γ-Tocotrienol reduces human airway smooth muscle cell proliferation and migration.

Harada T1, Yamasaki A, Chikumi H, Hashimoto K, Okazaki R, Takata M1, Fukushima T, Watanabe M, Kurai J, Halayko AJ, Shimizu E.

Pulm Pharmacol Ther. 2015 May 5. pii: S1094-5539(15)00045-0.

Abstract

AIMS:

Vitamin E is an antioxidant that occurs in 8 different forms (α, β, γ, and δ tocopherol and tocotrienol). Clinical trials of tocopherol supplementation to assess the impact of antioxidant activity in asthma have yielded equivocal results. Tocotrienol exhibits greater antioxidant activity than tocopherol in several biological phenomena in vivo and in vitro. We tested the effect of tocotrienol on human airway smooth muscle (ASM) cell growth and migration, both of which mediate airway remodeling in asthma.

MAIN METHODS:

We measured platelet-derived growth factor-BB (PDGF-BB)-induced ASM cell proliferation and migration by colorimetric and Transwell migration assays in the presence and absence of γ-tocotrienol (an isoform of tocotrienol).

KEY FINDINGS:

PDGF-BB-induced ASM cell proliferation and migration were inhibited by γ-tocotrienol. This effect was associated with inhibition of RhoA activation, but it had no effect on p42/p44 mitogen-activated protein kinase (MAPK) or Akt1 activation. We confirmed that pharmacological inhibition of Rho kinase activity was sufficient to inhibit PDGF-BB-induced ASM cell proliferation and migration.

SIGNIFICANCE:

γ-Tocotrienol could impart therapeutic benefits for airway remodeling in asthma by inhibiting human ASM cell proliferation and migration.

Khor SC, Mohd Yusof YA, Wan Ngah WZ, Makpol S.

Clin Ter. 2015 Mar-Apr;166(2):e81-90.

Abstract

BACKGROUND AND OBJECTIVE:

Vitamin E has been suggested as nutritional intervention for the prevention of degenerative and age-related diseases. In this study, we aimed to elucidate the underlying mechanism of tocotrienol-rich fraction (TRF) in delaying cellular aging by targeting the proliferation signaling pathways in human diploid fibroblasts (HDFs).

MATERIALS AND METHODS:

Tocotrienol-rich fraction was used to treat different stages of cellular aging of primary human diploid fibroblasts viz. young (passage 6), pre-senescent (passage 15) and senescent (passage 30). Several selected targets involved in the downstream of PI3K/AKT and RAF/MEK/ERK pathways were compared in total RNA and protein.

RESULTS:

Different transcriptional profiles were observed in young, pre-senescent and senescent HDFs, in which cellular aging increased AKT, FOXO3, CDKN1A and RSK1 mRNA expression level, but decreased ELK1, FOS and SIRT1 mRNA expression level. With tocotrienol-rich fraction treatment, gene expression of AKT, FOXO3, ERK and RSK1 mRNA was decreased in senescent cells, but not in young cells. The three down-regulated mRNA in cellular aging, ELK1, FOS and SIRT1, were increased with tocotrienol-rich fraction treatment. Expression of FOXO3 and P21Cip1 proteins showed up-regulation in senescent cells but tocotrienol-rich fraction only decreased P21Cip1 protein expression in senescent cells.

CONCLUSIONS:

Tocotrienol-rich fraction exerts gene modulating properties that might be responsible in promoting cell cycle progression during cellular aging.

Chin KY, Ima-Nirwana S.

Drug Des Devel Ther. 2015 Apr 8;9:2049-61.

Abstract

Osteoporosis causes significant health care and economic burden to society, leading to a relentless search for effective preventive agents.Tocotrienol, a member of the vitamin E family, has demonstrated promising potential as an osteoporosis-preventing agent. This review summarizes evidence on the effects of tocotrienol on bone in animal models. Techniques used to examine the effects of tocotrienol on bone in animals included bone histomorphometry, X-ray microtomography, dual-energy X-ray absorptiometry, bone turnover markers, bone calcium content, and biomechanical strength. Tocotrienol was shown to improve osteoblast number, bone formation, mineral deposition, and bone microarchitecture in osteopenic rats. It also decreased osteoclast number and bone erosion in the rats. Tocotrienol supplementation resulted in an improvement in bone mineral density, although biomechanical strength was not significantly altered in the rats. The beneficial effects of tocotrienol on bone can be attributed to its role as an antioxidant, anti-inflammatory agent, suppressor of the mevalonate pathway, and modulator of genes favorable to bone formation.

