bluuebunny/crossref_metadata_2025 huggingface dataset:
Heneicosapentaenoate (21:5n−3): Its incorporation into lipids and its effects on arachidonic acid and eicosanoid synthesis
Authors: Larsen L. N. , Høvik K. , Bremer J. , Holm K. H. , Myhren F. , Børretzen B.
Published: November 2006

6,9,12,15,18‐Heneicosapentaenoic acid (21:5n‐3) (HPA), present in small amounts in fish oils, has been prepared by chemical elongation of eicosapentaenoic acid (EPA) and its biological properties compared with EPA and docosahexaenoic acid (DHA). All the double bonds of HPA are displaced one carbon away from the carboxyl group when compared to EPA. HPA is incorporated into phospholipids and into triacylglycerol in cell culture to a similar extent as EPA and DHA. HPA is a stronger inhibitor of the conversion of α‐linoleic acid and dihomo‐γ‐linolenic acid to arachidonic acid (AA) in hepatoma cells than are EPA, DHA, and AA. HPA is a poor substrate for prostaglandin H synthase and for 5‐lipoxygenase, but it inactivates prostaglandin H synthase as rapidly as do AA, EPA, and DHA. HPA inhibits thromboxane synthesis in isolated platelets as efficiently as EPA. EPA, HPA, and DHA are all weak inducers of acyl‐CoA oxidase in hepatoma cells. Therefore, since fish oils contain only small amounts of HPA, it is unlikely that this fatty acid is of particular significance for the biological effects of these oils, possibly with the exception that it is a strong inhibitor of AA synthesis.
Characterization of an HL‐60 cell variant resistant to the antineoplastic ether lipid 1‐O‐octadecyl‐2‐o‐methyl‐rac‐glycero‐3‐phosphocholine
Authors: Small George W. , Strum Jay C. , Daniel Larry W.
Published: November 2006

A resistant cell line (HL‐60R) was selected by incubating HL‐60 cells with increasing concentrations of 1‐O‐octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine (ET‐18‐OCH3) and used to examine the mechanism of resistance to the antineoplastic ether‐linked lipid. The HL‐60R cells exhibited a>10‐fold increase in resistance when measured by [3H]‐thymidine incorporation in comparison to the HL‐60 cell line. ET‐18‐OCH3 binding occurred at 4°C and was not saturable at the concentrations tested (1–100 μM), indicating that the binding was receptor‐independent. At 4°C, association of ET‐18‐OCH3 was low for each cell line. At 37°C, uptake in the HL‐60 cells was approximately 5‐fold greater in comparison to HL‐60R cells at each concentration tested. However, when the cellular content of ET‐18‐OCH3 was equal, both cell lines experienced similar declines in cell growth. Cellular incorporation of ether lipid was determined using serum‐free media and in the presence of serum albumin or lipoproteins. Reduced uptake by the resistant cell line was observed only in the presence of albumin. A greater proportion of ether lipid could be removed from prelabeled HL‐60R cells than from HL‐60 cells, by an albumin wash procedure, indicating an increased rate of internalization and retention by the sensitive cell line. ET‐18‐OCH3 uptake in the HL‐60 cell line was also more sensitive to treatment with endocytic (chloroquine, monensin) or metabolic (NaF, KCN) inhibitors. These results suggest that uptake is the principal determinant influencing sensitivity of the resistant cell line and consists of receptor‐independent binding followed by internalization. Differential uptake requires the presence of serum albumin and is dependent on the energy‐dependent endocytosis of the ether lipid.
Conjugated linoleic acid modulation of phorbol ester‐induced events in murine keratinocytes
Authors: Liu Kai‐Li , Belury Martha A.
Published: November 2006

Recent work in our lab has shown that the chemoprotective fatty acid, conjugated linoleic acid (CLA), inhibits phorbol ester skin tumor promotion in mice. Because little is known about the deposition of CLA into tissues as well as its biological activity, this study compared the incorporation and biological activity of CLA to linoleic acid (LA; 18:2, c9, c12) and arachidonic acid (AA; 20:4 c5, c8, c11, c14) in cultured keratinocytes. When keratinocytes (HEL‐30) were grown in media containing 14C‐CLA for various periods, more than 50% of the 14C‐CLA was incorporated into cellular lipids by 9 h. The distribution of CLA in phospholipid classes was similar to LA. Approximately 50% of 14C‐LA and 14C‐CLA were incorporated into phosphatidylcholine (PC), while the remainder was taken up by phosphatidylethanolamine (PE) and phosphatidyl‐serine/phosphatidylinositol (PS/PI). In contrast, 14C‐AA was more equitably distributed into PC, PE, or PS/PI (27, 30, or 38%, respectively). When keratinocytes were prelabeled with radiolabeled fatty acids, phorbol ester‐induced release of 14C‐CLA was 1.5 times higher than 14C‐LA and 14C‐AA. However, 14C‐prostaglandin E (PGE) release in 14C‐CLA prelabeled cultures was 6 and 13 times lower than cultures treated with 14C‐LA and 14C‐AA, respectively. Moreover, the ability of nonradiolabeled CLA to support ornithine decarboxylase activity, a hallmark event of tumor promotion, was significantly lower than in LA‐ and AA‐treated cultures. These studies suggest that CLA inhibits skin tumor promotion, in part, through a PGE‐de‐pendent mechanism.
Unusual effects of some vegetable oils on the survival time of stroke‐prone spontaneously hypertensive rats
Authors: Huang Min‐Zhao , Watanabe Shiro , Kobayashi Tetsuyuki , Nagatsu Akito , Sakakibara Jinsaku , Okuyama Harumi
Published: November 2006

