Etude de la desaturation et de l'elongation in vivo d'isomeres geometriques de l'acide linolenique

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Identification d'un acide gras polyinsaturé atypique présent dans le foie de rats ayant ingéré de l'huile de lin chauffée

National audienc

Trans isomers of long-chain n-3 polyunsaturated fatty acids in tissue lipid classes of rats fed with heated linseed oil

International audienc

Trans isomers of long-chain n-3 polyunsaturated fatty acids in tissue lipid classes of rats fed with heated linseed oil

International audienc

Occurence of geometrical isomers of eicosapentaenoic and docosahexaenoic acids in liver lipids of rats fed heated linseed oil

Mono trans geometrical isomers of 20:5 n-3 and 22:6 n-3 were detected in liver lipids of rats fed heated linseed oil. The isomers were identified as being 20:5 h5c,8c,11c,14c,17t and 22:6 h4c,7c,10c,13c,16c,19t. These fatty acids were isolated as methyl esters by preparative high-performance liquid chromatography IHPLC) on reversed phase columns followed by silver nitrate thin layer chromatography (AgNO3-TLC). The structures were identified using partial hydrazine reduction, AgNO3-TLC of the resulting monoenes, oxidative ozonolysis of each monoene band, and gas-liquid chromatography (GLC) of the resulting dimethyl esters and monomethyl esters. Fourier-transform-infrared spectrometry confirmed the trans geometry in isolated 20:5 and 22:6 isomers. The isomers of eicosapentaenoic and docosahexaenoic acids in liver lipids probably resulted from desaturation and elongation of 18:3 h9c,12c,15t, a geometrical isomer of linolenic acid present in the heated dietary oil