Synthesis, isolation, and GC analysis of all the 6,8‐to 13,15‐<i>cis/trans</i> conjugated linoleic acid isomers

Delmonte, Pierluigi; Roach, John A. G.; Mossoba, Magdi M.; Losi, Giuseppe; Yurawecz, M. P.

doi:10.1007/s11745-004-1218-2

Cited by 43 publications

(22 citation statements)

References 16 publications

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“…However, because the difference in R t between the cis 11, trans 13 standard isomer and the unknown ⌬ 11,13-CLA was small (only 0.2 min), time (R t = 28.0 min). Knowing that the four geometrical isomers of a CLA elute with a specifi c order ( cis -trans , transcis , cis -cis , and trans -trans ) when separated on a capillary column with a polar stationary phase ( 32 ), this result fi rst …”

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confidence: 99%

Trans-vaccenate is Δ13-desaturated by FADS3 in rodents

Rioux

Pédrono

Blanchard

et al. 2013

Journal of Lipid Research

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This article is available online at http://www.jlr.org "methyl-end" FA desaturases. Therefore, linoleic acid and ␣ -linolenic acid must be provided by the diet ( 3 ). These dietary essential FAs then serve as precursors for longer PUFAs of the n-6 and n-3 series, including arachidonic acid (20:4 n-6) and docosahexaenoic acid (22:6 n-3) required for many important physiological functions in humans ( 4,5 ). In this PUFA biosynthesis, only "front-end" desaturases ( ⌬ 5-and ⌬ 6-desaturases) are involved to introduce new double bonds between the preexisting double bonds and the carboxyl end of FAs ( 6 ).In 2000, the genomic structure of the fatty acid desaturase (FADS) cluster, located on chromosome 11 in humans, was reported ( 7 ). This cluster includes the FADS1 and FADS2 genes that code, respectively, for the well-known ⌬ 5-and ⌬ 6-desaturases involved in PUFA biosynthesis ( 8-10 ). A third gene was identifi ed on this cluster with high degree of nucleotide sequence homology with both FADS1 (62%) and FADS2 (70%) and was therefore named FADS3. Since its fi rst description in humans ( 7 ), FADS3 has been identifi ed in rats ( 11 ), baboons ( 12 ), mice ( 3 ), and many other mammals showing a similar nucleotide sequence and intron/exon organization ( 12 ). When analyzing the peptide sequence deduced from the FADS3 nucleotide sequence, FADS3 protein was identifi ed as a putative desaturase, according to its similarity with FADS1 and FADS2. Indeed, the predicted structure of FADS3 is composed of an N-terminal cytochrome b5-like domain characterized by a HPGG motif shown to be essential for the ⌬ 6-desaturase activity of FADS2 ( 13 ) QIEHH in the rat) characteristic of front-end-desaturases ( 14 ). According to its amino acid sequence, FADS3 was thereafter supposed to Abstract Fatty acid desaturases play critical roles in regulating the biosynthesis of unsaturated fatty acids in all biological kingdoms. As opposed to plants, mammals are so far characterized by the absence of desaturases introducing additional double bonds at the methyl-end site of fatty acids. However, the function of the mammalian fatty acid desaturase 3 (FADS3) gene remains unknown. This gene is located within the FADS cluster and presents a high nucleotide sequence homology with FADS1 ( ⌬ 5-desaturase) and FADS2 ( ⌬ 6-desaturase). Here, we show that rat FADS3 displays no common ⌬ 5-, ⌬ 6-or ⌬ 9-desaturase activity but is able to catalyze the unexpected ⌬ 13-desaturation of trans -vaccenate. Although there is no standard for complete conclusive identifi cation, structural characterization strongly suggests that the ⌬ 11,13-conjugated linoleic acid (CLA) produced by FADS3 from trans -vaccenate is the trans 11, cis 13-CLA isomer. In rat hepatocytes, knockdown of FADS3 expression specifically reduces trans -vaccenate ⌬ 13-desaturation. Evidence is presented that FADS3 is the fi rst "methyl-end" fatty acid desaturase functionally characterized in mammals. FA desaturases introduce double bonds between defi ned carbons of the fatty acyl chain and catalyze ...

