Person: OGAN, AYŞE
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
OGAN
First Name
AYŞE
Name
12 results
Search Results
Now showing 1 - 10 of 12
Publication Metadata only Investigation of HMG-CoA reductase inhibitory and antioxidant effects of various hydroxycoumarin derivatives(WILEY-V C H VERLAG GMBH, 2020) OGAN, AYŞE; Ozalp, Lalehan; Danis, Ozkan; Yuce-Dursun, Basak; Demir, Serap; Gunduz, Cihan; Ogan, AyseCardiovascular diseases are one of the primary causes of deaths worldwide, and the development of atherosclerosis is closely related to hypercholesterolemia. As the reduction of the low-density lipoprotein cholesterol level is critical for treating these diseases, the inhibition of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase, which is essentially responsible for cholesterol biosynthesis, stands out as a key solution to lower plasma cholesterol levels. In this study, we synthesized several dihydroxycoumarins and investigated their antioxidant and in vitro HMG-CoA reductase inhibitory effects. Furthermore, we carried out in silico studies and examined the quantum-chemical properties of the coumarin derivatives. We also performed molecular docking experiments and analyzed the binding strength of each coumarin derivative. Our results revealed that compoundIVdisplayed the highest HMG-CoA reductase inhibitory activity (IC50 = 42.0 mu M) in vitro. Cupric-reducing antioxidant capacity and ferric-reducing antioxidant power assays demonstrated that coumarin derivatives exhibit potent antioxidant activities. Additionally, a close relationship was found between the lowest unoccupied molecular orbital energy levels and the antioxidant activities.Publication Metadata only Kumarin türevlerinin fizyolojik pH’da sığır serum albümine bağlanmasının spektral ve moleküler yerleştirme ile incelenmesi(2022-10-05) MELETLİ, FURKAN; DANIŞ, ÖZKAN; OGAN, AYŞE; Meletli F., Kazancıçok Z., Akın N., Danış Ö., Ogan A.Serum albümin, kan plazmasında en yaygın bulunan proteinlerden biridir. Ozmotik basıncın ayarlanması,kan pH’nın belirlenmesi ve serbest radikallerin azaltılması gibi birçok farklı fizyolojik görevlerinin yanı sırakanda bulunan endojen ve eksojen maddelerin (yağ asitleri, ilaçlar ve metabolitler vb.) taşınmasında birincilişlevi olan çok fonksiyonlu ve önemli bir proteindir. İlaçlar hedeflerine ulaşmak için kan plazmasındataşınırken kaçınılmaz olarak serum albümin ile etkileşime girmektedirler. Serum albümin ile ilaç etkileşimiilacın terapötik etkisi hakkında bilgi vermektedir. Bu etkileşimlerin incelenmesi ilaç kimyasında, tıpta,biyoteknolojide ve biyokimyada önemli bir araştırma alanıdır. Sığır serum albümin (BSA), 582 amino asitkalıntısından oluşan ve insan serum albümini ile %76 benzerliği olan bir proteindir. Düşük maliyetli olması,yaygın olarak bulunabilmesi ve saflaştırma işleminin kolay olması nedeniyle BSA, araştırmacılar tarafındanligandların proteine bağlanma çalışmaları için sıklıkla tercih edilen, protein-ilaç etkileşimleri ve bağlanmamekanizmalarının belirlenmesi için model olan bir taşıma sistemidir. Kumarinler bir benzen halkası ilebir α-piron halkasının kaynaşması sonucu oluşan benzopiron adı verilen bir bileşik sınıfının üyesidirler.Doğal olarak bitkilerde bulunabildiği gibi sentetik olarak da elde edilebilmektedir. Kumarinlerin sahipoldukları konjuge çift halka sistemleri, onları farklı araştırma alanları için ilginç moleküller haline getirmiştir.Kumarin türevleri geniş bir biyolojik aktivite yelpazesi sergilemektedirler. Bunlar arasında anti-oksidan,anti-enflamatuar, anti-bakteriyel, anti-viral, anti-tümör ve anti-koagülan özellikleri öne çıkmaktadır.Kumarinler tıpta ve özellikle ilaç endüstrisinde yaygın olarak kullanılmaktadırlar. Çalışmamızda uygunEmilim, Dağılım, Metabolizma ve Atılım (ADME) özelliklerine göre farmakokinetik ve farmakodinamiketkileri iyi olan daha önceden sentezlenmiş ve karakterize edilmiş kumarin türevlerinin BSA’ya bağlanmalarıve taşınmaları in silico ve in vitro yöntemlerle araştırılmıştır. In silico çalışmalarda moleküler yerleştirme(moleküler docking) ve in vitro çalışmalarda UV-vis absorbans, floresans gibi multi-spektroskopik yöntemlerkullanılmıştır. BSA ile kumarin türevlerinin etkileşimleri in silico ve in vitro yöntemlerle aydınlatılmıştır. Insilico çalışmalar sonucunda kumarinlerin bağlanma enerjileri, ligand verimliliği değerleriyle birlikte proteinligandetkileşimleri ve konformasyonları belirlenmiştir. Ayrıca in vitro multi-spektroskopik analizlerindeğerlendirilmesiyle; bileşikler BSA’nın floresans şiddetinde, absorbansında ve ikincil yapısında değişikliklerizlenmiş, kuençleşme mekanizmaları, bağlanma sabitleri ve bağlanma bölgelerinin sayıları belirlenmiştir.