Person: DANIŞ, ÖZKAN
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DANIŞ
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ÖZKAN
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Publication Open Access In vitro and in silico investigation of inhibitory activities of 3-arylcoumarins and 3-phenylazo-4-hydroxycoumarin on MAO isoenzymes(2022-11-01) DANIŞ, ÖZKAN; DEMİR, SERAP; ERDEM, SAFİYE; OGAN, AYŞE; Yuce-Dursun B., DANIŞ Ö., Ozalp L., Sahin E., DEMİR S., ERDEM S., OGAN A.A series of 3-aryl coumarin derivatives and 3-phenylazo-4-hydroxycoumarin were evaluated for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity by fluorometric enzymological assays. Among 21 coumarin derivatives, compound 21 (3-phenylazo-4-hydroxycoumarin) displayed a good inhibitory activity (0.12 +/- 0.02 mu M) and very high selectivity for MAO-B (SI > 833.33). The inhibition was determined as mixed-type and not time-dependent. Docking studies, molecular dynamics and molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) calculations were performed to elucidate in vitro results. Our results reveal that the insertion of an azo linker between coumarin and phenyl rings in 3-arylcoumarins enhances MAO-B selectivity enormously since such a linker leads to the perfect alignment of the coumarin ring in the aromatic cage and the phenyl ring in the entrance cavity of MAO-B active site. Hydrogen bond interactions with Cys172 in the active site entrance of MAO-B also contributes to the remarkably higher inhibitory activity and selectivity for MAO-B.Publication Open Access Novel azole-urea hybrids as VEGFR-2 inhibitors: Synthesis, in vitro antiproliferative evaluation and in silico studies(2023-12-15) KULABAŞ, NECLA; DANIŞ, ÖZKAN; KÜÇÜKGÜZEL, İLKAY; Shirzad M. M., KULABAŞ N., Erdoğan Ö., Çevik Ö., Dere D., Yelekçi K., DANIŞ Ö., Küçükgüzel İ.The vascular endothelial growth factor receptor-2 (VEGFR-2) is a receptor tyrosine kinase known to be abnormally expressed in various malignant tumors, including breast cancer, and is considered one of the most important contributors to tumor angiogenesis. Sorafenib is one of many VEGFR-2 inhibitors that have received approval for clinical use from the US FDA in recent years. Accordingly, in this study, the synthesis of two new pyrazoles, six 1,3,4-oxadiazoles, four 1,3,4-thiadiazoles, and ten 1,2,4-triazole-3-thione derivatives having structural characteristics similar to sorafenib was carried out. A preliminary screening of synthesized compounds and known inhibitors sorafenib and staurosporine at 10 µM concentration on in vitro activity of VEGFR-2 was performed, and compounds 10c, 8a, and 11 g were identified as the most potent derivatives with% VEGFR-2 residual activities lower than 30%, and dose-dependent inhibition studies was carried out to determine the IC50 values of these inhibitors. Compound 10c was found to be the most potent inhibitor of VEGFR-2 activity with an IC50 value of 0.664 µM. The anti-proliferative activity of synthesized derivatives was assessed against a breast carcinoma (MCF-7) cell line, a triple negative human breast adenocarcinoma (MDA-MB-231) cell line, and noncancerous fibroblast cells (L929). Compound 8a displayed superior activity when compared to sorafenib against MCF-7 (7.69 fold) and MDA-MB-231 (1.52 fold) cell lines while displaying 3.75-fold less toxicity against the normal L929 cell line. Annexin V binding assay revealed that compound 8a significantly increased early and late apoptosis in MCF-7 cells and late apoptosis and necrosis in MDA-MB-231 cells. Computational studies such as molecular docking and ADMET evaluation were performed to elucidate the binding interactions and drug-likeness of the synthesized compounds. The results indicate that compound 8a could be a promising candidate for the development of a novel anti-angiogenic and anti-proliferative agent.Publication Open Access Identification of some novel amide conjugates as potent and gastric sparing anti-inflammatory agents: In vitro, in vivo, in silico studies and drug safety evaluation(2023-08-05) KULABAŞ, NECLA; DANIŞ, ÖZKAN; OGAN, AYŞE; ERDEM, SAFİYE; KÜÇÜKGÜZEL, İLKAY; KULABAŞ N., Set İ., Aktay G., GÜRSOY Ş., DANIŞ Ö., OGAN A., Sağ Erdem S., Erzincan P., Helvacıoğlu S., Hamitoğlu M., et al.Today, usage of NSAIDs (nonsteroidal anti-inflammatory drugs) is very common. However, it has been proven by many studies that NSAIDs with free carboxylic acid group damage the GI (gastrointestinal) system. Our aim was to mask the acidic groups of NSAIDs to prevent or reduce their side effects while preserving their pharmacological effects. In this study, new amide derivatives of known NSAIDs, compounds 11–20, were synthesized to investigate their analgesic and anti-inflammatory effects using in vivo models. While compound 11 showed the most remarkable anti-inflammatory activity by 60.9% inhibition value at 200 mg/kg dose, compounds 11, 12, 15 and 18 had almost the same analgesic activity to that of acetylsalicylic acid (100 mg/kg) and flurbiprofen (100 mg/kg). In addition, all