共查询到20条相似文献,搜索用时 31 毫秒
1.
Kuksis A. Myher J. J. Marai L. Little J. A. McArthur R. G. Roncari D. A. K. 《Lipids》1986,21(6):371-377
The bulk of the plasma plant sterol in phytosterolemia occurs in the esterified form and is carried mostly in the low and
high density lipoproteins. We have determined the fatty acid composition of the individual plasma steryl esters from a newly
discovered subject with phytosterolemia and xanthomatosis. For this purpose the intact steryl esters were subject to high
temperature gas liquid chromatography (GLC) on a polar capillary column, which separated the major esters on the basis of
molecular weight and degree of unsaturation of the fatty acids. The saturated and unsaturated sterols esterified to saturated,
monoenoic, dienoic and tetraenoic fatty acids were identified by GLC analysis of the sterol moieties of the corresponding
AgNO3-TLC fractions of the steryl esters. The GLC results were confirmed by reversed phase high performance liquid chromatography
combined with mass spectrometry via direct liquid inlet interface. It was found that, in general, each fatty acid was esterified
to the same complement of sterols, and that the esterified sterols possessed a composition comparable to that of the free
plasma sterols, which was comprised of about 75% cholesterol, 6% campesterol, 4% 22,23-dihydrobrassicasterol and 15% β-sitosterol.
The fatty acid composition of the steryl esters differed from that of the 2-position of the plasma phosphatidylcholines, which
contained significantly less palmitic and oleic and more linoleic acid. On the basis of these results and a review of the
literature it is suggested that the plasma cholesteryl and plant steryl esters in phytosterolemia originate from both synthesis
in plasma via the lecithin-cholesterol acyltransferase and synthesis in tissues via the acylCoA-cholesterol acyltransferase. 相似文献
2.
The low temperature crystallization technique for the enrichment of “minor” components, such as sterols and sterol esters,
from vegetable oils was applied to low erucic acid rapeseed oils. The recovery of free sterols and sterol esters was estimated
by use of14C-cholesterol and14C-cholesterol oleate. 80% of the free sterols and 45% of the sterol esters were recovered in the liquid fraction, while in
two studies total recoveries were 95% and 99%, respectively. This technique showed some selectivity toward the sterol bound
fatty acids when compared to direct preparative thin layer chromatography (TLC) of the crude oil. Gas liquid chromatography
(GLC) analysis of the free and esterified sterols as TMS-derivatives showed very little selectivity in the enrichment procedure.
The fatty acid patterns of the sterol esters demonstrated, however, a preference in the liquid fraction for those sterol esters
which have a high linoleic and linolenic acid content. The content of free sterols was 0.3–0.4% and that of sterol esters
0.7–1.2% of the rapeseed oils in both winter and summer types of low erucic acid rapeseed (Brassica napus) when the lipid classes were isolated by direct preparative TLC of the oils. The free sterols in the seven cultivars or breeding
lines analyzed were composed of 44–55% sitosterol, 27–36% campesterol, 17–21% brassicasterol, and a trace of cholesterol.
The esterified sterols were 47–57% sitosterol, 36–44% campesterol, 6–9% brassicasterol, and traces of cholesterol and Δ5-avenasterol.
The fatty acid patterns of these esters were characterized by ca. 30% oleic acid and ca. 50% linoleic acid, whereas these
acids constitute 60% and 20%, respectively, of the total fatty acids in the oil. Little or no variation in sterol and sterol
ester patterns with locality within Sweden was observed for the one cultivar of summer rapeseed investigated by the low temperature
crystallization technique. 相似文献
3.
Comparative studies of the sterol composition of four sterol fractions, vis., free sterols, sterol esters, sterol glucosides
and esterified sterol glucosides, were conducted on the juice sacs of six varieties of oranges and two tangor varieties. The
sterols quantified in each fraction were β-sitosterol, campesterol, stigmasterol, cholesterol, 24-ethylidene cholesterol,
brassicasterol and 24-methylene cholesterol. Each variety showed its own intrinsic composition for these sterols in the four
sterol fractions.
So. Market. Nutr. Res. Div., ARS, USDA. 相似文献
4.
