Sürdürülebilir Kalkınma Amaçları

Yazarlar

  • MakaleAçık Erişim2018
    Purification 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 Erişim2017
    Novel 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.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2016
    9,10-Dibromo-N-aryl-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones: Synthesis and Investigation of Their Effects on Carbonic Anhydrase Isozymes I, II, IX, and XII

    Göksu, Haydar; Topal, Meryem; Keskin, Ali; Gültekin, Mehmet S.; Çelik, Murat; Gülçin, Ilhami; Tanc, Muhammet; Supuran, Claudiu T.

    N-substituted maleimides were synthesized from maleic anhydride and primary amines. 1,4-Dibromo-dibenzo[e,h]bicyclo-[2,2,2]octane-2,3-dicarboximide derivatives (4a-f) were prepared by the [4+2] cycloaddition reaction of dibromoanthracenes with the N-substituted maleimide derivatives. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the new derivatives were assayed against the human (h) isozymes hCA I, II, IX, and XII. All tested bicyclo dicarboximide derivatives exhibited excellent inhibitory effects in the nanomolar range, with Ki values in the range of 117.73-232.87 nM against hCA I and of 69.74-111.51 nM against hCA II, whereas they were low micromolar inhibitors against hCA IX and XII. A series of 9,10-dibromo-N-aryl-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones (4a-f) were synthesized from N-substituted maleimide derivatives and 9,10-dibromoanthracene. Compounds 4a-f were assayed against human carbonic anhydrases (hCA) IX and XII, which are the two tumor-associated isozymes, and hCA I and II, which represent the most common off-targets for the development of selective anticancer CA inhibitors.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2016
    Acetylcholinesterase 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.

  • MakaleAçık Erişim2015
    N-Acylsulfonamides strongly inhibit human carbonic anhydrase isoenzymes i and II

    Yildirim, Alper; Atmaca, Ufuk; Keskin, Ali; Topal, Meryem; Çelik, Murat; Gülçin, Ilhami; Supuran, Claudiu T.

    Sulfonamides represent a significant class of biologically active compounds that inhibit carbonic anhydrase (CA, EC.: 4.2.1.1) isoenzymes involved in different pathological and physiological events. Sulfonamide CA inhibitors are used therapeutically as diuretic, antiglaucoma, antiobesity and anticancer agents. A series of new sulfonamides were synthesized using imides and tosyl chloride as starting materials. These N-acylsulfonamides efficiently inhibited the cytosolic human carbonic anhydrase isoenzymes I, and II (hCA I, and II), with nanomolar range inhibition constants ranging between 36.4 ± 6.0-254.6 ± 18.0 and 58.3 ± 0.6-273.3 ± 2.5 nM, respectively.