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    Adsorption of cellulase on poly(2-hydroxyethyl methacrylate) cryogels containing phenylalanine
    (Tubitak Scientific & Technological Research Council Turkey, 2016) Yavuz, Murat; Cakir, Oguz; Baysal, Zubeyde
    The aim of this study was to prepare a supermacroporous cryogel that can be used for the adsorption of cellulase. The macroporous cryogel of poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-phenylalanine) [p(HEMA-MAPA)] was prepared by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with a functional monomer of N-methacryloyl-L-phenylalanine (MAPA). The cryogel was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and swelling tests. The effects of several parameters such as medium pH, temperature, ionic strength, and flow rate on cellulase adsorption were also investigated. Maximum cellulase adsorption was observed at 25 degrees C and pH 4.0. Furthermore, adsorbed cellulase was desorbed from the cryogel by using 1.0 M NaCl. The p(HEMA-MAPA) cryogel could be used many times without the cellulase adsorption capacity decreasing significantly.
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    Adsorption of cellulase on poly(2-hydroxyethyl methacrylate) cryogels containingphenylalanine
    (2016) Yavuz, Murat; Baysal, Zübeyde; Çakır, Oğuz
    The aim of this study was to prepare a supermacroporous cryogel that can be used for the adsorption ofcellulase. The macroporous cryogel of poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-phenylalanine) [p(HEMA-MAPA)] was prepared by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with a functional monomer of N-methacryloyl-l-phenylalanine (MAPA). The cryogel was characterized by scanning electron microscopy, Fourier transforminfrared spectroscopy, and swelling tests. The effects of several parameters such as medium pH, temperature, ionicstrength, and ow rate on cellulase adsorption were also investigated. Maximum cellulase adsorption was observedat 25◦C and pH 4.0. Furthermore, adsorbed cellulase was desorbed from the cryogel by using 1.0 M NaCl. Thep(HEMA-MAPA) cryogel could be used many times without the cellulase adsorption capacity decreasing significantly.
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    Antioxidant activities of ethanol extracts of Hypericum triquetrifolium and Hypericum scabroides
    (Taylor & Francis Ltd, 2008) Kizil, Goeksel; Kizil, Murat; Yavuz, Murat; Emen, Sevil; Hakimoglu, Fidan
    The antioxidative potential of ethanol extracts of Hypericum triquetrifolium Turra (Hypericaceae) and Hypericum scabroides Robson Poulter (Hypericaceae) were investigated for the first time using 1,1-diphenyl-2-picrylhydrazyl (DPPH), metal chelating, reducing power, hydroxyl radical, total antioxidant activity, and lipid peroxidation inhibition assays. Both extracts tested were found to be highly active in the DPPH radical scavenging assay. The IC50 values of H. triquetrifolium (HT) and H. scabroides (HS) in the DPPH radical scavenging assay were 39.0 and 33.8 mu g/mL, respectively. The amounts of total phenolic compounds were also determined, and total phenolic content of 1 mg H. triquetrifolium and H. scabroides ethanol extracts were equivalent to 267 and 333 mu g gallic acid. Metal chelating ability was found to be low compared with EDTA. Both ethanol extracts of Hypericum species exhibited a high reducing power, suggesting that extracts had strong electron-donating capacity. The degradation of deoxyribose by hydroxyl radicals was shown to be inhibited by Hypericum extracts, acting mainly by scavenging hydroxyl radicals rather than as chelators of iron ions. Total antioxidant activity of ethanol extracts of HT and HS were tested by using ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. Antioxidative activities of both extracts were found to be comparable with vitamin E. Moreover, both extracts showed notable capacity to suppress Fe2+-induced lipid peroxidation in rat brain homogenate. The results obtained in the current study indicate that ethanol extracts of HS and HT are a potential source of natural antioxidants.
