Accompanying the autoxidation of hydroxylamine at pH 10.2, nitroblue tetrazolium was reduced and nitrite was produced in the presence of EDTA. The rate of at&oxidation was negligible below pH 8.0, but sharply increased with increasing pH. The reduction of nitroblue tetrazolium was inhibited by euperoxide dismutaee, indicating the participation of superoxide anion radical in the autoxidation. Hy...

Excitotoxic neuronal death is mediated in part by NMDA receptor-induced activation of NOX2, an enzyme that produces superoxide and resultant oxidative stress. It is not known, however, whether the superoxide is generated in the intracellular space, producing oxidative stress in the neurons responding to NMDA receptor activation, or in the extracellular space, producing oxidative stress in neigh...

The NADPH oxidase enzyme system is the main source of superoxide anions in phagocytic and vascular cells. NADPH oxidase-dependent superoxide generation has been found to be abnormally enhanced in several chronic diseases. Evidence is accumulating that polyphenols may have the potential to improve cardiovascular health, although the mechanism is not fully established. Consumption of concentrated...

Superoxide dismutase reduces injury in many disease processes, implicating superoxide anion radical (O2-.) as a toxic species in vivo. A critical target of superoxide may be nitric oxide (NO.) produced by endothelium, macrophages, neutrophils, and brain synaptosomes. Superoxide and NO. are known to rapidly react to form the stable peroxynitrite anion (ONOO-). We have shown that peroxynitrite ha...

We investigated whether angiotensin II infusion modulates in vivo the kinin B1 receptor expression and the mechanisms involved in this process. We also evaluated the role of the B1 receptor activation in aorta. Wistar rats received 400 ng/kg per minute of angiotensin II or saline (control rats) infusion during 14 days through an osmotic minipump. To investigate the role of superoxide anion in B...

Aluminum, a non-redox-active metal is, nevertheless, a pro-oxidant both in in vitro preparations and in vivo. It facilitates both superoxide- and iron-driven biological oxidation by mechanisms that remain to be resolved. More than 10 years ago Fridovich and colleagues suggested that the facilitation of superoxide-driven biological oxidation by aluminum was due to an interaction between the meta...

Marine saponins are naturally glycosides compounds which possess important biomedical properties such as anti-cancer, antioxidant and anti-inflammatory. Nevertheless, no systematic studies on the anti-inflammatory potential of brittle star saponin and its underlying mechanisms have been reported. In this study, Ophiocoma erinaceus extracted saponin was investigated for its in vitro anti-inflamm...

ion, hydrogen addition or electron transfer, while superoxide anion reacts via only hydrogen abstraction and electron transfer (Section 1.2) (5). Although, hydrogen peroxide and singlet oxygen are classified as ROS, they are not radicals and do not necessarily interact with tissue through radical reactions directly (6). Hence, they are not toxic per se but in presence of free radicals or cataly...