The content and composition of sterols and sterol esters in sunflower and poppy seed oils 总被引:1,自引:0,他引:1
Anna Johansson 《Lipids》1979,14(3):285-291
The composition and proportion of free sterols and sterol esters in crude sunflower and poppy seed oils were determined, using
preparative thin layer chromatography followed by gas chromatography with cholesterol as an internal standard. Free sterols
and sterol esters were also isolated in a liquid fraction obtained by low temperature crystallization (−80 C) of the oils
and enriched with minor lipid classes. This enrichment procedure provided a liquid fraction suitable for studies of minor
components in the oils. However, selectivity towards sterol esters was observed since sterols esterified to very long chain
fatty acids (C20–C24) were preferentially retained in the precipitate. The proportions of free and esterified sterols were found to be 0.34 and
0.28%, respectively, in the sunflower oil, whereas the corresponding figures for poppy seed oil were 0.33% and 0.05%. Sunflower
oil was characterized by a relatively high percentage of Δ7-sterols, preferentially obtained in the esterified fraction, and
by very long chain saturated fatty acids of sterol esters. The sterols in poppy seed oil were composed almost entirely of
campesterol, stigmasterol, sitosterol and Δ5-avenasterol, although their percentage distributions were remarkably different
in the free and esterified fraction. 相似文献
5.
Four Canadian varieties of potatoes were examined for their lipid composition. Lipids, extracted with chloroformmethanol,
were shown by TLC and column chromatography to consist of 16.5% neutral lipids, 45.5% phospholipids and 38.1% glycolipids.
Among the phospholipids and glycolipids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, the galactolipids
and the sterol glucosides were the major lipids. The predominant fatty acids were palmitic (19.5%), linoleic (44.8%) and linolenic
(30.4%, in Kennebec). Analyses of the fatty acids of stored potatoes showed a marked decrease in linoleic acid and an increase
in linolenic acid, in the Irish Cobbler and Sebago potatoes. β-sitosterol comprised 85.0% of total sterols. Nearly half of
the carotenoids was lutein (xanthophyll), the others being α-carotene, β-carotene, an unidentified pigment and lutein epoxide.
Contribution No. 101 of the Food Research Institute, Canada Department of Agriculture. 相似文献
6.
Sterol lipids of cocoa butter (cocoa beansLome Tongo) were fractionated into free sterols, steryl esters (SE), steryl glucosides and acylated steryl glucosides (ASG). 4-Desmethyl,
4-methyl and 4,4′-dimethyl sterols or triterpene alcohols, which were isolated as free sterols or which resulted from hydrolysis,
were determined by thin layer chromatography-flame ionization detection and identified by gas chromatography and combined
gas chromatography-mass spectroscopy. Free sterols comprise the main sterol fraction in cocoa butter. Esterified sterols amount
to 11.5% of total sterols and glucosidic sterols to 16.3%. Fatty acids and D-glucose from hydrolysis of esters and glucosides
were analyzed. The fatty acids of SE and ASG are richer in unsaturated fatty acids than cocoa butter total fatty acids. 相似文献
7.
Capillary gas liquid chromatography analyses were conducted on free and esterified sterol fractions of cotton (Gossypium hirsutum cv. Stoneville 213) floral buds and anthers. The free sterols of both cotton buds and anthers consist mainly of the common
plant sterols sitosterol, stigmasterol and 24ζ-methylcholest-5-en-3β-ol. The composition of esterified sterols of cotton buds
and anthers were similar, and consisted of pollinastanol, 31-norcycloartanol, cycloartenol, 31-norcycloartenol, 24-dehydropolinastanol
and sitosterol. Desmosterol was also present in both the free and esterified sterols of anthers. The identities of the sterols
were confirmed by gas chromatography-mass spectrometry analyses. Esterified sterols accounted for 46.7 and 88.7% of total
sterols of cotton bud and anthers, respectively. The ratio of esterified sterol to free sterol per gram of tissue is about
8∶1 in anthers. The Δ5-sterols of the esterified sterols of cotton buds and anthers account for only 17 and 9.2% of the total sterols, respectively. 相似文献
8.
The Effect of processing on the content and composition of free sterols and sterol esters in soybean oil 总被引:1,自引:0,他引:1
The content and composition of free sterols and sterol esters in crude soybean oil and in oils from different stages of two
continuous refining systems were determined. The sterols were isolated by preparative thin layer chromatography and analyzed
by gas chromatography with cholesterol as an internal standard. The free sterols in one of the degummed oils amounted to 3.1
mg/g and were diminished to 1.8 mg/g oil by the De Laval Short-Mix refining process. The content of free sterols of the other
degummed oil was reduced from 3.4 to 1.6 mg/g oil by the Zenith process. The greatest reduction of sterol content was caused
by the treatment with bleaching earth. The sterol esters accounted for 0.6 mg/g of the degummed oil, and only very small changes
were observed during the processes. However, changes in the composition of fatty acids of the sterol esters were found. These
changes might indicate a selective deacylation of sterol esters or an interesterification during the refining processes. The
composition of sterols in free and esterified form were different. Campesterol, stigmasterol and sitosterol were obtained
in both free and esterified form, but Δ7 stigmasterol was only found in esterified form. Only small changes in the percentage
distribution of the sterols occurred during the processes.
