Superoxide radical scavenging by phenolic bronchodilators under aprotic and aqueous conditions.

Asthmatic airway disease is accompanied by the appearance of inflammatory cells which produce reactive oxygen species (ROS). Therefore, the radical scavenging properties of the bronchodilators reproterol, fenoterol, salbutamol and terbutaline toward superoxide anion radicals and hydroperoxyl radicals were investigated in a model system by electron paramagnetic resonance spectroscopy (EPR) and photometric approaches. The substances under study showed activity in superoxide radical scavenging under aprotic and protic conditions as well.

Antioxidative activity of ginkgolides against superoxide in an aprotic environment.

The terpene lactones ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J and bilobalide, which are components of a standardized extract (EGb 761) from leaves of Ginkgo biloba, as well as ginkgolide M from roots of G. biloba were studied regarding their reaction against superoxide (O2-) and hydroperoxyl radicals (HO2) in dimethyl sulfoxide as an aprotic solvent. It was found that the ginkgolides B, C, J, M as well as bilobalide react with superoxide and its protonated form as demonstrated by EPR and UV/VIS spectroscopy.

Generation of free radicals in Langendorff and working hearts during normoxia, hypoxia, and reoxygenation.

The release of .OH and alkyl free radicals into the coronary flow were compared in Langendorff perfused and working rat hearts during normoxia (30 min), hypoxia (30 min) and reoxygenation (60 min) by means of spin-trapping techniques using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). In Langendorff hearts, there was a small but steady increase in the radical concentration during the course of hypoxia and reoxygenation.

Conformational properties of streptokinase--secondary structure and localization of aromatic amino acids.

The conformational properties of streptokinase (Sk) have been assessed by several spectroscopic techniques. A solvent accessibility of about 70% of the 22 Tyr residues was found by u.v.

Protection of melanoma cells against superoxide radicals by melanins.

Human melanoma cells transplanted into immunocompetent mice by the 6-day subrenal capsule technique are characterized by high resistance against immunological attack. This resistance is suggested to be the consequence of scavenging of superoxide free radicals by melanin. Scavenging of superoxide radicals by the melanoma cells was clearly demonstrated using electron spin resonance techniques.