bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholesterol oxidation in meat from chickens fed α‐tocopherol‐and β‐carotene‐supplemented diets with different unsaturation grades
Authors: Maraschiello C. , Esteve E. , García Regueiro J. A. 
Published: November 2006

AbstractThe production of B‐ring and side‐chain oxysterols was evaluated in meat from chickens fed diets differing by the kind of oil or fat added. The effect of supplementary levels of natural antioxidants, as α‐tocopherol and β‐carotene, on the meat cholesterol oxidative stability was also studied. Lard, sunflower and olive oil were used as dietary fat. Raw and cooked meats were analyzed for oxysterols, and cholesterol was also quantified. Oxysterol analyses were carried out by combining the use of solid‐phase extraction, thin‐layer chromatography, capillary gas chromatography, and capillary gas chromatography‐mass spectrometry. Oxysterols were detected within the 0.1–0.5 μg/g range in raw meat. Cooking increased the oxysterol content of the meat, and levels as high as 5 μg/g muscle tissue were observed. B‐Ring oxysterols were mainly produced: the α‐and the β‐epoxycholesterols, the 7α‐and 7β‐hydroxycholesterols, and the 7‐ketocholesterol. The results showed that the meat from the chickens fed the olive oil‐based diet containing α‐tocopherol at 200 mg/kg of diet presented the best cholesterol oxidative stability. A positive effect could not be found for dietary β‐carotene administered at levels of 15 and 50 mg/kg of diet. Furthermore, a significant decrease in the tissue cholesterol content was observed with the olive and the sunflower oil‐based diets.
Tanacetum (Chrysanthemum) corymbosum seed oil—A rich source of a novel conjugated acetylenic acid
Authors: Tsevegsuren Nanzad , Christie William W. , Lösel Dorothy 
Published: November 2006

AbstractA new conjugated trans,trans‐diunsaturated acetylenic acid (17%), found for the first time in nature as a main component of the seed oil of Tanacetum (Chrysanthemum) corymbosum, was shown to be octadeca‐8t,10t‐dien‐12‐ynoic acid. Another already known naturally occurring acetylenic acid, crepenynic acid (10%), was found also in the seed oil. The structure of this new unusual fatty acid was confirmed by chromatographic (thin‐layer chromatography, gas chromatography, high‐performance liquid chromatography) and spectroscopic (infrared, ultraviolet, mass spectrometry) methods by using different chemical derivatizations (deuteration, preparation of picolinyl ester, dimethyloxazoline, and maleic anhydride adduct).
Fullerene lipids: Synthesis of dialkyl 1,2‐[6,6]‐methano‐[60]‐fullerene dicarboxylate derivatives
Authors: Lie Ken Jie Marcel S. F. , Cheung Sunny Wai‐Hung 
Published: November 2006

AbstractReaction of C60 fullerene with dialkyl bromomalonate (where the alkyl groups consist of short‐, medium‐, and long‐saturated chains or unsaturated long chains) in the presence of sodium hydride gives [6,6]‐bridged mono‐adducts of methanofullerene. The spectroscopic properties of such fullerenoid lipids are reported.
9‐Hydroxy‐traumatin, a new metabolite of the lipoxygenase pathway
Authors: Gardner Harold W. 
Published: November 2006

Abstract9‐Hydroxy‐traumatin, 9‐hydroxy‐12‐oxo‐10E‐dodecenoic acid, was isolated as a product of 13S‐hydroperoxy‐9Z, 11E‐octadecadienoic acid as catalyzed by enzyme preparations of both soybean and alfalfa seedlings. This suggested that 9Z‐traumatin, 12‐oxo‐9Z‐dodecenoic acid, was being converted into 9‐hydroxy‐traumatin in an analogous manner to the previously identified enzymic conversion of 3Z‐nonenal and 3Z‐hexenal into 4‐hydroxy‐2E‐nonenal and 4‐hydroxy‐2E‐hexenal, respectively. Other metabolites of 13S‐hydroperoxy‐9Z,11E‐octadecadienoic acid were similar for both soybean and alfalfa seedling preparations, and they are briefly described.
Rate constants for quenching singlet oxygen and activities for inhibiting lipid peroxidation of carotenoids and α‐tocopherol in liposomes
Authors: Fukuzawa Kenji , Inokami Yasuki , Tokumura Akira , Terao Junji , Suzuki Asahi 
Published: November 2006

