Araştırmacılar(47)

• Adiguzel, Ekrem
• Alp, Cemalettin
• Altay, Ahmet
• Altın, Sevgi
• Anwer Alemdar, Mohammed B.
• Aydemir, Ismihan E.
• Aygün, Sıdkı
• Bayraktar, Taha
• Beşer, Burcu Meryem
• Burmaoglu, Serdar
• Bursal, Ercan
• Caglar, Sema
• Coldur, Fatih
• Çağlar, Bülent
• Çardak, Seda
• Çatır, Mustafa
• Çubuk, Osman
• Degirmenci, Sebnem
• Dikici, Emrah
• Dogancay, Nesrin
• Emul, Zeynep
• Gedik, Kubra
• Gülçin, İlhami
• Icer, Fatih
• Işik, Mesut
• Kalın, Şeyda Nur
• Koçak, Süleyman
• Koktepe, Tubanur
• Korkmaz, Kubilay
• Köksal, Ekrem
• Lacin, Gamze
• Meryem Aydn, Burcu
• Onder, Ahmet
• Ozdokur, Volkan Kemal
• Özdokur, Kemal Volkan
• Parvin, Maliha
• Sahin, Erdal
• Sarp, Gokhan
• Saykal, Tuba
• Solakyildirim, Kemal
• Suyurdu, Tuba Nur
• Tohma, Hatice
• Topcu, Cihan
• Tozoglu, Fatih
• Ubuk, Osman
• Ulutaş, Yakup
• Yildirim, Berat

• ArticleYalnız künye2026/r/ebyu/11069
  Fabrication of a PVC Membrane Sensor Based on a HKUST-1 Metal-organic Framework for Direct Determination of Cysteamine in Pharmaceutical Formulation

  Kaya, Lutfi; Coldur, Fatih; Kanberoglu, Gulsah Saydan

  Background: The most common use of cysteamine is the treatment of cystinosis. Excessive intake of cysteamine can lead to serious side effects and health complications. Therefore, the monitoring of cysteamine levels is highly significant. Objective: Several techniques have been developed to measure cysteamine accurately. Many of these methods are constrained by various limitations, including labor-intensive pre-treatment procedures, sophisticated equipment, skilled operators, and costly consumables. The present study aims to fabricate a cysteamine-selective potentiometric sensor based on HKUST-1 metal-organic framework exhibiting a wider linear range and more sensitive potentiometric responses compared to the ion pair-based cysteamine-selective sensor that was developed previously. Methods: A novel PVC membrane cysteamine-selective sensor was fabricated by coating the membrane cocktail consisting of poly(vinyl chloride), HKUST-1 metal-organic framework, plasticizer (o-nitrophenyloctylether), and ionic additive (potassium tetrakis (4-chlorophenyl) borate) onto the conductive solid contact surface. The potentiometric performance characteristics of the sensor were evaluated in detail. Results: The sensor exhibits a linear response to cysteamine concentration in the range of 1.0×10−6 M -1.0×10−2 M (R2=0.9958) with a slope of 51.5 mV/decade and a detection limit of 8.0×10-7 M. It operates effectively within a pH range of 3.9-5.7 and displays a rapid response time. Conclusion: Compared to the cysteamine-selective sensor available in the literature, the current sensor stands out with its wider linear operating range and lower detection limit. The sensor consistently yields reproducible and stable potentiometric responses towards cysteamine. The fabricated cysteamine-selective sensor effectively quantifies cysteamine content in pharmaceutical formulations. 2026, Bentham Science Publishers

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• ArticleYalnız künye2026/r/ebyu/11036
  Efficient fabrication of a benzydamine-selective PVC-membrane potentiometric sensor with broad dynamic range and ultra-low detection limit

