Hydroxyl radical formation by dithranol.
Ethene formation from 2-keto-thiomethyl-butyric acid (KMBA) was used to measure hydroxyl radical generation from the antipsoriatic drug dithranol in phosphate buffer pH 7.8. Because the singlet oxygen (1O2) sensitizer, rose bengale, showed enlarged production of ethene when irradiated in the presence of KMBA, experiments were performed in the dark in order to avoid 1O2 production by dithranol. KMBA was converted to ethene by dithranol under aerobic conditions, whereas ethene formation was negligible in the absence of oxygen. Addition of catalytic amounts of FeCl3 resulted in increased ethene formation, indicating the catalysis of a superoxide-driven Fenton-reaction. O2- - and .OH-scavengers such as rutin, catechin, dimethyl sulfoxide, mannitol, ethanol, sodium salicylate and propyl gallate as well as catalase and superoxide dismutase inhibited ethene formation.
Müller
K
K
Institute of Pharmacy, Free University of Berlin, Federal Republic of Germany.
Kappus
H
H
D000875:Anthralin; D002087:Butyrates; D055598:Chemical Phenomena; D002621:Chemistry; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides; D017665:Hydroxyl Radical; D013438:Sulfhydryl Compounds
D002087:Butyrates; D006878:Hydroxides; D013438:Sulfhydryl Compounds; D017665:Hydroxyl Radical; C045636:2-keto-4-mercaptobutyric acid; D000875:Anthralin