Antioxidant status following postprandial challenge of two different doses of tocopherols and tocotrienols / 中西医结合学报

OBJECTIVE@#Tocotrienols (T3s) have been hypothesized to have greater antioxidant capacity than tocopherols (Ts) due to differences in biokinetics that affect their absorption and function. The present trial compares the antioxidant effectiveness following postprandial challenge of two different doses of α-T or palm T3-rich fraction (TRF) treatments and evaluates their dose-response effects on antioxidant status.@*METHODS@#Ten healthy volunteers were given four different doses of vitamin E formulations (268 mg α-T, 537 mg α-T, 263 mg TRF or 526 mg TRF) in a cross-over postprandial trial. Blood was sampled at 0, 2, 4, 5, 6 and 8 hours after meal consumption and plasma antioxidant status including total glutathione, superoxide dismutase, malondialdehyde (MDA), ferric reducing antioxidant potential and trolox-equivalent antioxidant capacity, was analyzed.@*RESULTS@#Supplementation with the different doses of either α-T or TRF did not significantly improve overall antioxidant status. There was no significant difference in overall antioxidant status among treatments at the different doses compared. However, a significant dose-response effect was observed for plasma MDA throughout the 8-hour postprandial period. MDA was significantly lower after the 537 mg α-T treatment, compared to the 268 mg α-T treatment; it was also lower after the 526 mg TRF treatment compared to the 263 mg TRF treatment (P < 0.05).@*CONCLUSION@#T3 and α-T demonstrated similar antioxidant capacity, despite markedly lower levels of T3 in blood and lipoproteins, compared to α-T.

Inhibitory effects of γ-tocotrienol on invasion and migration of human gastric cancer SGC-7901 cells and its mechanism / 肿瘤

Objective: To investigate the effects of γ-tocotrienol (γ-T3) on the invasion and migration of human gastric cancer SGC-7901 cells as well as its possible molecular mechanism. Methods: The different concentrations (0, 15, 30, 45, 60, and 100 μmol/L) of γ-T3 were used to treat SGC-7901 cells. Then the proliferation, migration and invasion of SGC-7901 cells were detected by CCK-8 assay, cell scratch wound healing assay and Transwell invasion assay, respectively. Furthermore, the expressions of cyclooxygenase-2 (COX-2) and nuclear factor-kappa B (NF- κB) signal pathway proteins were detected by Western blotting. Results: After treatment with different concentrations (15-100 μmol/L ) of γ-T3 for 24, 48 and 72 h, the proliferation of SGC-7901cells was evidently inhibited in a time- and dose-dependent manner (all P<0.01). After treatment with γ-T3 (15-60 μmol/L) alone or combined with tumor necrosis factor-alpha (TNF-α) (10 ng/mL) for 24 h, the migration and invasion abilities of SGC-7901 cells were significantly inhibited (all P<0.01). The expressions of NF-κB, NF-κB p65 and COX-2 proteins were significantly down-regulated in SGC-7901 cells after γ-T3 (15-60 μmol/L) treatment for 24 h (all P<0.01). Conclusion: γ-T3 can inhibit the invasion and migration of human gastric cancer SGC-7901 cells. Its mechanism may be associated with blocking NF-κB signal pathway and reducing the expression of COX-2 protein.

Liposoluble vitamins in Crustacean feed: Metabolic and Histological responses.

Vitamins are vital for normal growth and survival of living organisms and they are distributed in feedstuffs in small quantities. This review is focused on the liposoluble vitamins (A, D, E and K) in the diets and metabolic responses of the Argentine penaeoid shrimps Pleoticus muelleri and Artemesia longinaris, distributed along the South American coast line. Growth, survival and histological analyses serve as indicators of the nutritional value derived from vitamin deficiency. Liposoluble vitamins are also related to stress, antioxidant defense and immune response of shrimps. Effective diet for shrimp culture that provide not only macronutrients including protein and lipid but also micronutrients such as vitamins for optimal growth is an ever improving subject. This review may help formulating suitable feeds for shrimps.

Palm Tocotrienols Reduce Lipopolysaccharide-Stimulated Inflammatory Responses of Microglia

Introduction: The potential immunoregulatory effects of tocotrienols, the less studied form of vitamin E, had not been determined for microglia until our last publication showcased primary evidence of palm tocotrienols limiting microglia activation, explicitly by inhibiting nitric oxide (NO) production. Here we further explored the nitrite scavenging activity of the two most potent NO-reducing tocotrienol isoforms - δ- tocotrienol and Tocomin50% (contains a spectrum of tocotrienols and α-tocopherol) based on their inhibitory effects on NO production and also their effects on CD40 (a microglial co-stimulator molecule) expression of BV2 microglia. Methods: BV2 cells were treated with two different doses of tocotrienols (δ-tocotrienol: 3.96 μg/mL and 19.80 μg/mL; Tocomin50%: 47.50 μg/mL and 237.50 μg/mL) followed by stimulation with 1 μg/mL of lipopolysaccharide (LPS). A chemical scavenging assay was conducted to study the nitrite scavenging activity of δ- tocotrienol. Together with Tocomin50%, we also determined their effects on CD40 expression of BV2 microglia via flow cytometry. Results: We demonstrate that the inhibitory effect of tocotrienols on NO production by microglia is not attributed to their nitrite scavenging activity. Additionally, tocotrienols also reduced the expression of the microglial co-stimulator molecule, CD40. Conclusions: Our data aids the further characterisation of the actions of tocotrienols on microglia, offering insight into the potential modulatory properties of palm tocotrienols on microglial inflammatory responses within the central nervous system (CNS).

