cis-Vaccenic acid in mango pulp lipids

A peak corresponding to a methyl octadecenoate other than oleate has been detected on the capillary gas chromatogram of the methyl esters of mango pulp fatty acids. This octadecenoate was isolated by silica gel and argentation column chromatography, high performance liquid chromatography and argentation thin layer chromatography, and then analyzed by infrared, nuclear magnetic resonance and gas chromatography-mass spectrometry, chromatographic separations and oxidative degradation. These analytical data proved that the octadecenoic acid wascis-vaccenic acid (cis-11-octadecenoic acid). The concentration of this acid in total octadecenoic acids ranged from 35% to 50% in the pulp of mangoes from Fiji, Mexico, the Philippines and Taiwan.cis-Vaccenic acid was revealed to be one of the major component fatty acids of non-polar lipids (mainly triacylglycerols), glycolipids and phospholipids in mango pulp. The glycolipids containedcis-vaccenic acid (ca. 20%) in higher concentration than oleic acid (ca. 15%). A trace amount ofcis-vaccenic acid (0.5%) was detected in the total lipids of mango seeds. Profile of fatty acid composition of mango pulp lipids (0.2–0.3 wt% of wet pulp) was characterized by the presence of n−7 acid isomers,cis-vaccenic acid and palmitoleic acid, and unusual mono- and dienoic positional isomers.     

Occurrence of n−5 monounsaturated fatty acids in jujube pulp lipids

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.     

Application of a GC-MS method using deuterated fatty acids for tracingcis-vaccenic acid biosynthesis in kaki pulp

A gas chromatographic-mass spectrometric method using [2,2-²H₂]fatty acids has been developed to trace the biosynthesis ofcis-vaccenic (cis-11-octadecenoic) acid in higher plants. The deuterated fatty acids and other unlabeled fatty acids in the biosynthetic reaction mixture were converted into bis(methylthio) derivatives and analyzed by mass chromatography. The principle of this method was based on the shift of key fragment ions (containing two deuterium atoms) due to the cleavage between the methylthio-substituted carbons. The labeled compounds were detected by the m/z values which shifted 2 mass units from those of the corresponding unlabeled compounds and estimated by a calibration curve based on the peak areas of the key fragment ions. For metabolic experiments, a homogenate fraction was prepared from the pulp part of maturing kaki (Diospyros kaki) fruit and incubated with ammonium [2,2-²H₂]palmitoleate (cis-9-hexadecenoate) or [2,2-²H₂]palmitoleoyl-CoA. The incubation resulted in the formation of detectable amounts of isotopically-labeledcis-vaccenic acid containing two deuterium atoms at the carbon chain between the double bond and the carboxyl group. This experimental evidence proved thatcis-vaccenic acid was formed from palmitoleic acid by chain elongation.     

Dibutyrate derivatization of monoacylglycerols for the resolution of regioisomers of oleic, petroselinic, and cis-vaccenic acids

Dibutyrate derivatives of monoacylglycerols of oleic, petroselinic, and cis-vaccenic acids were prepared by diesterification of monoacylglycerols with n-butyryl chloride. The resulting triacylglycerols were analyzed by gas chromatography (GC) with a 65% phenyl methyl silicone capillary column and separated on the basis of both fatty acid composition and regiospecific position. The petroselinic acid derivatives eluted first, followed sequentially by the oleic and cis-vaccenic acid derivatives, with the sn−2 positional isomer eluting before the sn−1(3) isomer in each case. Separation of the peaks was almost baseline between petroselinic and oleic acids as well as between oleic and cis-vaccenic acids. To assess the accuracy of the method, mixtures of triolein, tripetroselinin, and tri-cis-vaccenin in various known proportions were partially deacylated with the use of ethyl magnesium bromide and derivatized and analyzed as above. The results showed that this method compares favorably to the existing methods for analysis of oleic, petroselinic, and cis-vaccenic fatty acids by GC with respect to peak separation and accuracy, and it also provides information on the regiospecific distribution of the fatty acids. The method was applied to basil (Ocimum basilicum) and coriander (Coriandrum sativum) seed oils. cis-Vaccenic, oleic, and linoleic acids were mainly distributed at the sn−2 position in basil seed oil, and higher proportions of linolenic, palmitic, and stearic acids were distributed at the sn−1(3) position than at the sn−2 position. In coriander seed oil, petroselinic acid was mainly distributed at the sn−1(3) position, and both oleic and linoleic acids were mostly located at the sn−2 position, whereas palmitic, stearic, and cis-vaccenic acids were located only at the sn−1(3) position.     