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    Bio-active nanoemulsions enriched with gold nanoparticle, marigold extracts and lipoic acid: In vitro investigations
    (Elsevier Science Bv, 2014) Guler, Emine; Barlas, F. Baris; Yavuz, Murat; Demir, Bilal; Gumus, Z. Pinar; Baspinar, Yucel; Coskunol, Hakan
    A novel and efficient approach for the preparation of enriched herbal formulations was described and their potential applications including wound healing and antioxidant activity (cell based and cell free) were investigated via in vitro cell culture studies. Nigella sativa oil was enriched with Calendula officinalis extract and lipoic acid capped gold nanoparticles (AuNP-LA) using nanoemulsion systems. The combination of these bio-active compounds was used to design oil in water (O/W) and water in oil (W/O) emulsions. The resulted emulsions were characterized by particle size measurements. The phenolic content of each nanoemulsion was examined by using both colorimetric assay and chromatographic analyses. Two different methods containing cell free chemical assay (1-diphenyl-2-picrylhydrazyl method) and cell based antioxidant activity test were used to evaluate the antioxidant capacities. In order to investigate the bio-activities of the herbal formulations, in vitro cell culture experiments, including cytotoxicity, scratch assay, antioxidant activity and cell proliferation were carried out using Vero cell line as a model cell line. Furthermore, to monitor localization of the nanoemulsions after application of the cell culture, the cell images were monitored via fluorescence microscope after FITC labeling. All data confirmed that the enriched N. sativa formulations exhibited better antioxidant and wound healing activity than N. sativa emulsion without any enrichment. In conclusion, the incorporation of AuNP-LA and C officinalis extract into the N. sativa emulsions significantly increased the bio-activities. The present work may support further studies about using the other bio-active agents for the enrichment of herbal preparations to strengthen their activities. (C) 2014 Elsevier B.V. All rights reserved.
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    Bioapplications of polythiophene-g-polyphenylalanine-covered surfaces
    (Wiley-V C H Verlag Gmbh, 2015) Güler, Emine; Akbulut, Hüseyin; Bozokalfa, Guliz; Demir, Bilal; Eyrilmez, Gizem Oyman; Yavuz, Murat; Demirkol, Dilek Odacı; 0000-0003-3452-8551; 0000-0003-2381-9775; 0000-0003-1642-3481
    The fabrication of electro and bioactive surfaces by electrochemical deposition of the thiophene-functionalized polyphenylalanine macromonomer (T-g-PPhe) is reported. The resulting conducting graft copolymer, polythiophene-graft-polyphenylalanine (PT-g-PPhe) formed on the indium tin oxide (ITO) glass surface, is characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and fluorescence microscopy. Then, possible uses of PT-g-PPhe as matrices in the sensor design for both electrochemical biosensing and cell adhesion studies are investigated. In the first part, PT-g-PPhe that is deposited on ITO is further functionalized with the arginylglycylaspartic acid peptide via 1-Ethyl-3-(3 dimethylaminopropyl) carbodiimide for the selective cell adhesion. Immunofluorescence staining is performed to detect the difference between adherences of integrin alpha v beta 3 receptor positive (U87-MG) and negative (HaCaT) cell lines on to the biofunctional surface. In the second part, an electrochemical glucose sensor is constructed by immobilizing glucose oxidase on the surface of PT-g-PPhe, which is deposited on a glassy carbon electrode.
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    Biological affinity evaluation of Lawsonia inermis origin Lawsone compound and its radioiodinated form via in vitro methods
    (Springer, 2015) Tekin, Volkan; Muftuler, F. Zumrut Biber; Guldu, Ozge Kozgus; Kilcar, Ayfer Yurt; Medine, E. Ilker; Yavuz, Murat; Unak, Perihan
    WST-1-based cytotoxicity assay of lawsone (LW) was performed on MCF7, Caco2, BJ and Keratinocyte cells and viabilities were found as over 90 % for all cells. Significant wound healing effect of LW was reported on Keratinocyte cells. Antibacterial and antifungal activities of LW were tested on seven microorganisms with three concentrations and 1,000 A mu g/disc of LW showed antibacterial effect on Bacillus subtilis. In vitro cell incorporation of radioiodinated LW (I-131-LW) was evaluated on same cells. Keratinocyte cells uptake were 5 times more. Consequently, I-131-LW was found usable for researches about especially skin diseases in addition to breast and intestinal cancer.
