Isomers of Conjugated Fatty Acids. I. Alkali-isomerized Linoleic Acid

Nichols, Peter L.; Herb, S. F.; Riemenschneider, R. W.

doi:10.1021/ja01145a084

Cited by 124 publications

(49 citation statements)

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“…In 1963, Riel (28) noted that summer milk fat had more conjugated dienoic acid than winter milk fat. More recently, conjugated linoleic acid (CLA) has been shown to inhibit chemically induced tumors (1, 10, 17), prevent atherosclerosis (24), and improve the protein-to-fat ratio in experimental animals (8).CLAs can be produced by alkaline isomerization, but there are as many as 16 isomers which are not fully characterized (26,29). Ruminant nutritionists have attempted to increase the naturally occurring CLA content of cow's milk via diet changes and alterations of ruminal fermentation (9).…”

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confidence: 99%

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Effect of Linoleic Acid Concentration on Conjugated Linoleic Acid Production by Butyrivibrio fibrisolvens A38

Kim¹,

Liu²,

Bond

et al. 2000

Appl Environ Microbiol

170

143

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Butyrivibrio fibrisolvens A38 inocula were inhibited by as little as 15 M linoleic acid (LA), but growing cultures tolerated 10-fold more LA before growth was inhibited. Growing cultures did not produce significant amounts of cis-9, trans-11 conjugated linoleic acid (CLA) until the LA concentration was high enough to inhibit biohydrogenation, growth was inhibited, and lysis was enhanced. Washed-cell suspensions that were incubated anaerobically with 350 M LA converted most of the LA to hydrogenated products, and little CLA was detected. When the washed-cell suspensions were incubated aerobically, biohydrogenation was inhibited, CLA production was at least twofold greater, and CLA persisted. The LA isomerase reaction was very rapid, but the LA isomerase did not recycle like a normal enzyme to catalyze more substrate. Cells that were preincubated with CLA lost their ability to produce more CLA from LA, and the CLA accumulation was directly proportional (r 2 ‫؍‬ 0.98) to the initial cell density. Growing cells were as sensitive to CLA as LA, the LA isomerase and reductases of biohydrogenation were linked, and free CLA was not released. Because growing cultures of B. fibrisolvens A38 did not produce significant amounts of CLA until the LA concentration was high, biohydrogenation was arrested, and the cell density had declined, the flow of CLA from the rumen may be due to LA-dependent bacterial inactivation, death, or lysis.In the 1930s, Booth et al. (3) noted that summer milk had a greater absorbance at 233 nm than milk produced in the winter, and later work indicated that rats fed summer milk grew better than those fed winter milk even if the fat content was similar (2). In 1963, Riel (28) noted that summer milk fat had more conjugated dienoic acid than winter milk fat. More recently, conjugated linoleic acid (CLA) has been shown to inhibit chemically induced tumors (1, 10, 17), prevent atherosclerosis (24), and improve the protein-to-fat ratio in experimental animals (8).CLAs can be produced by alkaline isomerization, but there are as many as 16 isomers which are not fully characterized (26,29). Ruminant nutritionists have attempted to increase the naturally occurring CLA content of cow's milk via diet changes and alterations of ruminal fermentation (9). Recent work indicated that polyunsaturated oil supplements could increase the CLA content of milk, but these diet-dependent increases were often small or transitory (9, 19).Many ruminal bacteria are inhibited by long-chain fatty acids (25), and gram-positive bacteria are more sensitive than gramnegative species (12). Polyunsaturated fatty acids are particularly toxic (21), but some ruminal bacteria are able to saturate the double bonds via a process known as biohydrogenation (27). In the 1960s, Kepler et al. (22) studied the biohydrogenation of Butyrivibrio fibrisolvens and demonstrated that linoleic acid (LA) was first converted to cis-9, trans-11 CLA. The reductase steps were inhibited by oxygen, but the LA isomerase could continue to produce cis-9, trans-11 CL...

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confidence: 99%

“…CLAs can be produced by alkaline isomerization, but there are as many as 16 isomers which are not fully characterized (26,29). Ruminant nutritionists have attempted to increase the naturally occurring CLA content of cow's milk via diet changes and alterations of ruminal fermentation (9).…”

mentioning

confidence: 99%

Effect of Linoleic Acid Concentration on Conjugated Linoleic Acid Production by Butyrivibrio fibrisolvens A38

Kim¹,

Liu²,

Bond

et al. 2000

Appl Environ Microbiol

170

143

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“…As many as 16 CLA isomers are known to be produced by alkaline isomerization of linoleic acid (LA) [27,33]. Of the CLA isomers, the cis-9, trans-11 (c9, t11) and the t10, c12 configurations are considered to be the most effective [31].…”

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confidence: 99%

Production of Conjugated Linoleic Acid by Intestinal Bacteria in Dogs and Cats.

