Antihypoxic effect of vitamin E and its derivative in rats under modeling of hypoxic conditions of different origin

The increase of ubiquinone content in myocardial mitochondria and succinateubiquinone reductase activity in rat blood leucocytes under hypoxic hypoxia and acute microfocal myocardial damage [table: see text] have been shown. At the same time the succinateubiquinone reductase activity of rat myocardial mitochondria do not change substantially. We simultaneously observe the dramatic drop in NADH-ubiquinone reductase activity under experimental myocarditis. This fact demonstrates higher stability of succinateubiquinone reductase system and differences in metabolical processes under hypoxic conditions of different origin. All vitamin E derivatives studied demonstrate substantial antihypoxic activity, which is connected with increased animals' survivability, ubiquinone content in myocardial mitochondria and stabilization and leveling of succinateubiquinone reducatse activity in rat blood leucocytes. alpha-Tocopherolacetate with shortened to six carbon atoms side chain is the most effective in this respect. We discuss possible mechanisms for the realization of vitamin E and its active derivative's antihypoxic effect.     

Vitamin E, ubiquinone and ubiquinone-dependent enzymes in experimental myocarditis

It is shown that a day after introduction of adrenaline which evokes experimental focal myocarditis the level of ubiquinone and vitamin E content in the myocardial mitochondria increases by 56.8 and 122%, respectively. Succinate-ubiquinone-reductase activity in mitochondria remains practically unchanged, while NADH-ubiquinone-reductase activity considerably falls. 5 days after the focal myocarditis reproduction the content of ubiquinone and NADH-ubiquinone-reductase activity of mitochondria return to the norm, while the vitamin E amount remains higher than in intact animals. 24h after adrenaline introduction the level of succinate-ubiquinone-reductase activity of blood leucocytes considerably grows. It is not normalized even on the 5th day after adrenaline administration. It is supposed that the level of this activity may be an index showing development of the focal myocarditis.     

E-vitamin activity of vitamin E derivatives with experimental encephalomalacia in chicks

When adding pharmacopoeian alpha-tocopherylacetate, short-chain alpha-tocopherylacetate, alpha-tocopherylquinine, short-chain alpha-tocopherylquinone and alpha-tocopheronolactone to E-avitaminotic rations pharmacopoeian alpha-tocopherylacetate and alpha-tocopheronolactone manifest the highest E-vitamin activity in preventing encephalomalacia in chickens. The action of alpha-tocopheronolactone is not directly associated with changes in the content of vitamin E and ubiquinone in the brain and liver tissues. All the studied derivatives are effective in increasing resistance of erythrocytes to osmotic hemolysis. The data obtained evidence for a nonspecific function of vitamin E in preventing alimentary encephalomalacia in chickens as well as for the absence of disturbances in ubiquinone metabolism under conditions of the E-hypovitaminosis experimental model.     

Effect of exercise training on tissue vitamin E and ubiquinone content

Endurance exercise training led to an adaptive increase in the ubiquinone content and cytochrome c reductase activity of red quadriceps and soleus muscles and adipose tissues, but not of cardiac or white quadriceps muscle. These findings are consistent with the well-known positive adaptation of skeletal muscle mitochondria to endurance training. However, there was no concomitant increase in the vitamin E content of tissues, which showed an increase in mitochondrial content. Since ubiquinone is located in the mitochondrial inner membrane and the major pool of vitamin E is also associated with mitochondrial membranes, the results suggest that training causes a substantial decrease in vitamin E concentration in the proliferating muscle mitochondrial membranes, thus depleting muscle mitochondria of their major lipid antioxidant. Since vitamin E is the major cellular, lipid-soluble, chain-breaking antioxidant, these findings indicate increased free radical reactions in the tissues of exercising animals.     

Effects of alpha-tocopherol derivatives on natural quinone levels in the tissues of vitamin E deficient rats]

The effects of alpha-tocopherol and its derivatives (alpha-tocopherylquinone, its short-chained analog--alpha-tocopheronolactone--and short-chained alpha-tocopherylacetate) on the levels of ubiquinone, its cyclic isomer--ubichromenol--and vitamin E in the liver and heart of vitamin E-deficient rats were studied. After injection of alpha-tocopherol derivatives the levels of ubichromenol and ubiquinone in rat liver and heart were increased, while their ratio was decreased. alpha-Tocopheronolactone was found to exert the strongest action, which is probably due to its direct effect on ubiquinone metabolism in rat tissues.     

Vitamin E increases natural cytotoxic activity in seabream (Sparus aurata L.).