AbstractThe 1O2 quenching rate constants (kQ) of α‐tocopherol (α‐Toc) and carotenoids such as β‐carotene, astaxanthin, canthaxanthin, and lycopene in liposomes were determined in light of the localization of their active sites in membranes and the micropolarity of the membrane regions, and compared with those in ethanol solution. The activities of α‐Toc and carotenoids in inhibiting 1O2‐dependent lipid peroxidation (reciprocal of the concentration required for 50% inhibition of lipid peroxidation: [IC50]−1) were also measured in liposomes and ethanol solution and compared with their kQ values. The kQ and [IC50]−1 values were also compared in two photosensitizing systems containing Rose bengal (RB) and pyrenedodecanoic acid (PDA), respectively, which generate 1O2 at different sites in membranes. The kQ values of α‐Toc were 2.9×108M−1s−1 in ethanol solution and 1.4×107 M−1s−1 (RB system) or 2.5×106 M−1s−1 (PDA system) in liposomes. The relative [IC50]−1 value of α‐Toc in liposomes was also five times higher in the RB system than in the PDA‐system. In consideration of the local concentration of the OH‐group of α‐Toc in membranes, the kQ value of α‐Toc in liposomes was recalculated as 3.3×106 M−1s−1 in both the RB and PDA systems. The kQ values of all the carotenoids tested in two photosensitizing systems were almost the same. The kQ value of α‐Toc in liposomes was 88 times less than in ethanol solution, but those of carotenoids in liposomes were 600–1200 times less than those in ethanol solution. The [IC50]−1 value of α‐Toc in liposomes was 19 times less than that in ethanol solution, whereas those of carotenoids in liposomes were 60–170 times less those in ethanol solution. There were no great differences (less than twice) in the kq and [IC50]−1 values of any carotenoids. The kQ values of all carotenoids were 40–80 times higher than that of α‐Toc in ethanol solution but only six times higher that of α‐Toc in liposomes. The [IC50]−1 values of carotenoid were also higher than that of α‐Toc in ethanol solution than in liposomes, and these correlated well with the kQ values.
Dietary oxidized cholesterol modulates cholesterol metabolism and linoleic acid desaturation in rats fed high‐cholesterol diets
Authors: Osada Kyoichi , Kodama Takehiro , Yamada Koji , Nakamura Shingo , Sugano Michihiro 
Published: November 2006

AbstractThe interactive effect of high dietary levels of oxidized cholesterol on exogenous cholerterol and linoleic acid metabolism was examined in male 4‐wk‐old Sprague‐Dawley rats given high‐cholesterol diets. The rats were pair‐fed purified diets free of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing 93% oxidized cholesterol) for 3 wk. Hepatic 3‐hydroxy‐3‐methylglutaryl CoA reductase activity was reduced in rats given cholesterol alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7α‐hydroxylase activity was lowered only when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the other hand, the activity of hepatic Δ6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity. As a result, the Δ6 desaturation index, 20∶3n‐6+20∶4n‐6/18∶2n‐6, in liver and serum phosphlipids tended to be higher in the group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at high levels together with a high cholesterol diet.
The cholesterol‐lowering effect of guar gum in rats is not accompanied by an interruption of bile acid cycling
Authors: Favier Marie‐Laure , Bost Pierre‐Etienne , Demigné Christian , Rémésy Christian 
Published: November 2006

AbstractA viscous hydrocolloid (guar gum, GG; 2.5% of the diet) or a steroid sequestrant (cholestyramine; 0.5% of the diet) was included in semipurified diets containing 0.2% cholesterol to compare the cholesterol‐lowering effects of each agent in rats. In the present model, GG significantly lowered plasma cholesterol (−25%), especially in the density <1.040 kg/L fraction, whereas cholestyramine was less potent. Bile acid fecal excretion significantly increased only in rats fed cholestyramine, similar to the cecal bile acid pool; the biliary bile acid secretion was accelerated by GG, but not their fecal excretion, whereas GG effectively enhanced neutral sterol excretion. As a result, the total steroid balance (+13 μmol/d in the control) was shifted toward negative values in rats fed the GG or cholestyramine diets (−27 or −50 μmol/d, respectively). Both agents induced liver 3‐hydroxy‐3‐methylglutaryl‐CoA reductase, but cholestyramine was more potent than GG in this respect. The present data suggest that, at a relative low dose in the diet, GG may be more effective than cholestyramine in lowering plasma cholesterol by impairing cholesterol absorption and by accelerating the small intestine/liver cycling of bile acids, which is interestingly, accompanied by reduction of bile acid concentration in the large intestine.
Surface composition regulates clearance from plasma and triolein lipolysis of lipid emulsions
Authors: Arimoto Itaru , Matsumoto Chizuko , Tanaka Masafumi , Okuhira Keiichirou , Saito Hiroyuki , Handa Tetsurou 
Published: November 2006

