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3,5-Diaryl-4,5-dihydroisoxazoles were synthesized and evaluated as monoamine oxidase (MAO) enzyme inhibitors and iron chelators. All compounds exhibited selective inhibitory activity towards the B isoform of MAO in the nanomolar concentration range. The best performing compound was preliminarily evaluated for its ability to bind iron II and III cations, indicating that neither iron II nor iron III is coordinated. The best compounds racemic mixtures were separated and single enantiomers inhibitory activity evaluated. Furthermore, none of the synthesised compounds exhibited activity towards MAO A. Overall, these data support our hypothesis that 3,5-diaryl-4,5-dihydroisoxazoles are promising scaffolds for the design of neuroprotective agents.

With the aim to identify new, potent and selective monoamine oxidase B (MAO-B) inhibitors, molecular interaction field analysis has been applied to a MAO-B complex with 3-acetyl-2,5-diaryl-2,3-dihydro-1,3,4-oxadiazole chemical structure, known as a privileged scaffold for this target. Several compounds displayed potent in vitro activity, exhibiting IC50 values in the medium to low nanomolar range. The enantiomers of most promising derivatives were separated by enantioselective HPLC and in vitro evaluated. Experimental results, according to theoretical drug design, clearly indicated a key role of the ligand stereochemistry in the target recognition/inhibition. In particular the (R)- enantiomers showed the best activity with respect to the (S)- stereoisomer. Finally, docking experiments coupled to molecular dynamics (MD) simulations, were applied for understanding the putative MAO -B binding modes of the new compounds providing detailed information for further structural optimization., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Monoamine oxidase B (MAO-B) is a promising target for the treatment of neurodegenerative disorders. We report the synthesis and the biological evaluation of halogenated derivatives of 1-aryliden-2-(4-phenylthiazol-2-yl)hydrazines. The fluorinated series shows interesting activity and great selectivity toward the human recombinant MAO-B isoform expressed in baculovirus infected BTI insect cells. The multiple crystal structures alignment of the enzyme highlighted pronounced induced fit (IF) adaptations with respect to bound ligands. Therefore, IF docking (IFD) experiments and molecular dynamic (MD) simulations were carried out to reveal the putative binding mode and to explain the experimentally observed differences in the activity of 1-(aryliden-2-(4-(4-chlorophenyl)thiazol-2-yl)hydrazines. The importance of water molecules within the binding site was also investigated. These are known to play an important role in the binding site cavity and to mediate protein-ligand interactions. Detailed analyses of the trajectories provide insights on the chemical features required for the activity of this scaffold. In particular it was highlighted the importance of fluorine atom interacting with the water close to the cofactor and the influence of steric bulkiness of substituents in the arylidene moiety. Free energy perturbation (FEP) analysis confirmed experimental data. The information we deduced will help to develop novel high-affinity MAO-B inhibitors., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Some differently substituted 3-aryl-4,5-dihydropyrazoles-1-carbothioamides have been synthesised with the aim to investigate their monoamine oxidase inhibitory activity. The chemical structures of the compounds have been characterized by means of their IR, (1)H NMR, (13)C NMR spectroscopic data and elemental analyses. All the active compounds showed a selective activity towards the B isoform of the enzyme, regardless of the substitution on the heterocyclic ring. The inhibition of the enzymatic activity was measured on human recombinant MAO isoforms, expressed in baculovirus infected BTI insect cells. Docking experiments were carried out with the aim to rationalize the mechanism of inhibition of the most active and selective compound., (Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.)

Novel 1-(4-arylthiazol-2-yl)-2-(3-methylcyclohexylidene)hydrazine derivatives have been investigated for their ability to inhibit selectively the activity of the human B isoform of monoamine oxidase. These compounds were obtained as racemates and (R)-enantiomers by a stereoconservative synthetic pattern in high yield and enantiomeric excess. The (S)-enantiomers of the most active derivatives have been separated by enantioselective HPLC. All compounds showed selective activity against hMAO-B with IC(50) ranging between 21.90 and 0.018 microM.

A direct HPLC enantioseparation of three new chiral oxadiazoline derivatives endowed with potential MAO-B inhibitory activity was accomplished on the immobilised Chiralpak IA chiral stationary phase. Multi-mg amounts of enantiomers with high enantiomeric purity (ee> or =98%) were rapidly collected using pure dichloromethane as eluent. The absolute configuration and chiroptical properties of the enantiomers isolated at semipreparative scale were exhaustively determined., (Copyright 2010 Elsevier B.V. All rights reserved.)

A new series of synthetic flavones, thioflavones, and flavanones has been synthesized and evaluated as potential inhibitors of monoamine oxidase isoforms (MAO-A and -B). The most active series is the flavanone one with higher selective inhibitory activity against MAO-B. Some of these flavanones (mainly the most effective) have been separated and tested as single enantiomers. In order to investigate the MAOs recognition of the most active and selective compounds, a molecular modeling study has been performed using available Protein Data Bank (PDB) structures as receptor models for docking experiments., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)