The natural cytotoxic activity of head-kidney leucocytes from gilthead seabream (Sparus aurata L.), after in vitro and in vivo vitamin E treatment, against tumor cells was studied by flow cytometry. Leucocytes were incubated in culture medium with different vitamin E supplementations (0.01-10 microg ml(-1)) for 6, 24 or 48 h and the results demonstrate that all the assayed vitamin E supplementations significantly enhanced the natural cytotoxic activity of leucocytes. To determine the effect of a high dietary level of vitamin E on this activity, fish were fed with 0 (control), 600, 1200 or 1800 mg of vitamin E supplementation kg(-1) diet for 2, 4 or 6 weeks. After 2 and 4 weeks of treatment, the natural cytotoxic activity was significantly enhanced at the highest (1.8 g kg(-1) diet) and lowest (600 mg kg(-1) diet) vitamin E supplement dosage, respectively. No effect of the vitamin E supplemented diet on seabream leucocyte natural cytotoxic cell activity was observed after 6 weeks of treatment.     

Activity of antioxidants in serum of animals with experimental crush syndrome]

Ischemia of soft tissues in crush syndrome results in activation of free radical oxidation processes, which negatively effect the functions of many biological systems. The presence of antioxidant system in the body can inhibit the action of free radicals. Antiradical effect of this system is seen in vitamin K, ubiquinone and ascorbic acid. The results of the experiment showed that the quantity of vitamin K, ubiquinone and ascorbic acid increases in the serum of blood after decompression of soft tissues in 14 hours, three and seven days. This fact supports an active participation of antioxidant system in the pathogenesis of crush syndrome.     

Effect of vitamin E on the oxidative state of glutathione in plasma

Reduced and oxidized glutathione levels in red blood cells and plasma from humans were determined after oral vitamin E treatment. The experiments confirmed that vitamin E enhances reduced glutathione levels in red blood cells. Moreover, vitamin E supplement resulted in a significant reduction of the plasma oxidized glutathione content. Thus, it seems that the effect of vitamin E on the reduced glutathione content is not exerted via direct modulation of the glutathione-synthesizing enzymes, but rather by a more general mechanism of preserving reduced glutathione consumption by reducing the burden of the glutathione system.     

Dietary vitamin E and rainbow trout (Oncorhynchus mykiss) phagocyte functions: effect on gut and on head kidney leucocytes

The effects of vitamin E (deficiency or supplementation) on the non-specific immune system in rainbow trout, Oncorhynchus mykiss, were evaluated. Rainbow trout were fed daily a semi-purified diet supplemented with vitamin E at 0, 28 and 295 mg x kg(-1) of diet. After 80 days of experimental feeding, the phagocytic function (respiratory burst evaluated by the CL response, phagocytosis) from gut leucocytes and head kidney enriched macrophages was measured; head kidney cell pinocytosis and serum lysozyme activity were also analysed. The results showed that some phagocyte functions were influenced by dietary vitamin E. When fish were fed the high dietary dose of vitamin E an enhancement of phagocytosis was found, but only significantly for the leucocytes isolated from the gut of rainbow trout; moreover, an impaired response was also observed in the fish fed no vitamin E for 80 days. However, no significant differences were noticed on the oxidative burst (CL) response of both gut and head kidney cells according to the dietary dose of vitamin E. Pinocytosis evaluated on head kidney cells was not influenced by dietary vitamin E. Fish fed vitamin E at 295 mg x kg(-1) had a lower serum lysozyme activity than those fed with vitamin E at 28 mg x kg(-1) and the fish fed no vitamin E for 80 days had an impaired activity. Thus, the present results demonstrate that altered dietary levels of vitamin E modulates the phagocytic functions of gut leucocytes in rainbow trout; moreover, the vitamin E diet effect seems to be greater on the local intestinal response as compared to systemic (head kidney). Taken together, this study confirms the crucial role of gut phagocytes in mucosal non-lymphoid defences in fish.     

Attenuation of blood parameters in smokers and non-smokers after intake of a complex food additive

This report describes an intervention study with healthy volunteers (20 smokers, 28 non-smokers) taking a food additive mainly containing vitamin C (ascorbic acid), vitamin E (alpha-tocopherol), ubiquinone (Q10), vitamin A and zinkoxide for four weeks in a double blind, randomized and placebo controlled manner. Before and after the intervention blood was withdrawn and general blood parameters were analyzed. In addition, lipid soluble antioxidants were analyzed in blood plasma by HPLC and the water soluble antioxidative properties were tested with the enzymic xanthin/xanthinoxidase-reaction. In summary the results show that the smoker-verum group exhibit a significant down regulation of the leukocyte counts. The test for antioxidants show the following significant differences after intervention: Smokers exhibit an increase of both vitamin E and coenzyme Q10 and an attenuation of their (before intervention) clearly increased water soluble-antioxidative potential, non-smokers showed only an increase of vitamin E and trends of an increase of Q10 and water soluble-antioxidative potential. These results may contribute to the discussion of the intrinsic deficiency brought about by smoking and the possible attenuation of part of these deficiency by increasing the intake of certain vitamins or food additives.     

