Unsaturated Fatty Acid Esters Research Articles

Lanthanide induced shift as a tool for isomer assignment in esters of unsaturated fatty acids

Addition of Yb(fod) 3 to methyl oleate ( cis) and methyl elaidate ( trans) shifts the carboxylic lines of their 13C-NMR spectra to different extents; that of the cis isomer less than that of the trans isomer, as is to be expected. On the same theoretical ground it can be anticipated that the opposite will occur for C-17: an effect that has been confirmed experimentally. The method is thus proposed as a means of aiding in the assignment of the cis and trans configuration in esters of fatty acids with one double bond.

Estradiol fatty acid esters. The isolation and identification of the lipoidal derivative of estradiol synthesized in the bovine uterus.

The bovine uterus, like other estrogen-responsive organs of man and rat, synthesizes an unusual nonpolar metabolite of estradiol (Schatz, F., and Hochberg, R. B. (1981) Endocrinology 109, 697-703). This compound, the lipoidal derivative of estradiol (LE2), was synthesized from estradiol by bovine endometrial tissue in vitro, and it was purified by extensive chromatography on two adsorption columns, a reversed phase partition celite column and three different high pressure liquid chromatography columns. LE2 was separated into nine fractions which were analyzed by direct probe mass spectroscopy and by gas chromatography mass spectroscopy after cleavage of the lipoidal moieties. In this manner, 10 fatty acid esters of estradiol, exclusively esterified at C-17 of the steroid nucleus, were identified. The unsaturated fatty acid esters of estradiol comprise more than 85% of the total LE2 and estradiol 17 beta-arachidonate is the most abundant component. The cholesterol esters and phospholipids of the bovine endometrium were also purified and it was found that the distribution of fatty acids in these lipids is far different from that of LE2.

Preparation of surfactants by condensation of fatty acid esters with hydrolyzed proteins

AbstractProducts with good surface‐active properties can be easily prepared by condensation of fatty‐acid methyl esters with polypeptides derived from collagen proteins by hydrolysis. The condensation is done at moderate reaction temperatures (ca. 155 C) in dimethylsulfoxide solvent, and is promoted by sodium hydroxide or other alkaline reagents. The method works best with unsaturated esters, such as methyl oleate, which are more soluble in the reaction mixture, and which yield more soluble products, but also works well with the mixture of saturated and unsaturated fatty acid esters in methyl tallowate. The reaction appears to be a transamidation reaction in which incorporation of the fatty acid moiety results in partial cleavage of the polypeptide chain and in formation of methyl alcohol. Other solvents which can dissolve both fatty acid esters and collagen‐derived proteins, such as ethylene glycol, can be used to advantage in this reaction.

Alkylthiolation for the determination of double-bond position in unsaturated fatty acid esters

The methyl esters of some mono-unsaturated fatty acids have been methylthiolated by the iodine-catalysed addition of dimethyl disulfide across the double bond. The resulting derivatives are suitable for gas chromatography. The fragmentation of the derivatives on electron impact yields mass spectra which allow immediate recognition of the position of the original double bond.

Autoxidation of methyl linolenate and methyl linoleate: The effect of α‐tocopherol

Abstractα‐Tocopherol substantially affects the distribution of peroxidic compounds formed during the autoxidation of methyl linolenate and methyl linoleate. In the autoxidation of both these unsaturated fatty acid esters the proportion of monohydroperoxides with conjugated double bonds in the trans, trans configuration is reduced until at high concentrations of α‐tocopherol (5%) only cis, trans isomers are formed. In the autoxidation of methyl linolenate the proportion of hydroperoxy‐epidioxides is reduced and only monohydroperoxides are formed when 5% α‐tocopherol is present. The results are discussed in terms of recent findings concerning the mechanism of the autoxidation of unsaturated lipids.

