Tocopherol Derivatives Research Articles

Studies on Tocopherol Derivatives. III. Oxidation of δ-Tocopherol and 6-Hydroxy-2, 2, 8-trimethylchroman

Oxidation reaction of d-δ-tocopherol (I) and δ-tocopherol model compound (II) are carried out with silver nitrate as oxidizing agent in ethyl alcohol. Three novel oxidation products are isolated and characterized. They are atropisomers of (+)-5-(δ-tocopherol-5'-yl)-δ-tocopherol (VII, with R-configuration at C5-C5' position, IX with S-configuration at C5-C5' position), and 5-(6'-hydroxy-2', 2', 8'-trimethylchroman-5'-yl)-6-hydroxy-2, 2, 8-trimethylchroman (XI).

Studies on Tocopherol Derivatives. II. Synthesis of Phosphomethyl Tocopheryl Acetates

Studies on Tocopherol Derivatives. II. Synthesis of Phosphomethyl Tocopheryl Acetates

Studies on Tocopherol Derivatives. I. Conversion of β-, γ-, and δ-Tocopherol to α-Tocopherol

A four-step methylation of β-, γ-, and δ-tocopherol to α-tocopherol is described. All of the intermediates are isolated and characterized. The purities of methylated tocopherols are determined by quantitative gas liquid chromatography. The four steps are Mannich reaction, acetolysis, reductive cleavage, and reduction.

A method of ultraviolet spectrophotometry of lipid monolayers on silica gel.

AbstractA method has been developed for visible and UV spectrophotometry of lipid monolayers after preadsorption on silica gel from solution in hydrocarbon solvents. Lipid‐coated silica gel is made optically transparent in the desired spectral region by slurrying with an inert solvent mixture. Reproducible gels with nearly the same refractive index as the solvent are achieved by careful choice of mixed solvents and carefully timed settling periods. The gel is pipetted into a silica cuvette of 1 cm light path, and a 9 mm silica spacer bar is inserted between Teflon guide strips. Appropriate choice of solvent mixtures (mainly spectral grade cyclohexane and cyclooctane) permits quantitation of spectra down to 2250 Angstrom units, using a silica gel reference cell. Lipid elution from the monolayer into the solvent is usually less than 1% at the dry‐mixing dilutions used. Spectra of known unsaturated carbonyl compounds adsorbed on silica show red shifts as great as 240 Angstrom units, while blue shifts as great as 100 Angstrom units are observed for tocopherol derivatives with an intact aromatic ring. Very small shifts are observed for polyenes. The extent and direction of the shifts are indicative of adsorption and its orientation and are useful in the preliminary determination of the class of an unknown compound. The silica slurry spectra of the important tocopherol oxidation products, the quinone, dimer and trimer, have been examined. Peak wavelength shifts are consistent with structures elsewhere proposed for these compounds.

Participation of tocopherol derivatives in lipolysis

Participation of tocopherol derivatives in lipolysis

In vitro effect of tocopherol metabolites on respiratory decline in dietary necrotic liver degeneration

The latent phase of necrotic liver degeneration in the rat, produced by dietary deficiency of vitamin E and Factor 3, is characterized by respiratory decline, i.e., a failure of respiration of liver slices in the Warburg. Tocopherol readily reverses this defect when injected intravenously but not when added to the Warburg medium. The in vitro effect of various tocopherol derivatives on respiratory decline was investigated. DL-α-tocopherol, d- α-tocopheryl polyethylene glycol-1000 succinate, DL-α-tocopherylhydroquinone, DL-α-tocopherylquinone, and DL-“α-tocopheroxide” (acetal of α-tocopherylquinone) did not influence the breakdown of respiration. Two tocopherol metabolites, isolated from the urines of rabbits and humans, 2-(3-hydroxy-3-methyl-5-carboxy)-pentyl-3,5,6-trimethylbenzoquinone and its γ-lactone, were found to prevent respiratory decline when added to the Warburg medium. A dose response curve was obtained. The 50% effective dose was at approx. 6.25 μg. The diacetate of the hydroquinone of the lactone was active at higher dose levels. The significance of the findings is discussed. In addition to the effect on respiratory decline, the γ-lactone at levels of 100 μg per flask produced a stimulation of the initial O 2 consumption. The stimulatory effect was less pronounced, but present, with liver slices from normal controls.