The anti-inflammatory effects of ZLJ-6, a novel dual cyclooxygenase/5-lipoxygenase inhibitor

Compound ZLJ-6 [(Z)-1-methyl-1,5-dihydro-2-amino-5-[4-(mesyl)benzylidene]-4H-imi-dazole-4-one mesilate] is a potent inhibitor of cyclooxygenase (IC50 = 0.73 and 0.31 μM, for cyclooxygenase-1 and cyclooxygenase-2 respectively) in human whole blood. It also inhibited the production of thromboxane B2 and prostaglandin E2 in calcium ionophore A23187-induced human (IC50 = 0.50 μM) and rat whole blood (IC50 = 0.93 μM), and rat peritoneal leukocytes (IC50 = 2.27 μM). ZLJ-6 suppressed the activity of 5-lipoxygenase in the rat basophilic leukemia (RBL-1) cell lysate (IC50 = 0.32 μM) and in intact cells (IC50 = 1.06 μM) and reduced the generation of leukotriene B4 (LTB4) in A23187-stimulated human (IC50 = 1.61 μM) or rat whole blood (IC50 = 0.99 μM), and rat peritoneal leukocytes (IC50 = 2.59 μM). In vivo, ZLJ-6, administered orally, demonstrated potent anti-inflammatory activity in the carrageenin-induced paw oedema model in rats and showed analgesic activity in the acetic acid-induced abdominal construction model in mice. No gastrointestinal ulcers were found with the anti-inflammatory dose (30 mg/kg) in normal rats. These results indicated that ZLJ-6 potently inhibited 5-lipoxygenase and cyclooxygenase, and blocked the production of LTB4, TXB2 and PGE2. Thus ZLJ-6 is an ideal substitute for classical non-steroidal anti-inflammatory therapy.