Oxidation-reduction properties of methylglyoxal-modified protein in relation to free radical generation were investigated. Glycation of bovine serum albumin by methylglyoxal generated the protein-bound free radical, probably the cation radical of the cross-linked Schiff base, as observed in the reaction of methylglyoxal with L-alanine (Yim, H.-S., Kang, S.-O., Hah, Y. C., Chock, P. B., and Yim,...

Drugs based on nitroarene, aromatic N-oxide or quinone structures are frequently reduced by cellular reductases to toxic products. Reduction often involves free radicals as intermediates which react rapidly with oxygen to form superoxide radicals, inhibiting drug reduction. The elevation of cellular oxidative stress accompanying oxygen inhibition of reduction is generally less damaging than dru...

Elemental and gaseous oxygen presents a conundrum in that it is simultaneously essential for and potentially destructive to human life. Traditionally the ability to consume large volumes of oxygen has been assumed to be totally beneficial to the organism. In the past 10 years it has become clear that oxygen radicals are generated even during normal resting metabolism. Nevertheless, such radical...

The neurotransmitter analogue 6-hydroxydopamine has been proposed as a selective chemotherapeutic agent for peripheral neural crest tumors. It exerts its action through the generation of cytotoxic oxygen free radicals. Unfortunately, it is toxic to normal peripheral neurons as well. Ethiofos (WR-2721) is a free radical scavenger which appears to be preferentially taken up by normal cells relati...

We recently published electron paramagnetic resonance (EPR) spin trapping results that demonstrated the enzymatic reduction of sulfur mustard sulfonium ions to carbon-based free radicals using an in vitro system containing sulfur mustard, cytochrome P450 reductase, NADPH, and the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) in buffer (A.A. Brimfield et al., 2009, Toxicol. Appl. ...

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...

The cytotoxic effects of ferric nitrilotriacetate (Fe-NTA) have been considered to be caused by free radicals produced by the drug. The present study was carried out to determine whether or not cytotoxic effects of Fe-NTA on cell growth and lipoperoxide formation of Chinese hamster cells were reduced by antioxidants. Using a spin trapping technique, we found that hydroxyl radical formation in t...

There has been considerable controversy regarding the role of oxygen free radicals as important mediators of cell damage in reperfused myocardium. This controversy regards whether superoxide and hydroxyl free radicals are generated on reperfusion and if these radicals actually cause impaired contractile function. In this study, EPR studies using the spin trap 5,5-dimethyl-1-pyroline-n-oxide (DM...

Hematoporphyrin is known to have photodynamic properties. The exposure of biomolecules or cells to hematoporphyrin and visible light can result in damage [l] and can even be lethal [2]. This inactivating effect appears to be greater in cancer cells than in corresponding normal cells [3]. This is thought to be due in part to the greater acc~ulation of hematoporphyrin in malignant tissue than in ...