scholarly journals Cholesterol esterification in rabbit plasma

1969 ◽  
Vol 115 (3) ◽  
pp. 555-561 ◽  
Author(s):  
V. Stefanovich

1. When [4−14C]cholesterol, attached to β-globulin or dispersed with Tween 20, was incubated with fresh rabbit (New Zealand albino females) plasma, 30–47% esterification was observed. The optimum pH was 6·8. This esterification was accomplished by the transfer of fatty acids from the C-2 position of lecithin (phosphatidylcholine) to cholesterol. 2. There was no evidence that triglycerides or free fatty acids participated directly in this reaction. Lecithins with labelled palmitic acid, oleic acid and linoleic acid in the 2-position yielded 3·2, 4·8 and 6·8% of cholesteryl esters respectively. This pattern reflects that which is normally observed in the cholesteryl esters of rabbit plasma and supports the concept that plasma cholesteryl esters originate from the plasma. 3. Snake venom (containing phospholipase A), sulphoevernan [an α-(1→3,1→4)-sulphopolyglucan with 12% sulphur], thiol-blocking agents (p-chloromercuribenzoate and N-ethylmaleimide), or an atherogenic diet (stock diet supplemented with 1% cholesterol for 8 weeks) were all effective inhibitors of this cholesterol esterification.

1969 ◽  
Vol 23 (3) ◽  
pp. 709-714 ◽  
Author(s):  
R. C. Noble ◽  
W. Steele ◽  
J. H Moore

1. The fatty acid compositions of the plasma cholesteryl esters, phospholipids, triglycerides and unesterilied fatty acids were determined in two sheep at various times after they had been given intraruminal infusions of emulsions of maize oil or linoleic acid.2. The concentration of linoleic acid in the plasma triglycerides began to increase 3 h after infusion began. The infusions of maize oil and linoleic acid resulted in the appearance of peak concentrations of linoleic acid in the plasma triglycerides 6 and 12h respectively after infusion began.3. After the infusion of maize oil the plasma triglycerides showed an increasein theconcentration of stearic acid but after the infusion of linoleic acid the plasma triglycerides showed an increase in the concentration of oleic acid.4. The concentration of linoleic acid in the plasma phospholipids and cholesteryl esters did not begin to increase until 6–9 h and 24–25 h respectively after the infusions had begun.5. No evidence was found for an absorption mechanism which involved the direct incorporation of linoleic acid into the blood phospholipids or cholesteryl esters.


1969 ◽  
Vol 23 (1) ◽  
pp. 141-152 ◽  
Author(s):  
J. H. Moore ◽  
R. C. Noble ◽  
W. Steele

1. The fatty acid compositions of the plasma cholesteryl esters, phospholipids, triglycerides and unesterified fatty acids were determined in three sheep at various times after they had been given intra-abomasal infusions of emulsions of linseed oil, maize oil or linoleic acid.2. The concentrations of linolenic acid or linoleic acid in the plasma triglycerides began to increase 1.5 h after infusion of the emulsions had begun. As the concentration of linolenic or linoleic acids in the plasma triglycerides increased, the concentrations of palmitic and stearic acids decreased, hut there were no appreciable changes in the concentrations of oleic acid.3. The concentrations of linolenic or linoleic acid in the plasma phospholipids and cholesteryl esters did not begin to increase until 8–9 h and 24–25 h respectively after the infusions of the emulsions had begun.4. It is suggested that, after absorption from the small intestine of the sheep, linolenic and linoleic acids are transported in triglyceride form to the liver where the triglycerides are partially or completely hydrolysed. These C18 polyunsaturated acids are then preferentially utilized for the synthesis of phospholipids and cholesteryl esters but not for the re-synthesis of triglycerides.


1992 ◽  
Vol 285 (2) ◽  
pp. 557-562 ◽  
Author(s):  
T Liang ◽  
S Liao

Human or rat microsomal 5 alpha-reductase activity, as measured by enzymic conversion of testosterone into 5 alpha-dihydrotestosterone or by binding of a competitive inhibitor, [3H]17 beta-NN-diethulcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one ([3H]4-MA) to the reductase, is inhibited by low concentrations (less than 10 microM) of certain polyunsaturated fatty acids. The relative inhibitory potencies of unsaturated fatty acids are, in decreasing order: gamma-linolenic acid greater than cis-4,7,10,13,16,19-docosahexaenoic acid = cis-6,9,12,15-octatetraenoic acid = arachidonic acid = alpha-linolenic acid greater than linoleic acid greater than palmitoleic acid greater than oleic acid greater than myristoleic acid. Other unsaturated fatty acids such as undecylenic acid, erucic acid and nervonic acid, are inactive. The methyl esters and alcohol analogues of these compounds, glycerols, phospholipids, saturated fatty acids, retinoids and carotenes were inactive even at 0.2 mM. The results of the binding assay and the enzymic assay correlated well except for elaidic acid and linolelaidic acid, the trans isomers of oleic acid and linoleic acid respectively, which were much less active than their cis isomers in the binding assay but were as potent in the enzymic assay. gamma-Linolenic acid had no effect on the activities of two other rat liver microsomal enzymes: NADH:menadione reductase and glucuronosyl transferase. gamma-Linolenic acid, the most potent inhibitor tested, decreased the Vmax. and increased Km values of substrates, NADPH and testosterone, and promoted dissociation of [3H]4-MA from the microsomal reductase. gamma-Linolenic acid, but not the corresponding saturated fatty acid (stearic acid), inhibited the 5 alpha-reductase activity, but not the 17 beta-dehydrogenase activity, of human prostate cancer cells in culture. These results suggest that unsaturated fatty acids may play an important role in regulating androgen action in target cells.