Preliminary experiments have shown that a diet containing 10% rapeseed oil (low‐erucic acid) markedly shortens the survival time of stroke‐prone spontaneously hypertensive (SHRSP) rats under 1% NaCl loading as compared with diets containing perilla oil or soybean oil. High‐oleate safflower oil and high‐oleate sunflower oil were found to have survival time‐shortening activities comparable to that of rapeseed oil; olive oil had slightly less activity. A mixture was made of soybean oil, perilla oil, and triolein partially purified from high‐oleate sunflower oil to adjust the fatty acid composition to that of rapeseed oil. The survival time of this triolein/mixed oil group was between those of the rapessed oil and soybean oil groups. When 1% NaCl was replaced with tap water, the survival time was prolonged by ∼80%. Under these conditions, the rapeseed oil and evening primrose oil shortened the survival time by ∼40% as compared with n‐3 fatty acid‐rich perilla and fish oil; lard, soybean oil, and safflower oil with relatively high n‐6/n‐3 ratios shortened the survival time by roughly 10%. The observed unusual survival time‐shortening activities of some vegetable oils (rapeseed, high‐oleate safflower, high‐oleate sunflower, olive, and evening primrose oil) may not be due to their unique fatty acid compositions, but these results suggest that these vegetable oils contain factor(s) which are detrimental to SHRSP rats.
γ‐linolenic acid‐containing diet attenuates bleomycin‐induced lung fibrosis in hamsters
Authors: Ziboh Vincent A. , Yun Monica , Hyde Dallas M. , Giri Shri N.
Published: November 2006

Although bleomycin (BLM), an antineoplastic drug, is used in the treatment of a variety of tumors, the mechanism(s) that contribute to its induced lung injury and fibrosis are not fully elucidated. Since alterations in the levels of certain fatty acid metabolites have been associated with BLM‐induced lung injury, we tested the effects of dietary γ‐linolenic acid (GLA)‐containing evening primrose oil on BLM‐induced morphological alterations in the hamster lung, the marked elevation of tissue hydroxyproline (a marker for collagen synthesis), and elevated generation of arachidonic acid metabolites (marker of inflammatory mediators). Our data revealed that after 14 d of dietary GLA‐containing oil (i) BLM‐induced elevation of lung hydroxyproline was suppressed (P<0.05), (ii) the marked BLM‐induced elevation of lung leukotriene B4 (LTB4) (a marker of polymorphonuclear generation of proinflammatory LTB4) was significantly suppressed (P<0.05). The decrease in LTB4 was accompanied by marked elevations (P<0.05) of lung prostaglandin E1 (PGE1) and 15‐hydroxyeicosatrienoic acid (15‐HETrE), both with known antiinflammatory properties. Taken together, data from these studies suggest that dietary GLA‐containing oil contributes to tissue elevation of PGE1 and 15‐HETrE, which in vivo may attenuate lung inflammation and fibrosis.
Oleanolic acid and ursolic acid stabilize liposomal membranes
Authors: Han Suk Kyu , Ko Young Ill , Park Soo Jung , Jin In Jung , Kim Young Mi
Published: November 2006

The effects of oleanolic acid (OA) and ursolic acid (UA) on the fluidity and stability of dipalmitoyl phosphatidylcholine (DPPC) liposomal membrane were monitored by measuring the fluorescence polarization of 1,6‐diphenyl‐1,3,5‐hexatriene labeled in the liposomal membrane and the leakage of calcein from the probe‐encapsulated liposomes. The experiments with the liposomes made of DPPC and OA or UA showed that OA and UA exhibited a moderate fluidity‐modulating effect for the liquid‐crystalline liposomal membrane, and a strong condensing effect for both crystalline and liquid‐crystalline liposomal membranes. Their effects were comparable to those of cholesterol. These results suggest that their fluidity‐modulating and condensing effects might have some implications in their biological functions.
Structural characterization of a “Signature” phosphatidylethanolamine as the major 10‐hydroxy stearic acid‐containing lipid of Cryptosporidium parvum oocysts
Authors: Schrum David P. , Alugupalli Srinivas , Kelly Sean T. , White David C. , Fayer Ronald
Published: November 2006

A 10‐hydroxy stearic acid‐containing lipid from Cryptosporidium parvum was purified by thin‐layer chromatography and analyzed by infrared spectroscopy, fast‐atom bombardment mass spectrometry, 1H and 31P nuclear magnetic resonance spectroscopy, and was identified as phosphatidylethanolamine.
Capillary supercritical fluid chromatography‐atmospheric pressure chemical ionization mass spectrometry of γ‐ and α‐linolenic acid containing triacylglycerols in berry oils
Authors: Manninen Pekka , Laakso Päivi
Published: November 2006

The effect of the γ‐linolenic acid (18:3n‐6) residue on the elution of triacylglycerols on a 25% cyanopropyl‐25% phenyl‐50% methylpolysiloxane stationary phase was confirmed by using capillary supercritical fluid chromatography‐atmospheric pressure chemical ionization mass spectrometry [cSFC‐(APCI)MS]. The general elution rule on this stationary phase is that triacylglycerols having the same ACN+2n value coeluted (ACN‐acyl carbon number and n=combined number of double bonds in the acyl chains). The different effect of γ‐ and α‐linolenic acid residues on the retention of triacylglycerols and the use of cSFC‐(APCI)MS allowed the study of the number of different linolenic acid residue isomer combinations in triacylglycerols with an identical ACN and degree of unsaturation. Stearidonic acid (18:4n‐3) residue was found to have a similar effect on the retention behavior of triacylglycerols as that of γ‐linolenic acid residue. The abundance of the [M‐RCOO]+ ion, formed by the loss of one fatty acid moiety of a triacylglycerol, was found to be clearly higher in the case of γ‐isomer of the linolenic acid than that of α‐isomer in the identical regiospecific position. This indicates that the distance of the double bonds from the glycerol backbone in the acyl chain affects the stability of a triacylglycerol molecule in the (APCI)MS system. The triacylglycerol composition and the fatty acid combinations of triacylglycerols were found to be almost identical in black currant (Ribes nigrum) and alpine currant (R. alpinum) seed oils.
Correlation of suppressed linoleic acid metabolism with the hypocholesterolemic action of eritadenine in rats
Authors: Sugiyama Kimio , Yamakawa Akihiro , Saeki Shigeru
Published: November 2006

