Pitfalls in the sample preparation and analysis of N-acylethanolamines[S]

N-acylethanolamines (NAEs) are a group of lipid mediators synthesized in response to a number of physiological and pathological stimuli. Because of the low tissue concentrations of NAEs, analyses often include liquid extraction followed by solid-phase extraction and subsequent quantitation by LC/MS or GC/MS. Reported levels of NAEs vary considerably, however, and often no explanation is given for these discrepancies. Brought on by difficulties encountered during method development, the effects of using four different brands of silica-containing solid phase extraction (SPE) columns and five different brands of chloroform for sample preparation were investigated. Considerable variation in the retention and recoveries of seven NAEs and 2-arachidonoylglycerol existed between the SPE columns. Furthermore, it was found that some chloroforms contained quantifiable amounts of N-palmitoylethanolamine and N-stearoylethanolamine. Finally, it was found that use of one of the chloroforms resulted in a loss of N-oleoylethanolamine from solution due to addition of chlorine to the ω-9 bond. The identity of this reaction product was confirmed by LC-MS/MS and NMR. It is recommended that these aspects of sample preparation and analysis should be thoroughly validated during method development and the relevant information on specific brands used be reported in future communications in order to better estimate the validity of reported quantitative data.

[1]  A. Miolo,et al.  Effects of palmitoylethanolamide on immunologically induced histamine, PGD2 and TNFalpha release from canine skin mast cells. , 2010, Veterinary immunology and immunopathology.

[2]  B. Barroso,et al.  Simultaneous quantitative analysis of N-acylethanolamides in clinical samples. , 2009, Analytical biochemistry.

[3]  D. Tsikas,et al.  Targeted stable-isotope dilution GC-MS/MS analysis of the endocannabinoid anandamide and other fatty acid ethanol amides in human plasma. , 2009, Journal of chromatography. B, Analytical technologies in the biomedical and life sciences.

[4]  H. Hansen,et al.  N-acylethanolamines, anandamide and food intake. , 2009, Biochemical pharmacology.

[5]  J. Ozer,et al.  Endogenous ethanolamide analysis in human plasma using HPLC tandem MS with electrospray ionization. , 2009, Journal of chromatography. B, Analytical technologies in the biomedical and life sciences.

[6]  S. Petrosino,et al.  From endocannabinoid profiling to 'endocannabinoid therapeutics'. , 2009, Current opinion in chemical biology.

[7]  U. Kristiansen,et al.  Ketogenic diet is antiepileptogenic in pentylenetetrazole kindled mice and decrease levels of N-acylethanolamines in hippocampus , 2009, Neurochemistry International.

[8]  D. Piomelli,et al.  Targeted enhancement of oleoylethanolamide production in proximal small intestine induces across-meal satiety in rats. , 2008, American journal of physiology. Regulatory, integrative and comparative physiology.

[9]  R. Capasso,et al.  Gastrointestinal Regulation of Food Intake: General Aspects and Focus on Anandamide and Oleoylethanolamide , 2008, Journal of neuroendocrinology.

[10]  H. Hansen,et al.  Endocannabinoids and Nutrition , 2008, Journal of neuroendocrinology.

[11]  Christian Skonberg,et al.  Influence of dietary fatty acids on endocannabinoid and N-acylethanolamine levels in rat brain, liver and small intestine. , 2008, Biochimica et biophysica acta.

[12]  N. Stella,et al.  An optimized GC-MS method detects nanomolar amounts of anandamide in mouse brain. , 2008, Analytical biochemistry.

[13]  K. Lambertsen,et al.  Changes in brain levels of N‐acylethanolamines and 2‐arachidonoylglycerol in focal cerebral ischemia in mice , 2007, Journal of neurochemistry.

[14]  D. Barrett,et al.  Quantitative profiling of endocannabinoids and related compounds in rat brain using liquid chromatography-tandem electrospray ionization mass spectrometry. , 2007, Analytical biochemistry.

[15]  S. Weintraub,et al.  Quantification of endocannabinoids in rat biological samples by GC/MS: technical and theoretical considerations. , 2006, Prostaglandins & other lipid mediators.

