Eicosadienoic Acid Research Articles

The absence of an 8- desaturaseinratliver: A reevaluation of optional pathways for the metabolism of linoleic and linolenic acids

11-[3- 14 C] Octadecenoic acid, 11,14-[1- 14 C] nonadecadienoic acid, 11,14-[1- 14 C] eicosadienoic acid, 11,14-[1- 14 C]heneicosadienoic acid and 11,14,17-[3- 14 C] eicosatrienoic acid were fed and injected into tail veins of rats raised on balanced and fat-free diets. Analysis of the total liver lipids showed that 11–18:1 was not desaturated. In rats raised on a fat-free diet 11,14–19:2 was desaturated to 5,11,14–19:3; 11,14–20:2 was desaturated to 5,11,14–20:3; 11,14–21:2 was desaturated to 5,11,14–21:3 and 11,14,17–20:3 was desaturated to 5,11,14,17–20:4. In rats raised on balanced diets 11,14–19:2 and 11,14–21:2 were desaturated at very slow rates. The 11,1–20:2 and 11,14,17–20:3 were desaturated to 5,11,14–20:3 and 5,11,14,17–20:4 but not as rapidly as in rats raised on fat-free diets. These findings strongly suggest that rat liver does not have a desaturase capable of introducing a double bond in the 8-position during polyunsaturated fatty acids biosynthesis. From these studies it can be concluded that linoleate is only converted to arachidonate via the following pathway: 9,12–18:2 → 6,9,12–18:3 → 8,11,14→ 20:3–5,8,11,14 → 20:4. Linolenate is only metabolized as follows: 9,12,15–18:3 → 6,9,12,15–18:4 → 8,11,14,17–20:4 → 5,8,11,14,17–20:5 → 7,10,13,16,19–22:5 → 4,7,10,13,16,19 → 22:6. Optional pathways such as 9,12 → 18:2 → 11,14–20:2 → 8,11,14–20:3- etc. and 9,12,15–18:3 → 11,14,17–20:3 → 8,11,14,17–20:4 → etc. are inoperative because 11,14–20:2 and 11,14,17–20:3 are probably not produced in vivo and if produced may well be converted to 9,12–18:2 and 9,12,15–18:3, respectively, by retroconversion.

Distribution of dietary elaidic acid in subcellular particles of rat liver

1. 1. Male rats divided into four groups were fed a 20 per cent partially hydrogenated soybean fat, this diet supplemented with 2 per cent corn oil, a fat-free diet, and a regular diet. 2. 2. The fatty acid composition of each lipid class and phospholipid subclass from microsomes, mitochondria, supernatant, fluffy layer, and whole liver was determined. 3. 3. Elaidate incorporated to varying proportions in each of the lipid classes. Triglyceride and cholesterol esters were the richest fractions in elaidate, whereas cardiolipin contained very little of this acid. 4. 4. The fatty acid patterns displayed by triglycerides and phospholipids were the same in all subcellular fractions and in whole liver, whereas cholesterol esters exhibited different fatty acid patterns. 5. 5. Inclusion of dietary linoleic acid into the hydrogenated fat diet facilitated incorporation of elaidic acid in adipose tissue and liver neutral lipids. Its absence from that diet augmented the accumulation of eicosadienoic acids in microsomal and mitochondrial lipids.

Non-methylene-interrupted fatty acids in lipids of shallow-water marine invertebrates: A comparison of two molluscs (Littorina littorea and Lunatia triseriata) with the sand shrimp (Crangon septemspinosus)

1.1. A critical examination of the fatty acids from total lipids and certain lipid fractions of the periwinkle (Littorina littorea), moon snal (Lunatia trisepriata) and sand shrimp (Crangon septemspinosus) has been carried out by open-tubular gas-liquid chromatography.2.2. In the mollusc lipids two sets of novel fatty acids were detected in analyses by open-tubular column gas-lipid chromatography. These had previously been respectively included in packed column analyses with the eicosenoic and docosenoic acids.3.3. These acids are believed to have non-methylene-interrupted structures in which two of the three eicosadienoic acids each have one ethylenic bond in the Δ5 position and the others in positions mimicking the corresponding normal monoethylenic fatty acids, while in two docosadienoic acids the first ethylenic bond is thought to be in the Δ7 position.4.4. These novel fatty acids were not obvious components in the lipids of the sand shrimp which, however, shared with the molluscs emphasis on chain extension of 9-hexadecenoic acid to 13-eicosenoic acid.

