Browsing by Author "Karahan, Fatih"

Now showing 1 - 8 of 8

The Determination of Inhibition Effect of Extracts of Thymbra Sintenisii Bornm. Et Aznav. Subsp on Angiotensin Converting Enzyme
(2020) Türkoğlu, Vedat; Baş, Zehra; Gür, Tuğba; Karahan, Fatih
Angiotensin converting enzyme (ACE, peptidyldipeptidase A, EC 3.4.15.1) has got a significant role in the arrangement of blood pressure. ACE inhibitors usually play a part in the therapies of hypertension. Hypertension is an significant cardiovascular risk factor. The main purpose of the treatment is to reduce the incidence of hypertension. In this study, the inhibition effect of butanol and water extracts of Thymbra sintenisii Bornm. et Aznav. Subsp on angiotensin converting enzyme (ACE) activity in human plasma was investigated. ACE activity was calculated at 345 nm spectrophotometrically. Extracts of Thymbra sintenisii Bornm. et Aznav. subsp plant with water and butanol were made. The effectiveness of these extracts on ACE activity was researched. Water and butanol extracts of Thymbra sintenisii indicated inhibition impact on ACE. IC50 values for water and butanol extracts of Thymbra sintenisii was measured to be 1.696 mg mL-1 and 0.395 mg mL-1 respectively. Inhibition type for water and butanol extracts of Thymbra sintenisii from Lineweaver-Burk chart was defined to be non-competitive inhibition. Synthetic ACE inhibitors are utilized in the therapy of hypertension. On the other hand, synthetic ACE inhibitors exhibit a large number of adverse effects. Therefore, ACE inhibitors have been newly researched from native herbs. These conclusions demonstrate that water and butanol extracts of Thymbra sintenisii plant may have an ACE inhibition capacity.
Determination of Serum 8-Hidroksi2'-Deoksiguanosine (8-OHDG) Levels of Lycopene Treated Experimental Diabetic Rats
(2012) Karahan, Fatih; Dede, Semiha
Bu çalışma, deneysel olarak diyabet meydana getirilen ratlarda, pro-enflamatuar ve antioksidan olarak koruyuculuğu bilinen likopen uygulanmasının, DNA hasar göstergesi olan 8-OHdG düzeyleri üzerine etkilerini ortaya koymak ve likopenin diyabet komplikasyonlarındaki olası rolünü araştırmak amacıyla planlandı. Diyabet oluşturmak için D ve DL grup ratlara 45 mg/kg tek doz streptozotosin (STZ) intraperitoneal (i.p) yoldan uygulandı. Kontrol grubuna ise aynı miktarda serum fizyolojik enjekte edildi. Kan şekerleri 270 mg/dl ve üzerinde olanlar diyabetik olarak kabul edilip çalışmaya dahil edildi. L ve DL grubundaki ratlara Likopen ayçiçeği yağında çözdürülerek 10 mg/kg/gün olarak uygulandı. Dört haftalık denemeden sonra toplanan kan örneklerinde glukoz, %HbA1c, serum 8-hidroksi?2'-deoksiguanozin (8-OHdG) düzeyleri tespit edildi. Diyabet + likopen uygulanan grupta kan glukozu ve %HbA1c kontrol ve sadece likopen uygulanan gruplara göre artmış olmakla beraber (p<0.05), diyabet grubundan önemli oranda düşük (p<0.05) olduğu görüldü. 8-OHdG düzeyleri istatistiksel olarak değerlendirilmesi sonucunda, deneysel diyabet oluşturulan grupta DNA hasarının en yüksek (p<0.05) olduğu görüldü. Kontrol ve likopen gruplarında 8-OHdG bakımından istatistiksel olarak anlamlı bir fark saptanmadı. Diyabet+ likopen grubunda ise 8-OHdG düzeylerinin diyabet grubuna göre likopen uygulanmasını takiben anlamlı ölçüde azaldığı ve kontrol ve sadece likopen uygulanan gruplara göre anlamlı (p>0.05) bir şekilde fark olmadığı görüldü. Anahtar Sözcükler: 8-hidroksi?2'-deoksiguanozin, Diabetes Mellitus, HbA1c, Likopen, Rat, STZ
Electrochemical Determination of Fluoroquinolone Antibiotic Norfloxacin in the Presence of Anionic Surfactant Using the Anodically Pretreated Boron-Doped Diamond Electrode
(Wiley-v C H verlag Gmbh, 2020) Karahan, Fatih; Basi, Zehra; Keskin, Ertugrul; Pinar, Pinar Talay; Yardim, Yavuz; Senturk, Zuhre
In this article, a simple, fast and inexpensive methodology has been developed for the determination of fluoroquinolone class antibiotic norfloxacin (NFX) in anionic surfactant media (sodium dodecyl sulphate, SDS) using an anodically pretreated boron-doped diamond (APT-BDD) electrode. Cyclic voltammetric studies showed that the NFX gave an irreversible and adsorption controlled anodic oxidation signal at a potential of about +1.32 V on the APT-BDD electrode. The effects of parameters such as the electrode pre-treatment procedure, SDS concentration, and instrumental variables on the electrochemical sensitivity of NFX were evaluated. Under optimized conditions, the linearity was achieved in the range of 0.05 to 4.0 mu g mL(-1) (1.57x10(-7)-1.25x10(-5) mol L-1), with a detection limit of 0.013 mu g mL(-1) (4.07x10(-8) mol L-1) by using square-wave adsorptive stripping voltammetry (SW-AdSV). The feasibility of the developed approach for the quantification of NFX in urine samples was tested.
