Metabolic activation of phenols by stimulated neutrophils: a concept for a selective type of anti-inflammatory drug.

Apocynin (4-hydroxy-3-methoxy-acetophenone) is a potent and selective inhibitor of neutrophil oxyradical production. The mechanism of action involves metabolic activation in a (myelo)-peroxidase-dependent reaction. The reaction product(s) prevent(s) the assembly of the superoxide anion-generating NADPH:O2 oxidoreductase by conjugation to essential thiol groups. Different neutrophil functions that are essential to their bactericidal activity, however, remain intact. When administered orally a potent anti-inflammatory activity was found in rats with experimentally induced local or systemic inflammation.