tocotrienol--delta and plastochromanol-8

Initial research on vitamin E and cancer has focused on α-tocopherol (αT), but recent clinical studies on cancer-preventive effects of αT supplementation have shown disappointing results, which has led to doubts about the role of vitamin E, including different vitamin E forms, in cancer prevention. However, accumulating mechanistic and preclinical animal studies show that other forms of vitamin E, such as γ-tocopherol (γT), δ-tocopherol (δT), γ-tocotrienol (γTE), and δ-tocotrienol (δTE), have far superior cancer-preventive activities than does αT. These vitamin E forms are much stronger than αT in inhibiting multiple cancer-promoting pathways, including cyclo-oxygenase (COX)- and 5-lipoxygenase (5-LOX)-catalyzed eicosanoids, and transcription factors such as nuclear transcription factor κB (NF-κB) and signal transducer and activator of transcription factor 3 (STAT3). These vitamin E forms, but not αT, cause pro-death or antiproliferation effects in cancer cells via modulating various signaling pathways, including sphingolipid metabolism. Unlike αT, these vitamin E forms are quickly metabolized to various carboxychromanols including 13'-carboxychromanols, which have even stronger anti-inflammatory and anticancer effects than some vitamin precursors. Consistent with mechanistic findings, γT, δT, γTE, and δTE, but not αT, have been shown to be effective for preventing the progression of various types of cancer in preclinical animal models. This review focuses on cancer-preventive effects and mechanisms of γT, δT, γTE, and δTE in cells and preclinical models and discusses current progress in clinical trials. The existing evidence strongly indicates that these lesser-known vitamin E forms are effective agents for cancer prevention or as adjuvants for improving prevention, therapy, and control of cancer.

Topics: Animals; Antineoplastic Agents; Carcinogenesis; Chromans; gamma-Tocopherol; Humans; Neoplasms; Signal Transduction; Tocopherols; Vitamin E; Vitamins

Tocotrienols (T3s) are a subclass of unsaturated vitamin E that have been extensively studied for their anti-proliferative, anti-oxidative and anti-inflammatory properties in numerous cancer studies. Recently, T3s have received increasing attention due to their previously unrecognized property to attenuate obesity and its associated metabolic complications. In this review, we comprehensively evaluated the recent published scientific literature about the influence of T3s on obesity, with a particular emphasis on the signaling pathways involved. T3s have been demonstrated in animal models or human subjects to reduce fat mass, body weight, plasma concentrations of free fatty acid, triglycerides and cholesterol, as well as to improve glucose and insulin tolerance. Their mechanisms of action in adipose tissue mainly include (1) modulation of fat cell adipogenesis and differentiation; (2) modulation of energy sensing; (3) induction of apoptosis in preadipocytes and (4) modulation of inflammation. Studies have also been conducted to investigate the effects of T3s on other targets, e.g., the immune system, liver, muscle, pancreas and bone. Since δT3 and γT3 are regarded as the most active isomers among T3s, their clinical relevance to reduce obesity should be investigated in human trials.

Topics: Adipogenesis; Adipose Tissue; Animals; Anti-Obesity Agents; Apoptosis; Biological Availability; Chromans; Energy Metabolism; Humans; Immunomodulation; Inflammation; Liver; Obesity; Signal Transduction; Vitamin E

Gamma and delta tocotrienols are isomers of Vitamin E with established potency in pre-clinical anti-cancer research. This single-dose, randomized, crossover study aimed to compare the safety and bioavailability of a new formulation of Gamma Delta Tocotrienol (GDT) in comparison with the existing Tocotrienol-rich Fraction (TRF) in terms of gamma and delta isomers in healthy volunteers. Subjects were given either two 300 mg GDT (450 mg γ-T3 and 150 mg δ-T3) capsules or four 200 mg TRF (451.2 mg γ-T3 &102.72 mg δ-T3) capsules and blood samples were taken at several time points over 24 hours. Plasma tocotrienol concentrations were determined using HPLC method. The 90% CI for gamma and delta tocotrienols for the ratio of log-transformation of GDT/TRF for Cmax and AUC0-∞ (values were anti-logged and expressed as a percentage) were beyond the bioequivalence limits (106.21-195.46, 154.11-195.93 and 52.35-99.66, 74.82-89.44 respectively). The Wilcoxon Signed Rank Test for Tmax did not show any significant difference between GDT and TRF for both isomers (p > 0.05). No adverse events were reported during the entire period of study. GDT was found not bioequivalent to TRF, in terms of AUC and Cmax. Gamma tocotrienol in GDT showed superior bioavailability whilst delta tocotrienol showed less bioavailability compared to TRF.

Topics: Adult; Analysis of Variance; Area Under Curve; Biological Availability; Chromans; Chromatography, High Pressure Liquid; Cross-Over Studies; Drug Compounding; Female; Half-Life; Healthy Volunteers; Humans; Isomerism; Male; ROC Curve; Tocotrienols; Vitamin E; Young Adult

We have investigated the pharmacokinetics and bioavailability of alpha-, gamma- and delta-tocotrienols under fed and fasted conditions in eight healthy volunteers. The volunteers were administered a single oral dose of mixed tocotrienols (300 mg) under fed or fasted conditions. The bioavailability of tocotrienols under the two conditions was compared using the parameters peak plasma concentration (Cmax), time to reach peak plasma concentration (Tmax) and total area under the plasma concentration-time curve (AUC(o-infinity)). A statistically significant difference was observed between the fed and fasted logarithmic transformed values of Cmax (P < 0.01) and AUC(0-infinity) (P < 0.01) for all three tocotrienols. In addition, the 90% confidence intervals for the ratio of the logarithmic transformed AUC(0-infinity) values of alpha-, gamma- and delta-tocotrienols under the fed state over those of the fasted state were found to lie between 2.24-3.40, 2.05-4.09 and 1.59-3.81, respectively, while those of the Cmax were between 2.28-4.39, 2.31-5.87 and 1.52-4.05, respectively. However, no statistically significant difference was observed between the fed and fasted Tmax values of the three homologues. The mean apparent elimination half-life (t(1/2)) of alpha-, gamma- and delta-tocotrienols was estimated to be 4.4, 4.3 and 2.3 h, respectively, being between 4.5- to 8.7-fold shorter than that reported for alpha-tocopherol. No statistically significant difference was observed between the fed and fasted t(1/2) values. The mean apparent volume of distribution (Vd/f) values under the fed state were significantly smaller than those of the fasted state, which could be attributed to increased absorption of the tocotrienols in the fed state.

Topics: Administration, Oral; Adult; Antioxidants; Area Under Curve; Biological Availability; Chromans; Eating; Fasting; Half-Life; Humans; Male; Middle Aged; Tocotrienols; Vitamin E

Previous studies have demonstrated the anticancer activities of tocotrienol on several types of cancer, but its effects on chondrosarcoma have never been investigated. Therefore, this study aims to determine the anticancer properties of annatto tocotrienol (AnTT), γ-tocotrienol (γ-T3) and δ-tocotrienol (δ-T3) on human chondrosarcoma SW1353 cells. Firstly, the MTT assay was performed to determine the half-maximal inhibitory concentration (IC

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Chondrosarcoma; Humans; Tocotrienols; Transcriptome; Vitamin E

Senescence is an irreversible permanent cell cycle arrest accompanied by changes in cell morphology and physiology. Bioactive compounds including tocotrienols (vitamin E) can affect important biological functions. The aim of this study was to investigate how γ- and δ-tocotrienols can affect stress-induced premature senescence. We established two different models of premature stress senescence by induction of senescence with either hydrogen peroxide or etoposide in human lung fibroblasts MRC-5 (ECACC, England). We observed increased percentage of cells with increased SA-β-galactosidase activity, decreased cell viability/proliferation and increased level of p21 in both models. In addition, γ-tocotrienol or δ-tocotrienol (both at concentrations of 150, 200 and 300 μM) were added to the cells along with the inductor of senescence (cotreatment). We have found that this cotreatment led to the decrease of cell viability/proliferation in both models of premature stress senescence, but did not change the percentage of senescent cells. Moreover, we detected no expression of caspase-3 or apoptotic DNA fragmentation in any models of premature stress senescence after the cotreatment with γ- as well as δ-tocotrienols. However, an increased level of autophagic protein LC-3 II was detected in cells with hydrogen peroxide-induced senescence after the cotreatment with γ-tocotrienol as well as δ-tocotrienol. In case of etoposide-induced senescence only δ-tocotrienol cotreatment led to an increased level of LC-3 II protein in cells. According to our work δ-tocotrienol is more effective compound than γ-tocotrienol.

