共查询到20条相似文献,搜索用时 609 毫秒
1.
G. Knothe M. O. Bagby D. Weisleder R. E. Peterson 《Journal of the American Oil Chemists' Society》1995,72(6):703-706
Several novel allylic mono- and dihydroxy fatty compounds were synthesized from Δ5, Δ7-, Δ8-, and Δ10-monounsaturated fatty
acids with the selenium dioxide/tert-butyl-hydroperoxide. Chainlengths were C19 for Δ7 and Δ10, and C20 for Δ5 and Δ8 compounds. With a full range of Δ5- to Δ11-unsaturated allylic monohydroxy fatty compounds available, position-dependent
effects in the13C-nuclear magnetic resonance spectra of these compounds are discussed. The olefinic carbon shift differences in monohydroxy
compounds, where the OH group is located between the double bond and the terminal methyl group, were plotted as a function
of double-bond distance from C1. This plot is presumably a rational function. During SeO2-based hydroxylation, lactonization of the hydroxy groups, located between the double-bond and the carboxyl group, also occurs
for Δ5 unsaturation. 相似文献
2.
G. Knothe D. Weisleder M. O. Bagby R. E. Peterson 《Journal of the American Oil Chemists' Society》1993,70(4):401-404
Oleic acid was hydroxylated in the allylic positions with the selenium dioxide/tert.-butylhydroperoxide system to give 8-hydroxy-9(E)-octadecenoic acid, 11-hydroxy-9(E)-octadecenoic acid and the novel 8,11-dihydroxy-9(E)-octadecenoic acid. This is a viable method for obtaining hydroxy fatty acids. The unsaturated hydroxy acids were hydrogenated
with the hydrazine/air system to give the cor-responding saturated products. 8,11-Dihydroxyoctadecanoic acid thus obtained
is also a novel compound. The saturated and unsaturated dihydroxy products were obtained aserythro/threo isomers as determined by nuclear magnetic resonance.
Presented in part at the 83rd AOCS Annual Meeting, Toronto, Ontario, Canada, 1992. 相似文献
3.
Column chromatography on silver ion-saturated Amberlyst XN 1010 cation exchange resin gave very good separation of a mixture
of methyl 12-hydroxy-cis-andtrans-9-octadecenoates and of methylthreo-12, 13-dihydroxy-cis- andtrans-9-octadecenoates. Comparison of the retention volumes of nonhydroxy, monohydroxy, and dihydroxy saturated and monoenoic methyl
esters and of dienoic methyl esters shows that the hydroxy group interacts with the column packing to slow passage of the
compound through the column, although the effect of a hydroxy group is less than that of atrans double bond. The effects of the hydroxy groups are additive; the ratio of retention volumes of dihydroxy ester to monohydroxy
ester is slightly larger that that of monohydroxy ester to nonhydroxy ester. The retention volume of a cis monoenoic ester
is equal to that of a hydroxytrans monoenoic ester and that of a hydroxycis monoenoic ester is equal to that of a dihydroxytrans monoenoic ester. 相似文献
4.
Nikolaus Weber Klaus Vosmann Eberhard Fehling Kumar D. Mukherjee Dieter Bergenthal 《Journal of the American Oil Chemists' Society》1995,72(3):361-368
A novel process has been described recently for the preparation of hydroxylated fatty acids (HOFA) and HOFA methyl esters
from plant oils. HOFA methyl esters prepared from conventional and alternative plant oils were characterized by various chromatographic
methods (thin-layer chromatography, high-performance liquid chromatography, and gas chromatography) and gas chromatography-mass
spectrometry as well as1H and13C nuclear magnetic resonance spectroscopy. HOFA methyl esters obtained fromEuphorbia lathyris seed oil, low-erucic acid rapeseed oil, and sunflower oil contain as major constituents methylthreo-9,10-dihydroxy octadecanoate (derived from oleic acid) and methyl dihydroxy tetrahydrofuran octadecanoates, e.g., methyl
9,12-dihydroxy-10,13-epoxy octadecanoates and methyl 10,13-dihydroxy-9,12-epoxy octadecanoates (derived from linoleic acid).
