LKY-047, a Decursin derivative, is a potent and selective reversible competitive cytochrome P45022J2 (CYP2J2) inhibitor with an IC 50 of 1.7 μM. LKY-047 is inactive against other human P450s, such as CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A In Vitro LKY-047 is a strong competitive inhibitor of CYP2J2-mediated astemizole O-demethylase and terfenadine hydroxylase activity, with K i values of 0.96 μM and 2.61 μM, respectively. LKY-047 also acted as an uncompetitive inhibitor of CYP2J2-mediated ebastine hydroxylation with a K i value of 3.61 μM. At 20 μM LKY-047 concentration, approximately 20-fold greater than the Ki value, LKY-047 is found to inhibit CYP2J2 by 85.3%, and only slightly affecting the enzyme activities of the other P450s tested. LKY-047 weakly inhibits CYP2D6 enzyme activity (37.2%) at 20 μM concentration. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:CYP2J2 1.7 μM (IC 50 )