Fukuda

Ninomiya

Asanuma

et al. 2002

The Journal of Veterinary Medical Science

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ABSTRACT. Production of conjugated linoleic acid (CLA) by the intestinal bacteria of dogs and cats was demonstrated by incubating their feces with linoleic acid (LA). CLA accumulated once, and then decreased with time. The numbers of LA-hydrogenating bacteria in the intestines appeared to decrease greatly with the ages of dogs and cats. As a major product of LA biohydrogenation, trans-vaccenic acid (t-VA) was identified. Most CLA and t-VA were readily solubilized by shaking the incubation mixture with bovine serum albumin, which strongly supports the presumption that CLA and t-VA are mostly formed on the outer surface of cell membrane, or excreted to the outer cell surface. This result suggests that CLA and t-VA can readily be absorbed through the large intestines. Triacylglycerol and phospholipid were shown to be hydrolyzed to free fatty acids by fecal bacteria, which is critical for biohydrogenation to occur, because esterified LA is not hydrogenated. However, since the ability of intestinal bacteria to produce CLA is probably low, it is desirable to augment CLA production.

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“…The rearrangement was shown to occur during auto oxidation of poyolefins (Bolland and Koch, 1945;Farmer et al, 1943) and treatment in the presence of nickel catalyst (Bailey, 1945;Radlove et al, 1946) or in the presnce of alkali at high temperatures ( Moore, 1939;Kass and Burr;1939). Nichols and his co-workers (Nichols et al, 1951) showed that the isomerisation of linoleic acid to CLAs could be achieved by alkali isomerisation at high temperatures. Furthermore, with available literature and analytical methodology, UV spectrometry, they were able to show that the predominant products in the alkali isomerisation were 9c11t and 10t12c CLAs.…”

Section: Introductionmentioning

confidence: 99%

“…With sophisticated analytical techniques, several reseachers have confirmed the fact that the main products formed in the alkali isomerization of 9c12c fatty acid were indeed 9c11t and 10t12c. Nichols and his co-workers (Nichols et al, 1951) have also used theoretical considerations and predicted the formation of conjugated linoleic acids from the cis/trans isomers of methylene interrupted 9,12 linoleic acids.…”

Section: Introductionmentioning

confidence: 99%

Evidence in the formation of conjugated linoleic acids from thermally induced 9t12t linoleic acid: a study by gas chromatography and infrared spectroscopy

Christy

2009

Chemistry and Physics of Lipids

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Thermally induced isomerisation leading to the formation of Conjugated Linoleic Acids (CLA) has been observed for the first time during the thermal treatment of 9t12t fatty acid triacylglycerol, and methyl ester. Fifteen microlitre portions of the triacylglycerol sample containing 9t12t fatty acid (trilinoelaidin) were placed in micro glass ampoules and sealed under nitrogen, then subjected to thermal treatment at 250 o C. The glass ampoules were removed at regular time intervals, cut open, and the contents were analysed by infrared spectroscopy using a single reflectance attenuated total internal reflectance crystal accessory. The samples were then subjected to derivatisation into their methyl esters. The methyl esters of the isomerised fatty acids were analysed by gas chromatography. The same procedure was repeated with methyl ester samples containing 9t12t fatty acid (methyl linoelaidate). Each sample was subjected to infrared measurements and gas chromatographic analysis after appropriate dilution in heptane.The results show that the thermally induced isomerisation of 9t12t fatty acids from both triacylglycerol molecules and methyl esters give identical CLA profiles as those found for the thermally induced isomerisation of 9c12c fatty acids. The infrared spectrometry provides additional evidence confirming the formation of CLA acids during thermal treatment. A mechanism for the formation of the CLAs from 9t12t fatty acid molecules is also formulated for the first time. This mechanism complements the pathways of formation of CLAs from 9c12c fatty acids during thermal treatment.Key words: Linoelaidin, Conjugated Linoleic Acids, Gas Chromatography, infrared spectroscopy, isomerisation. IntroductionConjugated Linoleic Acids (CLA) are natural components found in animal products such as meat and dairy products derived from ruminant animals. Conjugated Linoleic Acids have gained considerable attention in recent times because of their health benefits (Ip et al., 1991 and1994;Nicolosi et al., 1993;Shanta et al., 1992). This interest has been followed by an explosion of research reports on the benefits of CLAs in the areas of cancer, heart disease, diabetes and many other areas (Parodi, 1996; Belury and Van den Heuvel, 1997;Schrezenmeir and Jagia, 2000; Pariza, 2000;Scimeca and Miller, 2000;Kritchevsky, 2000;Thom et al., 2001;Voorrips et al., 2002;Belury, 2002;Larsen et al., 2003;Tricon et al., 2004; Lin Yang et al., 2004;Zulet et al., 2005;Wang et al., 2006;Bhattacharya et al, 2006;Kelley et al, 2007; Fite et al., Amarù and Field, 2009;Coakley et al, 2009). The results in these reports are based on the studies on animals and the beneficial effects on humans are yet to be proven.

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Isomers of Conjugated Fatty Acids. I. Alkali-isomerized Linoleic Acid

Cited by 124 publications

References 0 publications

Effect of Linoleic Acid Concentration on Conjugated Linoleic Acid Production by Butyrivibrio fibrisolvens A38

Effect of Linoleic Acid Concentration on Conjugated Linoleic Acid Production by Butyrivibrio fibrisolvens A38

Production of Conjugated Linoleic Acid by Intestinal Bacteria in Dogs and Cats.

Evidence in the formation of conjugated linoleic acids from thermally induced 9t12t linoleic acid: a study by gas chromatography and infrared spectroscopy

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