Other constituents detected in the products include methyl esters of saturated fatty acids (not epoxidized/derivatized) and
traces of methyl esters of epoxy fatty acids (not hydrolyzed). The products that contain high levels of monomeric HOFA may
find wide application in a variety of technical products. 相似文献
5.
The reactions of ruthenium VIII tetroxide (RuO4) and the ruthenium VII and VI oxyanions, perruthenate (RuO4
−) and ruthenate (RuO4
=) with hydroxy substituted and unsaturated fatty acids have been studied. At a 1:1 molar ratio, ruthenium tetroxide (RuO4) and both oxyanions (RuO4
− and RuO4
=) oxidized 12-hydroxystearic acid to 12-ketostearic acid. With 9, 10-dihydroxystearic acid, the type of oxidation products
obtained depended on the amount of ruthenium oxidant used. At high ratios of oxidant to substrate, cleavage to pelargonic
and azelaic acids occurred whereas at lower ratios, partial oxidation to diketo and acyloin derivatives predominated. The
oxidation of oleic acid with excess ruthenium tetroxide (RuO4) or perruthenate anion (RuO4
−) gave the cleavage products pelargonic and azelaic acid through the intermediate formation of dihydroxy and diketo intermediates.
Ruthenate anion (RuO4
=) did not react with the double bond of oleic acid.
Agricultural Research Service, U.S. Department of Agriculture. 相似文献
6.
G. Knothe M. O. Bagby D. Weisleder 《Journal of the American Oil Chemists' Society》1995,72(9):1021-1026
Several symmetrical alkenes were reacted with the selenium dioxide/tert.-butylhydroperoxide system to give three hydroxylated products each. These products were those of allylic mono- and dihydroxylation
(meso andthreo dihydroxy compounds) of the double bond. Some dihydroxy products were hydrogenated to give saturated 1,4-diols. The compounds
were characterized by nuclear magnetic resonance. The products have potential for application in commercial products, such
as biodiesel, lubricants, greases, and cosmetics. 相似文献
7.
Mats Hamberg 《Lipids》1992,27(12):1042-1046
A method for the determination of the absolute configuration of the alcohol group of fatty acid α,β-epoxy alcohols was developed.
The method consists of:(i) deoxygenation of the saturated epoxy alcohol to an allylic alcohol by treatment with triphenylphosphine
selenide and trifluoroacetic acid; (ii) oxidative ozonolysis of the (−)-menthoxycarbonyl derivative of the allylic alcohol;
and (iii) steric analysis of the resulting 2-hydroxy acid (methyl ester, (−)-menthoxycarbonyl derivative) by gas-liquid chromatography
using appropriate reference compounds. The result obtained, coupled with knowledge of the relative configuration of the epoxy
alcohol (erythro/threo) and of the geometrical configuration of the epoxide group (cis/trans), permitted assignment of the absolute configuration of all three asymmetric carbons of the α,β-epoxy alcohol. The method
was applied to the determination of the absolute stereochemistry of two hepoxilins recently isolated from the red algaMurrayella perilados. 相似文献
8.
Reversed‐Phase Liquid Chromatography–Quadrupole‐Time‐of‐Flight Mass Spectrometry for High‐Throughput Molecular Profiling of Sea Cucumber Cerebrosides
下载免费PDF全文
![点击此处可从《Lipids》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Usually, the chemical structures of cerebrosides in sea creatures are more complicated than those from terrestrial plants and animals. Very little is known about the method for high‐throughput molecular profiling of cerebrosides in sea cucumbers. In this study, cerebrosides from four species of edible sea cucumbers, specifically, Apostichopus japonicas, Thelenota ananas, Acaudina molpadioides and Bohadschia marmorata, were rapidly identified using reversed‐phase liquid chromatography–quadrupole‐time‐of‐flight mass spectrometry (RPLC‐QToF‐MS). [M + H]+ in positive electrospray ionization (ESI) mode were used to obtain the product ion spectra. The cerebroside molecules were selected according to the neutral loss fragments of 180 Da and then identified according to pairs of specific products of long‐chain bases (LCB) and their precursor ions. A typical predominant LCB was 2‐amino‐1,3‐dihydroxy‐4‐heptadecene (d17:1), which was acylated to form saturated and monounsaturated non‐hydroxy and monohydroxy fatty acids with 17–25 carbon atoms. Simultaneously, the occurrence of 2‐hydroxy‐tricosenoic acid (C23:1h) was characteristic of sea cucumber cerebrosides, whereas this molecule was rarely discovered in plants, mammals, or fungi. The profiles of LCB and fatty acids (FA) distribution might be related to the genera of sea cucumber. These data will be useful for identification of cerebrosides using RPLC‐QToF‐MS. 相似文献
9.