Oxidative desaturation of eicosa-8,11-dienoic acid to eicosa-5,8,11-trienoic acid: comparison of different diets on oxidative desaturation at the 5,6 and 6,7 positions

The oxidative desaturation of [1-(14)C]eicosa-8,11-dienoic acid to eicosa-5,8,11-trienoic acid by rat liver microsomes was studied, and the kinetic conditions appropriate to measure the specific activity of the enzyme were determined. A comparative study of the effects of a balanced diet and essential fatty acid-free diets on the oxidative desaturation of oleic and linoleic acids at the 6,7 position and the oxidative desaturation of eicosadienoic acid at the 5,6 position were made. Eicosadienoic acid showed a higher conversion than oleic acid for all the diets. The conversion of oleic and linoleic acids to Delta6 acids was equally increased by fat-free diets with or without added methyl palmitate, whereas the oxidative 5-desaturation of eicosadienoic acid at the 5,6 position was not changed. The effect was apparently independent of the amount of endogenous free fatty acids. The results suggest that the rate-limiting and principal regulatory step in the biosynthesis of eicosa-5,8,11-trienoic acid is the 6-desaturation of oleic acid. The 5-desaturation of eicosadienoic acid was increased by a protein diet and decreased by alloxan diabetes to a lesser extent than the 6-desaturation of linoleic acid. The 5-desaturation of eicosadienoic acid would constitute a secondary regulatory step.

Synthesis of fatty acids from (1- 14 C)acetyl-coenzyme A in subcellular particles of rat epididymal adipose tissue.

1. Mitochondrial and microsomal fractions of rat epididymal adipose tissue incorporated [1-(14)C]acetyl-CoA equally well into various fatty acids by a chain-elongation mechanism. C(18) and C(20) fatty acids were the two major products, and comprised about 80% of the total fatty acids synthesized in both particles. 2. When incubated in air, mitochondria synthesized stearic acid, octadecenoic acid and eicosamonoenoic acid in almost equal amounts (about 20% each), whereas in microsomal fractions, the synthesis of octadecenoic acid was more than fivefold the stearic acid formation. In both fractions, major components of synthesized monoenoic fatty acids were the Delta(11:12) isomers. Hexadecenoic acid and octadecenoic acid from whole adipose tissue contained approx. 11 and 14% of the Delta(11:12) isomer respectively. 3. When mitochondria or microsomal fractions were incubated in nitrogen, there was increased synthesis of stearic acid and palmitic acid and less of C(16) and C(18) monoenoic acids; synthesis of C(20) acids remained predominantly of the monoenoic acids. Determination of the position of the double bond in the monoenoic acids supported the view that the synthesis of hexadecenoic acid and octadecenoic acid involves a desaturase activity, whereas eicosamonoenoic acid and eicosadienoic acid are formed only by elongation of endogenous fatty acids. 4. Most of the radioactivity was found in free fatty acids (63%) and the phospholipid (26%) fraction. In phospholipids, phosphatidylcholine and phosphatidylethanolamine were the two major components. 5. Most of the fatty acids synthesized, including those not normally found in particle lipids (arachidic acid, eicosamonoenoic acid and eicosadienoic acid) were distributed fairly evenly in the phospholipid and free fatty acid fractions. However, stearic acid was found predominantly in the phospholipid fraction.

Kinetic Studies on the Specificity of Long Chain Acyl Coenzyme A Synthetase from Rat Liver Microsomes

Abstract The kinetics of activation of unsaturated and saturated fatty acids by long chain acyl-CoA synthetase from rat liver microsomes has been studied with a method of selective extraction of free fatty acids based on the insolubility of acyl-CoA in diethyl ether. All unsaturated fatty acids with a double bond in Δ9 position (palmitoleate, oleate, linoleate, linolenate) have values of Km in the same range (1.39 to 2.22 µm) and values of Vmax which vary from 9.09 to 18.52 µmoles per hour per mg of protein. These fatty acids are competitive inhibitors of the activation of each other. Each of these fatty acids has the same Ki (1.23 µm) for the inhibition of linolenic acid activation. Some of the metabolites of linoleic acid, eicosa-11,14-dienoic, eicosa-8,11,14-trienoic, and eicosa-5,8,11,14-tetraenoic acids, and of linolenic acid, eicosa-11,14,17-trienoic acid, are also competitive inhibitors of the activation of palmitoleic acid: the two eicosatrienoic acids are the strongest inhibitors (Ki = 4.2 µm), followed by the eicosatetraenoic acid (Ki = 5.0 µm), and by the eicosadienoic acid (Ki = 7.0 µm). The Km values for CoA in the activation of palmitic and oleic acids are, respectively, 7.2 and 9.4 µm. The Km for activation of palmitic acid is 2.78 µm with a Vmax = 14.29 µmoles per hour per mg of protein. Palmitic acid is also a competitive inhibitor of linolenic acid activation with the same Ki (1.23 µm) as that of unsaturated fatty acids with a Δ9 double bond. Similarly palmitic and stearic acids are competitive inhibitors of palmitoleic acid activation (Ki = 2.4 and 17.3 µm, respectively). These results lead to the theoretical conclusion that there is probably only one long chain acyl-CoA synthetase which contains several active sites: a main site which may bind the carboxyl group, and therefore would be the same for all substrates, and secondary sites (or spatial configuration) to accommodate the different types of fatty acid molecules.

