Accumulation of cardiac fatty acids in rats fed synthesized oils containing C 22 fatty acids

Morphological effects of rapeseed oil in rats. I. Short-term studies

Light microscopy of paraffin embedded and frozen sections, supplemented with electron microscopy, was performed on the heart muscle of young rats fed rapeseed oil in short-term experiments. It was confirmed that high levels of rapeseed oil, which contains erucic acid, produce severe lipoidosis of the heart muscle fibres within 10 days. An attempt was made to find out the lowest level of erucic acid in the rat diet to give rise to pathological fatty accumulation. Several frozen sections from each heart or serial sections in combination with electron microscopy were used for this evaluation. The level found to give rise to pathological fatty accumulation was about 2% by weight (w/w), while rats fed 1% erucic acid showed normal myocardium. No direct proof that erucic acid is of importance in human pathophysiology has hitherto been presented. It is concluded, however, that the similarity in reaction among the many species of experimental animals tested by different workers, as well as the basic metabolic disturbances demonstrated, are in strong favour of a similar effect in man.

Physiopathological effects of rapeseed oil: a review

Rapeseed oil has a growth retarding effect in animals. Some investigators claim that the high content of erucic acid in rapeseed oil alone causes this effect, while others consider the low ratio saturated/monounsaturated fatty acids in rapeseed oil to be a contributory factor. Normally erucic acid is not found or occurs in traces in body fat, but when the diet contains rapeseed oil erucic acid is found in depot fat, organ fat and milk fat. Erucic acid is metabolized in vivo to oleic acid. The effects of rapeseed oil on reproduction and adrenals, testes, ovaries, liver, spleen, kidneys, blood, heart and skeletal muscles have been investigated. Fatty infiltration in the heart muscle cells has been observed in the species investigated. In long-term experiments in rats erucic acid produces fibrosis of the myocardium. Erucic acid lowers the respiratory capacity of the heart mitochondria. The reduction of respiratory capacity is roughly proportional to the content of erucic acid in the diet, and diminishes on continued administration of erucic acid. The lifespan of rats is the same on corn oil, soybean oil, coconut oil, whale oil and rapeseed oil diet. Rats fed a diet with erucic acid or other docosenoic acids showed a lowered tolerance to cold stress (+4 degrees C). In Sweden erucic acid constituted 3-4% of the average intake of calories up to 1970 compared with about 0.4% at present.

Morphological effects of rapeseed oil in rats. II. Long-term studies

In long-term studies covering up to 160 days young Sprague-Dawley rats were fed diets containing 40 cal% of fat. The fat component consisted of either conventional rapeseed oil, or Canadian rapeseed oil low in erucic acid, or arachis oil. Myocardial fatty accumulation was demonstrated in light microscopic studies throughout the experiments in rats fed conventional rapeseed oil, but the number of fat droplets decreased with time. The controls fed arachis oil showed no fatty accumulation. In the rats fed conventional rapeseed oil focal myocardial lesions appeared after 40 days on the diet. These consisted of histiocytic infiltration, occurrence of macrophages, myolysis, proliferation of fibroblasts and finally scarring. Such foci were found widely spread in the myocardium of these rats. In the experimental groups given Canadian rapeseed oil from the cultivar Oro no histiocytic foci or scarring were observed. Small myocardial lesions were occasionally found in the control rats. These latter findings were observed on serial sections. It was concluded that this type of lesion is a "normal" finding. The number and size of the foci observed in animals fed conventional rapeseed oil (10% and 2% (w/w) erucic acid in the diet) indicate, however, that they have to be considered pathological under such circumstances. The pathogenesis of the myocardial alteration is discussed and it is concluded that the long-chain fatty acids are responsible. No direct proof has been presented that the described events are of importance in human pathophysiology, However, several circumstances pointing in this direction are discussed. It is concluded that on the basis of our present knowledge a pathological effect of erucic acid and its homologues in man cannot be excluded.