Linoleate 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 MSn mass 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 fungus Gaeumannomyces graminis. MS3 analysis of hydroperoxides and MS2 analysis 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 MSn is a convenient tool for detection and identification of hydroperoxy fatty acids and other metabolites of these enzymes. 相似文献
10.
Clavibacter sp. ALA2 oxidized n−3 and n−6 PUFA into a variety of oxylipins. Structures of products converted from EPA and DHA were determined
as 15,18-dihydroxy-14,17-epoxy-5(Z),8(Z),11(Z)-eicosatrienoic acid and 17,20-dihydroxy-16,19-epoxy-4(Z),7(Z),10(Z),13(Z)-docosatetraenoic acid by GC-MS and NMR analyses. In contrast, γ-linolenic acid and arachidonic acid were converted to diepoxy
bicyclic FA, tetrahydrofuranyl monohydroxy FA, and trihydroxy FA. Thus, the structures of bioconversion products were different
between n−3 and n−6 PUFA. Furthermore, strain ALA2 placed hydroxy groups and cyclic structures at the same position from the
ω-terminal despite the number of carbons in the chain and the double bonds in the PUFA. 相似文献
11.
13C Nuclear magnetic resonance (NMR) signals in several fatty compounds with allylic mono- and dihydroxy groups were assigned
by comparing compounds with and without other functional groups (allylic hydroxy, carboxylic acid, respectively, methyl ester
at C1). The simple13C NMR spectra of hydroxylated compounds derived from symmetrical alkenes are particularly useful in making assignments. The
compounds whose signals were partially assigned are 8-hydroxy-9(E)-octadecenoic acid, 11-hydroxy-9(E)-octadecenoic acid, 8, 11-dihydroxy-9(E)-octadecenoic acid, 9(E)-octadecen-8-ol, and 9(E)-octadecene-8, 11-diol. The present evaluation can be used for assigning signals in other fatty compounds. 相似文献
12.
The present paper describes the identification of two stable end products of α-tocopherol oxidation that were previously detected
among the products of the reaction of α-tocopherol with superoxide anion (O
2
−
) under aprotic conditions. One compound, previously designated compound A, was identified astrans-7-hydroxy-trans-8,8a-epoxy-α-tocopherone, and the other, designated compound B, was identified ascis-7-hydroxy-cis-8,8a-epoxy-α-tocopherone. It was also observed that under protic conditions (10% water in acetonitrile) the reaction of α-tocopherol
with O
2
−
did not produce compounds A and B, but rather α-tocopheryl quinone, α-tocopherol dimer, α-tocopherol dihydroxy dimer, and
the previously designated compound C. Compound C was identified in the present study as α-tocopheryl-quinone-2,3-epoxide. 相似文献
13.
Meadowfoam oil is unusual because over 95% of the fatty acids are 20- and 22-carbon aliphatic acids withcis double bonds located principally at the 5- and/or 13-position. Since little information is available on the metabolism of
the 5c−20∶1 and 5c,13c−22∶2 fatty acids, an exploratory study in mice was conducted to investigate the metabolism of purified samples of the free
fatty acids isolated from meadowfoam oil, and to determine the effect of meadowfoam oil on weight gain and tissue lipid composition.
