Antioxidant activity of phenols related to vitamin E. Are there chain-breaking antioxidants better than .alpha.-tocopherol?

1983 ◽  
Vol 105 (18) ◽  
pp. 5950-5951 ◽  
Author(s):  
Graham W. Burton ◽  
Lise Hughes ◽  
Keith U. Ingold
Keyword(s):  
Antioxidant Activity ◽  
Vitamin E ◽  
Alpha Tocopherol ◽  
Chain Breaking ◽  
Better Than

Vitamin E, Atherosclerosis and Thrombosis

2001 ◽  
Vol 85 (05) ◽  
pp. 766-770 ◽  
Author(s):  
Fausta Micheletta ◽  
Luigi Iuliano ◽  
Francesco Violi
Keyword(s):  
Biological Activity ◽  
Vitamin E ◽  
Daily Intake ◽  
Atherosclerotic Lesion ◽  
Redox Status ◽  
Oxidative Modification ◽  
Alpha Tocopherol ◽  
Ldl Oxidation ◽  
Alternative Mechanism ◽  
Chain Breaking

SummaryVitamin E, a major lipid-soluble, chain-breaking antioxidant includes several tocopherols having the biological activity of RRR-alpha-tocopherol. Vitamin E circulates in the blood as free tocopherol bound to beta-lipoproteins and is present in cell membrane where it exerts a potent defence against lipid peroxidation (1). Blood concentration of vitamin E in humans ranges from 25 to 30 μM, depending on daily intake and body’s ability to absorb fat (1). In the last decade the scientific interest on biological activity of vitamin E increased because of a growing body of evidence linking this vitamin with atherosclerosis and its complications (2). Thus, the oxidative hypothesis of atherosclerosis suggests that LDL accumulates within vessel wall, in particular in the macrophages, as a consequence of its oxidative modification mediated by resident cells (3, 4). A reduced defence against LDL oxidation could favour this process and accelerate atherosclerotic progression. Accordingly, patients with coronary heart disease have lower plasma concentration of vitamin E than controls (2) and prospective studies demonstrated that a daily assumption of vitamin E reduces cardiovascular events (5). According to the oxidative hypothesis of atherosclerosis, this effect has been attributed to the inhibition of LDL oxidation. Alternative mechanism potentially implicated in the antiatherosclerotic activity of vitamin E includes its interference with the activity of platelet and monocyte, in which the intracellular redox status plays an important functional role (6, 7). As platelets and monocytes are both involved in the pathophysiologic process leading to atherosclerotic lesion, the interference of vitamin E with the biological function of these cells may represent another important tool to explore the anti-atherosclerotic activity of vitamin E. This review will focus on the open issues related to the use of vitamin E in clinical studies and the potential usefulness in investigating platelet function and clotting activation in patients treated with vitamin E.

Phytoconstituents screening and in-vitro evaluation of total antioxidant activity of marine red algae Gracilaria fergusonii J. Agardh

2017 ◽  
Vol 6 (1) ◽  
pp. 9 ◽  
Author(s):  
Jenifer Panneer ◽  
C. P. Balakrishnan
Keyword(s):  
Antioxidant Activity ◽  
Fatty Acid ◽  
Vitamin E ◽  
Amino Acid ◽  
Red Algae ◽  
Alpha Tocopherol ◽  
Total Antioxidant Activity ◽  
Phytochemical Screening ◽  
Total Antioxidant

Evaluation of various organic solvent extracts of marine red algae Gracilaria fergusonii used for priliminary screening of phytoconstituents and in-vitro total antioxidant activity. The phytochemical screening was carried out by cooling percolation extraction using different solvents like acetone, ethanol, chloroform, petroleum ether, benzene, methanol and water. The standard regression of alpha tocopherol gives linear regression [y=0.0004x + 0.0807 (R2= 0.9814)] obtained and used to calculate the standard and the total antioxidant activity are expressed as equivalents of vitamin E (µg g-1). The present study reavealed that most of the phytochemicals like alkaloids,  coumarin, flavonoids, phenol, quinons, steroids, saponin, tannins, glycosides, amino acid, sugar, protein and fatty acid were present in the dried algal sample. The total antioxidant activity was done by phosphomolybdate method using α- tocopherol as standard. Keywords: Gracilaria fergusonii, phytoconstituents, antioxidant, α-tocopherol

THE EFFECT OF UNSATURATION OF DIETARY FAT AND OF ANTIOXIDANTS ON THE DEVELOPMENT OF LIVER DAMAGE

1959 ◽  
Vol 37 (1) ◽  
pp. 493-499 ◽  
Author(s):  
L. S. Valberg ◽  
Rose A. Young ◽  
J. M. R. Beveridge
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Antioxidant Activity ◽  
Vitamin E ◽  
Liver Damage ◽  
Dietary Fat ◽  
Unsaturated Fatty Acids ◽  
Alpha Tocopherol ◽  
Liver Necrosis ◽  
Gamma Tocopherol

The addition of unsaturated fatty acids, even in small amounts, to diets low in vitamin E, selenium, and the sulphur-containing amino acids greatly accelerated the development of acute liver necrosis in rats. The production of this lesion was shown also to be affected in a similar manner by the nature of the dietary fat in the ration consumed immediately prior to the removal of protective substances such as the sulphur-containing amino acids; unsaturated fatty acids or lipid again acted as predisposing factors.Gamma-tocopherol incorporated in the diet at a level of 0.02% and injected at a level of 1.5 mg/rat/day was equally as effective as alpha-tocopherol in preventing liver necrosis. The protective effect of gamma-tocopherol against the development of liver necrosis lends support to the thesis that alpha-tocopherol protects against liver damage by virtue of its antioxidant activity.