Quality of cold-pressed edible rapeseed oil in Germany

Forty-eight cold-pressed edible rapeseed oils obtained from small- and medium-sized decentralized plants located all over Germany were characterized by different chemical parameters for their composition and by descriptive sensory evaluation. Between the different oils great differences could be noticed for each parameter. The results evidenced that additionally to the features given in the Guidelines for edible fats and oils of the German Food Codex, especially the sensory evaluation, the oxidation stability (Rancimat), content and the composition of tocopherols, the content of trans-fatty acids and the content of steradienes were crucial parameters to guarantee a high-quality product for the consumer.

Lipids and cardiac arrhythmia

In any discussion of lipids and heart disease it is beneficial from the outset to recognise that at least three different pathological processes may be involved. The first of these is atherosclerosis which involves the deposition of "fat" in the coronary vessels, another is thrombogenesis which describes the formation of blood clots in the coronary vessels, and the third is arrhythmia which refers to disorders in the beating of the heart which may become sufficiently serious to cause sudden cardiac death (SCD). Also it is this disturbance in the rhythmic beating of the heart which is responsible for much of the mortality from 'heart attacks' which occur 'outside-of-hospital' in societies like U.S.A., U.K. and Australia. It is this latter condition of cardiac arrhythmia which is the major concern of this review. Because it is often difficult to differentiate the role of lipids in 'heart disease' in man, it has frequently been assumed that all dietary fatty acids have similar effects on the different processes involved, and many unwarranted generalisations have been made which have led to conflicts of opinion amongst physicians and confusion in the lay public. From the animal studies discussed in this review, it is apparent that dietary fatty acids have an important role to play in determining the vulnerability of the myocardium to develop serious ventricular fibrillation (VF) and potentially lethal cardiac arrhythmia. In general, diets rich in saturated fatty acids promote a state of myocardial vulnerability, whilst diets rich in PUFA significantly diminish the probability of developing lethal disorders in cardiac rhythm when the heart is placed under pharmacological (or emotional) stress, or deprived of sufficient blood flow and supply of oxygen. Very recent experiments with the monounsaturated fatty acid (MUFA) oleic acid clearly demonstrate that, at least in rats subjected to ligation of their coronary artery, this acid is not 'neutral' as has been suggested by some for its role in atherosclerosis, but in fact is indistinguishable from saturated fatty acids in its effect in promoting arrhythmia during either regional ischaemia or reperfusion arrhythmia in this animal model of SCD.(ABSTRACT TRUNCATED AT 400 WORDS)

Erucic acid metabolism in rat liver. A combined biochemical and radioautographical study

Metabolism of erucic acid was studied in rat liver in comparison with oleic acid in relation with diet lipids. Rats were fed for 3 or 60 days a balanced diet containing 30% of the calories of either rapeseed oil rich in erucic acid or sunflower seed oil rich in linoleic acid. They were intravenously injected with tritiated erucic or oleic acid. After 1 or 15 min, the radioactivity recovered in liver lipids was 9 to 26% whatever the diet or the acid injected. One minute after injection of erucic acid a high part of radioactivity was recovered in the free fatty acid fraction and as untransformed erucic acid. After 15 min the major part of radioactivity was recovered in the triacylglycerol fraction which contained a high proportion of labelled oleic acid formed by shortening of erucic acid. The autoradiography did not show any marked difference between the labelling of peroxisomes and mitochondria when tritiated erucic or oleic acid was injected. These data do not bring about arguments for a peroxisomal nor for a mitochondrial location of erucic acid shortening in liver.

