Studies on lipoxygenase inhibitors. I. MY3-469 (3-methoxytropolone), a potent and selective inhibitor of 12-lipoxygenase, produced by Streptoverticillium hadanonense KY11449.

Streptoverticillium hadanonense KY11449 was found to produce a 12-lipoxygenase inhibitor MY3-469. The compound was purified by chromatography on Diaion HP-10, charcoal, Sephadex LH-20 and crystallization. The chemical structure of MY3-469 was determined to be 3-methoxytropolone on the basis of its physico-chemical properties. The half maximal inhibitory concentration (IC50) of MY3-469 against bovine platelet 12-lipoxygenase was 1.8 X 10(-6)M. The compound did not inhibit bovine platelet cyclooxygenase at 10(-3)M and showed weak inhibition (IC50 2.8 X 10(-4)) against 5-lipoxygenase of rat basophilic leukemia cells. The results indicate that MY3-469 is a potent and selective inhibitor of 12-lipoxygenase.