Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2018Antidiabetic Potential: Effect of Resorcinol on α-Glycosidase and α-Amylase Enzymes
Topal, Fevzi
The vast majority of the carbohydrates in the biomolecule class are formed by photosynthesis using sunlight. One of the important enzymes in this class is α-glycosidase. This enzyme converts complex carbohydrates to monosaccharides. On the other hand, another important enzyme species is the α-amylase enzyme. Which directly related to starch. Starch is a type of polymer formed by the oxygen binding of glucose units to each other at the C1 position with glycosidic bonds. α-Amylase is an enzyme that catalyzes the hydrolysis of glycosidic bonds in starch, and this enzyme is purified from a wide variety of animals, plants, and microorganisms. Resorcinol, a phenol derivative, is an important organic chemical substance in the production of textile, medicine, hair dye, plastic and agricultural products of many industrial materials. Resorcinol, a phenol derivative, is present as white crystals, and resorcinol consists of two hydroxyl molecules attached to the benzene ring, and also was defined as α-glycosidase and α-amylase inhibitor to detect antidiabetic properties. Resorcinol was used as 𝛼-glycosidase and 𝛼-amylase inhibitor. Accordingly, IC50 values of α-amylase and α-glycosidase were calculated as 1.34 μM and 77.00 nM, respectively. On the other hand, Ki value for α-glycosidase was found as 30.16 nM. It has been observed that α-amylase and α-glycosidase enzymes can inhibit by resorcinol compound. It has the properties of inhibiting carbohydrate absorption by inhibiting α-glycosidase enzymes in the small intestine. For both metabolic enzymes, resorcinol may be preferred as an inhibitor. In this case, resorcinol may be used as an inhibitor against to healty problems like Diabetes mellitus and antiobesity.
- MakaleAçık Erişim2018Purification and selected biochemical properties of peroxidase from cress (Lepidium sativum sub sp. sativum)
Altay, Ahmet; Koktepe, Tubanur; Durmaz, Lokman; Topal, Fevzi; Gülçin, İlhami; Köksal, Ekrem
Cress (Lepidium sativum) is an annual herb from Brassicaceae family, and in some regions. It is known as peppergrass, garden cress, garden pepper-cress, pepperwort, or poor man’s pepper. Cress is an important medicinal plant in some countries including Turkey. This plant has major scientific and therapeutic significance. Peroxidase (POD, E.C.1.11.1.7) is an oxidor-eductase enzyme produced by a number of organisms. In this study, POD enzyme was purified from cress by ammonium sulphate precipitation, gel filtration, and CM-Sephadex ion-exchange chromatographies. K m and V max values were calculated from the Lineweaver-Burk graph for H 2 O 2 and guaiacol substrates and the substrate specificity of POD was investigated. The results showed that substrate specificity of H 2 O 2 is better than substrate specificity of guaiacol for this enzyme. The inhibition effects of three cations (Al 3+ , Cu 2+ , and Cr 3+ ) and one organic compound of cetyl trimethylammonium bromide were performed and their inhibition types were determined. Finally, optimum pH, optimum temperature, optimum ionic strength, and stable pH were determined.
- MakaleAçık Erişim2017Novel eugenol derivatives: Potent acetylcholinesterase and carbonic anhydrase inhibitors
Topal, Fevzi; Gulcin, Ilhami; Dastan, Arif; Guney, Murat
Eugenol was used as starting material to obtain some phenolic compounds. The synthesis of these phenolic compounds was performed in a two-step procedure. The structures of the formed products (novel eugenol derivatives 1–6) have been determined on the basis of NMR spectroscopy and other spectroscopic methods. The compounds were tested in terms of carbonic anhydrase (CA) inhibition potency. Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes, which catalyse the reaction between carbon dioxide (CO2) and water (H2O), to generate bicarbonate (HCO3−) and protons (H+). CO2, HCO3− and H+ are essential molecules and ions for many important physiologic processes occurring in all living organisms. Acetylcholinesterase (AChE, E.C.3.1.1.7) is found in high concentrations in the red blood cells and brain. Novel eugenol derivatives (1–6) were tested for the inhibition of two cytosolic CA isoforms I, and II (hCA I, and II) and AChE. These compounds demonstrated effective inhibitory profiles with Ki values in ranging of 113.48-738.69 nM against hCA I, 92.35-530.81 nM against hCA II, and 90.10-379.57 nM against AChE, respectively. On the other hand, acetazolamide clinically used as CA inhibitor, shoed Ki value of 594.11 nM against hCA I, and 120.68 nM against hCA II, respectively. Also, AChE was inhibited by tacrine as an AChE inhibitor at the 71.18 nM level.
