Vitamin E Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin E, including details on benefits, dosage, supplements, antioxidants.

Intersection of the tocopherol and plastoquinol metabolic pathways at the plastoglobule.

Zbierzak AM, Kanwischer M, Wille C, Vidi PA, Giavalisco P, Lohmann A, Briesen I, Porfirova S, Bréhélin C, Kessler F, Dörmann P

Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Karlrobert-Kreiten-Strasse 13, 531115 Bonn, Germany.

Plastoglobules, lipid-protein bodies in the stroma of plant chloroplasts, are enriched in non-polar lipids, in particular prenyl quinols. In the present study we show that, in addition to the thylakoids, plastoglobules also contain a considerable proportion of the plastidial PQ-9 (plastoquinol-9), the redox component of photosystem II, and of the cyclized product of PQ-9, PC-8 (plastochromanol-8), a tocochromanol with a structure similar to gamma-tocopherol and gamma-tocotrienol, but with a C-40 prenyl side chain. PC-8 formation was abolished in the Arabidopsis thaliana tocopherol cyclase mutant vte1, but accumulated in VTE1-overexpressing plants, in agreement with a role of tocopherol cyclase (VTE1) in PC-8 synthesis. VTE1 overexpression resulted in the proliferation of the number of plastoglobules which occurred in the form of clusters in the transgenic lines. Simultaneous overexpression of VTE1 and of the methyltransferase VTE4 resulted in the accumulation of a compound tentatively identified as 5-methyl-PC-8, the methylated form of PC-8. The results of the present study suggest that the existence of a plastoglobular pool of PQ-9, along with the partial conversion of PQ-9 into PC-8, might represent a mechanism for the regulation of the antioxidant content in thylakoids and of the PQ-9 pool that is available for photosynthesis.

Published 22 December 2009 in Biochem J, 425(2): 389-99.
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Articles on Vitamin E published 20 November 2009:

The protective effect of alpha-tocopherol against dichromate-induced renal tight junction damage is mediated via ERK1/2.   Toxicol Lett, 191(2): 279-88.

Renal tight junctions (TJ) play a central role in modulating the paracellular pathway. We examined the function, quantity and distribution of TJ proteins: occludin and claudin-2 (cln-2), on proximal tubule in a model of acute renal failure (ARF) associated with oxidative damage. Since ERK1/2-p modulates TJ integrity, we studied their participation in dichromate (Cr(6+)) toxicity. We evaluated whether co-administration of the antioxidant alpha-tocopherol (alpha-TOC) prevents Cr(6+) toxicity in ... [Abstract] [Full-text]

Articles on Vitamin E published 10 November 2009:

Effect of vitamin E supplement in diet on antioxidant ability of testis in Boer goat.   Anim Reprod Sci, 117(1): 90-4.

The aim of this study was to evaluate the supplementation of Vitamin E in diet on the antioxidant capacity of testis in Boer goat. Twenty-four healthy, Boer male kids of similar body weight (BW) were selected at 3 months of age from the kid flock. Kids were born from does treated with simultaneous flushing and artificial insemination technology. The Boer kids were divided into four groups randomly, supplemented with 0, 80, 320 and 880 IU kid(-1)d(-1) Vitamin E, which were labeled as Groups 1, ... [Abstract] [Full-text]

Articles on Vitamin E published 27 October 2009:

Antioxidants and aging: NMR-based evidence of improved skeletal muscle perfusion and energetics.   Am J Physiol Heart Circ Physiol, 297(5): H1870-5.

We sought to examine the potential role of oxidative stress on skeletal muscle function with advancing age. Nuclear magnetic resonance (NMR) was employed to simultaneously assess muscle perfusion (arterial spin labeling) and energetics ((31)P NMR spectroscopy) in the lower leg of young (26 + or - 5 yr, n = 6) and older (70 + or - 5 yr, n = 6) healthy volunteers following the consumption of either placebo (PL) or an oral antioxidant (AO) cocktail (vitamins C and E and alpha-lipoic acid), ... [Abstract] [Full-text]

Articles on Vitamin E published 26 October 2009:

Effect of alpha tocopherol acetate in Walker 256/B cells-induced oxidative damage in a rat model of breast cancer skeletal metastases.   Chem Biol Interact, 182(2): 98-105.

