Plant sterol esters lower plasma lipids and most carotenoids in mildly hypercholesterolemic adults

The ability of plant sterol esters (PSE) in salad dressing to modify plasma lipids and carotenoids was determined in 26 men and 27 women fed controlled, weight-maintaining, isocaloric diets. Diets contained typical American foods that provided 32% of energy from fat. Dressings contained 8 g (ranch) or 4 g (Italian) of fat per serving. PSF (3.6 g/d) were provided in two servings/d of one of the dressings. Diets with ranch or Italian dressing without and with PSE were fed for 3 wk/diet and crossed over randomly within dressings. Diets were adjusted to similar fat and fatty acid concentrations. Type of salad dressing did not affect plasma lipids, lipoproteins, carotenoids, or fat-soluble vitamins (P>0.05). Switching from a self-selected baseline diet to the control diet resulted in reduction in low density lipoprotein (LDL) cholesterol of 7.9%, a decrease in high density lipoprotein (HDL) cholesterol of 3.1%, and a decrease in triglycerides (TG) of 9.3%. Consumption of 3.6 g of PSE resulted in further decreases in LDL cholesterol (9.7%) and TG (7.3%) but no additional change in HDL cholesterol. Total plasma carotenoids decreased 9.6% with PSE. An automated stepwise procedure was developed to produce candidate mixed models relating plasma carotenoid response to PSE. These models adjusted for preintervention plasma carotenoid levels and effects of diets on blood lipids. There were significant decreases in β-carotene, α-carotene, and β-cryptoxanthin (females only) not associated with changes in plasma lipids. Plasma carotenoids on all diets remained within normal ranges. We conclude that low-fat foods, such as salad dressings, are effective carriers for PSE.     

Castor-based derivatives: Synthesis of some acrylate esters

Acrylate esters of various hydroxy acid derivatives obtainable from castor oil have been synthesized and characterized. Synthetic methods evaluated include acid- and base-catalyzed alcoholysis of methyl acrylate, esterification with acrylic acid, acrylyl chloride, or acrylic anhydride, and esterification with β-chloropropionyl chloride or anhydride followed by dehydrohalogenation. The two-step esterification-dehydrohalogenation procedure gives most satisfactory yields and purity. Preparation, purification, and characterization of the compounds are described and the various synthetic methods are evaluated. Presented in part at the AOCS Meeting, New Orleans, April 1964. W. Utiliz. Res. Dev. Div., ARS, USDA.     

Medium chain triglycerides and structured lipids

Lipids are an essential component of our body composition and necessary in our daily food intake. Conventional fats and oils are composed of glycerides of long chain fatty acids and are designated as long chain triglycerides (LCT). Body fat as well as the fats and oils in our daily intake fall into this category. In enteral and parenteral hyperalimentation, we can identify such LCT fats and oils. Soy, corn, safflower and sunflowerseed oils are typical of the LCT oils. In the search for alternative noncarbohydrate fuels, medium chain triglycerides (MCT) are unique and have established themselves in the areas of malabsorption syndrome cases and infant care and as a high energy, rapidly available fuel. Structure lipids with a MCT backbone and linoleic acid built into the triglyceride molecule have been developed to optimize the triglyceride structure that is best for patients, particularly the critically ill. Structured lipids with built-in essential fatty acid components or other polyunsaturated fatty acids promise greater flexibility in patient care and nitrogen support.     

Synthesis of sulfur-Containing derivatives from olefinic fatty esters

The reaction of 3-mercaptopropan-l,2-diol with methyl 10-undecenoate (Ib) yielded three products, methyl 11-(3′-mercaptopropan-l′,2′-diacetoxy) undecanoate (II, 48.9%), methyl 11-(1-oxapropan-2′-acetoxy-3′-mercaptoacetyl) undecanoate (III, 27.4%) and methyl 10-(3′-mercaptopropan-1′-acetoxy-2′-ol) undecanoate (IV, 23.0%) along with hydrolyzed starting material (Ia, 5.4%). The same reaction with methyl 9-octadecenoate (Vb) gave an isomeric product, 9(10)-(3′-mercaptopropan-l′-acetoxy-2′-ol) octadecanoic acid (VI, 78.5%) and oleic acid (Va, 21.4%). Reaction withtrans-2-octadecenoic acid (VII) afforded 2(3)-(3′-mercaptopropan-l′-acetoxy-2′-ol) octadecanoic acid (VIII, 85.7%).     

