Discovery and Biological Evaluation of a Novel Class of Dual Microsomal Prostaglandin E2 Synthase-1/5-lipoxygenase Inhibitors Based on 2-[(4,6-Diphenethoxypyrimidin-2-yl-)thio]hexanoic Acid

Various inflammatory diseases are associated with the excessive formation of leukotrienes (LTs) and prostaglandins (PGs). Herein, we present a novel class of dual inhibitors of 5-lipoxygenase (5-LO) and microsomal prostaglandin E-2 synthase-1 (mPGES-1), key enzymes in the formation of LTs and PGE(2), respectively. On the basis of the structure of 2-[(4,6-diphenethoxypyrimidin-2-yl-)thio]hexanoic acid (1), we performed a detailed SAR analysis, and mechanistic studies were carried out to elucidate the mode of 5-LO inhibition. Interestingly, the pyrimidine ring including the thioether of 1 could be replaced by a simple benzyl or a benzylidene moiety yielding a novel series of bioactive 2-benzylidene- and 2-benzylhexanoic acids exemplified by 2-(2,3-diphenethoxybenzylidene)hexanoic acid, 29 (IC50 5-LO = 0.8 mu M; mPGES-1 = 1.1 mu M). Importantly, none of the novel bioactive derivatives strongly inhibited cyclooxygenase activities. Together, we provide novel promising lead compounds for the treatment of inflammatory diseases valuable for further investigations in vivo.