Positional distribution of fatty acids in cardiolipin of mitochondria from 21-day-old rats

Pure cardiolipins (1,3-diphosphatidylglycerol) were prepared from mitochondria of heart, liver and kidney from 21-day-old male Wistar rats and submitted toNaja naja venom phospholipase A₂ (EC 3.1.1.4) action. Incubation conditions were controlled carefully, and a complete hydrolysis of cardiolipin to lysocardiolipin {di [1 (1″) acylsn-glycero-3-phosphoryl] 1′, 3′-sn-glycerol} and fatty acids from positions 2 (2″) was obtained in less than two hr practically without side reactions. Cardiolipins from the three organs contained low levels of saturated fatty acids; stearic acid accounted for 0.4–0.7% and palmitic acid for 1.4–3.5% of total fatty acids. These percentages apparently depended on the organ. In all three cases, linoleic acid was the major component, but its percentage varied from 62–78% of total fatty acids. Acyl chains linked to positions 1 (1″) of all three cardiolipin preparations exhibited a similar pattern; they were composed of linoleic acid for 85–89%. This fatty acid also was the main component esterified at position 2 (2″), but its percentage was much more variable: from 39.8% in heart to 51.2% in kidney and 67.8% in liver mitochondria. The remaining acids comprised octadecenoic and polyunsaturated fatty acids with more than 18 carbon atoms in different proportions. As opposed to other phospholipids,cis-vaccenic acid, and not oleic acid, was the main octadecenoic acid present in cardiolipins. Octadecenoic acids were nine- to 10-fold more concentrated at positions 2 (2″) than at positions 1 (1″). The percentage ofcis-vaccenic acid was four- to five-fold higher than that of oleic acid at positions 2 (2″), whereas oleic acid dominated at positions 1 (1″). From results presented in this study and selected literature data, it may be concluded that fatty acids are asymmetrically distributed in cardiolipins of different origins, with linoleic acid showing a definite preference for position 1 (1″).     

Lactobacillic and methyl-branched olefinic acids inByrsocarpus coccineus seed oil

A detailed investigation of the seed oil ofByrsocarpus coccineus Schum. and Thonn. has disclosedcis-11,12-methyleneoctadecanoic (lactobacillic) (13%) and two branched octadecenoic acids (0.1%). Other fatty acids in the oil are those normally associated with seed lipids except for an unusually high proportion (12%) ofcis-11-octadecenoic acid. Lactobacillic acid has long been known as a constituent of certain bacterial lipids, but this is the first report of its presence in a seed oil. The branched olefinic acids have not heretofore been found to occur in plants. Mention of firm names or trade products does not imply endorsement or recommendation by the Department of Agriculture over other firms or similar products not mentioned.     

Placental transport oftrans fatty acids in the rat

Placental transport of 9-trans [1-¹⁴C] octadecenoic (elaidic) and 9-trans,12-trans [1-¹⁴C] octadecadienoic (linoelaidic) acids was demonstrated in rats. On the 18th day of gestation, a¹⁴C-labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparison, 9-cis [1-¹⁴C] octadecenoic (oleic) or 9-cis,12-cis [1-¹⁴C] octadecadienoic (linoleic) acid also was injected into the maternal circulation of rats. All animals were sacrificed 1 hr following injection. Lipid composition and distribution of label were determined in maternal plasma, placental and fetal tissues. Differences in specific activities of plasma, placental and fetal total lipids indicated a decreasing concentration gradient for bothcis andtrans isomers of octadecenoic and octadecadienoic acids. Distribution of radioactivity in various lipid components was determined by thin layer chromatography. Irrespective of the label, the highest percentage of total radioactivity was carried by triglycerides (TG) in maternal plasma (∼60–80%), and was incorporated mainly in phospholipids (PL) of fetal tissues (∼50–60%). A nearly equal distribution of the label was found between PL and TG of placental lipids (∼40%). Radioactivity of fatty acid methyl esters (FAME) determined by radiogas liquid chromatography indicated that after injection of linoelaidate, radioactivity of maternal plasma, placental and fetal tissue FAME was associated only witht,t-18∶2. Following injection of elaidate, all the radioactivity in placental FAME was associated witht-18∶1; however, in fetal tissues, the label was distributed between 16∶0 andt-18∶1. These findings suggest that, in contrast to linoelaidic acid, rat fetal tissues can metabolize elaidic acid via β oxidation to form acetyl CoA and palmitic acid.     

