(S)-N-Benzyl-1-phenyl-3,4-dihydroisoqunoline-2(1H)-carboxamide Derivatives, Multi-Target Inhibitors of Monoamine Oxidase and Cholinesterase: Design, Synthesis, and Biological Activity

Quinoline-sulfonamides as a multi-targeting neurotherapeutic for cognitive decline: in vitro, in silico studies and ADME evaluation of monoamine oxidases and cholinesterases inhibitors

Alzheimer's disease (AD) is a multifactorial irreversible neurological disorder with multiple enzymes involved. In the treatment of AD, multifunctional agents targeting cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors have shown promising results. Herein, a series of novel quinoline-sulfonamides (a1-18) were designed and synthesized as a dual inhibitor of MAOs and ChEs. The in vitro results showed that compounds a5, a12, a11, and a6 exhibited the most potent compounds against specific enzymes. They had IC50 value 0.59 ± 0.04 for MAO-A, 0.47 ± 0.03 for MAO-B, 0.58 ± 0.05 for BChE and 1.10 ± 0.77 for AChE μM respectively. Furthermore, kinetic studies revealed that these compounds are competitive. Molecular docking studies enhanced the understanding of the in silico component, unveiling critical interactions, specifically the hydrogen bonding interaction, π-π, π-alkyl, π-amid and π-sulfur interactions between the ligand and enzymes. These findings suggest that compounds a5, a6, a11, a12, a15, and a18 may be potent multifunctional candidates for AD treatment.

Benzothiazole-Propanamide Linker Pyrrolidine (Morpholine) as Monoamine Oxidase-B and Butyrylcholinesterase Inhibitors

According to the fusion technique create effective multi-target-directed ligands, in this study, we designed and synthesized a series of benzo[d]thiazol-2-yl)-3-(pyrrolidin-1-yl) or 3-(morph- olino-1-yl)propanamide derivatives, and evaluated their inhibitory potency against MAOs, AChE, BuChE by in vitro enzyme effect assays. Based on activity results, we found that derivatives N-(5-methylbenzo[d]thiazol-2-yl)-3-(pyrrolidin-1-yl)propanamide (2 c) and N-(6-bromobenzo[d]thiazol-2-yl)-3-(pyrrolidin-1-yl)propanamide (2 h) showed good inhibitory potency against BuChE with IC50 values of 15.12 μM and 12.33 μM, respectively. Besides, 2 c and 2 h also exhibited selective MAO-B inhibitory effects with inhibition rates of 60.10 % and 66.30 % at 100 μM, respectively. In contrast, all designed derivatives were poor active against AChE and MAO-A at a concentration of 100 μM. The toxicity analysis in vitro by MTT and AO/EB fluorescence staining confirmed that 2 c and 2 h were nontoxic up to 100 μM. Molecular modeling studies showed that 2 c and 2 h could bind to the active site of BuChE. This research paves the way for further study aimed at designing MAO-B and BuChE inhibitors for the treatment of neurodegenerative disorders.