Browsing by Author "Turkoglu, Vedat"

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Determination of Malation, Methidathion, and Chlorpyrifos Ethyl Pesticides Using Acetylcholinesterase Biosensor Based on Nafion/Ag@rgo-nh2 Nanocomposites
(Pergamon-elsevier Science Ltd, 2017) Guler, Muhammet; Turkoglu, Vedat; Basi, Zehra
Herein, a facile electrochemical acetylcholinesterase (EC 3.1.1.7; AChE) biosensor based on nafion (NA) and Ag nanoparticles supported on amine functionalized reduced graphene oxide (rGO-NH2) was developed. The Ag@rGO-NH2 nanocomposite was characterized using Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). After being optimized, the biosensor exhibited excellent electrochemical response to the oxidation of thiocholine, the hydrolysis product of acetylthiocholine chloride (ATCl) catalyzed by AChE. An apparent Michealis-Menten value of 20.5 mu M was obtained. Under optimized conductions, the biosensor detected malation, methidathion, and chlorpyrifos ethyl in the linear range from 0.0063 to 0.077 mu g/mL, from 0.012 to 0.105 mu g/mL, and from 0.021 to 0.122 mu g/mL, respectively. The detection limit (LoD) was 4.5 ng/mL for malation, 9.5 ng/mL for methidathion, and 14 ng/mL for chlorpyrifos ethyl. Also, the NA/Ag@rGO-NH2/ AChE/GCE biosensor showed god sensitivity, stability and repeatability, which provides a promising tool for the detection of organophosphate pesticides. (C) 2017 Elsevier Ltd. All rights reserved.
The Effect of Some Antibiotics on Glutathione Reductase Enzyme Purified From Liver and Erythrocyte of Lake Van Pearl Mullet
(Taylor & Francis Ltd, 2015) Altun, Muhammed; Turkoglu, Vedat; Celik, Ismail
Context: The effect of antibiotics (amikacin, cefazolin, ivermectin, and kanamycin) on glutathione reductase (GR) isoenzymes activity in liver and erythrocyte of the fish, Chalcalburnus tarichi (Lake Van pearl mullet, Pallas 1811) (Cyprinidae) were investigated. Objective: This study determined the biochemical characterization of GR purified from the liver and erythrocytes of C. tarichi and the inhibition effect of the antibiotics on the GR isoenzymes. Materials and methods: GR was purified by affinity chromatography from the tissues of C. tarichi. The biochemical characterization of GR such as optimum temperature, optimum pH, and ionic strength were determined. The inhibition effects of the antibiotics on the isoenzymes were evaluated as IC50 and K-i values. K-i constant and 50% inhibitory concentration (IC50) value for antibiotics were determined by Lineweaver-Burk graphs and plotting activity % versus [ I], respectively, at five different concentrations of antibiotics. Results: Optimum temperature, pH, and ionic strength were determined for isoenzymes as 40 degrees C, 60 degrees C; 8.0, 8.0, and 50, 50 mM, respectively. Subunit molecular weights of the isoenzymes were estimated as 55 kDa by sodium dodecyl sulfate polyacrilamide gel electrophoresis (SDS-PAGE). In addition, IC50 and K-i values were calculated for amikacin, cefazolin, ivermectin, and kanamycin. The antibiotics showed non-competitive inhibition effects. IC50 values were calculated as 16.3, 36.6, 0.504, and 18.8mM for liver and 20.0, 30.4, 0.787, and 31.8 mM for erythrocyte, respectively. K-i constants were 13.9, 18.4, 0.654, and 11.2 mM for liver and 23.2, 46.4, 1.19, and 36.4 mM for erythrocyte, respectively. Discussion and conclusion: The results indicated that the antibiotics displayed non-competitive inhibition.
