稻叶半乳糖脂的分离纯化及脂肪酸组成分析

EXTRACTION AND PURIFICATION OF RICE LEAF GALACTOLIPIDS AND ANALYZATION OF THEIR FATTY ACID COMPOSITION

通过溶剂系统的选择，建立了用硅胶柱层析、薄层层析和反相高效液相色谱分离纯化稻叶中ＭＧＤＧ和ＤＧＤＧ的方法．该方法也适用于其它植物叶中半乳糖脂的分离纯化．硅胶柱层析在除去大量色素和中性脂方面效率较高，反相ＨＰＬＣ适于制备少量的标准ＭＧＤＧ和ＤＧＤＧ纯品．通过专一性脂肪酶水解和碱水解，并经ＨＰＬＣ分析，水稻ＭＧＤＧ和ＤＧＤＧ中α－亚麻酸（１８３脂肪酸）的含量占不饱和脂肪酸总量的９６％以上，不含有１６３脂肪酸，由此可以确定水稻属于１８３植物．在ＭＧＤＧ的甘油部分Ｃ－１位上总是连接α－亚麻酸，而Ｃ－２位上除大部分连接α－亚麻酸外，还连接有少量的１８２，１８１和１６１脂肪酸；在ＤＧＤＧ的Ｃ－１和Ｃ－２位除大部分连接１８３脂肪酸外。

A method of extraction and purification of monogalactosyldiglyceride (MGDG) and digalactosyldiglyceride (DGDG) in rice leaves was gained based on silica gel column chromatography,TLC and reversed phase HPLC.Most pigments and neutral lipids could be removed from total lipids with silica gel column chromotography,but reversed phase HPLC was only suitable for the treatment of a small amount of pured MGDG and DGDG preparation.The results of HPLC analysis showed that over 96% unsaturated fatty acid was α linolenic acid (18∶3),and no 16∶3 fatty acids was found,when the MGDG and DGDG of rice leaves were treated with mild alkaline deacylation or specific lipases.It suggested that rice should belong to 18∶3 plant.It was also found that 18∶3 fatty acid of the MGDG predominated in the C 1 position,while 18∶2,18∶1 and 16∶1 fatty acids were restricted only to the C 2.No specific marked distribution of fatty acids was found in the DGDG.