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Section: Downloaded Frommentioning

confidence: 99%

Trans-vaccenate is Δ13-desaturated by FADS3 in rodents

Rioux

Pédrono

Blanchard

et al. 2013

Journal of Lipid Research

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“…Preparations of mixtures containing all 16 possible isomers ranging from 8,10-to 11,13-18:2, obtained by isomerization of commercial CLA with either iodine or p-toluenesulfinic acid as catalyst [12], or with additional 7t,9c-and 12c,14t-18:2 isomers using a procedure involving sigmatropic rearrangements and seleniumcatalysed geometrical isomerization [13], are useful as standards to assist identifications. All 32 possible isomers from 6,8-to 13,15-18:2 have been synthesised and the relative retention times determined on a 100 m CP-Sil 88 TM [14] (Table 1).…”

Section: Gas Chromatographic Analysismentioning

confidence: 99%

“…Oven temperature programme: 75°C for 2 min, then 5°C/min to 175°C, holding at 175°C for 33 min, then at 5°C/min to 225°C and finally holding at 225°C for 8 min. Adapted from Delmonte et al [14] Fig. 2 Comparison of partial gas chromatograms of the CLA methyl ester region from cheese total fatty acid methyl esters with flameionization detection (top) and the same region with high-resolution selected-ion recording (SIR) at m/z 294.2559 (molecular weight of CLA methyl ester) (bottom).…”

Section: Silver Ion High-performance Liquid Chromatographymentioning

confidence: 99%

“…Redrawn from Roach et al [8] with permission of the authors and Lipids. Some identities have been annotated using information from Delmonte et al [14] and Sehat et al [11] b the employment of two such columns connected in series to improve sample capacity and to provide the required peakto-peak resolutions, but up to six columns in series have been used for enhanced separations [12]. Typical isocratic flow rates of 1.0-2.0 ml/min and compositions of 0.1-1.0% acetonitrile in hexane in the mobile phase, maintained at a constant temperature of $23°C, are adjusted to maintain pump head pressures at 2,500 psi and to maintain total sample elution times of 35 min or less.…”

Section: Silver Ion High-performance Liquid Chromatographymentioning

confidence: 99%

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A Practical Guide to the Isolation, Analysis and Identification of Conjugated Linoleic Acid

Christie¹,

Dobson²,

Adlof

2007

Lipids

128

120

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Natural and synthetic conjugated linoleic acids (CLA) are reputed to have therapeutic properties that are specific to particular geometrical and positional isomers. Analysis of these has presented unique problems that have brought forward distinctive solutions, especially the use of gas chromatography-mass spectrometry and silver-ion high-performance liquid chromatography. In the analysis of CLA present at low levels in tissue samples, it is sometimes necessary to use concentration methods. In this review, the most useful and practical methods for the isolation and analysis of CLA isomers in tissues and in commercial CLA preparations are described.

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“…Although a total of 54 CLA isomers are possible (1), only about 20 CLA have been identified, including cis,cis; trans,trans; cis,trans; and trans,cis isomers of 7,9; 8,10; 9,11; 10,12; and 11,13 C18 diene acids (2). It is believed that the cis-9,trans-11 and trans-10,cis-12 isomers are the most bioactive CLA forms (3).…”

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confidence: 99%

Biocatalysis of linoleic acid to conjugated linoleic acid

Irmak

Dunford

Gilliland

et al. 2006

Lipids

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CLA refers to a group of geometrical and positional isomers of linoleic acid (LA) with conjugated double bonds. CLA has been reported to have diverse health benefits and biological properties. Traditional organic synthesis is highly capital-intensive and results in an isomeric mixture of CLA isomers. Biotechnology presents new alternatives to traditional lipid manufacturing methods. The objective of this study was to examine the effect of protein isolation procedures on linoleate isomerase (LAI) recovery from microbial cells and biocatalysis of LA to CLA. Protein isolation experiments were carried out using Lactobacillus acidophilus L1 and two strains of Lactobacillus reuteri (ATCC 23272 and ATCC 55739). Under the same assay conditions, ATCC 55739 had the highest LAI activity among the microbial cultures examined in this study. Efficiency of cell lysis methods, which included various combinations of lysozyme and mutanolysin treatments in combination with sonication and osmotic rupture of cells with liquid nitrogen, was very low. Although treatment of cell material with a detergent (octylthioglucoyranoside) freed a significant amount of LAI activity into the solution, it was not sufficient to recover all the LAI activity from the residual cells. Crude LAI preparations produced mainly the cis-9,trans-11 CLA isomer. Time and substrate/protein ratio had a significant effect on biocatalysis of LA to CLA. It appears that the mechanism and kinetics of enzymatic conversion of LA to CLA are quite complex and requires further research using pure LAI preparations.

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Synthesis, isolation, and GC analysis of all the 6,8‐to 13,15‐cis/trans conjugated linoleic acid isomers

Cited by 43 publications

References 16 publications

Trans-vaccenate is Δ13-desaturated by FADS3 in rodents

Trans-vaccenate is Δ13-desaturated by FADS3 in rodents

A Practical Guide to the Isolation, Analysis and Identification of Conjugated Linoleic Acid

Biocatalysis of linoleic acid to conjugated linoleic acid

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