Simultaneous quantitative analysis of N-acylethanolamides in clinical samples

Identification of the oleic acid ethanolamide (OEA) isomer cis-vaccenic acid ethanolamide (VEA) as a highly abundant 18:1 fatty acid ethanolamide in blood plasma from rats and humans

“…The measurement of 20 human plasma samples resulted in a range of 1.73-3.03 ng mL −1 of VEA with an average of 2.33 ± 0.43 ng mL −1 and a concentration of 3.66-10.09 ng mL −1 for OEA with an average of 5.75 ± 1.55 ng mL − 1 . Concentrations of OEA are higher compared to literature data with 1.37 ± 0.43 ng mL −1 (n = 23) [41] and 2.1 ± 0.1 ng mL −1 [42]. Neither PeEA nor the trans-isomers EEA, tVEA, and tPeEA could be detected in the analyzed plasma samples, although cis/trans-isomerization of fatty acids is possible Table 1 Chemical shifts of the 1 H-NMR experiment for the synthesized oleic acid ethanolamide (OEA), elaidic acid ethanolamide (EEA), cis-vaccenic acid ethanolamide (VEA), trans-vaccenic acid ethanolamide (tVEA), cis-petroselinic acid ethanolamide (PeEA), and trans-petroselinic acid ethanolamide (tPeEA).…”

A quantitiative LC-MS/MS method for the measurement of arachidonic acid, prostanoids, endocannabinoids, N-acylethanolamines and steroids in human plasma

“…The Folch extraction (as used in GC-MS analysis of FBS) followed by SPE clean up did not allow the efficient recovery of PEA and SEA in plasma samples of humans or rodents. Therefore, we precipitated plasma proteins using ACN or cold acetone, as previously reported [26,27,32].…”

“…It has been widely used for the analysis of ECs and similar lipids [24][25][26][27][28]. However, it has only recently been used for the analysis of steroids [29][30][31].…”

The endocannabinoid system

“…It has been suggested that inactivation of FAAH can modulate 2-AG tissue levels as well, either up or down, depending on the location [45]. Studies in human volunteers with FAAH inhibitors confirmed increased NAE levels, including that of AEA, N-oleoyl ethanolamide (OEA) and N-palmitoylethanolamide (PEA) [46]. However, in a recent phase II clinical trial in patients with osteoarthritic knee pain, the FAAH inhibitor PF-04457845 failed to show any effect [47 & ,48].…”