Mühendislik ve Doğa Bilimleri Fakültesi

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Citation Count: 5
Design, Synthesis and hMAO Inhibitory Screening of Novel 2-Pyrazoline Analogues
(Bentham Science Publ Ltd, 2017) Yelekçi, Kemal; Uçar, Gülberk; Yelekçi, Kemal
Aim and Objective: MAO inhibitors have a significant effect on the nervous system since they act in regulation of neurotransmitter concentrations. Neurotransmitter levels are critical for a healthy nervous system. MAO inhibitors can be used in the treatment of neurological disorders such as depression, Parkinson's disease and Alzheimer's disease, as the increase or decrease of some neurotransmitter concentrations is associated with these neurological disorders. This study was conducted to discover new and active MAO inhibitor drug candidates. Materials and Methods: New pyrazoline derivatives have been designed with the molecular docking approach and interactions of our compounds with the MAO enzyme have been investigated using the Autodock 4.2 program. The designed pyrazoline derivative compounds were synthesized by the reaction of the chalcones and hydrazides in ethanol. hMAO inhibitory activities of the newly synthesized compounds were investigated by fluorimetric method. In vitro cytotoxicity of five most potent inhibitors were tested in HepG2 cells. Results: (3-(5-bromo-2-hydroxyphenyl)-5-(4-methoxyphenyl)-4,5-dihydropyrazol-1-yl)(phenyl) methanone (5i) and (3-(2-hydroxy-4-methoxy phenyl)-5-p-tolyl-4,5-dihydropyrazol-1-yl)(phenyl) methanone (5l) inhibited hMAO-A more potently than moclobemide (Ki values are 0.004 +/- 0.001 and 0.005 +/- 0.001, respectively). The same two compounds, 5i and 5l, inhibited hMAO-A more selectively than moclobemide (SI values are 5.55x10(-5) and 0.003, respectively). Both of these compounds were found non toxic at 1 mu M, 5 mu M and 25 mu M concentrations. Conclusion: Two of the newly synthesized compounds, (3-(5-bromo-2-hydroxyphenyl)-5-(4-methoxyphenyl)- 4,5-dihydropyrazol-1-yl)(phenyl) methanone and (3-(2-hydroxy-4-methoxy phenyl)5- p-tolyl-4,5-dihydropyrazol-1-yl)(phenyl) methanone were found to be promising MAO-A inhibitors due to their high inhibitory potency, high selectivity and low toxicity.
Citation Count: 11
Evaluation of selective human MAO inhibitory activities of some novel pyrazoline derivatives
(SPRINGER WIEN, 2013) Yelekçi, Kemal; Yabanoglu-Ciftci, Samiye; Ercan, Ayse; Yelekçi, Kemal; Ucar, Gulberk; Gokhan-Kelekçi, Nesrin
A series of 1-[2-((5-methyl/chloro)-2-benzoxazolinone-3-yl)acetyl]-35-diaryl-45-dihydro-1H-pyrazole derivatives were prepared by reacting 2-((5-methyl/chloro)-2-benzoxazolinone-3-yl)acetylhydrazine with appropriate chalcones. The chemical structures of all compounds were confirmed by elemental analyses IR H-1 NMR and ESI-MS. All the compounds were investigated for their ability to selectively inhibit monoamine oxidase (MAO) by in vitro tests. MAO activities of the compounds were compared with moclobemide and selegiline and all the compounds were found to inhibit human MAO-A selectively. The inhibition profile was found to be competitive and reversible for all compounds by in vitro tests. Among the compounds examined compounds 5ae 5af and 5ag were more selective than moclobemide with respect to the K (i) values experimentally found. In addition the compound 5bg showed MAO-A inhibitor activity as well as moclobemide. A series of experimentally tested compounds (5ae-5ch) were docked computationally to the active site of the MAO-A and MAO-B isoenzyme. The AUTODOCK 4.01 program was employed to perform automated molecular docking.
