Oxidation of α‐tocopherol to α‐tocopheryl quinone by carbon tetrachloride‐ethanol solvent

Seward, C. R.; Mitchell, Geraldine V.; Argrett, Loretta C; Hove, E. L.

doi:10.1007/bf02531055

Cited by 3 publications

(2 citation statements)

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“…Tocopherols seemed also to influence other important biophysical membrane characteristics, such as fluidity, in a manner similar to that of cholesterol. Studies of the antioxidant properties led to the recognition that during the reaction of α-tocopherol with an appropriate oxidizing species, α-tocopherol may be oxidized to α-tocopheryl quinine (Seward et al, 1969). In latter studies where peroxidizing lipids were used to induce the formation of antioxidant radicals, electron spin resonance spectroscopy revealed that free radical interactions of dl-α-tocopherol generate dl-α-tocopheroxyl radicals.…”

Section: α -Tocopherol: Riding the Wave For Five Decadesmentioning

confidence: 99%

Tocotrienols: Vitamin E beyond tocopherols

2006

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In nature, eight substances have been found to have vitamin E activity: α-, β-, γ-and δ-tocopherol; and α-, β-, γ-and δ-tocotrienol. Yet, of all papers on vitamin E listed in PubMed less than 1% relate to tocotrienols. The abundance of α-tocopherol in the human body and the comparable efficiency of all vitamin E molecules as antioxidants, led biologists to neglect the non-tocopherol vitamin E molecules as topics for basic and clinical research. Recent developments warrant a serious reconsideration of this conventional wisdom. Tocotrienols possess powerful neuroprotective, anticancer and cholesterol lowering properties that are often not exhibited by tocopherols. Current developments in vitamin E research clearly indicate that members of the vitamin E family are not redundant with respect to their biological functions. α-Tocotrienol, γ-tocopherol, and δ-tocotrienol have emerged as vitamin E molecules with functions in health and disease that are clearly distinct from that of α-tocopherol. At nanomolar concentration, α-tocotrienol, not α-tocopherol, prevents neurodegeneration. On a concentration basis, this finding represents the most potent of all biological functions exhibited by any natural vitamin E molecule. An expanding body of evidence support that members of the vitamin E family are functionally unique. In recognition of this fact, title claims in manuscripts should be limited to the specific form of vitamin E studied. For example, evidence for toxicity of a specific form of tocopherol in excess may not be used to conclude that high-dosage "vitamin E" supplementation may increase all-cause mortality. Such conclusion incorrectly implies that tocotrienols are toxic as well under conditions where tocotrienols were not even considered. The current state of knowledge warrants strategic investment into the lesser known forms of vitamin E. This will enable prudent selection of the appropriate vitamin E molecule for studies addressing a specific need.

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Section: α -Tocopherol: Riding the Wave For Five Decadesmentioning

confidence: 99%

Tocotrienols: Vitamin E beyond tocopherols

2006

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“…and C-7 relative to those in Table II references therein]; and it can be generated by reaction of EH with the hepatotoxin CCI 4 [102] and during oxidation of EH with NO 2 [103]. Vitamin E has been proposed to protect lung tissue from damage by NO 2 in polluted air by reaction to form this quinone [74].…”

Section: A Formation Of the ~-Tocopheroxyl Radicalmentioning

confidence: 99%