Effects of Some Drugs on Hepatic Glucose 6-Phosphate Dehydrogenase Activity in Lake Van Fish (Chalcalburnus Tarischii Pallas, 1811)
(Elsevier Science Bv, 2007) Ciftci, Mehmet; Turkoglu, Vedat; Coban, T. Abdulkadir
Inhibitory effects of some drugs on hepatic glucose 6-phosphate dehydrogenase from Lake Van fish (chalcalburnus tarischii pallas, 1811) were investigated. For this purpose, initially liver glucose 6-phosphate dehydrogenase was purified 899-fold in a yield of 46.24% by using 2',5'-ADP Sepharose 4B affinity gel. In order to control the purification of enzyme was done SDS polyacrylamide gel electrophoresis. SDS polyacrylamide gel electrophoresis showed a single band for enzyme. A constant temperature (+4'C) was maintained during the purification process. Enzyme activity was determined with the Beutler method by using a spectrophotometer at 340 nm. Vankomycine, sulfanylamide, sulfanylacetamide, nidazole, ciprofloxacin, amoxicillin and KMn04 were used as drugs. These drugs exhibited inhibitory effects on the enzyme. IC50 values of vankomycine, sulfanylamide, sulfanylacetamide, nidazole, ciprofloxacin, amoxicillin and KMn04 were 1.88, 0.037, 0.032, 1.178, 2.26, 643.5 and 0.0002 mM, and the Ki constants 1. 18 +/- 0.148, 0.119 +/- 0.021, 0.075 +/- 0.015, 1.15 +/- 0.21, 7.69 +/- 0.67, 1007 +/- 69, and 0.001 +/- 0.00022 mM, respectively. While vankomycine and nidazole showed competitive inhibition, others displayed noncompetitive inhibition. K-i constants and IC50 values for drugs were determined by Lineweaver-Burk graphs and plotting activity percentage versus [I], respectively. (C) 2006 Elsevier B.V. All rights reserved.
Electrochemical Detection of Malathion Pesticide Using Acetylcholinesterase Biosensor Based on Glassy Carbon Electrode Modified With Conducting Polymer Film
(Springer Heidelberg, 2016) Guler, Muhammet; Turkoglu, Vedat; Kivrak, Arif
Acetylcholinesterase (AChE) biosensor based on conducting poly([2,2;5';2 '']-terthiophene-3-carbaldehyde) (PTT) modified glassy carbon electrode (GCE) was constructed. AChE was immobilized on PTT film surface through the covalent bond between aldehyde and amino groups. The properties of PTT modified GCE were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The biosensor showed an oxidation peak at +0.83 V related to the oxidation of thiocholine, hydrolysis product of acetylthiocholine iodide (ATCI), catalyzed by AChE. The optimum current response of the biosensor was observed at pH 7.5-8.0, 40 degrees C and 120 U/cm(2) of AChE concentration. The biosensor showed a high sensitivity (183.19 mu A/mM), a linear range from 0.015 to 1.644 mM, and a good reproducibility with 1.7 % of relative standard deviation (RSD). The biosensor showed a good stability. The interference of glycin, ascorbic acid, histidine, uric acid, dopamine, and arginine on the biosensor response was studied. An important analytical response from these inteferents that overlaps the biosensor response was not observed. The inhibition rate of malathion as a model pesticide was proportional to its concentrations from 9.99 to 99.01 nM. The detection limit was 4.08 nM.
Electrochemical Sensing of Hydrogen Peroxide Using Pd@ag Bimetallic Nanoparticles Decorated Functionalized Reduced Graphene Oxide
(Pergamon-elsevier Science Ltd, 2018) Guler, Muhammet; Turkoglu, Vedat; Bulut, Ahmet; Zahmakiran, Mehmet
In this study, an excellent sensitive, selective, and stable electrochemical sensor was fabricated for the determination of hydrogen peroxide (H2O2) using nafion (Nf) and Pd@Ag bimetallic nanoparticles supported on (3-aminopropyl) triethoxysilane (APTES) functionalized reduced graphene oxide (rGO-NH2) modified glassy carbon (GC) electrode. The synthesized nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffractometer (XRD), and High-resolution transmission electron microscopy (HRTEM). The electrochemical properties of the nanocomposites were investigated by means of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Under optimized conditions, the electrochemical detection of H2O2 was carried out using amperometric method as well as CV. The linear range for H2O2 determination was 0.002-19.500 mM with a detection limit of 0.7 mu A and sensitivity of 1307.46 mu A mM(-1) cm(-2) due to the strong synergistic effect between Pd and Ag nanoparticles. The fabricated sensor was used for the determination of H2O2 in milk samples. The obtained results showed that the novel Nf/Pd@Ag/rGO-NH2/GC sensor can be used for the determination of H2O2 in real samples. (C) 2018 Elsevier Ltd. All rights reserved.