Heats of combustion of fatty esters and triglycerides

Gross heats of combustion (HG) have been measured for three classes of fatty esters and two classes of triglycerides (TGs). The esters included saturated methyl esters, Me 6:0–22:0; saturated ethyl esters, Et 8:0–22:0; and unsaturated methyl esters, Me 12:1–22:1, Me 18:2 and Me 18:3. The TGs included the saturated TGs, C 8:0–22:0, and unsaturated TGs, C 11:1, C 16:1, C 18:1, C 18:2, C 18:3, C 20:1 and C 22:1. HG were measured in a Parr adiabatic calorimeter according to a modification of ASTM D240 and D2015. Linear regression analysis (LINREG) yielded equations that related HG to carbon number (CN) or chain length, electron number (EN) or number of valence electrons and molecular weight (MW). Calculated HG values from CN, EN, or MW were nearly identical. Thus, any one of these three variables can be used to predict HG satisfactorily. R squared values for all equations were 0.99. Equations for correlating HG of saturated or unsaturated TGs with molecular characteristics of these molecules have not been reported. With LINREG, we developed equations that permitted predictions of HG from structures of the saturated and unsaturated TGs. Equations for predicting HG of methyl and ethyl esters were compared to those in the literature and were found to be more accurate and precise. Presented in part at the AOCS meeting in New Orleans, LA, in May 1987.     

Wax esters in fish: Turnover of oleic acid in wax esters and triglycerides of gouramis

Methyl U-¹⁴C oleate was fed to mature male and female gouramis (Trichogaster cosby) and the radioactivity in lipids measured over a period of four months. Initial incorporations were 70–80% and more than half of that was still in the lipids at the end of the experiment. Very little conversion of the 18∶1 chain had occurred. Main storage of the labeled 18∶1 chain was in the wax esters of the roe and in the triglycerides of the body. In the wax esters, 18∶1 occurred in both the alcohol and acid moieties. Initially the females had less radioactivity in the triglycerides than in the wax esters but at the end of the experiment this was reversed. An appreciable amount of 18∶1 had been transferred from roe to body lipids. The biological half life of 18∶1 in gouramis is estimated to be about four months. This time is equal for males and females although translocation from roe to body and transformation of wax ester to triglyceride take place in the female, whereas wax esters do not play any role in the lipid metabolism of the male.     

Radiolysis of lipids: Mode of cleavage in simple triglycerides

The effect of gamma radiation on simple triglycerides was investigated. Trilaurin, trimyristin, tripalmitin, tristearin, tripalmitolein, triolein and trilinolenin were irradiated under vacuum at 6 megarads. The volatile breakdown products were separated by vacuum distillation and identified by gas chromatography and mass spectrometry. Qualitative and quantitative data show that the cleavage in fatty acids essentially follows a specific pattern and is not random. A mechanism of radiolysis is proposed.     

Isothiocyanate derivatives of soybean oil triglycerides: Synthesis,characterization, and polymerization with polyols and polyamines

In this article, a novel two step synthesis of soy oil based isothiocyanate is described. Allylicaly brominated soybean oil (ABSO) was reacted first with ammonium thiocyanate in tetrahydro furan to form allylic thiocyanates. These compounds were then converted to isothiocyanated soybean oil (ITSO) by a thermal rearrangement. Conversion was found to be 70%. The structure of the ITSO was characterized by IR and ¹ H‐NMR techniques. Then ITSO was reacted with ethylene glycol, glycerol, and castor oil to produce polythiourethanes and ethylene diamine and triethylene tetra amine to produce polythioureas. Thermal properties of the products were determined by DSC and TGA techniques. DSC traces showed T_g's for ethylene glycol polythiourethane at ?39 and 58°C, for glycerol polythiourethane at ?39 and 126°C, for castor oil polythiourethane at ?38°C and ?17°C, for ethylene diamine polythiourea at ?45°C, and for triethylene tetra amine poly thiourea at ?39°C. Additionally, DSC analysis of polythioureas showed an endotherm at around 100°C. All of the polymers started to decompose around 200°C. Tensile properties of the polymers were determined. Polythiourethanes showed higher tensile strength and lower elongation when compared with their urea analogs. Stress at break values of the polymers were 1.2 MPa for glycerol polythiourethane, 0.6 MPa for ethylene glycol polythiourethane, 0.5 MPa for ethylene diamine polythiourea, and 0.9 MPa for triethylene tetra amine polythiourea polymers. Unfortunately, polymers synthesized showed poor solvent resistance. All polymers swelled and disintegrated in CH₂Cl₂ in 5 h. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Sterol galactosides and sterol esters of the cotton bud

About 60% of the total sterols in the cotton bud appeared in the free state; the esterified sterol glycosides contained about 50% saturated fatty acids, largely palmitic acid; the principal unsaturated fatty acid was linolenic acid. β-Sitosterol was the major sterol in all classes of sterol derivatives. The sugar moiety of the esterified sterol glycosides and the sterol glycoside was galactose. Efforts are continuing to evaluate the minor sterols of cotton buds, some of which appear to be hydroxylated ecdysones, and to study their relationship to the development of the Boll weevil,Anthonomus grandis Boheman.     

