当归多糖ASP3的甲基化分析

通过部分酸水解和甲基化分析, 结合GC-MS测试手段, 对当归多糖ASP3的糖链结构进行了研究. 采用0.2 mol/L三氟乙酸(Trifluoroacetic acid, TFA)对ASP3进行了部分酸水解, 对水解前后的多糖组分进行甲基化分析. 结果显示: ASP3的糖残基主要由D-GalpA, D-Galp, L-Araf和L-Rhap组成, 主链由1,4-D-GalpA连接, 形成“光滑区”半乳糖醛酸聚糖, 由1,4-D-GalpA通过O-4位与1,2-; 1,2,4-L-Rhap的O-2位交替连接形成含有较多分支的“毛发区”鼠李半乳糖醛酸聚糖. 58.8%的Rhap残基发生O-4位取代(1,2,4-L-Rhap). 由T-, 1,5-, 1,3,5-Araf和T-, 1,3-, 1,3,6-, 1,4-, 1,4,6-D-Galp聚合形成的阿拉伯半乳聚糖、半乳聚糖以及阿拉伯聚糖是ASP3侧链的主要组成, 通过Rhap残基的O-4位与主链相连.

Methylation Analysis of Polysaccharide ASP3 from Angelica sinensis(Oliv.) Diels

The structural features of polysaccharide ASP3 were studied by partial acid hydrolysis and methylation methods, combined with GC-MS instrument. ASP3 was hydrolyzed with 0.2 mol/L trifluoroacetic acid and methylation analysis method were conducted on the samples. The results indicate that the residues of sugar constituents were mainly D-GalpA, D-Galp, L-Araf and L-Rhap. ASP3 contained the main part of homogalacturonan fragments as "smooth regions" with 1,4-D-GalpA and rhamnogalacturonan segments as "hairy regions". A total of 58.8% Rhap residues in the backbone were substituted at O-4 position by side chains. T-, 1,5-, 1,3,5-Araf and T-, 1,6-, 1,3,6-, 1,4-, 1,4,6-D-Galp were linked as arabinogalactan, galactan and arabinan, which were the mainly constitution of the branch.