The dose‐dependent effects of dietary eritadenine on the metabolism of linoleic acid and on the plasma cholesterol concentration were investigated to clarify the mechanism of the hypocholesterolemic action of eritadenine in rats. Rats were fed control or eritadenine‐supplemented (2 to 20 mg/kg) diets for 14 d. Eritadenine supplementation significantly decreased both the plasma cholesterol concentration and the 20∶4n−6/18∶2n−6 ratio of liver microsomal and plasma phosphatidylcholine (PC) in a dose‐dependent manner. Eritadenine was also found to decrease the activity of Δ6 desaturase in liver microsomes; these was significant correlation between the Δ6‐desaturase activity and the 20∶4n−6/18∶2n−6 ratio in the PC of liver microsomes (r=0.989, P<0.001) or plasma (r=0.986, P<0.001). Certain plasma PC molecular species, as represented by 16:0‐18:2, were increased by eritadenine in a dose‐dependent manner, and certain plasma PC molecular species, as represented by 18:0‐20:4, were conversely decreased by eritadenine. There was a significant correlation between the plasma total cholesterol concentration and the proportion of the sum of plasma PC molecular species which contain 18:1 or 18:2 in the sn‐2 position. These results support the idea that the suppression of linoleic acid metabolism by eritadenine might be associated with the hypocholesterolemic action of eritadenine.
Effect of trifluoperazine on certain arterial wall lipid‐metabolizing enzymes inducing atherosclerosis in rhesus monkeys
Authors: Mohindroo A. , Ahluwalia P.
Published: November 2006

The effect of trifluoperazine (TFP) was investigated on arterial wall lipid‐metabolizing enzymes like acyl‐CoA:cholesterol acyltransferase (ACAT) and cholesterol ester hydrolase (CEH) in rhesus monkeys. The activity was determined in aortic wall homogenates obtained from rhesus monkeys fed an atherogenic diet coupled with intramuscular injections of adrenaline and TFP. Although TFP had no significant effect on serum cholesterol and triglycerides, it decreased significantly the formation of atherosclerotic lesions by decreasing the esterification of cholesterol, by inhibiting ACAT and enhancing its utilization by activating CEH. Hence, the preventive effect of TFP on the development of atherosclerosis in rhesus monkeys is mediated through its ability to influence the activities of arterial wall lipid‐metabolizing enzymes like ACAT and CEH.
Facile and general method for preparation of (E)‐4‐hydroxy‐2‐alkenals
Authors: Sugamoto Kazuhiro , Matsushita Yoh‐ichi , Matsui Takanao
Published: November 2006

A facile one‐pot synthesis of (E)‐4‐hydroxy‐2‐alkenals such as (E)‐4‐hydroxy‐2‐nonenal, (E)‐4‐hydroxy‐2‐heptenal, and (E)‐4‐hydroxy‐2‐hexenal was achieved from the corresponding (2E,4E)‐2,4‐alkadienals by reduction‐oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethylphosphite.
Effects of oxidative stress on glycerolipid acyl turnover in rat hepatocytes
Authors: Girón‐Calle Julio , Schmid Patricia C. , Schmid Harald H. O.
Published: November 2006

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 H218O‐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.
The effects of cyclic fatty acid monomers on cultured porcine endothelial cells
Authors: Flickinger Brent D. , McCusker Robert H. , Perkins Edward G.
Published: November 2006

The popularity of polyunsaturated oils used in food applications and preparation continues to appreciate as a result of positive health claims. With polyunsaturated oils inherently more susceptible to oxidative and thermal degradation, the formation of new fatty acid species increases considerably. The presence of one species known as cyclic fatty acid monomers (CFAM) has been detected as a component of many oils subjected to various thermal processes including deep‐fat frying. The effect of CFAM on metabolic processes has not been fully characterized. In this study, confluent porcine aortic endothelial cells incorporated CFAM into their polar and nonpolar lipid fractions following a 48‐h exposure to 31 and 62 ppm CFAM in the culture medium. Subsequently, the influence of CFAM incorporation on various membrane‐dependent physical properties and biochemical processes was investigated. CFAM decreased the lipid packing order of the membrane bilayer core but did not alter the lipid packing order of lipid chain segments at or near the lipid‐water interface of the membrane. CFAM led to significant reductions in Ca2+ ATPase activity and monolayer integrity while eliciting a significant increase of prostacyclin synthesis and secretion.
Failure of the nonselective β‐blocker propranolol to affect lipoprotein lipase gene expression in the rat
Authors: Gouni‐Berthold I. , Oka K. , Berthold H. K. , Chan L.
Published: November 2006

Treatment with β‐blockers has been reported to be associated with the development of hypertriglyceridemia. The etiology, even the existence, of this phenomenon is controlverisal. The purpose of our study was to examine whether the nonselective β‐blocker propranolol causes hypertriglyceridemia in the rat and whether its action is mediated by the modulation of lipoprotein lipase (LPL) messenger RNA (mRNA) accumulation or activity. LPL activity was assayed in fresh tissue by incubation with tritiated triglycerides. LPL mRNA was quantified in total RNA by slot‐blot analysis using a mouse LPL complementary DNA probe. We have conducted three series of experiments in unanaesthetized rats in order to study the effects of different single doses of propranolol (1.5 to 6 mg i.p.) and different durations of treatment (15 min to 4 wk). We measured triglyceride and cholesterol levels in plasma as well as the LPL activity and mRNA levels in the heart and adipose tissue before and after propranolol administration. In these experiments we did not find any significant decrease in either the activity or the amount of mRNA of lipoprotein lipase nor was there any change in plasma lipids following treatment. Our results lead us to the conclusion that the nonselective β‐blocker propranolol affects neither the activity nor, the mRNA level of LPL in the rat.
Dietary sandalwood seed oil modifies fatty acid composition of mouse adipose tissue, brain, and liver
Authors: Liu Yandi , Longmore Robert B.
Published: November 2006

