Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Lipids ; 39(6): 571-6, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15554157

RESUMO

The occurrence of petroselinic acid (18:1delta6cis) in seed oils was believed to be limited to the Umbelliferae or Apiaceae, and a few other members of the Umbelliflorae. A major occurrence of petroselinic acid outside the Umbelliflorae must therefore be regarded as highly unusual and surprising. The seed oil of Geranium sanguineum, a member of the family Geraniaceae, has now been found to contain petroselinic and vernolic acids as major FA in its seed oil TAG. These unusual FA have not been reported previously as constituents of Geraniaceae seed oils. The structure and composition of the seed oil FA from G. sanguineum were determined by combined use of chromatographic (TLC, capillary GLC) and spectroscopic (IR, GC-MS) techniques. The double-bond position in petroselinic acid was located unambiguously by the characteristic mass fragmentation of its dimethyldisulfide (DMDS) adduct. The epoxy FA was identified as vernolic acid by co-chromatography and by the mass fragments formed during GC-MS of the products of the epoxy ring-opening reaction with BF3 in methanol.


Assuntos
Compostos de Epóxi/isolamento & purificação , Geranium/química , Ácidos Oleicos/isolamento & purificação , Óleos de Plantas/química , Cromatografia , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas , Sementes/química , Análise Espectral
2.
Lipids ; 38(11): 1173-8, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14733363

RESUMO

Seeds of Androsace septentrionalis of the genus Androsace (tribus Primuleae) from the plant family Primulaceae were studied for their oil content and FA composition. The seed oil of A. septentrionalis was found to contain two unusual FA rarely occurring in plants: 11-cis-hexadecenoic acid (16:1delta11c or 16:1n-5) and 9-cis,12-cis-hexadecadienoic acid (16:2delta9c,12c or 16:2n-4). It also contained an unusually high amount (21.4%) of 9-cis-hexadecenoic acid (palmitoleic acid; 16:1delta9c or 16:1n-7), i.e., at a level higher than that of oleic acid, in addition to common FA. Compared with most plant seed oils, at 3.8% the level of 18:1delta11c (or 18:1n-7) also was elevated. The nonidentity of the Androsace 16:2-acid with the 16:2-acid, which is very typical for Ranunculus spp., as well as its identity with the 16:2-acid typically found in Asclepiadaceae was established by co-chromatography. The structure and composition of the constituent FA of A. septentrionalis were also determined by various chromatographic methods (TLC, Ag+-TLC, capillary GLC) and spectroscopic methods (IR, GC-MS). The significant deviation of the Androsace FA pattern from that of other Primuleae, indicating a separate phylogenetic position of Androsace, is discussed.


Assuntos
Ácidos Palmíticos/metabolismo , Primulaceae/metabolismo , Sementes/metabolismo , Cromatografia Gasosa , Isomerismo , Espectrometria de Massas
3.
Lipids ; 36(5): 439-51, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11432455

RESUMO

Following our previous review on Pinus spp. seed fatty acid (FA) compositions, we recapitulate here the seed FA compositions of Larix (larch), Picea (spruce), and Pseudotsuga (Douglas fir) spp. Numerous seed FA compositions not described earlier are included. Approximately 40% of all Picea taxa and one-third of Larix taxa have been analyzed so far for their seed FA compositions. Qualitatively, the seed FA compositions in the three genera studied here are the same as in Pinus spp., including in particular the same delta5-olefinic acids. However, they display a considerably lower variability in Larix and Picea spp. than in Pinus spp. An assessment of geographical variations in the seed FA composition of P. abies was made, and intraspecific dissimilarities in this species were found to be of considerably smaller amplitude than interspecific dissimilarities among other Picea species. This observation supports the use of seed FA compositions as chemotaxonomic markers, as they practically do not depend on edaphic or climatic conditions. This also shows that Picea spp. are coherently united as a group by their seed FA compositions. This also holds for Larix spp. Despite a close resemblance between Picea and Larix spp. seed FA compositions, principal component analysis indicates that the minor differences in seed FA compositions between the two genera are sufficient to allow a clear-cut individualization of the two genera. In both cases, the main FA is linoleic acid (slightly less than one-half of total FA), followed by pinolenic (5,9,12-18:3) and oleic acids. A maximum of 34% of total delta5-olefinic acids is reached in L. sibirica seeds, which appears to be the highest value found in Pinaceae seed FA. This apparent limit is discussed in terms of regio- and stereospecific distribution of delta5-olefinic acids in seed triacylglycerols. Regarding the single species of Pseudotsuga analyzed so far (P. menziesii), its seed FA composition is quite distinct from that of the other two genera, and in particular, it contains 1.2% of 14-methylhexadecanoic (anteiso-17:0) acid. In the three genera studied here, as well as in most Pinus spp., the C18 delta5-olefinic acids (5,9-18:2 and 5,9,12-18:3 acids) are present in considerably higher amounts than the C20 delta5-olefinic acids (5,11-20:2 and 5,11,14-20:3 acids).