Topics: Apoptosis; Autophagy; Cell Survival; Cells, Cultured; Cellular Senescence; Chromans; Fibroblasts; Humans; Microtubule-Associated Proteins; Vitamin E

Tocotrienols have been reported to have stronger bioactivities than tocopherols, and may therefore be suitable as a potent source of vitamin E in functional foods, supplements, and pharmaceuticals. However, their inclusion into new products is hindered by their low water-solubility and oral bioavailability. Oil-in-water emulsions (O/W) could provide an adequate delivery system for these bioactive compounds. Tocotrienols were tested in bulk oil and within O/W conventional emulsions (>10μm) and nanoemulsions (<350nm). The emulsions were prepared with medium chain triglycerides (MCT) as an oil phase (5 to 40% wt) and quillaja saponins as a natural surfactant. The gastrointestinal fate of the emulsion-based delivery systems was investigated using a simulated gastrointestinal tract (GIT). The physical properties of the emulsions (color, apparent viscosity) were affected with increased droplet concentration. The lipid phase composition (emulsion type and particle size) had a pronounced impact on the microstructure of the emulsions in different regions of the GIT. At simulated small intestine conditions, the rate of lipid digestion and tocotrienol bioaccessibility decreased in the following order: nanoemulsions>emulsions>bulk oil. These results suggest that emulsions containing small lipid droplets are particularly suitable for delivering tocotrienols.

Topics: Chromans; Color; Emulsions; Gastric Juice; Hydrogen-Ion Concentration; Intestinal Secretions; Nanoparticles; Particle Size; Quillaja Saponins; Surface Properties; Surface-Active Agents; Triglycerides; Viscosity; Vitamin E; Water

Tocotrienols (T3) are the naturally occurring vitamin E derivatives that possess antioxidant properties and therapeutic potential in diabetic complications. The bioactivities of the derivatives are determined by the number and arrangement of methyl substitution on the structure.. The objective of this study was to determine the effects of T3 derivatives, σ-T3, γ-T3 and α-T3 on insulin secretion of rat pancreatic islets in a dynamic culture.. Pancreatic islets isolated from male Wistar rats were treated with T3 for 1 h at 37°C in a microfluidic system with continuous operation that provided a stable cell culture environment. Glucose (2.8 mM and 16.7 mM, as basal and stimulant, respectively) and potassium chloride (KCl) (30 mM) were added to the treatment in calcium free medium. The supernatant was collected for insulin measurements.. Short-term exposure (1 h) of σ-T3 to β cells in the stimulant glucose condition significantly potentiated insulin secretion in a dose-dependent manner. γ-T3 and α-T3 also displayed dosedependent effect but were less effective in the activation of insulin secretion. Essentially, KCl, a pancreatic β cell membrane depolarizing agent, added into the treatment further enhanced the insulin secretion of σ-T3, γ-T3 and α-T3 with ED50 values of 504, 511 and 588 µM, respectively.. The findings suggest the potential of σ-T3 in regulating glucose-stimulated insulin secretion (GSIS) in response to the intracellular calcium especially in the presence of KCl.

Topics: Animals; Antioxidants; Chromans; Dose-Response Relationship, Drug; Glucose; In Vitro Techniques; Insulin; Insulin Secretion; Islets of Langerhans; Male; Potassium Chloride; Rats; Rats, Wistar; Tissue Culture Techniques; Tocotrienols; Vitamin E

There are six tocol analogs present in palm oil, namely α-tocopherol (α-T), α-tocomonoenol (α-T₁), α-tocotrienol (α-T₃), γ-tocotrienol (γ-T₃), β-tocotrioenol (β-T₃) and δ-tocotrienol (δ-T₃). These analogs were difficult to separate chromatographically due to their similar structures, physical and chemical properties. This paper reports on the effect of pressure and injection solvent on the separation of the tocol analogs in palm oil. Supercritical CO₂ modified with ethanol was used as the mobile phase. Both total elution time and resolution of the tocol analogs decreased with increased pressure. Ethanol as an injection solvent resulted in peak broadening of the analogs within the entire pressure range studied. Solvents with an eluent strength of 3.4 or less were more suitable for use as injecting solvents.

Topics: alpha-Tocopherol; Chromans; Chromatography, Supercritical Fluid; Molecular Structure; Palm Oil; Pressure; Solvents; Tocopherols; Tocotrienols; Vitamin E

Tocotrienols (T3s) and tocopherols (Tocs) are both members of the vitamin E family. It is known that δ-tocotrienol (δ-T3) has displayed the most potent anti-cancer activity amongst the tocotrienols. On the other hand, γ-tocopherol (γ-Toc) is reported to have a protective effect against prostate cancer. Therefore, we investigated whether the combination of γ-Toc and δ-T3 could strengthen the inhibitory effect of δ-T3 on prostate cancer cell growth. In this study the effect of combined δ-T3 (annatto T3 oil) and γ-Toc (Tmix, γ-Toc-rich oil) therapy was assessed against human androgen-dependent prostate cancer cells (LNCaP). We found that combined treatment of δ-T3 (10 μM) and γ-Toc (5 μM) resulted in reinforced anti-prostate cancer activity. Specifically, cell cycle phase distribution analysis revealed that in addition to G1 arrest caused by the treatment with δ-T3, the combination of δ-T3 with γ-Toc induced G2/M arrest. Enhanced induction of apoptosis by the combined treatment was also observed. These findings indicate that combination of δ-T3 and γ-Toc significantly inhibits prostate cancer cell growth due to the simultaneous cell cycle arrest in the G1 phase and G2/M phase.

Topics: Anticarcinogenic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Bixaceae; Carotenoids; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chromans; G1 Phase; G2 Phase; Humans; Male; Osmolar Concentration; Plant Extracts; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Vitamin E

We have developed a method for analysing vitamin E using ultra-performance convergence chromatography with a chromatographic runtime of 5.5 min. A well-resolved chromatogram with excellent precision in retention time revealed seven vitamin E components in the palm oil derived tocotrienol-rich fraction. The major vitamin E components were α-tocopherol, α-tocotrienol, γ-tocotrienol and δ-tocotrienol whereas the minor vitamin E components were α-tocomonoenol, β-tocotrienol and an unreported trace component. The new component was positively identified by high-resolution mass spectrometry as 2-methyl-2(4',8',12'-trimethyltrideca-7',11'-dienyl)5,7,8-trimethylchroman-6-ol or α-tocodienol.

Topics: alpha-Tocopherol; Chromans; Chromatography, High Pressure Liquid; Mass Spectrometry; Palm Oil; Plant Oils; Tocotrienols; Vitamin E

Tocotrienol (T3) has recently gained increasing interest due to its anti-cancer effect. Here, we investigated the modulating effect of δ and γ T3 on the Ras-Raf-MEK-ERK oncogenic upstream signaling pathway in human hepatocellular carcinoma HepG2 cells. The results indicated that T3 regulated the upstream signaling cascades of this pathway.