Fatty-acid methyl esters dissolved in seawater and associated with suspended particulate material

Methyl esters of saturated and unsaturated fatty acids were isolated as trace components from organic material suspended in seawater. Methyl palmitate and methyl stearate were accumulated from the filtrate by adsorption onto Amberlite XAD-2 resin. Identification of most methyl esters is based on the comparison of gas chromatographic retention indices and mass spectrometric fragmentation with those of authentic standard compounds. In cases where reference substances were not available, identification is based on mass spectrometric and gas chromatographic properties of the unknown compounds.

Specific binding of [ 3H]ouabain to heart is inhibited by long-chain fatty acids and alcohols

Long-chain fatty acids and alcohols inhibit specific binding of [ 3H]ouabain to a particulate fraction from dog heart. The magnitude of inhibition increases with chain length, reaching a maximum with lauric acid, myristoleic acid and decanol in a series of saturated fatty acids, unsaturated fatty acids, and alcohols, respectively, followed by a decline with longer chain members of homologous series. Unsaturated fatty acids and alcohols are more inhibitory than their corresponding saturated congeners; in general, inhibitory potency is greater in cis than trans forms and increases with higher degree of unsaturation. Methyl esters of both saturated and unsaturated fatty acids tested were inactive at 10 −3 m or lower concentrations. The inhibition of ouabain binding by fatty acids and alcohols was specific and appears to be competitive. This study extends our earlier findings on the inhibitory activity of fatty acid fractions from bovine liver.

Lipid fractions from liver inhibit specific binding of [ 3H]ouabain to dog heart

Ethyl acetate extracts of bovine liver contain organic material which inhibits specific binding of [ 3H]ouabain in a radioreceptor binding assay. Filtration of Sephadex LH-60 resolved active material in a cholesterol-rich fraction which was further purified on a silica gel column and by TLC and found by GLC/MS to be composed mainly of long-chain fatty acids and their methyl esters. Certain authentic saturated and unsaturated fatty acids were active in the binding assay: lauric, myristic and myristoleic acids being most active. Since the amount of active saturated acids in the extracts is too small to account for the total observed activity, the presence of active unsaturated fatty acids is indicated. Furthermore, another active unidentified substance was associated with the neutral lipid fraction which also contained cholesterol and methyl esters of palmitic and stearic acids as major identifiable components, and gave a concentration-displacement curve parallel to that of ouabain. Authentic cholesterol and methyl esters of both saturated and unsaturated fatty acids were inactive in the binding assay. Thus, inhibition of specific binding of [ 3H]ouabain by lipid extracts of liver appears to be due, in part, to certain fatty acids and, in addition, to a potent unidentified substance associated with neutral lipids.

THE ISOMERIC COMPOSITIONS OF MONOHYDROPEROXIDES PRODUCED BY OXIDATION OF UNSATURATED FATTY ACID ESTERS WITH SINGLET OXYGEN

The isomeric compositions of monohydroperoxides produced by oxidation of unsaturated fatty acid esters with chemically produced singlet molecular oxygen were determined by mass chromatography as the trimethylsilyl derivatives of hydroxy-octadecanoate. Methyl oleate formed equal amounts of the 9- and 10-isomers. Methyl linoleate formed equal amounts of the four isomeric hydroperoxides, the 9-, 10-, 12- and 13-isomers. Six isomers, the 9-, 10-, 12-, 13-, 15- and 16-isomers, were obtained from the monohydroperoxides of methyl linolenate in which the quantities of the 9- and 16- isomers were slightly higher than those of other isomers. The isomeric compositions of monohydroperoxides obtained by chlorophyll sensitized photooxidation were very similar to those formed by chemically produced singlet oxygen except that the proportions of the 9- and 13-isomers were higher than those of the 10- and 12-isomers in methyl linoleate.

Synthesis of saturated, unsaturated, spin-labeled, and fluorescent cholesteryl esters: Acylation of cholesterol using fatty acid anhydride and 4-pyrrolidinopyridine.

