Linked Life Data

17954767

Source:http://linkedlifedata.com/resource/pubmed/id/17954767

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2007-10-23
pubmed:abstractText
Conjugated linolenic acids (CLnA) are octadecatrienoic fatty acid isomers with at least 2 conjugated double bonds. Various CLnA isomers occur naturally, and some isomers could be formed by ruminants from dietary alpha-linolenic acid. Ruminant biohydrogenation of polyunsaturated fatty acids gives rise to the formation of numerous metabolites having conjugated or nonconjugated structures. The objectives of this study were to identify and characterize CLnA isomers in milk fat and muscle lipid extracts from cattle fed a high-forage diet. The analysis of total fatty acid methyl esters revealed levels of total CLnA of 0.39% in a single milk lipid extract and 0.34% in a single muscle lipid extract. Fatty acid methyl esters were fractionated by argentation thin-layer chromatography. A fraction containing dienoic fatty acids as well as CLnA isomers was isolated and analyzed. The double bond positions of CLnA isomers (cis-9, trans-11, cis-15 and cis-9, trans-13, cis-15 18:3) were confirmed by mass spectrometry of their 4,4-dimethyloxazoline derivatives. Mass spectra of the cis-9, trans-13, cis-15 18:3 isomer was characterized by an intense ion at m/z 236 attributable to the formation of 2 stabilized allylic radical fragments, whereas this intense ion corresponding to the stabilized radical fragments was located at m/z 262 for the cis-9, trans-11, cis-15 18:3 isomer. The gap of 12 amu between m/z 250 and 262 confirmed the occurrence of a double bond in position delta13. Configuration of the double bonds of standards having similar mass spectra and gas-liquid chromatographic retention times was confirmed by 1H nuclear magnetic resonance. We also showed that both CLnA isomers were found in the muscle lipid extract, whereas only the cis-9, trans-11, cis-15 18:3 isomer was identified in the milk lipid extract. This study appears to be the first to identify 2 CLnA isomers in bovine muscle lipid extract.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1525-3198
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
90
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5269-75
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Conjugated alpha-linolenic acid isomers in bovine milk and muscle.
pubmed:affiliation
Department of Food Science and Nutrition, Institut des Nutraceutiques et des Aliments Fonctionnels/Centre de Recherche en Sciences et Technologie du Lait, Université Laval, Québec, Canada G1K 7P4. melanie.plourde2@usherbrooke.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't