AbstractSphingomyelin (SM) and cholesterol (Chol) are major surface lipid constituents of plasma lipoproteins. We investigated the effects of SM and Chol on the plasma clearance of lipid emulsions as a model for lipoprotein particles in rats. The presence of Chol facilitated the removal of emulsion particles from plasma, whereas SM delayed particle removal. Preinjection of lactoferrin, an inhibitor of the apolipoprotein E (apoE) receptor, revaled that the differences in clearance of emulsions were due to the differences in affinity for the apoE receptor. Measurement of apolipoprotein binding suggested that the balance of apoE and apoC (apoC‐II and apoC‐III) bound to emulsions caused the difference in plasma clearance of emulsion particles. That is to say, SM in the emulsion surface decreased binding of apoE, which led to a longer circulation of emulsion particles in plasma. Chol, on the other hand, decreased the ratio of apoC to apoE, which may have promoted emulsion uptake through the apoE receptor. We also examined in vitro lipolysis using immobilized lipoprotein lipase (LPL) in a heparin affinity column. Lipolysis rates were significantly reduced by the incorporation of SM into the emulsion surface, but not by the incorporation of Chol, indicating that SM in the lipoprotein surface is an important lipid component regulating LPL‐mediated lipolysis. Our results suggest that the presence of SM and Chol in the lipoprotein surface plays an important role in the circulation behavior and LPL‐mediated lipolysis of lipid emulsions through their effect on the selectivity of plasma protein binding.
Remodeling of phospholipid fatty acids in mitochondrial membranes of estivating snails
Authors: Stuart J. A. , Gillis T. E. , Ballantyne J. S. 
Published: November 2006

AbstractThe effects of estivation on the phospholipid‐specific fatty acid composition of mitochondrial membranes in the hepatopancreas of the terrestrial snail Cepaea nemoralis were investigated. The fatty acid composition of all phospholipids was significantly altered in snails estivating for 6 wk, indicating that substantial remodeling occurs. The most profound changes occurred in cardiolipin (CL). CL of estivating snails was 13‐fold more saturated, contained 9‐fold more monoenes, and had 45% fewer polyenes than in active snails. These differences were due, in part, to a reduction in linoleic acid (18:2n‐6) content of CL from estivators. As in mammals, CL of active snails appears to preferentially incorporate 18:2n‐6, which accounts for 60% of the acyl chains in this phospholipid. This proportion was reduced by 50% in estivators. Changes in the fatty acyl content of other phospholipids of estivating snails included increased monoenes in phosphatidylethanolamine (PE) and phosphatidylinositol, reduced ratios of n‐3/n‐6 polyenes in PE and phosphatidylcholine (PC), and an increased n‐3/n‐6 ratio in phosphatidylserine (PS). Arachidonic acid (20:4n‐6) levels were reduced in PS but increased in CL and PC. Taken together, these alterations to fatty acid composition are consistent with decreased biological activity of membrane‐related processes which occur in conjunction with the reduction of mitochondrial aerobic metabolism observed during estivation.
Changes in tissue polyunsaturated fatty acids with age, in spontaneously hypertensive rats
Authors: Delachambre Marie‐Claire , Narce Michel , Asdrubal Philippe , Poisson Jean‐Pierre 
Published: November 2006

AbstractThe relationship between the biosynthesis of long‐chain fatty acids and their distribution in the key organs of hypertension is of considerable interest because of their role in the production of vasoactive eicosanoids and their effects on membrane properties. The present study analyzed the fatty acid compositions of the total lipids in the kidney, aorta, heart, and hepatocytes of 1‐, 3‐, and 6‐mon‐old spontaneously hypertensive rats (SHR) and their normotensive controls, Wistar Kyoto rats (WKY) by capillary gas chromatography. The major changes concerned the polyunsaturated fatty acids (PUFA). The percentage of arachidonic acid (AA) was significantly greater in the 1‐mon‐old SHR kidney than in the WKY kidney, but it was lower at 3 and 6 mon. The percentage of eicosapentaenoic acid was very low in the SHR kidney. The results for the aorta were similar, with marked decreases in 18:2n−6 and 18:3n−3 in SHR aged 1 and 6 mon. Despite a higher proportion of 18:2n−6 and AA at 6 mon, there was no major change in the SHR heart lipids. The fatty acid spectrum in the liver provides additional evidence for the previously reported inhibition of desaturase activities in SHR. Thus, this study shows that the PUFA composition is modified differently in different tissues in SHR, and this may be related to the pathogenesis of hypertension in these animals.
A new conjugated linoleic acid isomer, 7 trans, 9 cis‐octadecadienoic acid, in cow milk, cheese, beef and human milk and adipose tissue
Authors: Yurawecz Martin P. , Roach John A. G. , Sehat Najibullah , Mossoba Magdi M. , Kramer John K. G. , Fritsche Jan , Steinhart Hans , Ku Youh 
Published: November 2006

