Zileuton

Zileuton 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) .