Assuntos
Ácidos Graxos/análise , Pinaceae/química , Pinaceae/classificação , Sementes/química , Biomarcadores/análise , Biomarcadores/química , Cromatografia Gasosa , Ácidos Graxos/química , Filogenia , Óleos de Plantas/química
4.
Lipids ; 34(8): 855-64, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10529097

RESUMO

The fatty acid compositions of the seed lipids from four Ephedra species, E. nevadensis, E. viridis, E. przewalskii, and E. gerardiana (four gymnosperm species belonging to the Cycadophytes), have been established with an emphasis on delta5-unsaturated polymethylene-interrupted fatty acids (delta5-UPIFA). Mass spectrometry of the picolinyl ester derivatives allowed characterization of 5,9- and 5,11-18:2; 5,9,12-18:3; 5,9,12,15-18:4; 5,11-20:2; 5,11,14-20:3; and 5,11,14,17-20:4 acids. Delta5-UPIFA with a delta11-ethylenic bond (mostly C20 acids) were in higher proportions than delta5-UPIFA with a delta9 double bond (exclusively C18 acids) in all species. The total delta5-UPIFA content was 17-31% of the total fatty acids, with 5,11,14-20:3 and 5,11,14,17-20:4 acids being the principal delta5-UPIFA isomers. The relatively high level of cis-vaccenic (11-18:1) acid found in Ephedra spp. seeds, the presence of its delta5-desaturation product, 5,11-18:2 acid (proposed trivial name: ephedrenic acid), and of its elongation product, 13-20:1 acid, were previously shown to occur in a single other species, Ginkgo biloba, among the approximately 170 gymnosperm species analyzed so far. Consequently, Ephedraceae and Coniferophytes (including Ginkgoatae), which have evolved separately since the Devonian period (approximately 300 million yr ago), have kept in common the ability to synthesize C18 and C20 delta5-UPIFA. We postulate the existence of two delta5-desaturases in gymnosperm seeds, one possibly specific for unsaturated acids with a delta9-ethylenic bond, and the other possibly specific for unsaturated acids with a delta11-ethylenic bond. Alternatively, the delta5-desaturases might be specific for the chain length with C18 unsaturated acids on the one hand and C20 unsaturated acids on the other hand. The resulting hypothetical pathways for the biosynthesis of delta5-UPIFA in gymnosperm seeds are only distinguished by the position of 11-18:1 acid. Moreover, 13C nuclear magnetic resonance spectroscopy of the seed oil from two Ephedra species has shown that delta5-UPIFA are essentially excluded from the internal position of triacylglycerols, a characteristic common to all of the Coniferophytes analyzed so far (more than 30 species), with the possibility of an exclusive esterification at the sn-3 position. This structural feature would also date back to the Devonian period, but might have been lost in those rare angiosperm species containing delta5-UPIFA.


