2.6. Monoamine oxidases (MAO-A/-B) inhibition assay

The kynuramine oxidative deamination assay was utilized to evaluate the monoamine oxidases inhibitory effects of compounds 1–4, 7, 9 and 12–14 at concentrations of 0.001–100 μM for MAO-A and 0.01–100 μM for MAO-B (Chaurasiya et al., 2016). The assay is based on tracking and monitoring the MAO catalyzed conversion of kynuramine to 4-hydroxy quinolone fluorometrically. The conditions of the assay were optimized following the previously published procedure (Larit et al., 2018). The oxidized fluorescent product of kynuramine (4-hydroxyquinoline) was assessed at λ_em 380 nm and λ_ex 320 nm following the published procedure using the SoftMax Pro program (Parikh et al., 2002). The standard inhibitors phenelzine, clorgyline, and deprenyl were used at a concentration range of 0.001 μM to 100 μM with the aid of XL-Fit© software.