[16]  A. Hohmann,et al.  Rapid Broad-Spectrum Analgesia through Activation of Peroxisome Proliferator-Activated Receptor-α , 2006, Journal of Pharmacology and Experimental Therapeutics.

[17]  T. Honda,et al.  Analyses of Anandamide and Endocannabinoid-like Compounds Using Collision-induced Dissociation in Fast Atom Bombardment Ionization-Mass Spectrometry and Gas Chromatography/Chemical Ionization-Mass Spectrometry , 2003, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[18]  L. Marnett,et al.  Analysis of endocannabinoids by Ag+ coordination tandem mass spectrometry. , 2003, Analytical biochemistry.

[19]  W. Griffiths.  Tandem mass spectrometry in the study of fatty acids, bile acids, and steroids. , 2003, Mass spectrometry reviews.

[20]  H. Schmid,et al.  Cell signaling by endocannabinoids and their congeners: questions of selectivity and other challenges. , 2002, Chemistry and physics of lipids.

[21]  A. Finazzi-Agro’,et al.  Binding, degradation and apoptotic activity of stearoylethanolamide in rat C6 glioma cells. , 2002, The Biochemical journal.

[22]  C. Breivogel,et al.  Levels, Metabolism, and Pharmacological Activity of Anandamide in CB1 Cannabinoid Receptor Knockout Mice , 2000 .

[23]  H. Hansen,et al.  N-Acylethanolamines and precursor phospholipids - relation to cell injury. , 2000, Chemistry and physics of lipids.

[24]  D. Piomelli,et al.  Reversal of Dopamine D2 Receptor Responses by an Anandamide Transport Inhibitor , 2000, The Journal of Neuroscience.

[25]  D. Piomelli,et al.  Quantification of bioactive acylethanolamides in rat plasma by electrospray mass spectrometry. , 2000, Analytical biochemistry.

[26]  R. Krebsbach,et al.  A sensitive endocannabinoid assay. The simultaneous analysis of N-acylethanolamines and 2-monoacylglycerols. , 2000, Chemistry and physics of lipids.

[27]  C. Breivogel,et al.  Levels, metabolism, and pharmacological activity of anandamide in CB(1) cannabinoid receptor knockout mice: evidence for non-CB(1), non-CB(2) receptor-mediated actions of anandamide in mouse brain. , 2000, Journal of neurochemistry.

[28]  P. Kiviranta-Pääkkönen,et al.  Simultaneous Isomerization and Etherification of Isoamylenes , 1999 .

[29]  V. Di Marzo,et al.  Analysis of cannabinoid receptor binding and mRNA expression and endogenous cannabinoid contents in the developing rat brain during late gestation and early postnatal period , 1999, Synapse.

[30]  T. Bisogno,et al.  Brain regional distribution of endocannabinoids: implications for their biosynthesis and biological function. , 1999, Biochemical and biophysical research communications.

[31]  H. Homma,et al.  Liquid chromatographic-atmospheric pressure chemical ionization mass spectrometric determination of anandamide and its analogs in rat brain and peripheral tissues. , 1997, Journal of chromatography. B, Biomedical sciences and applications.

[32]  J. Trottier,et al.  Book Review: Mass Spectrometry: Principles and Applications. E. de Hoffman, J. Charette and W. Stroobant. Wiley, Chichester 1996. ISBN 0 471 96697 5 , 1997 .

[33]  D. Piomelli,et al.  Analysis of anandamide, an endogenous cannabinoid substance, and of other natural N-acylethanolamines. , 1995, Prostaglandins, leukotrienes, and essential fatty acids.

[34]  A. Krause,et al.  Reaction Equilibria in the Synthesis of 2-Methoxy-2-methylbutane and 2-Ethoxy-2-methylbutane in the Liquid Phase , 1994 .

[35]  D. Gibson,et al.  Isolation and structure of a brain constituent that binds to the cannabinoid receptor. , 1992, Science.

[36]  H. Maag.  Fatty acid derivatives: Important surfactants for household, cosmetic and industrial purposes , 1984 .

[37]  W. Yu,et al.  Photolysis of Chloroform in the Presence of Ethane at 25°C , 1970 .

[38]  J. Folch,et al.  A simple method for the isolation and purification of total lipides from animal tissues. , 1957, The Journal of biological chemistry.