Assuntos
Alcenos/química , Sementes/química , Triglicerídeos/química , Isótopos de Carbono , Cycadopsida/química , Dessaturase de Ácido Graxo Delta-5 , Evolução Molecular , Ácidos Graxos Dessaturases , Ácidos Graxos Insaturados/análise , Cromatografia Gasosa-Espectrometria de Massas , Lipídeos/química , Espectroscopia de Ressonância Magnética , Filogenia , Óleos de Plantas/química
5.
Nahrung ; 43(4): 228-32, 1999 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-10481819

RESUMO

Since several years, sea buckthorn and sea buckthorn oils are booming in China, Russia and Central Asia. The background of this development is described and the different species and varieties of sea buckthorn are mentioned. The two different oils obtained from sea buckthorn (pulp oil and seed oil) and their composition is discussed. The use of sea buckthorn and its oils for medical and pharmaceutical purposes has its roots in ancient Tibet. The various "health claims", particularly by Russian and Chinese medical authorities, could not be discussed here. However, a number of recent papers are quoted here without further comment.


Assuntos
Óleos de Plantas/uso terapêutico , Plantas Medicinais , Plantas Tóxicas , Rhamnus/química , Agricultura , Animais , Ásia , China , Humanos , Óleos de Plantas/química , Óleos de Plantas/farmacologia
6.
Lipids ; 34(5): 525-9, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10380126

RESUMO

Seeds of Youngia tenuicaulis and other species from the plant family Compositae (Asteraceae) were studied for their oil content and fatty acid composition. The seed oil of Y. tenuicaulis growing in Mongolia was found to contain 5.6% gamma-linolenic acid (18:3delta6cis,9cis,12cis) in addition to common fatty acids. The oil was analyzed using chromatographic [capillary gas-liquid chromatography (GLC), thin-layer chromatography] and spectroscopic (infrared, gas chromatography-mass spectrometry) techniques. Seed oil fatty acids of Saussurea amara (containing gamma-linolenic acid) and of Arctium minus (containing 18:3delta3trans,9cis,12cis), as well as delta5cis- and delta5trans-18:3 were used as GLC reference substances. The evolution in this plant family of a large number of different 18:3 acids as well as the corresponding evolution of unusual desaturases should be investigated. On the other hand, the delta6cis-desaturase required for the biosynthesis of gamma-linolenic acid may have evolved independently several times in unrelated families of the plant kingdom.


Assuntos
Asteraceae/química , Óleos de Plantas/química , Sementes/química , Ácido gama-Linolênico/análise , Cromatografia Gasosa , Espectrofotometria Ultravioleta
7.
Lipids ; 31(2): 201-5, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8835409

RESUMO

The current discussion on "renewable resources", and the possibility of gene transfer into rapeseed, has led to many investigations into the biosynthetic pathways leading to industrially useful fatty acids. The various tribes and genera of the plant family Ranunculaceae contain a large variety of unusual fatty acids. Seed fatty acid patterns differ considerably from genus to genus and are chemotaxonomically significant indicators. Eranthis seed oil has now been found to contain a fatty acid pattern that deviates significantly from the eleven different fatty acid patterns that had been described in this plant family. The main fatty acid (up to 57%) is 13-cis, 16-cis-docosadienoic acid. Other, minor fatty acids found are delta 5-cismonoenoic, -dienoic, and -trienoic fatty acids that had already been reported to be constituents of the genus-specific seed oil fatty acid patterns of various genera from this plant family. Capillary gas-liquid chromatographic retention data indicate that 22:3 delta 5 cis, 13 cis, 16 cis is probably also present. Seed fatty acid chemotaxonomic evidence thus points to a different position of Eranthis within the tribes of this plant family. These findings again indicate that the plant family Ranunculaceae would be an ideal object to study fatty acid biosynthesis and phylogenetic evolution, because in other genera of this family other types of desaturation and chain elongation mechanisms predominate.