Potential of Mixed Tocotrienol Supplementation to Reduce Cholesterol and Cytokines Level in Adults with Metabolic Syndrome

Introduction: Metabolic syndrome is associated with low-grade, chronic inflammation. Our study aimed to evaluate the effects of tocotrienols supplementation on cytokines and lipid profile in adults with metabolic syndrome. Method: In a 16-week randomised, double-blind, placebo-controlled trial, 70 adults with metabolic syndrome aged 20-60 years were randomly assigned to a mixed tocotrienols group (n=35) that received 400mg/day of mixed tocotrienols or a placebo group (n=35) that received capsules containing soy bean oil. At baseline, week 8 and week 16, anthropometric, body composition and blood pressure measurements were conducted. At baseline and week 16 only, serum levels of total cholesterol (TC) and high density lipoprotein (HDL)-cholesterol, plasma levels of fasting plasma glucose (FPG), interleukin-6 (IL-6), tumouxr necrosis factor- a (TNF-a), leptin, adiponectin and high sensitivity C-reactive protein were also determined. Changes in dietary intake and physical activity level between baseline, week 8 and week 16 were also assessed. Results:In the tocotrienols group, significant reductions from baseline were found in diastolic blood pressure (p=0.001), TC (p=0.008), LDL-cholesterol (p=0.022), HDL-cholesterol (p<0.001), IL-6 (p=0.024) and TNF-a (p=0.013) at week sixteen. However, the changes in the tocotrienols group were not significantly different from those of the placebo group. Conclusion: The 16-week mixed tocotrienols supplementation exerted potential beneficial effects on cytokines and lipid profile in adults with metabolic syndrome. The results might have been confounded by the physiological effects produced by the soy bean oil in the placebo capsule.

Tocotrienols and its impact in cardiovascular health.

Tocotrienols are members of the vitamin E family essential for human nutrition. It has four isomeric forms i.e., α, β, γ, δ. Palm oil and rice bran oil represent two major nutritional sources of natural tocotrienols. Taken orally, tocotrienols are bioavailable to all vital organs. Apart from tocotrienols antioxidant, anti-inflammatory, antineurodegeneration, antimicrobial, anticancer properties it also has antihypercholesterolemic and antiangiogenic properties. During the last 7 years, tocotrienol research has gained substantial momentum. More than 75% of the entire PubMed literature on tocotrienols has been published on or after 2000. This represents major swing in the overall direction of tocotrienol research. The objective of this review is to highlight the potential significance of the tocotrienol in cardiovascular diseases, mainly anti hypercholesterolemic and anti hyperlipidemic properties along with its efficacy and safety.

Tocotrienols: The lesser known form of natural vitamin E.

A recent and growing body of research has shown that members of this vitamin E family posses unique biologic functions. Tocotrienols have garnered much of this recent attention, and in particular a-tocotrienol has been shown to be the most potent neuroprotective form of vitamin E. Protection exclusively mediated through tocotrienols has been arbitrated to many mechanisms including inhibition of 12-LOX, c-Src, PLA2 and through up-regulation of MRP1. Further, tocotrienols have recently been shown to induce arteriogenesis through induction of TIMP1 and decreased activation of MMP2. However, the unique therapeutic potential of tocotrienols is not limited to neuroprotection. Tocotrienols have been shown to have molecular targets including: apoptotic regulators, cytokines, adhesion molecules, enzymes, kinases, receptors, transcription factors, and growth factors. In spite of this large and unique therapeutic potential, scientific literature on tocotrienols only accounts for approximately 1% of vitamin E research. Given the potential of tocotrienols and relatively scant literature, further investigation is warranted.

Study on the action mechanism for δ-tocotrienol-induced apoptosis of human hepatoma HepG2 cells / 肿瘤

Objective:To elucidate action mechanism of δ-tocotrienol in inducing apoptosis of human hepatoma HepG2 cells. Methods:Cell proliferation and viability were assessed by MTT assay; cell cycle distribution, apoptotic rate and mitochondrial membrane potential were measured by using high content screening system; the expression of apoptosis-related protein such as caspase-3, caspase-8, caspase-9, Bcl-2, Bax, tBid and cytochrome C in the HepG2 cells were evaluated by Western blotting. Results:δ-Toco-trienol inhibited HepG2 cell proliferation and induced apoptosis in a dose-dependent manner. This growth-inhibiting effect of δ-toco-trienol correlated with loss of mitochondrial membrane potential and release of cytochrome C from mitochondria to cytoplasm, and regulation of the protein expression of Bcl-2 family members, such as up-regulation of Bax and tBid and down-regulation of Bcl-2. Subsequently tocotrienol induced the activation of caspase-3, caspase-8, and caspase-9 which finally induced apoptosis of hepatoma HepG2 cells. Conclusion:δ-Tocotrienol induced apoptosis of human hepatoma HepG2 cells via mitochondrial pathway and membrane death receptor pathway.

Antitumor effect and mechanisims of tocotrienol / 国际肿瘤学杂志

Tocotrienol has showed inhibition effect on a variety of cancer cells. It has different mecha-nisms in different types of cancer cells. Its anticancer effects may be mediated by anti-proliferation,anti-oxida-tion,pro-apoptotic and affecting apoptosis signal pathway. Further study on tocotrienol will provide scientific the-ory for new antitumor drugs and cancer primary prevention.