vitamin-k-semiquinone-radical and 10-10--dimethyl-9-9--biacridinium

Benzophenone is an ultraviolet (UV)-absorbing agent that has been used in industry and medicine for more than 30 years. Consumers of cosmetics and sunscreens containing UV-absorbers are exposed to benzophenones on a daily basis, owing to the widespread use of these compounds. However, the efficacy of these compounds as scavengers of oxidative stress is still not well established. In the present study, we investigate the antioxidative capacity of six sunscreen benzophenone compounds. A primary myoblast culture was mixed in vitro with 100 microM menadione. The cytotoxic effect by menadione-induced oxidative stress was monitored by the lucigenin- or luminol-amplified chemiluminescence, methylthiotetrazole (MTT) assay, and the antioxidative effects of various benzophenone compounds were evaluated. The results showed that the addition of menadione can induce oxidative stress on myoblasts by superoxide and hydrogen peroxide production, which can be eradicated by superoxide dismutase (SOD) and catalase, respectively, in a dose-dependent mode. The catalase has a protective effect on the cytotoxicity induced by menadione as measured by the MTT assay, while the SOD does not. The selected benzophenones also have a significant scavenging effect on the menadione-induced cell death on the myoblasts. The ortho-dihydroxyl structure and other hydroxy groups in the same ring have a stronger scavenging effect on the superoxide anion on myoblasts; thus, a stable penoxy radical may be formed. The mechanism of this effect remains to be clarified.

Topics: Acridines; Animals; Benzophenones; Cell Survival; Drug Evaluation, Preclinical; Free Radical Scavengers; Humans; In Vitro Techniques; Luminescent Measurements; Luminol; Muscle, Skeletal; Oxidative Stress; Rats; Sunscreening Agents; Superoxide Dismutase; Tetrazolium Salts; Thiazoles; Vitamin K

Oxygen-derived free radical injury has been associated with several cytopathic conditions. Oxygen radicals produced by chondrocytes is an important mechanism by which chondrocytes induce matrix degradation. In the present study, we extend these observations by studying oxidative processes against osteoblasts. Osteoblasts were mixed in in vitro culture with 200 microM menadione. The cytotoxic effect of menadione-induced oxidative stress was monitored by lucigenin- or luminol-amplified chemiluminescence, tetrazolium assay and immunocytochemical study. Results showed that adding menadione induces an oxidative stress on osteoblasts, via superoxide and hydrogen peroxide production, that can be eradicated by superoxide dismutase (SOD) and catalase in a dose-dependent manner. Catalase and the appropriate concentration of dimethyl sulfoxide have a protective effect on cytotoxicity induced by menadione, whereas SOD does not. Menadione-treated osteoblasts have a strong affinity for annexin V, and the nuclei are strongly stained by TUNEL (TdT-mediated dUTP nick-end labelling). The results suggest that menadione-triggered production of reactive oxygen species leads to apoptosis of osteoblasts.

Topics: Acridines; Animals; Apoptosis; Cell Membrane; Cell Survival; Cells, Cultured; DNA Fragmentation; Free Radicals; Lipid Peroxides; Luminol; Membrane Lipids; Osteoblasts; Rats; Rats, Wistar; Skull; Vitamin K

The effects of "pro-oxidant" quinones, doxorubicin, Fe(3+)-ADP-doxorubicin complex, and menadione, as well as of free radical scavengers possessing superoxide-dismuting activities, Fe(3+)-rutin and Cu(2+)-rutin, on superoxide production and lipid peroxidation in rat liver microsomes have been studied. All quinone compounds efficiently suppressed lucigenin-dependent chemiluminescence produced in NADPH-dependent microsomal lipid peroxidation, but exhibited different effects on cytochrome c reduction: doxorubicin and Fe(3+)-ADP-doxorubicin weakly inhibited and menadione enhanced it. In accord with previous findings, menadione inhibited malondialdehyde (MDA) formation in microsomes, while Fe3-ADP-doxorubicin enhanced it. Efficiency of inhibition of MDA formation by the Fe(3+)-rutin and Cu(2+)-rutin complexes correlated well with their superoxide-dismuting activities in contrast to the findings obtained in nonenzymatic liposomal peroxidation, where the formation of superoxide ion is not expected. On these grounds, we propose that superoxide ion is an obligatory initiation species in microsomal lipid peroxidation; the effects of pro-oxidant quinones on lipid peroxidation depends on their ability to chelate iron ions and not on their redox-cycling activities.

Topics: Acridines; Adenosine Diphosphate; Animals; Cattle; Copper; Doxorubicin; Ferric Compounds; Free Radical Scavengers; Lipid Peroxidation; Luminescent Measurements; Malondialdehyde; Microsomes, Liver; NADP; Quinones; Rats; Rutin; Superoxides; Vitamin K

Addition of oxygen to whole cells of Escherichia coli suspended in the presence of the chemiluminescent probe bis-N-methylacridinium nitrate (lucigenin) resulted in a light emission increase of 200% of control. Addition of air to cells showed a chemiluminescent response far less than the response to oxygen. The redox cycling agents paraquat and menadione, which are known to increase intracellular production of O2- and H2O2, were also found to cause a measurable increase in lucigenin chemiluminescence in E. coli cells when added at concentrations of 1 and 0.1 mM, respectively. The oxygen-induced chemiluminescent response was not suppressed by extracellularly added superoxide dismutase or catalase. Further, the lucigenin-dependent chemiluminescent response of aerobically grown E. coli to oxygen was significantly greater than that of cells grown anaerobically. Heat-killed cells showed no increase in chemiluminescence on the addition of either oxygen, paraquat, or menadione. These results show that lucigenin may be used as a chemiluminescent probe to demonstrate continuous intracellular production of reactive oxygen metabolites in E. coli.

Topics: Acridines; Aerobiosis; Bacterial Proteins; Catalase; Cytochromes; Escherichia coli; Luminescent Measurements; Oxygen; Paraquat; Superoxide Dismutase; Vitamin K