Sandalwood (Santalum spicatum) seed oil, which occurs to about 50% of the weight of the seed kernels, contains 30–35% of total fatty acids (FA) as ximenynic acid (XMYA). This study was designed to obtain basic information on changes in tissue FA composition and on the metabolic fate of XMYA in mice fed a sandalwood seed oil (SWSO)‐enriched diet. Female mice were randomly divided into three groups, each receiving different semisynthetic diets containing 5.2% (w/w) fat (standard laboratory diet), 15% canola oil, or 15% SWSO for 8 wk. The effects of SWSO as a dietary fat on the FA composition of adipose tissue, brain, and liver lipids were determined by analyses of FA methyl ester derivatives of extracted total lipid. The FA compositions of the liver and adipose tissue were markedly altered by the dietary fats, and mice fed on a SWSO‐enriched diet were found to contain XMYA but only in low concentration (0.3 3%) in these tissues; XMYA was not detected in brain. Oleic acid was suggested to be a principal XMYA biotransformation product. The results were interpreted to suggest that the metabolism of XMYA may involve both biohydrogenation and oxidation reactions.
The unusual occurrence of 14‐methylhexadecanoic acid in pinaceae seed oils among plants
Authors: Wolff Robert L. , Christie William W. , Coakley David
Published: November 2006

14‐Methylhexadecanoic (14‐MHD) acid has been identified in a sample of pine seed oil (Pinus contorta) by gas‐liquid chromatography‐mass spectrometry of its picolinyl ester derivative: Its identification (through its equivalent chain length) and its distribution in four conifer families have been checked. It occurred only in Pinaceae, where it was found in 72 species belonging to the genera Pinus, Abies, Cedrus, Tsuga, Pseudotsuga, Larix, and Picea, in the range 0.02–1.15%. 14‐MHD acid could not be detected in the lipids of Taxaceae (Taxus baccata), Cupressaceae (Juniperus communis), or Taxodiaceae (Sciadopytis verticillata), even after a 10‐fold concentration of the saturated acid fraction isolated by argentation thinlayer chromatography. It is concluded that Pinaceae, along with Ginkgo biloba seed lipids, are major exceptions in the plant kingdom with regard to 14‐MHD acid, which otherwise occurs almost exclusively in lipids of animals and microorganisms. The biosynthesis and metabolic role of 14‐MHD acid, which other‐wise also occur in wood and leaf lipids, remain unknown.
Analysis of oxylipins by high‐performance liquid chromatography with evaporative light‐scattering detection and particle beam‐mass spectrometry
Authors: Rehbock Bettina , Gansser Dietmar , Berger Ralf G.
Published: November 2006

The metabolism of 13 S‐hydroperoxy‐9Z,11E,15Z‐octadecatrienoic acid was investigated in a crude enzyme extract from mung bean seedlings (Phaseolus radiatus L.). Hydroperoxide‐metabolizing activity was mainly due to a hydroperoxide lyase and, to a lesser extent, to an allene oxide synthase and a peroxygenase. Oxylipins originating from hydrolysis and cyclization of the allene oxide synthase product 12,13‐epoxy‐9Z,11,15Z‐octadecatrienoic acid and from peroxygenase catalysis were identified by high‐performance liquid chromatography (HPLC) particle beam‐mass spectrometry (PB‐MS) and quantified by normal‐phase HPLC with an evaporative light‐scattering detector (ELSD). An advantage of this methodology was the possibility to avoid extensive derivatization procedures commonly used for the gas chromatographic analysis of oxylipins. Owing to a comparable sample inlet system, the ELSD served an important analytical pilot function for the PB‐MS: Qualitatively identical chromatographic patterns were obtained with both detection systems. The HPLC system enabled the separation of methyl 12‐oxo‐phytodienoate, methyl 11‐hydroxy‐12‐oxo‐9Z,15Z‐octadecadienoate, methyl 12‐oxo‐13‐hydroxy‐9Z,15Z‐octadecadienoate, methyl 9‐hydroxy‐12‐oxo‐10E,15Z‐octadecadienoate, methyl 13‐hydroxy‐9Z,11E,15Z‐octadecatrienoate, methyl 15,16‐epoxy‐13‐hydroxy‐9Z,11E,15Z‐octadecatrienoate, and methyl 13‐hydroperoxy‐9Z,11E,15Z‐octadecatrienoate on a Lichrospher DIOL column within 33 min. Compared with a diode array detector, the ELSD proved to be more sensitive, in the case of methyl 12‐oxo‐13‐hydroxy‐9Z, 15Z‐octadecadienoate by a factor of about 15. In addition, volatile metabolites were analyzed by capillary gas chromatography. The yield of the hydroperoxide lyase product 2E‐hexenal was 49%, whereas the sum of oxylipins reached about 15%.
Use of an improved internal‐standard method in the quantitative sterol analyses of phytoplankton and oysters
Authors: Ghosh Parthasarathi , Patterson Glenn W. , Wikfors Gary H.
Published: November 2006

