Kinetic modeling of the reversal of antioxidant potency of α-, β-, γ- and δ-tocopherols in methyl linoleate peroxidation.

Extended, chemically detailed kinetic models at the molecular basis are constructed to identify the reactions involved in the reversal of the antioxidant action of α-, β-, γ- and δ-tocopherols during methyl linoleate oxidation. The reaction mechanisms were numerically simulated and subjected to analysis to quantify the significance of individual chemical steps by the value-based method. Results of the obtained kinetic models agreed well with the experimental data.

Antioxidant Properties of Selenophene, Thiophene and Their Aminocarbonitrile Derivatives.

The oxygen radical absorbance capacity (ORAC) method was used to detect the antiperoxyradical ability of organoselenium compounds: selenophene and its derivative, 2-amino-4,5,6,7-tetrahydro-1-selenophene-3-carbonitrile (ATSe); while as a comparison, the sulfur-containing analogue of selenophene-thiophene and its derivative-2-amino-4,5,6,7-tetrahydro-1-thiophene-3-carbonitrile (ATS)-was selected. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and squarewave voltammetry (SWV) methods were used to determine the redox characteristics of organoselenium and organosulfur compounds. The antiradical activity and capacity of the studied compounds were also measured by using stable radical 2,2'-diphenyl-1-picrylhydrazyl (DPPH).

Antioxidant and electron donating function of hypothalamic polypeptides: galarmin and Gx-NH2.

Chemical mechanisms of antioxidant and electron donating function of the hypothalamic proline-rich polypeptides have been clarified on the molecular level. The antioxidant-chelating property of Galarmin and Gx-NH(2) was established by their capability to inhibit copper(II) dichloride catalyzed H(2)O(2) decomposition, thus preventing formation of HO(*) and HOO(*) radicals. The antiradical activity of Galarmin and Gx-NH(2) was determined by their ability to react with 2,2-diphenyl-1-picrylhydrazyl radical applying differential pulse voltammetry and UV-Vis spectrophotometry methods.

Numerical revelation of the kinetic significance of individual steps in the reaction mechanism of methyl linoleate peroxidation inhibited by alpha-tocopherol.

A kinetic model was constructed to describe the reactions involved in the oxidation of methyl linoleate (ML) inhibited by alpha-tocopherol (TH). The initial model of the reaction mechanism included 53 individual steps, which were numerically analyzed by the value method based on Hamiltonian systematization of kinetic equations. Good accord was obtained with experimental data at 40 and 50 degrees C.

Differential pulse voltammetric studies of ethidium bromide binding to DNA.

The interaction of ethidium bromide (EtBr) with calf thymus DNA is investigated electrochemically with the use of differential pulse voltammetry (DPV) at two different ionic strengths of a solution (0.154 M and 0.02 M [Na+], pH 7.