Biologically-significant scavenging of the myeloperoxidase-derived oxidant hypochlorous acid by some anti-inflammatory drugs

Neutrophils contain the enzyme myeloperoxidase, which oxidizes Cl− ions into the powerful oxidant hypochlorous acid (HOCl). HOCl inactivates α1antiprotease, permitting uncontrolled protease activities. Most anti-inflammatory drugs tested are capable of reacting with HOCl, but the reactions seem insufficiently rapid under physiological conditions to protect α1-antiprotease against inactivation by HOCl. However, rapid scavenging of HOC1 might contribute to the anti-inflammatory effects of penicillamine, gold sodium thiomalate, phenylbutazone and primaquine.