Intestinal and liver fatty acid binding proteins differentially affect fatty acid uptake and esterification in L-cells

Differential effects of intestinal (I-FABP) or liver (L-FABP) fatty acid binding proteins on fatty acid uptake and esterification were examined using transfected mouse L-cell fibroblasts. L-FABP, but not I-FABP, expression increased the initial rate and extent ofcis-parinaric acid uptake by 50 and 29%, respectively, compared to control cells. I-FABP and L-FABP expression preferentially increased [³H]-oleic acid incorporation into triacylglycerols by 5.5-fold and 3.8-fold, respectively. While both L-FABP and I-FABP increasedesterification of [³H]-oleic acid into ethanolamine glycerophospholipids, these proteins had opposite effect on esterification into choline glycerophospholipids. These data show for the first time that distinct FABP differentially affect both fatty acid uptake and intracellular esterification.     

Expression of fatty acyl-CoA binding proteins in colon cells: response to butyrate and transformation

Fatty acyl-CoA affect many cellular functions as well as serving as cellular building blocks. Several families of cytosolic fatty acyl-CoA binding proteins may modulate the activities of fatty acyl-CoA. Intestinal enterocytes contain at least three unique families of cytosolic proteins that bind fatty acyl-CoA: acyl-CoA binding protein (ACBP), fatty acid binding proteins (including the liver, L-FABP and intestinal, I-FABP), and sterol carrier protein-2 (SCP-2). Immortalized rat colon epithelial cell lines expressed only ACBP and SCP-2 at levels of 0.75±0.13 and 0.42±0.02 ng/μg protein. Ras and src transformation increased colon cell density and differentially altered ACBP and SCP-2 expression without affecting I-FABP or L-FABP levels. ACBP levels were 1.8-fold and 1.5-fold increased in ras- and src-transformed cells, respectively. In contrast, SCP-2 expression was significantly decreased 55 and 67% in ras- and src-transformed cells, respectively. Butyrate treatment of ras- and src-transformed cells decreased cell proliferation up to 60–85% as compared to 25–30% in control cells. Butyrate treatment decreased ACBP expression in all cell lines but had no effect on the levels of SCP-2, I-FABP, or L-FABP. These studies suggest that the differential expression of ACBP and SCP-2 in rat colonic cell lines, as well as their modulation by butyrate, may be altered by cell transformation.     

GC-FID/MS Analysis of Fatty Acids in Indian Cultivars of Moringa oleifera: Potential Sources of PUFA

In the present investigation, the fatty acid profile was analysed in vegetative and reproductive parts of eight commercially cultivated Indian cultivars of Moringa oleifera and verified by gas chromatography mass spectra. In leaves, α-linolenic acid (C_18:3, cis-9,12,15) was found in the highest quantity (49–59 %) followed by palmitic acid (C_16:0) (16–18 %), and linoleic acid (C_18:2, cis-9,12) (6–13 %). The total content of saturated fatty acids and unsaturated fatty acids showed a ratio of 0.33 (cv. DHANRAJ) to 0.39 (cv. PKM-2) in leaves, 0.53 in flowers and 0.56 in tender pods. Similarly, polyunsaturated fatty acids and total monounsaturated fatty acids were found in a ratio of 5.68 (cv. DHANRAJ) to 9.71 (cv. CO-1) in leaves, 1.11 in flowers and 2.79 in tender pods. The total lipid content was recorded in the range of 1.92 % (flowers) to 4.82 % (leaves, cv. CO-1). When considering health benefits, M. oleifera leaves contain low amounts of saturated fatty acids, a high mono- and polyunsaturated fatty acid content, which can enhance the health benefits of Moringa-based products.     

