Yazar "Kizil, M." seçeneğine göre listele
Listeleniyor 1 - 6 / 6
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe DNA CLEAVAGE PROTECTING ACTIVITY AND IN VITRO ANTIOXIDANT POTENTIAL OF AQUEOUS EXTRACT FROM FRESH STEMS OF RHEUM RIBES(Akademiai Kiado Zrt, 2013) Tanrikut, S. Emen; Ceken, B.; Altas, S.; Pirinccioglu, M.; Kizil, G.; Kizil, M.Rheum ribes L. (Polygonaceae) is a common species of rhubarb in Turkey, which is also found in Iraq, Iran, Pakistan, Afghanistan, and Russia. The antioxidant potency of stems was investigated employing various in vitro systems, such as lipid peroxidation in rat brain homogenate, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radical scavenging, ferric reducing power, metal chelation activity. R. ribes stem parts showed strong inhibitory activity toward lipid peroxidation of rat brain homogenate induced by the FeCl3-ascorbic acid system. R. ribes extract was able to reduce the stable free radical DPPH 83.9+/-1.90% at 150 mu g ml(-1). The reducing power of the extract was 0.46+/-0.074 at 250 mu g ml(-1). The effect of extract of R. ribes on DNA cleavage induced by UV-photolysis of H2O2 using pBluescript M13+ plasmid DNA was also investigated. This extract significantly inhibited DNA damage induced by reactive oxygen species (ROS). These findings demonstrate that aqueous extract from fresh stems of R. ribes has antioxidant activity and thus have great potential as a source for natural health products.Öğe Evaluation of antioxidant activity of ethanol extract of Hypericum retusum and its protective effect on protein oxidation(Wiley-Blackwell, 2009) Ceken, B.; Kizil, G.; Yavuz, M.; Kizil, M.[Abstract Not Available]Öğe Evaluation of Silybum marianum seed extract and vitamin B6 derivatives on methylglyoxal and sugar-induced oxidative DNA damage(Akademiai Kiado Zrt, 2023) Inceoren, N.; Toptanci, B. Ceken; Kizil, G.; Kizil, M.Reducing sugars are known to generate reactive oxygen species (ROS), mainly by means of the glycation reaction. The hydroxyl radical, a prominent entity of ROS, is known to alter cellular DNA and induces damage to DNA, and plays a role in diseases such as diabetes mellitus. In this study, the oxidative damage of DNA induced by the lysine/Fe3 thorn /MG reaction was investigated. Silybum marianum seeds extract (SlyE), standard silymarin (Sly), and vitamin B6 derivatives, pyridoxal-5-phosphate (PLP), pyridoxamine (PM), and pyridoxine (P) in reversing glycation-induced damage in DNA were evaluated. In addition, different sugars and sugar phosphates were incubated with plasmid pBR 322 DNA to control and compare their harmful effects. Our results revealed that SlyE protected lysine/Fe3 thorn /MG induced oxidative DNA damage more effectively than Sly. Vitamins, on the other hand, prevented this DNA damage in the order of PLP>P>PM. The DNA altering and damaging intensity of sugars and sugar phosphates tested increased considerably in the following order: Ribose-5-phosphate > fructose-6-phosphate > ribose > fructose > fructose-1,6 biphosphate > glucose-6 phosphate > glucose. The results show that the lysine/Fe3 thorn /MG glycation reaction can cause oxidative damage of DNA through a mechanism involving hydroxyl radicals. It also provides evidence that ribose-5-phosphate and fructose and its phosphate metabolites can alter DNA more rapidly in vitro than glucose and its phosphate metabolites.