塔拉豆多糖研究

STUDY ON POLYSACCHARIDE IN TARA SEED

对我国云南５ 个产地的塔拉豆多糖含量测定表明：内胚乳含多糖７９ ％ ～８６ ％ （ 干基计） ，带壳内胚乳含多糖３４ ％ ～４３ ％ （ 干基计） ，对提纯的多糖样品进行了ＧＣ、ＨＰＧＰＣ、ＩＲ 及１３ＣＮＭＲ 分析，结果表明塔拉豆多糖含Ｄ半乳糖、Ｄ葡萄糖、Ｄ甘露糖，其摩尔比为１－００∶０－３３∶３－０３ ，其数均分子量为Ｍｎ ＝ １ ．８２ ×１０４ ，分散度ｄ ＝ １ ．０５ 。ＩＲ、１３ＣＮＭＲ谱图测定推断：塔拉豆多糖主链由β（１ →４） 键连结的Ｄ吡喃型甘露糖单元及少量Ｄ吡喃型葡萄糖单元所组成。Ｄ半乳糖单元可能按（１ →６） 键附于主链中甘露糖单元上。

In this paper,the contents of polysaccharides in tara ( Caesalpinia spinosa) seeds from 5 districts in Yunnan Province were determined.Results showed that contents of polysaccharides amounted to 79 %～86 % in endosperms and 34 %～43 % in endosperms with shell respectively (on dry basis). Purified polysaccharide was identified by GC, HPGPC ,IR and 13 C NMR.Results indicated that tara seed polysaccharide composed of D galactose,D glucose and D mannose units in molar ratio 1.00∶0.33∶3.03,with mean molecular weight Mn=1.82×10 4,dispersity d=1.05.By means of IR 13 C NMR,the structure of the polysaccharide was elucidated that it had a main chain mainly consisted of (1→4)linked D mannopyranosyl units with small amount of D glucopyranosyl units,and a side chain possibly consisted of (1→6)linked D galactosyl units attached to D mannose units of the main chain.