Determination of fatty acids and some undesirable fatty acid isomers in selected Turkish margarines

The fatty acid composition and total trans fatty acid content in 10 margarines produced in Turkey were determined by capillary gas chromatography and Fourier transform‐infrared spectroscopy (FT‐IR) spectroscopy. The fatty acid composition ranged as follows: saturated fatty acids, C16:0 (palmitic) 11.3 to 31.8% and C18:0 (stearic) 5.7 to 8.7%, monounsaturated fatty acids, C18:1 (oleic) 21.8 to 35.7% and C18:1 trans isomers 0.4 to 27.4%, polyunsaturated fatty acid, C18:2 linoleic acid 5.2 to 40.2%. Some positional isomers of C18:1 as cis‐11‐octadecenoic acid varied from 0.7 to 4.6% and cis‐13 trace to 2.4%. The total trans fatty acid contents were between 0.9 and 32.0% when measured with capillary gas chromatography and between 0 and 30.2% with FT‐IR spectroscopy. Some of the margarines analyzed contained trace amount of trans fatty acids which could not be detected by FT‐IR spectroscopy.     

Detection ofcis-vaccenic acid in palm oil by13C NMR spectroscopy

The NMR signals of the carbonyl and olefinic carbons of the oils of some species of palm show some relatively weak peaks at characteristic positions that have not been identified previously. These peaks are most intense in the oil of the speciesElaeis oleifera. On the basis of the chemical shift data of the carbonyl and olefinic carbons of several synthetic monoenic triacylglycerols and of the packed-column gas chromatogram of the methyl esters of the oil ofE. oleifera, the peaks in question are assigned tocis-vaccenic acid (18∶1,[cis]-11).¹³C NMR spectroscopy is an effective technique for the detection ofcis-vaccenic acid and other monounsaturated fatty acids in vegetable oils or fats.     

Lipids of the pawpaw fruit: Asimina triloba

The fatty acid composition and structure of pawpaw fruit (Asimina triloba) triglycerides were examined and found to contain fatty acids ranging from C₆ to C₂₀. Octanoate represented 20% of the fatty acids while other medium-chain fatty acids were present in low amounts. Analysis of the intact triglycerides by high-temperature gas-liquid chromatography gave an unusual three-cycle carbon number distribution. Analysis of triglyceride fractions separated according to degree of unsaturation suggested that one octanoate was paired with diglyceride species containing long-chain fatty acids. Determination of the double-bond positions of monoene fatty acids revealed cis Δ9 and cis Δ11 hexadecenoate and cis Δ9, cis Δ11, and cis Δ13 octadecenoate isomers were present in significant quantities. Octanoate and positional monoene fatty acid isomers were found only in the fruit lipids and not in the seed lipids. Phenacyl esters of fatty acids were found to be useful derivatives for structure determination using multiple types of analyses.     

Reinvestigation of the polymethylene-interrupted 18:2 and 20:2 acids of Ginkgo biloba seed lipids

The fatty acid composition of Ginkgo biloba seed lipids was reinvestigated with particular emphasis on the polymethylene-interrupted octadecadienoic and eicosadienoic acids. Analysis of the picolinyl esters and 4,4-dimethyloxazoline derivatives by capillary gas-liquid chromatography on a highly polar cyanopropyl polysiloxane stationary phase coupled with mass spectrometry revealed the presence of three such acids, with the structures 5,9–18:2, 5,11–18:2, and 5,11–20:2. This indicated that in G. biloba seeds, cis-vaccenic (11–18:1) acid may be a substrate for the Δ5-desaturase characteristic of gymnosperms. The 5,11-18:2 acid was not limited to G. biloba, as it may occur in a few other species. The 5,11-20:2 acid is a common component of the seed lipids from almost all gymnosperm species analyzed so far.     

Separation of petroselinic (cis-6 18:1) and oleic (cis-9 18:1) acids by gas-liquid chromatography of their isopropyl esters

Petroselinic (cis-6 18:1) and oleic (cis-9 18:1) acids that occur together in Umbelliferae seeds can be resolved by gasliquid chromatography (GLC) of their methyl or isopropyl esters on a 50 m × 0.25 mm fused-silica capillary column coated with a 100% cyanopropyl polysiloxane stationary phase (CP Sil 88). The use of isopropyl esters instead of methyl esters increases the difference between equivalent chainlengths from 0.06 carbon unit up to 0.08. This is sufficient to obtain an almost base-line resolution between the two components.cis-Vaccenic acid is completely separated from oleic acid in both derivative forms. GLC of fatty acid isopropyl esters on an appropriate capillary column thus appears to be the simplest means to simultaneously and accurately quantitate petroselinic, oleic andcis-vaccenic acids.     