Present adress Food Technology Division, ALFA-LAVAL,S-14700 Tumba, Sweden 相似文献
9.
V. S. Kamanna N. Chandrasekhara 《European Journal of Lipid Science and Technology》1986,88(4):136-139
Neutral, glyco- and phospholipids of garlic were resolved into their component fractions by thin layer chromatography. Neutral lipids contained considerable quantities of monoglycerides (18.5%), diglycerides (14.2%), sterols (16.3%) and triglycerides (41.5%) respectively. The phospholipid fraction was rich in phosphatidyl choline (23.5%), phosphatidyl ethanolamine (17.9%), lysophosphatidyl choline (11.8%) and lysophosphatidyl ethanolamine (8.2%). Digalactosyl diglyceride (10.1%), sterol glycoside (15.6%), cerebrosides (8.1%), acylsterol glycoside (38.6%) and monogalactosyl diglyceride (22.5%) were the major components of the glycolipids of garlic. Lauric, myristic, palmitic and linoleic acids constituted the major fatty acids of monoglycerides, diglycerides and free fatty acid fractions whereas palmitic, linoleic and linolenic acids were the major fatty acids of triglycerides. Palmitic and linoleic acids were the major fatty acids of garlic phospholipids. Except the acylsterol glycoside fraction glycolipids were rich in lauric, palmitic, linoleic and linolenic acids; palmitic acid was the only major fatty acid of acylsterol glycosides. 相似文献
10.
The Content and Composition of Total,Free, and Esterified Sterols of Lotus Plumule Oil by GC–MS/FID 下载免费PDF全文
Shuai Chen Yanlan Bi Shangde Sun Jingnan Chen 《Journal of the American Oil Chemists' Society》2017,94(3):363-373
This study investigated the content and composition of total, free, and esterified sterols of three varieties of lotus plumule oil (Hunan lotus, Jiangxi lotus, and Fujian lotus) using GC–MS/FID. The fatty acid composition of sterol fatty acid esters (SFAE) was also analyzed and compared with that of triglycerides. Results showed that total sterol of lotus plumule oil (12.10–14.21 g/100 g) was higher than that of other plant oils (corn germ oil, 1.11 g/100 g; rapeseed oil, 0.78 g/100 g). No significant difference was found among the total sterol contents of the three types of lotus plumule oils (p > 0.05). Most sterol existed in ester forms (81.8–89.1%) rather than in free forms (8.4–10.1%). β‐Sitosterol (71.4–73.4%), and campesterol (6.2–7.5%) were the predominant fractions of free sterols. β‐Sitosterol (41.3–53.7%) and ?5‐avenasterol (27.1–31.1%) were the predominant fractions of esterified sterols, followed by campesterol (12.1–13.0%) and ?7‐avenasterol (3.4–3.7%). Linoleic acid (63.6–65.8%), oleic acid (8.3–10.4%), and behenic acid (9.0–9.9%) were the main fatty acids of SFAE, which were different from those of triglycerides. The results from this study suggest that lotus plumule oil may be a good resource of SFAE and can be used as a supplemental ingredient in functional foods. 相似文献
11.
The fatty acid composition and biosynthesis of fatty acids were studied during early embryogenesis of the toadBufo arenarum Hensel. The ova and stages up to the 6 1/2 day embryo have similar fatty acid compositions, with ca. 70% unsaturated acids.
The eggs and embryo were permeable to acetate and impermeable to palmitic, linoleic, and eicosa-8,11,14-trienoic acid. Labeled
acetate was incorporated by the eggs into the saturated acids-lauric, myristic, palmitic, stearic, arachidic, and behenic-and
into the unsaturated acids-myristoleic, palmitoleic, oleic, and eicosaenoic acids. During segmentation and gastrulation, de
novo biosynthesis of fatty acids increased, desaturation to myristoleic, palmitoleic, and oleic acids was enhanced; and fatty
acids were esterified to triglycerides, phosphatidyl choline, and phosphatidyl ethanolamine. The feeding embryo (11 days)
changed the pattern of incorporation to less incorporation into triglycerides. 相似文献
12.