Öğe Phytochemical analysis, antioxidant, antimicrobial, anticholinesterase and DNA protective effects of Hypericum capitatum var. capitatum extracts(Elsevier Science Bv, 2016) Boga, M.; Ertas, A.; Eroglu-Ozkan, E.; Kizil, M.; Ceken, B.; Topcu, G.This is the first study on phytochemical analysis and biological evaluation of Hypericum capitatum Choisy var. capitatum (HCC) endemic to Turkey with exception of essential oil analysis. Hyperoside and isoquercetin (25.7 +/- 0.02 and 17.8 +/- 0.02 mu g/mg extract, respectively) were determined as the main compounds of the methanol extract. The major compounds of essential oil of HCC were found to be spathulenol and iso-longifolene (12.9% and 11.2%, respectively), and linoleic and palmitic acids (26.8% and 18.3%, respectively) were the main fatty acids. The methanol extract whose antioxidant activities studied for the first time was found to have moderate activity in beta-carotene bleaching method (IC50: 41.69 +/- 1.29 mu g/mL) and was found to be the most active extract in scavenging of DPPH free radical (IC50: 16.82 +/- 0.58 mu g/mL) and ABTS cation radical (IC50: 9.24 +/- 0.28 mu g/mL) and CUPRAC assays. Among the prepared four extracts of HCC, the methanol extract showed highest activity against Escherichia coli with an MIC value of 10 mu g/mL, and the methanol extract was also found to have high DNA damage protective activity. The methanol extract exhibited high butyrylcholinesterase inhibitory activity (70.74%). Thus, H. capitatum var. capitatum can be regarded as a potential natural antioxidant, antimicrobial, anticholinesterase source and DNA damage inhibitor. (C) 2016 SAAB. Published by Elsevier B.V. All rights reserved.Öğe PROTECTIVE ACTIVITY OF ETHANOL EXTRACT OF THREE ACHILLEA SPECIES AGAINST LIPID PEROXIDATION, PROTEIN OXIDATION AND DNA DAMAGE IN VITRO(Akademiai Kiado Zrt, 2010) Kizil, M.; Kizil, G.; Yavuz, M.; Ceken, B.The present study was designed to investigate the protective ability of the ethanol extracts of Achillea aleppica D.C. subsp. aleppica (AA), Achillea aleppica D.C. subsp. zederbaueri (Hayek) Hub.-Mor (AZ) and Achillea biebersteinii A fan. (AB) against the lipid peroxidation, protein oxidation and DNA damage induced by Fenton system. Ethanol extract of Achillea species were evaluated by quantifying the ability of different concentrations of plant extracts to supress Fe2+-induced lipid peroxidation in rat liver homogenates. The inhibition of lipid peroxidation by ethanol extracts of AA, AB and AZ was the result of their scavenging effect on Fe2+/ascorbate generated free radicals. The ability of AA, AZ and AB to prevent oxidative damage to bovine serum albumin (BSA) induced by Fe3+/H2O2 and ascorbic acid was investigated. The ethanol extracts of AA, AB and AZ at different concentrations (50-1000 mu g ml(-1)) efficiently prevented protein oxidation induced by hydroxyl radical as assayed by protein oxidation markers including protein carbonyl formation (PCO). We have also investigated the effect of ethanol extracts of AA, AB and AZ on DNA cleavage induced by UV-photolysis of H2O2 using pBluescript M13+ plasmid DNA. These extracts significantly inhibited DNA damage induced by reactive oxygen species (ROS). Therefore, Achillea aleppica D.C. subsp. aleppica (AA), Achillea aleppica D.C. subsp. zederbaueri (Hayek) Hub.-Mor (AZ) and Achillea biebersteinii Afan. extracts may be useful in the food industry as effective synthetic antioxidants.Öğe Synthesis and DNA-cleaving activity of a series of substituted arenediazonium ions(Maik Nauka/Interperiodica/Springer, 2008) Ceken, B.; Kizil, M.We investigated the reactions of substituted aryl radicals and aryl cations derived from arenediazonium ions and their ability to cause cleavage of supercoiled DNA and their tendency toward free radical or cation formation in the presence and absent of copper (I) chloride. It was found that the substituted arenediazonium salts can cleave supercoiled DNA to the open circular form II DNA and linear form III DNA. Results methodical studies indicate that both carbon-centered radicals and aryl cations participate in the cleavage pathways.
