Comparison of Lipoprotein Cholesterol Levels in Golden Syrian Hamster Administrated trans-Octadecenoic Acid Positional Isomers.

We previously conducted a study using HepG2 cells to compare the effect on the secreted apolipoprotein B-100 and apolipoprotein A-1 ratio (B-100/A-1) corresponding to the ratio of low-density to high-density lipoprotein cholesterol (LDL/HDL) among 13 types of trans-octadecenoic acid (t-18:1) positional isomers. The results revealed that trans-5-18:1 (t5) significantly increased B-100/A-1. In this study, 1% of t5 in the diet, corresponding to 2.

Simultaneous Separation of Triacylglycerol Enantiomers and Positional Isomers by Chiral High Performance Liquid Chromatography Coupled with Mass Spectrometry.

The rapid and simultaneous separation of triacylglycerol (TAG) enantiomers and positional isomers was achieved using chiral high performance liquid chromatography (HPLC). TAGs composed of two fatty acids, which were both saturated (P: palmitic acid or S: stearic acid) and unsaturated (O: oleic acid or L: linoleic acid; e.g.

Evaluating the Content and Distribution of Trans Fatty Acid Isomers in Foods Consumed in Japan.

Trans fatty acids (TFA) are considered risk factors for cardiovascular disease. However, detailed information on total content of TFA and TFA isomers and distribution of trans-octadecenoic acid positional isomers in foods consumed in Japan is not available till date. In this study, 250 foods, 169 processed foods and 81 foods derived from ruminant meat or milk, were analyzed.

Study of Trans Fatty Acid Formation in Oil by Heating Using Model Compounds.

The intake of trans fatty acids (TFAs) in foods changes the ratio of low density lipoprotein (LDL) to high density lipoprotein (HDL) cholesterol in blood, which causes cardiovascular disease. TFAs are formed by trans isomerization of unsaturated fatty acids (UFAs). The most recognized formation mechanisms of TFAs are hydrogenation of liquid oil to form partially hydrogenated oil (PHO,) and biohydrogenation of UFAs to form TFA in ruminants.

Comparison of the Effect of trans Fatty Acid Isomers on Apolipoprotein A1 and B Secretion in HepG2 Cells.

Intake of trans fatty acid (TFA) is believed to change the ratio of low-density lipoprotein (LDL) to high density lipoprotein (HDL) cholesterol in blood, which leads to cardiovascular disease. In this study, thirteen types of TFA including monoene type TFA (trans-octadecenoic fatty acid isomers, t-18:1 isomers), diene type TFA (t9,t12-18:2), and triene type TFA (t-18:3) were added to cultured HepG2 cells to compare the amount of apolipoprotein A1 and B (those relating to levels of HDL and LDL cholesterol in blood, respectively) being secreted. We found that trans-5-18:1 increased the secretion of apolipoprotein B relative to oleic acid (cis-9-18:1, control).

Comparison of Catabolic Rates of sn-1, sn-2, and sn-3 Fatty Acids in Triacylglycerols Using CO Breath Test in Mice.

Fatty acids in triacylglycerols (TAGs) are catabolized after digestion. However, the catabolic rates of the fatty acids at the sn-1, sn-2, and sn-3 positions of TAGs have not been compared. To elucidate the differences, we studied the catabolic rates of C-labeled palmitic acid, oleic acid, and capric acid at the sn-1, sn-2, or sn-3 position of TAGs using isotope-ratio mass spectrometry.

Quantification of Triacylglycerol Positional Isomers in Rat Milk.

The absolute amount of triacylglycerol (TAG) positional isomers was analyzed in rat milk fat, a representative of non-ruminant milk fat, using a HPLC-UV-atmospheric pressure chemical ionization-MS/MS system equipped with an octacosyl silylation column or polymeric ODS column. TAGs consisting of two oleic acids (O) and one palmitic acid (P) were the most abundant. In particular, β-OPO, a TAG binding P at the β-position (sn-2) and two Os at the α-positions (sn-1/3), was prominent.