- MakaleAçık Erişim2016Antioxidant activity of taxifolin: An activity-structure relationship
Topal, Fevzi; Nar, Meryem; Gocer, Hulya; Kalin, Pinar; Kocyigit, Umit M.; Gülçin, Ilhami; Alwasel, Saleh H.
Taxifolin is a kind of flavanonol, whose biological ability. The objectives of this study were to investigate the antioxidants and antiradical activities of taxifolin by using different in vitro bioanalytical antioxidant methods including DMPD•+, ABTS•+, and DPPH•-scavenging effects, the total antioxidant influence, reducing capabilities, and Fe2+-chelating activities. Taxifolin demonstrated 81.02% inhibition of linoleic acid emulsion peroxidation at 30 μg/mL concentration. At the same concentration, standard antioxidants including trolox, α-tocopherol, BHT, and BHA exhibited inhibitions of linoleic acid emulsion as 88.57, 73.88, 94.29, and 90.12%, respectively. Also, taxifolin exhibited effective DMPD•+, ABTS•+, and DPPH•-scavenging effects, reducing capabilities, and Fe2+-chelating effects. The results obtained from this study clearly showed that taxifolin had marked antioxidant, reducing ability, radical scavenging and metal-chelating activities. Also, this study exhibits a scientific shore for the significant antioxidant activity of taxifolin and its structure-activity insight.
- MakaleAçık Erişim2016Antioxidant, antiradical, and anticholinergic properties of cynarin purified from the Illyrian thistle (Onopordum illyricum L.)
Topal, Meryem; Gocer, Hulya; Topal, Fevzi; Kalin, Pinar; Köse, Leyla Polat; Gulçin, Ilhami; Çakmak, Kader C.; Küçük, Murat; Durmaz, Lokman; Gören, Ahmet C.
Cynarin is a derivative of hydroxycinnamic acid and it has biologically active functional groups constituent of some plants and food. We elucidated the antioxidant activity of cynarin by using different in vitro condition bioanalytical antioxidant assays like DMPD•+, ABTS•+, DPPH• and H2O2 scavenging effects, the total antioxidant influence, reducing capabilities, Fe2+ chelating and anticholinergic activities. Cynarin demonstrated 87.72% inhibition of linoleic acid lipid peroxidation at 30 g/mL concentration. Conversely, some standard antioxidants like trolox, tocopherol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) exhibited inhibitions of 90.32, 75.26, 97.61, 87.30%, and opponent peroxidation of linoleic acid emulsion at the identical concentration, seriatim. Also, cynarin exhibited effective DMPD•+, ABTS•+, DPPH•, and H2O2 scavenging effects, reducing capabilities and Fe2+ chelating effects. On the contrary, IC50 and Ki parameters of cynarin for acetylcholinesterase enzyme inhibition were determined as 243.67 nM (r2: 0.9444) and 39.34 ± 13.88 nM, respectively. This study clearly showed that cynarin had marked antioxidant, anticholinergic, reducing ability, radical-scavenging, and metal-binding activities.
- MakaleAçık Erişim2016Acetylcholinesterase and carbonic anhydrase isoenzymes I and II inhibition profiles of taxifolin
Gocer, Hulya; Topal, Fevzi; Topal, Meryem; Küçük, Murat; Teke, Dilek; Gülçin, Ilhami; Alwasel, Saleh H.; Supuran, Claudiu T.
Taxifolin, also known as dihydroquercetin, is a flavonoid commonly found in plants. Carbonic anhydrase (CA, EC 4.2.1.1) plays an important role in many critical physiological events including carbon dioxide (CO2)/bicarbonate (HCO3-) respiration and pH regulation. There are 16 known CA isoforms in humans, of which human hCA isoenzymes I and II (hCA I and II) are ubiquitous cytosolic isoforms. In this study, the inhibition properties of taxifolin against the slow cytosolic isoenzyme hCA I, and the ubiquitous and dominant rapid cytosolic isoenzyme hCA II were studied. Taxifolin, as a naturally bioactive flavonoid, has a K-i of 29.2nM against hCA I, and 24.2nM against hCA II. For acetylcholinesterase enzyme (AChE) inhibition, K-i parameter of taxifolin was determined to be 16.7nM. These results clearly show that taxifolin inhibited both CA isoenzymes and AChE at the nM levels.