The pathophysiological changes and the oxidative-antioxidative status were evaluated in the bone microenvironment of rat inoculated with Walker 256/B mammary gland carcinoma cells, and used alpha-tocopherol acetate (ATA) as a countermeasure. Walker 256/B cells were injected into the right femora of aged male rats. Animals were randomized into three groups: 12 rats were injected with saline (control group); 14 rats were injected with Walker 256/B cells (5x10(4)) in the medullar cavity (W256 ... [Abstract] [Full-text]

Articles on Vitamin E published 23 October 2009:

Monocomponent hexa- and dodecaethylene glycol succinyl-tocopherol esters: self-assembly structures, cellular uptake and sensitivity to enzyme hydrolysis.   Biochem Pharmacol, 78(12): 1464-74.

We have chemically synthesized two water-soluble forms of tocopherol succinate linked via an ester bond to hexaethylene glycol and dodecaethylene glycol. The self-assembly structure of the former in water is vesicular, whereas the latter forms elongated micelles. We treated Caco-2 cells with these compounds in these physical forms, in addition to a mixed micelle form. The intact compounds were taken up into the cells, influenced by both the chain length and the physical structure. In addition, ... [Abstract] [Full-text]

Articles on Vitamin E published 19 October 2009:

Multi-component analysis (sterols, tocopherols and triterpenic dialcohols) of the unsaponifiable fraction of vegetable oils by liquid chromatography-atmospheric pressure chemical ionization-ion trap mass spectrometry.   Talanta, 80(2): 924-34.

A simple and sensitive method for the analysis of sterols, tocopherols and triterpenic dialcohols from the unsaponifiable fraction from oil samples in a single analytical run using liquid chromatography coupled to mass spectrometry was developed. With this method, the compounds could be detected directly after dissolving the unsaponifiable fraction in acetonitrile without necessity of time-consuming sample pre-treatment or derivatization. Separation of the analytes was carried out at room ... [Abstract] [Full-text]

Articles on Vitamin E published 13 October 2009:

Functional polymorphism in manganese superoxide dismutase and antioxidant status: their interactions on the risk of cervical intraepithelial neoplasia and cervical cancer.   Gynecol Oncol, 115(2): 272-6.

OBJECTIVE: Manganese superoxide dismutase (MnSOD), the primary antioxidant enzyme in mitochondria, plays a key role in protecting cells from oxidative stress. Furthermore, the MnSOD rs4880 polymorphism is associated with enzyme activity. The authors evaluated the interaction between MnSOD genotypes and cervical carcinogenesis risk and the modulating effects of serum antioxidant nutrient status (beta-carotene, lycopene, zeaxanthin/lutein, retinol, alpha-tocopherol and gamma-tocopherol). METHODS: ... [Abstract] [Full-text]

Articles on Vitamin E published 24 September 2009:

Aerosol delivery of liposomal formulated paclitaxel and vitamin E analog reduces murine mammary tumor burden and metastases.   Exp Biol Med (Maywood), 234(10): 1244-52.

Paclitaxel is a chemotherapeutic agent used for the treatment of metastatic breast cancer. 2,5,7,8-Tetramethyl-2R-(4R, 8R-12-trimethyltridecyl) chroman-6-yloxyacetic acid (alpha-TEA) is an analog of vitamin E that inhibits primary tumor growth and the incidence of lymphatic and pulmonary metastases in preclinical animal models. Here, the efficacy of sequential treatment with paclitaxel and alpha-TEA was tested in the BALB/c syngeneic 66cl-4-GFP mammary cancer model. Both agents were formulated ... [Abstract] [Full-text]

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