Enhanced Purification Protocol for the Angiotensin-Converting Enzyme From Bovine Systems and Investigation of the in Vitro Effect of Some Active Substances
(Elsevier Ireland Ltd, 2021) Karahan, Fatih; Turkoglu, Vedat
Angiotensin-converting enzyme (ACE, EC 3.4.15.1) synthesized by endothelial cells and responsible for the regulation of blood pressure was purified from the bovine lung with affinity chromatography method. The purification rate of the ACE of the bovine lung was calculated as 1748- fold. Optimum pH and optimum temperature for the purified ACE were found to be 7.6 and 35-40 degrees C, respectively. The purity and molecular weight of the ACE were designated with SDS-PAGE. The ACE was found to have three subunits with molecular weights of 57 kDa, 66 kDa, and 190 kDa. Then, the total molecular weight of the ACE was designated as 303 kDa with gel filtration chromatography. The effects of ACE inhibitors captopril, fosinopril, lisinopril, and beta-blockers propranolol, atenolol, and diuretic triamterene on ACE activity were studied. ACE inhibitors lisinopril, captopril, fosinopril, and diuretic triamterene demonstrated an inhibition effect on ACE activity. Beta-blockers indicated no effect on ACE. IC50 values of captopril, fosinopril, lisinopril, and triamterene from the graphical equation were calculated as 0.835 nM, 1.159 IrM, 4.085 nM, and 227 IrM, respectively. The inhibition type and Ki values of these compounds were determined from Lineweaver-Burk plots. Captopril, fosinopril, lisinopril, and triamterene demonstrated a non-competitive inhibition effect on ACE activity. Ki constants were found as 1.057 nM, 1.675 IrM, 6.449 nM, and 419.5 IrM, respectively. Captopril indicated the highest inhibitor effect with an IC50 value of 0.835 nM.
In Vitro Effect of Ethyl Acetate, Butanol and Water Extracts of Juniperus Excelsa Bieb. on Angiotensin-Converting Enzyme Purified From Human Plasma
(Springer international Publishing Ag, 2019) Basi, Zehra; Turkoglu, Nalan; Turkoglu, Vedat; Karahan, Fatih
Angiotensin-converting enzyme (ACE) was purified from human plasma by affinity chromatography. Effect of ethyl acetate, butanol and water extracts of Juniperus excelsa Bieb. (J. excelsa) fruits on purified ACE activity was investigated. ACE was purified 3659-fold with a specific activity of 1350 EU/mg protein from human plasma. The purity and molecular weight of ACE were determined by SDS-PAGE, and two bands 60kDa and 70kDa are seen on the gel. Ethyl acetate extract of J. excelsa fruits showed an activation effect on human plasma ACE activity. Butanol and water extracts of J. excelsa fruits showed an inhibition effect on ACE activity. IC50 values for butanol and water extracts of J. excelsa fruits were calculated to be 2.858mg/mL and 5.790mg/mL, respectively. Lisinopril was used to be reference inhibitor. Type of inhibition for all inhibitors was designated as non-competitive. IC50 value and K-i constant for lisinopril were determined to be 0.781nM and 0.662nM, respectively. These results show that butanol and water extracts of J. excelsa plant may have an ACE inhibitor potency.
