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1.
Kohei Yamamoto Akira Shibahara Akiko Sakuma Takao Nakayama Goro Kajimoto 《Lipids》1990,25(10):602-605
The pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis-monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such
as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The
main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic
(cis-9-hexadecenoic) acid andcis-vaccenic (cis-11-octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube
fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance
of n−5 monoenoic acid isomers. 相似文献
2.
G. Gowrikumar V. V. S. Mani T. Chandrasekhara Rao T. N. B. Kaimal G. Lakshminarayana 《Lipids》1981,16(7):558-559
The seeds ofDiplocyclos palmatus L. (Cucurbitaceae) contained 23% oil and 15% protein. The UV, IR,1H-NMR and13C-NMR spectrometry of the oil, and oxidation, reduction and gas liquid chromatography (GLC) of the methyl ester of conjugated
fatty acid isolated by preparative thin layer chromatography (TLC) showed the presence of punicic (octadeca-cis-9,trans-11,cis-13-trienoic) acid. The fatty acid composition (wt %), as determined by GLC, is: punicic, 38.2; 18∶2, 43.9; 16∶0, 8.1; 18∶0,
4.9 and 18∶1, 4.9. 相似文献
3.
K. D. Carlson A. Chaudhry R. E. Peterson M. O. Bagby 《Journal of the American Oil Chemists' Society》1990,67(8):495-498
To conduct product development research onLesquerella seed oils, we explored methods to obtain >100 g quantities of lesquerolic (14-hydroxy-cis-11-eicosenoic) acid. Preliminary experiments with open-column silica gel chromatography showed thatL. fendleri oil could be separated into 3 triglyceride (TG) fractions. The first (10%) contained nonhydroxy 16-(13%) and 18-carbon acids
(65% 18∶1,2,3). The second fraction (15%) contained monolesquerolins (39% lesquerolic acid). The major TG fraction (73%) was
mainly dilesquerolins (66% lesquerolic acid) showing that a hydroxy acid-enriched TG oil was obtainable by this procedure.
Silica gel chromatography easily separatedL. fendleri fatty acid methyl esters (FAME) into a hydroxy-free ester fraction (40–44%) consisting largely of 18∶1 (39%), 18∶2 (19%)
and 18∶3 (31%), and a hydroxy ester fraction (56–60%) that was largely methyl lesquerolate (94%) with small amounts of auricolate
(5%) (14-hydroxy-cis-11,cis-17-eicosadienoate) and traces of 18-carbon hydroxy esters. This process for isolating the hydroxy FAME ofLesquerella oil was scaled up 15-to 100-fold with a preparative high performance liquid chromatograph. Thirty-gram samples ofL. gordonii FAME were dissolved in eluting solvent, pumped onto the high performance liquid chromatography (HPLC) silica column and eluted
with 97∶3 hexane/ethyl acetate. In an 8-hr period, up to 200 g of methyl lesquerolate could be obtained with a purity >98%,
the only contaminants being methyl auricolate and methyl ricinoleate.
Presented at the AOCS meeting in Phoenix, AZ, May 1988.
The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of
Agriculture over other firms or similar products not mentioned. 相似文献
4.
Yoshie Kitayama Masahiro Muraoka Megumi Takahashi Tatsuya Kodama Hirofumi Itoh Eriko Takahashi Mutsuo Okamura 《Journal of the American Oil Chemists' Society》1996,73(10):1311-1316
The catalytic activity and selectivity for hydrogenation of linoleic acid were studied on Ni, Cu, and Pd catalysts. A detailed
analysis of the reaction product was performed by a gas-liquid chromatograph, equipped with a capillary column, and Fourier
transform-infrared spectroscopy. Geometrical and positional isomerization of linoleic acid occurred during hydrogenation,
and many kinds of linoleic acid isomers (trans-9,trans-12; trans-8,cis-12 orcis-9,trans-13; cis-9,trans-12; trans-9,cis-12 andcis-9,cis-12 18∶2) were contained in the reaction products. The monoenoic acids in the partial hydrogenation products contained eight
kinds of isomers and showed different isomer distributions on Ni, Cu, and Pd catalysts, respectively. The positional isomers
of monoenoic acid were produced by double-bond migration during hydrogenation. On Ni and Pd catalysts, the yield ofcis-12 andtrans-12 monoenoic acids was larger than that ofcis-9 andtrans-9 monoenoic acids. On the contrary, the yield ofcis-9 andtrans-9 monoenoic acids was larger than that ofcis-12 andtrans-12 monoenoic acids on Cu catalyst. From these results, it is concluded that the double bond closer to the methyl group (Δ12)
and that to the carboxyl group (Δ9) show different reactivity for hydrogenation on Ni, Cu, and Pd catalysts. Monoenoic acid
formation was more selective on Cu catalyst than on Ni and Pd catalysts. 相似文献
5.
