Isomers of linoleic acid. Infrared and ultraviolet properties of methyl esters

Jackson, John E.; Paschke, Raymond; Tolberg, W. E.; Boyd, H. M.; Wheeler, D. H.

doi:10.1007/bf02645651

Cited by 139 publications

(21 citation statements)

References 17 publications

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“…The bathochromic shift of the UV spectrum (from λ max = 231 nm of peaks #1 and #3 to λ max = 235 nm of peaks #2 and #4 in the present HPLC mobile phase) reflected the trans,trans and cis,trans isomers of conjugated fatty acid hydroperoxides (23,24). These spectral data supported the assignments that the hydroperoxide isomers were methyl 13-hydroperoxy-cis-9,trans-11-octadecadienoate (13-cis,trans), methyl 13-hydroperoxytrans-9,trans-11-octadecadienoate (13-trans,trans), methyl 9-hydroperoxy-trans-10,cis-12-octadecadienoate (9-trans,cis) and methyl 9-hydroperoxy-trans-10,trans-12-octadecadienoate (9-trans,trans), similar to those generated in the homogeneous solution.…”

Section: Changes In Pvmentioning

confidence: 99%

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion

Wang

Ohshima

Ushio

et al. 1999

Lipids

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The proportion of geometrical hydroperoxide isomers generated by aerobic oxidation of methyl linoleate (18:2 Me) in either aqueous emulsion consisting of Tris-HCl buffer (pH 7.4) or in a homogeneous dichloromethane solution was determined to understand the mechanism of lipid oxidation in different reaction systems. Four geometrical isomers were generated after oxidation of 18:2 Me in dichloromethane: methyl 13-hydroperoxy-cis-9, trans-11-octadecadienoate, methyl 13-hydroperoxy-trans-9,trans-11-octadecadienoate, methyl 9-hydroperoxy-trans-10,cis-12-octadecadienoate, and methyl 9-hydroperoxy-trans-10, trans-12-octadecadienoate in the ratios of 1:4:1:4, respectively. The ratios between each isomer did not change until the peroxide value (PV) increased to 58 meq/kg. Oxidation of 18:2 Me in aqueous emulsion yielded the same geometrical isomers of hydroperoxide. However, the ratios were different: 3:2:3:2 until the PV increased to 110 meq/kg. Predominant (60%) formation of trans,trans hydroperoxide isomers was obtained in the oxidation of a mixture of 18:2 Me and methyl laurate (12:0 Me). These results are interpreted to reflect the importance of the concentration of hydrogen atom-donating equivalents to the kinetic preference for different products. The high effective concentration of hydrogen donors in the oxidation of 18:2 Me in emulsions favored the formation of the less stable cis,trans isomers. The lower concentration of hydrogen donor in the dichloromethane solution effectively slowed hydrogen donation and led to the strong preference for the more stable trans,trans isomers. This interpretation was further tested by preparing emulsions of 18:2 Me and 12:0 Me to dilute concentration of hydrogen-donating species using the nonhydrogen-donating 12:0 Me. Consistent with the proposed hypothesis, the proportion of trans,trans isomers increased as a result of 12:0 Me addition.

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Section: Changes In Pvmentioning

confidence: 99%

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion

Wang

Ohshima

Ushio

et al. 1999

Lipids

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“…The absorbance of the isooctane layer was recorded at 233-nm wavelength by spectrophotometer against a blank (containing 20 l of the WCE, 1,580 l of 0.1 M potassium phosphate buffer, pH 7.0, and 300 l of 1,3-propanediol) in which LA was added after the stopper solution. The absorbance recorded at a 233-nm wavelength (which is the max of the diene bonds [18]) refers to the concentration of all the CLA isomers (CLAs' unspecific absorbance). However, considering that in the rumen up to 90% of the conjugated linoleic acids produced from linoleic acid are represented by RA (8), we assume that the LA-I assay can be applied primarily to the production of RA (47).…”

Section: Animals and Dietsmentioning

confidence: 99%

Bacterial and Protozoal Communities and Fatty Acid Profile in the Rumen of Sheep Fed a Diet Containing Added Tannins