Topics: Carcinoma, Hepatocellular; Cell Proliferation; Chromans; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Liver Neoplasms; MAP Kinase Kinase Kinases; raf Kinases; ras Proteins; Signal Transduction; Vitamin E

The impact of supplementing laying-hen feed with annatto tocotrienols (T3s) and alpha-tocopherol on the distribution of various forms of vitamin E and cholesterol throughout the hen's body was evaluated. A total of 18 organs or tissues (skin, fat pad, liver and gall bladder, heart, oviduct, forming yolk, laid yolk, lungs, spleen, kidney, pancreas, gizzard, digestive tract, brain, thigh, breast, manure, and blood) were collected after 7 wk of feeding on diets enriched with various levels of alpha-tocopherol and annatto extract that contained gamma-T3 and delta-T3. Tissue weights, contents of lipid, alpha-tocopherol, gamma-T3, delta-T3, cholesterol, and fatty acid composition of extracted lipids from the collected organs and tissues were determined. Tissue weight and lipid content did not change significantly with feed supplementation treatments, except that the liver became heavier with increased levels of supplementation. Overall, the main organs that accumulated the supplemented vitamin E were fat pad, liver and gall bladder, oviduct, forming yolks, laid yolks, kidney, brain, thigh, and breast. Much of annatto gamma-T3 and delta-T3 (> 90%) was found in the manure, indicating poor uptake. In some tissues (brain and oviduct,) a significant increase in polyunsaturated fatty acids was seen with increased supplementation. Alpha-tocopherol impacted the transfer of gamma-T3 to forming and laid yolks, but did not impact delta-T3 transfer. No significant differences were found in most of the tissues in cholesterol, except a reduction in heart, based on tissue as-is. Blood samples showed large variations in individual hens with no significant differences in total and HDL cholesterol, or total triacylglycerols. Supplementing feed with annatto T3s and alpha-tocopherol showed that the vitamin E profile and distribution of the laying-hen body can be altered, but to different extents depending on tissue. The result of this research has significance in enhancing meat nutrient content.

Topics: alpha-Tocopherol; Animal Feed; Animals; Bixaceae; Carotenoids; Chickens; Cholesterol; Chromans; Diet; Dietary Supplements; Female; Liver; Plant Extracts; Random Allocation; Tissue Distribution; Vitamin E

Oxazine derivatives of tocotrienols display enhanced anticancer activity. Studies were conducted to further characterize these effects in vivo.. Tetrazolium assay was used to determine the inhibitory effects of oxazine derivatives of γ-tocotrienol and δ-tocotrienol in vitro. These compounds were further formulated as lipid nanoemulsions and intralesional administration was used to examine their anticancer activity in vivo.. Tocotrienol oxazine derivatives significantly inhibited +SA mammary tumor growth in syngeneic mice as compared to their respective parent compound, and these effects were associated with a reduction in cell proliferation and survival (phosphorylated protein kinase B (AKT) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and cyclooxygenase-2 (COX2) and cell-cycle progression (cyclin D1, cyclin-dependent kinase 2 (CDK2), CDK4 and CDK6) markers, and increase in cell-cycle arrest proteins (p21 and p27).. Tocotrienol oxazine derivatives may provide benefit as therapeutic agents against breast cancer.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Biomarkers, Tumor; Blotting, Western; Cell Proliferation; Chromans; Female; Mammary Neoplasms, Animal; Mice; Mice, Inbred BALB C; Oxazines; Vitamin E

Measurements of the singlet oxygen ((1)O2) quenching rates (kQ (S)) and the relative singlet oxygen absorption capacity (SOAC) values were performed for 11 antioxidants (AOs) (eight vitamin E homologues (α-, β-, γ-, and δ-tocopherols and -tocotrienols (-Tocs and -Toc-3s)), two vitamin E metabolites (α- and γ-carboxyethyl-6-hydroxychroman), and trolox) in ethanol/chloroform/D2O (50:50:1, v/v/v) and ethanol solutions at 35 °C. Similar measurements were performed for five palm oil extracts 1-5 and one soybean extract 6, which included different concentrations of Tocs, Toc-3s, and carotenoids. Furthermore, the concentrations (wt%) of Tocs, Toc-3s, and carotenoids included in extracts 1-6 were determined. From the results, it has been clarified that the (1)O2-quenching rates (kQ (S)) (that is, the relative SOAC value) obtained for extracts 1-6 may be explained as the sum of the product {Σ kQ(AO-i) (S) [AO-i]/100} of the rate constant (kQ(AO-i) (S)) and the concentration ([AO-i]/100) of AO-i (Tocs, Toc-3s, and carotenoid) included.

Topics: Carotenoids; Chromans; Free Radical Scavengers; Glycine max; Kinetics; Palm Oil; Plant Extracts; Plant Oils; Singlet Oxygen; Solutions; Tocopherols; Tocotrienols; Vitamin E

Tocotrienols, especially the gamma isomer was discovered to possess cytotoxic effects associated with the induction of apoptosis in numerous cancers. Individual tocotrienol isomers are believed to induce dissimilar apoptotic mechanisms in different cancer types. This study was aimed to compare the cytotoxic potency of alpha-, gamma- and delta-tocotrienols, and to explore their resultant apoptotic mechanisms in human lung adenocarcinoma A549 and glioblastoma U87MG cells which are scarcely researched.. The cytotoxic effects of alpha-, gamma- and delta-tocotrienols in both A549 and U87MG cancer cells were first determined at the cell viability and morphological aspects. DNA damage types were then identified by comet assay and flow cytometric study was carried out to support the incidence of apoptosis. The involvements of caspase-8, Bid, Bax and mitochondrial membrane permeability (MMP) in the execution of apoptosis were further expounded.. All tocotrienols inhibited the growth of A549 and U87MG cancer cells in a concentration- and time-dependent manner. These treated cancer cells demonstrated some hallmarks of apoptotic morphologies, apoptosis was further confirmed by cell accumulation at the pre-G1 stage. All tocotrienols induced only double strand DNA breaks (DSBs) and no single strand DNA breaks (SSBs) in both treated cancer cells. Activation of caspase-8 leading to increased levels of Bid and Bax as well as cytochrome c release attributed by the disruption of mitochondrial membrane permeability in both A549 and U87MG cells were evident.. This study has shown that delta-tocotrienol, in all experimental approaches, possessed a higher efficacy (shorter induction period) and effectiveness (higher induction rate) in the execution of apoptosis in both A549 and U87MG cancer cells as compared to alpha- and gamma-tocotrienols. Tocotrienols in particular the delta isomer can be an alternative chemotherapeutic agent for treating lung and brain cancers.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Antineoplastic Agents; Antioxidants; Apoptosis; bcl-2-Associated X Protein; BH3 Interacting Domain Death Agonist Protein; Caspase 8; Cell Cycle; Cell Line, Tumor; Cell Survival; Central Nervous System Neoplasms; Chromans; Cytochromes c; DNA Fragmentation; Glioblastoma; Humans; Isomerism; Lung Neoplasms; Mitochondria; Tocotrienols; Vitamin E

Tocotrienols and tocopherols are members of the vitamin E family, with similar structures; however, only tocotrienols have been reported to achieve potent anti-cancer effects. The study described here has evaluated anti-cancer activity of vitamin E to elucidate mechanisms of cell death, using human breast cancer cells.. Anti-cancer activity of a tocotrienol-rich fraction (TRF) and a tocotrienol-enriched fraction (TEF) isolated from palm oil, as well as pure vitamin E analogues (α-tocopherol, α-, δ- and γ-tocotrienols) were studied using highly aggressive triple negative MDA-MB-231 cells and oestrogen-dependent MCF-7 cells, both of human breast cancer cell lines. Cell population growth was evaluated using a Coulter particle counter. Cell death mechanism, poly(ADP-ribose) polymerase cleavage and levels of NF-κB were determined using commercial ELISA kits.. Tocotrienols exerted potent anti-proliferative effects on both types of cell by inducing apoptosis, the underlying mechanism of cell death being ascertained using respective IC50 concentrations of all test compounds. There was marked induction of apoptosis in both cell lines by tocotrienols compared to treatment with Paclitaxel, which was used as positive control. This activity was found to be associated with cleavage of poly(ADP-ribose) polymerase (a DNA repair protein), demonstrating involvement of the apoptotic cell death signalling pathway. Tocotrienols also inhibited expression of nuclear factor kappa-B (NF-κB), which in turn can increase sensitivity of cancer cells to apoptosis.. Tocotrienols induced anti-proliferative and apoptotic effects in association with DNA fragmentation, poly(ADP-ribose) polymerase cleavage and NF-κB inhibition in the two human breast cancer cell lines.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Count; Cell Proliferation; Chromans; DNA Fragmentation; Enzyme-Linked Immunosorbent Assay; Female; Humans; Inhibitory Concentration 50; MCF-7 Cells; NF-kappa B p50 Subunit; Paclitaxel; Palm Oil; Plant Oils; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Proteolysis; Reagent Kits, Diagnostic; Signal Transduction; Tocotrienols; Vitamin E