Most work reporting the sterol composition of living organisms has not been done quantitatively, although good quantitative data are available for fatty acids and many other cellular components using an internal‐standard method that compensates for errors during gas chromatographic analysis. In this paper, we report on the use of 7‐stigmastenyl acetate as an internal standard for sterol analysis in two species of phytoplankton and oysters produced with two different diets. This internal‐standard method provides an internal standard for this entire process of analysis, not just the gas chromatographic analysis. When analyzing 50‐μg samples of cholesterol acetate after hydrolysis and acetylation, about 30% of the sample was lost, resulting in a 30% error using the older external‐standard method. Using the internal‐standard method, the analysis error was less than 2%. Losses of sterol during analysis apparently are greater with plant and animal samples than with pure sterol standards. This internal‐standard method was shown to be extremely useful, especially for samples with less than 500 μg of sterol. Finally, the standard error in sterol analysis is much lower when the internal‐standard, method is used, allowing statistical distinctions that are not possible otherwise. Use of 7‐stigmastenyl acetate as an internal standard offers several advantages over the use of cholestane.
High‐resolution nuclear magnetic resonance spectroscopy —Applications to fatty acids and triacylglycerols
Authors: Lie Ken Jie Marcel S. F. , Mustafa J.
Published: November 2006

During the past two decades, nuclear magnetic resonance spectroscopy (NMR) has played an ever‐increasing role in the structural determination of fatty acids, fatty acid derivatives and analogues, and in the analysis of the structures of triacylglycerols including the quantitative analysis of lipid mixtures. This article discusses some of the results obtained through the application of the NMR technique to lipid molecules and reviews the literature. To maintain brevity, this article does not cover the underlying theory of NMR spectroscopy as numerous books devoted to modern NMR spectroscopy have been published.
Synthesis and nuclear magnetic resonance properties of all geometrical isomers of conjugated linoleic acids
Authors: Lie Ken Jie Marcel S. F. , Pasha Mohammed Khysar , Alam Mohammad Shahin
Published: November 2006

Pure geometric isomers of conjugated linoleic acid were prepared from castor oil as the primary starting material. Methyl octadeca‐9Z, 11E‐dienoate (2) and methyl octadeca‐9Z, 11Z‐dienoate (4) were obtained by zinc reduction of methyl santalbate (1, methyl octadec‐11E‐en‐9‐ynoate) and methyl octadec‐11 Z‐en‐9‐ynoate (3), respectively, as the key intermediates. Methyl octadeca‐9E, 11E‐dienoate (8) and methyl octadeca‐9E, 11Z‐dienoate (9) were prepared by demesylation of the mesyloxy derivative of methyl ricinelaidate (6, methyl 12‐hydroxy‐octadec‐9 E‐enoate). A study of the nuclear magnetic resonance spectral properties was carried out and the shifts of the olefinic carbon atoms of 18:2(9Z, 11E) (2) and 18:2(9E, 11Z) (9) were readily identified by a combination of incredible natural abundance double quantum transfer experiment, heteronuclear multiple bond correlation, and 1H−13C correlation spectroscopy correlation techniques. Doubts remain in the absolute identification of the individual olefinic carbon atoms of the 18:2(9Z, 11Z) (4) and 18:2(9E, 11E) (8), except the fact that the shifts of the “inner” (C‐10 and C‐11) and “outer” (C‐9 and C‐12) positioned olefinic carbon atoms of the conjugated diene system are distinguishable.
Breast milk fatty acid composition: A comparative study between Hong Kong and Chongqing Chinese
Authors: Chen Z. Y. , Kwan K. Y. , Tong K. K. , Ratnayake W. M. N. , Li H. Q. , Leung S. S. F.
Published: November 2006

The fatty acids of milk samples obtained from 51 Hong Kong Chinese and 33 Chongqing Chinese (Si Chuan Province, China) were analyzed by gas‐liquid chromatography. Compared with those of published data for Canadian and other Western countries, the Chinese milk from both Hong Kong and Chongqing contained higher levels of longer‐chain polyunsaturated fatty acids, particularly docosahexaenoic acid (22:6n‐3) and arachidonic acid (20:4n‐6). In contrast, the content of trans fatty acids in the Chinese milk was lower compared with those for Canadian and other Western countries. Longitudinally, the concentrations of 22:6n‐3 and 20:4n‐6 gradually decreased when lactation progressed from colostrum (week 1) to mature (week 6). Over the same interval, linoleic acid (18:2n‐6) remained unchanged in Chongqing Chinese but significantly increased in Hong Kong Chinese. Unlike 18:2n‐6, linolenic acid (18:3n‐3) increased in Chongqing Chinese but remained unchanged in Hong Kong Chinese throughout the study. The total milk fat also increased with the duration of lactation. In addition, the milk of Chongqing Chinese had higher total milk fat than that of Hong Kong Chinese and Canadians. The content of erucic acid (22:1n‐9) increased with the progression of lactation in Chongqing Chinese, indicating that there was a switch in dietary consumption from fats of animal origin to rapeseed oil when lactation reached week 6. The present study showed that Hong Kong and Chongqing Chinese had a different fatty acid profile in many ways, which largely reflected a different dietary habit and life‐style in these two places.
Low‐dose eicosapentaenoic or docosahexaenoic acid administration modifies fatty acid composition and does not affect susceptibility to oxidative stress in rat erythrocytes and tissues
Authors: Calviello Gabriella , Palozza Paola , Franceschelli Piergiorgio , Bartoli Gianna Maria
Published: November 2006

In view of the promising future for use of n‐3 polyunsaturated fatty acids (PUFA) in the prevention of cancer and cardiovascular diseases, it is necessary to ensure that their consumption does not result in detrimental oxidative effects. The aim of the present work was to test a hypothesis that low doses of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) do not induce harmful modifications of oxidative cell metabolism, as modifications of membrane fatty acid composition occur. Wistar rats received by gavage oleic acid, EPA, or DHA (360 mg/kg body weight/day) for a period of 1 or 4 wk. Fatty acid composition and α‐tocopherol content were determined for plasma, red blood cell (RBC) membranes, and liver, kidney, lung, and heart microsomal membranes. Susceptibility to oxidative stress induced by tert‐butylhydroperoxide was measured in RBC. EPA treatment increased EPA and docosapentaenoic acid (DPA) content in plasma and in all the membranes studied. DHA treatment mainly increased DHA content. Both treatments decreased arachidonic acid content and n‐6/n‐3 PUFA ratio in the membranes, without modifying the Unsaturation Index. No changes in tissue α‐tocopherol content and in RBC susceptibility to oxidative stress were induced by either EPA or DHA treatment. The data suggest that EPA and DHA treatments can substantially modify membrane fatty acids, with‐out increasing susceptibility to oxidative stress, when administered at low doses. This opens the possibility for use of low doses of n‐3 PUFA for chemoprevention without risk of detrimental secondary effects.
Oxidation reactions of acetylenic fatty esters with selenium dioxide/tert‐butyl hydroperoxide
Authors: Lie Ken Jie Marcel S. F. , Khysar Pasha Mohammed , Shahin Alam Mohammad
Published: November 2006