Trans-octadecenoic Acid Positional Isomers Have Different Accumulation and Catabolism Properties in Mice.

Trans fatty acids (TFA) are considered risk factors for cardiovascular disease (CVD), while the details of distribution and metabolism of the individual isomers are not clear. Here we investigated the accumulation and catabolic rate of TFA positional isomers of octadecenoic acid (18:1) in mice. ICR mice were fed deuterium- and [1-(13)C] stable isotope-labeled trans-9-18:1 (9t-18:1*), trans-10-18:1 (10t-18:1*), or trans-11-18:1 (11t-18:1*) for 2 or 4 weeks, or a TFA mixture (9t-18:1*, 10t-18:1*, and 11t-18:1*) for 3 weeks.

Abundances of Triacylglycerol Positional Isomers and Enantiomers Comprised of a Dipalmitoylglycerol Backbone and Short- or Medium-chain Fatty Acids in Bovine Milk Fat.

Bovine milk fat (BMF) is composed of triacylglycerols (TAG) rich in palmitic acid (P), oleic acid (O), and short-chain or medium-chain fatty acids (SCFAs or MCFAs). The composition and binding positions of the fatty acids on the glycerol backbone determine their physical and nutritional properties. SCFAs and MCFAs are known to characteristically bind to the sn-3 position of the TAGs in BMF; however, there are very few non-destructive analyses of TAG enantiomers binding the fatty acids at this position.

Generation of Tetracosahexaenoic Acid in Benthic Marine Organisms.

Tetracosahexaenoic acid (THA, 24:6n-3) has been shown to have the strongest ability to suppress accumulation of lipids in HepG2 cells among well-known n-3 highly unsaturated fatty acids, such as EPA and DHA. In this study, a method for mass production of THA was investigated using distributions of THA and DHA in thirty-two marine organisms, such as starfishes, right-eyed flounders, shellfishes, and sharks. The fatty acid composition of the marine organisms was analyzed using GC-FID and THA was detected in starfish, right-eyed flounder, and shark.

Regiospecific Distribution of trans-Octadecenoic Acid Positional Isomers in Triacylglycerols of Partially Hydrogenated Vegetable Oil and Ruminant Fat.

It is revealed that binding position of fatty acid in triacylglycerol (TAG) deeply relates to the expression of its function. Therefore, we investigated the binding positions of individual trans-octadecenoic acid (trans-C18:1) positional isomers, known as unhealthy fatty acids, on TAG in partially hydrogenated canola oil (PHCO), milk fat (MF), and beef tallow (BT). The analysis was carried out by the sn-1(3)-selective transesterification of Candida antarctica Lipase B and by using a highly polar ionic liquid capillary column for gas chromatography-flame ionization detection.

Differential effects of triacylglycerol positional isomers containing n-3 series highly unsaturated fatty acids on lipid metabolism in C57BL/6J mice.

The present study investigated the effects of binding position of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to triacylglycerol (TAG) on lipid metabolism in C57BL/6J mice. Mice were treated with pure TAG positional isomers, including 1,2(2,3)-dipalmitoyl-3(1)-eicosapentaenoyl glycerol, 1,3-dipalmitoyl-2-eicosapentaenoyl glycerol, 1,2(2,3)-dipalmitoyl-3(1)-docosahexaenoyl glycerol, and 1,3-dipalmitoyl-2-docosahexaenoyl glycerol. Compared to DHA bound to the α-position of TAG, DHA bound to the β-position more effectively inhibited fatty acid synthetic enzymes and cholesterol-metabolism enzymes and thus reduced TAG and cholesterol concentrations in the serum and liver.

Comparison of the lipid-lowering effects of four different n-3 highly unsaturated fatty acids in HepG2 cells.