Author(s):  
Carrillo W ◽  
Carpio C ◽  
Morales D ◽  
Vilcacundo E ◽  
Álvarez M ◽  
...  

  Objective: The aim of this work was to determine the fatty acids content in corn seeds oil (Zea mays) sample cultivated in Ecuador.Methods: Corn oil was obtained from corn oil seeds using the cold pressing method. Methyl esters fatty acids analysis were carried out using the gas chromatography (GC) method with a mass selective detector and using the database library NIST 14.L to identify the compounds present in the corn seed oil.Results: Methyl esters fatty acids were identified from corn (Z. mays) seeds using the GC mass spectrometer (GC-MS) analytical method. Fatty acids were analyzed as methyl esters on a capillary column DB-WAX 122-7062 with a good separation of palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, arachidic acid, and linolenic acid. The structure of methyl esters fatty acids was determined using the GS-MS method. Corn oil has a high content of linoleic acid (omega 6) with a value of 52.68% of the total content of fatty acids in corn oil and 29.70% of oleic acid (omega 9) of the total content of fatty acids in corn oil. The sample presented a value of 12.57% of palmitic acid.Conclusions: Corn oil shows a good content of fatty acids omega 6 and 9. The higher value was of omega 6 with 52.68% content. Corn oil has a good proportion of polyunsaturated of lipids (53.80%) and 14.86% of saturated lipids.


1986 ◽  
Vol 59 (5) ◽  
pp. 800-808 ◽  
Author(s):  
James M. Sloan ◽  
Michael J. Maghochetti ◽  
Walter X. Zukas

Abstract An effort to characterize the reversion process of guayule rubber when naturally-occurring guayule resin components are present has shown that these components act as a reversion-retarding material. The amount of reversion resistance varies as a function of temperature, concentration, and type of fatty acid. Of the three fatty acids used, linoleic acid, stearic acid, and oleic acid, linoleic acid performed the best for reversion resistance, followed by stearic acid, then oleic acid. When the temperature was increased 10°C, an increase of 15% reversion was observed. This held true for the three temperatures studied. In addition, the amount of reversion improvement upon addition was 20% reversion. In the case of curing at 150°C, this resulted in 0% reversion. The 20% resistance improvment was consistent for the 3 temperatures studied.


2012 ◽  
Vol 7 (10) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Rashmi Kumari ◽  
Gopal Rao Mallavarapu ◽  
Vinod Kumar Jain ◽  
Sushil Kumar

Fatty oils of the seeds of Cleome viscosa accessions from Delhi, Jaipur, Faridabad, Surajkund and Hyderabad were methylated and analyzed by GC and GC-MS. The major fatty acids, identified as their methyl esters, of the oils from these five locations were palmitic acid (10.2-13.4%), stearic acid (7.2-10.2%), oleic acid (16.9-27.1%) and linoleic acid (47.0-61.1%). In addition, palmitoleic acid, octadec-(11 E)-enoicacid, arachidic acid, eicosa-(11 Z)-enoic acid, linolenic acid, heneicosanoic acid, behenic acid, lignoceric acid, pentacosanoic acid, hexacosanoic acid, 12-oxo-stearic acid, and the alkanes tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triocontane, hentriacontane and dotriacontane, were also identified as minor and trace constituents in some of these oils.


1963 ◽  
Vol 18 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Wolfgang Heinen ◽  
Ingeborg V. D. Brand

1. Three fatty acid oxidizing enzymes, stearic and oleic acid oxidase as well as lipoxidase have been shown to be present in leaves of Gasteria verricuosa.2. By following the activity of these enzymes after injury we considered that they are involved in cutin synthesis which takes place at the wounded top of the leaf.3. Comparing the activity near the wounded part and the untreated inner sphere of the leaf lead to the conclusion that two of the oxidases (stearic and oleic oxidase) serve as substrate donors for lipoxydase by converting stearic into oleic and the latter into linoleic acid.4. Since the level of polyenic acids in leaves is high in comparison to saturated fatty acids, the activity of stearic and oleic oxidase only increases in the late phase of cutin synthesis, while lipoxydase is highly activated at the top directly after wounding and in the inner part of the leaf 3 - 4 weeks after cutin synthesis has started. At the same time pectinase shows its highest activity, suggesting that the formation of the pectic layer is secondary to the formation of cutin.5. Simultaneously to the enzymatic assays, cutin formation was followed by macro- and microscopic studies.6. The mode of action of lipoxydase and the interrelationship of the oxidizing enzymes in the formation of cutin are discussed and a formula for the structure of Gasteria cutin is given.7. According to the data presented here and the results obtained from literature, a possible scheme for cutin synthesis is given.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Liying Fan ◽  
Jun Ren ◽  
Yuting Yang ◽  
Limin Zhang

