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Radical Generator (radical + generator)
Selected AbstractsUBIQUINONE-10 AS AN ANTIOXIDANT,JOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2008DAVID PETILLO ABSTRACT Ubiquinol, the reduced form of coenzyme Q, is known as a lipid antioxidant. Its fully oxidized form, ubiquinone, would theoretically not have this activity. However, we report that ubiquinone-10, the oxidized form of coenzyme Q, demonstrated antioxidant activity in model studies against a lipid-soluble free radical generator, 2,2,-azobis(2,4-dimethylvaleronitrile). This was demonstrated at both 1:100 and 1:1,000 ratios of ubiquinone-10 to lipid (for both methyl linoleate and methyl linolenate). Ubiquinone-10 should therefore not be discounted as a possible antioxidant in more complex systems such as food. PRACTICAL APPLICATIONS Coenzyme Q (ubiquinol/ubiquinone) is an important component of electron transport in biological tissues and is also classified as a potent antioxidant. It is generally believed that the form that is active as an antioxidant is the reduced ubiquinol. In evaluating the loss of antioxidants in mackerel light and dark muscle tissues, it was observed that the oxidized form, ubiquinone, comprised over 87% of the total coenzyme Q in light muscle and over 93% in dark muscle and this observation did not change under anaerobic conditions. This study was done to determine if the oxidized form of coenzyme Q, ubiquinone, was capable of acting as an antioxidant. In this study, it is shown that it can function in this manner. [source] Photochemical attachment of polymers on planar surfaces with a covalently anchored monolayer of a novel naphthyl ketone photochemical radical generatorJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2004K. Dayananda Abstract A monolayer of covalently anchored, novel, binaphthyl ketone is used as a surface-confined photochemical radical generator (PRG) for anchoring a variety of polymers to silicon surfaces. The precursor PRG is synthesized by the application of a facile and novel method for the oxidation of sterically hindered benzylic hydrocarbons to carbonyl compounds. Oxidation was carried out with a stoichiometric amount of potassium peroxydisulfate, in the presence of a catalytic amount of copper sulfate in an acetonitrile/water mixture. The PRG synthesized is characterized by 1H NMR, UV, and Fourier transform infrared (FTIR). The covalently attached monolayers are characterized by X-ray photoelectron spectroscopy, ellipsometry, and water contact angle measurements. The method developed is applicable to the preparation of a monolayer of a variety of polymers on a wide range of substrates carrying surface hydroxyl groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5413,5423, 2004 [source] Total hydroxyoctadecadienoic acid as a marker for lipid peroxidation in vivoBIOFACTORS, Issue 1-4 2005Yasukazu Yoshida Abstract An improved method for the measurement of lipid peroxidation in vivo has been recently developed, where total hydroxyoctadecadienoic acid (HODE) and 7-hydroxycholesterol (FCOH) were determined by GC/MS analysis from physiological samples after reduction with sodium borohydride and saponification by potassium hydroxide. In this method, both free and ester forms of hydroperoxides and ketones as well as hydroxides of linoleic acid and cholesterol are measured as HODE and FCOH, respectively. The ratio of stereo-isomer, (Z, E)-HODE/(E, E)-HODE, could be also measured. In the present study, in order to examine the effect of continuous, slow flux of free radicals in vivo, a water-soluble radical generator was administered to rats and mice and the amounts of HODE and 8-isoprostane in plasma and liver were measured. It was found that the administration of free radical-generating azo compound increased the level of HODE and decreased the (Z, E)-HODE/(E, E)-HODE ratio in both plasma and liver. The level of HODE was much higher than 8-isoprostane. [source] Scavenging of reactive oxygen species by novel indolin-2-one and indoline-2-thione derivatives,BIOPOLYMERS, Issue 4 2005Hassan Y. Aboul-Enein Abstract The antioxidant behavior of a series of new synthesized substituted indoline-2-ones and indolin-2-thiones was investigated in this study using an oxygen radical absorbance capacity assay (ORAC) and 2,2,-azobis(2-amidino-propane) dihydrochloride (AAPH) as the radical generator; system generating superoxide anion radical, (18-crown-6/KO2/DMSO), and the Fenton-like reaction [Co(II) + H2O2 , Co(III) + HO, + HO,]. Measurements were done using fluorescence, chemiluminescence methods, and a deoxyribose assay based on the spectrophotometry method, respectively. The results obtained indicated that the examined indoline derivatives had effective activities as radical scavengers and may be considered as an effective source for combating oxidative damage. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 171,178, 2005 [source] | ||||||||||