The effects on lipid metabolism of four different n-3 highly unsaturated fatty acids (n-3HUFA) including eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3), docosahexaenoic acid (DHA, 22:6n-3), and tetracosahexaenoic acid (THA, 24:6n-3) were compared in the HepG2 cell model. None of the n-3HUFAs affected the viability of the cells. THA exerted the strongest suppression on the synthesis of triacylglycerol and cholesteryl ester (ChE), and the order of the strength of suppression was found to be THA > DHA > DPA > EPA.

Characterization of cis- and trans-octadecenoic acid positional isomers in edible fat and oil using gas chromatography-flame ionisation detector equipped with highly polar ionic liquid capillary column.

In this study, the characterisation of all cis- and trans-octadecenoic acid (C18:1) positional isomers in partially hydrogenated vegetable oil (PHVO) and milk fat, which contain several cis- and trans-C18:1 positional isomers, was achieved by gas chromatography-flame ionisation detector equipped with a highly polar ionic liquid capillary column (SLB-IL111). Prior to analysis, the cis- and trans-C18:1 fractions in PHVO and milk fat were separated using a silver-ion cartridge. The resolution of all cis-C18:1 positional isomers was successfully accomplished at the optimal isothermal column temperature of 120 °C.

Effect of pressure on the selectivity of polymeric C18 and C30 stationary phases in reversed-phase liquid chromatography. Increased separation of isomeric fatty acid methyl esters, triacylglycerols, and tocopherols at high pressure.

A high-density, polymeric C18 stationary phase (Inertsil ODS-P) or a polymeric C30 phase (Inertsil C30) provided improved resolution of the isomeric fatty acids (FAs), FA methyl esters (FAMEs), triacylglycerols (TAGs), and tocopherols with an increase in pressure of 20-70MPa in reversed-phase HPLC. With respect to isomeric C18 FAMEs with one cis-double bond, ODS-P phase was effective for recognizing the position of a double bond among petroselinic (methyl 6Z-octadecenoate), oleic (methyl 9Z-octadecenoate), and cis-vaccenic (methyl 11Z-octadecenoate), especially at high pressure, but the differentiation between oleic and cis-vaccenic was not achieved by C30 phase regardless of the pressure. A monomeric C18 phase (InertSustain C18) was not effective for recognizing the position of the double bond in monounsaturated FAME, while the separation of cis- and trans-isomers was achieved by any of the stationary phases.

Actual ratios of triacylglycerol positional isomers and enantiomers comprising saturated fatty acids and highly unsaturated fatty acids in fishes and marine mammals.

It has been previously shown that the positional isomers of triacylglycerol (TAG) containing palmitic acid (P) and highly unsaturated fatty acids (HUFAs) such as DHA (D) and EPA (E) vary between fishes and marine mammals. However, it has not yet been understood why in marine mammals HUFAs are located only at the α position when two palmitic acid chains combine, and not in fishes. In order to gain further understanding of the biosynthetic pathways involved in the formation of these asymmetric TAGs, we investigated whether the HUFA in the TAG of marine mammals exists predominantly at the sn-1 or sn-3 position.

Quantification of triacylglycerol molecular species in cocoa butter using high-performance liquid chromatography equipped with nano quantity analyte detector.

Triacylglycerol (TAG) molecular species were quantified through high-performance liquid chromatography (HPLC) equipped with a nano quantity analyte detector (NQAD). TAG standard compounds, i.e.

Resolution behavior of cis- and trans-octadecenoic acid isomers by AOCS official method using SP-2560 column.

The gas chromatography-flame ionization detector equipped with a higher polarity column (i.e., SP-2560) has often been used for the quantification of trans-fatty acids in food.

Simple method for the quantification of milk fat content in foods by LC-APCI-MS/MS using 1,2-dipalmitoyl-3-butyroyl-glycerol as an indicator.