Reaction of methyl undec‐10‐ynoate (1) with selenium dioxide/tert‐butyl hydroperoxide (TBHP) in aqueous dioxane gave methyl 9‐oxo‐undec‐10‐ynoate (2, 9%) and 9‐hydroxy‐undec‐10‐ynoate (3, 60%), while methyl octadec‐9‐ynoate (4) yielded mixtures of positional isomers of mono‐keto (viz. methyl 8‐oxo‐ and 11‐oxo‐octadec‐9‐ynoate, 5, 5%), hydroxy‐keto (viz. methyl 8‐hydroxy‐11‐oxo‐and 11‐hydroxy‐8‐oxo‐octadec‐9‐ynoate, 6, 10%), and dihydroxy (viz. methyl 8,11‐dihydroxy‐octadec‐9‐ynoate, 7, 24%) derivatives. Similar treatment of a conjugated diacetylenic fatty ester (methyl octadeca‐6,8‐diynoate, 8) furnished a mixture of methyl 5‐oxo‐and 10‐oxo‐octadeca‐6,8‐diynoate (9, 12%) and a complex mixture of very polar products. Reaction of methyl octadec‐11E‐en‐9‐ynoate (methyl santalbate) (10) with selenium dioxide/TBHP in aqueous dioxane gave exclusively a mixture of regiospecific products, viz. methyl 8‐oxo‐octadec‐11(E) Z‐en‐9‐ynoate (11, 6%) and methyl 8‐hydroxy‐octadec‐11 E‐en‐9‐ynoate (12, 70%). The structures of the various products were determined by a combination of spectroscopic and mass spectral analyses.
The effect of dietary docosahexaenoic acid on plasma lipoproteins and tissue fatty acid composition in humans
Authors: Nelson G. J. , Schmidt P. C. , Bartolini G. L. , Kelley D. S. , Kyle David
Published: November 2006

Normal, healthy male volunteers (n=6) were fed diets [high docosahexaenoic acid‐DHA] containing 6 g/d of DHA for 90 d. The stabilization (low‐DHA) diet contained less than 50 mg/d of DHA. A control group (n=4) remained on the low‐DHA diet for the duration of the study (120 d). Blood samples were drawn on study days 30 (end of the stabilization period), 75 (midpoint of the intervention period), and 120 (end of the intervention period). Adipose tissue (AT) samples were taken on days 30 and 120. The plasma cholesterol (C), low density lipoprotein (LDL)‐C and apolipoproteins (apo) [Al, B, and lipoprotein (a)] were unchanged after 90 d, but the triglycerides (TAG) were reduced from a mean value of 76.67±24.32 to 63.83±16.99 mg/dL (n=6, P<0.007 using a paired t‐test) and the high density lipoprotein (HDL)‐C increased from 34.83±4.38 mg/dL to 37.83±3.32 mg/dL (n=6, P<0.017 using a paired t‐test). The control group showed no significant reduction in plasma TAG levels. Apo‐E, however, showed a marked increase in the volunteers’ plasma after 90 d on the high‐DHA diet, from 7.06±4.47 mg/dL on study day 30 to 12.01±4.96 mg/dL on study day 120 (P<0.002 using a paired t‐test). The control subjects showed no significant change in the apo‐E in their plasma (8.46±2.90 on day 30 vs. 8.59±2.97 on day 120). The weight percentage of plasma DHA rose from 1.83±0.22 to 8.12±0.76 after 90 d on the high‐DHA diet. Although these volunteers were eating a diet free of eicosapentaenoic acid (EPA), plasma EPA levels rose from 0.38±0.05 to 3.39±0.52 (wt%) after consuming the high‐DHA diet. The fatty acid composition of plasma lipid fractions—cholesterol esters, TAG, and phospholipid—showed marked similarity in the enrichment of DHA, about 10%, after the subjects consumed the high‐DHA diet. The DHA content of these plasma lipid fractions varied from less than 1% (TAG) to 3.5% (phospholipids) at baseline, study day 30. EPA also increased in all plasma lipid fractions after the subjects consumed the high‐DHA diet. There were no changes in the plasma DHA or EPA levels in the control group. Consumption of DHA also caused an increase in AT levels of DHA, from 0.10±0.02 to 0.31±0.07 (wt%) (n=6, P<0.001 using a paired t‐test), but the amount of EPA in their AT did not change. Thus, dietary DHA will lower plasma TAG without EPA, and DHA is retroconverted to EPA in significant amounts. Dietary DHA appears to enhance apo‐E synthesis in the liver. It appears that DHA can be a safe and perhaps beneficial supplement to human diets.
Epicoprostanol found in adipocere from five human autopsies
Authors: Adachi Junko , Ueno Yasuhiro , Miwa Atsuko , Asano Migiwa , Nishimura Akiyoshi , Tatsuno Yoshitsugu
Published: November 2006

