中文摘要：

目的以海藻海蒿子为原料制备褐藻糖胶，并对不同的提取、分离方法进行比较，对多糖的组成和结构进行初步分析。方法海蒿子脱脂干粉分别经水提取和酸提取以获得粗多糖，粗多糖分别经乙醇沉淀法和CaCl2沉淀法进行纯化。选取多糖组分F4用Q—Sepharose Fast Flow和Sephadex G-200凝胶柱进行分级分离，高效凝胶渗透色谱法（HPGPC）鉴定纯度及相对分子质量，气相色谱分析多糖的中性单糖组成。结果F4经分级分离得到3个级分：P1、P2和P3。P1、P2和P3均为均一组分，相对分子质量分别为：494400、61500和167600；P1由岩藻糖、木糖、甘露糖、葡萄糖和半乳糖构成，摩尔百分比43．4：33．3：6．2：4．3：12．8；P2由岩藻糖、木糖、甘露糖和半乳糖构成，摩尔百分比44．4：15．1：23．8：16．7；P3由岩藻糖、木糖和半乳糖构成，摩尔百分比68．9：3．7：27．4。结论P1、P2和P3的单糖含量均以岩藻糖为主，但其他单糖组成有较大差别。

英文摘要：

Objective Fucoidans from algae Sargassum pallidum were prepared and the composition and structure of the polysaccharides were elucidated. Methods Fucoidans were extracted and purified by different methods. The polysaccharide F4 was separated by chromatography on a Q-Sepharose Fast Flow column and a Sephadex G-200 column. The purity and molecular weight of polysaccharides were identified by HPGPC. The monosaccharide composition in the polysaccharides was analyzed by GC. Results Three polysaccharide fractions P1, P2, and P3 were obtained from F4. The molecular weight of P1, P2, and P3 were 494 400, 61 500, and 167 600, respectively. GC Analysis showed that all the content of monosaccharide of fucose in P1, P2, and P3 were the highest. P1 was composed of fucose, Xylose, mannose, glucose,and galactose with a molar percentage ratio of 43.4 ： 33.3 ： 6.2 ：4.3 ： 12.8; P2 was composed of fucose, xylose, mannose, and galactose with a ratio of 44.4 ： 15.1 ： 23.8 ： 16.7; and P3 was composed of fucose, xylose, and galactose with a ratio of 68. 9 ： 3.7 ： 27.4. Conclusion The three polysaccharides are mainly composed of fucose, while the other monosaccharides are very different.