Novel branched-chain fatty acids in certain fish oils

Methyl-branched fatty acids, which are usually minor components (≤0.1%) in fish oils, were concentrated in the non-urea-complexing fraction along with polyunsaturated fatty acids during the enrichment of omega-3 fatty acids from certain fish oils via the urea complexation process. The methyl-branched fatty acids in the omega-3 polyunsaturated fatty acid concentrates, which were prepared from three fish body oils, were characterized by gas chromatography and gas chromatography/mass spectrometry. Among the major branched-chain fatty acids expected and identified were the known isoprenoid acids—mainly 4,8,12-trimethyltridecanoic, pristanic, and phytanic—and the well-known iso and anteiso structures. Two novel phytol-derived multimethyl-branched fatty acids, 2,2,6,10,14-pentamethylpentadecanoic and 2,3,7,11,15-pentamethylhexadecanoic, were identified in redfish (Sebastes sp.) oil. These two fatty acids were absent in oils from menhaden (Brevoortia tyrannus) and Pacific salmon (mixed, but mostly from sockeye,Oncorhynchus nerka). The major branched-chain fatty acid in the salmon oil, 7-methyl-7-hexadecenoic acid, was also present to a moderate extent in menhaden oil. A novel vicinal dimethyl-branched fatty acid, 7,8-dimethyl-7-hexadecenoic was detected in all of the fish oils examined, but was most important in the salmon oil. Three monomethyl-branched fatty acids, 11-methyltetradecanoic acid, and 11- and 13-methylhexadecanoic, hitherto undescribed in fish lipids, were also detected in salmon, redfish and menhaden oils. Presented in part at the First Annual Meeting of the Amer. Oil. Chem. Soc. Canadian Section, Guelph, Ontario, Oct. 8–9, 1986.     

Identification of α-parinaric acid in the seed oil ofSebastiana brasiliensis sprengel (Euphorbiaceae)

Besides some usual fatty acids, the seed oil ofSabastiana brasiliensis (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectroscopy) of α-parinaric acid (cis, trans, trans, cis-9, 11, 13, 15-octadecatetraenoic acid). The fatty acids were analyzed by gas chromatography and gas chromatography/mass spectrometry as their methyl esters. The structure of α-parinaric acid was proven by a combination of chemical and spectroscopic methods, conducted with the crude oil, the methyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the¹H and¹³C nuclear magnetic resonance (NMR) shifts of α-parinaric acid was carried out by two-dimensional NMR experiments Presented in part at the 21st world Congress and Exhibition of the International Society for Fat Research (ISF), October 1–6, 1995, The Hague, The Netherlands.     

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.     

<Emphasis Type="Italic">cis</Emphasis>-, <Emphasis Type="Italic">trans</Emphasis>- and Saturated Fatty Acids in Selected Hydrogenated and Refined Vegetable Oils in the Indian Market

The fatty acid composition of 27 samples of commercial hydrogenated vegetable oils and 23 samples of refined oils such as sunflower oil, rice bran oil, soybean oil and RBD palmolein marketed in India were analyzed. Total cis, trans unsaturated fatty acids (TFA) and saturated fatty acids (SFA) were determined. Out of the 27 hydrogenated fats, 11 % had TFA about 1 % where as 11 % had more than 5 % TFA with an average value of about 13.1 %. The 18:1 trans isomers, elaidic acid was the major trans contributor found to have an average value of about 10.8 % among the fats. The unsaturated fatty acids like cis-oleic acid, linoleic acid and α-linolenic acid were in the range of 21.8–40.2, 1.9–12.2, 0.0–0.7 % respectively. Out of the samples, eight fats had fatty acid profiles of low TFA (less than 10 %) and high polyunsaturated fatty acids (PUFA) such as linoleic and α-linolenic acid. They had a maximum TFA content of 7.3 % and PUFA of 11.7 %. Among the samples of refined oils, rice bran oil (5.8 %) and sunflower oil (4.4 %) had the maximum TFA content. RBD palmolein and rice bran oils had maximum saturated fatty acids content of 45.1 and 24.4 % respectively. RBD palmolein had a high monounsaturated fatty acids (MUFA) content of about 43.4 %, sunflower oil had a high linoleic acid content of about 56.1 % and soybean oil had a high α-linolenic acid content of about 5.3 %.     

Effect of dietary fats on desaturase activities and the biosynthesis of fatty acids in rat-liver microsomes

Four groups of rats were fed diets containing 15% (w/w) high-oleic safflower oil (SFO, rich incis-18∶1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H+CO, rich intrans-18∶1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18∶2ω6). Fatty acid composition of liver microsomes and activities of the Δ⁵, Δ⁶ and Δ⁹ desaturases were determined. Microsomal Δ⁶ desaturase activity and arachidonic acid were lower in the H+CO group compared with SFO of L. No difference was found in the Δ⁵ or Δ⁶ desaturase activity of CO and SFO groups. Thus, the oleic-acid level of the SFO diet had no effect on the metabolism of 18∶2ω6. Fluorescent polarization studies, usingtrans-parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that thetrans-18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.     

