2-[(3-chlorophenyl)methyl]-5-hydroxy-1H-benz[g]indole-3-carboxylic acid, ethyl ester

5-Lipoxygenase (5-LO) initiates the synthesis of leukotrienes (LTs) from arachidonic acid, primarily in certain leukocyte populations. A potent, reversible inhibitor of 5-LO, both in cell-free assays (IC₅₀ = 86 nM) and in intact neutrophils (IC₅₀ = 230 nM). It prevents the production of LTs in whole blood, whether 5-LO is activated with the calcium ionophore A23187 (IC₅₀ = 1.6 μM) or formyl peptide (fMLP) following priming with lipopolysaccharide (IC₅₀ = 830 nM). In rats subjected to carrageenan-induced pleurisy, CAY10606 significantly reduces both LT biosynthesis and the inflammatory reaction.