Stress has been implicated as a risk factor of various major health problems, such as stress-induced gastric mucosal injury. This study was performed to investigate the action of a pure preparation of tocotrienol (T3) concentrate, made up of 90% δ-tocotrienol and 10% γ-tocotrienol, on gastric injury of rats induced by water-immersion restraint stress (WIRS). Fourteen male Sprague-Dawley rats (200-250 g) were divided into two equal groups: a control group and a treated group. The treatment group received T3 concentrate at 60 mg/kg body weight daily for 28 days. The body weights of rats were recorded daily before the treatment was given. At the end of the treatment period, all rats were subjected to WIRS for 3.5 hours, following which the rats were euthanized. The stomachs were isolated and opened along the greater curvature for the examination of lesions and measurements of gastric malondialdehyde (MDA) and prostaglandin E₂ (PGE₂) contents. The mean gastric mucosal lesion index in the treated rats was significantly lower than that in the control rats. This suggests that the T3 concentrate has the ability to confer protection to the gastric mucosa against gastric injury induced by acute stress. No significant difference was observed for changes in body weight before and after the treatment. The gastric PGE2 content in both groups was comparable. However, the gastric MDA content was significantly higher in the treated group compared to the control group, indicating that the T3 supplementation was not able to reduce the lipid peroxidation process. This study concludes that the T3 concentrate has the ability to protect the gastric mucosa from stress-induced injury by a non-antioxidant mechanism.

Topics: Animals; Body Weight; Chromans; Dinoprostone; Gastric Mucosa; Lipid Peroxidation; Male; Malondialdehyde; Oxidative Stress; Rats; Rats, Sprague-Dawley; Stress, Physiological; Vitamin E

Tocotrienols are isomers of the vitamin E family, which have been reported to exert cytotoxic effects in various cancer cells. Although there have been some reports on the effects of tocotrienols in leukemic cells, ultrastructural evidence of tocotrienol-induced apoptotic cell death in leukemic cells is lacking. The present study investigated the effects of three isomers of tocotrienols (alpha, delta, and gamma) on a human T lymphoblastic leukemic cell line (CEM-SS). Cell viability assays showed that all three isomers had cytotoxic effects (p < 0.05) on CEM-SS cells with delta-tocotrienol being the most potent. Transmission electron microscopy showed that the cytotoxic effects by delta- and gamma-tocotrienols were through the induction of an apoptotic pathway as demonstrated by the classical ultrastructural apoptotic changes characterized by peripheral nuclear chromatin condensation and nuclear fragmentation. These findings were confirmed biochemically by the demonstration of phosphatidylserine externalization via flow cytometry analysis. This is the first study showing classical ultrastructural apoptotic changes induced by delta- and gamma-tocotrienols in human T lymphoblastic leukemic cells.

Topics: Apoptosis; Cell Line, Tumor; Cell Nucleus; Cell Survival; Chromans; Chromatin; Humans; Microscopy, Electron, Transmission; T-Lymphocytes; Tocotrienols; Vitamin E

There is growing evidence showing that prostate cancer cells have perturbed cholesterol homoeostasis, accumulating cholesterol to promote cell growth. Consequently, cholesterol-lowering drugs such as statins are being evaluated in prostate cancer treatment. Furthermore, natural products such as betulin (from birch tree bark) and tocotrienol (a minor form of vitamin E) have been shown to lower cholesterol levels. Using these drugs and oxysterols, we have determined which aspects of cholesterol homoeostasis should be targeted in prostate cancer, e.g. cellular cholesterol levels are increased by the transcription factor SREBP-2 (sterol-regulatory-element-binding protein isoform 2), whereas LXR (liver X receptor) promotes cholesterol efflux. Whereas betulin exerted non-specific effects on cell viability, tocotrienols produced a strong direct correlation between SREBP-2 activity and cell viability. Mechanistically, tocotrienols lowered SREBP-2 activity by degrading mature SREBP-2 independently of the proteasome. In contrast, no correlation was seen between LXR activity and cell viability, implying that SREBP-2 is a better target than LXR for prostate cancer treatment. Lastly, androgen-dependent and -independent LNCaP cells were both sensitive to tocotrienols. Overall, this suggests that tocotrienols and other drugs targeting the SREBP-2 pathway are a potential therapeutic option for prostate cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Cell Survival; CHO Cells; Cholesterol; Chromans; Cricetinae; Cricetulus; Humans; Intracellular Signaling Peptides and Proteins; Liver X Receptors; Male; Membrane Proteins; Mutant Proteins; Neoplasm Proteins; Orphan Nuclear Receptors; Prostatic Neoplasms; Recombinant Proteins; Sterol Regulatory Element Binding Protein 2; Tocotrienols; Triterpenes; Vitamin E

Anti-inflammatory actions of the vitamin E fragment tocotrienol have not been described for microglia. Here, we screened palm α-, γ- and δ-tocotrienol isoforms and Tocomin® 50% (contains spectrum of tocotrienols and tocopherols) for their ability to limit nitric oxide (NO) production by BV2 microglia. Microglia were treated with varying doses of tocotrienols for 24h and stimulated with 1 μg/ml lipopolysaccharide (LPS). All tocotrienol isoforms reduced NO release by LPS-stimulated microglia, with 50 μM being the most potent tocotrienol dose. Of the isoforms tested, δ-tocotrienol lowered NO levels the most, reducing NO by approximately 50% at 48 h post-LPS treatment (p<.05). None of the tocotrienol doses tested affected microglia viability.

Topics: Animals; Antioxidants; Cell Line; Cell Survival; Chromans; Lipopolysaccharides; Mice; Microglia; Nitric Oxide; Palm Oil; Plant Oils; Tocotrienols; Vitamin E

Vitamin E homologues, specifically tocotrienols, have been shown to have favorable effects on bone. They possess properties that are indicative of anti-resorptive activity, suggesting the potential for vitamin E in preventing bone loss. To investigate the anti-resorptive activity of the various vitamin E homologues, we cultured human osteoclasts from blood-derived CD14+ cells on collagen, dentin, and calcium phosphate substrates, with some samples supplemented with vitamin E homologues in their cell culture medium. These were compared to the clinically used bisphosphonate, pamidronate. Compounds were either added at the start of culture to study effects on osteoclast formation, or at the start of osteoclastic resorption to determine their effects on activity. The alpha- and gamma-tocotrienol isomers inhibited osteoclast formation without consequent reduction in total cell number. Only gamma-tocotrienol inhibited osteoclast activity without toxicity. Gamma-tocotrienol was the most potent inhibitor of both osteoclast formation and activity and requires further investigation into its anti-resorptive effects on bone.