Citation Count: 123
New pyrazoline bearing 4(3H)-quinazolinone inhibitors of monoamine oxidase: Synthesis biological evaluation and structural determinants of MAO-A and MAO-B selectivity
(Pergamon-Elsevier Science Ltd, 2009) Yelekçi, Kemal; Koyunoğlu, Semra; Yabanoğlu-Çiftçi, Samiye; Yelekçi, Kemal; Özgen, Özen; Uçar, Gülberk; Erol, Kevser; Kendi, Engin; Yeşilada, Akguel; Yelekçi, Kemal
A new series of pyrazoline derivatives were prepared starting from a quinazolinone ring and evaluated for antidepressant anxiogenic and MAO-A and -B inhibitory activities by in vivo and in vitro tests respectively. Most of the synthesized compounds showed high activity against both the MAO-A (compounds 4a-4h 4j-4n and 5g-5l) and the MAO-B (compounds 4i and 5a-5f) isoforms. However none of the novel compounds showed antidepressant activity except for 4b. The reason for such biological properties was investigated by computational methods using recently published crystallographic models of MAO-A and MAO-B. The differences in the intermolecular hydrophobic and H-bonding of ligands to the active site of each MAO isoform were correlated to their biological data. Compounds 4i 4k 5e 5i and 5l were chosen for their ability to reversibly inhibit MAO-B and MAO-A and the availability of experimental inhibition data. Observation of the docked positions of these ligands revealed interactions with many residues previously reported to have an effect on the inhibition of the enzyme. Among the pyrazoline derivatives it appears that the binding interactions for this class of compounds are mostly hydrophobic. All have potential edge-to-face hydrophobic interactions with F343 as well as pi-pi stacking with Y398 and other hydrophobic interactions with L171. Strong hydrophobic and H-bonding interactions in the MAO recognition of 4i could be the reason why this compound shows selectivity toward the MAO-B isoform. The very high MAO-B selectivity for 4i can be also explained in terms of the distance between the FAD and the compound which was greater in the complex of MAO-A-4i as compared to the corresponding MAO-B complex. (C) 2008 Elsevier Ltd. All rights reserved.
Citation Count: 20
Synthesis and Screening of Human Monoamine Oxidase-A Inhibitor Effect of New 2-Pyrazoline and Hydrazone Derivatives
(Wiley-VCH Verlag GmbH, 2015) Yelekçi, Kemal; Baysal, İpek; Yabanoğlu-Çiftçi, Samiye; Djikic, Teodora; Yelekçi, Kemal; Uçar, Gülberk; Ertan, Rahmiye
A group of 35-diaryl-2-pyrazoline and hydrazone derivatives was prepared via the reaction of various chalcones with hydrazide compounds in ethanol. Twenty original compounds were synthesized. Ten of these original compounds have a pyrazoline structure nine of these original compounds have a hydrazone structure and one of these original compounds has a chalcone structure. Structural elucidation of the compounds was performed by IR H-1 NMR C-13 NMR mass spectral data and elemental analyses. These compounds were tested for their inhibitory activities toward the A and B isoforms of human monoamine oxidase (MAO). Except for 3k and 6c all compounds were found to be competitive reversible and selective inhibitors for either one of the isoforms (hMAO-A or MAO-B). Compounds 3k and 6c were found to be competitive reversible but non-selective MAO inhibitors. Compound 6h showed hMAO-B inhibitory activity whereas the others potently inhibited hMAO-A. Compound 5c showed higher selectivity than the standard drug moclobemide. According to the experimental K-i values compounds 6i 6d and 6a exhibited the highest inhibitory activity toward hMAO-A. The AutoDock 4.2 program was employed to perform automated molecular docking. The calculated results obtained computationally were in good agreement with the experimental values.
Citation Count: 47
Synthesis of some novel hydrazone and 2-pyrazoline derivatives: Monoamine oxidase inhibitory activities and docking studies
(Pergamon-Elsevier Science Ltd, 2014) Yelekçi, Kemal; Yabanoglu-Ciftci, Samiye; Ucar, Gulberk; Yelekçi, Kemal; Ertan, Rahmiye
A novel series of 2-pyrazoline and hydrazone derivatives were synthesized and investigated for their human monoamine oxidase (hMAO) inhibitory activity. All compounds inhibited the hMAO isoforms (MAO-A or MAO-B) competitively and reversibly. With the exception of 5i which was a selective MAO-B inhibitor all derivatives inhibited hMAO-A potently and selectively. According to the experimental K-i values compounds 6e and 6h exhibited the highest inhibitory activity towards the hMAO-A whereas compound 5j which carries a bromine atom at R-4 of the A ring of the pyrazoline appeared to be the most selective MAO-A inhibitor. Tested compounds were docked computationally into the active site of the hMAO-A and hMAO-B isozymes. The computationally obtained results were in good agreement with the corresponding experimental values. (C) 2014 Elsevier Ltd. All rights reserved.

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