Tumor lipids: Carbon number distribution of triglycerides and glyceryl ether diesters

Triglycerides and glyceryl ether diesters were isolated from a number of transplantable rat and mouse tumors and analyzed intact by gas liquid chromatography (GLC). The carbon number distributions of the triglycerides were distinctly different from those of the glyceryl ether diesters. Both glyceride classes contained abnormally high molecular weight species. The data support earlier evidence that indicated diglycerides used for the biosynthesis of phosphatides are also precursors of triglycerides in neoplasms. Glycerides isolated from three centrifuged fractions of Ehrlich ascites cells exhibited similar carbon number distributions. The results indicate a random distribution of triglyceride and glyceryl ether diester molecular species among cellular organeiles. Triglycerides, glyceryl ether diesters and neutral plasmalogens of the same carbon number were partially resolved by GLC. Under contract with the U.S. Atomic Energy Commission.     

Temperature-enhanced alumina HPLC method for the analysis of wax esters,sterol esters,and methyl esters

Previous attempts at separating nonpolar lipid esters (including wax esters, sterol esters, and methyl esters) have achieved only limited success. Among the several normal-phase methods tested, a single recent report of a method employing an alumina column at 30°C with a binary gradient system was the most promising. In the current study, modification of the alumina method by increasing the column temperature to 75°C improved the separation of standards of wax esters and sterol esters. Elevated column temperature also enhanced the separation of FAME with differing degrees of unsaturation. Evidence was also presented to indicate that the method similarly separated phytosterol esters, based on their levels of unsaturation. With the increased interest in phytosterol- and phytostanol esterenriched functional foods, this method should provide a technique to characterize and compare these products.     

Synthesis of plant sterol esters catalyzed by heteropolyacid in a solvent‐free system

The synthesis of phytosteryl esters is of importance due to their recent recognition and application as cholesterol‐lowering agents in the food and nutraceutical industries. In this study, a synthetic route potentially useful for the large‐scale production of food‐grade phytosteryl esters with high yield and purity in a solvent‐free system was investigated. To examine the feasibility of replacing sodium methylate by heteropolyacid, four heteropolyacids, tungstosilicic acid, tungstophosphoric acid, molybdosilicic acid and molybdophosphoric acid, were evaluated to determine the best catalyst and the optimum conditions for the esterification reaction between various fatty acids and phytosterols. The results suggested that tungstosilicic acid was more selective towards butyric acid and caprylic acid than towards lauric acid, palmitic acid, and oleic acid. However, there was no significant discrimination in terms of the tungstosilicic acid catalyst's selectivity to stearic acid, oleic acid, linoleic acid and alpha‐linolenic acid, all with C18 chains, in the esterification reaction. The yield of phytosteryl ester was higher than 90% when the esterification reaction was carried out at 150 °C, with phytosterols and fatty acids in a molar ratio of 1 : 1.5, and catalyzed by 0.2% tungstosilicic acid in silica gel. The catalysts recovery experiments suggested that the immobilized tungstosilicic acid did not significantly lose its activity in six operation runs. As a result, the immobilized tungstosilicic acid would be a promising catalyst for replacing sodium methylate, to synthesize phytosteryl esters with fatty acids and phytosterols as the starting materials in a commercial production.     

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.     

Fullerene lipids: Synthesis of novel nitrogen-bridged [60]fullerene fatty ester derivatives

Reactions of methyl 6-azido-hexanoate, 8-azido-octanoate, and 12-azido-dodecanoate with [60]fullerene (1) gave the corresponding aza-[60]fullerene ester derivatives (2a-2c, 22–35% based on the amount of [60]fullerene reacted). The nitrogen atom is bonded to the [60]fullerene cage to yield a “[5,6]-open” type aza substructure. This was confirmed by the appearance of 30–31 sp ² signals at δ_C 133–147 in the carbon nuclear magnetic resonance spectra. Reaction of methyl 11-azido-7-undecynoate with [60]fullerene furnished a mixture of aza-[60]fullerene (2d, 53%) and aziridine-[60]fullerene (2e, 38%) ester derivatives. Compound 2e was identified as the “[6,6]-closed” type aziridine-[60]fullerene derivative, which displayed 10 sp ² signals in the region δ_C 140–145 and one signal at δ_C 85.05 for the sp ³ carbons of the cage. Refluxing a solution of compound 2d in toluene for 50 h gave about 50% yield of compound 2e, but not vice versa.     