Topics: Antioxidants; Bone Resorption; Cell Proliferation; Cells, Cultured; Chromans; Dose-Response Relationship, Drug; Humans; Lipopolysaccharide Receptors; Osteoclasts; Osteogenesis; Vitamin E

Palm oil is enriched in vitamin E in the form of alpha-, gamma-, and delta-tocotrienols. Dietary tocotrienol supplements have been shown to prevent atherosclerosis development in patients and preclinical animal models. However, the mechanistic basis for this health beneficial effect is not well established. Peroxisome proliferator-activated receptors alpha, gamma, and delta (PPARalpha, PPARgamma, and PPARdelta) are ligand regulated transcription factors that play essential preventive roles in the development of atherosclerosis through regulating energy metabolism and inflammation. In this study, we presented data that the tocotrienol rich fraction (TRF) of palm oil activated PPARalpha, PPARgamma, and PPARdelta in reporter based assays. Importantly, TRF attenuated the development of atherosclerosis in ApoE-/- mice through inducing PPAR target gene liver X receptor alpha (LXRalpha) and its down-stream target genes apolipoproteins and cholesterol transporters, suggesting that modulating the activities of PPARs is a key aspect of the in vivo action of tocotrienols.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Chromans; Humans; Liver X Receptors; Male; Mice; Orphan Nuclear Receptors; Palm Oil; Peroxisome Proliferator-Activated Receptors; Plant Oils; PPAR alpha; Tocotrienols; Tumor Cells, Cultured; Vitamin E

Breast cancer is the most common malignancy among women, with an age-specific incidence profile. During the last years much evidence has accumulated demonstrating the anticancer activity of tocotrienols (T3), a subfamily of natural vitamin E (VE). In this study, mouse and human breast cancer cells (with or without HER-2/neu oncogene overexpression) were used to investigate the anticancer effect of alpha-, gamma-, and delta-tocotrienols in comparison with alpha-tocopheryl succinate (alpha-TOS), a synthetic derivative with widely recognized anticancer properties.. Human and mouse breast cancer cell lines were used. The effect of VE compounds on cell viability was investigated using Alamar Blue assay. Apoptosis was assessed by propidium iodide and JC-1 staining. Expression of senescence-associated markers was evaluated by RT-PCR and Western blot analysis was used to examine the changes in the expression levels of HER-2/neu.. gamma- and delta-Tau3 reduced cell viability with IC(50) values of less than half those of alpha-T3 and alpha-TOS. gamma- and delta-Tau3, and alpha-TOS to a lesser extent, induced apoptosis possibly via the mitochondrial pathway, and the expression of senescent-like growth arrest markers as p53, p21, and p16. Both alpha-TOS and tocotrienols downregulated HER-2/neu in tumor cells overexpressing this oncogene, but this effect did not seem to be essential for the antitumor activity of these compounds.. We demonstrate that in HER-2/neu breast cancer cells, the non-alpha form of T3 shows stronger anticancer activity than the synthetic VE-derivative alpha-TOS and this effect occurs independently from the inhibition of HER-2/neu oncogene expression.

Topics: alpha-Tocopherol; Animals; Antineoplastic Agents; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Chromans; Drug Screening Assays, Antitumor; Female; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; Mice; Receptor, ErbB-2; Tocotrienols; Vitamin E

Topics: Animals; Cell Line; Chromans; Enzyme Activation; Humans; Melanins; Mice; Mice, Nude; Monophenol Monooxygenase; Skin; Ultraviolet Rays; Vitamin E; Xenograft Model Antitumor Assays

Present study aimed to elucidate the suppression of serum lipids by gamma- and delta-tocotrienol (γδT3).. The lipid-lowering effects of γδT3 were investigated using HepG2 liver cell line, hypercholesterolemic mice and borderline-high cholesterol patients.. In-vitro results demonstrated two modes of action. First, γδT3 suppressed the upstream regulators of lipid homeostasis genes (DGAT2, APOB100, SREBP1/2 and HMGCR) leading to the suppression of triglycerides, cholesterol and VLDL biosyntheses. Second, γδT3 enhanced LDL efflux through induction of LDL receptor (LDLr) expression. Treatment of LDLr-deficient mice with 1 mg/day (50 mg/kg/day) γδT3 for one-month showed 28%, 19% reduction in cholesterol and triglyceride levels respectively, whereas HDL level was unaltered. The lipid-lowering effects were not affected by alpha-tocopherol (αTP). In a placebo-controlled human trial using 120 mg/day γδT3, only serum triglycerides were lowered by 28% followed by concomitant reduction in the triglyceride-rich VLDL and chylomicrons. In contrast, total cholesterol, LDL and HDL remained unchanged in treated and placebo groups. The discrepancies between in-vitro, in-vivo and human studies may be attributed to the differential rates of post-absorptive γδT3 degradation and LDL metabolism.. Reduction in triglycerides synthesis and transport may be the primary benefit caused by ingesting γδT3 in human.

Topics: Animals; Apolipoprotein B-100; Blotting, Western; Carcinoma, Hepatocellular; Cell Proliferation; Cells, Cultured; Chromans; Diacylglycerol O-Acyltransferase; Female; Humans; Hydroxymethylglutaryl CoA Reductases; Lipoproteins, VLDL; Liver; Liver Neoplasms; Male; Mice; Mice, Knockout; Receptors, LDL; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sterol Regulatory Element Binding Protein 1; Sterol Regulatory Element Binding Protein 2; Triglycerides; Vitamin E

In contrast to extensive studies on tocopherols, very little is understood about tocotrienols (T3). We evaluated the antitumor activities of gamma-T3 and delta-T3 in murine hepatoma MH134 cells in vitro and in vivo. We found that delta-T3 inhibited the growth of MH134 cells more strongly than gamma-T3 by inducing apoptosis. In C3H/HeN mice implanted with MH134, it was found that gamma-T3 and delta-T3 feeding significantly delayed tumor growth. On the other hand, both T3 had no significant effect on body weight, normal-tissue weight and immunoglobulin levels. Intriguingly, we found that T3 was detected in tumor, but not in normal tissues. These results, to our knowledge, are the first demonstration of specific accumulation of gamma-T3 and delta-T3 in tumors and suggest that T3 accumulation is critical for the antitumor activities of T3.

Topics: Adipose Tissue; alpha-Tocopherol; Animals; Antibodies; Antineoplastic Agents; Antioxidants; Apoptosis; Body Weight; Cell Line, Tumor; Cell Proliferation; Chromans; Liver; Liver Neoplasms, Experimental; Lung; Lymphocytes; Male; Mice; Mice, Inbred C3H; Organ Size; Spleen; Tumor Burden; Vitamin E

With use of inexpensive commercially available raw materials, chromanmethanol precursors to the natural beta-, gamma-, and delta-tocotrienols have been prepared in high yield. Enzymatic resolution afforded chiral chromanmethanols in high enantiomeric excess. Subsequent attachment of the farnesyl side chain was high yielding, thus allowing the preparation of asymmetric beta-, gamma-, and delta-tocotrienols in one final step wherein simultaneous deprotection of the phenol and removal of the sulfone group occurs. This chemistry provides the first synthesis of natural-series beta-tocotrienol.

Topics: Chromans; Methanol; Methylation; Molecular Structure; Stereoisomerism; Vitamin E

We evaluated the antitumor activity of tocotrienol (T3) on human hepatoma Hep3B cells. At first, we examined the effect of T3 on the proliferation of human hepatoma Hep3B cells and found that gamma-T3 inhibited cell proliferation at lower concentrations and shorter treatment times than alpha-T3. Then, we examined the effect of gamma-T3 apoptosis induction and found that gamma-T3 induced poly (ADP-ribose) polymerase (PARP) cleavage and stimulated a rise in caspase-3 activity. In addition, gamma-T3 stimulated a rise in caspase-8 and caspase-9 activities. We also found that gamma-T3-induced apoptotic cell death was accompanied by up-regulation of Bax and a rise in the fragments of Bid and caspase-8. These data indicate that gamma-T3 induced apoptosis in Hep3B cells and that caspase-8 and caspase-9 were involved in apoptosis induction. Moreover, these results suggest that Bax and Bid regulated apoptosis induction by gamma-T3.

Topics: Apoptosis; Carcinoma, Hepatocellular; Caspase 3; Caspase 8; Caspase 9; Caspases; Cell Division; Cell Line, Tumor; Chromans; Gene Expression; Genes, bcl-2; Humans; Liver Neoplasms; Poly(ADP-ribose) Polymerases; Tocotrienols; Vitamin E

Sterol-regulated ubiquitination marks 3-hydroxy-3-methylglutaryl coenzyme A reductase, a rate-determining enzyme in cholesterol synthesis, for endoplasmic reticulum (ER)-associated degradation by 26 S proteasomes. This degradation, which results from sterol-induced binding of reductase to ER membrane proteins called Insigs, contributes to the complex, multivalent feedback regulation of the enzyme. Degradation of HMG-CoA reductase is also stimulated by various forms of vitamin E, a generic term for alpha-, beta-, delta-, and gamma-tocopherols and tocotrienols, which are primarily recognized for their potent antioxidant activity. Here, we show that delta-tocotrienol stimulates ubiquitination and degradation of reductase and blocks processing of sterol regulatory element-binding proteins (SREBPs), another sterol-mediated action of Insigs. The gamma-tocotrienol analog is more selective in enhancing reductase ubiquitination and degradation than blocking SREBP processing. Other forms of vitamin E neither accelerate reductase degradation nor block SREBP processing. In vitro assays indicate that gamma- and delta-tocotrienol trigger reductase ubiquitination directly and do not require further metabolism for activity. Taken together, these results provide a biochemical mechanism for the hypocholesterolemic effects of vitamin E that have been observed in animals and humans.

