Prooxidative activities of 10 phenazine derivatives relative to that of clofazimine

The objective of this study was to investigate the relationship between the antimycobacterial properties of the antileprosy drug clofazimine and its stimulatory effect on the release of reactive oxidants by polymorphonuclear leukocytes by using a variety of phenazine derivatives. The effects of these compounds on myeloperoxidase-mediated iodination, luminol-enhanced chemiluminescence, and the release of superoxide anion by polymorphonuclear leukocytes were investigated. Dissociation of the antimycobacterial and prooxidative effects of clofazimine was possible by manipulation of the chemical group in position 2 of the phenazine molecule. When nitrogen-containing substituents in this position were replaced by oxygen, the mode of the prooxidative action of the compounds was altered.