Relationship between dietary fatty acid, selenium, and degenerative cardiomyopathy

With the finding of an increasing number of cases of degenerative cardiomyopathy (DCM) amongst patients in Chongqing, Sichuan, People's Republic of China, an attempt has been made to delineate possible etiological factors. In this province endemic for Keshan disease and with considerable consumption of oils high in erucic acid, the latter does not appear to be an operative noxious agent in DCM. Additionally, it does not appear to be caused by excessive oxygen radicals, low levels of antioxidants or low selenium levels. However, lower omega-3 fatty acid levels along with higher serum lipids may be the mechanism, via higher thromboxane levels, of the production of the myocardial degeneration seen in DCM.

Effects of dietary saturated fat on erucic acid induced myocardial lipidosis in rats

Male Sprague-Dawley rats were fed for one week diets containing 20% by weight fat/oil mixtures with different levels of erucic acid (22:1n-9) (approximately 2.5 or 9%) and total saturated fatty acids (approximately 8 or 35%). Corn oil and high erucic acid rapeseed (HEAR) oil were fed as controls. The same hearts were evaluated histologically using oil red O staining and chemically for cardiac triacylglycerol (TAG) and 22:1n-9 content in cardiac TAG to compare the three methods for assessing lipid accumulation in rat hearts. Rats fed corn oil showed trace myocardial lipidosis by staining, and a cardiac TAG content of 3.6 mg/g wet weight in the absence of dietary 22:1n-9. An increase in dietary 22:1n-9 resulted in significantly increased myocardial lipidosis as assessed histologically and by an accumulation of 22:1n-9 in heart lipids; there was no increase in cardiac TAG except when HEAR oil was fed. An increase in saturated fatty acids showed no changes in myocardial lipid content assessed histologically, the content of cardiac TAG or the 22:1n-9 content of TAG at either 2.5 or 9% dietary 22:1n-9. The histological staining method was more significantly correlated to 22:1n-9 in cardiac TAG (r = 0.49; P less than 0.001) than to total cardiac TAG (r = 0.40; P less than 0.05). The 22:1n-9 content was highest in cardiac TAG and free fatty acids. Among the cardiac phospholipids, the highest incorporation was observed into phosphatidylserine, followed by sphingomyelin. With the addition of saturated fat, the fatty acid composition showed decreased accumulation of 22:1n-9 and increased levels of arachidonic and docosahexaenoic acids in most cardiac phospholipids, despite decreased dietary concentrations of their precursor fatty acids, linoleic and linolenic acids.

Erucic acid metabolism in rat heart. A combined biochemical and radioautographical study

Metabolism of Erucic Acid was studied in rat heart in comparison with that of oleic acid, particularly in relation with diet lipids. Rats were fed for 3 or 60 days a diet containing 30% of the calories of either Rapessed Oil, rich in erucic acid or sunflower seed oil rich in linoleic acid. They were I.V. injected with tritiated erucic or oleic acid. After 1 or 15 min the radioactivity recovered in heart lipids was very low whatever the diet (1 to 2%). One minute after injection of erucic acid the radioactivity was mainly recovered in the free fatty acid fraction and as untransformed erucic acid. After 15 min the major part of radioactivity was recovered in the triacylglycerol fraction which contained a high proportion of labelled oleic acid formed by shortening of erucic acid. When oleic was injected, the radioactivity was principally recovered in triacylglycerols as untransformed oleic acid whatever the experimental conditions. Electron microscopy showed that a much higher proportion of peroxisomes, was present in heart cells, following sunflower seed oil diet as compared to rapeseed oil diet. In all cases mitochondria supported the greater part of radioactivity, especially when erucic acid was injected in rats fed rapeseed oil. After sunflower seed oil, a noticeable radioactivity was observed in peroxisomes, most of them containing silver grains, especially when oleic acid was injected. According to the data reported, peroxisomes do not seem more implicated than mitochondria in the metabolism of erucic acid in myocardium.