A rapid, high yield method for the preparation of cholesteryl esters is described. The method is a modification of the catalytic procedure previously applied to the acylation of sn-glycero-3-phosphoryl-choline (Patel, K.M., J.D. Morrisett, and J.T. Sparrow, J. Lipid Res., 20:676 (1979). Cholesteryl esters are formed in excellent yield by acylating cholesterol with fatty acid anhydride or fatty acid and dicyclohexylcarbodiimide in methylene chloride containing 4-pyrrolidinopyridine. The versatility of the method is demonstrated by the preparation of the cholesteryl esters of saturated, unsaturated, spinlabeled, and labile fluorescent fatty acids.

A Surface Study of Ozone Attack and Antiozonant Protection of Carbon Black Loaded Natural Rubber Compounds

Abstract This work reports a direct surface analysis of ozonization of carbon black loaded NR compounds by ATR and SEM. On ozonization of raw NR or NR containing carbon black, a thick layer builds up consisting of ozonides and carbonyl compounds. It is suggested that this layer is composed principally of the reaction products of ozone with unsaturated fatty acids and unsaturated fatty acid esters found in NR. On ozonization of cured and uncured carbon black loaded NR compounds containing curatives, the NR is attacked causing a decrease of rubber on the surface and a corresponding increase in the surface concentration of carbon black. The thick ozonide/carbonyl layer did not form, probably due to the coordination of the fatty acids and esters with ZnO, which was added with the curatives. On ozonization of carbon black-loaded NR compounds containing N,N′-dioctyl-p-phenylenediamine antiozonant, a continuous film is seen by SEM which has an ATR spectrum essentially identical to ozonized antiozonant. There is no evidence of ozonized NR products, or of complex reaction products between antiozonant and ozonized NR. These results are consistent with a dual scavenger and protective layer mechanism for antiozonant protection.

Effects of dietary fatty acids on hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity in hamsters on a high-glucose diet

Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity in hamsters given a fat-free high-glucose diet for 21 days was approximately 20 times higher than that in chow-fed hamsters. The increase in enzyme activity by dietary glucose was affected by saturated or unsaturated fatty acids or cholesterol added to the high-glucose diet. Ethyllinoleate or ethyloleate, added to the diet at a concentration of 5%, suppressed the increase in the enzyme activity. In contrast, addition of ethylpalmitate to the diet further stimulated the increase in the enzyme activity. Addition of 2% cholesterol to the high-glucose diet moderately suppressed, and addition of both cholesterol and ethyllinoleate completely prevented, the increase in the enzyme activity. The enzyme activity closely correlated with the incidence of formation of cholesterol gallstones but not with the liver cholesterol level. Marked increase in the enzyme activity was observed by feeding the high-glucose diet to starved hamsters for even a short period. On the third day after feeding was resumed, the enzyme activity was increased 500-fold compared to that during starvation. This increase in the enzyme activity was also reduced by dietary unsaturated fatty acid esters and stimulated by a dietary saturated fatty acid ester.

Replacement of neutral lipids of low density lipoprotein with esters of long chain unsaturated fatty acids.

Replacement of neutral lipids of low density lipoprotein with esters of long chain unsaturated fatty acids.

ChemInform Abstract: HETEROGENEOUS METATHESIS OF UNSATURATED FATTY ACID ESTERS

AbstractRheniumheptoxid auf Aluminiumoxid als Träger katalysiert in Gegenwart von Tetramethylzinn die Metathese des ungesättigten Carbonsäureesters (I) zu (II) und (III).

Role of phospholipids in muscarinic binding by neural membranes

A role for acidic phospholipids in brain muscarinic receptors is suggested by their effect on the specific binding of a potent muscarinic antagonist, tritiated 3-quinuclidinyl benzilate ([ 3H]QNB), to neural membranes. The addition of phosphatidylserine (PS) enhances specific muscarinic binding up to 40 per cent, while phosphatidic acid (PA) and phosphatidylinositol (PI) are less effective, and neutral lipids are generally without effect. Unsaturated fatty acids, but neither saturated fatty acids nor the methyl esters of unsaturated fatty acids, inhibit [ 3H]QNB binding, the amount of inhibition being proportional to the degree of unsaturation. Unsaturation in the phospholipids is also inimical to muscarinic binding. Pretreatment of the membranes with phospholipases A and C decreases binding 100 and 60 per cent respectively. The addition of acidic phospholipids restores some binding activity after phospholipase treatment. Inhibition of [ 3H]QNB binding by low concentrations of cationic detergents is completely reversible by PS and PA. Ionic, pH and temperature effects on QNB binding indicate that the association of QNB with muscarinic receptors involves primarily hydrophobic interactions.