  Kircaer, Ozan; Kanberoglu, Gulsah Saydan; Coldur, Fatih

  A potentiometric poly(vinyl chloride) (PVC) membrane benzydamine (BZD)-selective sensor based on potassium tetrakis(4-chlorophenyl)borate (KTpClPB) as an electroactive material was fabricated with a broad linear range and ultra-low detection limit in a straightforward, cost-effective, and efficient manner. As an outcome of the membrane optimization research, it was found that the membrane composition that exhibited the best potentiometric performance metrics among the studied membrane compositions was 32.0% (w/w) PVC, 67.0% (w/w) o-NPOE (o-nitrophenyloctyl ether), and 1.0% (w/w) KTpClPB. The sensor displayed a linear response to BZD within the concentration range of 1.0 × 10−8 to 1.0 × 10−2 mol L-1, achieving a detection limit of 5.0 × 10− 9 mol L-1 and a sensitivity of 56.6 mV decade−1. The electrodes possessed a rapid response time of about 10 s. The sensor’s analytical capability was demonstrated by accurately quantifying the benzydamine content in multiple pharmaceuticals with benzydamine as the active component, yielding high recovery values.

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• ArticleYayıncıda açık erişim2026/r/ebyu/10973
  A novel PVC-membrane potentiometric sensor based on molecularly imprinted polymer for the determination of rhodamine B

  Kanberoglu, Gulsah Saydan; Kaya, Nurcan; Coldur, Fatih; Hashemi-Moghaddam, Hamid; Soylak, Mustafa

  A rhodamine B (RH-B)-imprinted functional polymer was synthesized by free radical polymerization, utilizing RH-B as the template, methacrylic acid as the functional monomer, and ethyleneglycol dimethylacrylate as the cross-linker. The synthesized RH-B-imprinted polymer was characterized by FT-IR measurements. A novel RH-B-selective potentiometric poly(vinyl chloride) (PVC) membrane sensor was fabricated using this newly synthesized RH-B-imprinted functional polymer as the ionophore. Membrane optimization studies revealed that the most satisfactory membrane composition, yielding the best potentiometric parameters, comprised 32.0% (w/w) PVC, 64.0% (w/w) dibutyl phthalate, 3.0% (w/w) RH-B-imprinted polymer, and 1.0% (w/w) potassium tetrakis(4-chlorophenyl)borate. Further investigations into the potentiometric performance characteristics of the optimum composition demonstrated that the sensor exhibited a linear response to RH-B within the concentration range of 1.0 × 10–7 to 1.0 × 10–2 M with a detection limit of 1.0 × 10–8 M and a near Nernstian slope of 67.37 mV/decade. The sensor’s analytical proficiency was evidenced by its precise quantification of RH-B in RH-B-spiked rose-water samples, resulting in satisfactory recovery rates.

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• ArticleYalnız künye2026/r/ebyu/10912
  Machine learning (ML)-assisted first-principles DFT study of mechanical properties, electron–hole recombination, and enhanced light absorption in transition metal trioxides for photocatalytic applications

  Jameel, Muhammad Hasnain; Ullah, Muhammad Abaid; Khan, Maaz; Arain, Samia; Parvin, Maliha; Abdullah, Danish; Luo, Jia; Wang, Hongyan

  Developing efficient transition metal trioxides (TMOs) is difficult due to the critical impact of electron–hole recombination and optical absorption on photocatalytic activity. In this study, we develop a machine learning (ML)-assisted DFT framework to accelerate the screening of TMOs by predicting key properties such as bandgap energy, electron–hole recombination rates, and light-absorption efficiency. A comprehensive dataset of over 50 TMO materials is generated, and descriptors including unit cell volume, density, formation energy, and structural parameters are analyzed. ML models such as supervised regression models are trained to predict electronic and photocatalytic properties. Principal component analysis (PCA) reveals that bandgap energy, unit cell volume, and density are the most influential factors controlling electron–hole recombination, surface area, and light absorption. A machine learning-driven random forest regression model accurately predicts the energy bandgap of transition metal trioxides (WO3, VO3, and CrO3), achieving high performance with training R2 values of 0.937–0.959 and strong generalization with testing R2 values of 0.906–0.970. The random forest regression (RFR) model exhibits satisfactory performance during testing (R2 = 0.936), (R2 = 0.964), and (R2 = 0.894) enabling the rapid identification of top-performing TMO candidates. DFT calculated electronic band structures reveal a clear evolution from metallic to semiconducting behavior, with ReO3 exhibiting a zero-band gap (Eg), while VO3 (0.99 eV), CrO3 (1.41 eV), and WO3 (1.55 eV) display suitable band gaps (Eg) for photoinduced charge excitation. Optical response analysis shows strong light absorption on the order of 105–106 cm−1 indicating efficient photon harvesting across the ultraviolet and visible regions. WO3 combines a favorable band gap with high optical conductivity (~ 23.64 Ω−1 cm−1), strong absorption (8.0 × 105 cm−1), and comparatively low reflectivity (~ 0.35), making it particularly effective for visible-light-driven photocatalysis. This work demonstrates the effectiveness of combining ML with first-principles calculations to efficiently screen and design TMOs, providing a powerful strategy for the rational development of high-performance photocatalysts.