Electrochemical Sensing of Hydrogen Peroxide Using Pd@ag Bimetallic Nanoparticles Decorated Functionalized Reduced Graphene Oxide (Vol 263, Pg 118, 2018)
(Pergamon-elsevier Science Ltd, 2018) Guler, Muhammet; Turkoglu, Vedat; Bulut, Ahmet; Zahmakiran, Mehmet
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.
Exploration of Inhibitor Effect of Gly-Pro (Gp), Arg-Gly (Rgds) and Ser-Asp (Sdgrg) Bioactive Peptides on Angiotensin-Converting Enzyme Activity Purified From Human Serum
(Taylor & Francis inc, 2024) Adanas, Resul; Turkoglu, Vedat
Bioactive peptides (BPs) are a natural and important alternative to synthetic angiotensin-converting enzyme (ACE) inhibitors used in the treatment of hypertension. In this study, ACE was 3575-fold purified from human serum with the affinity chromatography process in one step. The molecular weight and purity of ACE were identified using the SDS-PAGE process and seen in two bands at around 60 kDa and 70 kDa on the gel. Vmax and KM values from the Lineweaver-Burk graphic were determined as 96.15 (mu mol/min) mL-1 and 0.2 mM, respectively. The effects of Gly-Pro (GP), Arg-Gly-Asp-Ser (RGDS) and Ser-Asp-Gly-Arg-Gly (SDGRG) BPs on purified ACE were researched. Also, lisinopril was used as a reference inhibitor. GP, RGDS and SDGRG on purified ACE demonstrated an inhibitory effect. IC50 values for these peptides were found as 184.71, 107.16 and 32.54 mu M, respectively. Ki values and type of inhibitory for GP, RGDS and SDGRG by the Lineweaver-Burk chart were found. The type of inhibitory for these peptides was calculated as reversible-competitive inhibitory. Ki values for GP, RGDS and SDGRG were calculated to be 260.02, 63.44 and 11.42 mu M, respectively. Also, the SDGRG indicated a higher inhibition effect on ACE activity than the GP and RGDS. The IC50 value of lisinopril was designated as 0.35 nM. The inhibition type of lisinopril was designated as reversible noncompetitive inhibition from the Lineweaver-Burk chart and the Ki value was 0.15 nM. Herein, it was concluded that GP, RGDS and SDGRG have ACE inhibitor potential.Communicated by Ramaswamy H. Sarma
Hematotoxic and Hepatotoxic Effects of Dichlorvos at Sublethal Dosages in Rats
(Wiley, 2009) Celik, Ismail; Yilmaz, Zeycan; Turkoglu, Vedat
The present study was designed to understand the effects of sublethal concentrations of dichlorvos (DIC) on hematological constituent [red blood corpuscles, white blood corpuscles (WBC), mean cell volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet counts, hemoglobin and hematocrite levels] and serum damage marker enzymes (aspartate aminotransferase, alanin aminotransferase, alkaline phosphatase, and lactate dehydrogenase) in rats at subacute period under laboratory conditions. DIC at dosages of 5 and 10 ppm was administered orally to six male rats ad libitum during the tests for 4 weeks consecutively. According to the results, DIC treatments increased significantly the levels of serum marker enzyme activities, whereas they did not change hematologic constituent except for WBC number treated with both dosages of DIC. The observations presented led us to conclude that the administrations of subacute DIC induced the levels of damage marker enzymes and leukocytosis. (C) 2008 Wiley Periodicals, Inc. Environ Toxicol 24: 128-132, 2009.
