title: Antioxidants suitable for use with chemiluminescence to identify oxyradical species.
abstract: From a panel of 24 alleged antioxidants the most suitable antioxidants (AO) for use with chemiluminescence (CL) experiments were determined. Superoxide dismutase (SOD), using luminol as the chemiluminescence probe (Lum-CL), was inhibitory only towards O2*- and not HO* or (1)O2. SOD was thus a suitable antioxidant for O2*-, as was tiron. Tiron had advantages, however, since SOD acted as a pro-oxidant in the presence of H2O2 or H2O2/HO* generators. The two most suitable antioxidants for (1)O2 were diphenylisobenzofuran (DBF) and tryptophan, for both Lum and Lucigenin-CL (Luc-CL). Desferrioxamine, with both Lum and Luc-CL, was a very effective scavenger for HO*, but appeared to be an even more effective scavenger for (1)O2. Cysteamine showed the best discrimination between IC50s when the two (1)O2 generators NaOCl/H2O2 and NDPO2 were compared. Cysteamine was, therefore, the only scavenger that was appropriate for studies with hypochlorite. Melatonin, with Lum-CL, was found to be the most suitable scavenger for HO*. Mannitol, the classical AO for HO*, was not suitable when used with CL since it acted as a pro-oxidant. Some of the AOs revealed either calyx- or bell-shaped CL inhibition profiles and presumably, therefore, may act as both pro- or antioxidants at different concentrations. Antioxidants showing these kinds of dual activities should be used with caution in CL studies.
authors.affiliation: Department of Surgery, University of the Witwatersrand, Parktown, Johannesburg, South Africa. 042MMJ@Chiron.wits.ac.za
authors.forename: M M
authors.initials: MM
authors.lastname: Oosthuizen
authors.forename: D
authors.initials: D
authors.lastname: Greyling
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D017665:Hydroxyl Radical; D006997:Hypochlorous Acid / Q000494:pharmacology; D008163:Luminescent Measurements; D010100:Oxygen / Q000378:metabolism*; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D013481:Superoxides; D017665:Hydroxyl Radical; D006997:Hypochlorous Acid; D013482:Superoxide Dismutase; D010100:Oxygen