Compositions of six grades of tall oil pitch (TOP), four of finnish and two of U.S. origin were investigated. The pitch samples
contained 34.6–51.6% free acids, 23.2–37.8% esterified acids, and 25.3–34.4% unsaponifiable neutral compounds. Each of the
above fractions was analyzed by high resolution gas chromatography-mass spectrometry. Approximately 60% of the weight fraction
in TOP consisted of high molecular components of which about half were acidic compounds. The low molecular free acids were
mainly dehydroabietic, abietic, and other resin acids. The esterified acids consisted chiefly of oleic and linoleic acids.
Unsaponifiable fractions were composed of diterpene alcohols, fatty alcohols, sterols, and dehydrated sterols. The alcohol
components were almost completely esterified. 相似文献
13.
Skin surface lipids of the dog 总被引:1,自引:0,他引:1
The skin surface lipid of the dog has been reported to contain a high proportion of diol diesters having a lower mobility
on thin layer chromatography than diesters from other species in spite of containing similar fatty acid and diol components.
In the present study, dog skin surface lipid was separated by preparative thin layer chromatography into sterol esters (42%),
wax diesters (32%), free sterols (9%), polar lipids (7%), and unidentified components (10%). The diesters contained 1,2-diols,
each esterified with one long chain fatty acid and one isovaleric acid moiety. The diols were principally branched chain C21 and C22 compounds while the long chain fatty acids esterified with them were mainly C20 and C21 branched compounds. The fatty acids from the sterol esters were mostly saturated, branched chain C19 to C23, together with 7% of straight chain monoenoic acids, principally C21 and C22. There were only trace amounts of free sterols other than cholesterol, while the esterified sterols contained 96% cholesterol
and 4% lathosterol. 相似文献
14.
Procedures for the large scale isolation of pure triglycerides and fractions rich in nontriglyceride components from Span
rapeseed oil are described. Fractionation ofBrassica campestris var. Span rapeseed oil by molecular distillation yielded 4 triglyceride fractions, all of which contained traces of sterol
esters. An additional triglyceride fraction rich in free and esterified sterols and other volatile components was obtained
from the oil. Separation by adsorption chromatography of Span rapeseed oil yielded three fractions: A) a pure triglyceride
fraction; B) a triglyceride fraction rich in sterol esters; and C) another fraction containing free sterols and other polar
components.
Contribution no. 559 Animal Research Institute. 相似文献
15.
Vesicular lipids from six orange and two tangor varieties were extracted, purified and separated by chromatography into triglycerides,
monogalactosyl diglycerides, steryl esters and esterified steryl glucosides. Methyl esters of the fatty acids found in these
four lipids were prepared and analyzed by gas liquid chromatography. Each of the eight citrus varieties gave a series of four
profiles which could be distinguished from the others. The Temple tangor has four profiles all showing a large percentage
of linolenic acid. In all varieties steryl esters and to a lesser extent esterified steryl glucosides contain relatively large
concentrations of 22∶0 to 26∶0 saturated acids. The profiles differ markedly from the patterns found for these four lipids
in other higher plants studied.
So. Market. Nutr. Res. Div., ARS, USDA. 相似文献
16.
We investigated the effect of three types of plant sterols (4-desmethylsterols, 4,4′-dimethylsterols, and pentacyclic triterpene
alcohols) in three forms (free, esterified with FA, or with phenolic acids) on cholesterol absorption. Plant sterol fractions
derived from soybean (99% 4-desmethylsterols), rice bran (70% 4,4′-dimethylsterols), or shea nut (89% pentacyclic triterpene
alcohols) were fed to male hamsters (n=20/group) as free sterols or esterified with FA or phenolic acids (cinnamic or ferulic). Cholesterol absorption was measured
after 5–8.5 (mean, 7) wk by a dual-isotope technique. Soybean sterol intake significantly reduced cholesterol absorption efficiency
(23%) and plasma total cholesterol (11%). Rice bran sterols tended to lower cholesterol absorption efficiency by 7% and plasma
total cholesterol by 5%, whereas shea nut sterols had no effect. In hamsters, dietary 4-desmethylsterols were more effective
than 4,4′-dimethylsterols in lowering cholesterol absorption and levels of cholesterol in blood. Pentacyclic triterpene alcohols
had no effect on the absorption of cholesterol or on its level in blood. Esterification with FA did not impair the ability
of 4-desmethylsterols and 4,4′-dimethylsterols to inhibit cholesterol absorption, whereas esterification with phenolic acids
reduced this ability. This study supports the use of 4-desmethylsterols, esterified with FA to increase solubility, as the
most effective cholesterol-lowering plant sterols in the diet. 相似文献
17.