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    A case study on in vitro investigations of the potent biological activities of wheat germ and black cumin seed oil
    (Tubitak Scientific & Technological Research Council Turkey, 2015) Ag Seleci, Didem; Gumus, Zinar Pinar; Yavuz, Murat; Seleci, Muharrem; Bongartz, Rebecca; Stahl, Frank; Coskunol, Hakan
    The objectives of this study were to investigate the potential biological activities of black cumin seed oil (BCSO) and wheat germ oil (WGO) on different cell lines. Initially, commercially available BCSO and WGO obtained by supercritical carbon dioxide extraction were analyzed in terms of tocopherol, aliphatic alcohols, and thymoquinone content via HPLC and GC analysis. Cell free antioxidant activities and total phenolic content of both oils were detected by DPPH assay and Folin-Ciocalteu method, respectively. As well as the DPPH assay, the protective effect against reactive oxygen species (ROS) was determined by microscopic observation of ROS generation in NIH-3T3 cells with or without oil samples by using an oxidation-sensitive fluorescent dye, H2DCFDA. Cytotoxicity was assessed using an MTT assay. In the case of BCSO, after exposing cells to 0.025-1.0 mg/mL and 1.0-100 mu g/mL concentrations for 24 h, the IC50 values of BCSO were 0.58, 0.51, 0.47, and 0.36 mg/mL for NIH-3T3, A549, U87, and HeLa cells, respectively. On the other hand, concentrations of WGO lower than 0.1 mg/mL did not cause a decrease in cell viability for all cell lines. Apoptotic and necrotic rates of these cell lines were investigated via flow cytometry. BCSO also exhibited proliferative efficacy for NIH-3T3 cells.
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    Comparison of the effects of maternal protein malnutrition and intrauterine growth restriction on redox state of central nervous system in offspring rats
    (Elsevier, 2007) Tatli, Mehmet; Guzel, Aslan; Kizil, Goksel; Kavak, Vatan; Yavuz, Murat; Kizil, Murat
    Both maternal protein malnutrition and intrauterine growth restriction (IUGR) have deleterious effects on brain development, but a comparison of these effects has not been previously reported. The objectives of this study were to investigate and compare the effects of both factors on the oxidative status of the central nervous system (CNS), including the spinal cord, in offspring rats. We evaluated various parameters of oxidative status and antioxidant enzyme activities of superoxide dismutase and catalase (CAT) in different regions of the CNS from 60-day-old rats subjected to prenatal and postnatal protein restrictions [middle protein restriction 12%, severe protein restriction (SPR) 4%] or IUGR produced by uterine artery ligation. Furthermore, we compared these study groups to each other and to control rats fed an isocaloric 24% protein diet. Results were analyzed using one-way ANOVA followed by Tukey's post hoc test. Both protein restrictions and IUGR altered various parameters of oxidative status. In all evaluated structures, protein restrictions resulted in increases in thiobarbituric acid-reactive substances level and index of lipid peroxidation (P < 0.001), and in decreases in antioxidant enzyme activities (P < 0.005). IUGR also increased lipid peroxidation levels in the blood samples (P < 0.04) and protein oxidative damage in the cerebellum and cerebral cortex (P < 0.005); however, no effects were detected on the spinal cord. The greatest decrease in CAT activity was in the cerebellum of rats fed with SPR diet (P < 0.001). This study suggests that not only severe but also middle protein malnutrition have deleterious effects on CNS structures, including the spinal cord. Protein restriction has a greater effect on the redox state of the CNS than IUGR. (c) 2007 Elsevier B.V. All rights reserved.
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    CTAB modified dellite: A novel support for enzyme immobilization in bio-based electrochemical detection and its in vitro antimicrobial activity
    (Elsevier Science Sa, 2016) Maiga, Mohomodou; Yalcinkaya, Esra Evrim; Sonmez, Burak; Puglia, Debora; Yavuz, Murat; Demirkol, Dilek Odaci; Kenny, Jose M.
    A novel support material for enzyme immobilization based on cetyltrimethylammonium bromide modified Dellite (CTAB-Del) was successfully synthesized and used to manufacture pyranose oxidase (PyOx) biosensors (CTAB-Del/PyOx). The intercalation of CTAB into Dellite was confirmed by FTIR, XRD and TGA techniques. PyOx was immobilized onto the glassy carbon electrode, via glutaraldehyde crosslinking, by using CTAB-Del as a support. In order to test the analytical performance of CTAB-Del/PyOx biosensors, chronoamperometric measurements were carried out using three electrodes configurations, at a constant potential of 0.7 V in working buffer, under stirring, with successive addition of glucose. The linear response for CTAB-Del/PyOx biosensor ranged from 0.01 to 0.50 mM with an equation of y=4.42x+0.004 (R-2=0.998), and the limit of detection for glucose was calculated to be 0.081 pM (S/N = 3). In order to confirm its practical use, the CTAB-Del/PyOx biosensor was also applied for glucose measurement in various beverages. In addition, the antimicrobial activities of Del and CTAB-Del were screened in vitro by means of the disc diffusion susceptibility test, selecting a yeast, three different Gram-positive, and five different Gram-negative bacteria. The obtained results showed a moderate antibacterial activity of CTAB-Del against Gram-positive bacteria. (C) 2016 Elsevier B.V. All rights reserved.