AbstractThe identity of a previously unrecognized conjugated linoleic acid (CLA) isomer, 7 trans, 9 cis‐octadecadienoic acid (18∶2) was confirmed in milk, cheese, beef, human milk, and human adipose tissue. The 7 trans, 9 cis‐18∶2 isomer was resolved chromatographically as the methyl ester by silver ion‐high‐performance liquid chromatography (Ag+‐HPLC); it eluted after the major 9 cis, 11 trans‐18∶2 isomer (rumenic acid) in the natural products analyzed. In the biological matrices in‐vestigated by Ag+‐HPLC, the 7 trans, 9 cis‐18∶2 peak was generally due to the most abundant minor CLA isomer, ranging in concentration from 3 to 16% of total CLA. By gas chromatography (GC) with long polar capillary columns, the methyl ester of 7 trans, 9 cis‐18∶2 was shown to elute near the leading edge of the major 9 cis, 11 trans‐18∶2 peak, while the 4,4‐dimethyloxazoline (DMOX) derivative permitted partial resolution of these two CLA isomers. The DMOX derivative of this new CLA isomer was analyzed by gas chromatography‐electron ionization mass spectrometry (GC‐EIMS). The double bond positions were at Δ7 and Δ9 as indicated by the characteristic mass spectral fragment ions at m/z 168, 180, 194, and 206, and their allylic cleavages at m/z 154 and 234. The cis/trans double‐bond configuration was established by GC‐direct deposition‐Fourier transform infrared as evidenced from the doublet at 988 and 949 cm−1 and absorptions at 3020 and 3002 cm−1. The 7 trans, 9 cis‐18∶2 configuration was established by GC‐EIMS for the DMOX derivative of the natural products examined, and by comparison to a similar product obtained from treatment of a mixture of methyl 8‐hydroxy‐and 11‐hydroxyoctadec‐9 cis enoates with BF3, in methanol.
Analysis of ubiquinone and tocopherol levels in normal and hyperlipidemic human plasma
Authors: Zhang Yiyi , Eriksson Mats , Dallner Gustav , Appelkvist Eeva‐Liisa 
Published: November 2006

AbstractThe type and amount of lipophilic antioxidants in plasma of hyperlipidemic patients are of great importance since they play a central role in preventing deleterious oxidation of blood lipids and proteins. Isolation and quantitation of lipophilic antioxidants from hyperlipidemic plasma samples meet great obstacles because of increased levels of various intermediary lipid products. This study was designed to develop a rapid and efficient extraction and separation procedure for simultaneous analysis of ubiquinone‐9 and‐10 as well as α‐, δ‐, and γ‐tocopherol isomers. The levels of ubiquinone‐10, α‐ and γ‐tocopherol were analyzed in human plasma samples using high‐performance liquid chromatography. Lipid extraction was performed by petroleum ether/methanol/water. After phase separation, ubiquinone was reduced to ubiquinol by sodium borohydride and the lipids were separated on a C18 column. A binary gradient with solvents containing lithium perchlorate was used, and an electrochemical detector was employed for quantitation. This procedure was also efficient for the analysis of antioxidant lipids in samples containing a large number of accumulated and interfering lipid intermediates. Thus, the procedure described here is useful for efficient and rapid quantitation of ubiquinones and tocopherols in human plasma samples, especially those originating from hyperlipidemic patients.
Evidence that commercial calf and horse sera can contain substantial amounts of trans‐10,cis‐12 conjugated linoleic acid
Authors: Park Yeonhwa , Pariza Michael W. 
Published: November 2006

AbstractWe analyzed fetal calf, newborn calf, horse, and adult cow sera for conjugated linoleic acid (CLA). All sera samples contained CLA, but the amounts varied. The predominant isomer was cis‐9,trans‐11 CLA but some samples appeared to contain substantial amounts of an isomer with the retention time of trans‐10,cis‐12 CLA.
Lectin may contribute to the atherogenicity of peanut oil
Authors: Kritchevsky David , Tepper A. , Klurfeld David M. 
Published: November 2006