THE EFFECT OF UNSATURATION OF DIETARY FAT AND OF ANTIOXIDANTS ON THE DEVELOPMENT OF LIVER DAMAGE

1959 ◽  
Vol 37 (3) ◽  
pp. 493-499 ◽  
Author(s):  
L. S. Valberg ◽  
Rose A. Young ◽  
J. M. R. Beveridge
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Antioxidant Activity ◽  
Vitamin E ◽  
Liver Damage ◽  
Dietary Fat ◽  
Unsaturated Fatty Acids ◽  
Alpha Tocopherol ◽  
Liver Necrosis ◽  
Gamma Tocopherol

The addition of unsaturated fatty acids, even in small amounts, to diets low in vitamin E, selenium, and the sulphur-containing amino acids greatly accelerated the development of acute liver necrosis in rats. The production of this lesion was shown also to be affected in a similar manner by the nature of the dietary fat in the ration consumed immediately prior to the removal of protective substances such as the sulphur-containing amino acids; unsaturated fatty acids or lipid again acted as predisposing factors.Gamma-tocopherol incorporated in the diet at a level of 0.02% and injected at a level of 1.5 mg/rat/day was equally as effective as alpha-tocopherol in preventing liver necrosis. The protective effect of gamma-tocopherol against the development of liver necrosis lends support to the thesis that alpha-tocopherol protects against liver damage by virtue of its antioxidant activity.

scholarly journals Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 589 ◽  
Author(s):  
Aneta Baj ◽  
Jakub Cedrowski ◽  
Ewa Olchowik-Grabarek ◽  
Artur Ratkiewicz ◽  
Stanislaw Witkowski
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Vitamin E ◽  
Density Functional ◽  
Lone Pair ◽  
Hydrogen Atom Transfer ◽  
Hydroxyl Group ◽  
Styrene Oxidation ◽  
Chain Breaking

Vitamin E is the most active natural lipophilic antioxidant with a broad spectrum of biological activity. α-Tocopherol (α-T), the main representative of the vitamin E family, is a strong inhibitor of lipid peroxidation as a chain-breaking antioxidant. Antioxidant and antiradical properties of vitamin E result from the presence of a phenolic hydroxyl group at the C-6 position. Due to stereoelectronic effects in the dihydropyranyl ring, the dissociation enthalpy for phenolic O–H bond (BDEOH) is reduced. The high chain-breaking reactivity of α-T is mainly attributed to orbital overlapping of the 2p-type lone pair on the oxygen atom (O1) in para position to the phenolic group, and the aromatic π-electron system. The influence of the O1 atom on the antioxidant activity of vitamin E was estimated quantitatively. The all-rac-1-carba-α-tocopherol was synthesized for the first time. Along with model compounds, 1-carba-analog of Trolox and its methyl ester were screened for their in vitro antioxidant activity by inhibition of styrene oxidation, and for the radical-reducing properties by means of 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging assay. To study the antioxidant activity, density functional theory (DFT) was also applied. Reaction enthalpies related to HAT (hydrogen atom transfer), SET–PT (sequential electron transfer—proton transfer), and SPLET (sequential proton loss—electron transfer) mechanisms were calculated.

Alpha Tocopherol Loaded in Liposome: Preparation, Optimization, Characterization and Sperm Motility Protection

2020 ◽  
Vol 10 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Lamia Taouzinet ◽  
Sofiane Fatmi ◽  
Allaeddine Khellouf ◽  
Mohamed Skiba ◽  
Mokrane Iguer-ouada
Keyword(s):  
Vitamin E ◽  
Sperm Motility ◽  
High Performance ◽  
Positive Impact ◽  
Alpha Tocopherol ◽  
Ethanol Injection ◽  
Liposome Preparation ◽  
Liposome Size ◽  
Optimum Solution ◽  
The Impact

Background: Alpha-tocopherol is a potent antioxidant involved in sperm protection particularly during cryopreservation. However, its poor solubility limits the optimal protection in aqueous solutions. Objective: The aim of this study was to enhance the solubility of α-tocopherol by the use of liposomes. Methods: The experimental approach consisted to load vitamin E in liposomes prepared by ethanol injection method and the optimization carried out by an experimental design. The optimum solution was characterized by high performance liquid chromatography and scanning electron microscope. Finely, the impact on sperm motility protection was studied by the freezing technic of bovine sperm. Results: The optimum solution was obtained when using 10.9 mg/ml of phospholipids, 1.7 mg/ml of cholesterol and 2 mg/ml of vitamin E. The liposome size was 99.86 nm, providing 78.47% of loaded efficiency. The results showed also a significant positive impact on sperm motility after hours of preservation. Conclusion: In conclusion, the current results showed the interest of liposome preparation as an alternative to enhance vitamin E solubility and to protect spermatozoa during cryopreservation.

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