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• ArticleAçık Erişim2026/r/ebyu/10844
  Folliculi sennae Extract: A Multifunctional Approach to Alzheimer’s and Diabetes

  Guney, Turkan; Altin, Sevgi; Dikici, Emrah; Isik, Mesut; Koksal, Ekrem

  Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) exhibit overlapping molecular pathways characterized by oxidative imbalance and enzyme dysfunction. This study provides a comprehensive evaluation of the multifunctional potential of Folliculi sennae (F. sennae) ethanol extract as a natural therapeutic agent targeting these disorders. Phenolic profiling using LC–MS/MS revealed abundant bioactive compounds, including quercetin, luteolin, kaempferol, and gallic acid, with high linearity and reproducibility. The extract exhibited moderate antioxidant activity across DPPH, ABTS, FRAP, and CUPRAC assays, highlighting its redox-modulating capacity. Importantly, enzyme inhibition assays demonstrated notable inhibition of acetylcholinesterase (AChE, IC50 = 10.34 µg/mL), butyrylcholinesterase (BChE, IC50 = 7.72 µg/mL), and α-glucosidase (IC50 = 6.66 µg/mL), indicating potential neuroprotective and antidiabetic effects. These findings suggest that F. sennae orchestrates a synergistic interplay between antioxidant defense and targeted enzymatic inhibition, positioning it as a promising multitarget natural candidate for managing oxidative stress–linked neurodegenerative and metabolic disorders. The study lays the biochemical groundwork for future translational research exploring F. sennae as a safe, plant-based therapeutic intervention.

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• ArticleYayıncıda açık erişim2026/r/ebyu/10834
  Metabolite Profiling of Lavender (Lavandula pedunculata subsp. cariensis) Essential Oil and Investigation of Its Potential Antioxidant and Enzyme-Inhibitory Effects

  Karageçili, Hasan; Özden, Eda Mehtap; Mutlu, Muzaffer; Bingöl, Zeynebe; Akıncıoğlu, Hülya; Köksal, Ekrem; Gören, Ahmet Ceyhan; Gülçin, İlhami

  Background/Objectives: Lavandula cariensis species is cultivated uncommonly in the western region of Turkey. The colloquial appellations avayianos, karabasi, and myra are used to refer to the L. cariensis plant. The essential oil of L. cariensis was studied for its potential antiglaucoma, antioxidant, antidiabetic, and acetylcholinesterase inhibitory effects. Methods: The inhibitory effect of the essential oil of L. cariensis on the acetylcholinesterase (AChE), carbonic anhydrase II (CA II), and α-amylase enzymes was determined. Therefore, chemical profiles of L. cariensis’ essential oil were identified using Gas Chromatography Mass Spectrometry (GC-MS) and as Chromatography with Flame Ionization Detection (GC-FID) analyses. Results: Camphor (39.73%), fenchone (19.49%), exobornyl acetate (6.81%), camphene (5.49%), and eucalyptol (5.49%) were the most abundant compounds in L. cariensis essential oil. Radical scavenging effect of the essential oil of L. cariensis was examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50: 231.0 ± 0.094 μg/mL) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) (IC50: 7.45 ± 0.013 μg/mL) radicals. Also, the ferric ions (Fe3+), cupric ions (Cu2+), and Fe3+-2,4,6-tri(2-pyridyl)-S-triazine (TPTZ) complex reducing capabilities were studied. Additionally, essential oil of L. cariensis indicated a comparable level of inhibition towards hCA II (IC50: 276.42 μg/mL), AChE (IC50: 14.22 μg/mL), and α-amylase (IC50: 475.63 μg/mL) enzymes. Conclusions: The evaluation of the antioxidant capabilities and enzyme inhibition profiling of the essential oil of L. cariensis will be made possible by this comprehensive study, which serves as a springboard for further research. The essential oil of L. cariensis demonstrated enzyme-inhibitory activities against target enzymes associated with Alzheimer’s disease, diabetes, and glaucoma. Also, this study’s in vitro inhibition suggests promising prospects.