A new conjugated linoleic acid isomer, 7 trans, 9 cis-octadecadienoic acid, in cow milk, cheese, beef and human milk and adipose tissue 总被引:1,自引:0,他引:1
Martin P. Yurawecz John A. G. Roach Najibullah Sehat Magdi M. Mossoba John K. G. Kramer Jan Fritsche Hans Steinhart Youh Ku 《Lipids》1998,33(8):803-809
The identity of a previously unrecognized conjugated linoleic acid (CLA) isomer, 7 trans, 9 cis-octadecadienoic acid (18∶2) was confirmed in milk, cheese, beef, human milk, and human adipose tissue. The 7 trans, 9 cis-18∶2 isomer was resolved chromatographically as the methyl ester by silver ion-high-performance liquid chromatography (Ag+-HPLC); it eluted after the major 9 cis, 11 trans-18∶2 isomer (rumenic acid) in the natural products analyzed. In the biological matrices in-vestigated by Ag+-HPLC, the 7 trans, 9 cis-18∶2 peak was generally due to the most abundant minor CLA isomer, ranging in concentration from 3 to 16% of total CLA. By
gas chromatography (GC) with long polar capillary columns, the methyl ester of 7 trans, 9 cis-18∶2 was shown to elute near the leading edge of the major 9 cis, 11 trans-18∶2 peak, while the 4,4-dimethyloxazoline (DMOX) derivative permitted partial resolution of these two CLA isomers. The DMOX
derivative of this new CLA isomer was analyzed by gas chromatography-electron ionization mass spectrometry (GC-EIMS). The
double bond positions were at Δ7 and Δ9 as indicated by the characteristic mass spectral fragment ions at m/z 168, 180, 194, and 206, and their allylic cleavages at m/z 154 and 234. The cis/trans double-bond configuration was established by GC-direct deposition-Fourier transform infrared as evidenced from the doublet
at 988 and 949 cm−1 and absorptions at 3020 and 3002 cm−1. The 7 trans, 9 cis-18∶2 configuration was established by GC-EIMS for the DMOX derivative of the natural products examined, and by comparison
to a similar product obtained from treatment of a mixture of methyl 8-hydroxy-and 11-hydroxyoctadec-9 cis enoates with BF3, in methanol.
Contribution number S010 from the Food Research Center, Guelph, Ontario, Canada. 相似文献
6.
