2-Styrylchromone derivatives as potent and selective monoamine oxidase B inhibitors

A series of eighteen 2-styrylchromone derivatives (see Chart 1 ) were synthesized and evaluated for their monoamine oxidase (MAO) A and B inhibitory activities. Many of the derivatives inhibited MAO-B comparable to pargyline (a positive control), and most of them inhibited MAO-B selectively. Of the eighteen derivatives, compound 9 having methoxy group at R1 and chlorine at R4 showed both the best MAO-B inhibitory activity (IC50 = 17 ± 2.4 nM) and the best MAO-B selectivity (IC50 for MAO-A/IC50 for MAO-B = 1500). The mode of inhibition of compound 9 against MAO-B was competitive and reversible. Quantitative structure–activity relationship (QSAR) analyses of the 2-styrylchromone derivatives were conducted using their pIC50 values with the use of Molecular Operating Environment (MOE) and Dragon, demonstrating that the descriptors of MAO-B inhibitory activity and MAO-B selectivity were 1734 and 121, respectively, that showed significant correlations (P