Abstract
The inhibitory actions of azelastine hydrochloride (AZ) and AA-861 against 5-lipoxygenase were examined and compared with that of gossypol acetic acid (GAA) by measuring the calcium ionophorestimmulated synthesis of LTB4 in human polymorphonuclear calls (PMN) and rat pulmonary-lavaged cells, most of which were macrophages. Fifty percent inhibition of LTB4-synthesis (IC50) was obtained with GAA at 2.4×10-6M in human PMN and rat pulmonary lavaged cells. The IC50 of AZ was 2.6×10-5M in PMN and 2.1×10-5M in rat pulmonary lavaged cells. It is aboutone tenth as potent as GAA.
The IC50 of AA-861 was 2.3×10-6M in human PMN and 0.67×10-7M in pulmonary lavaged cells. The potency of inhibition was equal to that of GAA in human PMN and 35.8 times as strong as that of GAA in pulmonary lavaged cells.