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    Effects of maternal protein malnutrition and intrauterine growth restriction on redox state of the central nervous system in offspring rats
    (Wiley-Liss, 2007) Tatli, Mehmet; Guzel, Aslan; Kizil, Goksel; Kavak, Vatan; Yavuz, Murat; Kizil, Murat
    [Abstract Not Available]
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    Electrochemical deposition of polypeptides: bio-based covering materials for surface design
    (Royal Soc Chemistry, 2014) Akbulut, Huseyin; Yavuz, Murat; Guler, Emine; Demirkol, Dilek Odaci; Endo, Takeshi; Yamada, Shuhei; Timur, Suna
    A simple and efficient approach for the electrochemical deposition of polypeptides as bio-based covering materials for surface design is described. The method involves N-carboxyanhydride (NCA) ring-opening polymerization from its precursor to form a thiophene-functionalized polypeptide macromonomer (T-Pala), followed by electropolymerization. The obtained conducting polymer, namely polythiophene-g- polyalanine (PT-Pala), was characterized and utilized as a matrix for biomolecule attachment. The biosensing applicability of PT-Pala was also investigated by using glucose oxidase (GOx) as a model enzyme to detect glucose. The designed biosensor showed a very good linearity for 0.01-1.0 mM glucose. Finally, the antimicrobial activities of newly synthesized T-Pala and PT-Pala were also evaluated by using the disc diffusion method.
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    Enginarın Atık Kısımlarının Biyolojik Aktivite Güdümlü Olarak Fraksiyonlandırılması ve Etkin Fraksiyonların Antioksidan, Antimikrobiyal ve Hücre Kültürü Etkinliğinin Artırılmasına Yönelik Uygulamalar
    (2017) Barlas, Fırat Barış; Yılmaz, Tülay Şengel; Yılmaz, Yahya Yasin; Odacı, Dilek Demirkol; Yavuz, Murat
    [Abstract Not Available]
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    Herbal infusions of black seed and wheat germ oil: Their chemical profiles, in vitro bio-investigations and effective formulations as Phyto-Nanoemulsions
    (Elsevier Science Bv, 2015) Gumus, Z. Pinar; Guler, Emine; Demir, Bilal; Barlas, F. Baris; Yavuz, Murat; Colpankan, Dilara; Senisik, A. Murat
    The reported studies related to black seed oil (BSO) and wheat germ oil (WGO) have illustrated that they have a wide range of biological activities. Therefore, enhancing the amount of bio-active compounds that caused higher cell based anti-oxidative effect as well as cell proliferation, etc. in seed oils, infusion of crude plant material has been gained importance as a traditional technique. Herein, we accomplished the infusion of Calendula flowers that also contains many phyto-constituents into BSO and WGO. After the infusion of oils, the change of phytochemical amount was investigated and evaluated according to the oils by chromatography, radical scavenging activity. Subsequently, for investigating the biological impact upon live cells, cytotoxicity, cell-based antioxidant capacity, wound healing and radioprotective activity were tested with monkey kidney fibroblast like cells (Vero) and HaCaT keratinocytes. In vitro cell based experiments (wound healing and radioprotective activity) confirmed that Calendula infused BSO and WGO have greater bio-activity when compared to those plain forms. The herbal oils prepared with an effective extraction technique were incorporated into nanoemulsion systems which will be then called as 'Phyto-Nanoemulsion'. After herbal oil biomolecules were encapsulated into nanoemulsion based delivery systems, the designed formulations were investigated in terms of biological activities. In conclusion, these preparations could be a good candidate as a part of dermal cosmetic products or food supplements which have the therapeutic efficiency, especially after radio- or chemotherapy. (C) 2015 Elsevier B.V. All rights reserved.