Free sterols, steryl esters, and lipid phosphorus were measured in new (current year) needles of Scot's pine during an annual
cycle, and also in one-, two-, and three-year-old needles collected shortly after bud break. Sterols were identified and quantified
by capillary gas chromatography and gas chromatography/mass spectrometry. Steryl esters were hydrolyzed enzymatically. Newly
emerged needles contained highest amounts of free sterols and lipid phosphorus, probably reflecting increased membrane and
organelle production, but low levels of steryl esters. Mature needles contained approximately equal amounts of free and esterified
sterols. The molar phospholipid/free sterol ratio was 3∶1 at all the time periods studied. A dramatic increase of steryl esters
was observed in the one-, two-, and three-year-old needles at times when new needles emerged. The individual free and esterified
sterols were sitosterol, campesterol (presumably together with its C-24 epimer), and cholesterol, at approximately 88, 10,
and 2%, respectively. Isofucosterol, an intermediate in sitosterol biosynthesis, was present almost exclusively in newly emerged
needles. Esterified sterols contained only trace amounts of isofucosterol. Shifts in favor of cholesterol and 24ζ-methyl cholesterol
occurred in the steryl esters during needle differentiation, and saturation grade of esterified fatty acids decreased. In
mature needles, the composition of free sterols and steryl esters remained constant throughout the year. 相似文献
18.
Free and esterified sterols of the common marine dinoflagellateGonyaulax polygramma were identified using capillary gas chromatography—mass spectrometry (GC-MS). Fractions containing free 4α-methyl and 4-desmethyl
sterols were isolated by column chromatography and shown to consist of at least 20 components. Major sterols included 4α,23,24-trimethyl-5α-cholestan-3β-ol
(dinostanol), 4α,23,24-trimethyl-5α-cholest-22E-en-3β-ol (dinosterol), cholest-5-en-3β-ol (cholesterol), 23,24-dimethyl-5α-cholest-22E-en-3β-ol
and 23,24-dimethylcholesta-5,22E-dien-3β-ol. Although the same group of sterols was found in the free and esterified sterol
fractions, the proportions of individual sterols were quite different. The complexity of the sterol distributions, together
with the predominance of dinostanol, distinguishes the sterol composition of this alga from those of other members of theGonyaulacaceae. 相似文献
19.
About 60% of the total sterols in the cotton bud appeared in the free state; the esterified sterol glycosides contained about
50% saturated fatty acids, largely palmitic acid; the principal unsaturated fatty acid was linolenic acid. β-Sitosterol was
the major sterol in all classes of sterol derivatives. The sugar moiety of the esterified sterol glycosides and the sterol
glycoside was galactose. Efforts are continuing to evaluate the minor sterols of cotton buds, some of which appear to be hydroxylated
ecdysones, and to study their relationship to the development of the Boll weevil,Anthonomus grandis Boheman. 相似文献
20.
Minimal deviation hepatoma 7288C cells were cultured in a modified Swim's medium supplemented with decreasing levels of serum,
lipid-free serum, lipid-free serum plus fatty acids, and other additives. Cellular and media neutral lipid classes were quantitated,
the fatty acids of triglycerides and sterol esters analyzed, and the carbon number distribution of triglycerides determined.
Cellular triglyceride biosynthesis virtually was inhibited when the medium was supplemented with bovine serum alone. This
inhibition was not observed when the medium was supplemented with fetal calf serum alone or mixtures of fetal calf serum and
bovine serum. Cells cultivated on medium supplemented with lipid-free serum plus palmitic or linoleic acids had much lower
levels of free and esterified cholesterol. The fatty acid composition of cellular triglycerides and cholesterol esters differed
dramatically from the corresponding media lipid classes. Except when linoleic acid was added to the medium, changes in the
media serum and lipid levels had only marginal effects upon the fatty acid composition of cellular triglycerides and cholesterol
esters. These data, in conjunction with earlier data that showed the media neutral lipid levels did not decrease during cell
growth, indicate that these hepatoma cells utilize little or no serum triglycerides and cholesterol esters. Linoleic acid
added to the medium dramatically reduced the level of 18∶1 acids in cellular triglycerides and cholesterol esters. Palmitic
acid added to the medium did not change the fatty acid compositions significantly. Comparison of experimentally determined
and calculated triglyceride carbon number percentages indicated a random distribution of fatty acids in this glyceride. The
fatty acid composition of cellular triglycerides was similar to the composition of the cholesterol esters. The lack of characteristic
and distinguishable compositions of these two classes that occur in most normal tissues suggests a loss of specificity in
the lipid metabolism of this neoplasm at the class level. 相似文献