To determine which structural characteristics of membrane phospholipids influence adenylate cyclase activity, we measured
basal and sodium fluoride- or forskolin-stimulated activity in a murine fibroblast cell line,i.e., Balb/c3T3 cells grown in media supplemented with fetal calf serum (FCS), lipid-depleted FCS (LD-FCS) or LD-FCS complexed
with different phosphatidylcholine (PC) molecular species. Cells grown in the presence of LD-FCS showed a substantial decrease
in their basal and NaF-stimulated adenylate cyclase activities; however, their forskolin-stimulated activity was not altered,
suggesting that the enzyme's catalytic site is not affected by changes in membrane lipids. Media supplemented with different
LD-FCS/PC complexes were shown to prevent the LD-FCS-mediated reduction of basal and NaF-stimulated adenylate cyclase activity
to different extents. Addition ofcis-9-16∶1/cis-9-16∶1,cis-9-18∶1/cis-9-18∶1 orcis-9-18∶1/cis-9,12-18∶2sn-glycerophosphocholine (GPC) completely restored adenylate cyclase activity, whilecis-11-18∶1/cis-11-18∶1 GPC was not effective and only a partial recovery was observed with 16∶0/16∶0, 16∶0/cis-9-18∶1 andtrans-9-18∶1 GPC. Considering the structural features of these seven PC molecular species, the findings suggest that an optimal
lipid environment is conferred to the enzyme by the presence of thecis double bonds, each located in Δ9 position of the PC acyl chains. The limited effect ofcis-9-16∶1/cis-9-18∶1 GPC andcis-9-18∶1/cis-9-16∶1 GPC suggests that an equal length of the terminal hydrocarbon chains extending bevond the Δ9 double bonds is also
important. Moreover, complete restoration of adenylate cyclase activity in cells exposed to 16∶0/cis-9,12-18∶2 GPC suggests that twocis-9,12 double bonds located on the same chain are as effective as twocis-9 double bonds each located on two different chains of PC. As the four double bonds of 16∶0/cis-5,8,11,14-20∶4 GPC had no effect, a mere increase in the number of double bonds seems insufficient to build an optimal lipid
microenvironment for the enzyme. 相似文献
7.
Preparation, separation, and confirmation of the eight geometrical cis/trans conjugated linoleic acid isomers 8,10-through 11,13–18∶2 总被引:1,自引:0,他引:1
Klaus Eulitz Martin P. Yurawecz Najibullah Sehat Jan Fritsche John A. G. Roach Magdi M. Mossoba John K. G. Kramer Richard O. Adlof Yuoh Ku 《Lipids》1999,34(8):873-877
Conjugated linoleic acid (CLA) mixtures were isomerized with p-toluenesulfinic acid or I2 catalyst. The resultant mixtures of the eight cis/trans geometric isomers of 8,10-, 9,11-, 10,12-, and 11,13-octadecadienoic (18∶2) acid methyl esters were separated by silver ion-high-performance
liquid chromatography (Ag+-HPLC) and gas chromatography (GC). Ag+-HPLC allowed the separation of all positional CLA isomers and geometric cis/trans CLA isomers except 10,12–18∶2. However, one of the 8,10 isomers (8cis, 10trans-18∶2) coeluted with the 9trans,11cis18∶2 isomer. There were differences in the elution order of the pairs of geometric CLA isomers resolved by Ag+-HPLC. For the 8,10 and 9,11 CLA isomers, cis,trans eluted before trans,cis, whereas the opposite elution pattern was observed for the 11,13–18∶2 geometric isomers (trans,cis before cis,trans). All eight cis/trans CLA isomers were separated by GC on long polar capillary columns only when their relative concentrations were about equal.
Large differences in the relative concentration of the CLA isomers found in natural products obscured the resolution and identification
of a number of minor CLA isomers. In such cases, GC-mass spectrometry of the dimethyloxazoline derivatives was used to identify
and confirm coeluting CLA isomers. For the same positional isomer, the cis,trans consistently eluted before the trans,cis CLA isomers by GC. High resolution mass spectrometry (MS) selected ion recording (SIR) of the molecular ions of the 18∶1
18∶2, and 18∶3 fatty acid methyl esters served as an independent and highly sensitive method to confirm CLA methyl ester peak
assignments in GC chromatograms obtained from food samples by flame-ionization detection. The high-resolution MS data were
used to correct for the nonselectivity of the flame-ionization detector. 相似文献
8.