The composition of cardiac phospholipids in rats fed different lipid supplements

Changes in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrhythmia and ischemia, we have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower-seed oil or sheep fat. Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine, phosphatidylethanolamine or diphosphatidylglycerol,--the phospholipid classes that together account for more than 90% of the total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical. However, in general, feeding a linoleic acid-rich sunflower seed oil supplement resulted in an increase in the omega-6 family of fatty acids, whereas feeding the relatively linoleic acid-poor sheep fat supplement decreased the level of omega-6 fatty acids but increased the levels of the omega-3 family, resulting in major shifts in the proportions of these families of acids. In particular, the ratio of arachidonic acid: docosahexaenoic acid (20:4,omega-6/22:6,omega-3), which is higher in all phospholipids of atria than ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in the fatty acid composition of atrial and ventricular phospholipids of rat heart following standard and lipid-supplemented diets

1. The major saturated fatty acids of the phospholipids of rat heart atria and ventricles are similar and are not greatly altered by supplementing the diet with widely different types of lipid. 2. There are important differences in the relative proportions of the major unsaturated fatty acids of the phospholipids of these anatomically and functionally distinct regions of the heart. 3. The proportions of linoleic (C18:2, eta-6) and docosahexaenoic (C22:6, eta-3) acid are significantly higher in the ventricles than in the atria; the proportions of oleic (C18:1, eta-9) arachidonic (C20:4, eta-6) and docosatetraenoic acids (22:4, eta-6) are higher in atria. 4. The differences in unsaturated fatty acid profiles persist even after twelve months of feeding lipid supplements of sunflower seed oil (SSO) or sheep kidney (perirenal) fat (SKF). 5. However, the ratios of arachidonic to docosahexaenoic acid in both tissues are changed by decreasing the intake of linoleic acid, which apparently favours the conversion of dietary linolenic (C18:3, eta-3) to docosahexaenoic acid. The level of docosahexaenoic acid is greater in the ventricles than in the atria, and greatest when the animals were fed SKF diet. 6. The physiological and pharmacological differences in ventricles and atria may arise from differences as fundamental as the phospholipid fatty acid composition of cardiac membranes.

Effect of strain, sex and duration of feeding on plasma fatty acids of rats fed various dietary oils

Experiments were conducted to determine if regression of cardiac lipidosis and strain or sex differences in susceptibility to cardiopathological change induced by rapeseed oils are coincident with physiological differences in fatty acid substrates supplied to the heart. Plasma fatty acid composition was determined in male Sprague-Dawley rats after 7 or 28 days and in female Sprague-Dawley and male Chester-Beatty rats after 28 days of feeding high or low erucic acid rapeseed oils, soybean oil or peanut oil. After 28 days, C14:0 and C18:1 fell and C20:4 increased as a percent of total fatty acid in all animals irrespective of oil fed, suggesting that changes in plasma fatty acids normally occur with development. Saturated and essential fatty acid profiles of male and female rats were different. Differences in plasma fatty acids stemming from sex-related physiological differences in whole body fat metabolism may form the basis of lower cardiopathological involvement for females. Results suggest physiological differences unrelated to plasma fatty acids determine strain differences in timing and severity of rapeseed oil-induced cardiac pathology.

beta-Oxidation of the coenzyme A esters of vaccenic, elaidic, and petroselaidic acids by rat heart mitochondria

Rates of beta-oxidation of the coenzyme A esters of vaccenic, elaidic, and petroselaidic acids as well as their respective cis isomers by rat heart mitochondria were measured and compared. At all concentrations studied, vaccenoyl-CoA was oxidized more rapidly than elaidoyl-CoA, but more slowly than oleoyl-CoA except at high substrate concentrations. All trans octadecenoyl-CoA esters were oxidized at a slower rate than their respective cis or saturated isomers. Oxidation rates decreased as the double bond approached the carboxyl-end.