In Vitro Determination of 6pgd Enzyme Activity Purified From Lake Van Fish (Chalcalburnus Tarichii Pallas, 1811) Liver Exposed To Pesticides
(Springer, 2013) Guler, Muhammet; Kivanc, M. Riza; Turkoglu, Vedat; Basi, Zehra; Kivrak, Hilal
In the present study, the effect of methidathion, cypermethrin, and deltamethrin pesticides on Lake Van fish (Chalcalburnus tarichii Pallas, 1811) liver 6-phosphogluconate dehydrogenase enzyme activity was investigated due to the fact that these pesticides are extensively used to improve agricultural productivity in the Van region. 2',5'-ADP Sepharose 4B affinity chromatography was used to purify 6-phosphogluconate dehydrogenase enzyme from fish liver and SDS-PAGE technique was used to control the purity of this enzyme. The in vitro effect of methidathion, cypermethrin, and deltamethrin pesticides on the enzyme activity was investigated. The enzyme was purified 1,050-fold with specific activity of 27.04 EU/mg protein. Moreover, K-i constants of methidathion, cypermethrin, and deltamethrin were to be 3.294 +/- A 0.215, 0.718 +/- A 0.095, and 0.084 +/- A 0.009 mM respectively. The IC50 value were estimated as 9.95 x 10(-5) +/- A 0.1844 x 10(-5) mM for methidathion, 1.01 x 10(-4) +/- A 0.01413 x 10(-4) mM for cypermethrin, and 4.43 x 10(-6) +/- A 0.05653 x 10(-6) mM for deltamethrin. In conclusion, deltamethrin inhibits the enzyme activity more than methidathion and cypermethrin.
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.
In Vitro Effect of Oxidized and Reduced Glutathione Peptides on Angiotensin Converting Enzyme Purified From Human Plasma
(Elsevier Science Bv, 2019) Basi, Zehra; Turkoglu, Vedat
Angiotensin converting enzyme (ACE, peptidyldipeptidase A, EC 3.4.15.1) plays an important role in the regulation of blood pressure. In this study, ACE was purified from human plasma by affinity chromatography in single step. The enzyme purified in 5367-fold from human plasma and specific activity was found to be 1208 EU/mg protein. The purity and molecular weight of ACE were determined by SDS-PAGE, which indicated two bands at around 60 kDa and 70 kDa on the gel. Effect of oxidized glutathione (GSSG) peptide and reduced glutathione (GSH) peptide on purified ACE activity were also investigated in which lisinopril was used as reference inhibitor. GSSG showed activation effect on ACE activity whereas GSH provided inhibition effect. In the lights of activity (%) versus activator graph for GSSG and activity (%) versus inhibitor graphs for GSH and lisinopril; IC 50 values for GSH and lisinopril were determined to be 16.2 mu M and 0.781 nM, respectively. Type of inhibition for GSH and lisinopril from graph Lineweaver-Burk was found to be reversible non-competitive inhibition and K-i constants for GSH and lisinopril were calculated as 11.7 mu M and 0.662 nM, respectively.
In Vitro Effect of Some Plant Extracts on Acetylcholinesterase Enzyme In Human Erythrocytes and Serum
(Parlar Scientific Publications (p S P), 2013) Ozdemir, Alaattin; Turkoglu, Vedat; Demir, Halit
In this study, the effect of soluble extracts of five plants on the inhibition activity of acetylcholinesterase (AChE: E.C.3.1.1.7) enzyme were investigated. The results indicated that some of the plants achieved inhibition AChE which is an important enzyme for the nervous system of the human body. AChE catalyzes the hydrolysis of acetylcholine, a neurotransmitter substance which functions in certain parts of the nervous system. Ziziphora clinopodioides L., Chrysopthalmum montanum (DC.), Boiss. (Asteraceae), Melissa officinalis L. (Labiatae), Plantago (Plantaginaceae) lanceolata L. and Valeriana officinalis L. (Valerianaceae) plants are used for pharmacotherapeutic (cancer) aims by the people, in the east region of Turkey. In this study, the effect of soluble extracts of five plants on AChE activity was investigated in vitro. Cholinesterase activity was spectrophotometrically measured using acetylthiocholine iodide (AChI) as a substrate and dithiobis-nitrobenzoic acid (DTNB) as the coloring agent using different aliquots of the plant extracts. Ziziphora clinopodioides L. and Chrysopthalmum montanum were shown to have competitive inhibition on the erythrocyte, but Melissa officinalis L. and Plantago have shown noncompetitive inhibition effects on the erthrocyte. Melissa officinalis L. had shown non-competitive inhibition effects on the serum. The extracts of the five plants used in this study were found to inhibit AChE in the test at different concentrations. This study is the first one to show the relationships of erythrocyte and human serum AchE activity, in Labiatae family (Lamiaceae), Valeriana officinalis L. (Valerianaceae), Chrysophthalmum montanum, Ziziphora tenuior L., and lemon balm (Melissa officinalis).