Mice fed diets containing 5% by wt of the purified 5c−20∶1 or 5c,13c−22∶2 for 6 days exhibited no apparent physiological problems. Total liver lipids from mice fed the purified fatty acid diets
contained mean values of 2.0% 5c−20∶1 and 2.1% 5c,13c−22∶2; total heart lipids contained 1.7% 5c−20∶1 and 10.7% 5c,13c−22∶2. Liver total phospholipids from mice fed a 5% meadowfoam oil diet for 19 wk contained 1.4% 5c−20∶1 and 1.9% 5c,13c−22∶2. There was no evidence of desaturation, elongation or retroconversion. Weight gain for mice fed the meadowfoam oil diet
for 19 wk was similar to mice fed corn oil, and was higher than for mice fed hydrogenated cottonseed oil. Considering the
high 5c−20∶1 and 5c,13c−22∶2 content of the diets, the percentages of these fatty acids in mouse tissue lipids from both the short- and long-term
studies were low. Weight gain was surprisingly good since the meadowfoam oil diet was essential fatty acid-deficient. Results
of this initial investigation suggest that the 5c−20∶1 and 5c,13c−22∶2 fatty acids were utilized primarily for energy. In the short-term study, these fatty acids did not produce toxic effects
or cause metabolic problems.
The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of
Agriculture over other firms or similar products not mentioned. 相似文献
14.
Hervé C. Gérard Robert A. Moreau William F. Fett Stanley F. Osman 《Journal of the American Oil Chemists' Society》1992,69(4):301-304
A new high-performance liquid chromatography technique with an evaporative light-scattering detector (ELSD) has been developed
for the separation and quantitative analysis of hydroxy and epoxy fatty acids. This method employs a gradual binary gradient
(hexane/isopropanol) and ELSD detection. The minimum limit of detection is about 1 μg and ratio of mass to signal is essentially
linear in the range of 10 to 200 μg. This high-performance liquid chromatography (HPLC) technique is able to separate various
positional isomers of mono-hydroxy and dihydroxy fatty acids and can also discriminate between monohydroxy, epoxy, epoxyhydroxy,
dihydroxy and trihydroxy fatty acids. 相似文献
15.
A group of unusual triglycerides, in which one of the acyl groups is a vicinal dihydroxy acid with one of the hydroxyl groups
acetylated, has been isolated fromCardamine impatiens L. (Cruciferae) seed oil. Hydrolysis of these triglycerides with castor bean lipase facilitated isolation and identification
of a mixture of C18, C20, C22, and C24 hydroxy acetoxy fatty acids. Pancreatic lipase hydrolysis data revealed that these monoacetylated dihydroxy acid residues
are esterified exclusively with one of the α-positions of the glycerol moiety. The remaining acyl groups are comprised of
ordinary C18 unsaturated acids (which occupy 98% of the β-position), palmitic acid, and C20, C22, and C24 monoenoic fatty acids.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
16.
The phospholipids of the spongeStrongylophora durissima were analyzed. The major phospholipids present were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine
(PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). The major fatty acid components of the phospholipids consisted
of short chain (C14−C19) and very long chain (C25−C30) “Demospongic” acids. Three novel branched Δ5 monounsaturated acids,Z-19-methyl-5-pentacosenoic,Z-19-methyl-5-hexacosenoic andZ-19-methyl-5-heptacosenoic acids were encountered in the sponge. The 3-saturated counterparts of these compounds, 19-methylpentacosanoic,
19-methylhexacosanoic and 19-methylheptacosanoic acids, as well as 19-methylpentacosanoic and 20-methyloctacosanoic acids
also are hitherto undescribed acids present in the sponge. Trace amounts of 2 very long chain acids also were detected and
their structures tentatively assigned as 19,21-dimethylheptacosanoic and 20,22-dimethyloctacosanoic acids. The distribution
of these fatty acids according to phospholipid head groups also was described. 相似文献
17.