Comparison of lipid status in the hearts of piglets and rats on short term feeding of marine oils and rapeseed oils

A series of 4 experiments with piglets and one experiment with rats has been conducted to establish the cardiac lipid status of weanling (3 weeks old) male animals fed fats with different contents of docosenoic fatty acids. Experimental fats were rapeseed oil (RSO) (48.0% 22:1), refined fish oil (RFO) (14.6% 22:1), partially hydrogenated fish oil (PHFO) (14.3% 22:1) and lard (0% 22:1) combined with sunflower seed oil (SFO) in different proportions in diets with 21% total fat. Lipidosis could not be detected in piglets as increased heart weights, by chemical assay for myocardial contents of triglycerides, or by accumulation of docosenoic fatty acids or nonesterified fatty acids (NEFA). In rats, diets with RSO at a level of 16% increased myocardial triglyceride and docosenoic fatty acid contents about 7 times while the effect on cardiac NEFA was inconsistent. Histological examinations of the hearts revealed stainable intracellular fat droplets in some piglets fed 16% RSO for 8 to 13 days, but not after 2, 4 and 6 and 16, 19 and 22 days of feeding. After 10 days of feeding, mild to moderate histological lipidosis was found in piglets fed diets containing 2% or more of 22:1 fatty acids, with no significant difference between RSO, RFO and PHFO in this respect. The same diets in rats gave about 5 times more histological lipidosis than in piglets. This is attributed to a difference in species response, the rat reacting in a more pronounced manner than the piglet. The cardiac lipidosis no-effect level in piglets corresponded to a daily intake of docosenoic fatty acids of 0.4 g per kg body weight. Mild lipidosis was also found in a few animals on docosenoic acid-free diets.

Effects of cold stress on rats fed different levels of docosenoic acids

Male Sprague-Dawley rats, 4 weeks old, were subjected to an ambient temperature of 4 C for periods up to 24 days and fed a synthetic diet containing one of the following oils: peanut oil (PO), rapeseed oil (RO), low erucic acid rapeseed oil (LO), and partially hydrogenated marine oil (HO), each at 20% w/w. A parallel experiment using the same oils was performed at room temperature (23 C). During cold stress, animals on the RO diet showed higher mortality than all other groups; all 20 animals in this group died within 5 days. At room temperature, however, all animals survived. The lipid accumulation in the heart reached its peak in all groups after 3 days and then gradually declined. The accumulation was most pronounced in the RO animals and coincided with the high mortality at 4 C. The fatty acid composition of the cardiac triglycerides reflected that of the diet, while the composition of the cardiac lecithin was only marginally modified.

Eicosenoic and docosenoic acid incorporation in serum lipoproteins in rats fed rapeseed oil

Rats were fed rapeseed oil rich in eicosenoic (20:1) and docosenoic (22:1) acids for 7 days, and the fatty acid composition of the lipid classes of serum and serum lipoproteins was determined. Concentrations of 20:1 and 22:1 acids in the lipid classes were variable, especially among lipoproteins, and were a direct function of the alimentary state of the animal. The results suggest differences in the incorporation of the above acids among the major lipoprotein types and various lipid classes within a given lipoprotein type. The quick partial disappearance of very low density lipoproteins (VLDL) and of low density lipoproteins (LDL) containing 20:1 and 22:1 acids upon starvation and the preferential incorporation of these acids in the triacylglycerols of high density lipoproteins (HDL) are discussed.

Nutritional effects of partially hydrogenated low erucic rapeseed oils

The incidence of cardiac lesions in male rats fed rapeseed oil (Brassica campestris, cultivar "Span") was lower with partially hydrogenated oil (iodine value 78) than withe the liquid oil which had been treated in various ways. Another rapeseed oil (Brassica napus, cultivar "Tower") was similarly improved when hydrogenated to iodine value 76.6, but not at iodine value 97.1, as demonstrated in both Sprague-Dawley and Wistar rats. The improved nutritional quality of hydrogenated oil appeared not to be related to the decreased concentration of linolenic acid, because that fatty acid in linseed oil with or without erucic acid did not increase the incidence of lesions. A relatively high concentration of docosahexaenoic acid in the cardiac fatty acids was observed in adversely affected groups, but a lower concentration was found with the appropriately hydrogenated rapeseed oil.