Improved separation of conjugated fatty acid methyl esters by silver ion-high-performance liquid chromatography 总被引:4,自引:7,他引:4
Najibullah Sehat Rainer Rickert Magdi M. Mossoba John K. G. Kramer Martin P. Yurawecz John A. G. Roach Richard O. Adlof Kim M. Morehouse Jan Fritsche Klaus D. Eulitz Hans Steinhart Yuoh Ku 《Lipids》1999,34(4):407-413
Operating from one to six silver ion-high-performance liquid chromatography (Ag+-HPLC) columns in series progressively improved the resolution of the methyl esters of conjugated linoleic acid (CLA) isomeric
mixtures from natural and commercial products. In natural products, the 8 trans, 10 cis-octadecadienoic (18∶2) acid was resolved from the more abundant 7 trans, 9 cis-18∶2, and the 10 trans, 12 cis-18∶2 was separated from the major 9 cis, 11 trans-18∶2 peak. In addition, both 11 trans, 13 cis-18∶2 and 11 cis, 13 trans-18∶2 isomers were found in natural products and were separated; the presence of the latter, 11 cis, 13 trans-18∶2, was established in commercial CLA preparations. Three Ag+-HPLC columns in series appeared to be the best compromise to obtain satisfactory resolution of most CLA isomers found in
natural products. A single Ag+-HPLC column in series with one of several normal-phase columns did not improve the resolution of CLA isomers as compared
to that of the former alone. The 20∶2 conjugated fatty acid isomers 11 cis, 13 trans-20∶2 and 12 trans, 14 cis-20∶2, which were synthesized by alkali isomerization from 11 cis, 14 cis-20∶2, eluted in the same region of the Ag+-HPLC chromatogram just before the corresponding geometric CLA isomers. Therefore, CLA isomers will require isolation based
on chain length prior to Ag+-HPLC separation. The positions of conjugated double bonds in 20∶2 and 18∶2 isomers were established by gas chromatography-electron
ionization mass spectrometry as their 4,4-dimethyloxazoline derivatives. The double-bond geometry was determined by gas chromatography-direct
deposition-Fourier transform infrared spectroscopy and by the Ag+-HPLC relative elution order. 相似文献
9.
Phospholipid content and fatty acid composition of human heart were determined on 36 biopsy specimens collected during open
heart surgery. The main phospholipid classes, phosphatidylcholine (PC), phosphatidylethanolamine (PE), diphosphatidylglycerol
(DPG), and sphingomyelin (SPH) were separated by HPLC, quantified, and converted to fatty acid methyl esters which were chromatographed
on capillary GLC columns. Sex and age (mainly 40–70) of patients had no significant influence on the relative distribution
of phospholipid classes and only a slight effect on fatty acid composition. Incorporation oftrans 18∶1 in phospholipid classes was low.cis andtrans octadecenoic isomers seemed to be selectively incorporated, the Δ9 and Δ11cis ortrans isomers being predominant. Human and rat data were compared, and some species differences were noticed. In human PC, palmitic
acid is higher and stearic acid much lower than in rat PC. Saturated dimethyl acetals (16∶0 and 18∶0) in PC and PE were greater
for humans. Incorporation of 20∶4 n−6 in human PE is higher than in rat PE. 相似文献
10.
Lipase-catalyzed fractionation of conjugated linoleic acid isomers 总被引:14,自引:0,他引:14
Haas MJ Kramer JK McNeill G Scott K Foglia TA Sehat N Fritsche J Mossoba MM Yurawecz MP 《Lipids》1999,34(9):979-987
The abilities of lipases produced by the fungus Geotrichum candidum to selectively fractionate mixtures of conjugated linoleic acid (CLA) isomers during esterification of mixed CLA free fatty
acids and during hydrolysis of mixed CLA methyl esters were examined. The enzymes were highly selective for cis-9,trans-11–18∶2. A commercial CLA methyl ester preparation, containing at least 12 species representing four positional CLA isomers,
was incubated in aqueous solution with either a commercial G. candidum lipase preparation (Amano GC-4) or lipase produced from a cloned high-selectivity G. candidum lipase B gene. In both instances selective hydrolysis of the cis-9,trans-11–18∶2 methyl ester occurred, with negligible hydrolysis of other CLA isomers. The content of cis-9,trans-11–18∶2 in the resulting free fatty acid fraction was between 94 (lipase B reaction) and 77% (GC-4 reaction). The commercial
CLA mixture contained only trace amounts of trans-9,cis-11–18∶2, and there was no evidence that this isomer was hydrolyzed by the enzyme. Analogous results were obtained with these
enzymes in the esterification in organic solvent of a commercial preparation of CLA free fatty acids containing at least 12
CLA isomers. In this case, G. candidum lipase B generated a methyl ester fraction that contained >98% cis-9,trans-11–18∶2. Geotrichum candidum lipases B and GC-4 also demonstrated high selectivity in the esterification of CLA with ethanol, generating ethyl ester fractions
containing 96 and 80%, respectively, of the cis-9,trans-11 isomer. In a second set of experiments, CLA synthesized from pure linoleic acid, composed essentially of two isomers,
cis-9,trans-11 and trans-10,cis-12, was utilized. This was subjected to esterification with octanol in an aqueous reaction system using Amano GC-4 lipase
as catalyst. The resulting ester fraction contained up to 97% of the cis-9,trans-11 isomer. After adjustment of the reaction conditions, a concentration of 85% trans-10,cis-12–18∶2 could be obtained in the unreacted free fatty acid fraction. These lipase-catalyzed reactions provide a means for
the preparative-scale production of high-purity cis-9,trans-11–18∶2, and a corresponding CLA fraction depleted of this isomer. 相似文献
11.