Topics: Cell Line; Chromans; Endoplasmic Reticulum; Feedback, Physiological; Fibroblasts; Humans; Hydroxymethylglutaryl-CoA-Reductases, NADP-dependent; Hypercholesterolemia; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Proteasome Endopeptidase Complex; Sterols; Ubiquitin; Vitamin E

A single dose comparative bioavailability study was conducted to evaluate the bioavailability of tocotrienols from two self-emulsifying formulations, one of which produced an emulsion that readily lipolysed under in vitro condition (SES-A), while the other produced a finer dispersion with negligible lipolysis (SES-B) in comparison with that of a non-self-emulsifying formulation in soya oil. The study was conducted according to a three-way crossover design using six healthy human volunteers. Statistically significant differences were observed between the logarithmic transformed peak plasma concentration (Cmax) and total area under the plasma concentration-time curve (AUC(0-infinity)) values of both SES-A and -B compared to NSES-C indicating that SES-A and -B achieved a higher extent of absorption compared to NSES-C. Moreover, the 90% confidence interval of the AUC(0-infinity) values of both SES-A and -B over those of NSES-C were between 2-3 suggesting an increase in bioavailability of about two-three times compared to NSES-C. Both SES-A and -B also achieved a faster onset of absorption. However, both SES-A and -B had comparable bioavailability, despite the fact that SES-B was able to form emulsions with smaller droplet size. Thus, it appeared that both droplet sizes as well as the rate and extent of lipolysis of the emulsion products formed were important for enhancing the bioavailability of the tocotrienols from the self-emulsifying systems.

Topics: Administration, Oral; Adult; Area Under Curve; Biological Availability; Chemistry, Pharmaceutical; Chromans; Chromatography, High Pressure Liquid; Cross-Over Studies; Emulsions; Glycerides; Half-Life; Humans; Lipolysis; Male; Organic Chemicals; Particle Size; Polysorbates; Soybean Oil; Tocotrienols; Vitamin E

A study was conducted to evaluate the bioavailability of alpha-, gamma- and delta-tocotrienols administered via oral, intravenous, intramuscular and intraperitoneal routes in rats. Three separate experiments, each conducted according to a two-way crossover design, were carried out to compare intravenous and oral, intramuscular and oral, and intraperitoneal and oral administration. Oral absorption of all three tocotrienols was found to be incomplete. Of the three tocotrienols, alpha-tocotrienol had the highest oral bioavailability, at about 27.7+/-9.2%, compared with gamma- and delta-tocotrienols, which had values of 9.1+/-2.4% and 8.5+/-3.5%, respectively. Such biodiscrimination was also observed in their total clearance rates (estimated from the intravenous data). alpha-Tocotrienol showed the lowest clearance rate at about 0.16 L kg(-1) h(-1), whereas that of delta- and gamma-tocotrienols was quite similar, with values of 0.24 and 0.23 L kg(-1) h(-1), respectively. Interestingly, all three tocotrienols were found to be negligibly absorbed when administered intraperitoneally and intramuscularly. Thus, these two routes of administration should be avoided when evaluating the biological activities of the tocotrienols in whole animal experiments.

Topics: Administration, Oral; Animals; Biological Availability; Chromans; Cross-Over Studies; Infusions, Intravenous; Infusions, Parenteral; Injections, Intramuscular; Male; Rats; Rats, Sprague-Dawley; Tissue Distribution; Tocotrienols; Vitamin E

Tocotrienols are added as antioxidants to food. As there have been no reports of toxicological evaluation, a 13-week oral toxicity study was performed in Fischer 344 rats of both sexes at dose levels of 0 (group 1), 0.19 (group 2), 0.75 (group 3) and 3% (group 4) of a preparation in powdered diet. Suppression of body weight gain was observed in group 4 males. On hematological examination, significant decrease in mean corpuscular volume (MCV) was observed in all treated males. Platelets were significantly reduced in group 3 and 4 males. Hemoglobin concentration, MCV, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were significantly decreased in group 3 and 4 females and hematocrit in group 4 females. On serum biochemical examination, increase in the albumin/globulin ratio (A/G) and alkaline phosphatase in all treated males, elevated alanine transaminase in group 4 of both sexes and increases in asparagine transaminase and gamma-glutamyl transaminase in group 4 females were observed. With regard to relative organ weights, liver weights in group 4 of both sexes and adrenal weights in all treated males demonstrated an increase, and ovary and uterus weights in group 4 females were reduced. Histopathologically, slight hepatocellular hypertrophy in group 3 and 4 males, and reduction of cytoplasmic vacuolation in the adrenal cortical region in group 4 males were observed. Because of pathological changes in male liver and hematological changes in females, the no-observed-adverse-effect level (NOAEL) was concluded to be 0.19% in the diet (120 mg/kg body weight/day for male rats and 130 mg/kg body weight/day for female rats). As a decrease in MCV, an increase in the A/G, elevation of alkaline phosphatase and increase in adrenal weight were observed in all treated males, a no-observed-effect level (NOEL) could not be determined in this examination.

Topics: Administration, Oral; Adrenal Glands; Animals; Blood Cell Count; Chromans; Dose-Response Relationship, Drug; Female; Food Additives; Genitalia; Kidney; Liver; Male; No-Observed-Adverse-Effect Level; Rats; Rats, Inbred F344; Sex Factors; Tocotrienols; Vitamin E

Tocopherols and tocotrienols represent the two subclasses within the vitamin E family of compounds. However, tocotrienols are significantly more potent than tocopherols in suppressing epidermal growth factor (EGF)-dependent normal mammary epithelial cell growth. EGF is a potent mitogen for normal mammary epithelial cells and an initial event in EGF-receptor mitogenic-signalling is protein kinase C (PKC) activation. Studies were conducted to determine if the antiproliferative effects of specific tocopherol and tocotrienol isoforms are associated with a reduction in EGF-receptor mitogenic signalling and/or PKC activation. Normal mammary epithelial cells isolated from midpregnant BALB/c mice were grown in primary culture, and maintained on serum-free media containing 10 ng/mL EGF as a mitogen, and treated with various doses (0-250 microm) of alpha-, gamma-, or delta-tocopherol or alpha-, gamma-, or delta-tocotrienol. Treatment with growth inhibitory doses of delta-tocopherol (100 microm), alpha-tocotrienol (50 microm), or gamma- or delta-tocotrienol (10 microm) did not affect EGF-receptor levels, EGF-induced EGF-receptor tyrosine kinase activity, or total intracellular levels of PKC(alpha). However, these treatments were found to inhibit EGF-induced PKC(alpha) activation as determined by its translocation from the cytosolic to membrane fraction. Treatment with 250 microm alpha- or gamma-tocopherol had no affect on EGF-receptor mitogenic signalling or cell growth. These findings demonstrate that the inhibitory effects of specific tocopherol and tocotrienol isoforms on EGF-dependent normal mammary epithelial cell mitogenesis occurs downstream from the EGF-receptor and appears to be mediated, at least in part, by a reduction in PKC(alpha) activation.