This study concerns the preparation and evaluation of nonionic surfactants prepared from polyethylene glycol (PEG) esters
of castor oil fatty acid, a source of hydroxy fatty acid. A lipase-catalyzed esterification reaction has been employed to
prepare PEG esters of hydroxy acid to overcome problems associated with chemical processes. Castor oil fatty acid (85% ricinoleic
acid) was mixed with PEG of different molecular weight. Rhizomucor miehei lipase was added as catalyst (10% level) and the reaction was continued at 60°C under 2 mm Hg pressure for 360 min. Conversion
of PEG to esters was in the range of 86–94%, depending on the molecular size of PEG. The products were isolated and examined
for surface activity by surface tension measurement. Surface tension values measured at 25°C were about 36–37 dynes/cm. 相似文献
18.
Hary Razafindralambo Philippe Thonart Michel Paquox 《Journal of surfactants and detergents》2004,7(1):41-46
A homologous series of surfactins containing β-hydroxy fatty acids having 13, 14, or 15 carbon atoms were isolated from the
supernatant of Bacillus subtilis strain S499 cultures. Their surface-active properties at the air-water interface were then evaluated. Dynamic surface tension
data were analyzed by the relaxation function γt=γm+(γo−γm)/[1+(t/t*)n]. Based on various parameters t*, n, vmax, γm calculated from this equation, the dynamic surface properties of surfactin were found to depend on both bulk concentration
and hydrophobic character of the alkyl chain. At low concentrations of surfactin, the dynamic surface tension (γd) decreased with increasing carbon atom number of the surfactin alkyl chain (n=13 to 15). However, at high concentrations, the maximum decrease of 41-4 was achieved by surfactin-C14. In contrast, more strongly hydrophobic alkyl chains in surfactins always enhanced their ability in reducing the equilibrium
surface tensions and their aptitude in forming micelles. 相似文献
19.
Roger Wayne Miller F. R. Earle I. A. Wolff Quentin Jones 《Journal of the American Oil Chemists' Society》1965,42(10):817-821
Seed from additional species of Cruciferae have been analyzed for crude protein, oil and fatty acids in the oil. Oils were
like those reported earlier from other crucifers, except forCardamine impatiens which is unique among known seed oils because it contains some 25% dihydroxy acids. Erucic acid is present (0.3–55%) in about
three-fourths of the 102 samples. Eicosenoic acid is a major constituent (32–53%) in four species and monohydroxy acids (45–72%)
in another four. Linolenic acid occurs (2–66%) in oil of all species.
Presented at the AOCS meeting in Chicago, Ill., October 11–14, 1964.
A laboratory of the No. Utiliz. Res. and Dev. Div., ARS, USDA.
ARS, USDA. 相似文献
20.
M. Safar D. Bertrand P. Robert M. F. Devaux C. Genot 《Journal of the American Oil Chemists' Society》1994,71(4):371-377
The combination of attenuated total reflectance (ATR) and mid-infrared spectroscopy (MIRS) with statistical multidimensional
techniques made it possible to extract relevant information from MIR spectra of lipid-rich food products. Wavenumber assignments
for typical functional groups in fatty acids were made for standard fatty acids: Absorption bands around 1745 cm−1, 2853 cm−1, 2954 cm−1, 3005 cm−1, 966 cm−1, 3450 cm−1 and 1640 cm−1 are due to absorption of the carbonyl group, C−H stretch, =CH double bonds of lipids and O−H of lipids, respectively. In
lipid-rich food products, some bands are modified. Water strongly absorbs in the region of 3600–3000 cm−1 and at 1650 cm−1 in butters and margarines, allowing one to rapidly differentiate the foods as function of their water content. Principal
component analysis was used to emphasize the differences between spectra and to rapidly classify 27 commercial samples of
oils, butters and margarines. As the MIR spectra contain information about carbonyl groups and double bonds, the foods were
classified with ATR-MIR, in agreement with their degree of esterification and their degree of unsaturation as determined from
gas-liquid chromatography analysis. However, it was difficult to differentiate the studied food products in terms of their
average chainlength. 相似文献