Cholesterol interaction with recombinant human sterol carrier protein-2

The interaction of human recombinant sterol carrier protein-2 (SCP-2) with sterols was examined. Two independent ligand binding methods, Lipidex 1000 binding of [³H]cholesterol and a fluorescent dehydroergosterol binding assay, were used to determine the affinity of SCP-2 for sterols. Binding analysis indicated SCP-2 bound [³H]cholesterol and dehydroergosterol with aK _d of 0.3 and 1.7 μM, respectively, and suggested the presence of a single binding site. Phase fluorometry and circular dichroism were used to characterize the SCP-2 sterol binding site. Alterations in dehydroergosterol lifetime, SCP-2 tryptophan lifetime, and SCP-2 tryptophan quenching by acrylamide upon cholesterol binding demonstrated a shielding of the SCP-2 tryptophan from the aqueous solvent by bound sterol. Differential polarized phase fluorometry revealed decreased SCP-2 tryptophan rotational correlation time upon cholesterol binding. Circular dichroism of SCP-2 indicated that cholesterol elicited a small decrease in SCP-2 alpha helical content. The data suggest that SCP-2 binds sterols with affinity consistent with a lipid transfer protein that may act either as an aqueous carrier or at a membrane surface to enhance sterol desorption.     

Tuna fatty acids: I. initial studies on the composition of the light and dark meats of bluefin tuna (Thunnus thynnus)-structural isomers of the monoenoic fatty acids

Bluefin tuna (Thunnus thynnus) is consumed in substantial amounts by humans. However, little has been reported on the fatty acid composition of bluefin body oil and on the isomeric structures of the unsaturated fatty acids. Because of the probable nutritional significance of unsaturated fatty acids, the present work was undertaken as an introductory study of the composition and structure of the fatty acids of tuna. The fatty acid composition of the light and dark meats from three bluefin tuna was determined by gas-liquid chromatography. A wide variety of saturated and polyunsaturated fatty acids were present in the oil from the meat of these speciments. the monoemoic fatty acid fraction, which comprises 34% of the total fatty acids was isolated and the isomers determined. Isomers found werecis-9-hexadecenoic acid,cis-9-octadecenoic acid,cis-11-octadecenoic acid,cis-9-eicosenoic acid,cis-11-eicosenoic acid,cis-11-docosenoic acid, andcis-13-docosenoic acid. Division of Industrial Research, U.S. Fish and Wildlife Service, Department of the Interior.     

Essential fatty acid contents of various fats: Interpretations of values by physico-chemical tests

Biological assays of oil and fat products, free from isomers of the naturally-occurringcis-9,cis-12 linoleic acid, have been shown to provide estimates of essential fatty acid content which agree well with values obtained by spectrophoto-metric analysis. However, when partially hydrogenated fats, such as those used in margarines, are bio-assayed the estimates obtained are only about 60% of those derived by spectro-photometric tests. In a blended corn oil margarine, good agreement was obtained for linoleic acid content by using biological assay or spectrophotometry, thio-cyanometric procedure, column chromatography for saturates plus iodine value, and gas liquid partition (GLP) chromatography. This margarine fat contained about 29% of the essential form of linoleic acid, and had a ratio to saturated fatty acids of 1.6:1. The hydrogenated corn oil margarine is unlike conventional margarines in providing high amounts of the isomeric forms of linoleic acid which lack essential fatty acid activity. For this reason, poor agreement was obtained between biological assay results and those by physico-chemical measurements of linoleic acid content. Such fat contains only about 6% of the essential form of linoleic acid, with a ratio to saturated fatty acids of ca. 0.3.1. From this study it is now possible to characterize, even without bio-assay data, the fatty acid composition of a highly isomerized fat, such as is found in hydrogenated corn oil margarine. The characterization groups the fatty acids into saturates and total linoleic acids, with the latter including estimates of the positional isomers of linoleic acid with widely spaced double bonds,trans forms of linoleic acid with methylene-in-terrupted double bonds, linoleic acids with the double bonds in conjugated position, andcis-9,cis-12 linoleic acid. The combined use of the spectrophotometric and thiocyanometric procedures makes it possible to estimate the essential fatty acid content of hydrogenated fats containing residual dienes.     

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.     