Adipocere formation is well known as a later postmortem change. We collected adipocere from five male victims which had been submerged under the sea or fresh water for 1 mon to 4 yr. Fresh subcutaneous fat of a male victim who died from a cerebral contusion was used as the control. The samples were homogenized, and the lipids were extracted with chloroform and methanol followed by injection into a gas chromatograph and a gas chromatograph‐mass spectrometer. We detected hydroxy fatty acids (10‐hydroxyocatadecanoic and 10‐hydroxyhexadecanoic acid) as well as 10‐ketooctadecanoic acid in adipocere, but not in the control. In addition, we found for the first time a cholesterol‐related peak with a molecular ion of 388 in adipocere and identified it as epicoprostanol, suggesting not only oxidation but also reduction had occurred during the formation of adipocere. In addition, we showed the time‐course of epicoprostanol accumulation. The relationship between the time of adipocere formation and the characteristic lipid composition is discussed.
Generation and remodeling of highly polyunsaturated molecular species of rat hepatocyte phospholipids
Authors: Schmid Patricia C. , Spimrova Ilona , Schmid Harald H. O.
Published: November 2006

Freshly isolated rat hepatocytes were incubated for 20 min with [U‐14C]glycerol in the presence or absence of unlabeled linoleic (18∶2n‐6), arachidonic (20∶4n‐6), or docosahexaenoic (22∶6n‐3) acid, added as albumin complex in 10% ethanol. Most of the radioactivity (≈95%) recovered in hepatocyte lipids was present in phosphatidylcholine (PC), phosphatidylethanolamine (PF), and triacylglycerol (TAG). The presence of exogenous fatty acids resulted in (i) higher incorporation of [U‐14C]glycerol, (ii) higher percentage of label in TAG, and (iii) enhanced formation of PC and PE molecular species bearing the exogenous fatty acid at both the sn‐1 and sn‐2 positions of glycerol. In each case, these molecular species contained 60 to 70% of the label in that lipid class. Further incubation of the cells for 40 and 80 min in the absence of labeled substrate and exogenous fatty acids resulted in a redistribution of label among PC and PE molecular species due to deacylation‐reacylation at the sn‐1 position of glycerol.
Analysis of the seed oil of Heisteria silvanii (Olacaceae)—A rich source of a novel C18 acetylenic fatty acid
Authors: Spitzer Volker , Tomberg Werner , Hartmann Rudolf , Aichholz Reiner
Published: November 2006

Besides some usual fatty acids (FA), two conjugated ene‐yne acetylenic FA [trans‐10‐heptadecen‐8‐ynoic acid (pyrulic acid) (7.4%), and trans‐11‐octadecen‐9‐ynoic acid (ximenynic acid) (3.5%)], a novel ene‐yne‐ene acetylenic FA [cis‐7, trans‐11‐octadecadiene‐9‐ynoic acid (heisteric acid) (22.6%)], and 9,10‐epoxystearic acid (0.6%) could be identified in the seed oil of Heisteria silvanii (Olacaceae). Two further conjugated acetylenic FA [9,11‐octadecadiynoic acid (0.1%) and 13‐octadecene‐9,11‐diynoic acid (0.4%)] were identified tentatively by their mass spectra. The FA mixture has been analyzed by gas chromatography/mass spectrometry (GC/MS) of their methyl ester and 4,4‐dimethyloxazoline derivatives. The structure of heisteric acid was elucidated after isolation via preparative silver ion thin‐layer chromatography and by various spectroscopic methods [ultraviolet; infrared; 1H, 13C nuclear magnetic resonance (NMR); 1H−1H and 1H−13C correlation spectroscopy]. To determine the position of the conjugated ene‐yne‐ene system, the NMR spectra were also measured after addition of the lanthanide shift reagent Resolve‐Al EuFODTM. Furthermore, the triyglyceride mixture was analyzed by high‐temperature GC and high‐temperature GC coupled with negative chemical ionization MS. A glass capillary column coated with a methoxy‐terminated 50%‐diphenyl‐50%‐dimethylpolysiloxane was used for the separation of the triacylglycerol (TAG) species. No evidence of decomposition of the TAG species containing conjugated ene‐yne‐ene FA was observed. Twenty‐six species of the separated TAG were identified by means of their abundant quasi molecular ion [M−H]− and their corresponding carboxylate anions [RCOO]− of the fatty acids, respectively. The major molecular species of the TAG were found to be 16:0/18:1/18:1, 16:0/18:1/18:3 (heisteric acid), 17:2 (pyrulic acid)/18:1/18:1, 18:1/18:1/18:3 (heisteric acid). The TAG containing acetylenic FA showed an unexpected increase of the retention time in comparison to the TAG containing usual FA, thus making the prediction of the elution order of lipid samples containing acetylenic FA difficult.
Elution factors of synthetic oxotriacylglycerols as an aid in identification of peroxidized natural triacylglycerols by reverse‐phase high‐performance liquid chromatography with electrospray mass spectrometry
Authors: Sjövall Olli , Kuksis Arnis , Marai Lajos , Myher John J.
Published: November 2006

Selected elution factors were determined for model oxotriacylglycerols as an aid in identification of the peroxidation products of natural triacylglycerols by reverse‐phase high‐performance liquid chromatography (HPLC) with electrospray mass spectrometry (LC/ES/MS). For this purpose synthetic triacylglycerols of known structure were converted to hydroperoxides, hydroxides, epoxides, and core aldehydes and their dinitrophenylhydrazones by published procedures. The oxotriacylglycerols were resolved by normal‐phase thin‐layer chromatography and reverse‐phase HPLC, and the identities of the oxotriacylglycerols confirmed by LC/ES/MS. Elution factors of oxotriacylglycerols were determined in relation to a homologous series of saturated triacylglycerols, ranging from 24 to 54 acylcarbons, and analyzed by reverse‐phase HPLC, using a gradient of 20–80% isopropanol in methanol as eluting solvent and an evaporative light‐scattering detector. It was shown that the elution times varied with the nature of the functional group and its regiolocation in the triacylglycerol molecule. A total of 31 incremental elution factors were calculated from chromatography of 33 oxygenated and nonoxygenated triacylglycerol species, ranging in carbon number from 36 to 54 and in double‐bond number from 0 to 6.
Effect of modified dairy fat on postprandial and fasting plasma lipids and lipoproteins in healthy young men
Authors: Tholstrup Tine , Sandström Brittmarie , Hermansen John E. , Hølmer Gunhild
Published: November 2006