Content of fat-soluble vitamins in human blood serum during the use of food additives with vitamin E and carotene of plant origin]

Vitamin E, A and carotene levels in blood serum of human that were affected by the definite irradiation doses accepting the admixtures of vitamin E and carotene preparations were estimated. The consuming of vitamin E increases vitamin E and A content in blood serum. While obtaining carotene significant increase of vitamin E and carotene content is observed, but it does not influence to vitamin A content. Simultaneous application of both preparations leads to vitamin E level growth being similar to persons, receiving only vitamin E; in this case the vitamin A and carotene content is increasing more actively and produces as early as in the month the carotene accumulation in blood serum. Along side with this the vitamin A content increases only in 3 month, and vitamin E practically does not change. Among estimated persons 45 years older revealed content of vitamin E increase in 3 month of both application of preparation. Application of vitamin E and carotene preparations have expressive positive change of fat-soluble vitamin status in blood serum.     

The mode of action of lipid-soluble antioxidants in biological membranes: relationship between the effects of ubiquinol and vitamin E as inhibitors of lipid peroxidation in submitochondrial particles.

The effects of ubiquinol and vitamin E on ascorbate- and ADP-Fe3+-induced lipid peroxidation were investigated by measuring oxygen consumption and malondialdehyde formation in beef heart submitochondrial particles. In the native particles, lipid peroxidation showed an initial lag phase, which was prolonged by increasing concentrations of ascorbate. Lipid peroxidation in these particles was almost completely inhibited by conditions leading to a reduction of endogenous ubiquinone, such as the addition of succinate or NADH in the presence of antimycin. Lyophilization of the particles followed by three or four consecutive extractions with pentane resulted in a complete removal of vitamin E and a virtually complete removal of ubiquinone, as revealed by reversed-phase high pressure liquid chromatography. In these particles, lipid peroxidation showed no significant lag phase and was not inhibited by either increasing concentrations of ascorbate or conditions leading to ubiquinone reduction. Treatment of the particles with a pentane solution of vitamin E (alpha-tocopherol) restored the lag phase and its prolongation by increasing ascorbate concentrations. Treatment of the extracted particles with pentane containing ubiquinone-10 resulted in a restoration of the inhibition of lipid peroxidation by succinate or NADH in the presence of antimycin, but not the initial lag phase or its prolongation by increasing concentrations of ascorbate. Malonate and rotenone, which prevent the reduction of ubiquinone by succinate and NADH, respectively, abolished, as expected, the inhibition of the initiation of lipid peroxidation in both native and ubiquinone-10-supplemented particles. Reincorporation of both vitamin E and ubiquinone-10 restored both effects.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of vitamin E in the body

The basic experimental data obtained at the Department of Coenzymes' Biochemistry of the A. V. Palladin Institute of Biochemistry of the Ukr. SSR Academy of Sciences as to the biological role of vitamin E are analyzed. Vitamin E, selenium and methionine are found to induce peculiar changes in the activity of glutathione-peroxidase, metabolism of sulphur-containing amino acids, biosynthesis of adenine nucleotides, proteins and nucleic acids. Participation of alpha-tocopherol and its active derivatives in the control of biosynthesis and intertransformation of ubiquinone and its cyclic isomer, ubichromenol, in the animal organism, is proved, which determines to a considerable extent the biological role of vitamin E in the bioenergy processes. It is substantiated in experiments that the detected wide range of the biological effect of vitamin E is associated with the control of RNA biosynthesis. Under these conditions the effect of vitamin E on the RNA synthesis does not depend on the manifestation of antioxidant properties of its molecule and in this sense it is a specific one. The results obtained are discussed for their significance in explanation of the molecular mechanism of the vitamin E action and in substantiation of the possibility to use the results in practical medicine and animal husbandry.     

