Design, synthesis and evaluation of coumarin-pargyline hybrids as novel dual inhibitors of monoamine oxidases and amyloid- β aggregation for the treatment of Alzheimer's disease

A series of coumarin-pargyline hybrids (4a-x) have been designed, synthesized and evaluated as novel dual inhibitors of Alzheimer's disease (AD). Most of the compounds exhibited a potent ability to inhibit amyloid-β (Aβ) aggregation and monoamine oxidases. In particular, compound 4x exhibited remarkable inhibitory activities against monoamine oxidases (IC50, 0.027 ± 0.004 μM for MAO-B; 3.275 ± 0.040 μM for MAO-A) and Aβ1-42 aggregation (54.0 ± 1.1%, 25 μM). Moreover, compound 4x showed low toxicity according to in vitro cell toxicity test. The results of the parallel artificial membrane permeability assay for blood-brain barrier indicated that compound 4x would be potent to cross the blood-brain barrier. Collectively, these findings demonstrate that compound 4x was an effective and promising candidate for AD therapy.