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• ArticleYayıncıda açık erişim2026/r/ebyu/10702
  Antioxidant, Antidiabetic, Antiproliferative Activities, and Verbascoside Content of Four Endemic Verbascum Species: V. leiocarpum, V. ozturkii, V. alyssifolium, and V. tuna-ekimii

  Şimşek, Samed; Akşit, Hüseyin; Köksal, Ekrem; Altay, Ahmet

  This study, for the first time, investigated the antioxidant, antidiabetic, and antiproliferative properties of methanolic extracts from the aerial and root parts of four endemic Verbascum species—Verbascum leiocarpum Murb., Verbascum ozturkii Karavel., Uzunh. & S.Çelik, Verbascum alyssifolium Boiss., and Verbascum tuna-ekimii Karavel., A.Duran & Hamzaoğlu—and quantitatively determined their verbascoside content using HPLC-DAD. Antioxidant capacity was evaluated by DPPH and FRAP assays, and total phenolic content (TPC) and total flavonoid content (TFC) were also determined. Antidiabetic activity was assessed through α-glucosidase inhibition, and antiproliferative effects were determined in A549, MDA-MB-453, and HT-29 human cancer cell lines. Among the tested samples, the root of V. leiocarpum exhibited the highest TPC (50.89 mg GAE/g extract), FRAP value (124.16 mg TE/g extract), DPPH scavenging ability (IC50: 58.82 μg/mL), and verbascoside content (129.06 mg verbascoside/g extract). This extract also exhibited significant antiproliferative effects against A549 and MDA-MB-453 cells, with inhibition rates of 85% and 69%, respectively. In contrast, both aerial and root extracts of V. tuna-ekimii exhibited low biological activity and a lower concentration of verbascoside. Pearson correlation analysis demonstrated strong positive associations between verbascoside content and both antioxidant and antiproliferative parameters. However, no significant correlation was found between verbascoside content and α-glucosidase inhibition, suggesting that other phytochemicals may be responsible for the antidiabetic activity. These findings indicate that V. leiocarpum, especially its root extract, may be considered a valuable source of natural antioxidants and antiproliferative agents. The study highlights the pharmacological potential of endemic Verbascum species that have not been comprehensively investigated phytochemically or pharmacologically and supports their further evaluation in the context of phytopharmaceutical research.

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• ArticleYalnız künye2026/r/ebyu/10607
  ZnBi2O4/Ag2WO4 nanocomposite for efficient photocatalytic removal of dye and pharmaceutical pollutants

  Yavuz, Sevtap Caglar; Emul, Zeynep; Icer, Fatih; Yavuz, Emre; Ozdokur, Volkan Kemal; Cirak, Burcu Bozkurt

  This paper targets to synthesize a nano-composite with high photocatalytic performance and research the possibility of utilizing it for dye and drug removal from wastewater. Herein, ZnBi2O4/Ag2WO4 nanocomposite photocatalyst was successfully synthesized via two step hydrothermal/precipitation method. The photocatalytic activity of the synthesized nanocomposite was evaluated by its effect on the degradation of methylene blue dye and sulfamerazine drug under UV light. The results revealed that the ZnBi2O4/Ag2WO4 nanocomposite achieved a significantly higher photocatalytic efficiency (96% degradation of methylene blue in 1 h) compared to ZnBi2O4 (41%) and Ag2WO4 (76%) within only 60 min. The exceptional photocatalytic degradation efficiency of the ZnBi2O4/Ag2WO4 nanocomposite against methylene blue and sulfamerazine can be attributed to the effects of reduced charge carrier recombination resulting from the synergistic effect of surface adsorption-photocatalytic degradation interaction of ZnBi2O4 and Ag2WO4.