Thetrans 16∶1, 18∶1 and 18∶2 fatty acid composition of various human organ lipids was studied to determine if isomers accumulated
in specific tissues. “Trans” isomers are defined as those fatty acids containing one or moretrans double bonds. Adipose, kidney, brain, heart and liver tissue lipids were analyzed. Gas chromatography with a 100-SP2560 capillary
column was used to characterize the various positional and/or geometrical isomers. The distribution ofrans 16∶1 and 18∶1 isomers ranged from 0.3% in the brain to 4.0% in adipose tissue, whiletrans 18∶2 isomers ranged from 0.0% in the brain to 0.4% in adipose tissue. Notrans 18∶3 isomers were detected. Positional isomer ratios forcis 16∶1 (Δ9 vs Δ7) andcis 18∶1 (Δ11 vs Δ9) were also determined. Since these ratios are reproducible from one individual to the next, they might be
useful for diagnosis of human metabolic disorders. 相似文献
12.
Robert L. Wolff 《Journal of the American Oil Chemists' Society》1994,71(8):907-909
Analysis of alpha-linolenic acid geometrical isomers in deodorized or heated oils by capillary gas-liquid chromatography (GLC)
on polar cyanoalkyl polysiloxane stationary phases requires some care to avoid interferences with other fatty acids. Depending
on the temperature of the column, thecis-11 20∶1 acid may elute before, with or after thecis-9,cis-12,cis-15 18∶3 acid during GLC. In some instances [temperature higher than 180°C with a CP Sil 88 column (Chrompack, Middelburg,
The Netherlands)], the 20∶1 acid coelutes with thetrans-9,cis-12,cis-15 18∶3 acid, leading to abnormally high levels of this last isomer. Consequently, the degree of isomerization of alpha-linolenic
acid will be over-estimated under such conditions. It is recommended that the behavior ofcis-11 20∶1 acid relative to temperature be checked carefully prior to the determination of alpha-linolenic acid geometrical
isomers by GLC. Temperatures lower than 160°C seem appropriate to separate all of these components from each other and fromcis-11 20∶1 acid in a 50 m×0.25 mm i.d. CP Sil 88 capillary column. 相似文献
13.
Robert L. Wolff 《Lipids》1995,30(10):893-898
When rats were fed elaidic (trans-9 18∶1) acid at a high load in diets that were otherwise marginally or almost completely deficient in linoleic (cis-9,cis-12 18∶2) acid, elaidic acid was desaturated tocis-5,trans-9 18∶2 acid. This polymethylene-interrupted acid was then incorporated into most phospholipids from rat mitochondria, cardiolipin
being an exception. Its level of esterification in phospholipids followed the increasing order: phosphatidylethanolamine <phosphatidylcholine
< phosphatidylinositol (PI). The content ofci-5,trans-9 18∶2 acid decreased in organs in the order liver > kidney > heart. The levels ofcis-5,trans-9 18∶2 acid increased in mitochondria phospholipids as the level of linoleic acid was lowered in the diet. In liver mitochondria
PI, it reached 16% of total fatty acids. After hydrolysis of liver mitochondria PI withNaja naja phospholipase A2, we observed that elaidic acid was essentially esterified to position 1 at the expense of saturated acids, whereascis-5,trans-9 18∶2 acid was exclusively esterified to position 2, along with 20∶3n−9 and 20∶4n−6 acids. As a consequence, the sums of
saturated andtrans-9 18∶1 acids on the one hand, and of 20∶3n−9, 20∶4n−6, andcis-5,trans-9 18⩺2 acids on the other hand, remained fairly constant in liver mitochondria PI (ca. 55 and 30%, respectively). Becausetrans-9 18∶1 andcis-5,trans-9 18∶2 acids differ only by thecis-5 ethylenic bond, which is also present in 20∶3n−9 and 20∶4n−6 acids, this distribution pattern indicates that thecis-5 double bond, rather than any other ethylenic bond, may be of major structural importance for channeling fatty acids to
position 2 of PI. 相似文献
14.
