Hydroxyl radical formation by dithranol

Area of Science:

• Biochemistry
• Pharmacology
• Free Radical Chemistry

Background:

• Antipsoriatic drugs can generate reactive oxygen species.
• Understanding drug-induced radical formation is crucial for safety and efficacy.

Purpose of the Study:

• To investigate hydroxyl radical generation by the antipsoriatic drug dithranol.
• To elucidate the mechanism of dithranol-induced radical formation.

Main Methods:

• Ethene formation assay using 2-keto-thiomethyl-butyric acid (KMBA) as a substrate.
• Experiments conducted in phosphate buffer (pH 7.8) under aerobic and dark conditions.
• Inhibition studies using various scavengers and enzymes (catalase, superoxide dismutase).

Main Results:

• Dithranol induced ethene formation from KMBA, indicating hydroxyl radical generation.
• Ethene formation was oxygen-dependent and enhanced by FeCl3, suggesting a superoxide-driven Fenton reaction.
• Inhibition of ethene formation by scavengers and enzymes confirmed the involvement of superoxide and hydroxyl radicals.

Conclusions:

• Dithranol generates hydroxyl radicals through a superoxide-driven Fenton-like reaction.
• The study provides evidence for the role of reactive oxygen species in dithranol's mechanism of action or potential toxicity.