Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen.

The antioxidant drug ebselen has been widely studied in both laboratories and in clinical trials. The catalytic mechanism by which it destroys hydrogen peroxide via reduction with glutathione or other thiols is complex and has been the subject of considerable debate. During reinvestigations of several key steps, we found that the seleninamide that comprises the first oxidation product of ebselen underwent facile reversible methanolysis to an unstable seleninate ester and two dimeric products.

Comparison of free-radical inhibiting antioxidant properties of carvedilol and its phenolic metabolites.

Carvedilol is a widely prescribed drug for the treatment of heart failure and the prevention of associated ventricular arrhythmias. It has also been reported to function as a biological antioxidant hydrogen atom transfer from its carbazole N-H moiety to chain-propagating radicals. Metabolites of the drug include phenolic derivatives, such as 3-hydroxy-, 4'-hydroxy- and 5'-hydroxycarvedilol, which are also potential antioxidants.