Robert L. Wolff Jean-Louis Sébédio 《Journal of the American Oil Chemists' Society》1994,71(2):117-126
Heating of borage oil, either under vacuum as a model or during steam-vacuum deodorization, produces artifacts that are geometrical
isomers of γ-linolenic acid (cis-6,cis-9,cis-12 18∶3 acid). In a first approach, we have studied the behavior of these fatty acids in the form of either methyl or isopropyl
esters on two capillary columns (CP-Sil 88 and DB-Wax). From this study, it appears that the DB-Wax capillary column is the
best suited analytical tool to study in some detail γ-linolenic acid geometrical isomers. In a second approach, the structure
of these isomers was formally established by combining several analytical techniques: Argentation thin-layer chromatography,
comparison of the equivalent chainlengths with those of isomers present in NO2-isomerized borage oil on two different capillary columns, partial hydrazine reduction, oxidative ozonolysis, gas chromatography
coupled with mass spectrometry and gas chromatography coupled with Fourier transform infrared spectroscopy. The two main isomers
that accumulate upon heat treatments are thetrans-6,cis-9,cis-12 andcis-6,cis-9,trans-12 18∶3 acids with minor amounts ofcis-6,trans-9,cis-12 18∶3 acid. One di-trans isomer, supposed to be thetrans-6,cis-9,trans-12 18∶3 acid, is present in low although noticeable amounts in some of the heated oils. The content of these artificial fatty
acids increases with increasing temperatures and duration of heating. The degree of isomerization (DI) of γ-linolenic acid
is less than 1% when the oil is deodorized at 200°C for 2 h. Heating at 260°C for 5 h increases the DI up to 74%. Isomerization
of γ-linolenic acid resembles that of α-linolenic (cis-9,cis-12,cis-15 18∶3) acid in several aspects: The same kinds and numbers of isomers are formed, and similar degrees of isomerization
are reached when the octadecatrienoic acids are heated under identical conditions. It seems that the reactivity of a double-bondvis-à-vis cis-trans isomerization is linked to its relative position, central or external, and not to its absolute position (Δ6, 9, 12 or 15). 相似文献
15.
The ciliate,Tetrahymena, was provided a supplement of the fatty acid [1-14C] 18∶2Δ6,9. After a period of growth the cells were claimed, the lipids extracted, the polar lipids recovered and the mild
alkali-labile fatty acid methyl esters generated. The fatty acids were resolved by high pressure liquid chromatography (HPLC),
the 18∶3Δ6,9,12 (γ-linolenic acid) was recovered and its identity verified by high pressure liquid chromatography (HPLC),
gas liquid chromatography (GLC), hydrogenation and oxidation. Fifty-three percent of the cell-associated label was found in
γ-linolenic acid; thus, a Δ12 fatty acid desaturase converts the 6,9 octadecadienoic acid to the 6,9,12 derivative. No carboxyl
or methyl terminus restriction appears on Δ9 monoenoic or dienoic fatty acid desaturation in this cell as is found in higher
plants and animals. 相似文献
16.
