改性柑橘果胶的制备、表征及抗癌活性

采用琼脂糖凝胶电泳、比旋度测试、HPSEC-RID、IR、¹H NMR、¹³C NMR、高碘酸氧化及甲基化分析等手段对改性柑橘果胶(MCP)进行了分析, 结果表明, MCP是一种均一性多糖, 分子量约为21000~66000, 糖醛酸质量分数为81.0%, 酯化度为2.13%. MCP的中性单糖残基主要包括鼠李糖(Rha)、阿拉伯糖(Ara)、木糖(Xyl)和半乳糖(Gal)等, 其摩尔比约为1.0∶1.5∶1.4∶1.3, 主链包括HG和RG, 分支结构含有末端Gal, Xyl和Ara. 选用3种小鼠移植性肿瘤模型对MCP的抗肿瘤生长活性进行研究. 结果表明, MCP对肝癌H22细胞有较强抑制作用, 高剂量下抑制率可达47.8%; 对宫颈癌U14细胞的抑制率在高剂量及中等剂量下分别达到36.5%和38.5%; 对肉瘤S180没有抑制活性. MCP的抗肝癌和抗宫颈癌活性为首次发现.

Modified Citrus Pectin: Preparation, Characterization and Anti-cancer Activities

Agarose gel electrophoresis, specific rotatory, HPSEC-RID, IR, 1H NMR, 13C NMR, periodate oxidation, GC-MS and methylation analysis were applied to investigate the homogeneity, chemical properties and structural features of modified citrus pectin(MCP). Results demonstrated that MCP was a homogeneous polysaccharide. Its molecular weight ranged from 21000 to 66000; the content of galacturonic acid was 81.0% and the degree of esterification was 2.13%. MCP contains Gal, Xyl, Rha and Ara; their molar ratio was 1.0∶1.5∶1.4∶1.3. Methylation analysis results confirmed that MCP had neutral sugar residues composed of Xyl, Ara and terminal Gal. Heptoma H22 was significantly inhibited by MCP and the inhibitor rate was 47.8%(n=10, p<0.01) at high-dose level(4 mg/kg). MCP also demonstrated anti-cervical carcinoma activity in U14 mice model. No anti-cancer activity was observed in Sarcoma 180 group.