First Investigation in the Biochemical Analysis of the Invasive Crab <Emphasis Type="Italic">Portunus segnis</Emphasis> from Tunisian Waters

The invasive Portunus segnis, an atlantic species, was recently recorded in Tunisian waters. Since its record in the Gulf of Gabes, no studies have been carried out about the biochemical analysis of this alien species. In this context, our study aims to evaluate the fatty acid profile, lipid classes (neutral and polar), and nutritional value of breast of this invasive species. Specimens sampled from the gulf of Gabes were found to be rich in protein and oil, with significant differences between sexes. The level of saturated, monounsaturated, and polyunsaturated fatty acids in neutral and polar showed a significant difference between sexes. Saturated fatty acids were significantly higher in male P. segnis compared to the female. Docosahexaenoic (DHA), eicosapentaenoic (EPA), and arachidonic (ARA) were the most predominate polyunsaturated fatty acids (PUFA) in all oil classes. Oleic (C18:1) and Palmitoleic (C16:1) were the most abundant in monounsaturated. Palmitic (C16:0) and Stearic (C18:0) were the major saturated fatty acids. Consequently, the breast of P. segnis was a valuable source of high oil quality: It is rich in essential fatty acids and has an important n-3/n-6 ratio in both male and female blue crab. Therefore, the atherogenicity and the thrombogenicity were also evaluated, showing that P. segnis is a shellfish of greater value for human consumption in Tunisia.     

Lipid composition of selected margarines

Results of analytical studies on the composition of 10 selected margarines representative of consumeravailable hard and soft types are presented. Paired hard and soft products from the same manufacturer were chosen where possible. All of the margarines were compared on the basis of total fatty acid composition, polyunsaturated to saturated fatty acid ratios, totaltrans and thetrans content of the monoene and diene fractions, location of the double bond in the monoene isomers, per cent conjugation, distribution of the fatty acids at the 2 position of the triglycerides, tocopherol content, and the ratios of α-tocopherol to polyunsaturated fatty acids. As expected the soft margarines contained more polyunsaturated fatty acids than their companion hard types, but all soft margarines did not contain more polyunsaturated fatty acids than all of the hard margarines. The one margarine containing safflower oil had the highest polyunsaturated to saturated ratio. Eight of the ten margarines contained more than 15%trans monoene and nine contained less than 5%trans diene. Positional isomers in the monoene fraction were Δ6 toΔ12 with thecis Δ9 isomer predominating. All of the margarines contained less than 1.9% conjugation. The percentage oftrans monoene at the 2 position was greater for some margarines than that in the total fatty acid. This was attributed to the preferential placement of polyunsaturated fatty acids at the 2 position in the original vegetable oils. The forms of tocopherol found were characteristic of the original vegetable oils. Ratios of α-tocopherol to PUFA varied from 0.1 to 0.5 mg/g. Determination of the relationship of the amount of tocopherol content to either source or hardness is not possible on the basis of our data.     

Different metabolism of saturated and unsaturated long chain plasma free fatty acids by intestinal mucosa of rats

During fat absorption, unsaturated long chain fatty acids are esterified at a higher rate than saturated fatty acids of similar chain length. This phenomenon has been attributed to differences in the binding affinity of fatty acids to a cytosolic fatty acid-binding protein. As intestinal mucosa utilizes plasma free fatty acids as well, we investigated whether long chainplasma free fatty acids of different degree of saturation are metabolized also at different rates.³H-Palmitic and¹⁴C-linoleic acid complexed to rat serum were injected rapidly into a tail vein of fasting rats. One, 2 and 4 min later there was no difference between³H and¹⁴C-radioactivity in intestinal mucosa, suggesting equal initial uptake of the two labeled fatty acids from plasma. Despite their equal uptake, the incorporation of the isotopes into ester lipids was significantly different, however: at 2 min, 53.1±3.9% of³H and 73.8±4.6% of¹⁴C were recovered in ester lipids. Phospholipids and triglycerides accounted for most of the mucosal³H and¹⁴C. At 4 min, a similar distribution of isotopes in intestinal mucosal metabolites was found. These data show that despite equal initial uptake by intestinal mucosa unsaturated long chain fatty acids taken up from plasma are esterified to a higher and oxidized to a lower extent than saturated plasma free fatty acids. Unsaturated plasma free fatty acids, therefore, may provide a more important source of fatty acids for endogenous intestinal lipoprotein lipids than saturated plasma free fatty acids. It is speculated that the fatty acid binding protein might be operative not only in the intracellular transport and metabolism of luminal fatty acids but of plasma free fatty acids as well.     