In Vitro Inhibitor Effect and Molecular Docking of Thiamine (Vitamin B1), Riboflavin (Vitamin B2), and Reference Inhibitor Captopril on Angiotensin-Converting Enzyme Purified From Sheep Plasma
(Taylor & Francis Ltd, 2024) Ciftci, Muhammed Haluk; Turkoglu, Vedat; Bas, Zehra; Celikezen, Fatih Caglar
Objective: Angiotensin-converting enzyme (ACE, EC 3.4.15.1) is a very important factor in the regulation of blood pressure. Also, the inhibition of ACE with natural compounds has been a very important research area in the treatment of high blood pressure. ACE was purified and characterized from sheep plasma. Molecular docking studies and the inhibition effect of thiamine, riboflavin, and captopril on ACE were investigated. Methods: Herein, ACE was purified from sheep plasma by affinity chromatography. The effect of thiamine and riboflavin on ACE was researched. Molecular docking studies were performed to understand the molecular interactions between thiamine, riboflavin, and captopril with ACE. Results: The purification coefficient was found to be 8636 fold. The binding energy of thiamine, riboflavin, and captopril was found to be -6.7 kcal/mol, -8.1 kcal/mol, and -5.5 kcal/mol, respectively. Thiamine conformed to three conventional hydrogen bonds with ASP:415, HIS:513, and LYS:454. Riboflavin formed four conventional hydrogen bonds with GLN:281, GLU:376, THR:282, and TYR:520. Captopril formed two conventional hydrogen bonds with ARG:124, one conventional hydrogen bond with TYR:62 and ASN:85, and one carbon-hydrogen bond with ASN:66. Molecular docking results showed that thiamine, riboflavin, and captopril interacted with ACE through hydrogen bonding and hydrophobic interactions. Thiamine and riboflavin indicated significant inhibition effects on ACE. The IC50 values of thiamine, riboflavin, and captopril were found as 960.56 mu M, 11.02 mu M, and 1.60 nM, respectively. K-i values for thiamine, riboflavin, and captopril were determined as 1352.04 mu M, 12.30 mu M, and 1.06 nM, respectively. Conclusion: In this work, it was concluded that thiamine and riboflavin may have preventive and therapeutical impacts against high blood pressure with their ACE inhibitor effect. Thiamine and riboflavin showed a lower inhibitory effect with a higher IC50 than captopril. However, when the inhibitory effect of thiamine and riboflavin vitamins is compared to captopril, it is concluded that they may be natural inhibitors with fewer side effects.