Occurrence ofcis-5,cis-9-Hexacosadienoic andcis-5,cis-9,cis-19-Hexacosatrienoic acids in the marine spongeMicrociona prolifera

Fatty acid analysis of the total lipids from the marine spongeMicrociona prolifera by gas liquid chromatography on an EGSS-X column revealed two major peaks with equivalent chain length values of 27.08 and 27.74. Each of these components was isolated as a separate band by thin layer chromatography on AgNO₃-silicic acid. Characterization of the two unknowns by IR spectroscopy, NMR, hydrogenation, and gas liquid chromatography revealed that the unknown acids weren-26∶2 andn-26∶3 containing only nonmethylene interruptedcis-double bonds. Reductive ozonolysis identified the 26∶2 ascis-5,cis-9-hexacosadienoic acid and the 26∶3 ascis-5,cis-9,cis-19-hexacosatrienoic acid. Analysis of the fatty acid composition ofMicrociona total lipids showed 14% 26∶2 and 31% 36∶3. The neutral lipids, phosphatidylethanomaline, and phosphatidylserine all contained >41% C₂₆ acids; but only 4% C₂₆ was present in the phosphatidylcholine.     

Nitrogen containing additives in soda pulping of bagasse pith

Unbleached soda pulp was prepared from Egyptian bagasse pith by varying the alkali concentration and the time of heating at the boiling point of the liquor under atmospheric pressure. A linear relationship was observed between the dissolved pith and the dissolved lignin. Pulping with alkali concentration higher than 10% but not exceeding 16% was more effective, since more delignification took place with lower dissolved pith percentage. p- And m-nitrobenzoic acids and also hydroxylamine hydrochloride had a slight or no effect on the yield of the pulps. The alkali solubility percentage of the pulps prepared in the presence of any of the additives was lower than the control pulp. The delignification was enhanced more on the addition of hydroxylamine hydrochloride than p-nitrobenzoic acid, while m-nitrobenzoic acid seemed to have no effect. The yield of the pulps thus prepared, as determined by weighing, showed lower values than those determined by a chemical method. The soda delignification rate was shown to be proportional to the amount of unremoved lignin and the concentration of alkali in the liquor. The delignification reaction was found to follow approximately first-order kinetics.     

Positional specificity oftrans fatty acids in fetal lecithin

Differences in the positional incorporation of 9-trans[1-¹⁴C] octadecenoic (elaidic) and 9-trans,12-trans[1-¹⁴C] octadecadienoic (linoelaidic) acids in fetal lecithin of rats were demonstrated. On the 20th day of gestation, a¹⁴C-labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparative purposes, 9-cis[1-¹⁴C] octadecenoic (oleic) or 9-cis,12-cis[1-¹⁴C] octadecadienoic (linoleic acid) was injected into the maternal circulation of rats. Animals were killed 6 hr later. Distribution of label in total lipids and phospholipids (PL) of fetal tissue was measured by TLC. Irrespective of the label, the highest percentage of total radioactivity was associated with PL-59 to 67%. Within PL, the major portion of radioactivity was found in choline phosphoglycerides (CPG)-53 to 67%, and in ethanolamine phosphoglycerides (EPG)-18 to 33%. While linoelaidic acid was predominantly esterified in the 2-position of CPG, elaidic acid was nearly equally distributed between positions 1 and 2 of lecithin. Distribution of radioactivity within fatty acid methyl esters (FAME) of CPG measured by radio-GLC suggested that oleic and possibly linoleic acids may be converted to nervonic and arachidonic acid, respectively, in the rat by the 20th day of gestation. Following injection of elaidate, radioactivity of FAME was distributed between palmitate and elaidic acid indicating that rat fetal tissue may metabolize elaidic acid via β-oxidation. In contrast, following injection of linoelaidate, radioactivity of FAME was primarily associated withtt-18∶2, suggesting little biotransformation to other fatty acids by fetal tissues.     