The essential nutrients of 23 wild hazelnuts (Corylus heterophylla) grown in northeast China were analyzed in order to sieve good species and study the factors effected on nut quality. Hazelnut kernels contained 45.76–62.78% fat similar to Corylus avellana and main fatty acids were oleic acid (79.75%), linoleic acid (15.42%), palmitic acid (3.29%), and polyunsaturated fatty acids ranged between 10.37% and 25.88%. Average protein, soluble sugar, starch, and ash contents of hazelnut kernels were 25.12%, 4.98%, 2.03%, and 3.04%, respectively. The amount of amino acids, mostly as glutamic acid, arginine, and aspartic acid, was also determined by the hazelnut varieties. The abovementioned variation was explained by growing environmental differences. Among them, the 11th sample was highest in protein content (30.21%) and 18th sample highest in fat content, while the 5th and 14th samples had relatively balanced nutrients. So, when planning to select new cultivars, we primarily considered different hazelnut qualities.


Author(s):  
Vilcacundo E ◽  
Alvarez M ◽  
Silva M ◽  
Carpio C ◽  
Morales D ◽  
...  

 Objective: The aim of this study was to determine the fatty acids composition in a tocte seeds oil (Juglans neotropica Diels) sample cultivated in Ecuador.Methods: Tocte oil was obtained from tocte seeds using the cold pressing method. Fatty acids analysis was carried out using the gas chromatography method with a mass selective detector (GC/MSD) and using the database Library NIST14.L to identify the compounds.Results: Methyl esters fatty acids were identified from tocte (J. neotropica Diels) walnut using the GC–MS analytical method. The total lipid content of tocte walnuts seeds of plants cultivated in Ecuador was of 49.01% of the total lipid content on fresh weight. Fatty acids were analyzed as methyl esters on a capillary column DB-WAX 122-7062 with a good separation of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. The structure of methyl esters fatty acids was determined using the GC–MS. Tocte walnut presents 5.05% of palmitic acid, 2.26% of stearic acid, 19.50% of oleic acid, 65.81% of linoleic acid, and 2.79% linolenic acid of the total content of fatty acids in tocte oil. Fatty acids content reported in this study were similar to the data reported for other walnuts seeds.Conclusions: Tocte seeds are a good source of monounsaturated and polyunsaturated fatty acids. Tocte oil content oleic acid and with a good content of ɷ6 α-linoleic and ɷ3 α-linolenic. Tocte walnut can help reduce risk cardiovascular diseases in Ecuador for their good composition of fatty acids.


2003 ◽  
Vol 375 (2) ◽  
pp. 275-285 ◽  
Author(s):  
S. Duy NGUYEN ◽  
Dai-Eun SOK

The effect of lipids on PON1 (paraoxonase 1), one of antioxidant proteins in high-density lipoprotein, was investigated in respect to inhibition, protection against oxidative inactivation, and stabilization. When the effect of lipids on the PON1 activity was examined, a remarkable inhibition was expressed by polyenoic fatty acids (C18:2–C20:5). Linoleic acid, the most potent (Ki, 3.8 μM), showed competitive inhibition. Next, various lipids were examined for prevention against the inactivation of PON1 by ascorbate/Cu2+, which caused a remarkable (≥90%) inactivation of PON1. Compared with saturated fatty acids (C6–C18), exhibiting a modest protection (9–40%), monoenoic acids (C16:1–C20:1) showed a greater maximal protective effect (Emax, 70–82%), with oleic acid being the most effective (EC50, 2.7 μM). In contrast, polyenoic acids showed no protection. Noteworthy, linoleic acid prohibited the protective action of oleic acid non-competitively. In the structure–activity relationship, a negatively charged group seems to be required for the protective action. Consistent with this, dioleoylphosphatidylglycerol, negatively charged, was more protective than dioleoylphosphatidylcholine. These data, together with requirement of Ca2+ (EC50, 0.6 μM) for the protective action, may support the existence of a specific site responsible for the protective action. A similar protective action of lipids was also observed in the inactivation of PON1 by ascorbate/Fe2+, peroxides or p-hydroxymercuribenzoate. Separately, PON1 was stabilized by oleic acid or oleoylated phospholipids, in combination with Ca2+, but not linoleic acid. These results suggest that in contrast to an adverse action of linoleic acid, monoenoic acids or their phospholipid derivatives play a beneficial role in protecting PON1 from oxidative inactivation as well as in stabilizing PON1.


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