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Neuroscience Letters Jan 2015The effects of the vitamin E isomer δ-tocopherol on neural stem cell (NSC) differentiation have not been investigated until now. Here we investigated the effects of...
The effects of the vitamin E isomer δ-tocopherol on neural stem cell (NSC) differentiation have not been investigated until now. Here we investigated the effects of δ-tocopherol on NSC neural differentiation, maturation and its possible mechanisms. Neonatal rat NSCs were grown in suspended neurosphere cultures, and were identified by their expression of nestin protein and their capacity for self-renewal. Treatment with a low concentration of δ-tocopherol induced a significant increase in the percentage of β-III-tubulin-positive cells. δ-Tocopherol also stimulated morphological maturation of neurons in culture. We further observed that δ-tocopherol stimulation increased the expression of voltage-dependent Ca(2+) channels. Moreover, a L-type specific Ca(2+) channel blocker verapamil reduced the percentage of differentiated neurons after δ-tocopherol treatment, and blocked the effects of δ-tocopherol on NSC differentiation into neurons. Together, our study demonstrates that δ-tocopherol may act through elevation of L-type calcium channel activity to increase neuronal differentiation.
Topics: Animals; Animals, Newborn; Calcium Channel Blockers; Calcium Channels, L-Type; Cell Differentiation; Cells, Cultured; Neural Stem Cells; Neurons; Rats, Wistar; Tocopherols; Verapamil; Vitamins
PubMed: 25445352
DOI: 10.1016/j.neulet.2014.11.031 -
Cancer Prevention Research... Nov 2012Tocopherol, a member of the vitamin E family, consists of four forms designated as α, β, γ, and δ. Several large cancer prevention studies with α-tocopherol have...
Tocopherol, a member of the vitamin E family, consists of four forms designated as α, β, γ, and δ. Several large cancer prevention studies with α-tocopherol have reported no beneficial results, but recent laboratory studies have suggested that δ- and γ-tocopherol may be more effective. In two different animal models of breast cancer, the chemopreventive activities of individual tocopherols were assessed using diets containing 0.3% of tocopherol (α-, δ-, or γ-) or 0.3% of a γ-tocopherol rich mixture (γ-TmT). Although administration of tocopherols did not prevent human epidermal growth factor receptor 2 (HER2/neu)-driven tumorigenesis, δ- and γ-tocopherols inhibited hormone-dependent mammary tumorigenesis in N-methyl-N-nitrosourea (NMU)-treated female Sprague-Dawley rats. NMU-treated rats showed an average tumor burden of 10.6 ± 0.8 g in the control group at 11 weeks, whereas dietary administration of δ- and γ-tocopherols significantly decreased tumor burden to 7.2 ± 0.8 g (P < 0.01) and 7.1 ± 0.7 g (P < 0.01), respectively. Tumor multiplicity was also reduced in δ- and γ-tocopherol treatment groups by 42% (P < 0.001) and 32% (P < 0.01), respectively. In contrast, α-tocopherol did not decrease tumor burden or multiplicity. In mammary tumors, the protein levels of proapoptotic markers (BAX, cleaved caspase-9, cleaved caspase-3, cleaved PARP) were increased, whereas antiapoptotic markers (Bcl-2, XIAP) were inhibited by δ-tocopherol, γ-tocopherol, and γ-TmT. Furthermore, markers of cell proliferation (PCNA, PKCα), survival (PPAR-γ, PTEN, phospho-Akt), and cell cycle (p53, p21) were affected by δ- and γ-tocopherols. Both δ- and γ-tocopherols, but not α-tocopherol, seem to be promising agents for the prevention of hormone-dependent breast cancer.
Topics: Animals; Breast Neoplasms; Carcinoma; Cell Transformation, Neoplastic; Dietary Supplements; Disease Models, Animal; Down-Regulation; Female; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Rats; Rats, Sprague-Dawley; Receptor, ErbB-2; Receptors, Estrogen; Tocopherols; gamma-Tocopherol
PubMed: 22964476
DOI: 10.1158/1940-6207.CAPR-12-0263 -
Cancer Prevention Research... Apr 2012The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention....