Products formed by photosensitized oxidation of unsaturated fatty acid esters

Abstract and SummaryPhotosensitized oxidation of unsaturated fatty acid methyl ester was carried out using methylene blue as a sensitizer. Oxidation products, monohydro‐peroxides, were identified as trimethylsilyl derivatives. Methyl oleate gave the 9‐ and 10‐isomers; methyl linoleate, the 9‐, 10‐, 12‐, and 13‐isomers; and methyl linolenate, the 9‐, 10‐, 12‐, 13‐, 15‐, and 16‐isomers, respectively. The double bond to which the hydroperoxide group attached was shifted to the adjacent position in each isomer. Thus, both conjugated and nonconjugated isomers were present in methyl linoleate monohydroperoxides and methyl linolenate monohydroperoxides. By the inhibition experiment, it was ascertained that the above reaction proceeded via singlet oxygen. The relative rates of methyl oleate, methyl linoleate, and methyl linolenate were 1.0∶1.7∶2.3, respectively. These results obtained from the methyl esters were applied to the photosensitized oxidation of triglycerides purified from vegetable oils, and the reaction mechanism on triglycerides was proposed.

Experimental investigation of hypolipidemic and anti-atherosclerotic drugs with different mechanism of action.

In the Soviet Union the following drugs are used to reduce the plasma level of cholesterol and triglycerides in patients with hyperlipidemias: miscleron (Clofibrate), nicotinic acid, β-sitosterol and the preparations containing unsaturated fatty acids. Amongst them there are arachiden and conlitol. Arachiden is a mixture of ethyl esters of arachidonic, linoleic, linolenic, pentaene and hexaene acids. It is prepared from the lipid fraction of cattle pancreas. Conlitol is a mixture of ethyl esters of unsaturated fatty acids isolated from linseed oil. Both preparations are used orally.

Heterogeneous metathesis of unsaturated fatty acid esters

Rhenium heptoxide on alumina, promoted by a small amount of tetramethyltin, is an active and very selective catalyst for the heterogeneous metathesis of unsaturated fatty acid esters.

Ozonization products of unsaturated fatty acid methyl esters

Low temperature ozonization of the methyl esters of all- cis nonconjugated fatty acids, containing 1 to 4 double bonds in pentane, gave high yields of normal ozonides of the parent ester as the major product of the reaction. Ozonization of all- cis methyl eicosapentaenoate and docosahexaenoate under the same conditions gave a mixture of normal ozonides containing a large proportion of cross ozonides. Thin-layer chromatography (TLC) of the normal ozonides of the methyl esters of unsaturated fatty acids differing in the number and positions of ozonide groups and in chain length was demonstrated. Fractionation of the parent normal ozonides of methyl linoleate, linolelaidate, linolenate and arachidonate by low temperature crystallization indicated that the normal ozonides of these esters consisted of mixtures of geometric isomers. The ozonization of the methyl esters of all- trans nonconjugated fatty acids gave low yields of normal ozonides of the parent ester by comparison to the corresponding all- cis isomers, and the yield of these ozonides decreased with increasing unsaturation. Infrared spectral analysis showed that the major products of the reaction with these esters contained both hydroxyl and/or peroxy and normal ozonide groups.

Organic resin coated glass fibers coated with unsaturated fatty acid ester : Ward, J. E. Jr and Garick, B. B. (Owens-Corning Fiberglas Corporation) US Pat 3 924 047 (2 Dec 1975)

Organic resin coated glass fibers coated with unsaturated fatty acid ester : Ward, J. E. Jr and Garick, B. B. (Owens-Corning Fiberglas Corporation) US Pat 3 924 047 (2 Dec 1975)