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 Immobilization of acetylcholinesterase onto pyrrole-containing photocured thermosets(2023-04-01) DEMİR, SERAP; ÇAKMAKÇI, EMRAH; OGAN, AYŞE; ALI K. K., DEMİR S., ÇAKMAKÇI E., OGAN A.Acetylcholinesterase (AChE; EC 3.1.1.7) is a group of enzymes that catalyzes the hydrolysis of the neurotransmitter acetylcholine (ACh) into choline and acetate. AChE inhibition is commonly utilized as a biomarker for pesticides. In membrane based AChE biosensors the enzyme immobilization onto an electrode surface is of prime importance. In previous studies, conducting polymers-based supports have been used for the immobilization of AChE. In this study, a novel immobilization platform was developed. The simultaneous polymerization of pyrrole and functional thiol/ene monomers was performed to prepare conductive thermosets. AchE was covalently immobilized onto the membranes through the epoxy functional groups. After the immobilization process, the optimal temperature increased to 50 °C, displaying a better thermal stability and the optimum pH was elevated to 8.5. The activity of the immobilized enzyme was tested in the presence of several metals, and it was found that Cu2+ ions caused a noticable inhibition. After 10 cycles, the immobilized enzyme retained 51% of its original activity. In accordance with our results; the durability and the stability of the immobilized enzyme were improved. In future studies, the method applied here can be used in the design of an AchE biosensor.Publication Open Access In silico discovery of potential azole-containing mPGES-1 inhibitors by virtual screening, pharmacophore modeling and molecular dynamics simulations(2022-08-01) KÜÇÜKGÜZEL, İLKAY; OGAN, AYŞE; Ozalp L., KÜÇÜKGÜZEL İ., OGAN A.Inhibition of microsomal prostaglandin E-2 synthase-1 (mPGES-1) is promising for designing novel nonsteroidal anti-inflammatory drugs, as they lack side-effects associated with inhibition of cyclooxygenase enzymes. Azole compounds are nitrogen-containing heterocycles and have a wide use in medicine and are considered as promising compounds in medicinal chemistry. Various computer-aided drug design strategies are incorporated in this study. Structure-based virtual screening was performed employing various docking programs. Receiver operator characteristic (ROC) curves were used to evaluate the selectivity of each program. Furthermore, scoring power of Autodock4 and Autodock Vina was assessed by Pearson\"s correlation coefficients. Pharmacophore models were generated and Guner-Henry score of the best model was calculated as 0.89. Binding modes of the final 10 azole compounds were analyzed and further investigation of the best binding (- 8.38 kcal/mol) compound was performed using molecular dynamics simulation, revealing that furazan1224 (ZINC001142847306) occupied the binding site of the substrate, prostaglandin H-2 (PGH(2)) and remained stable for 100 ns. Continuous hydrogen bonds and hydrophobic interactions with amino acids in the active site supported the stability of furazan1224 throughout the trajectory. Pharmacokinetic profile showed that furazan1224 lacks the risks of inhibiting cytochrome P450 3A4 enzyme and central nervous system-related side-effects.Publication Metadata only Optimizing the immobilization conditions of beta-galactosidase on UV-cured epoxy-based polymeric film using response surface methodology(WILEY, 2021) OGAN, AYŞE; KAHRAMAN, MEMET VEZİR; DANIŞ, ÖZKAN; DEMİR, SERAP; Beyler-Cigil, Asli; Danis, Ozkan; Sarsar, Onur; Kahraman, Memet Vezir; Ogan, Ayse; Demir, SerapUV-cured epoxy-based polymeric film was prepared from glycidyl methacrylate, trimethylolpropane triacrylate, and poly(ethylene glycol) methylether acrylate. 