Sébédio J L, Juanéda P, Grégoire S, Chardigny J M, Martin J C, Ginies C
INRA, Unité de Nutrition Lipidique, Dijon, France.
Lipids. 1999 Dec;34(12):1319-25. doi: 10.1007/s11745-999-0484-3.
Rats were fed a fat-free diet for 2 wk. After this period, while maintaining the animals on the same diet, the rats were given intragastrically 180 mg per day of a mixture of conjugated linoleic acids (CLA) as triacylglycerols. Gas chromatography mass spectrometry (GC-MS) analyses of this mixture, as well as hydrazine reduction and GC-MS and GC-Fourier transform infrared analyses of the resulting monoenes, revealed the presence of two major isomers, the 9c,11t- and the 10t,12c-18:2 accompanied by smaller amounts of the 8t, 10c and the 11c, 13t-18:2 isomers. Minor quantities of cis,cis and trans,trans conjugated isomers also were detected. The total fatty acid methyl esters from the liver lipids were fractionated by reversed-phase high-performance liquid chromatography, and the fraction containing the 20:4 isomers was further fractionated by silver nitrate thin-layer chromatography. A band containing two 20:4 conjugated isomers was submitted to hydrazine reduction and the resulting monoenes analyzed by GC-MS as dimethyl-oxazoline derivatives. The two conjugated isomers were tentatively identified as 5c,8c, 11c, 13t-20:4 and 5c,8c,12t,14c-20:4. These could be formed by desaturation and elongation of the 9c,11t- and 10t,12c-18:2 present in the commercial CLA mixture.
大鼠食用无脂饮食2周。在此期间过后，在维持动物相同饮食的情况下，给大鼠每日经胃内给予180毫克作为三酰甘油的共轭亚油酸（CLA）混合物。对该混合物进行气相色谱 - 质谱（GC-MS）分析，以及对所得单烯进行肼还原、GC-MS和GC-傅里叶变换红外分析，结果显示存在两种主要异构体，即9c,11t-和10t,12c-18:2，同时伴有少量的8t,10c和11c,13t-18:2异构体。还检测到少量的顺式,顺式和反式,反式共轭异构体。通过反相高效液相色谱对肝脏脂质中的总脂肪酸甲酯进行分离，含有20:4异构体的馏分再通过硝酸银薄层色谱进一步分离。将含有两种20:4共轭异构体的条带进行肼还原，并将所得单烯作为二甲基恶唑啉衍生物通过GC-MS进行分析。这两种共轭异构体初步鉴定为5c,8c,11c,13t-20:4和5c,8c,12t,14c-20:4。它们可能是由市售CLA混合物中存在的9c,11t-和10t,12c-18:2去饱和和延长形成的。
