurally characterized. The c-EPS is a heteropolysaccharide with an average molecular weight of 1.83 × 10(5) Da and is composed of glucose, mannose, galactose, rhamnose, and arabinose at a molar ratio of 3.12:1.01:1.00:0.18:0.16. Methylation analysis and nuclear magnetic resonance analysis revealed that the c-EPS is a linear glucomannogalactan containing repeating units of → 6)-β-D-Manp-(1 → 3)-β-D-Glcp-(1 → 3)-β-D-Glcp-(1 → 3)-β-D-Glcp-(1 → 4)-α-D-Galp-(1 → and trace amounts of Rhap-(1 → and (1 → 4)-Arap residues. Complex formation with Congo red demonstrated a triple-strand helical conformation for the c-EPS. Scanning electron microscopy of the c-EPS revealed many regular feather-like structural units. Topographical examination of c-EPS by atomic force microscopy revealed that the c-EPS formed rounded-to-spherical lumps with different sizes and chain formations. Furthermore, preliminary in vitro tests revealed that c-EPS significantly inhibited the proliferation of HepG-2, BGC-823, and especially HT-29 cancer cells.
从瑞士乳杆菌 MB2-1 中分离出一种新型的细胞结合胞外多糖（c-EPS），通过超声提取、阴离子交换和凝胶过滤色谱进行分离，然后对其结构进行表征。该 c-EPS 是一种杂多糖，平均分子量为 1.83×10(5)Da，由葡萄糖、甘露糖、半乳糖、鼠李糖和阿拉伯糖组成，摩尔比为 3.12:1.01:1.00:0.18:0.16。甲基化分析和核磁共振分析表明，c-EPS 是一种含有重复单元的线性葡甘露半乳糖聚糖，→ 6）-β-D-Manp-（1 → 3）-β-D-Glcp-（1 → 3）-β-D-Glcp-（1 → 3）-β-D-Glcp-（1 → 4）-α-D-Galp-（1 → 和痕量的 Rhap-（1 → 和（1 → 4）-Arap 残基。刚果红与 c-EPS 的复合物形成表明 c-EPS 具有三股螺旋构象。c-EPS 的扫描电子显微镜观察显示出许多规则的羽毛状结构单元。原子力显微镜对 c-EPS 的形貌观察表明，c-EPS 形成了不同大小和链形成的圆形至球形块状物。此外，初步的体外试验表明，c-EPS 显著抑制了 HepG-2、BGC-823 和特别是 HT-29 癌细胞的增殖。