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    Immobilization of ?-amylase via adsorption onto bentonite/chitosan composite: Determination of equilibrium, kinetics and thermodynamic parameters
    (Wiley-V C H Verlag Gmbh, 2014) Baysal, Zübeyde; Bulut, Yasemin; Yavuz, Murat; Aytekin, Çetin
    Immobilization of -amylase onto bentonite/chitosan (BC) composite was studied via adsorption. The composite was characterized by FTIR, SEM, and surface area measurements. The effect of different factors such as, pH, temperature, initial enzyme concentration, and various thermodynamic parameters was determined. The maximum -amylase adsorption capacity of the BC composite was determined as 64mg/g at 0.8mg/mL enzyme concentration. The activity of the immobilized enzyme was measured under varying experimental conditions. The highest enzyme activity for free and immobilized enzyme was determined at 30 and 35 degrees C in 0.1M phosphate buffer at pH 7.0. The effect of substrate concentration on enzyme activity of free and immobilized enzymes showed a good fit to the Lineweaver-Burk plots. Michaelis constant, K-m, for the immobilized -amylase was found to be higher than for the free enzyme. The adsorption isotherm was modeled by the Langmuir equation.
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    In Vitro Antimicrobial and Antioxidant Activity of Ethanol Extract of Three Hypericum and Three Achillea Species From Turkey
    (Taylor & Francis Inc, 2011) Baris, Deniz; Kizil, Murat; Aytekin, Cetin; Kizil, Goksel; Yavuz, Murat; Ceken, Bircan; Ertekin, A. Selcuk
    The present study was conducted to determine the antimicrobial, antifungal and antioxidant activity of the ethanol extract of Hypericum scabrum L (HSm), Hypericum lysimachioides var. lysimachioides (HL), and Hypericum retusum Aucher (HR) and ethanol extracts of Achillea aleppica D.C. subsp. aleppica (AA), Achillea aleppica D.C. subsp. zederbaueri (Hayek) Hub.-Mor (AZ), and Achillea biebersteinii Afan. (AB). The antioxidant properties of extracts were evaluated using different antioxidants tests, including reducing power, free radical scavenging, deoxyribose assay, metal chelating activities and determination of total phenolic compounds. The extracts obtained from Hypericum and Achillea species showed high antioxidant properties. The protective effects of plant extracts were compared with a well known antioxidant, Butilated Hydroxytoluen (BHT) and -tocopherol. Total antioxidant activity of ethanol extracts of plants were also tested by using ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. Antioxidative activities of plant extracts were found to be comparable with Vitamin E. The results showed that the ethanol extracts of all tested plant exhibited different activity against tested microorganisms. Since most of the studied extracts have good antimicrobial and antioxidant activity, it might be possible to use them as natural food additives that act both as antioxidants and as spices.
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    Lokal Streptomyces türlerinin sekonder metabolitlerinin izolasyonu, yapılarının aydınlatılması ve biyolojik aktivitelerinin araştırılması
    (2016) Yavuz, Murat; Kızıl, Murat; İnce Yılmaz, Ebru
    Son yıllarda yeni hastalıkların gelişmesi ve mevcut antibiyotiklere karşı dirençli mikroorganizma türlerinin ortaya çıkması nedeniyle, bakteriyel ve fungal enfeksiyonlar insan sağlığını küresel ölçekte tehdit etmektedir. Bu durum yeni biyolojik aktif metabolitlerin keşfini zorunlu kılmaktadır. Mikrobiyal sekonder metabolitler, potansiyel olarak sahip oldukları özel yapıları ve biyolojik aktiviteleri ile doğal bileşiklerin zengin kaynaklarından birini teşkil ederler. Actinomycetales ordusuna dahil olan Streptomyces türleri, çoğu biyolojik olarak aktif olan sekonder metabolitleri üretebilme özelliğine sahip yetenekli mikroorganizmalardır. Bu mikroorganizmalardan izole edilen ve ticari öneme sahip sekonder metabolitlerden başlıcaları antibakteriyel, antifungal ve antitümör ajanlardır. Yeni biyoaktif metabolitlerin keşfi