test compounds used at high dose (200 mg/kg, p.o) did not show any acute toxicity. COX-1 and COX-2 inhibition properties of all compounds were measured by biochemical methods and the interaction of the most active compounds with COX enzymes is elucidated by computer-assisted virtual screening methods. It was determined by in vitro enzyme inhibition studies that compound 11 and 13, synthesized from selective COX-1 inhibitors dexketoprofen and flurbiprofen, are selective COX-2 inhibitors. Moreover, compounds 11–13 were found to be non-mutagenic according to the mutagenicity assay using Salmonella TA98 and TA100 strains with and without metabolic activation. Finally, the prediction of ADMET profile and drug-likeness properties of compounds 11–20 were examined and the obtained results were evaluated.Publication Open Access Investigation of the Interaction of Monoamine Oxidase (MAO) Inhibitor Biscoumarins with Hemoglobin and Albumin Using Multi-Spectroscopic Techniques and Molecular Docking(2024-01-01) MELETLİ, FURKAN; DANIŞ, ÖZKAN; Mutafoğlu B. S., MELETLİ F., DANIŞ Ö.Coumarin and their derivatives, such as biscoumarins, which are found as active ingredients in a variety of drugs, possess a wide range of biological activities. In this paper, the inhibitory effects of biscoumarin derivatives B1 and B2 on monoamine oxidase (MAO) enzyme activity were studied. Their binding mechanism to bovine serum hemoglobin (BHb) and bovine serum albumin (BSA) was investigated using molecular docking and multi-spectroscopic methods such as absorption, fluorescence, and synchronized fluorescence spectroscopy. The fluorescence quenching processes were analyzed using the Stern-Volmer, Lineweaver-Burk, and Hill methods. In this regard, Stern-Volmer quenching constants (Ksv), Lineweaver-Burk constants (KLB), and binding constants (Ka) were calculated at three temperatures (298, 310 and 322 K). The fluorescence studies showed that the binding of biscoumarins to BHb or BSA was a driven by static quenching. The Ka values of B2 to BHb and BSA (2179.11 and 18453.98 x 105 M-1) was larger than B1 at corresponding temperature (62.75 and 599.90 x105 M-1 for BHb and BSA, respectively), which indicates that the affinity of B2 toward the proteins were higher than that of B1. Moreover, thermodynamic parameters explained that hydrogen bonds were the main binding force stabilizing the protein-ligand complexes. Additionally, molecular docking studies have revealed binding energies, ligand efficiency values, and interactions with amino acid residues of proteins. The results of these investigations may be helpful in analyzing drug-protein binding of biscoumarins for potential future applications.Publication Open Access Synthesis and evaluation of antiproliferative and mPGES-1 inhibitory activities of novel carvacrol-triazole conjugates(2022-01-01) KULABAŞ, NECLA; DANIŞ, ÖZKAN; OGAN, AYŞE; Demirbolat İ., KULABAŞ N., Gürboğa M., Özakpınar Ö. B., Çiftçi G., Yelekçi K., Liu J., Jakobsson P., DANIŞ Ö., OGAN A., et al.Some novel triazole-bearing acetamide derivatives 9-26 were synthesized starting from carvacrol. All synthesized compounds were characterized by FTIR, 1H-NMR, 13C-NMR and MS data. In vitro cytotoxic activities of all synthesized molecules against five cancer lines (human breast cancer MCF-7, human lung cancer A549, human prostate cancer PC-3, human chronic myelogenous leukemia K562, human neuroblastoma SH-SY5Y cell lines) were evaluated by MTT assay. Compounds were also tested on mouse embryonic fibroblast cells (NIH/3T3) to determine selectivity. Eighteen target compounds 9-26 were screened for their mPGES-1 and COX-1/2 inhibitory activities. Of these compounds, 26 (KUC16D425) showed the highest mPGES-1 inhibition at 10 µM. This compound has also been observed to induce apoptosis and inhibit cell migration in MCF-7 cells. In silico molecular docking calculations were performed to understand the binding interactions of compounds with target proteins. ADMET predictions were also done to evaluate drug-like properties of the novel compounds.Publication Open Access Design, synthesis and biological evaluation of novel benzocoumarin derivatives as potent inhibitors of MAO-B activity(2024-11-15) MELETLİ, FURKAN; DEMİR, SERAP; DANIŞ, ÖZKAN; MELETLİ F., Gündüz C., Alparslan M. M., ATTAR A., DEMİR S., İskit E., DANIŞ Ö.The continued research of novel reversible inhibitors targeting monoamine oxidase (MAO) B remains crucial for effectively symptomatic treatment of Parkinson\"s disease. In this study we synthesized and evaluated a new series of 3-aryl benzo[g] and benzo[h] coumarin derivatives as MAO-B inhibitors. Compound A6 has been found to display the most potent inhibitory activity and selectivity against the MAO-B isoform (IC50 = 13 nM and SI = >7693.31 respectively). Inhibition mode of A6 on MAO-B was predicted as mixed reversible inhibition with a Ki value of 3.274 nM. Furthermore, in order to elaborate structure–activity relationships, the binding mode of A6 was investigated by molecular docking simulations.