Fatty acid profile of milk fat can be modified by cow feeding strategies. Our aim was postprandially and after 4 wk to compare the effect of a modified milk fat (M diet) [with 16% of the cholesterolemic saturated fatty acid (C12–16) replaced by mainly oleic and stearic acids] with the effect of D diet, including a conventional Danish milk fat on plasma lipids and lipoproteins. A side effect of the cow feeding regime was a 5% (w/w) increase in trans fatty acid in M diet. Eighteen subjects were fed for two periods of 4 wk strictly controlled isoenergetic test diets with 40% of energy from total fat and the same content of dietary cholesterol in a randomized study with cross‐over design. Contrary to expectations, fasting low density lipoprotein (LDL) cholesterol concentration did not differ after the experimental periods. However, M diet resulted in a higher fasting total triacylglycerol concentration compared to D diet (P=0.009). Postprandial samples were taken at two different occasions (i) at day 21, after breakfast and lunch and (ii) on the last day of the study 2, 4, 6, and 8 h after a fat load. Postprandial plasma triacylglycerol and chylomicron triacylglycerol showed higher peak values after D diet than M diet (interaction effect, diet × times P<0.05). In conclusion, M diet did not lower LDL cholesterol compared to D diet. Thus any cholesterol‐lowering effect of oleic and stearic acids may have been obscured by the high content of cholesterol‐raising saturated fatty acids in milk fat. A higher content of the trans fatty acids in M diet might have counteracted the cholesterol neutral/decreasing effect and increased plasma triacylglycerol.
Regulation of very low density lipoprotein apo B metabolism by dietary fat saturation and chain length in the guinea pig
Authors: Abdel‐Fattah Ghada , Fernandez Maria Luz , McNamara Donald J.
Published: November 2006

Studies investigated the effects of dietary fatty acid composition and saturation on the regulation of very low density lipoprotein (VLDL) apo B flux, clearance, and conversion to low density lipoprotein (LDL) in guinea pigs fed semipurified diets containing 15% (w/w) corn oil (CO), lard (LA), or palm kernel oil (PK). Plasma cholesterol levels were highest with dietary PK (3.1±1.0 mmol/L) followed by LA (2.4±0.4 mmol/L) and CO (1.6±0.4 mmol/L) intake. VLDL particles were larger (P<0.05) in the LA (78±7 nm) and PK (69±10 nm) groups compared to animals fed CO (49±5 nm). VLDL‐apo B fractional catabolic rates (FCR) were highest in guinea pigs fed the LA diet (P<0.05) and VLDL apo B flux, estimated from VLDL 125I‐apo B turnover kinetics, were higher in LA compared to PK or CO fed guinea pigs. In the case of PK consumption, the kinetic estimates of VLDL apo B flux significantly underestimated rates compared to direct VLDL apo B secretion measurements and LDL turnover analyses. These data demonstrate that differences in the composition and amount of saturated fatty acids have differential effects on VLDL apo B flux, catabolism, and conversion to LDL which, together with changes in LDL receptor‐mediated catabolism, determine plasma LDL cholesterol levels in guinea pigs. The data also indicate that kinetic analysis of VLDL metabolism in PK fed animals is inaccurate possibly due to the presence of a small, nonequilibrating pool of newly synthesized VLDL which is rapidly converted to LDL.
Enhancement of low density lipoprotein binding to both low density lipoprotein receptor‐positive and‐ negative cells by tetracycline antibiotics
Authors: Miura Shinji , Hasumi Keiji , Takayasu Ritsuko , Sugimoto Maki , Endo Akira
Published: November 2006

Some tetracycline (TC) antibiotics, including TC and anhydrotetracycline, have been found to enhance specific binding of low density lipoprotein (LDL) to both LDL receptor‐positive and‐negative cells at relatively higher concentrations. When incubated at 37°C, the ability of LDL receptor‐negative human fibroblasts to bind 125I‐LDL was increased from<2 to 45 ng/mg by 170 μM TC. In normal human fibroblasts and Hep G2 cells, 125I‐LDL binding was elevated 1.4‐ to 2‐fold by 113 μM TC. The 125I‐LDL binding in the presence of TC was diminished by both heparin and EDTA. The enhancement by TC was not observed when 125I‐LDL binding was assayed at 4°C. TC enhanced LDL binding to paraformaldehyde‐fixed Hep G2 cells, excluding LDL receptor induction in the mechanism. These results demonstrated that TC enhanced cellular LDL binding through a process not involving functional LDL receptors.
Stereospecific metabolism of isomeric epoxyoctadecanoic acids in the lactone‐producing yeast Sporidiobolus salmonicolor
Authors: Haffner Thomas , Tressl Roland
Published: November 2006

The metabolic course of four isomeric epoxyfatty acids derived from oleic‐, elaidic‐, (Z)‐, and (E)‐vaccenic acids in the lactone‐producing yeast, Sporidiobolus salmonicolor, was studied by using the deuterium‐labeled precursors. Dihydroxy‐, hydroxyoxo‐, and hydroxy fatty acids as well as γ‐lactones were identified as metabolic intermediates. Quantitative analysis of the label content and estimation of the enantiomeric composition of the lactones established that, in the first step, the racemic epoxyfatty acids were enantiospecifically hydrolyzed by an epoxide hydrolase. During the subsequent metabolism, the stereochemical orientation of the hydroxy groups of the dihydroxyfatty acids were modified by an oxidation/reduction step.