için Streptomyces gibi iyi bilinen ve yetenekli mikroorganizmalarda yeni bileşiklerin taranması temel stratejilerden biridir. Bu amaçlar doğrultusunda, endemik bitkilerin kök çevresi topraklarından izole edilip 16S rRNA genleri kullanılarak teşhisleri yapılmış olan 67 Streptomyces ve 1 Nocardiopsis türünün ham ve farklı organik çözücülerdeki ekstraktlarının Gram-pozitif, Gram-negatif bakterilerin ve Candida albicans mayasının üremesi üzerine etkisi in vitro olarak test edildi. Biyolojik aktivite temelli ön-tarama işlemleri sırasında denenen bu 68 türden 25 kadarının test mikroorganizmalarının üremeleri üzerinde engelleyici etkiye sahip olduğu belirlendi. Biyolojik olarak aktif olan bu türlerin ham ekstraktlarının, İTK kromatogramlarının çeşitli renklendirici reaktiflerden yararlanılarak belirlendiği kimyasal taramalar sonucunda ilgi çekici türler belirlendi. Optimum üretim koşullarında yeteri miktarda sekonder metabolit elde etmek için biyolojik ve kimyasal taramalar sonucu tespit edilen Streptomyces sp. BA2, Streptomyces sp. AA50, Streptomyces sp. BS40 ve Streptomyces sp. AS42 kodlu ilgi çekici türlerden büyük ölçekte üretildi. Elde edilen metabolit ekstraktlara, kolon kromatografisi, İTK, PİTK, moleküler elek kromatografisi ve HPLC gibi çeşitli kromatografik teknikler uygulanarak saf bileşikler izole edildi. 1H NMR ve 13C NMR teknikleri başta olmak üzere 2D NMR (COSY, HSQC, HMBC gibi) ile UV, IR ve MS gibi spektroskopik tekniklerin yanında AntiBase, Doğal Ürünler Sözlüğü ve Chemical Abstract gibi veri bankaları kullanılarak saflaştırılan sekonder metabolitlerin yapıları aydınlatıldı. Streptomyces sp. BA2'den bilinen bileşikler olan, aktinomisin D (170), monensin B (171) ve monensin A (172) karışımı ile bis(2-etilhegzil)ftalat (173) saflaştırılıp yapıları aydınlatıldı. Klinik olarak bazı kanser türlerinin tedavisinde kullanılan aktinomisin D (170) ile doğal polieter iyonofor antibiyotikler olduğu bilinen monensin B (171) ve A (172) karışımının test mikroorganizmalarının üremesi üzerine antimikrobiyal aktivitesi test edildi. Aktinomisin D (170) ve monensin B (171) ve A (172) karışımının yüksek antimikrobiyal aktivite sergilediği belirlendi. Streptomyces sp. AA50'den, daha önce bazı Streptomyces türlerinden izole edildiği rapor edilmiş olan chrysophanol (175) ile 2-acetylchrysophanol (178) ve daha önce çeşitli bitkilerden izole edilmiş olan fakat ilk kez bu çalışmada bir mikrorganizmadan izole edilen chrysophanol-10,10'-bianthron (174) bileşikleri saflaştırıldı. Ayrıca endotelin reseptör antagonisti oldukları bilinen siklik pentapeptit A (179) ve siklik pentapeptit B (180) bileşikleri karışım halinde izole edildi. İzole edilen bu bileşiklerden chrysophanol-10,10'-bianthron (174) ve chrysophanol (175)'un DPPH radikal söndürme aktivitesi, indirgeme gücü gibi antioksidan özelliklerinin yanında ayrıca agaroz jel elektroforezi kullanılarak bu bileşiklerin DNA'yı OH radikaline karşı koruma aktivitesi ile DNA'yı prooksidan olarak kesim aktivitesi araştırıldı. Streptomyces sp. BS40'tan ise carbazomycin G (182) ile bilinen bileşik olan teleocidin B2 (183) ve izomer (184) karışımı ile iki yeni teleocidin türevi olan 14-O-acetylteleocidin B2 (195) ve 14-O-acetylteleocidin B2 izomer (196) karışımı izole edildi. Çalışmalar esnasında, ciltte güçlü iritasyona ve vezikül oluşumuna neden olduğu görülen 14-O-acetylteleocidin B2 (195) ve izomer (196) karışımının Artemia salina L. larvaları üzerine 0,1-10 µg/mL konsantarasyon aralığında % 100 sitotoksik aktivite sergilediği tespit edildi. Streptomyces sp. AS42'den ise, endotelin reseptör antagonisti oldukları bilinen ve bu çalışmada ayrıca AA50 suşundan da izole edilmiş olan siklik pentapeptit A (179) (siklo(-D-Glu-L-Ala-D-Val-L-Leu-D-Trp-) ve siklik pentapeptit B (180) (siklo(-D-Glu-L-Ala-allo-D-Ile-L-Leu-D-Trp-) bileşikleri izole edilerek yapıları 1D ve 2D NMR tekniklerinin yanında HPLC-ESI-MS2/MS3 tekniği kullanılarak aydınlatıldı. Anahtar Kelimeler : Streptomyces, Doğal ürünler, Sekonder metabolit izolasyonu, Yapı aydınlatması, Antimikrobiyal aktivite, Antioksidant aktivite.