Monoethlenic C20 and C22 fatty acids in marine oil and rapeseed oil. Studies on their oxidation and on their relative ability to inhibit palmitate oxidation in heart and liver mitochondria

1. Carnitine esters of erucic acid (22:1 n-9 cis), cetoleic acid (22:1 n-11 cis), brassidic acid (22:1 n-9 trans), gadoleic acid (20:1 n-9 cis) and oleic acid (18:1 n-9 cis) have been compared as mitochondrial substrates and as inhibitors of palmitoylcarnitine oxidation in heart and liver mitochondria. 2. Both the rate of intramitochondrial-CoA acylation and the rate of beta-oxidation decreases as the chain length increases from C18 to C22. There are no significant differences among the three C22 isomers as oxidizable substrates. 3. All the tested acylcarnitines inhibit palmitoylcarnitine oxidation. The C18 and C20 acylcarnitines inhibit by virtue of being competing substrates; i.e. the respiration is not inhibited. The C22-isomers inhibit also respiration; this shows that the inhibition of palmitolycarnitine oxidation is not compensated for by oxidation of C22-acylcarnitines. Brassidoylcarnitine inhibits the oxidation of palmitoylcarnitine and respiration less than erucoyl-and cetoleoylcarnitine. The different behaviour of the C22-isomers is probably due to the difference in their competitive properties with respect to long-chain acyl-CoA dehydrogenase. 4. All C22 acylcarnitines seem to be relatively better oxidized in the liver than in the heart mitochondria while their inhibitory effect on the usage of the radioactive palmitoylcarnitine is very similar. 5. Palmitoylcarnitine inhibits almost completely the "endogenous" formation of acetyl-CoA presumably from malate via pyruvate in the liver mitochondria while the C22-acylcarnitines cause only a partial inhibiton of this acetyl-CaO formation.

The effects of original and randomized rapseed oils containing high or very low levels of erucic acid on cardiac lipids and myocardial lesions in rats

The nutritional status of the very lowerucate, rapseed oil, Brassica napus var. 'Tower,' was compared with that of the high-erucate oil, Brassica napus var. 'Target,' as well as with corn oil. The effect of randomization on the nutritional qualities of rapeseed oil was investigated as well. The feeding of diets containing the original and randomized 'Tower' oil or the original 'Target' oil, at the 20% level by weight, gave growth rates which were not significantly different from that for corn oil. However, the randomized 'Target' oil gave growth rates which were significantly less than all other groups. The growth results could not be explained simply on the basis of food consumption. The level of triglycerides in the hearts of rats fed the very low-erucate oils was not significantly different from the corn oil group. Triglyceride concentrations in the hearts of animals given the high-erucate oils were 7-12 times greater than all other groups. The level of total fatty acids in tissue phospholipids was the same regardless of dietary treatment. Fatty acid compositions of the tissue lipid were the same in animals fed either the original or randomized rapeseed oils. A much higher incidence of focal myocardial necrosis was found in animals receiving high-erucate rapeseed oil relative to animals given the corn oil. The incidence in rats fed diets containing very low-erucate rapeseed oil was intermediate between these latter two extremes.

[Fatty acids in 80 brands of edible vegetable oil and in 14 brands of mayonnaise (author's transl)]