Ubiquinone deficiency in an auxotroph of Escherichia coli requiring 4-hydroxybenzoic acid

1. Escherichia coli 156:53D2 synthesized ubiquinone only when the growth medium was supplemented with 4-hydroxybenzoate acid. 2. Little or no vitamin K(2) was formed by the mutant under the growth conditions employed, in contrast with wild-type strains. 3. In the mutant ubiquinone deficiency was correlated with low respiration and with low particulate NADH-oxidase and NADH-cytochrome b(1)-reductase activity. 4. Preincubation of ubiquinone-deficient particles with ubiquinone-30 largely restored the NADH-oxidase and NADH-cytochrome b(1)-reductase activities. 5. Various NADH-dye-linked reductases which may be associated with NADH dehydrogenase were not affected by the absence of ubiquinone. 6. The succinate-oxidase complex was less affected than the particulate NADH oxidase by ubiquinone deficiency. 7. A pathway for electrons in the NADH-oxidase complex of the auxotroph of E. coli is proposed and its relationship to the pathway in the wild-type strain is discussed.     

The biomolecule ubiquinone exerts a variety of biological functions

The chemistry of ubiquinone allows reversible addition of single electrons and protons. This unique property is used in nature for aerobic energy gain, for unilateral proton accumulation, for the generation of reactive oxygen species involved in physiological signaling and a variety of pathophysiological events. Since several years ubiquinone is also considered to play a major role in the control of lipid peroxidation, since this lipophilic biomolecule was recognized to recycle alpha-tocopherol radicals back to the chain-breaking form, vitamin E. Ubiquinone is therefore a biomolecule which has increasingly focused the interest of many research groups due to its alternative pro- and antioxidant activity. We have intensively investigated the role of ubiquinone as prooxidant in mitochondria and will present experimental evidences on conditions required for this function, we will also show that lysosomal ubiquinone has a double function as proton translocator and radical source under certain metabolic conditions. Furthermore, we have addressed the antioxidant role of ubiquinone and found that the efficiency of this activity is widely dependent on the type of biomembrane where ubiquinone exerts its chain-breaking activity.     

Distribution of Coenzyme Q Homologues in Brain

Ubiquinone (coenzyme Q₁₀), in addition to its function as an electron and proton carrier in mitochondrial electron transport coupled to ATP synthesis, acts in its reduced form (ubiquinol) as an antioxidant, inhibiting lipid peroxidation in biological membranes and protecting mitochondrial inner-membrane proteins and DNA against oxidative damage accompanying lipid peroxidation. Tissue ubiquinone levels are subject to regulation by physiological factors that are related to the oxidative activity of the organism: they increase under the influence of oxidative stress, e.g. physical exercise, cold adaptation, thyroid hormone treatment, and decrease during aging. In the present study, coenzyme Q homologues were separated and quantified in the brains of mice, rats, rabbits, and chickens using high-performance liquid chromatography. In addition, the coenzyme Q homologues were measured in cells such as NG-108, PC-12, rat fetal brain cells and human SHSY-5Y and monocytes. In general, Q₁ content was the lowest among the coenzyme homologues quantified in the brain. Q₉ was not detectable in the brains of chickens and rabbits, but was present in the brains of rats and mice. Q₉ was also not detected in human cell lines SHSY-5Y and monocytes. Q₁₀ was detected in the brains of mice, rats, rabbits, and chickens and in cell lines. Since both coenzyme Q and vitamin E are antioxidants, and coenzyme Q recycles vitamins E and C, vitamin E was also quantified in mice brain using HPLC-electrochemical detector (ECD). The quantity of vitamin E was lowest in the substantia nigra compared with the other brain regions. This finding is crucial in elucidating ubiquinone function in bioenergetics; in preventing free radical generation, lipid peroxidation, and apoptosis in the brain; and as a potential compound in treating various neurodegenerative disorders.     

The action of membranotropic compounds with various structures on the parameters of the phase transition of dimyristoylphosphatidylcholine

The effect of substances of different nature on the thermodynamic characteristics of dimyristoylphosphatidylcholine (DMPC) phase transition by the differential scanning microcalorimetry has been studied. The substances disposed in hydrophobic part of membrane--alpha-tocopherol, ubiquinone Q10, ionol and vitamin K3 cause the decrease of enthalpy and cooperativity of phase transition. The substances which have the side hydrocarbon chain (tocopherol and ubiquinone Q10) compared with ones without it (ionol and vitamin K3) and reduced quinones (Q10 and vitamin K3) compared with the oxidized ones have stronger influence on the enthalpy and cooperativity of transition. The inclusion of the local anesthetic dicaine disposed mainly in the zone of polar heads of phospholipids into DMPC membranes decreases the temperature of phase transition considerably and practically does not change the cooperativity. A possibility to use the method of differential scanning microcalorimetry to estimate the localization of membrane tropic substances within lipid bilayer is under discussion.     