Abdul Rahman Sazli F, Jubri Z, Abdul Rahman M, Karsani SA, Md Top AG, Wan Ngah WZ.

BMC Complement Altern Med. 2015 Mar 13;15:64

Abstract

BACKGROUND:

To determine the antiproliferative effect of gamma-tocotrienol (GTT) treatment on differential protein expression in HepG2 cells.

METHODS:

HepG2 cells were treated with 70 μM GTT for 48 hours and differentially expressed protein spots were determined by two-dimensional electrophoresis (2DE), identified by MALDI-TOF mass spectrometer (MS) and validated by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS:

GTT treatment on HepG2 cells showed a total of five differentially expressed proteins when compared to their respective untreated cells where three proteins were down-regulated and two proteins were up-regulated. One of these upregulated proteins was identified as peroxiredoxin-4 (Prx4). Validation by qRT-PCR however showed decreased expression of Prx4 mRNA in HepG2 cells following GTT treatment.

CONCLUSIONS:

GTT might directly influence the expression dynamics of peroxiredoxin-4 to control proliferation in liver cancer.

Cicero AF, Rosticci M, Parini A, M M, Urso R, Grandi E, Borghi C.

Nutr J. 2015 Mar 28;14(1):30.

Abstract

BACKGROUND:

Overweight subjects easily develop alterations of the glucose and lipid metabolism and are exposed to an increased cardiometabolic risk. This condition is potentially reversible through the improvement of dietary and behavioural habits. However, a well-assembled nutraceutical would be a useful tool to better improve the metabolic parameters associated to overweight and insulin resistance.

METHODS:

To evaluate the effect of a combined nutraceutical containing berberine, chlorogenic acid and tocotrienols, we performed a double blind, cross-over designed trial versus placebo, in 40 overweight subjects with mixed hyperlipidaemia. After the first 8 weeks of treatment (or placebo), patients were asked to observe a 2-week washout period, and they were then assigned to the alternative treatment for a further period of 8 weeks. Clinical and laboratory data associated to hyperlipidaemia and insulin resistance have been obtained at the baseline, at the end of the first treatment period, after the washout, and again after the second treatment period.

RESULTS:

Both groups experienced a significant improvement of anthropometric and biochemical parameters versus baseline. However, total cholesterol, LDL cholesterol, triglycerides, non-HDL cholesterol, fasting insulin, HOMA-IR, GOT and Lipid Accumulation Product decreased more significantly in the nutraceutical group versus placebo.

CONCLUSIONS:

This combination seems to improve a large number of metabolic and liver parameters on the short-term in overweight subjects. Further studies are needed to confirm these observations on the middle- and long-term.

Ahsan H, Ahad A, Siddiqui WA.

J Chem Biol. 2015 Jan 20;8(2):45-59.

Abstract

Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley and certain types of nuts and grains. Vegetable oils provide the best sources of these vitamin E forms, particularly palm oil and rice bran oil contain higher amounts oftocotrienols. Other sources of tocotrienols include grape fruit seed oil, oats, hazelnuts, maize, olive oil, buckthorn berry, rye, flax seed oil, poppy seed oil and sunflower oil. Tocotrienols are of four types, viz. alpha (α), beta (β), gamma (γ) and delta (δ). Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. A number of researchers have developed methods for the extraction, analysis, identification and quantification of different types of vitamin E compounds. This article constitutes an in-depth review of the chemistry and extraction of the unsaturated vitamin E derivatives, tocotrienols, from various sources using different methods. This review article lists the different techniques that are used in the characterization and purification of tocotrienols such as soxhlet and solid-liquid extractions, saponification method, chromatography (thin layer, column chromatography, gas chromatography, supercritical fluid, high performance), capillary electrochromatography and mass spectrometry. Some of the methods described were able to identify one form or type while others could analyse all the analogues of tocotrienolmolecules. Hence, this article will be helpful in understanding the various methods used in the characterization of this lesser known vitamin E variant.