The fatty acid patterns have been defined in 80 commonly used table oils chosen at random and of 14 brands of mayonnaise commercially available in West Germany. In addition, sterols of the various mayonnaises were analysed. The oils could be grouped into 8 different categories: 12 oliver oils, 8 maize oils, 14 soya oils, 5 linseed oils, 22 sunflower oils, 3 safflower oils, 5 groundnut oils, and 8 rapeseed oils. As a result of the analyses, it is in almost every case a question of a pure variety of non-animal oils. The range of the values obtained for the composition of the fatty acids for each variety, which can be considerable, represents a modern complement to previous analyses. The fatty acid pattern of 3 additional commerical table oils suggest an amalgamation with fats of other types, among which are 2 cases of mixture with rapeseed oils. For mayonnaise, soya oil is used almost exclusively as a fat component. The presence of sunflower oil was only confirmed in one brand of mayonnaise. The concentrations of cholesterol which were determined lie between 17.0 and 72.3 mg (average 53 mg) per 100 g mayonnaise, so that even in the case of persons which present an elevated risk of atherosclerosis there can be no objection to the consumption of mayonnaise. The nutritive-physiological significance of these various oils for human nutrition is thoroughly discussed. A possible health hazard is the sale of vegetable oils rich in erucic acid permitted in the West German Republic (proportion of erucic acid in the 8 samples examined: 223-53%). These vegetable oils, as is shown by the additionally indicated trade names with the corresponding supplementary specifications are overwhelmingly labelled as vegetable oil (Pflanzenöl) or table oil (Speiseöl). The purchase prices indicated and paid by us for the oils examined are subject to considerable fluctuations even for oils of the same quality.

Brassica campestris var. Span: II. Cardiopathogenicity of fractions isolated from span rapeseed oil when fed to male rats

Rapeseed oils low in erucic acid caused myocardial lesions when fed to weanling male rats for 16 weeks. The cardiopathogenic properties appear to be associated with the triglycerides of the oil, and not to nontriglyceride components present in fully refined rapeseed oil. Cardiac lipid analysis confirmed that erucic acid accumulation was proportional to the concentration of this acid in the diet.

Brassica compestris var. Span: I. Fractionation of rapeseed oil by molecular distillation and adsorption chromatography

Procedures for the large scale isolation of pure triglycerides and fractions rich in nontriglyceride components from Span rapeseed oil are described. Fractionation of Brassica 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 ffaction; B) a triglyceride fraction rich in sterol esters; and C) another fraction containing free sterols and other polar components.

Studies on the mechanism of the inhibitory effects of erucylcarnitine in rat heart mitochondria

1. The mechanism of the inhibitory effect of erucylcarnitine on palmityl-carnitine oxidation in rat heart mitochondria was studied. 2. Erucylcarnitine inhibited in the same time the oxidation of [U-14-C]-palmitylcarnitine and the total rate of oxygen uptake. Other acylcarnitines competed as well for the oxidation with radioactive palmitylcarnitine, but they were well oxidized themselves, so that the total oxygen uptake did not decrease. 3. The presence of erucylcarnitine did not change the distribution pattern of Krebs cycle intermediates derived from [U-minus 14 C] palmitylcarnitine except that succinate/malate ratio increased. 4. The presence of erucylcarnitine did not lead to the formation of any beta-oxidation cycle intermediates from [U-minus 14 C] palymitylcarnitine. The formation of beta-hydroxy-palmityl derivative when rotenon was included into the incubation medium, decreased in the presence of erucylcarnitine. 5. It is postulated, that the inhibited entrance of palmityl groups into the beta-oxidation cycle is due to the fact that erucylcarnitine and palmitylcarnitine behave as substrate-competitive inhibitors for long chain acyl-CoA dehydrogenase. 6. There was observed a latency of 1-2 min in the effect of erucylcarnitine on the palmitylcarnitine oxidation, which seems to correspond to the time required for the formation of high amounts of intramitochondrial erucyl-CoA. 7. Erucylcarnitine inhibited the total oxygen uptake with long, medium and short chain acylcarnitines, pyruvate and alpha-ketoglutarate as substrates, while the oxidation of succinate was not affected. 8. Sequestration of free CoA in the form of very slowly metabolized erucyl-CoA is proposed as the partial explanation of the observed inhibitory effects of erucylcarnitine on the oxidation of CoA-dependent substrates (alternatively to the inhibition at the level of acyl-CoA dehydrogenases in case of acylcarnitines).