We have developed a simple method for the quantification of milk fat in foods using 1,2-dipalmitoyl-3-butyroyl-glycerol (PPBu) as an indicator of milk fat content by high-performance liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry. The separation of the triacylglycerol positional isomer, 1,3-dipalmitoyl-2-butyroyl-glycerol (PBuP) and PPBu, was achieved using an octacocyl silylation (C28) column, and multiple reaction monitoring was employed. The milk fat contents in butter, butter-blended margarine, and butter cookies were quantified using two different sample preparation methods.

Actual ratio of triacylglycerol positional isomers in milk and cheese.

Actual ratios of triacylglycerol (TAG) positional isomers in human, rat, and cow milk fat and cow, buffalo, goat, and sheep cheese fat were analyzed using HPLC-UV-atmospheric pressure chemical ionization-MS/MS system equipped with an octacosyl silylation column or polymeric ODS column. We substituted cheese fats for milk fats in parts of our study because milks from ruminants, with the exception of cows, are difficult to get in Japan. The actual ratio of β-PPC (the TAG consisting of two palmitic acids (P) and one capric acid (C), with the palmitic acid located at the β position) and β-PCP in human milk was different from those in ruminants, with more than half of the medium-chain fatty acids located at the β position even though other fats possessed it mainly at the α position.

Actual ratios of triacylglycerol positional isomers consisting of saturated and highly unsaturated fatty acids in fishes and marine mammals.

The distribution of fatty acid species at the (sn-1, 3) position or the (sn-2) position of triacylglycerol (TAG) in natural fats and oils has already been analysed by many researchers and several interesting results have been reported. However, most of these reports only focused on the distribution of fatty acids at the or positions in TAG, and did not take account of the combination of fatty acids in the TAG, i.e.

Rapid separation of triacylglycerol positional isomers binding two saturated Fatty acids using octacocyl silylation column.

The rapid separation of a triacylglycerol positional isomer (TAG-PI) pair was examined via high-performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry using an octacocyl silylation (C28) column. A TAG-PI pair binding two palmitic acids and one fatty acid that structurally differs from palmitic acid was separated at 10°C and 15°C using acetone as the mobile phase. However, the TAG-PI pair binding two unsaturated fatty acids and one saturated fatty acid was not separated by the C28 column.

Enantiomeric separation of asymmetric triacylglycerol by recycle high-performance liquid chromatography with chiral column.

In our previous studies, we employed recycle HPLC for the separation of triacylglycerol (TAG)-positional isomers (PIs). In this study, a recycle HPLC system equipped with a polysaccharide-based chiral column was applied to the enantiomeric separation of some asymmetric TAGs having straight-chain C16-C18 acyl residues. As a result, 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (rac-PPO), 1,2-dioleoyl-3-palmitoyl-rac-glycerol (rac-OOP), and 1,2-dipalmitoyl-3-linoleoyl-rac-glycerol (rac-PPL) were resolved into their respective enantiomers.

Highly unsaturated fatty acid might act as an antioxidant in emulsion system oxidized by azo compound.

Now it is recognized that DHA is oxidatively stable fatty acid compared with linoleic acid (LA) in emulsified system, although DHA is oxidatively unstable in a bulk system. In fact, an emulsified mixture of DHA and LA behaves as in a bulk system, namely the oxidative stability of DHA becomes lower than that of LA. Therefore, in this study, tridocosahexaenoate (DDD) and glycerol trilinoleate (LLL) were separately emulsified using TritonX-100 as an emulsifier and DDD emulsion was mixed with the oxidizing LLL emulsion using a water-soluble radical initiator, 2,2'-azobis(2-aminopropane) dihydrochloride.

Characterization of non-endcapped polymeric ODS column for the separation of triacylglycerol positional isomers.

The characteristics of a non-endcapped polymeric ODS column for the resolution of triacylglycerol positional isomers (TAG-PI) were examined using a recycle HPLC-atmospheric pressure chemical ionization/mass spectrometry system. A pair of TAG-PI containing saturated fatty acids at least 12 carbons was separated. Except for TAG-PI containing elaidic acid, pairs of TAG-PI containing three unsaturated fatty acids were not separated, even by recycle runs.