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    A spectroscopic study on new phthalonitrile derivative and its computational background: 4-[(4,5-Diphenyl-4H-1,2,4-triazol-3-yl)sulfanyl]benzene-phthalonitrile
    (Elsevier, 2017) Akcay, Hakki Turker; Coruh, Ufuk; Bayrak, Riza; Mentese, Emre; Vazquez Lopez, Ezequiel M.
    Heterocyclic phthalonitrile derivatives are important precursors in synthesis of new photoactive phthalocyanine compounds. In this study, novel phthalonitrile compound bearing triazole moiety was synthesized and characterized by using spectroscopic techniques such as FT-IR and NMR. The molecular structures of the title compound was analyzed crystallographically and compared with the structural parameters obtained computationally. The orbital energies, electronic absorptions, atomic charge parameters, vibrational frequencies, ground state transitions, H-1 and C-13 NMR chemical shifts and NBO analysis were computed by using DFT (Density Functional Theory) calculation and compared with the experimental results. (C) 2016 Elsevier B.V. All rights reserved.
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    Evaluation of Antiproliferative Activity and Molecular Modeling Studies of Some Novel Benzimidazolone-Bridged Hybrid Compounds
    (Mdpi, 2025) Guven, Okan; Mentese, Emre; Yilmaz, Fatih; Guner, Adem; Emirik, Mustafa; Caliskan, Nedime
    Background/Objectives: Cancer is among the leading causes of mortality worldwide. In 2022 alone, the global cancer death toll stood at 9.74 million. Projections indicate that this figure will rise to 10.4 million by 2025. Methods: A new series of benzimidazolone-bridged hybrid compounds containing thiophene, furan, oxadiazole, piperazine, and coumarin moieties was synthesized and structurally characterized by 1H-NMR, 13C-NMR (APT), and elemental analysis. Their cytotoxic effects were evaluated by MTT assay against human lung (A549), human breast (MCF-7), and human cervical (HeLa) cancer cell lines, and the non-cancerous HEK293 cell line after 48 h exposure over a concentration range of 0.5-250 mu M. IC50 values were determined, and Selectivity Indexes (SI) were calculated using HEK293 as the reference normal cell line. Molecular docking studies were carried out using the Glide XP protocol against VEGFR2 (PDB ID: 4ASD) and CDK4-Cyclin D3 (PDB ID: 7SJ3), with sorafenib and abemaciclib as reference inhibitors. Results: The results of anticancer activity were compared with doxorubicin (IC50 +/- SD (mu M)/SI: 4.3 +/- 0.2/1.20 for A549, 6.4 +/- 0.37/0.77 for MCF-7, 3.4 +/- 0.19/1.54 for HeLa), a drug used for cancer chemotherapy. The structures of the newly synthesized hybrid compounds were identified by 1H-NMR, 13C-NMR (APT), and elemental analysis data. These hybrid compounds represent a promising class of anticancer agents. Several compounds demonstrated marked and concentration-dependent cytotoxicity across all cancer cell lines, with HeLa cells showing the highest overall sensitivity. The introduction of an oxadiazole ring (compound 7) and coumarin substituents (compounds 12b-12d) markedly improved anticancer activity and selectivity, yielding low-micromolar IC50 values in HeLa cells (10.6-13.6 mu M) and high Selectivity Indexes (SI = 2.0-3.63). Compound 6 also exhibited balanced potency across A549, MCF-7, and HeLa cells (IC50 = 28.3-31.2 mu M) with SI values >= 2.0. Compound 9 showed strong cytotoxicity across all cancer cell lines; its moderate SI values indicate lower discrimination between malignant and non-malignant cells. Taken together, these findings identified compounds 7, 12b-12d, 6, and 12c as the most promising benzimidazolone-based candidates, displaying both potent cytotoxicity and favorable selectivity over non-malignant HEK293 cells. Conclusions: Among the synthesized molecules, the oxadiazole derivative (7) and the coumarin-based hybrids (12b-12d) exhibited the strongest combination of cytotoxic activity and selectivity, reflected by their low IC50 values and high SI ratios. Notably, compound 12c combined strong biological activity with the highest predicted VEGFR2 affinity in the series, highlighting it as a particularly promising scaffold. While compound 9 exhibited excellent docking scores toward both VEGFR2 and CDK4, its lower selectivity suggests a need for further structural refinement. Overall, the biological and computational findings converge to identify these benzimidazolone hybrids as credible lead candidates for future anticancer optimization.