2-hydroxy-2- methylpropiophenone was used as photo initiator. Covalent binding through epoxy groups was employed to immobilize beta-galactosidase from Escherichia coli onto this film, and immobilization conditions were optimized by the response surface methodology. ATR-Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis was carried out to characterize the epoxy-based polymeric film. Immobilization yield of beta-galactosidase on the material was calculated as 3.57 mg/g and the highest enzyme activity for the immobilized enzyme recorded at pH 6.5 degrees C and 60 degrees C. The immobilized enzyme preserved 51% of its activity at the end of 12 runs. Free and immobilized enzyme hydrolyzed 163.8 and 172.3 mu M lactose from 1% lactose, respectively. Kinetic parameters of both free and immobilized beta-galactosidase were also investigated, and K-m values were determined to be 0.647 and 0.7263 mM, respectively. Practical applications In our study we prepared a UV-cured epoxy-based polymeric film and optimized the immobilization conditions of beta-galactosidase from Escherichia coli onto this polymeric film by using response surface methodology (RSM). For this purpose, three-level and three-factor Box-Behnken design, which is an independent, rotatable or nearly rotatable, quadratic design, was applied. Optimal levels of three variables, namely, the amount of enzyme, immobilization time, and pH were determined using Box-Behnken experimental design. Lactose hydrolysis studies were performed from milk and lactose samples using free and immobilized enzyme. In addition, kinetic parameters, storage stability, and re-usability of immobilized beta-galactosidase were examined.Publication Metadata only Investigation of bioactive phytochemicals and in vitro antimicrobial effects ofMatricaria chamomilla L. and Tripleurospermum decipiens Bornm. on some urinarysystem pathogens(2022-05-25) OGAN, AYŞE; ZORLU N., Hatipoğlu S. D. Ç. , Bingöl D., DİNÇ H. Ö. , YÜKSEL MAYDA P., OGAN A.Publication Metadata only Antioxidant and anti-collagenase activity of st. John's wort (hypericum perforatum l.)(2022-11-30) ERDEM, SAFİYE; DANIŞ, ÖZKAN; OGAN, AYŞE; YILDIZ İ., Özalp L., ERDEM S., MOUTSİNGA E. G. B. K. , DANIŞ Ö., OGAN A.Publication Metadata only Preparation and antimicrobial properties of LL-37 peptide immobilized lignin/caprolactone polymer film(WILEY, 2020) OGAN, AYŞE; Ogan, Ayse; Yuce-Dursun, Basak; Abdullah, Deka; Beyler-Cigil, Asli; Kahraman, Memet Vezir; Caglayan, Pinar; Birbir, Meral; Mutlu, Ozal; Gulsoy, NagihanThe use of biopolymers has gained priority in tissue engineering and biotechnology, both as dressing material and for enhancing treatment efficiency. There is a demand for new biopolymers designed with protease inhibitors and antimicrobials. LL-37 is an important antimicrobial peptide in human skin and exhibits a broad spectrum of antimicrobial activity against bacteria, fungi, and viral pathogens. Using lignin which is an abundant carbohydrate polymer in nature and a polyacrylic acid, we prepared a lignin/caprolactone biodegradable film by plastifying caprolactone and polyacyrlic acid. Lignin/caprolactone biodegradable film was activated with CDI and then immobilized LL-37 peptide. The structure was elucidated in terms of its functional groups by attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and the morphology of the lignin/caprolactone biodegradable film was characterized by scanning electron microscopy (SEM) before and after the immobilization process. The amount of LL-37 immobilized was determined by ELISA method. It was found that 97% of LL-37 peptide was successfully immobilized onto the lignin/caprolactone biodegradable film. Antimicrobial activity was determined in the lignin/caprolactone biodegradable film samples by quantitative antimicrobial activity method. According to the results, LL-37 immobilized lignin/caprolactone biodegradable film samples were effective on test organisms; Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. In bio-compatibility assays, the ability to support tissue cell integration was detected by using 3 T3 mouse fibroblasts. Samples were examined under transverse microscope, non-immobilized sample showed a huge cellular death, whereas LL-37 immobilized lignin/caprolactone biodegradable film had identical cellular growth with the control group. This dual functional lignin/caprolactone biodegradable film with enhanced antibacterial properties and increased tissue cell compatibility may be used to design new materials for various types of biological applications.Publication Metadata only Investigation of bioactive phytochemicals of matricaria chamomilla L. and matricaria decipiens K. Koch and their in Vitro biological activities(2021-06-25) OGAN, AYŞE; Zorlu N., Hatipoğlu Çakmar D., OGAN A.