The preparation of alkyl esters from highly unsaturated triglycerides

The alcoholysis reaction has been applied to the preparation of highly unsaturated alkyl esters from menhaden oil. This reaction proceeded very rapidly, and nearly quantitative yields were obtained with virtually, no loss in double-bond structure. The formation of esters was studied, using straight- and branched-chain alcohols having 1–6 carbon atoms. The reactions were monitored by the technique of thin-layer chromatography (TLC). Maximum conversion of straight-chain esters was found to be a linear function with respect to the number of carbon atoms in the alcohol. Reaction time varied from 2 min for methanol to 60 min for n-hexanol. Branched-chain alcohols reacted more slowly than did the corresponding straight-chain compounds. This reaction was found to be applicable to laboratory and large scale preparations of highly unsaturated alkyl esters. Presented at the AOCS meeting, St. Louis, Mo., 1961.     

Synthesis and purification of polyunsaturated triglycerides

Triglycerides (TG) were prepared by the sodium methoxide-catalyzed interesterification of triacetin and the appropriate methyl ester. Yields were optimized and side-reactions were investigated. Silver resin chromatography, utilizing mixed solvent systems (acetonitrile/acetone) was used to separate the resulting TG/methyl ester mixtures. The isolated TG were analyzed by ultraviolet and infrared spectroscopy and were found to contain no conjugated ortrans isomers. They also were analyzed by thin layer chromatography and gas chromatography and found to contain no diacyl-monoacetyl glyceride or other reaction components. Based on higher yield and lack of isomerized byproducts, this procedure was found to be superior in the synthesis of highly unsaturated TG.     

Fatty alcohols in capelin,herring and mackerel oils and muscle lipids: II. A comparison of fatty acids from wax esters with those of triglycerides

The fatty acids recovered from the triglycerides and wax esters of common northwest Atlantic copepods are compared with the fatty acids of wax esters recovered intact from certain fish skin and body lipid, and from commercial fish oils. The fish species, herring, capelin and mackerel, all feed on copepods, and many resemblances of the copepod lipid fatty acids to those of a previous analysis of similar copepods suggest that the basic dietary fat input for these fish may be quite constant. The two copepod fatty acid analyses differed quantitatively in triglyceride 20∶1 and 22∶1 and also in 20∶5ω3 and 22∶6ω3, confirming the primary role of the wax esters in copepods. Selectivity factors are discussed in comparing the copepod wax ester fatty acids with the fatty acids of the wax esters recovered intact from the fish lipids and oils. The basic role of copepods in supplying all types of fatty acids to fish depot fats is considered to be strongly supported by these findings.     

Semiautomatic analysis of serum triglycerides and cholesteryl esters by infrared absorption

An instrument has been developed for the semiautomatic analysis of mixtures of triglycerides and cholesteryl esters. The method is based on high-resolution infrared spectrophotometry, and has previously been shown to be applicable to the determination of these components in the nonionic fraction of human serum lipids. A simple nonrecording grating spectrophotometer has been suitably modified to carry out this analysis; and appropriate computing circuitry has been coupled with it for performing the two-component calculation. The supplementary electronics consist of operational amplifiers, a logarithmic conversion circuit, a digital voltmeter, and a printer. Automatic operation is accomplished by a control mechanism, which programs the measurements, the steps in the calculations, and print-out of the results. Sample preparation consists of an extraction of lipids from serum in such a way as to exelude phospholipids. This may be done in a single step, although a two-step procedure—total lipid extraction followed by adsorption separation of the phospholipids—appears to be more reliable. Measurements are made on a solution of the neutral lipid fraction in carbon tetrachloride.     

Estimation of heat of combustion of triglycerides and fatty acid methyl esters

Equations were developed for the estimation of gross heat of combustion (HG) of triglycerides (TGs) and fatty acid methyl esters (FAMEs) from their saponification number (SN) and iodine value (IV). HG of TG=1,896,000/SN − 0.6 IV — 1600 and HG of FAME=618,000/SN − 0.08 IV — 430. When these equations were tested on cottonseed oil, soybean oil, partially hydrogenated soybean oil, peanut oil, sunflower oil, sunflower oil methyl esters, soybean oil methyl esters and cottonseed oil methyl esters, predicted HG values agreed well with those reported in the literature.