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    Novel Adenine-Hydrazone Hybrids Against Human Lung Adenocarcinoma (A549): Design, Synthesis, Cellular Mechanistic Investigation and Molecular Docking Studies
    (Mdpi, 2026) Mentese, Emre; Caliskan, Nedime; Aksu, Didem; Emirik, Mustafa; Guner, Adem; Yilmaz, Fatih
    Background/Objectives: Adenine derivatives are promising anticancer scaffolds, but their cellular mechanisms remain unclear. This study aimed to synthesize adenine-hydrazone hybrids and evaluate their cytotoxic effects in human lung adenocarcinoma (A549) cells. Methods: A series of adenine-hydrazone compounds (3a-r) was synthesized and tested for cytotoxicity in A549 and MRC-5 cells. Selected compounds were further analyzed for LDH release, oxidative stress markers, ROS production, mitochondrial membrane potential, cell-cycle distribution, apoptosis, and in silico docking against VEGFR2, ALK5, and EGFR. Results: Compounds with electron-withdrawing or donor-acceptor substituents showed the highest cytotoxicity, while halogenated and methoxy analogs were moderately active. Among the synthesized derivatives, 4F-substituted derivatives (3c) showed more activity than 2F- and 3F-substituted ones (3a and 3b). 4F- and 3Br-substituted derivatives (3f) showed more activity than only 4F-substituted ones (3c). 4-Nitro-substituted derivative (3i) showed more activity than 4F- (3c), 4Cl- (3d) and 4OMe- (3h) derivatives. Trimethoxy-substituted derivative (3l) showed more activity than di- and mono-substituted methoxy derivatives (3g, 3h, 3j and 3k). Among the salicyl aldehydederivatives (3m-r), 4-N(et)2-substituted derivative (3r) showed more activity than non-substituted (3m), 5Br-(3n), 5Cl-(3o), 5Me (3p) and 3OCH3 (3q) derivatives. Treatment induced oxidative stress, mitochondrial depolarization, Sub-G1 cell-cycle accumulation, and apoptosis. Docking studies indicated strong binding to VEGFR2 and ALK5, suggesting dual inhibition as a potential mechanism. Conclusions: Adenine-hydrazone derivatives exert substituent-dependent anticancer effects by inducing redox imbalance-associated mitochondrial dysfunction and regulated cell death. These results highlight their potential as lead structures for lung cancer therapy.
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    Novel Coumarin Derivatives Containing a Triazole Moiety: A Study on Synthesis, Cytotoxicity, Membrane Dysfunction, Apoptosis, Cell Cycle, and Antiangiogenic Effects
    (Bentham Science Publ Ltd, 2022) Guner, Adem; Bektas, Hakan; Mentese, Emre
    Background: Coumarin is a functional compound with a pronounced wide range of biological activities and has recently been shown to have anticancer effects on various human cancer cells. Cisplatin is widely used in treating many cancers, but its effectiveness is limited due to acquired resistance and dose-related side effects. Objective: This study aimed to reveal the chemosensitizing ability of novel synthesized coumarin-triazole hybrid compounds (3a-f) compared to the cisplatin in A549, MCF-7, and HeLa cancer cells. Methods: Cytotoxicity was determined by MTT assay. Lactate dehydrogenase (LDH), antioxidant/oxidant status, and DNA fragmentation were determined spectrophotometrically using commercial kits. Muse (TM) Cell Analyzer was used to assess cell cycle progression. Pro/anti-apoptotic gene expressions were determined by Real-Time qPCR. The antiangiogenic activity was determined by VEGF expression and Hen's chorioallantoic membrane model. Results: Compounds 3c, -d, -e, and -f potentiated the cisplatin-induced cytotoxicity by increasing LDH release and DNA fragmentation, inducing G2/M cell cycle arrest, overproducing oxidative stress, and decreasing cellular antioxidant levels. These compounds combined with cisplatin caused upregulation in the pro-apoptotic Bax, Bid, caspase-3, caspase-8, caspase-9, Fas, and p53 gene expressions while downregulating anti-apoptotic DFFA, NFkB1, and Bcl2 gene expressions. These combinations caused vascular loss and a reduction in VEGF expression. Conclusion: These results suggest that a combinational regimen of coumarin compounds with cisplatin could enhance the effect of cisplatin in A549 cells. Besides, these compounds exhibit relatively low toxicity in normal cells, thus decreasing the dose requirement of cisplatin in cancer treatments.
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    Novel triazole substituted phthalocyanines showing high singlet oxygen quantum yields
    (Elsevier, 2019) Demirbas, Umit; Bayrak, Riza; Dilber, Gulsev; Mentese, Emre; Akcay, Hakki Turker
    In this study, novel triazole peripherally substituted phthalocyanine zinc(II) complexes 3(a-d) were synthesized from four different phthalonitrile derivative and characterized by FT-IR NMR, MALDI-TOF, UV-Vis methods. Aggregation-concentration relations of the compounds 3(a-d) were investigated by UV-Vis spectroscopy. Fluorescence quenching properties of the phthalocyanines 3(a-d) were studied and fluorescence quantum yields were calculated by comparative method. Photodegradation quantum yields of the compound 3(a-d) were calculated. In addition, singlet oxygen quantum yields of the compounds 3(a-d) were measured by comparative method by using 1,3-diphenylisobenzofuran (DPBF) as singlet oxygen quencher. In this work, it has been observed that the synthesized novel phthalocyanines have higher quantum yield values (the range of 0.8-0.85) compared to the Zn (II) complex of unsubstituted phthalocyanine (0.67). Especially the compound 3d substituted tolyl group has the highest singlet oxygen quantum yield (0.85) seen rarely in literature.
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    Synthesis of some new Methoxy Bridged Benzimidazolyl-Substituted phthalocyanines as potent inhibitors of urease
    (Elsevier Science Sa, 2018) Demirbas, Umit; Mentese, Emre; Sokmen, Bahar Bilgin; Bayrak, Riza; Akcay, Hakki Turker
    In this study, the novel peripherally 4-[(2-methyl-1H-benzimidazol-1-yl)methoxy] substituted Zn(II) (3) Cu(II) (4), Co(II) (5) phthalocyanines were prepared and their structures were characterized spectro-scopically. The light absorption behaviors of the synthesized compounds (3-6) were studied by UV-Vis spectroscopy in the different concentration and different solvents were studied also. In addition, the urease inhibition activities of the synthesized compounds were also investigated. Among the synthesized molecules, compound 5 showed the best inhibitory effect against jack bean urease with IC50 values of 0.0034 +/- 0.0010 mu M. (C) 2018 Elsevier B.V. All rights reserved.