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A quantitative analysis of the structure-antioxidant activity relationship was performed for 128 derivatives of phenols, amines, uracil, benzopyrane, and benzofuran using the GUSAR 2013 program. Nine statistically significant QSAR consensus models characterized by a high accuracy of prediction of the chain termination rate constant of oxidation on the antioxidant molecules were constructed. The results of the structural analysis performed in the GUSAR 2013 program are in good agreement with the literature data. [ABSTRACT FROM AUTHOR]

The antioxidant properties of 2,4-diphenyl-7,8-benzo-5,6-dihydro(4H)selenochromene, some of its chlorine-containing derivatives, and selected chromilium salts based on these derivatives have been investigated using the initiated oxidation of 1,4-dioxane as a model reaction. The antioxidant activity of these compounds is quantitatively characterized by the apparent inhibition rate constant fk. [ABSTRACT FROM AUTHOR]

The antioxidant properties of conjugates of betulonic and betulinic acids with amido derivatives of the acid Trolox were studied for initiated 1,4-dioxane oxidation as a model reaction. The antioxidant activity of the compounds was characterized in terms of the apparent inhibition rate constant fk. [ABSTRACT FROM AUTHOR]

The antioxidant properties of 20-hydroxyecdysone and its conjugates with (6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde are reported for initiated 1,4-dioxane oxidation as a model reaction. The antioxidant activity of these compounds is characterized in terms of the effective rate constant of inhibition, fk. [ABSTRACT FROM AUTHOR]

The kinetics of 1,4-dioxane oxidation initiated by azodiisobutyronitrile in the temperature range from 323 to 353 K are studied from the rate of oxygen absorption. The oxidation proceeds in the regime of a nonbranched chain reaction with quadratic-law chain termination. The apparent rate constants ( fk 7) of 1,4-dioxane oxidation inhibition by 2,6-ditert-butyl-4-methylphenol and quercitin are measured. Quercitin is not inferior to ionol in inhibition efficiency. [ABSTRACT FROM AUTHOR]

Antioxidant properties of caffeic, ferulic, vanillic, and 4-hydroxybenzoic acids isolated from Larix sibirica Ledeb. bark were studied using model radical-chain reactions for oxidation of propan-2-ol and 1,4-dioxane under kinetic control. Quantitative characteristics of the antioxidant activities were determined as effective rate constants fkIn for oxidation chain termination of the phenolcarboxylic acids. It was found that caffeic acid had the highest antioxidant activity among the investigated natural compounds. [ABSTRACT FROM AUTHOR]

The antioxidant [AO] properties of the ethylacetate extract of Larix sibirica bark and the flavonoids quercetin and dihydroquercetin found in it were studied using a model radical-chain oxidation of propan-2-ol in the kinetic regime. The quantitative characteristics of their AO activity were determined as effective rate constants fkln. It was found that dihydroquercetin had the highest AO activity among the studied natural compounds. [ABSTRACT FROM AUTHOR]

The antioxidant properties of humic substances of low-mineralization sulfidic muds (peloids) were investigated using initiated oxidation of 1,4-dioxane as a model reaction. Four groups of substances including humic, himatomelanic, fulvic, and humus acids were studied. Kinetic characteristics of the oxidation of humic substances were determined in terms of effective inhibition rate constants fk. It is established that himatomelanic acids of peloids exhibit the maximum antioxidant activity among the studied substances. [ABSTRACT FROM AUTHOR]