Search results for "Tocopherol"
showing 10 items of 93 documents
Induction of oxiapoptophagy, a mixed mode of cell death associated with oxidative stress, apoptosis and autophagy, on 7-ketocholesterol-treated 158N …
2013
7-Ketocholesterol (7KC) has been suggested to induce a complex mode of cell death on monocytic cells: oxiapoptophagy (OXIdation, APOPTOsis, and autoPHAGY) (Monier et al. (2003) [12]). The aim of the present study, realized on 158N murine oligodendrocytes, was to bring new evidence on this mixed form of cell death. On 158N cells, 7KC induces an overproduction of reactive oxygen species (ROS) revealed by dihydroethidium staining, a loss of transmembrane mitochondrial potential measured with DiOC6(3), caspase-3 activation, and condensation and/or fragmentation of the nuclei which are typical criteria of oxidative stress and apoptosis. Moreover, 7KC enhances cytoplamic membrane permeability to …
Prevention of 7-ketocholesterol-induced side effects by natural compounds
2018
Cholesterol oxidation products, also named oxysterols, can be formed either by cholesterol auto-oxidation, enzymatically or both. Among these oxysterols, 7-ketocholesterol (7KC) is mainly formed during radical attacks that take place on the carbon 7 of cholesterol. As increased levels of 7KC have been found in the tissues, plasma and/or cerebrospinal fluid of patients with major diseases, especially age-related diseases (cardiovascular diseases, eye diseases, neurodegenerative diseases), some cancers, and chronic inflammatory diseases, it is suspected that 7KC, could contribute to their development. Since 7KC, provided by the diet or endogenously formed, is not or little efficiently metabol…
Absence of correlation between oxysterol accumulation in lipid raft microdomains, calcium increase, and apoptosis induction on 158N murine oligodendr…
2013
There is some evidence that oxidized derivatives of cholesterol, 7-ketocholesterol (7KC) and 7β-hydroxycholesterol (7βOHC), are increased in the plasma of patients with neurodegenerative diseases associated with demyelinization of the central nervous system (CNS). It was therefore of interest to investigate the effects of these oxysterols on oligodendrocytes, the myelin-forming cells in the CNS. To this end, 158N murine oligodendrocytes were treated with 7KC or 7βOHC inducing an apoptotic mode of cell death characterized by condensation/fragmentation of the nuclei, dephosphorylation of Akt and GSK3, mitochondrial depolarization involving Mcl-1, and caspase-3 activation. In contrast, under t…
α-Tocopherol impairs 7-ketocholesterol-induced caspase-3-dependent apoptosis involving GSK-3 activation and Mcl-1 degradation on 158N murine oligoden…
2011
Abstract In important and severe neurodegenerative pathologies, 7-ketocholesterol, mainly resulting from cholesterol autoxidation, may contribute to dys- or demyelination processes. On various cell types, 7-ketocholesterol has often been shown to induce a complex mode of cell death by apoptosis associated with phospholipidosis. On 158N murine oligodendrocytes treated with 7-ketocholesterol (20 μg/mL corresponding to 50 μM, 24–48 h), the induction of a mode of cell death by apoptosis characterised by the occurrence of cells with condensed and/or fragmented nuclei, caspase activation (including caspase-3) and internucleosomal DNA fragmentation was observed. It was associated with a loss of tr…
7-Ketocholesterol Incorporation into Sphingolipid/Cholesterol-enriched (Lipid Raft) Domains Is Impaired by Vitamin E
2009
Cholesterol oxides, in particular 7-ketocholesterol, are proatherogenic compounds that induce cell death in the vascular wall when localized in lipid raft domains of the cell membrane. Deleterious effects of 7-ketocholesterol can be prevented by vitamin E, but the molecular mechanism involved is unclear. In this study, unlike γ-tocopherol, the α-tocopherol vitamin E form was found to prevent 7-ketocholesterol-mediated apoptosis of A7R5 smooth muscle cells. To be operative, α-tocopherol needed to be added to the cells before 7-ketocholesterol, and its anti-apoptotic effect was reduced and even suppressed when added together or after 7-ketocholesterol, respectively. Both pre- and co-treatment…
Radical cations of vitamin E
2002
Radical cations of vitamin E compounds (α-, β-, γ- and δ-tocopherols and α-, β-, γ- and δ-tocotrienols) were for the first time successfully prepared in different solvents. Their unpaired electron distribution was solved by means of EPR and ENDOR spectroscopy and assignment of isotropic hyperfine couplings was performed. The isotropic hyperfine coupling constants calculated theoretically (UB3LYP) were comparable to those studied experimentally. Radical cations were observed to exist as an intermediate product in the formation of the neutral radical. Moreover, loosening the proton from the radical cation of α-tocopherol and from α-tocotrienol produced the neutral radical, which was detected …
Development and validation of a fast and sensitive chromatographic assay for all-trans-retinol and tocopherols in human serum/plasma using liquid-liq…
2002
A sensitive HPLC assay for all-trans-retinol, a-tocopherol, and g-tocopherols in human serum and plasma is reported. Sample preparation is performed in one step and involves precipitation of proteins and extraction of lipids with two volumes of an ethanol–chloroform mixture (3:1, v/v) without I.S. addition. After removal of the precipitated protein, 20 ml aliquots of the supernatant (equivalent to 6.7 ml of serum or plasma) were injected into the HPLC system and analyzed using fluorometric detection. RP-HPLC was performed using a C18 S3 ODS2 column with a methanol–water step gradient (97:3 to 100) at 1.0 ml/min. The quantification limit expressed as nanograms of analyte per milliliter of se…
Chemical properties and oxidative stability of Arjan ( Amygdalus reuteri ) kernel oil as emerging edible oil
2017
The oxidative stability, as well as the chemical composition of Amygdalus reuteri kernel oil (ARKO), were evaluated and compared to those of Amygdalus scoparia kernel oil (ASKO) and extra virgin olive oil (EVOO) during and after holding in the oven (170 °C for 8 h). The oxidative stability analysis was carried out by measuring the changes in conjugated dienes, carbonyl and acid values as well as oil/oxidative stability index and their correlation with the antioxidant compounds (tocopherol, polyphenols, and sterol compounds). The oleic acid was determined as the predominant fatty acid of ARKO (65.5%). Calculated oxidizability value and an iodine value of ARKO, ASKO and EVOO were reported as …
Fatty acids, sterols and antioxidant compounds of minor and neglected cultivar of Sicilian virgin olive oils
2007
Acidic and sterol composition, pigment fraction and antioxidant compounds (tocopherols, total phenols and polar phenols) from eight monovarietal Sicilian olive oil samples, analyzed during the crop seasons from 2003/2004 to 2005/2006, are reported. Cultivars were divided, according to their diffusion, in main, minor and neglected cultivars. Encouraging data were observed for minor and neglected cultivars, for some revaluation in regard to their relevance, because they showed the highest content in tocopherols, in total phenols and polar phenols compared with main cultivars.
HPLC PROFILE AND EVOLUTION DURING STORAGE OF TRIGLYCERIDES AND DIGLYCERIDES IN VIRGIN OLIVE OILS
2007
Acidic and sterol composition, pigment fraction and antioxidant compounds (tocopherols, total phenols and polar phenols) from eight monovarietal Sicilian olive oil samples, analyzed during the crop seasons from 2003/2004 to 2005/2006, are reported. Cultivars were divided, according to their diffusion, in main, minor and neglected cultivars. Encouraging data were observed for minor and neglected cultivars, for some revaluation in regard to their relevance, because they showed the highest content in tocopherols, in total phenols and polar phenols compared with main cultivars.