Inhibition Effect of Thymoquinone and Lycopene Compounds on Glutathione Reductase Enzyme Activity Purified From Human Erythrocytes
(Taylor & Francis inc, 2022) Ciftci, Eser; Turkoglu, Vedat; Bas, Zehra
Glutathione reductase (GR, EC 1.8.1.7) is a specific antioxidant enzyme that catalyzes oxidized glutathione (GSSG) to reduced glutathione (GSH). GR enzyme maintains the cellular reduced GSH level and plays a central role in cell defense against reactive oxygen species. Herein, GR was purified with affinity chromatography method in one step using 2',5'-ADP Sepharose 4B from human erythrocytes. The purification rate of glutathione reductase enzyme purified from human erythrocytes was 6224 fold and specific activity was calculated as 9.586 EU/mg protein. The molecular weight of GR was determined to be 53 kDa by SDS-PAGE. The effect of thymoquinone and lycopene compounds on the GR activity purified from human erythrocytes was researched. Both compounds showed an inhibitory effect on GR activity. IC50 values for thymoquinone and lycopene were calculated as 62.12 mM and 35.79 mM, respectively. Inhibition type and Ki values were determined from the Lineveawer-Burk graph. The type of inhibition for thymoquinone and lycopene was found to be non-competitive inhibition. Ki value was calculated as 57.71 mM for thymoquinone and 46.65 mM for lycopene. In this study, it was concluded that antioxidant compounds thymoquinone and lycopene, which have an inhibitory effect on GR activity, may have a therapeutic effect on cancer disease.
The Inhibitory Effects of Lycopene and Thymoquinone on Angiotensin Converting Enzyme From Human Plasma (An in Vitro Study)
(Univ Karachi, 2022) Dede, Semiha; Turkoglu, Vedat; Bas, Zehra
Angiotensin converting enzyme (ACE, EC 3.4.15.1) is an important enzyme responsible for regulating blood pressure. Inhibition of this enzyme is an important treatment approach in the treatment of hypertension, and natural or synthetic ACE inhibitors are often used for this purpose. In this study, the preventive effect of two important antioxidant compounds, lycopene (LYC) and thymoquinone (TQ) on ACE activity in human plasma was investigated. Human plasma was used as ACE source. ACE activity was calculated absorbance at 345 nm after incubation for 30 minutes at 35 degrees C. TQ and LYC showed inhibitory effect on ACE activity. IC50 values for TQ and LYC were determined as 314 mu M and 182 mu M, respectively. Type of inhibition for TQ and lycopene from plot Line weaver-Burk was designated as noncompetitive inhibition. The Ki constants of TQ and LYC were determined to be 707 mu M and 167 mu M, respectively. It was concluded that TQ and LYC may have significant potential as ACE inhibitors.
The Investigation of Hawthorn (Crataegus Orientalis) Plant's Inhibition Effect on Angiotensin Converting Enzyme and in Silico Studies
(Taylor & Francis Ltd, 2024) Yavuz, Mahmut; Celikezen, Fatih Caglar; Firat, Mehmet; Bas, Zehra; Turkoglu, Vedat
Hawthorn plant is used among people due to its cardiovascular, anti-inflammatory, and antihistamine properties. But no scientific study has been done about Crataegus orientalis (Mill.) M.Bieb. The presented study was planned to determine the effects of ethanol and n-hexane extracts of Crataegus orientalis leaves on human plasma ACE enzyme. In the study, the effect of plant extracts on ACE was studied by the spectrophotometric method. The chemical composition of the plant extracts was determined by HPLC-DAD analyses. In addition, molecular doking and ADME prediction studies were carried out. As a result, the obtained data showed that Crataegus orientalis could have an important place in the pharmaceutical industry and drug discovery studies, as it supports the traditional use of Crataegus orientalis as hypotensive. The results of the molecular docking studies revealed that the interactions of the selected compounds with the human ACE enzyme caused inhibition. [GRAPHICS]
Investigation of in Vitro Effects of Polar and Nonpolar Extracts of Mountain Tea Plant (Sideritis Libanotica Subsp Linearis Labil) on Acetylcholinesterase Enzyme Within Human Serum and Erythrocytes
(Parlar Scientific Publications (p S P), 2017) Korkmaz, Serkan; Atasoy, Nurhayat; Turkoglu, Vedat; Yucel, Ufuk