Topics: alpha-Tocopherol; Animals; Blotting, Western; Cell Division; Cells, Cultured; Chromans; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Epidermal Growth Factor; Epithelial Cells; Female; gamma-Tocopherol; Mice; Mice, Inbred BALB C; Pregnancy; Protein Kinase C; Time Factors; Tocotrienols; Vitamin E

Studies were conducted to determine the comparative effects of tocopherols and tocotrienols on normal mammary epithelial cell growth and viability. Cells isolated from midpregnant BALB/c mice were grown within collagen gels and maintained on serum-free media. Treatment with 0-120 microM alpha- and gamma-tocopherol had no effect, whereas 12.5-100m microM tocotrienol-rich fraction of palm oil (TRF), 100-120 microM delta-tocopherol, 50-60 microM alpha-tocotrienol, and 8-14 microM gamma- or delta-tocotrienol significantly inhibited cell growth in a dose-responsive manner. In acute studies, 24-h exposure to 0-250 microM alpha-, gamma-, and delta-tocopherol had no effect, whereas similar treatment with 100-250 microM TRF, 140-250 microM alpha-, 25-100 microM gamma- or delta-tocotrienol significantly reduced cell viability. Growth-inhibitory doses of TRF, delta-tocopherol, and alpha-, gamma-, and delta-tocotrienol were shown to induce apoptosis in these cells, as indicated by DNA fragmentation. Results also showed that mammary epithelial cells more easily or preferentially took up tocotrienols as compared to tocopherols, suggesting that at least part of the reason tocotrienols display greater biopotency than tocopherols is because of greater cellular accumulation. In summary, these findings suggest that the highly biopotent gamma- and delta-tocotrienol isoforms may play a physiological role in modulating normal mammary gland growth, function, and remodeling.

Topics: Animals; Apoptosis; Cell Division; Cells, Cultured; Chromans; DNA Fragmentation; Dose-Response Relationship, Drug; Epidermal Growth Factor; Epithelial Cells; Female; Inhibitory Concentration 50; Isomerism; Mammary Glands, Animal; Mice; Mice, Inbred BALB C; Palm Oil; Plant Oils; Tocotrienols; Vitamin E

To assess the efficiency of tocotrienols against oxidative damage, we have demonstrated in a model-system nematode, Caenorhabditis elegans, that tocotrienol administration reduced the accumulation of protein carbonyl (a good indicator of oxidative damage during aging) and consequently extended the mean life span (LS), but not the maximum LS. Conversely, alpha-tocopherol acetate did not affect these parameters. As a way to evaluate the protective ability of tocotrienols against oxidative stress, the life spans of animals administrated tocotrienols before or after exposure to ultraviolet B-induced oxidative stress were measured. Ultraviolet B irradiation shortened the mean LS of animals, whereas preadministration of tocotrienols recovered the mean LS to that of unirradiated animals. Interestingly, postadministration also extended the mean LS more than that of unirradiated animals, and administration through the LS conferred greater protection. Thus, the administration of tocotrienols to animals results in a reduction of oxidative stress risks. These data indicated that tocotrienols merit further investigation as possible agents for antiaging and oxidative stress prevention. In addition, they suggest that C. elegans will continue to provide provocative clues into the mechanisms of aging.

Topics: Animals; Antioxidants; Caenorhabditis elegans; Chromans; Longevity; Proteins; Tocotrienols; Vitamin E

We evaluated the effects of vitamin E and beta-carotene on apolipoprotein (apo)E +/- female mice, which develop atherosclerosis only when fed diets high in triglyceride and cholesterol. Mice were fed a nonpurified control diet (5.3 g/100 g triglyceride, 0.2 g/100 g cholesterol), an atherogenic diet alone (15.8 g/100 g triglyceride, 1.25 g/100 g cholesterol, 0.5 g/100 g Na cholate) or the atherogenic diet supplemented with either 0.5 g/100 g (+)-alpha-tocopherol (mixed isomers); 0.5 g/100 g palm tocopherols (palm-E; 33% alpha-tocopherol, 16.1% alpha-tocotrienol, 2.3% beta-tocotrienol, 32.2% gamma-tocotrienol, 16.1% delta-tocotrienol); 1.5 g/100 g palm-E; or 0.01 g/100 g palm-carotenoids (58% beta-carotene, 33% alpha-carotene, 9% other carotenoids). Compared with mice fed the control diet, plasma cholesterol was fourfold greater in mice fed the atherogenic diet. Mice fed the 1.5 g/100 g palm-E supplement had 60% lower plasma cholesterol than groups fed the other atherogenic diets. Mice fed the atherogenic diet had markedly higher VLDL, intermediate density lipoprotein (IDL) and LDL cholesterol and markedly lower HDL cholesterol than the controls. Lipoprotein patterns in mice supplemented with alpha-tocopherol or palm carotenoids were similar to those of the mice fed the atherogenic diet alone, but the pattern in mice supplemented with 1. 5 g/100 g palm-E was similar to that of mice fed the control diet. In mice fed the atherogenic diet, the hepatic cholesterol plus cholesterol ester concentration was 4.4-fold greater than in mice fed the control diet. Supplementing with 1.5 g/100 g palm-E lowered hepatic cholesterol plus cholesterol ester concentration 66% compared with the atherogenic diet alone. Mice fed the atherogenic diet had large atherosclerotic lesions at the level of the aortic valve. With supplements of 0.5 g/100 g palm-E or 1.5 g/100 g palm-E, the size of the lesions was 92 or 98% smaller, respectively. The 0.5 g/100 g alpha-tocopherol and palm carotenoid supplements had no effect. Supplements did not alter mRNA abundance for apolipoproteins A1, E, and C3. The beneficial effect of tocotrienols on atherogenesis, the plasma lipoprotein profile and accumulation of hepatic cholesterol esters cannot be attributed to their antioxidant properties.

Topics: Animals; Apolipoproteins E; Arteriosclerosis; Cholesterol; Cholesterol, Dietary; Chromans; Chromatography, High Pressure Liquid; Dietary Fats; Female; Lipid Metabolism; Lipoproteins; Liver; Male; Mice; Mice, Inbred C57BL; Tocotrienols; Triglycerides; Vitamin E

The apoptosis-inducing properties of RRR-alpha-, beta-, gamma-, and delta-tocopherols, alpha-, gamma-, and delta-tocotrienols, RRR-alpha-tocopheryl acetate (vitamin E acetate), and RRR-alpha-tocopheryl succinate (vitamin E succinate) were investigated in estrogen-responsive MCF7 and estrogen-nonresponsive MDA-MB-435 human breast cancer cell lines in culture. Apoptosis was characterized by two criteria: 1) morphology of 4,6-diamidino-2-phenylindole-stained cells and oligonucleosomal DNA laddering. Vitamin E succinate, a known inducer of apoptosis in several cell lines, including human breast cancer cells, served as a positive control. The estrogen-responsive MCF7 cells were more susceptible than the estrogen-nonresponsive MDA-MB-435 cells, with concentrations for half-maximal response for tocotrienols (alpha, gamma, and delta) and RRR-delta-tocopherol of 14, 15, 7, and 97 micrograms/ml, respectively. The tocotrienols (alpha, gamma, and delta) and RRR-delta-tocopherol induced MDA-MB-435 cells to undergo apoptosis, with concentrations for half-maximal response of 176, 28, 13, and 145 micrograms/ml, respectively. With the exception of RRR-delta-tocopherol, the tocopherols (alpha, beta, and gamma) and the acetate derivative of RRR-alpha-tocopherol (RRR-alpha-tocopheryl acetate) were ineffective in induction of apoptosis in both cell lines when tested within the range of their solubility, i.e., 10-200 micrograms/ml. In summary, these studies demonstrate that naturally occurring tocotrienols and RRR-delta-tocopherol are effective apoptotic inducers for human breast cancer cells.

Topics: Antioxidants; Apoptosis; Breast Neoplasms; Chromans; Chromatin; DNA, Neoplasm; Female; Humans; Neoplasms, Hormone-Dependent; Tocotrienols; Tumor Cells, Cultured; Vitamin E

Tocopherols and tocotrienols are being increasingly recognized to have an important role in the prevention of atherosclerosis. It has been reported that they protect low-density lipoprotein (LDL) and tissues from oxidative stress and that tocotrienols can reduce plasma cholesterol levels. Two isocratic high-performance liquid chromatography (HPLC) methods for simultaneous analysis of tocopherols, tocotrienols, and cholesterol in muscle tissue were developed. Method A involves basic saponification of the sample, but causes losses of the gamma- and delta-homologs of vitamin E. Method B does not involve saponification, thereby protecting the more sensitive homologs. Both permit rapid analysis of multiple samples and neither requires specialized equipment. These methods may provide techniques useful in simultaneous assessment of oxidative stress status (OSS) and cholesterol levels.