Fatty acids in echinoidea: Unusualcis-5-olefinic acids as distinctive lipid components in sea urchins

Open tubular gas liquid chromatographic (GLC) analyses of fatty acids from total lipids of 12 species of Echinoidea collected at several locations along the Pacific coast of Japan showed the same unusualcis-5-olefinic acids in all species, i.e.,cis-5-octadecenoic acid (5–18∶1),cis-5-eicosenoic acid (5–20∶1), all-cis-5,11- and 5,13-eicosadienoic acids (5,11- and 5,13–20∶2), allcis-5,11,14-eicosatrienoic acid (5,11,14–20∶3) and all-cis-5,11,14,17-eicosatetraenoic acid (5,11,14,17–20∶4). The structural analysis of partially purified 5,11,14,17–20∶4 was undertaken by reductive ozonolysis with GLC and gas chromatographic-mass spectrometric analyses of the products.¹³C-Nuclear magnetic resonance analyses of the totals and fractions of fatty acid methyl esters from the sea urchin lipids did not show any occurrence of fatty acids having an isolated olefinic bond in the 2, 3 or 4 positions. The 5-olefinic acids were concentrated on the polar lipids rather than neutral lipids. The branched and odd chain fatty acid contents of mud-feeding sea urchins were found to be relatively greater proportions of total fatty acids than in algae feeders.     

Effect of early postnatal dietary sterculate on the fatty acid composition of rat liver and brain lipids

Pregnant rats were fed a high carbohydrate diet containing either 1% trilinolein or 1% trilinolein with 0.2% methyl sterculate from 18 day gestation to 21 day postpartum. The pups were weaned at 21 days and continued on the same diet for an additional 10 days. The microsomal stearyl CoA desaturase activities of the liver were effectively inhibited. Liver triglycerides showed increases in the saturated fatty acids concentrations at the expense of the corresponding monoenes. The concentration ofcis 6–7 octadecenoic acid was elevated. In liver phospholipids, the concentration of stearic acid was increased without a corresponding decrease in the oleic acid content. A drastic decrease in the nervonic acid (24∶1, n−9) concentration of liver sphingomyelin was observed. The lipids of the brain did not contain sterculic acid, and brain desaturase activity was unaffected. There was no significant change in the concentration of monoenoic acids from 16∶1 to 22∶1. However, nervonic acid was decreased by 32%. These results suggest that brain nervonic acid may be derived from a precursor other than oleic acid.     

Metabolic aspects of positional monounsaturated fatty acids isomers

Absorption and distribution of positionalcis andtrans octadecenoic acid isomers in lipids from rat, egg and human tissues are reviewed. Selected data on enzyme, single-cell, and whole-animal studies with positional octadecenoic acid isomers are summarized and compared.     

Fatty acid and conjugated linoleic acid isomer profiles in human milk fat

The fatty acid composition of 39 mature human milk samples from four Spanish women collected between 2 and 18 weeks during lactation was studied by gas chromatography. The conjugated linoleic acid (CLA) isomer profile was also determined by silver‐ion HPLC (Ag⁺‐HPLC) with three columns in series. The major fatty acid fraction in milk lipids throughout lactation was represented by the monounsaturated fatty acids, with oleic acid being the predominant compound (36–49% of total fatty acids). The saturated fatty acid fraction represented more than 35% of the total fatty acids, and polyunsaturated fatty acids ranged on average between 10 and 13%. Mean values of total CLA varied from 0.12 to 0.15% of total fatty acids. The complex mixture of CLA isomers was separated by Ag⁺‐HPLC. Rumenic acid (RA, cis‐9 trans‐11 C18:2) was the major isomer, representing more than 60% of total CLA. Trans‐9 trans‐11 and 7‐9 (cis‐trans + trans‐cis) C18:2 were the main CLA isomers after RA. Very small amounts of 8‐10 and 10‐12 C18:2 (cis‐trans + trans‐cis) isomers were detected, as were different proportions of cis‐11 trans‐13 and trans‐11 cis‐13 C18:2. Although most of the isomers were present in all samples, their concentrations varied considerably.     

Synthesis of octadecynoic acids and [1-14C] labeled isomers of octadecenoic acids

Geometric and positional isomers of [1-¹⁴C] octadecenoic acids have been synthesized by modifications of published procedures. Positional isomers of octadecynoic acids also have been synthesized to obtain the geometric and positional isomers of the unlabeled octadecenoic acid analogs. The syntheses were accomplished by coupling a haloalkyl compound with a substituted acetylene using n-butyl lithium in hexamethylphosphoramide. The coupled product, either a 17-or 18-carbon acetylenic alcohol, could be semihydrogenated and chain extended to afford a carboxy labeled derivative, could be partially hydrogenated and chain extended to afford a carboxyl labeledcis-ortrans-octadecenoic acid in the former case. In the latter case, octadecynoic,cis-octadecenoic ortrans-octadecenoic acids could be obtained by the appropriate reactions. The methods used in this study enabled the synthesis of¹⁴C-labeled fatty acids in generally higher yields and by simpler reactions than were previously possible.