In this study, the effects of body and root extracts of "Sideritis libanotica" plant over acetylcholinesterase (AChE: E.C.3.1.1.7) enzyme were investigated. Sideritis libanotica has been traditionally used to aid digestion, strengthen the immune system and suppress common cold, the flu, allergies and shortness of breath, sinus congestion, and even pain and mild anxiety. AChE catalyzes the hydrolysis of acetylcholine, a neurotransmitter substance which functions in certain parts of nervous system. When acetylcholine is hydrolyzed by AChE, the passage between the nerves ends. In diseases related to memory loss, it has been detected that acetylcholine is decomposed in a very short time. It has also been observed that inhibiting the enzyme that breaks down acetylcholine strengthens the passage between the nerves. In this study, human plasma and erythrocytes were used as enzyme sources and they were treated with methanol and hexane extracts of the plant's body and roots. Using acetylthiocholine iodide (AChI) as a substrate and dithiobisnitrobenzoic acid (DTNB) as a coloring agent, changes in esterase activity were spectrophotometrically measured. The results indicate that some forms of body and root extracts from the plant inhibit plasma and/or erithrocyte AChE. 150 values (concantrations where enzyme activity drops to %5o) for plant bodies' methanol and hexane extracts over plasma AChE activity was 1.066x10(-3) and 5.888x10(-3), respectively, while plant root's methanol extract's was 0.174x10(-3). Plant root's hexane extract had no inhibition effect on plasma AChE. On erithrocyte AChE levels, I-50 values for plant's body and root methanol extracts were 0.1679x10(-3) and 0.2136x10(-3), respectively. Neither body nor root hexane extracts had inhibitory effects on erithrocyte AChE levels.
Investigation of Inhibition Effect of Butanol and Water Extracts of Matricaria Chamomilla L. on Angiotensin-Converting Enzyme Purified From Human Plasma
(Wiley, 2022) Bas, Zehra; Turkoglu, Vedat; Goz, Yasar
Angiotensin-converting enzyme (ACE) liable for the regulation of blood pressure was purified from human plasma by affinity chromatography. Impact of water and butanol extracts of Matricaria chamomilla L. on purity ACE was examined. ACE was purified using the affinity chromatography method. The enzyme activity was evaluated at 345 nm by a . Extracts of M. chamomilla plant with butanol and water were prepared. Lisinopril was utilized as a specific inhibitor. ACE was purified 3,659-fold from human plasma and the specific activity was 1,350 EU/mg protein. The molecular weight and purity of ACE were found by SDS-PAGE and two bands of 60 and 70 kDa on the gel were detected. Water and butanol extracts of M. chamomilla demonstrated inhibitor impact on ACE activity. IC50 constants for water and butanol extracts of M. chamomilla were computed to be 1.292 and 0.353 mg/mL, respectively. The type of inhibition for whole inhibitors was identified as noncompetitive. IC50 and K-i constants for lisinopril were calculated to be 0.781 and 0.662 nM, respectively. These results indicate that butanol and water extracts of M. chamomilla may have an ACE inhibitor potential.
Investigation of the Effects of Natural Compounds Isolated From Arum Rupicola Var. Rupicola on Glutathione Reductase Enzyme Purified From Bovine Liver
(Wiley, 2019) Kivanc, Mehmet Riza; Turkoglu, Vedat
Glutathione reductase (GR, E.C. 1.8.1.7), a flavoenzyme, is responsible for recycling of oxidized glutathione disulfide. This study was performed in two main sections. In the first GR was purified from bovine liver by affinity column chromatography and the purification rate and specific activity of the enzyme were calculated as 1832-fold and 141 EU/mg protein, respectively. The subunit molecular weight of the enzyme was determined as 55 kDa by means of SDS-PAGE. The second section isolated natural components of Arum rupicola Boiss. var. rupicola using column chromatography. The isolation protocol for this plant was performed with a series of different-sized columns with hexane-ethyl acetate. According to the thin-layer chromatography plate, seven substances (R1-R7) were isolated. Our study's aim was to find new activators or inhibitors for GR activity. With this aim, all isolated substances were tested for GR activity. R6 showed competitive inhibition, while R4 had noncompetitive inhibition of GR activity. R1 played a role as an activator of GR activity. The inhibitory activity percentage vs. concentration graph was plotted. Values of IC50 for R4 and R6 were calculated as 0.193 mg/mL and 3.98 mu g/mL, respectively, from the equation of this graph.