The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention. Herein, we compared the activities of δ-tocopherol (δ-T), γ-T, and α-T in a colon carcinogenesis model. Male F344 rats, seven weeks old, were given two weekly subcutaneous injections of azoxymethane (AOM) each at a dose of 15 mg/kg body weight. Starting 1 week before the AOM injection, the animals were maintained on a modified AIN76A diet, or the same diet containing 0.2% of δ-T, γ-T, α-T, or a γ-T-rich mixture of tocopherols (γ-TmT), until the termination of the experiment at 8 weeks after the second AOM injection. δ-T treatment showed the strongest inhibitory effect, decreasing the numbers of aberrant crypt foci by 62%. γ-T and γ-TmT were also effective, but α-T was not. Immunohistochemical analysis showed that δ-T and γ-T treatments reduced the levels of 4-hydroxynonenal and nitrotyrosine and the expression of cyclin D1 in the colon, preserved the expression of PPAR-γ, and decreased the serum levels of prostaglandin E2 and 8-isoprostane. Supplementation with 0.2% δ-T, γ-T, or α-T increased the respective levels of tocopherols and their side-chain degradation metabolites in the serum and colon tissues. Rather high concentrations of δ-T and γ-T and their metabolites were found in colon tissues. Our study provides the first evidence for the much higher cancer preventive activity of δ-T and γ-T than α-T in a chemically induced colon carcinogenesis model. It further suggests that δ-T is more effective than γ-T.
Topics: Aldehydes; Animals; Anticarcinogenic Agents; Azoxymethane; Colonic Neoplasms; Cyclin D1; Dinoprost; Dinoprostone; Immunohistochemistry; Male; Models, Chemical; Rats; Rats, Inbred F344; Tocopherols; Tyrosine; alpha-Tocopherol; gamma-Tocopherol
PubMed: 22366914
DOI: 10.1158/1940-6207.CAPR-11-0521 -
Turkish Journal of Urology Jul 2019Obstructive bladder dysfunction (OBD) caused by benign prostatic hyperplasia is a common medical problem in ageing men. As the prostate enlarges and compresses the...
OBJECTIVE
Obstructive bladder dysfunction (OBD) caused by benign prostatic hyperplasia is a common medical problem in ageing men. As the prostate enlarges and compresses the urethra, the bladder wall thickness and the bladder is termed "compensated" because its function is still relatively normal. Subsequently, bladder function begins to fail and this change is termed "decompensation." The extent of decompensation progresses from mild through severe. Bladder decompensation is mediated by cyclical ischemia followed by reperfusion (I/R) resulting in an increased generation of free radicals and oxidative stress. Previous studies demonstrated that both vitamin E (tocopherol) and alpha-lipoic acid (LA) showed significant antioxidant activity in experimental urinary bladder oxidative stress models. We hypothesized that co-drugs derived from these antioxidants would result in enhanced antioxidant activity relative to either individual compound for the treatment of oxidative stress in the lower urinary tract.
MATERIAL AND METHODS
Two ester co-drugs of TOC and LA, tocopherol ester (α-TOCE) and δ-TOCE were synthesized. Six adult male New Zealand White (NZW) rabbits were divided into two groups of three rabbits each. Eight full thickness strips from each rabbit bladder were taken for in vitro I/R experiments. The strips from the first set were control rabbits (24 strips). Six strips were not incubated, while the remaining strips were incubated in α-TOCE dissolved in 1% (n=6) or 2.5% ethanol (n=6) solutions. These strips were not subjected to in vitro I/R. The strips from the second set were processed as follows: 6 strips were not incubated, while the remaining strips were incubated in α-TOCE dissolved in 1% (n=6) or in δ-TOCE dissolved in 2.5% ethanol. These strips were subjected to 1 hour in vitro ischemia followed by two hours reperfusion.
RESULTS
Preliminary studies demonstrated that neither antioxidant had any effect on the contractile responses to 1% or 2.5% ethanol. Neither antioxidant had any effect on the control contractile responses. Both antioxidants protected the tissue from the initial effects of ischemia. Both antioxidants had significant protective effects on the contractile responses to all forms of stimulation after the reperfusion period.
CONCLUSION
Incubation with both antioxidants had similar protective effects on responses both to ischemia and to reperfusion.
PubMed: 30817293
DOI: 10.5152/tud.2018.48154 -
Nutrients Jun 2012Vitamin E isoforms are essential nutrients that are widely used as dietary supplements and therapeutic agents for a variety of diseases. However, their pharmacokinetic...
