Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2017/r/gumushane/11357
  A new colorimetric DPPH• scavenging activity method with no need for a spectrophotometer applied on synthetic and natural antioxidants and medicinal herbs

  Akar, Zeynep; Küçük, Murat; Doğan, Hacer

  2,2-Diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging, the most commonly used antioxidant method with more than seventeen thousand articles cited, is very practical; however, as with most assays, it has the major disadvantage of dependence on a spectrophotometer. To overcome this drawback, the colorimetric determination of the antioxidant activity using a scanner and freely available Image J software was developed. In this new method, the mixtures of solutions of DPPH• and standard antioxidants or extracts of common medicinal herbs were dropped onto TLC plates, after an incubation period. The spot images were evaluated with Image J software to determine CSC50 values, the sample concentrations providing 50% colour reduction, which were very similar with the SC50 values obtained with spectrophotometric method. The advantages of the new method are the use of lower amounts of reagents and solvents, no need for costly spectrophotometers, and thus significantly lowered costs, and convenient implementation in any environment and situation.

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• MakaleAçık Erişim2016/r/gumushane/10566
  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.

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• MakaleAçık Erişim2016/r/gumushane/15261
  Kinetic and in silico studies of hydroxy-based inhibitors of carbonic anhydrase isoforms I and II

  Ekhteiari Salmas, Ramin; Mestanoglu, Mert; Durdagi, Serdar; Sentürk, Murat; Kaya, A. Afşin; Kaya, Elif Çelenk

  A series of hydroxy and phenolic compounds have been assayed for the inhibition of two physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic human isozymes I and II. The investigated molecules showed inhibition constants in the range of 1.07-4003 and 0.09-31.5 μM at the hCA I and hCA II enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are compared using three different scoring algorithms, namely Glide/SP, Glide/XP and Glide/IFD. In addition, different ADME (absorption, distribution, metabolism and excretion) analysis was performed. All the examined compounds were found within the acceptable range of pharmacokinetic profiles.

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• MakaleAçık Erişim2016/r/gumushane/15059
  Synthesis of new 1,2,4-triazole compounds containing Schiff and Mannich bases (morpholine) with antioxidant and antimicrobial activities

  Ünver, Yasemin; Deniz, Sadik; Çelik, Fatih; Akar, Zeynep; Küçük, Murat; Sancak, Kemal

  Compound 2 was synthesized by reacting CS2/KOH with compound 1. The treatment of compound 2 with hydrazine hydrate produced compound 3. Then, compound 3 was converted to Schiff bases (4a–d) by the handling with several aromatic aldehydes. The treatment of triazole compounds 4a–d containing Schiff base with morpholine gave compounds 5a–d. All compounds were tested for their antioxidant and antimicrobial activities. The antioxidant test results of DPPH• radical scavenging and ferric reducing/antioxidant power methods showed good antioxidant activity. The triazole-thiol (3) was the most active, and the effect of the substituent type of the thiophene ring on the activity was same for both Schiff bases (4a–d) and Mannich bases (5a–d). Among the newly synthesized triazole derivatives, the Schiff base 4d and the Mannich base 5d carrying nitro substituent on the thiophene ring showed promising antibacterial and antifungal activity, with lower MIC values than the standard antibacterial ampicillin.

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• MakaleAçık Erişim2016/r/gumushane/13394
  Antioxidant 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.

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• MakaleAçık Erişim2016/r/gumushane/12992
  Antioxidant, 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.

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• MakaleAçık Erişim2016/r/gumushane/11391
  Investigation of the inhibitory properties of some phenolic standards and bee products against human carbonic anhydrase I and II

  Aygul, Imdat; Yaylaci Karahalil, Fatma; Supuran, Claudiu T.

  Polyphenols are important secondary products of plants with the potential to inhibit carbonic anhydrases. The aim of this study was to investigate the inhibition effects of various phenolic standards, honey, propolis, and pollen species on human carbonic anhydrase I and II. The inhibition values (IC50) of the phenolics (gallic acid, protocatechuic acid, quercetin, catechin, tannic acid, and chrysin) ranged from 0.009 to 0.32 μg/mL, tannic acid emerging as the best inhibitor. The inhibition values of three different types of honey, heather, rhododendron, and chestnut ranged between 2.32 and 25.10 μg/mL, the chestnut honeys exhibiting the best inhibition. The ethanolic extracts of pollen and propolis exhibited good inhibitory properties, with IC50 values between 0.486 and 3.320 μg/mL. In order to evaluate the phenolic composition of bee products, phenolic profiles and total phenolic contents (TFC) were also measured. The inhibition ranking among the natural products studied was phenolic standards > propolis > pollen > honeys, and inhibition was related to TFC.

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• MakaleAçık Erişim2015/r/gumushane/15760
  Acethylcholinesterase inhibitory potential and antioxidant properties of pyrogallol

  Ozturk Sarikaya, S. Beyza

  Pyrogallol is found naturally in crops and fruits of many plants. It is also an active ingredient of many pharmaceuticals. For this reason, we employed different in vitro antioxidant assays such as cupric ion Cu2+ reducing power, Fe3+ reducing power, total antioxidant activity by ferric thiocyanate method, ABTS radical scavenging, DMPD radical scavenging, DPPH • scavenging, Fe2+ chelating, O2•- scavenging and H2O2 scavenging activities of pyrogallol. Pyrogallol inhibited 77.95% lipid peroxidation of linoleic acid emulsion at 30 μg/mL concentration. BHA, BHT, α-tocopherol and trolox exhibited inhibitions of 89.88, 89.97, 83.82 and 91.85% against peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, pyrogallol was an effective of all the scavenging and reducing power results. In this study, pyrogallol was also evaluated as potential inhibitor for acethycholinesterse enzyme. The results showed that pyrogallol exhibited potent acetylcholinesteras inhibitory activity with IC50 and Ki values 10.2 and 8.6 μM, respectively.

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• MakaleYayıncıda açık erişim2015/r/gumushane/15457
  Inhibition profile of a series of phenolic acids on bovine lactoperoxidase enzyme

  Sarikaya, S. Beyza Ozturk; Sisecioglu, Melda; Cankaya, Murat; Gulcin, Ilhami; Ozdemir, Hasan

  Lactoperoxidase (LPO) catalyzes the oxidation of numerous of organic and inorganic substrates by hydrogen peroxide. It has very vital activity in the innate immune system by decreasing or stopping the activation of the bacteria in milk and mucosal secretions. This study's purpose was to investigate in vitro effect of some phenolic acids (ellagic, gallic, ferulic, caffeic, quercetin, p-coumaric, syringic, catechol and epicatechin) on the purified LPO. This enzyme was purified from milk by using different methods such as Amberlite CG-50 resin, CM-Sephadex C-50 ion-exchange and Sephadex G-100 gel filtration chromatography. LPO was purified 28.7-fold with a yield of 20.03%. We found phenolic acids have inhibition effects on bovine LPO enzyme to different concentrations. Our study showed lower concentrations of caffeic acid, ferulic acid and quercetin exhibited much higher inhibitory effect on enzyme, so these three of them were clearly a more potent inhibitor than the others were. All of compounds were non-competitive inhibitors.

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