Blood antioxidant status and urinary levels of catecholamine metabolites in beta-thalassemia.

It has been reported that iron overload in beta-thalassemia leads to an enhanced generation of reactive oxygen species and to oxidative stress. We have studied the oxidant/antioxidant imbalance in the blood of 48 transfusion-dependent beta-thalassemic patients (TLP) (17 males, 31 females, 11-22 year), under chelation therapy, and in 40 sex and age matched healthy controls (CTR). Plasma and lymphocyte levels of vitamin E (Vit E), ubiquinol (CoQ10H2), ubiquinone (CoQ10), plasma concentrations of vitamin A (Vit A), beta-carotene, lycopene, vitamin C (Vit C), total thiols, fatty acid patterns of phospholipids (PL-FA), and plasma and urinary markers of lipoperoxidation (TBA-RM, conjugated dienes, and azelaic acid (AZA), as well as the urinary levels of catecholamine and serotonin metabolites, were evaluated by gas chromatography-mass spectrometry (GC-MS), HPLC and spectrophotometry. Routine laboratory blood analyses were performed on the same samples; 39/48 TLP were HCV positive. Blood samples were collected just before transfusion, the 24 h urine samples the day before. Our results clearly showed that a severe oxidative stress occurs in the plasma of TLP in comparison with CTR. In fact, the levels of lipophilic antioxidants and ascorbate were severely depleted: CoQ10H2 (-62.5%), total CoQ10 (-35.1%), Vit E (-43.8%), beta-carotene (-31.1%), lycopene (-63.7%), Vit A (-35.9%), Vit C (-23.1%). The impairment of the antioxidant status was associated with elevated plasma levels of by-products of lipoperoxidation and urinary concentrations of catecholamine metabolites and of AZA, indicating a high degree of both neurological stress and lipoperoxidation. A significant positive correlation was found between vitamin E and non-transferrin-bound iron (NTBI) (r = -0.81; p < 0.001), while no correlation was found between antioxidant depletion and ferritin serum levels, average blood consumption, or the presence of clinical complications. The administration of selective antioxidants along with an appropriate diet might represent a promising way of counteracting oxidative damage and its deleterious effects on the progression of the disease.     

Non-antioxidative mechanism of cytochrome P-450 stabilization by alpha-tocopherol: the effectiveness in avitaminosis E

The efficiency of alpha-tocopherol as a 7-etoxycumarine deethylase protector in rat liver microsomes damaged by phospholipase A2 at various levels of vitamin E was studied. No selective damage of cytochrome P-450 isoforms possessing a catalytic activity towards 7-etoxycumarine under vitamin E deficiency was observed. Phospholipase A2 decreased the deethylase activity of cytochrome P-450, the efficiency of the damaging action being dependent on vitamin E content in the liver. Exogenous alpha-tocopherol exerts an antiphospholipase effect and protects 7-etoxycumarine deethylase; the protective action is inversely proportional to vitamin E level in the liver. Under normal conditions the damaging effect of phospholipase A2 on cytochrome P-450 is mainly provided for by lysophospholipids, while under vitamin E deficiency both lysophospholipids and free fatty acids exert a damaging action. A possible mechanism of the stabilizing effect of alpha-tocopherol may consist in the interaction of the chromanol nucleus in the vitamin E molecyule both with lysophospholipids and with free fatty acids.     

Vitamin A and isoprenoid synthesis in the rat

1. Vitamin A-deficient rats were compared with similar animals given small amounts of vitamin A sufficient for adequate growth and with animals given large amounts of vitamin A. The effects of pair-feeding and feeding ad libitum were compared. 2. Ubiquinone and cholesterol concentrations in liver were measured at various stages of the deficiency, and the uptake of radioactive mevalonate and acetate into isoprenoid compounds was studied. 3. Ubiquinone concentrations in liver increased markedly in deficient rats compared with adequate controls, and heavy vitamin A supplementation had a further effect in depressing ubiquinone concentrations. These effects were unrelated to food intake or to the size of the organs. 4. Radioactive uptake into ubiquinone was often greater in deficient livers, especially during the early stages of the experiments, but the effect was not consistent. 5. Cholesterol concentrations were usually higher in deficient livers and these were more affected by the feeding regimen. 6. No consistent effect of vitamin A deficiency or of vitamin A dosage on the incorporation of mevalonate into cholesterol or squalene was found. 7. No evidence has been found for a specific effect of vitamin A on isoprenoid synthesis at the metabolic level.