Occurrence of Eicosadienoic Acids in Liver Lipids of Rats Fed Partially Hydrogenated Soybean Fat

Occurrence of Eicosadienoic Acids in Liver Lipids of Rats Fed Partially Hydrogenated Soybean Fat

Separation of the C20 unsaturated fatty acids from rapeseed oil by countercurrent distribution.

A C20 fatty acid mixture (5.9 g), which was obtained from fractional distillation of 95 g methyl esters of rapeseed oil, was subjected to countercurrent distribution. This procedure yielded 4.5 g eicosenoic acid (20∶1), 0.4 g eicosadienoic acid (20∶2), and 0.04 g eicosatrienoic acid (20∶3), 4.7%, .42% and .04%, respectively, of the total methyl esters.

Characterization and identification of glyceryl ether diesters in harderian gland tumor of mice

1. 1. The glyceryl ether diesters were identified in Harderian gland tumor of mice by means of thin-layer chromatography, infrared spectrometry, and other chemical methods. The content of glyceryl ether diesters was 59% in total lipids. 2. 2. The ether-bound side chains of the glyceryl ether diesters from tumor lipid were found to be predominant in those of chain length longer than C 20. The content of selachyl alcohol (1- O-octadecenyl alcohol) was remarkably low. 3. 3. The fatty acids of glyceryl ether diesters, especially eicosenoic acid, were also found to predominate in chain length more than C 20. The content of linoleic acid was extremely low and eicosadienoic acid was found in amounts little higher than that of linoleic acid. 4. 4. The triglyceride content was approx. 4% of the total lipids. The fatty acid pattern of the triglycerides differed to some extent from that of the glyceryl ether diesters.

Polyunsaturated fatty acids of aquatic fungi: Possible phylogenetic significance

1. 1. Fatty acids of four marine fungi Thraustochytrium roseum, T. aureum, Schizochytrium aggregatum and Dermocystidium sp. and one fresh-water fungus Phlyctochytrium punctatum were determined. 2. 2. These fungi synthesized ω 3 and ω 6 polyunsaturated fatty acids. They contained large quantities of C 20 and C 22 polyenes; three of the marine fungi contained unusually large amounts of 22:6 fatty acid. 3. 3. Major fatty acids for T. roseum and S. aggregatum were palmitic, oleic and docosahexaenoic acids; for T. aureum, palmitic, docosapentaenoic and docosahexaenoic acids; for Dermocystidium, palmitic, palmitoleic and eicosadienoic acids; for P. punctatum, palmitic, stearic, oleic and linoleic acids. 4. 4. The pattern of biosynthesis of polyunsaturated fatty acids by these aquatic fungi as well as their morphology supports the hypothesis that they evolved from a primitive phytoflagellate (monad) ancestor.

Food Chemical Studies on Soybean Phospholipids

The molecular species of 3-sn-phosphatidylcholine from soybean were determined after convertion into diglyceride acetates by means of hydrolysis with phospholipase C and acetylation with acetic anhydride and pyridine. The resultant diglyceride acetates were separated by thin layer and columnchromatography on silica impregnated with silver nitrate into 7 (LDGA-1-7) and 13 (LDGAA-L) differing with respect to their degree of unsaturation, respectively. Furthermore, the diglyceride acetates were separated by gas liquid chromatography on 3% -JXR on the basis of total carbon number of the fatty acids.As the results, the amount of the 3-sn-phosphatidylcholine composed of total carbon number 36(16+20, 18+18), 34(18+16, 14+20) and 38(20+18) was abundant, and this accorded with the large amount of linolenic acid (59.4%) and palmitic acid (10.6%) in the original 3-sn-phosphatidylcholine. Notwithstanding the original 3-sn-phosphatidylcholine contained arachidonic, eicosatrienoic and eicosadienoic acid in comparatively large quantities, the amount of the 3-sn-phosphatidylcholine composed of total carbon number 40 was scarcely, and this showed that the combination of the fatty acids' carbon number among both ester positions in the 3-sn-phosphatidylcholine were not (20+20), but (12+20), (14+20), (16+20) or (18+20).

