Biological potenices of ε- and ζ<sub>1</sub>-tocopherol and 5-methyltocol

Bunyan, J.; McHale, D.; Green, J.; Marcinkiewicz, S.

doi:10.1079/bjn19610030

Cited by 94 publications

(36 citation statements)

References 26 publications

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“…There is also vitamin E of synthesis, made up of approximately an equal mixture of 8 steroisomer forms of a-tocopherol. The most abundant form of vitamin E in nature is RRR-a-tocopherol (72), that has the highest biological activity on the basis of rat fetal-resorption assay (17) and reverses vitamin E deficiency symptoms in humans (68,73). Biological and antioxidant activities are not coincident among the different vitamin E forms.…”

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confidence: 99%

“…Biological and antioxidant activities are not coincident among the different vitamin E forms. Thus, whereas y-tocopherol (a form that is abundant in human diet) has about half of the antioxidant capacity of a-tocopherol activity (18), it only has one tenth of its biological activity (17) and although the various synthetic a-tocopherol forms have different biological activities, they have similar antioxidant activity. The 8 isomers of vitamin E are widely distributed in nature.…”

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confidence: 99%

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Vitamin E: action, metabolism and perspectives

Herrera

Barbas

2001

J. Physiol. Biochem.

341

197

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Natural vitamin E includes four tocopherols and four tocotrienols. RRR-alpha-tocopherol is the most abundant form in nature and has the highest biological activity. Although vitamin E is the main lipid-soluble antioxidant in the body, not all its properties can be assigned to this action. As antioxidant, vitamin E acts in cell membranes where prevents the propagation of free radical reactions, although it has been also shown to have pro-oxidant activity. Non-radical oxidation products are formed by the reaction between alpha-tocopheryl radical and other free radicals, which are conjugated to glucuronic acid and excreted through the bile or urine. Vitamin E is transported in plasma lipoproteins. After its intestinal absorption vitamin E is packaged into chylomicrons, which along the lymphatic pathway are secreted into the systemic circulation. By the action of lipoprotein lipase (LPL), part of the tocopherols transported in chylomicrons are taken up by extrahepatic tissues, and the remnant chylomicrons transport the remaining tocopherols to the liver. Here, by the action of the "alpha-tocopherol transfer protein", a major proportion of alpha-tocopherol is incorporated into nascent very low density lipoproteins (VLDL), whereas the excess of alpha-tocopherol plus the other forms of vitamin E are excreted in bile. Once secreted into the circulation, VLDL are converted into IDL and LDL by the action of LPL, and the excess of surface components, including alpha-tocopherol, are transferred to HDL. Besides the LPL action, the delivery of alpha-tocopherol to tissues takes place by the uptake of lipoproteins by different tissues throughout their corresponding receptors. Although we have already a substantial information on the action, effects and metabolism of vitamin E, there are still several questions open. The most intriguing is its interaction with other antioxidants that may explain how foods containing small amounts of vitamin E provide greater benefits than larger doses of vitamin E alone.

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confidence: 99%

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confidence: 99%

Vitamin E: action, metabolism and perspectives

Herrera

Barbas

2001

J. Physiol. Biochem.

341

197

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“…Use of this assay has established (Bunyan et al 1961;Century & Horwitt, 1965) that the relative order of bioactivity of the tocopherols is a>p>y>G. The tocotrienols are muck less abundant and, of these, only the a-and p-tocotrienols have been tested. Again, the a-form is most active, but it is substantially less active than its tocopherol counterpart.…”

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confidence: 99%

Vitamin E: molecular and biological function

Burton

1994

Proc. Nutr. Soc.

169

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“…On day 1, no difference in blood gas values was found between Groups 3 and 4, but the pH, pO 2 , and HCO 3 -levels were decreased and pCO 2 was increased in Group 4 compared with Group 1 (P < 0.05). The next day, there was a significant difference between Groups 3 and 4 in pH and pO 2 Both bronchoalveolar lavage inflammatory cell count and histopathological examination score revealed no Table 1. Tissue and serum nitric oxide (NO) levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in pulmonary contusion injury in rats (n = 7 and mean ± SD).…”

Section: Resultsmentioning

confidence: 99%

“…Tocopherols have antioxidant features and they have been demonstrated to be effective in treatment of chronic diseases associated with oxidative stress (2). Because of its antioxidant activity, the role of vitamin E in prevention of chronic diseases, particularly those thought to have an oxidative stress component such as atherosclerosis and cardiovascular diseases, has been widely studied.…”

Section: Introductionmentioning

confidence: 99%

Vitamin E modulates lung oxidative stress, serum copper, zinc, and iron levels in rats with pulmonary contusion

Sırmalı

Solak²,

Çevik³

et al. 2015

Turk J Med Sci

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Background/aim: To evaluate the effects of oxidant/antioxidant mechanisms and levels of trace elements on trauma-stimulated moderate pulmonary contusions after vitamin E administration.Materials and methods: Sixty-three male Sprague Dawley rats were used. Animals were studied in 4 groups. Vitamin E (150 mg/kg) was injected intraperitoneally 30 min after trauma and on the first and second days. Blood samples were obtained for nitric oxide (NO) levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. Zinc (Zn +2 ), copper (Cu +2 ), and iron (Fe +3 ) were measured in serum.Results: Lung contusion increased serum and tissue NO levels and SOD activities and decreased GSH-Px activities (P < 0.05). Vitamin E significantly (P < 0.05) decreased NO levels and SOD activities and increased GSH-Px. Serum Zn +2 , Cu +2 , and Fe +3 levels were statistically significantly influenced by the administration of vitamin E (P < 0.05). Group 4 had lower scores compared to Group 3 (P < 0.05) and no difference compared to Group 1 (P > 0.05). Conclusion:These results suggest that treatment with vitamin E reduces lung oxidative stress and related mechanisms in isolated lung contusion as demonstrated by an experimental rat model.

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Biological potenices of ε- and ζ₁-tocopherol and 5-methyltocol

Cited by 94 publications

References 26 publications

Vitamin E: action, metabolism and perspectives

Vitamin E: action, metabolism and perspectives

Vitamin E: molecular and biological function

Vitamin E modulates lung oxidative stress, serum copper, zinc, and iron levels in rats with pulmonary contusion

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Biological potenices of ε- and ζ1-tocopherol and 5-methyltocol

Cited by 94 publications

References 26 publications

Vitamin E: action, metabolism and perspectives

Vitamin E: action, metabolism and perspectives

Vitamin E: molecular and biological function

Vitamin E modulates lung oxidative stress, serum copper, zinc, and iron levels in rats with pulmonary contusion

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Product

Resources

About

Biological potenices of ε- and ζ₁-tocopherol and 5-methyltocol