Topics: Animals; Antioxidants; Cattle; Cholesterol; Chromans; Chromatography, High Pressure Liquid; Muscles; Saponins; Sensitivity and Specificity; Tocotrienols; Vitamin E

Tocotrienols are a form of vitamin E, having an unsaturated isoprenoid side-chain rather than the saturated side-chain of tocopherols. The tocotrienol-rich fraction (TRF) from palm oil contains alpha-tocopherol and a mixture of alpha-, gamma- and delta-tocotrienols. Earlier studies have shown that tocotrienols display anticancer activity. We previously reported that TRF, alpha-, gamma- and delta-tocotrienols inhibited proliferation of estrogen receptor-negative MDA-MB-435 human breast cancer cells with 50% inhibitory concentrations (IC50) of 180, 90, 30 and 90 microg/mL, respectively, whereas alpha-tocopherol had no effect at concentrations up to 500 microg/mL. Further experiments with estrogen receptor-positive MCF-7 cells showed that tocotrienols also inhibited their proliferation, as measured by [3H] thymidine incorporation. The IC50s for TRF, alpha-tocopherol, alpha-, gamma- and delta-tocotrienols were 4, 125, 6, 2 and 2 microg/mL, respectively. Tamoxifen, a widely used synthetic antiestrogen inhibits the growth of MCF-7 cells with an IC50 of 0.04 microg/mL. We tested 1:1 combinations of TRF, alpha-tocopherol and the individual tocotrienols with tamoxifen in both cell lines. In the MDA-MB-435 cells, all of the combinations were found to be synergistic. In the MCF-7 cells, only 1:1 combinations of gamma- or delta-tocotrienol with tamoxifen showed a synergistic inhibitory effect on the proliferative rate and growth of the cells. The inhibition by tocotrienols was not overcome by addition of excess estradiol to the medium. These results suggest that tocotrienols are effective inhibitors of both estrogen receptor-negative and -positive cells and that combinations with tamoxifen should be considered as a possible improvement in breast cancer therapy.

Topics: Antineoplastic Agents, Hormonal; Antioxidants; Breast Neoplasms; Cell Division; Cell Survival; Chromans; Dietary Fats, Unsaturated; Drug Interactions; Estrogen Antagonists; Female; Humans; Palm Oil; Plant Oils; Receptors, Estrogen; Tamoxifen; Tocotrienols; Tumor Cells, Cultured; Vitamin E

Tocotrienols from palm oil showed significant ability to inhibit oxidative damage induced by ascorbate-Fe2+ and photosensitization, involving different mechanisms, in rat liver microsomes. The tocotrienol-rich fraction from palm oil (TRF), being tried as a more economical and efficient substitute for alpha-tocopherol, showed time- and concentration-dependent inhibition of protein oxidation as well as lipid peroxidation. It was more effective against protein oxidation. The extent of inhibition by TRF varied with different peroxidation products such as conjugated dienes, lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS). Among the constituents of TRF, gamma-tocotrienol was the most effective followed by its alpha- and delta-isomers. In general, at a low concentration of 5 microM, TRF was able to prevent oxidative damage to significant extent (37% inhibition of protein oxidation and 27-30% of lipid peroxidation at 1 h of incubation). The protective ability of TRF (30.1% at 5 microM with TBARS formation) was significantly higher than that of the dominant form of vitamin E, alpha-tocopherol (16.5% under same conditions). Hence our studies indicate that this fraction from palm oil can be considered as an effective natural antioxidant supplement capable of protecting cellular membranes against oxidative damage.

Topics: Animals; Antioxidants; Chromans; Female; Kinetics; Lipid Peroxidation; Microsomes, Liver; Oxidation-Reduction; Palm Oil; Plant Oils; Proteins; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances; Tocotrienols; Vitamin E

Lymphatic transport of alpha-, gamma- and delta-tocotrienols and alpha-tocopherol was measured in thoracic duct-cannulated rats. Animals were administered 3 ml of a test emulsion containing 200 mg sodium taurocholate, 50 mg fatty acid free-albumin, 200 mg fat and 100 mg of a mixture of tocotrienols and alpha-tocopherol (Exp. 1) or 10 mg of purified alpha-, gamma- or delta-tocotrienol or alpha-tocopherol (Exp. 2) through a gastric tube. Quantitative lymphatic recovery of oleic acid given as triolein was obtained in these experimental conditions. The 24-hours recovery of tocotrienols and alpha-tocopherol were 10-20% of the administered dose in Exp. 1. The recovery of alpha-tocotrienol was about 2-times higher than that of alpha-tocopherol, while that of gamma- and delta-tocotrienols was intermediate between these two alpha-forms. In Exp. 2, where these compounds were administered individually, the 24 hours recovery ranged from 22 to 37% of the administered dose. Again, the recovery of alpha-tocotrienol was significantly higher than that of the other tocotrienols and alpha-tocopherol, while that of gamma- and delta-tocotrienols and alpha-tocopherol was comparable. Thus, the results show the preferential absorption of alpha-tocotrienol compared to gamma- and delta-tocotrienols and alpha-tocopherol.

Topics: Animals; Biological Transport; Chromans; Emulsions; Intestinal Absorption; Kinetics; Lymphatic System; Male; Oleic Acid; Rats; Rats, Sprague-Dawley; Thoracic Duct; Tocotrienols; Triolein; Vitamin E

Tocotrienols are farnesylated benzopyran natural products that exhibit hypocholesterolemic activity in vitro and in vivo. The mechanism of their hypolipidemic action involves posttranscriptional suppression of HMG-CoA reductase by a process distinct from other known inhibitors of cholesterol biosynthesis. An efficient synthetic route to tocotrienols and their isolation from palm oil distillate using an improved procedure is presented. gamma-Tocotrienol exhibits a 30-fold greater activity toward cholesterol biosynthesis inhibition compared to alpha-tocotrienol in HepG2 cells in vitro. The synthetic (racemic) and natural (chiral) tocotrienols exhibit nearly identical cholesterol biosynthesis inhibition and HMG-CoA reductase suppression properties as demonstrated in vitro and in vivo.

Topics: Animals; Anticholesteremic Agents; Cells, Cultured; Chickens; Cholesterol; Chromans; Humans; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Liver; Male; Rats; Rats, Wistar; Tocotrienols; Vitamin E

The Finns average intake of tocopherols, tocotrienols, and vitamin E (alpha-tocopherol equivalents) was determined. The food consumption data were derived mainly from the national food balance sheets (for 1987). The average Finnish daily diet was composed and analyzed both in spring and in autumn in order to minimize the effect of seasonal variation. The four tocopherols and four tocotrienols were then determined using high-performance liquid chromatography (HPLC). For comparison, the intake of vitamin E compounds was also calculated using the most recent Finnish analytical data on tocopherols and tocotrienols in food. According to the analytical results, the average daily vitamin E intake in Finland was 10.7 mg alpha-tocopherol equivalents (alpha-TE) of which amount 85% is due to alpha-tocopherol. The analyzed values (10.8 mg alpha-TE in spring and 10.7 mg alpha-TE in autumn) of vitamin E intake did not markedly differ from the calculated value (10.3 mg alpha-TE), thus indicating that the Finnish food composition data upon tocopherols and tocotrienols is up-to-date and accurate. The best food sources of vitamin E were dietary fat (41% of the total amount), cereals (18%), and dairy products and eggs (13%). The average Finnish diet contained 9.5 g of polyunsaturated fatty acids (PUFA), which leads to the ratio of 0.9 between alpha-tocopherol (mg) and PUFA (g). According to these results, the dietary recommendations for vitamin E are met in Finland.

Topics: Antioxidants; Chromans; Diet; Eating; Fatty Acids, Unsaturated; Finland; Food Analysis; Humans; Seasons; Tocotrienols; Vitamin E