Food Chemical Studies of Soybean Phospholipids

Soybean 3-sn-phosphatidylethanolamine was separated by thin-layer chromatography on silica impregnated with silver nitrate into 4 fractions depending on their degree of unsaturation and these fractions were designated as SBE-1, SBE-2, SBE-3 and SBE-4 according to Rf value. The fatty acid component of the SBE-1 was linoleic acid (12.3%) and oleic acid (12.1%) as unsaturated fatty acids. The fatty acid component of the SBE-2 was linoleic acid (36.1%) and arachidonic acid (53.8%) as unsaturated fatty acids. The fatty acid component of the SBE-3 was linolenic acid (19.4%), eicosadienoic (1.9%), eicosatrienoic (1.9%), and arachidonic acid (9.0%) as unsaturated fatty acids. The fatty acid component of the SBE-4 was arachidonic acid (37.8%) as unsaturated fatty acids. On the other hand, the 3-sn-phosphatidylethanolamine was separated into 9 fractions by adsorption columnchromatography on silica impregnated with silver nitrate, and these fractions were designated as fraction 1, 2, 2', 3, 3', 4, 5, 6 and 7. The fatty acid component of these fractions was revealed, and is was found that the fraction 2 was corresponded to the SBE-1 and the fraction 6 was corresponded to the SBE-3.

Chain Elongation of Linoleic Acid and Its Inhibition by Other Fatty Acids in Vitro

Abstract Linoleic acid-1-14C was incubated with subcellular fractions of rat liver to study the mechanism of polyunsaturated fatty acid synthesis. The most effective system for the chain elongation of linoleic acid to eicosadienoic acid was liver microsomes plus malonyl coenzyme A with cofactors, NADPH, and ATP. Under anaerobic conditions, the chain elongation reaction could be separated quantitatively from the dehydrogenation reaction which otherwise required the same system. The chain elongation of linoleic acid was inhibited by saturated fatty acids of which myristic and pentadecanoic acids were most effective. Mono-unsaturated and polyunsaturated fatty acids also act as inhibitors. From consideration of reaction kinetics and inhibition by other fatty acids, the conversion of linoleic acid to γ-linolenic acid seems preferred over the conversion of linoleic acid to homolinoleic acid.

The Separation and Structure Determination of an Eicosatrienoic and an Eicosadienoic Acid in Nagi Seed Oil

The Separation and Structure Determination of an Eicosatrienoic and an Eicosadienoic Acid in Nagi Seed Oil

Separation and Structure Determination of the Eicosatrienoic and Eicosadienoic Acids in the Seed Oil of Podocarpus Nagi

Separation and Structure Determination of the Eicosatrienoic and Eicosadienoic Acids in the Seed Oil of Podocarpus Nagi

COMPOSITION OF DELPHINIUM SEED OIL

The fatty oil of delphinium seed (Delphinium hybridum (Hort.)) was examined. Fresh seed gave an oil composed mainly of glycerides but having 2.8% of free fatty acids. The oil from older seed contained about 50% of free fatty acids, apparently as a result of lipase action in the seed. The total fatty acids were found to include cis-11-eicosenoic acid (18%) and eicosadienoic acid (1%), the latter identified as tetrahydroxyeicosanoic acid. Other acids that were identified and the estimated percentages were: 9-hexadecenoic <1, palmitic 4, linoleic 16, oleic 53, and stearic 1. Spectroscopic analysis indicated a content of 2.5% of octadecatrienoic acid. Eicosoic acids have not been observed previously in the seed oils of this plant family (Ranunculaceae).

柔魚内臓油の成分とその利用に就て

Ultraviolet absorption spectra of the original oil, refined oil and methyl ester of cuttle fish oil, showed the presence of small amount of conjugated dien, trien, tetraen and pentaen fatty acids. But spectrum of the distillated methyl ester showed only the presence of conjugated then and trien, but not of tetraen and pentaen. We found new conjugated eicosadienoic acid in cuttle fish oil, as the maleic acid adduct, which was obtained by the reaction of maleic acid anhydride benzol solution-and C20 fatty acid methyl ester fraction of cuttle fish oil.

Canadian erucic acid oils. VIII. Component fatty acids of the oil from weed seed screenings, largely charlock

SummaryThe oil from weed seed screenings from Western Canadian grain was found to consist of 31% oleic, 27% linoleic, 13% linolenic, 12% eicosenoic, 8.4% erucic, 6.3% saturated, and small amounts and traces of other acids. Eicosenoic acid was found in greater abundance than erucic acid, a result probably related to the fatty acid composition of charlock. The presence of eicosadienoic, eicosatrienoic, and docosatrienoic acids, hitherto unreported in vegetable oils, is strongly suggested.