Vasta

Yáñez-Ruíz

Mele³

et al. 2010

Appl Environ Microbiol

165

133

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This study evaluated the effects of tannins on ruminal biohydrogenation (BH) due to shifts in the ruminal microbial environment in sheep. Thirteen lambs (45 days of age) were assigned to two dietary treatments: seven lambs were fed a barley-based concentrate (control group) while the other six lambs received the same concentrate with supplemental quebracho tannins (9.57% of dry matter). At 122 days of age, the lambs were slaughtered, and the ruminal contents were subjected to fatty acid analysis and sampled to quantify populations of Butyrivibrio fibrisolvens, which converts C 18:2 c9-c12 (linoleic acid [LA]) to C 18:2 c9-t11 (rumenic acid [RA]) and then RA to C 18:1 t11 (vaccenic acid [VA]); we also sampled for Butyrivibrio proteoclasticus, which converts VA to C 18:0 (stearic acid [SA]). Tannins increased (P < 0.005) VA in the rumen compared to the tannin-free diet. The concentration of SA was not affected by tannins. The SA/VA ratio was lower (P < 0.005) for the tannin-fed lambs than for the controls, suggesting that the last step of the BH process was inhibited by tannins. The B. proteoclasticus population was lower (؊30.6%; P < 0.1), and B. fibrisolvens and protozoan populations were higher (؉107% and ؉56.1%, respectively; P < 0.05) in the rumen of lambs fed the tanninsupplemented diet than in controls. These results suggest that quebracho tannins altered BH by changing ruminal microbial populations.The fatty acid profile of the meat and milk of ruminants is strongly affected by diet (2, 15). When ingested, the dietary polyunsaturated fatty acids (PUFA) undergo a process known as biohydrogenation (BH) carried out by ruminal microorganisms (20). During the BH of C 18:2 (n-6) (linoleic acid [LA]) and C 18:3 (n-3) (linolenic acid [LNA]) a number of C 18:1 and C 18:2 isomers are formed (6). The last step in the BH process leads to the formation of C 18:0 (stearic acid [SA]). Among the intermediate products formed during this process, the isomer C 18:2 c9t11 (rumenic acid [RA]) is active in preventing cancer in mammals (17). Only a small amount of the RA found in meat and milk originates during BH. It is produced to a larger extent in muscle and mammary glands from the desaturation of Devillard et al. (11) have reported that protozoa do not have the capability of hydrogenating LA. The proportion of BH intermediates in the rumen can vary depending on changes in ruminal microbial populations (7, 51). Changes in ruminal fatty acid profiles are also reflected in intramuscular fatty acid composition (48,52).Tannins are phenolic compounds that are widespread in plants. When ingested by ruminants in large amounts, tannins can reduce the activity and the proliferation of ruminal microorganisms (34). Tannins from Lotus corniculatus (33) or from Acacia spp. (12) reduce the proliferation of B. proteoclasticus B316 T and B. proteoclasticus P18, respectively. Durmic et al. (12) reported that VA increased and SA decreased when extracts from Acacia iteaphylla, which contains condensed tannins (1), were incubated in vitro w...

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“…Identification of 13-Oxo-cis-9, trans-11 -tridecadienoic Acid (///) and 13-Oxo-trans-9,trans-1 1-tridecadienoic acid (I) UV (9). The presence of cis,trans unsaturation indicated that the cis-9,trans-11 double bond geometry of the parent hydroperoxide was retained.…”

Section: -Oxo-pda Reductasementioning

confidence: 99%

Metabolism of Fatty Acid Hydroperoxides by Chlorella pyrenoidosa

Vick¹,

Zimmerman²

1989

Plant Physiol.

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The green alga Chlorella pyrenoidosa was examined for its ability to metabolize 13-hydroperoxylinoleic and 13-hydroperoxylinolenic acids. The study showed that Chlorella extracts possessed hydroperoxide dehydrase and other enzymes of the jasmonic acid pathway. However, under normal laboratory conditions for culture growth, neither jasmonic acid nor metabolites of the jasmonic acid pathway were present in Chlorella. In vitro enzyme studies also revealed the presence of hydroperoxide lyase activity that cleaved 13-hydroperoxylinoleic or 13-hydroperoxylinolenic acid into two products, 13-oxo-cis-9,trans-11-tridecadienoic acid and pentane (from linoleic acid) or pentene (from linolenic acid). The lyase was heat-labile, insensitive to 50 millimolar KCN, and had an approximate molecular weight of 48,000 as estimated by gel filtration. Two other products, 13-hydroxy-cis-9,trans-11,cis-15-octadecatrienoic acid and 12,13-trans-epoxy-9-oxotrans-10,cis-15-octadecadienoic acid, were also observed. Because these compounds are also products of nonenzymic, Fe(ll)-catalyzed hydroperoxide decomposition reactions, their presence suggested that the observed lyase activity may occur via a homolytic decomposition mechanism.

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Isomers of linoleic acid. Infrared and ultraviolet properties of methyl esters

Cited by 139 publications

References 17 publications

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion

Proportion of geometrical hydroperoxide isomers generated by radical oxidation of methyl linoleate in homogeneous solution and in aqueous emulsion

Bacterial and Protozoal Communities and Fatty Acid Profile in the Rumen of Sheep Fed a Diet Containing Added Tannins

Metabolism of Fatty Acid Hydroperoxides by Chlorella pyrenoidosa

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