Assuntos
Ácidos Graxos/análise , Óleos de Plantas/análise , Evolução Biológica , Cromatografia Gasosa , Ácidos Graxos/biossíntese , Ácidos Graxos Insaturados/análise , Filogenia , Sementes/metabolismo
8.
J Parasitol ; 81(4): 501-4, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7623188

RESUMO

An active enzyme system for fatty acid chain elongation exists in Paratenuisentis ambiguus (Acanthocephala), which elongates [1-14C]palmitic acid consecutively to stearic and arachidic acid. Highest specific activity of radioactive elongation products was detected in phosphatidylethanolamines that seem to play an outstanding role as acceptors of saturated long-chain and very long-chain fatty acids. In contrast, incubation of P. ambiguus with monounsaturated [1-14C]oleic acid under similar conditions led to small proportions of labeled eicosenoic acid only. Analysis of the fatty acid pattern and stereospecific distribution at the glycerol backbone of phospholipids revealed that saturated acyl moieties with 18, 20, and 22 carbon atoms were esterified almost exclusively in the sn-1 position of phosphatidylethanolamines and -cholines, whereas polyunsaturated fatty acids were found predominantly in the sn-2 position of these phospholipids. From these results it may be concluded that the parasite channels saturated long-chain and very long-chain fatty acids predominantly to the sn-1 position of phospholipids in order to compensate for increasing membrane fluidity caused by the incorporation of high proportions of polyunsaturated fatty acids of aquatic feed.


Assuntos
Acantocéfalos/metabolismo , Enguias/parasitologia , Ácidos Graxos/química , Doenças dos Peixes/parasitologia , Helmintíase Animal , Animais , Helmintíase/parasitologia , Intestinos/parasitologia , Fosfatidilcolinas/química , Fosfatidiletanolaminas/química , Estereoisomerismo
9.
Parasitol Res ; 81(6): 522-6, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7567912

RESUMO

The fatty acid fingerprints of total lipid extracts from the four fish parasites Acanthocephalus lucii, Neoechinorhynchus rutili, Paratenuisentis ambiguus, and Pomphorhynchus laevis were investigated by capillary gas-liquid chromatography (GLC). The fatty acid patterns of the parasites were compared with those of their respective host tissue, viz., intestinal tract tissue of infected perch, brown trout, eel, and chub. The highly complex gas chromatograms revealed significant differences not only between parasite and host tissue but also between the parasites themselves. For instance, all the parasites contained much more eicosapentaenoic acid (20:5n-3) than did the respective fish intestinal tissue. Differences were also observed between the presoma and metasoma of Pomphorhynchus laevis.


Assuntos
Acantocéfalos/química , Ácidos Graxos/análise , Peixes/parasitologia , Intestinos/química , Animais , Cromatografia Gasosa , Especificidade da Espécie
10.
Lipids ; 29(6): 421-7, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8090063

RESUMO

The sterol composition of free sterol and steryl ester fractions of the fish parasite Paratenuisentis ambiguus was determined. In addition, the fatty acid composition of various neutral lipid classes, i.e., wax esters, steryl esters, triacylglycerols and free fatty acids, as well as the composition of the 1-O-alkyl moieties of total ether glycerolipids of the parasite, were investigated. The results of these studies were compared with those obtained on the intestinal tract tissue of its host, the eel (Anguilla anguilla). Cholesterol is the major sterol in both P. ambiguus and A. anguilla. However, the sterols of P. ambiguus contain high proportions (> 20%) of other sterols, such as campesterol and various dehydrosterols. [e.g., 7-dehydrocholesterol and cholesta-5,22(E)-dienol]. The presence of these minor sterols agrees with the known biotransformations of exogenous sterols in various helminths. Considerable differences are found in the fatty acid composition of neutral lipid fractions, as well as the total lipid extract from the endoparasite as compared to the host tissue. In particular, eicosapentaenoic acid (20:5n-3), other polyunsaturated fatty acids, such as 20:4n-6, 22:5n-3 and 22:6n-3, as well as long-chain saturated fatty acids, such as 20:0, are generally enriched in the neutral lipid fractions of the parasite as compared to those of infected eel intestine.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Acantocéfalos/química , Anguilla/parasitologia , Ácidos Graxos/análise , Lipídeos/análise , Esteróis/análise , Anguilla/metabolismo , Animais , Colesterol/análise , Ácido Eicosapentaenoico/análise , Éteres/análise , Ácidos Graxos não Esterificados/análise , Cromatografia Gasosa-Espectrometria de Massas , Glicolipídeos/análise , Intestinos/química , Intestinos/parasitologia , Triglicerídeos/análise
12.
Z Lebensm Unters Forsch ; 169(5): 335-8, 1979 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-516918

RESUMO

The isomeric food dyes E 110 and E 111 can be separated by ion pair partition HPLC on reversed-phase columns. The isomer E 111 - no longer permitted in Germany - can thus be determined in dye and food samples. The determination of E 110, E 111, and E 124 in fish samples (canned saithe) is described.