Milk samples were collected from 11 mothers who were at least 4 weeks postpartum. The amounts of fat and the fatty acid compositions
of cholesteryl esters (CE) and triacylglycerols (TG) in the milk were determined. The mean concentration of total milk lipid
was 3.01 gm/100 ml of milk±.42 SD. The major fatty acids esterified with CE and TG were 16∶0,cis 18∶1 and 18∶2. The patterns were similar except for a greater proportion ofcis 18∶1 in the CE. The majortrans fatty acid detected was the 18∶1 isomer which accounted for 4.48% of the TG fatty acids and 2.96% of the CE fatty acids.
Scientific Contribution No. 821, Storrs Agricultural Experiment Station, University of Connecticu, Storrs, CT. 06268 相似文献
17.
E. A. Emken H. J. Dutton W. K. Rohwedder Henry Rakoff R. O. Adlof R. M. Gulley J. J. Canary 《Lipids》1980,15(10):864-871
Triglycerides containingcis- andtrans-12-octadecenoic acid (12c-18∶1 and 12t-18∶1) andcis-9-octadecenoic acid (9c-18∶1) labeled with deuterium were fed to 2 young adult male subjects. These fatty isomers each contained a different number
of deuterium labels, which allowed mass spectrometric analysis to distinguish among them after they were fed as a mixture.
This approach results in a direct comparison of the absorption and distribution of these 3 monoenoic acids into blood plasma
and lipoprotein lipids. Plasma lipid data indicated that all phospholipid fractions selectively incorporate 12c-18∶1 and 12t-18∶1 in preference to 9c-18∶1. Discrimination against 12c-18∶1 and 12t-18∶1 compared to 9c-18∶1 was found in the plasma neutral lipids, with a strong discrimination against 12t-18∶1 incorporation into the cholesteryl ester fraction. Considerable reduction in the percentage of linoleic and arachidonic
acid was observed when 12–18∶1 isomers were incorporated in plasma triglyceride, phosphatidylcholine and sphingomyelin samples.
Chylomicron lipid analyses indicated that all isomers were well absorbed. Variation was observed in the relative distribution
of 12c-18∶1, 12t-18∶1 and 9c-18∶1 between the very low density, low density and high density lipoprotein lipid classes. No desaturation of 12c-18∶1 to linoleic acid was detected. 相似文献
18.
Conjugated linoleic acid (CLA) is a collective term that describes different isomers of linoleic acid with conjugated double
bonds. Although the main dietary isomer is 9cis,11trans-18∶2, which is present in dairy products and ruminant fat, the biological effects of CLA generally have been studied using
mixtures in which the 9cis,11trans- and the 10trans,12cis-18∶2 were present at similar levels. In the present work, we have studied the impact of each isomer (9cis,11trans- and 10trans,12cis-18∶2) given separately in the diet of rats for 6 wk. The 10trans,12cis-18∶2 decreased the triacylglycerol content of the liver (−32%) and increased the 18∶0 content at the expense of 18∶1n−9,
suggesting an alteration of the Δ9 desaturase activity, as was already demonstrated in vitro. This was not observed when the 9cis,11trans-18∶2 was given in the diet. Moreover, the 10trans,12cis-18∶2 induced an increase in the C22 polyunsaturated fatty acids in the liver lipids. The 10trans,12cis-18∶2 was mainly metabolized into conjugated 16∶2 and 18∶3, which have been identified. The 9cis,11trans isomer was preferentially metabolized into a conjugated 20∶3 isomer. Thus, the 9cis,11trans- and the 10trans,12cis-CLA isomers are metabolized differently and have distinct effects on the metabolism of polyunsaturated fatty acids in rat
liver while altering liver triglyceride levels differentially. 相似文献
19.