Trans fatty acids in margarines marketed in Brazil: Content,labeling regulations and consumer information

A set of 46 different trademarks of margarines produced in Brazil by eight different companies was investigated in terms of the national labeling requirements for trans fatty acids (TFA). Experimental measurements of the content of total saturated fatty acids, cis‐monounsaturated fatty acids, cis‐polyunsaturated fatty acids and total TFA by gas chromatography showed the reliability of the data listed on the nutrition facts panel, which were used as reference for this analysis. The results revealed that 50% of the manufacturers and 13% of all the investigated trademarks of margarines violated the current Brazilian labeling regulations. A group of 200 consumers categorized by age, sex and years of formal education was also questioned about the importance of nutrition labeling information and TFA. Approximately 33% of the consumers interviewed were not informed about the possible detrimental effects of TFA on human health. Individuals with longer years of formal education and those affected by coronary heart diseases attributed to the intake of TFA were most interested in reading the nutrition labeling.     

Effects of oxidative stress on glycerolipid acyl turnover in rat hepatocytes

Lipid peroxidation was induced in freshly isolated rat hepatocytes by incubation in the presence of Fe³⁺, resulting in accumulation of thiobarbituric acid reactive substances. Analysis of lipid classes revealed that the levels and fatty acid compositions of the two major phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), remained unchanged but the levels of triacylglycerols (TAG) were significantly reduced, and some of their polyunsaturated fatty acids were selectively lost as the result of oxidant treatment. Acyl turnover in PC and PE as determined by ¹⁸O incorporation from H₂ ¹⁸O-containing media remained largely unchanged during oxidant treatment, while some increased turnover of the saturated fatty acids in TAG was observed. We hypothesize that constitutive recycling of membrane phospholipids rather than selective in situ repair eliminates peroxidized species of PC and PE, TAG could serve as an expendable fatty acid reserve, providing a limited but very dynamic pool of polyunsaturated fatty acids for the resynthesis of phospholipids.     

Dietary fat and the fatty acid composition of tissue lipids

Some characteristics of the fatty acid composition of animal tissue lipids are described and the origins of tissue fatty acids are discussed briefly. The effect of dietary fat on composition of tissue lipids is discussed. Types of dietary fatty acids for which experimental work is described include polyunsaturated fatty acids, short-chain fatty acids, fatty acids with chain length greater than C₁₈,trans unsaturated fatty acids, fatty acids with conjugated double bonds, acetylenic fatty acids, branched-chain fatty acids and oxygenated fatty acids. The individuality of fatty acids is discussed in relation to their roles as components of tissue lipids.     

Monitoring of Fat Content,Free Fatty Acid and Fatty Acid Profile Including <Emphasis Type="Italic">trans</Emphasis> Fat in Pakistani Biscuits

The fat contents of 12 brands of biscuits were extracted and evaluated for free fatty acids (FFA) and their fatty acid composition (FAC). The oil content and FFA varied from 13.7 to 27.6% and 0.2 to 1.0%, respectively. The FAC was analyzed by gas chromatography–mass spectroscopy with particular emphasis on trans fatty acids (TFA). Total saturated, unsaturated, cis-monounsaturated and polyunsaturated fatty acids were determined in the range of 37.9–46.9, 53.0–62.0, 12.3–43.7 and 0.1–9.2%, respectively. The high amount of TFA was observed in all biscuit samples and varied from 9.3 to 34.9%. The quantity and quality of the lipid fraction of the biscuits indicated that the all analyzed biscuits are a rich source of fat, saturated fatty acids and trans fatty acids, consequently not suitable for the health of consumers. The high content of trans fatty acids and palmitic acid also indicated that blends of RBD palm oil and partially hydrogenated oil had been used in the biscuit manufacturing.     

Production of branched-chain fatty acids from sterculia oil

Methyl sterculate was rearranged by use of 0.5% of rhodium catalyst to isomeric conjugated diene fatty acid methyl esters containing both methylene-and methyl-branched isomers. The rearanged products were hydrogenated directly to saturated, methyl-substituted, branched-chain fatty acid methyl esters with the methyl substituent at one of the positions formerly occupied by the cyclopropenoid ring. The crude branched-chain fatty acids from these esters were purified by recrystallization from a mixed solvent of ethanol and water (80:20, v/v) and flash distillation; the product contained about 90% of branched-chain fatty acids (C₁₉:80%, C₁₈:10%). Esters of the branched-chain fatty acid were prepared with 2-ethylhexyl alcohol or trimethylolpropane, and the characteristic properties of these esters were investigated. The branched-chain fatty esters appear to have potential utility in lubricants; other uses may be possible. Presented at the AOCS meeting in New Orleans, May 1981.