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• ArticleYalnız künye2026/r/ebyu/10602
  Antioxidant and enzyme inhibitory potential of Tilia platyphyllos: An LC-MS/MS-guided phytochemical insight

  Dikici, Emrah; Altin, Sevgi; Isik, Mesut; Aggul, Ahmet Gokhan; Koksal, Ekrem; Rudrapal, Mithun

  This study focused on assessing the phenolic composition and biological activities of the ethanol extract of Tilia platyphyllos, including its anticholinesterase, antidiabetic, and antioxidant potential. LC-MS/MS analysis identified 14 phenolic compounds, with catechin as the major component. The total phenolic/flavonoid contents were determined as 48.07 µg GAE/mg and 88.46 µg QE/mg, respectively. The extract exhibited significant antioxidant capacity in DPPH, ABTS, FRAP, and CUPRAC assays, with radical scavenging activities of 20.61 ± 1.52% for DPPH and 28.13 ± 1.61% for ABTS at 0.2 μg/mL. It also inhibited linoleic acid peroxidation by approximately 51%, exhibiting greater efficacy than the standart antioxidants Trolox and α-tocopherol. In terms of cholinesterase inhibition, the extract showed potent activity against AChE and BChE, with IC₅₀ values of 1.08 ± 0.02 µg/mL and 1.18 ± 0.08 µg/mL, respectively—markedly more effective than tacrine, which had IC50 values of 3.19 ± 0.11 µg/mL for AChE and 2.51 ± 0.03 µg/mL for BChE. For antidiabetic evaluation, α-glucosidase inhibition was observed with an IC50 of 0.44 ± 0.01 µg/mL, outperforming acarbose (3.24 ± 0.09 µg/mL). These findings suggest that the phenolic-rich extract of Tilia platyphyllos may possess notable antioxidant, neuroprotective, and antidiabetic activities, highlighting its potential as a functional food or natural therapeutic agent.

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• ArticleYalnız künye2026/r/ebyu/10588
  Comprehensive Organ-Specific Phenolic Characterization of Endemic Hedysarum candidissimum by Liquid Chromatography–Tandem Mass Spectrometry: Antioxidant, Enzyme-Inhibitory, and Antiproliferative Activities Supported by Chemometric Analysis

  Şimşek, Samed; Varol, Tuğçe; Altın, Sevgi; Yılmaz, Mustafa Abdullah; Aydın, Ali; Elveren, Müjgan; Alp, Cemalettin; Köksal, Ekrem; Osma, Etem

  Hedysarum candidissimum (HC), a species endemic to Türkiye, represents a potential source of bioactive phytochemicals with pharmacological applications. This study provides the first comprehensive investigation of the species, integrating organ-specific phytochemical profiling with biological activity evaluations. Methanolic extracts from leaf, stem, and root were analyzed for their phytochemical composition and biological activities. Liquid Chromatography–Tandem Mass Spectrometry analysis quantified 53 phenolic compounds and revealed organ-dependent differences in metabolite distribution. Quinic acid was the major phenolic acid, with the highest content in the stem (91.81 mg/g extract), while flavonoid glycosides such as isoquercitrin (90.72 mg/g extract) and astragalin (43.61 mg/g extract) were higher in leaves. Antioxidant activity was determined by DPPH, FRAP, TPC, and TFC assays. The leaf extract showed the strongest activity, with the lowest DPPH IC50 (5.43 ± 0.18 µg/mL), highest reducing power (192.47 ± 0.91 mg TE/g extract), and highest phenolic and flavonoid contents (220.84 ± 1.07 mg GAE/g extract and 107.26 ± 0.77 mg QE/g extract). Enzyme inhibition assays demonstrated strong activity against acetylcholinesterase, butyrylcholinesterase, and α-glucosidase (2.44 ± 0.11, 3.35 ± 0.37, and 3.40 ± 0.20 µg/mL). Antiproliferative activity showed moderate growth inhibition in lung (A549, Calu1, H1650) and breast (MCF-7, MDA-MB-231) cancer cell lines (GI50: 2.40–19.15 µg/mL), with higher sensitivity in breast cells. The stem extract exhibited the highest tumor selectivity index (1.83), while LDH assays indicated low toxicity. Multivariate analyses confirmed organ-specific metabolite patterns and relationships between phenolic composition and biological activities. These findings indicate that the species, particularly the leaf extract, represents a source of phenolic metabolites for further phytochemical and biological investigation.

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