Vitamin E isoforms are essential nutrients that are widely used as dietary supplements and therapeutic agents for a variety of diseases. However, their pharmacokinetic (PK) properties remain poorly characterized, and high dosage animal studies may provide further information on their in vivo functions and pharmacological effects. In this study, alpha-tocopherol (α-toc) and delta-tocopherol (δ-toc) levels were measured in mouse plasma and tissues following their high dosage dietary supplementation. Average α-toc levels at 5, 10 and 20 g α-toc/kg diet increased over baseline levels 6-fold in plasma, 1.6-fold in brain, and 4.9-fold in liver. These elevated α-toc concentrations remained constant from 5 to 20 g α-toc/kg diet, rather than showing further increases across these dosages. No α-toc-related toxicity occurred at these high dosages, and strain-specific differences in liver and brain α-toc levels between Balb/cJ and C57Bl/6J mice were observed. Relatively high-dosage administration of dietary δ-toc for 1 or 4 weeks resulted in 6-30-fold increases in plasma and liver levels between dosages of 0.33 and 1.67 g δ-toc/kg diet. Co-administration of sesamin with δ-toc further increased δ-toc levels between 1.3- and 14-fold in plasma, liver, and brain. These results provide valuable PK information on high dosage α-toc and δ-toc in mouse and show that supplementation of sesamin with δ-toc further increases δ-toc levels over those seen with δ-toc supplementation alone.
Topics: Adipose Tissue; Animals; Antioxidants; Brain Chemistry; Dietary Supplements; Dioxoles; Lignans; Liver; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Tocopherols; Vitamin E; Vitamin E Deficiency; Vitamins; alpha-Tocopherol
PubMed: 22822447
DOI: 10.3390/nu4060467 -
The Biochemical Journal Apr 1998alpha-Tocopherol transfer protein (alpha-TTP) supplements nascent very-low-density lipoprotein (VLDL) preferentially with alpha-tocopherol by selecting the alpha-isomers...
alpha-Tocopherol transfer protein (alpha-TTP) supplements nascent very-low-density lipoprotein (VLDL) preferentially with alpha-tocopherol by selecting the alpha-isomers against other stereoisomers of tocopherol. It is exclusively expressed in liver. We investigated whether the expression of the hepatic alpha-TTP can be induced by dietary tocopherols. Vitamin E-depleted rats were fed with a diet containing alpha- and delta-tocopherol (ratio 1:3). The expression of alpha-TTP mRNA was measured in liver tissue. The ratio of tocopherol stereoisomers was determined in plasma, plasma lipoproteins and tissues to measure the metabolic action of alpha-TTP. Refeeding a diet containing either alpha- or delta-tocopherol, or both, caused a steady increase of the expression of alpha-TTP mRNA. In parallel the alpha/delta-tocopherol ratio increased in plasma, VLDL, high-density lipoprotein and low-density lipoprotein as well as in liver tissue, when the diet was fed containing both isomers. The alpha-tocopherol/delta-tocopherol ratio of heart, kidney, lung, lamellar bodies of lung and in lung lavage showed no or a comparatively low increase. The data show that both tocopherol isomers were able to induce alpha-TTP mRNA in rat liver and, thus, the ability of liver to select for the alpha-isomer. On the other hand, tocopherol depletion did not change the expression of hepatic alpha-TTP mRNA in the rat.
Topics: Animals; Blotting, Northern; Carrier Proteins; Diet; Gene Expression; Lipoproteins; Liver; Lung; RNA, Messenger; Rats; Stereoisomerism; Vitamin E
PubMed: 9531500
DOI: 10.1042/bj3310577 -
Journal of Lipid Research Jan 1984A novel metabolite of d-delta-tocopherol was isolated from the urine of rats given d-3,4-[3H2]-delta-tocopherol intravenously. The metabolite was collected from the...
A novel metabolite of d-delta-tocopherol was isolated from the urine of rats given d-3,4-[3H2]-delta-tocopherol intravenously. The metabolite was collected from the urine of rats given d-delta-tocopherol in the same manner as that of the labeled compound. It was found that the metabolites consisted of sulfate conjugates. The portion of the major metabolite released with sulfatase was determined to be 2,8-dimethyl-2-(2'-carboxyethyl)-6-chromanol by infrared spectra, nuclear magnetic resonance spectra, and mass spectra. The proposed structure was confirmed by comparing the analytical results with those of a synthetically derived compound. As a result of the structural elucidation of this novel metabolite, a pathway for the biological transformation of delta-tocopherol is proposed which is different from that of alpha-tocopherol. A characteristic feature of the pathway is the absence of any opening of the chroman ring throughout the sequence.
Topics: Animals; Carbon Radioisotopes; Indicators and Reagents; Kinetics; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Rats; Rats, Inbred Strains; Spectrophotometry, Infrared; Tocopherols; Tritium; Vitamin E
PubMed: 6707520
DOI: No ID Found -
Journal of the American College of... Aug 2006Vitamin E consists of a group of eight isomers, four tocopherols (alpha-, beta-, gamma-, delta-tocopherol) and four tocotrienols (alpha-, beta-, gamma-,... (Review)
Review
Vitamin E consists of a group of eight isomers, four tocopherols (alpha-, beta-, gamma-, delta-tocopherol) and four tocotrienols (alpha-, beta-, gamma-, delta-tocotrienol). While extensive literature has been published on the potential health benefits of alpha-tocopherol, little is known about gamma-tocopherol, the major form of vitamin E in food in the U.S. gamma-tocopherol has recently received more research attention based on findings from in vitro and animal studies indicating that it has potent anti-inflammatory and antioxidant properties. Based on these recent studies, it is important to investigate the possible health benefits of gamma-tocopherol in humans. In this article, we review publications on dietary gamma-tocopherol intake, plasma gamma-tocopherol levels, cardiovascular disease and cancer risk in humans.
