ASSIGNMENT OF MONOUNSATURATED AND POLYUNSATURATED FATTY-ACIDS IN LIPIDS OF TISSUES AND BODY-FLUIDS

Semi-selective 800 MHz H-1, C-13 HSQC NMR spectra provide ultra-high r esolution of the double bond region of lipid spectra and the possibili ty of assigning signals to individual unsaturated fatty acid side-chai ns such as 18:1, 18:2 or 20:4 even in complex mixtures such as bioflui ds. Additional HSQC-TOCSY spectra correlate the direct double bond sig nals with the adjacent allylic high-field proton signals of mono- and polyunsaturated fatty acids. These signals show characteristic chemica l shifts to differentiate unsaturated fatty acids such as 18:1, 18:2 a nd 20:4 (or others). By this means, the amount of each type of unsatur ated fatty acid can be quantified. Typical lipid spectra of body fluid s (blood plasma and cerebrospinal fluid) and pig brain (grey and white matter) are presented and discussed with respect to the use of this t echnique for diagnostic purposes. (C) 1998 John Wiley & Sons, Ltd.