- MakaleYalnız künye2014Synthesis and carbonic anhydrase inhibitory effects of novel sulfamides derived from 1-aminoindanes and anilines
Akbaba, Yusuf; Bastem, Enes; Topal, Fevzi; Gülçin, Ilhami; Marasç, Ahmet; Göksu, Süleyman
Three 1-aminoindanes, four anilines and BnOH or t-BuOH were reacted with chlorosulfonyl isocyanate to give sulfamoyl carbamates. Pd-C catalysed hydrogenolysis reactions of carbamates or deprotection of the Boc group of the carbamates with CF3CO2H afforded seven novel sulfamides. Human carbonic anhydrase (hCA) isoenzymes I and II (hCA I and hCA II) were purified from fresh human blood erythrocytes with onestep affinity chromatography on Sepharose 4B-tyrosine-sulfanilamide. The inhibitory properties of the novel sulfamides on both isoenzymes were determined using the esterase activity with 4-nitrophenyl acetate (NPA) as substrate. The tested novel sulfamides derived from 1-aminoindanes and anilines effectively inhibited hCA I and II competitively in the nanomolar range. Among these compounds, the novel sulfamide derivative 17 showed themost potent inhibitory effect against hCA I (Ki: 153.88 nM), while sulfamide derivative 26 showed the highest inhibitory potential against hCA II (Ki: 117.80nM).
- MakaleAçık Erişim2014Oxidation of cyanobenzocycloheptatrienes: Synthesis, photooxygenation reaction and carbonic anhydrase isoenzymes inhibition properties of some new benzotropone derivatives
Güney, Murat; Coskun, Ahmet; Topal, Fevzi; Dastan, Arif; Gülçin, Ilhami; Supuran, Claudiu T.
The oxidation of some cyanocycloheptatrienes with CrO3 and pyridine was investigated and a few new nitrile functionalised benzotropone derivatives were obtained. Photooxygenation reaction of these products was also studied. The structures of the formed products were determined on the basis of NMR spectroscopy and the formation mechanism of unusual products was discussed. Human carbonic anhydrase isoenzymes I, and II (hCA I and hCA II) inhibition properties of nitrile functionalized new benzotropone derivatives were also studied. Both CA isozymes were inhibited in the low micromolar range by these nitrile functionalized benzotropone analogues. The newly synthesized benzotropone derivatives showed inhibition constants in the sub-micromolar range (2.51-4.06 mu M). The best hCA I inhibition was observed in 5H-benzocycloheptene-7-carbonitrile (K-1: 2.88 +/- 0.86 mu M). On the other hand, 5-oxo-5H-benzocycloheptatriene-7-carbonitrile showed the powerful inhibitory effect against hCA II (K-i: 2.51 +/- 0.34 mu M). (C) 2014 Elsevier Ltd. All rights reserved.
- MakaleYalnız künye2011Polyphenol contents and antioxidant properties of medlar (Mespilus germanica L.)
Gülçin, Ilhami; Topal, Fevzi; Sarikaya, S. Beyza Öztürk; Bursal, Ercan; Bilsel, Gökhan; Gören, Ahmet C.
Medlar is the fruit of Mespilus germanica L. in the family of Rosaceae. The present study outlines that the native medlar (Mespilus germanica L.) fruits an extremely rich source of antioxidants. In this study, antioxidant and antiradical property of medlar fruits were evaluated. Total phenolics and flavonoids amounts in lyophilized extract of medlar (LEM) fruits were calculated as gallic acid and quercetin equivalents, respectively. Antioxidant and radical scavenging activity of LEM were investigated using different in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH·), N,N-dimethyl-p-phenylenediamine (DMPD•+), and superoxide anion radicals (O2•-) scavenging activity, hydrogen peroxide (H2O2), ferric ions (Fe 3+) and cupric ions (Cu 2+) reducing ability, Fe 3+ -TPTZ reducing ability, ferrous ions (Fe2+) chelating activity as trolox equivalent. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid and ascorbic acid in LEM were detected by high performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). The presence of these antioxidant compounds can be considered as a quality parameter for edible medlar fruits.
- MakaleAçık Erişim2011In vitro inhibition of α-carbonic anhydrase isozymes by some phenolic compounds
Öztürk Sarikaya, Sevim Beyza; Topal, Fevzi; Şentürk, Murat; Gülin, Ihami; Supuran, Claudiu T.
Carbonic anhydrase inhibitors (CAIs) are a class of pharmaceuticals used as antiglaucoma agents, diuretics, antiepileptics, in the management of mountain sickness, gastric and duodenal ulcers, neurological disorders or osteoporosis. We report here the inhibitory capacities of some phenolic compounds against three human CA isozymes (hCA I, hCA II, and hCA VI) and the gill carbonic anhydrase of the teleost fish Dicentrarchus labrax (European seabass) (dCA). The isozymes showed quite diverse inhibition profiles with these compounds. These data may lead to design novel CAIs with a diverse inhibition mechanism compared to sulfonamide/sulfamate inhibitors.