Robert L. Wolff Laurent G. Deluc Anne M. Marpeau 《Journal of the American Oil Chemists' Society》1996,73(6):765-771
The seed oils from twenty-five Conifer species (from four families—Pinaceae, Cupressaceae, Taxodiaceae, and Taxaceae) have
been analyzed, and their fatty acid compositions were established by capillary gas-liquid chromatography on two columns with
different polarities. The oil content of the seeds varied from less than 1% up to 50%. Conifer seed oils were characterized
by the presence of several Δ5-unsaturated polymethylene-interrupted polyunsaturated fatty acids (Δ5-acids) with either 18
(cis-5,cis-9, 18∶2,cis-5,cis-9,cis-12 18∶3, andcis-5,cis-9,cis-12,cis-15 18∶4 acids) or 20 carbon atoms (cis-5,cis-11 20∶2,cis-5,cis-11,cis-14, 20∶3, andcis-5,cis-11,cis-14,cis-17 20∶4 acids). Pinaceae seed oils contained 17–31% of Δ5-acids, mainly with 18 carbon atoms. The 20-carbon acids present
were structurally derived from 20∶1n-9 and 20∶2n-6 acids. Pinaceae seed oils were practically devoid of 18∶3n-3 acid and did
not contain either Δ5-18∶4 or Δ5-20∶4 acids. Several Pinaceae seeds had a Δ5-acid content higher than 50 mg/g of seed. The
only Taxaceae seed oil studied (Taxus baccata) had a fatty acid composition related to those of Pinaceae seed oils. Cupressaceae seed oils differed from Pinaceae seed
oils by the absence of Δ5-acids with 18 carbon atoms and high concentrations in 18∶3n-3 acid and in Δ5-acids with 20 carbon
atoms (Δ5-20∶3 and Δ5-20∶4 acids). Δ5-18∶4 Acid was present in minute amounts. The highest level of Δ5-20∶4 acid was found
inJuniperus communis seed oil, but the best source of Δ5-acids among Cupressaceae wasThuja occidentalis. Taxodiaceae seed oils had more heterogeneous fatty acid compositions, but the distribution of Δ5-acids resembled that found
in Cupressaceae seed oils. Except forSciadopytis verticillata, other Taxodiaceae species are not interesting sources of Δ5-acids. The distribution profile of Δ5-acids among different
Conifer families appeared to be linked to the occurrence of 18∶3n-3 acid in the seed oils. 相似文献
20.
Dibutyroyl derivatives of monoacylglycerols (DBMAG) from conifer seed oil triacylglycerols (TAG) were prepared by partial
deacylation of TAG with ethylmagnesium bromide followed by diesterification with n-butyryl chloride. The resulting mixtures were analyzed by gas-liquid chromatography (GCL) with 65% phenylmethyl silicon open
tubular fused-silica capillary column operated under optimal conditions and separated according to both their fatty acid structures
and their regiospecific distribution. Seed oils of 18 species from 5 conifer families (Pinaceae, Taxaceae, Cupressaceae, Cephalotaxaceae,
and Podocarpaceae) were analyzed. The chromatograms showed a satisfactory resolution of DBMAG containing palmitic (16∶0) stearic
(18∶0), taxoleic (cis-5, cis-9 18∶2), oleic (cis-9 18∶1), cis-vaccenic (cis-11 18∶1), pinolenic (cis-5, cis-9, cis-12 18∶3), linoleic (cis-9, cis-12 18∶2), α-linolenic (cis-9 cis-12, cis-15 18∶3), and an almost baseline resolution of DBMAG containing gondoic (cis-11 20∶1), cis-5, cis-11 20∶2, sciadonic (cis-5, cis-11, cis-14 20∶3), dihomolinoleic (cis-11 cis-14 20∶2), juniperonic (cis-5, cis-11, cis-14, cis-17 20∶4), and dihomo-α-linolenic (cis-11, cis-14, cis-17 20∶3) acids. We have observed that results for Pinus pinaster and P. koraiensis seed oils obtained with this new simple method compared favorably with literature data established with other usual regiospecific
analytical techniques. Δ5-Olefinic acids are esterified mainly at the external positions of the glycerol backbone in all cases,
in agreement with data obtained by other methodologies allowing validation of the GLC regiospecific method. To date, 45 gymnosperm
species (mostly Coniferophytes) from 21 genera belonging to 9 families have been analyzed, all of them showing a definite
enrichment of Δ5-olefinic acids in the external positions of TAG. These fatty acids (FA), with one exception only, represent
between-2 and 8% of FA esterified to the internal positions. For some species, i.e., P. koraiensis and P. pinaster, this asymmetrical distribution was established by at least three analytical procedures and confirmed by stereospecific analysis
of their seed TAG. 相似文献