The superoxide radical O2.-, whether produced by the xanthine/xanthine oxidase reaction or infused as KO2, solubilized by a crown ether in dry dimethyl sulphoxide, initiated a free-radical chain oxidation of anionic 2-nitropropane. Superoxide dismutase, but not catalase, inhibited oxidation of the nitroalkane. Xanthine oxidase suffered a syncatalytic inactivation, during the co-oxidation of 2-n...

Free radicals are atoms or molecules containing one or more unpaired electrons, making them very “reactive” (Surai, 2003). Biologically relevant free radicals are activated atoms or groups of atoms (usually containing oxygen or nitrogen) with an odd (unpaired) number of electrons. In a non-radical compound, all orbits are occupied by two electrons. When a chemical reaction breaks the bonds that...

Riboflavin (RF) upon irradiation with fluorescent light generates reactive oxygen species like superoxide anion, singlet and triplet oxygen, flavin radicals and substantial amounts of hydrogen peroxide (H2O2). H2O2 can freely penetrate cell membrane and react with a transition metal ion like Cu(ll), generating hydroxyl radical via the modified metal-catalyzed Haber-Weiss reaction. Earlier, it w...

The intramolecular radical addition to aniline derivatives was investigated by DFT calculations. The computational methods were benchmarked by comparing the calculated values of the rate constant for the 5-exo cyclization of the hexenyl radical with the experimental values. The dispersion-corrected PW6B95-D3 functional provided very good results with deviations for the free activation barrier c...

In this study, we discover unexpectedly that simple reaction of AgNO3 with oleic acid (OA) without solvent and surfactant could generate alkyl free radical which can catalyze double-bond polymerization of OA to form 1D polymeric oleic acid (POA) chain. In certain conditions, these POA chains circumvolute tightly each other to form microspheres and micro-plates in which monodisperse 4-5 nm Ag na...

The radical carbohydroxylation of styrenes with aryldiazonium salts has been achieved under mild thermal conditions. A broad range of aryldiazonium salts was tolerated, and the reaction principle based on a radical-polar crossover mechanism could be extended to carboetherification as well as to a two-step, metal-free variant of the Meerwein arylation leading to stilbenes.

Herein, we report an advancement in the application of visible light photoredox catalysts in a classic free radical mediated reaction, cyclization onto unactivated pi-systems. The reactive radical intermediate is generated by the single electron reduction of an activated C-Br bond by an electron-rich redox catalyst afforded by a visible light induced catalytic cycle.

Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield num...

The reaction of 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) with active species of oxygen (hydrogen peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, sodium peroxide, potassium superoxide, hydroxyl radical, tempo free radical, galvinoxyl free radical, Fremy’s salt, mchloroperbenzoic acid, potassium hydroxide, and sodium peroxynitrite) was reviewed and the new obtained results compa...

The root of ginseng, Panax ginseng, has been heat-processed to improve its medicinal efficacy in Korea. Ginsenosides have been regarded as the main active components responsible for the pharmacological activities of ginseng. Although the Maillard reaction is known as a major source of compounds related to enhanced antioxidant activity by heat treatment in various crude drugs or foods, the chemi...