Assuntos
Compostos Azo/análise , Corantes de Alimentos/análise , Carne/análise , Naftalenossulfonatos/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Peixes , Alemanha Ocidental , Isomerismo
13.
Z Lebensm Unters Forsch ; 169(3): 155-8, 1979 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-506487

RESUMO

New regulations limit the amount of diglycerol that may be present in partial glycerides used as food emulsifiers. Dimeric glycerol can be easily determined by HPLC on silica columns using acetonitrile: water partition and RI detection. Results for free diglycerol and total diglycerol obtained with a number of monoglyceride samples are given.


Assuntos
Diglicerídeos/análise , Glicerídeos/análise , Glicerol/análise , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos
15.
J Chromatogr ; 145(2): 195-202, 1978 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-649714

RESUMO

A technique is described for the high-pressure liquid chromatographic (HPLC) analysis of sebum lipid classes. The lipid present in sebum are separated by gradient elution HPLC from a microparticulate silica column and detected using a moving-wire detector. The system described can be linked to a computer. Quantitation can be carried out by comparing peak areas obtained with those of an internal standard. Peak trapping for further investigations of the separated components, for example by gas chromatography-mass spectrometry, is very easy. Sebum lipids are separated into the following lipid classes: hydrocarbons and squalene, cholesterol esters and wax esters, fatty acids as their methyl esters, triglycerides, 1,3-diglycerides, 1,2-diglycerides, free cholesterol, monoglycerides and other polar materials. Besides to sebum, the method has been successfully applied to other lipid mixtures, such as serum lipids. Examples of other applications are shown.


Assuntos
Lipídeos/análise , Sebo/análise , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Lipídeos/sangue , Lipídeos/classificação , Solventes
16.
J Chromatogr ; 139(1): 61-8, 1977 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-893616

RESUMO

A high-performance liquid chromatographic (HPLC) technique for the analysis of partial glyceride mixtures is described and some technical details are discussed. Gradient elution HPLC with a "moving-wire" detector linked to a computer is used for quantitative analysis. The method described has been applied to the analysis of mono-, di- and triglyceride mixtures, food emulsifiers, certain seed fats, and technical products such as polymer additives.


Assuntos
Glicerídeos/análise , Cromatografia Líquida de Alta Pressão/métodos , Diglicerídeos/análise , Aditivos Alimentares/análise , Lipídeos/análise , Sementes/análise , Triglicerídeos/análise
17.
J Chromatogr Sci ; 13(10): 454-61, 1975 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1184712

RESUMO

Published applications of moving-wire detectors and other transport flame ionization detectors for the liquid chromatography of fats and oleochemical are briefly reviewed. The usefulness of this detector is illustrated by a number of examples taken from our own work at the Unilever Forschungsgesellschaft Hamburg. The chromatograms shown were chosen in which a way as to give an idea of how broad a range of applications may be covered by this approach.


Assuntos
Cromatografia Líquida/instrumentação , Gorduras/análise , Ácidos Graxos/análise , Absorção , Lipídeos/análise , Métodos , Solventes , Espectrofotometria Ultravioleta
20.
J Chromatogr ; 22(2): 431-45, 1966 May.
Artigo em Alemão | MEDLINE | ID: mdl-23045743

RESUMO

A method for the electrophoresis of inorganic radioactive cations on cellulose acetate (Cellogel) is described. The advantages of this technique are illustrated by numerous examples. Separations of the rare earth metals, the alkaline earths and fission products are mentioned particularly.


Assuntos
Celulose/análogos & derivados , Eletroforese/métodos , Radioisótopos/química , Celulose/química , Reprodutibilidade dos Testes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...