Topics: Diet; Heart Diseases; Humans; Neoplasms; Vitamins; gamma-Tocopherol
PubMed: 16943450
DOI: 10.1080/07315724.2006.10719538 -
Antioxidants (Basel, Switzerland) Mar 2014Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have...
Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have been attributed to some isomers, such as anticarcinogenic activity, antiartherosclerotic effects and reduction of body fat gain. Hence, oils rich in CLA such as Tonalin(®) oil (TO), normally obtained through alkaline isomerization of safflower oil (SO), an oil rich in linoleic acid (LA), are currently used in functional foods. However, special care must be taken to protect them from oxidation to ensure the quality of the supplemented foods. The objective of this work was to evaluate the oxidation and effectiveness of different tocopherol homologues (α-, γ- and δ-), alone or in combination with synergists (ascorbyl palmitate and lecithin), in TO compared to SO at different conditions, ambient temperature (25 °C) and accelerated conditions in Rancimat (100 °C). The oils, the oils devoid of their antioxidants and the latter containing the antioxidants added were assayed. Results showed great differences between SO and TO in terms of formation of hydroperoxides and polymers and also in the effectiveness of tocopherols to delay oxidation. TO showed higher levels of polymerization and, in general, the effectiveness of tocopherol homologues, alone or in combination with synergists, was also lower in the TO.
PubMed: 26784671
DOI: 10.3390/antiox3010176 -
Critical Reviews in Food Science and... 2016Fish products contain various nutritionally beneficial components, namely, ω3-polyunsaturated fatty acids (ω3-PUFA), minerals, and vitamins. Particularly, tocopherols... (Review)
Review
Fish products contain various nutritionally beneficial components, namely, ω3-polyunsaturated fatty acids (ω3-PUFA), minerals, and vitamins. Particularly, tocopherols (α-, β-, γ-, and δ-tocopherol) can be provided by seafood and aquaculture products. Hence, this review shows the various aspects of tocopherols in seafood and aquaculture products. For tocopherol determination in these products, HPLC methods coupled with diode array detection in the UV area of the spectrum or fluorescence detection have been shown as sensitive and accurate. These newest methods have helped in understanding tocopherols fate upon ingestion by seafood organisms. Tocopherols pass through the intestinal mucosa mainly by the same passive diffusion mechanism as fats. After absorption, the transport mechanism is thought to consist of two loops. The first loop is dietary, including chylomicrons and fatty acids bound to carrier protein, transporting lipids mainly to the liver. The other is the transport from the liver to tissues and storage sites. Moreover, tocopherol levels in fish organisms correlate with diet levels, being adjusted in fish body depending on diet concentration. For farmed fish species, insufficient levels of tocopherols in the diet can lead to poor growth performance or to nutritional disease. The tocopherol quantity needed as a feed supplement depends on various factors, such as the vitamer mixture, the lipid level and source, the method of diet preparation, and the feed storage conditions. Other ingredients in diet may be of great importance, it has been proposed that α-tocopherol may behave as a prooxidant synergist at higher concentrations when prooxidants such as transition metals are present. However, the antioxidant action of tocopherols outweighs this prooxidant effect, provided that adequate conditions are used. In fact, muscle-based foods containing higher levels of tocopherol show, for instance, higher lipid stability. Besides, tocopherols are important not only from the nutritional point of view but also from the physiological one, since they are involved in many metabolic processes in the human organism. Moreover, synergistic interactions with selenium and ascorbic acid have been reported. It deserves attention that there is evidence tocopherols taken with food can prevent heart disease, while no such evidence was found for α-tocopherol as supplement. From this perspective, eating fish is advisable, since, for instance, a 100 g serving of salmon may provide nearly 14% of recommended dietary allowance.
Topics: Animals; Antioxidants; Aquaculture; Aquatic Organisms; Fish Products; Fishes; Food Handling; Food Storage; Functional Food; Humans; Nutrition Policy; Nutritive Value; Seafood; Shellfish; Tocopherols
PubMed: 24915325
DOI: 10.1080/10408398.2012.694920