Zileuton (111406-87-2) is a reversible inhibitor (IC50 = 500nM RBL-1 cells, 300nM rat PMNL cells) of 5-Lipoxygenase (5-LO).1 It also inhibited leukotriene B4 biosynthesis (IC50's = 400nM rat PMNL, 400nM human PMNL and 900nM human whole blood).1 Zileuton suppressed prostaglandin biosynthesis via interference with arachidonic acid release in macrophages independent of 5-LO inhibition (IC50 = 13 μM PGE2 inhibition in LPS-stimulated whole blood).2 Zileuton was approved by the FDA in 1997 for the treatment of asthma (ZYFLO).
1) Carter et al. (1991), 5-Lipoxygense inhibitory activity of zileuton; J. Pharmacol. Exp. Ther. 256 929
2) Rossi et al. (2010), The 5-lipoxygenase inhibitor, zileuton, suppresses prostaglandin biosynthesis by inhibition of arachidonic acid release in macrophages; Br. J. Pharmacol. 161 555