Using ESR we have demonstrated the formation of the ascorbate free radical from sodium ascorbate, methylene blue and light. In oxygen uptake experiments we have observed the production of hydrogen peroxide while spin trapping experiments have revealed the iron catalyzed production of the hydroxyl free radical in this system. The presence of this highly reactive radical suggests that it could be...

This study demonstrated that the bacteria could adsorb Fe(3+) and reduce Fe(3+) to Fe(2+). Iron had significant bacteriostatic effects, which were directly proportional to the iron concentration and under the influence of pH and chelator. It presumed that the inhibition of Fe(3+) acts through the formation of hydroxyl free radicals.

Direct evidence for the formation of 1-hydroxylethyl radicals by ultrasound in red wine and air-saturated model wine is presented in this paper. Free radicals are thought to be the key intermediates in the ultrasound processing of wine, but their nature has not been established yet. Electron paramagnetic resonance (EPR) spin trapping with 5,5-dimethyl-l-pyrrolin N-oxide (DMPO) was used for the ...

Site-specific DNA damage by Cu(II) plus H2O2 was investigated by a DNA-sequencing technique. Cu(II) plus H2O2 induced strong DNA cleavage even without piperidine treatment. Piperidine-labile sites were induced frequently at thymine and guanine residues and rarely at adenine residue. A Cu(I)-specific chelating agent, bathocuproine, inhibited the DNA damage. Neither ethanol nor mannitol inhibited...

Different studies have demonstrated that the bioactivity of hydroxyflavones is due to their antioxidant and free radical scavenging activity. Recently, most interest has been devoted to structure-activity relationships; however, the main problems encountered in these studies are the low solubility of some hydroxyflavones in aqueous solution and the pro-oxidant character of the hydroxyl group at...

Argentine croaker (Umbrina canosai) and chicken (Gallus domesticus) bones were hydrolyzed with different proteases (Flavourzyme, "-Chymotrypsin and Trypsin) in order to obtain peptides whit antioxidant activity. The hydrolysates showed different degrees of hydrolysis and antioxidant activity. The antioxidant power of the hydrolysates was evaluated through inhibition of the peroxidation of linol...

We have recently shown that increased hydrogen peroxide (H2O2) generation is involved in hypoxia-ischemia (HI)-mediated neonatal brain injury. H2O2 can react with free iron to form the hydroxyl radical, through Fenton Chemistry. Thus, the objective of this study was to determine if there was a role for the hydroxyl radical in neonatal HI brain injury and to elucidate the underlying mechanisms. ...

Hematoporphyrin derivative, used in photodynamic therapy of cancer, was found to generate the cysteinyl free radical as seen by spin-trapping. Oxygen appears to be an absolute requirement for thiyl radical production. Singlet oxygen may be the initiating species since azide inhibits oxygen uptake and radical production. In addition, the hydroxyl radical, or a radical with similar reactivity, is...

background: alpinia galanga l. belonging to the family zingiberaceae is widely grown in the state of kerala, india. they are effective antioxidant and free radical scavenger under both in vitro and in vivo condition. the efficacy of the isolated flavonoids in conferring protection from radiation induced damages to genomic dna was studied. materials and methods: the bioflavonoids, galangin and k...