Inhibition of amine oxidases activity by 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives

A novel series of 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives have been synthesised and investigated for the ability to inhibit selectively monoamine oxidases, swine kidney oxidase, and bovine serum amine oxidase. The newly synthesised compounds 1–6 proved to be reversible and non-competitive inhibitors of all types of the assayed amine oxidases. Compounds inhibit monoamine oxidases potently, displaying low I50 values of particular interest. In particular 1-acetyl-3-(2,4-dihydroxyphenyl)-5-(3-methylphenyl)-4,5-dihydro-(1H)-pyrazole 6 showed to be a potent monoamine oxidase inhibitor with a Ki of about 10−8 M. Further insights in the theoretical evaluation of the possible interactions between the compounds and monoamine oxidase B have been developed through a computational approach.