Investigation of the in Vitro Effect of Some Active Substance That Prevent Hypertension on Angiotensin Converting Enzyme (ace Ec 3.4.15.1) Purified From Bovine Lung by Affinity Chromatography Method
(2019) Karahan, Fatih; Türkoğlu, Vedat
Endotel hücreleri tarafından sentez edilen ve kan basıncının düzenlenmesinden sorumlu olan anjiotensin konverting enzim (ACE EC 3.4.15.1), sığır akciğerinden afinite kromatografisi yöntemi ile saflaştırıldı ve sığır akciğeri anjiotensin konverting enziminin saflaştırma oranı 1748 kat olarak hesaplandı. Saflaştırılan ACE için optimum sıcaklık ve pH sırasıyla 35-40 oC ve 7.6 olarak bulundu. SDS-PAGE ile ACE'in 57 kDa, 66 kDa ve 190 kDa molekül ağırlığında üç alt birime sahip olduğu görüldü. Daha sonra jel filtrasyon kromatografisi yöntemi ile enzimin molekül ağırlığı belirlendi ve ACE'in molekül ağırlığı 303 kDa olarak hesaplandı. ACE inhibitörleri lisinopril, kaptopril, fosinopril, beta blokerer atenolol, propranolol, diüretikler triamteren, spironolakton ve indapamidin ACE aktivitesi üzerine etkileri araştırıldı. Ancak spironolakton ve indapamid saf su içinde çözünmediğinden dolayı çalışılamadı. ACE inhibitörleri lisinopril, kaptopril, fosinopril ve diüretik olan triamteren, ACE aktivitesi üzerinde inhibisyon etkisi gösterirken beta blokerleri herhangi bir etki göstermedi. Lisinopril, kaptopril, fosinopril ve triamterenin gibi etken maddeler ACE aktivitesi üzerine yarışmasız inhibisyon gösterdi ve grafikleri çizildi. Grafik denkleminden bu bileşiklerin IC50 değerleri hesaplandı. Sığır akciğeri ACE aktivitesi üzerine inhibisyon etkisi gösteren bu etken maddelerin IC50 değerleri, sırasıyla 4.085 nM, 0.835 nM, 1.159 µM ve 227 µM olarak hesaplandı. Aynı zamanda lisinopril, kaptopril, fosinopril ve triamteren için Ki sabitleri, sırasıyla 6.449 nM, 1.057 nM, 1.675 µM ve 419.5 µM olarak hesaplandı. Kaptopril, 0.835 nM IC50 değeri ile en yüksek inhibitör aktivitesini gösterdi.
A Novel Nonenzymatic Hydrogen Peroxide Amperometric Sensor Based on Pd@ceo2-Nh2 Nanocomposites Modified Glassy Carbon Electrode
(Elsevier Science Bv, 2018) Guler, Muhammet; Turkoglu, Vedat; Kivrak, Arif; Karahan, Fatih
Herein, (3-aminopropyl)triethoxysilane functionalized cerium (IV) oxide (CeO2-NH2) supported Pd nano particles were synthesized. The nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and High-resolution transmission electron microscopy (HRTEM). The Pd@CeO2-NH2 showed better electrocatalytic response to the reduction of H2O2 than CeO2-NH2. The fabricated sensor exhibited two linear responses to the reduction of H2O2. The first one was from 0.001 to 3.276 mM with 0.47 mu M of a limit of detection (LOD) (S/N = 3) and excellent sensitivity of 440.72 mu A mM(-1) cm(-2) and the second one was from 3.276 to 17.500 mM with the sensitivity of 852.65 mu A mM(-1) cm(-2) in the optimum conductions. Also, the sensor exhibited 91% of electrocatalytic activity toward H2O2 after having been used for 30 days and the reproducibility was also satisfactory. The sensor response to H2O2 was not affected by ascorbic acid, fructose, glycine, dopamine, arginine, mannose, glucose, uric acid, Mg+2, Ca+2, and phenylalanine at the studied potential. Also, the fabricated sensor was used to determine H2O2 in milk samples. The results show that the constructed sensor can be a promising devise for the determination of H2O2 in real samples.
Omega Asitleri (3, 6, 9) ve Stearik Asidin Sıçanlarda İskemi Reperfüzyon Hasarında Fizyolojik ve Histopatolojik Etkilerinin Araştırılması
(2024) Gür, Tuğba; Arıhan, Okan; Oto, Gökhan; Yildirim, Serkan; Kömüroğlu, Ahmet Ufuk; Karahan, Fatih
İskemi, organ veya dokuya yetersiz kan akışı nedeniyle geri dönüşümlü veya geri dönüşümsüz hücre veya doku hasarına neden olur. Bu çalışmada 10 gruba ayrılan 70 adet dişi Wistar-albino sıçanın bacak kaslarına (kuadriseps) iskemi-reperfüzyon hasarı öncesi uygulanan omega 3, 6, 9 ve stearik asit yağ asitlerinin etkinliği araştırıldı. Çalışma 14 gün boyunca aynı dozda devam etti. Ayrıca bu yağ asitleri iskemi-reperfüzyon yapılmadan diğer gruplara da verildi. Uygulama sonrasında sıçanlarda farklı yağ asitlerinin kan biyokimyasal parametreleri, oksidatif stres parametreleri ve histopatoloji incelendi. Sonuç olarak omega 9 yağ asidinin histopatolojik özellikler ve oksidatif stres indeksi açısından diğer omega yağ asitleri ve stearik asit ile karşılaştırıldığında daha iyi koruyucu özelliklere sahip olduğu gözlendi. Ayrıca diğer yağ asitleri ve stearik asit, iskemi-reperfüzyonun zararlı etkilerine karşı bir dereceye kadar koruma sağlamıştır.