AbstractPeanut oil is unexpectedly atherogenic for rats, rabbits, and primates. The lesions it produces are more fibrous than fatty. The mechanism underlying the atherogenicity of peanut oil has been elusive. Randomization of peanut oil reduces significantly its atherogenic properties, but native and randomized peanut oils have similar rates of lipolysis, and rats fed the two oils absorb and transport lipids in a similar fashion. Peanut oil differs from other oils in having a relatively high lectin content, and the randomization process markedly reduces the lectin content as well. The biologically active lectin of peanut oil has an affinity for glycoproteins found specifically on arterial smooth muscle cells. Peanut lectin has been shown to stimulate growth of smooth muscle and pulmonary arterial cells. Vigorous washing of peanut oil reduces its lectin content by 46%. Compared to rabbits fed cholesterol and peanut oil, rabbits fed cholesterol and washed peanut oil exhibited less severe atherosclerosis in the aortic arch (by 9%) and in the thoracic aorta (by 31%). The data suggest that peanut oils' endogenous lectin may contribute significantly to its atherogenic properties.
The signature 10‐hydroxy stearic acid thought to correlate with infectivity in oocysts of Cryptosporidium species is an artifact
Authors: Burkhalter Robert S. , Smith Carol A. , White David C. , Fayer Ronald , White Andrew B. 
Published: November 2006

AbstractHeating or freezing leads to loss in infectivity of oocysts of Cryptosporidium parvum toward neonatal BALB/c mice and is reflected in the profile of the polar lipid fatty acids. Upon loss of infectivity, the ratio of polar lipid to neutral lipid fatty acid decreased and the relative proportions of 18∶1n‐9 also decreased; proportions of 18∶2n‐6 and 20∶5n‐6 increased, whereas the proportions of 16∶0 remained constant with freezing. During these investigations, a novel fatty acid, 10‐OH 18∶0, was discovered in the glycolipid fraction. The identification of a fatty acid unique to species of Cryptosporidium was thought to provide a specific biomarker for this organism. Cryptosporidium also demonstrated fluctuations in absolute quantities of 10‐OH 18∶0 with events that lead to loss of infectivity. This led to the presumed correlation of this biomarker with infectious Cryptosporidium. The 10‐OH 18∶0 was putatively localized at the sn‐2 position of phosphatidylethanolamine. High‐performance liquid chromatography/electrospray ionization mass spectrometry revealed that the 10‐OH 18∶0 existed principally in the free fatty acid form. Herein, we establish that the free fatty acid 10‐OH 18∶0 was, in actuality, an artifact of the procedures for sample preparation.
Analysis of novel hydroperoxides and other metabolites of oleic, linoleic, and linolenic acids by liquid chromatography‐mass spectrometry with ion trap MSn
Authors: Oliw Ernst H. , Su Chao , Skogström Torun , Benthin Günther 
Published: November 2006

AbstractLinoleate is oxygenated by manganese‐lipoxygenase (Mn‐LO) to 11S‐hydroperoxylinoleic acid and 13R‐hydroperoxyoctadeca‐9Z,11E‐dienoic acid, whereas linoleate diol synthase (LDS) converts linoleate sequentially to 8R‐hydroperoxylinoleate, through an 8‐dioxygenase by insertion of molecular oxygen, and to 7S,8S‐dihydroxylinoleate, through a hydroperoxide isomerase by intramolecular oxygen transfer. We have used liquid chromatography‐mass spectrometry (LC‐MS) with an ion trap mass spectrometer to study the MSnmass spectra of the main metabolites of oleic, linoleic, α‐linolenic and γ‐linolenic acids, which are formed by Mn‐LO and by LDS. The enzymes were purified from the culture broth (Mn‐LO) and mycelium (LDS) of the fungusGaeumannomyces graminis. MS3analysis of hydroperoxides and MS2analysis of dihydroxy‐ and monohydroxy metabolites yielded many fragments with information on the position of oxygenated carbons. Mn‐LO oxygenated C‐11 and C‐13 of 18∶2n−6, 18∶3n−3, and 18∶3n−6 in a ratio of ∼1∶1–3 at high substrate concentrations. 8‐Hydroxy‐9(10)expoxystearate was identified as a novel metabolite of LDS and oleic acid by LC‐MS and by gas chromatography‐MS. We conclude that LC‐MS with MSnis a convenient tool for detection and identification of hydroperoxy fatty acids and other metabolites of these enzymes.