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    Molecular characterization of rhizospheric soil streptomycetes isolated from indigenous Turkish plants and their antimicrobial activity
    (Springer, 2008) Yilmaz, Ebru Ince; Yavuz, Murat; Kizil, Murat
    As part of a research program whose aim is to determine the diversity of streptomycetes in order to discover new bioactive secondary metabolites, rhizosphere soils of three indigenous plants were analyzed. A total of 55 actinomycetes were isolated using three different medium from the samples. The rhizospheric soil of the plant Aethionema dumanii gave the highest number of actinomycetes, i.e., 42% versus 27% and 31% for the soils from Salvia aytachii and Achillea ketenoglui, respectively. The AIA is the most favorable medium for the isolation of the actinomycetes from different rhizospheric soils. 16S rDNA sequence analysis revealed that while some isolates belong to different cluster groups such as Streptomyces lydicus, S. rochei, S. microflavus, S. griseoflavus, S. albidoflavus and S. violaceusniger, the majority of the sequences did not considerable clustered with the member of different Streptomyces groups. The in vitro antimicrobial activities of the crude organic and aqueous extracts of isolates were screened using a disc diffusion assay against a panel of bacteria and C. albicans. A total of 22 isolates showed antimicrobial activity. The antibacterial action of the extracts is more pronounced on Gram-positive than on Gram-negative bacteria in most cases. About 18% of the actinomycetes showed also antifungal activity. Study of the influence of two different culture media on production of bioactive molecules showed that the higher antimicrobial activity was obtained in M2 when compared to TSB. The results from this study provide evidence that the streptomycetes in the rhizosphere soils could be promising sources for antimicrobial bioactive agents.
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    Niosomes of Nerium oleander extracts: In vitro assessment of bioactive nanovesicular structures
    (Elsevier, 2017) Gunes, Aybike; Guler, Emine; Un, Rabia Nur; Demir, Bilal; Barlas, F. Baris; Yavuz, Murat; Coskunol, Hakan
    Niosomes are known as non-ionic surfactant-based vesicles and have been used quite a lot for medical applications as a novel drug delivery system in recent years. Herein we describe, the preparation and characterization of niosomes containing oleander (Nerium oleander) (ONs) extract as the herbal compound. In this context, niosomal formulations of two different extracts obtained from oleander roots were prepared by a thin film hydration technique using Tween 60 (non-ionic surfactant) with a cholesterol mixture at 1:1 M ratio. These vesicular structures were characterised by various techniques such as atomic force microscopy, zeta potential and dynamic light scattering size measurements. ONs vesicles are less than 100 nm in size with a good physical stability more than 50 days. Initially, total phenolic and flavonoid contents and antioxidant activities of the extracts were investigated. The methanol extract of oleander roots (MOE) showed higher polyphenolic content and exhibits a better antioxidant activity in compared to the hydro-methanol (20% methanol) extract (MOWE). Total phenolic contents in the MOE and MOWE were calculated as 64.51 +/- 0.945 mu g/mg and 65.05 +/- 0.37 mu g/mg gallic acid equivalents, respectively. Encapsulation efficiencies of the vesicles were found as 16.2% for MON (contain MOE) and 13.24% for MWON (contain MOWE). The significant linear correlation Was confirmed between the antioxidant activity and total phenolic content of extracts as well as ONs. Cell based cytotoxic activities of methanol extract and MON formulations were also assessed via KIT assay using Hela and A549 cell lines. (C) 2016 Elsevier B.V. All rights reserved.
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    p-Cymene based organometallic ruthenium(II)-arene complexes with benzaldehyde derived thiosemicarbazones: synthesis, characterization and antimicrobial activity
    (Dicle Üniversitesi Tıp Fakültesi, 2017) Yavuz, Murat; Yaman, Pelin Köse; Öztürk, Nurdan; Timur, Suna; Subaşı, Elif
    Objective: Thiosemicarbazone (TSC) containing three new mononuclear ruthenium(II)-arene complexes were synthesized so as to contribute to the development of ruthenium complexes with pharmacologically attracted properties.Methods: Reactions of the ruthenium(II)-arene dimer [{RuCl(μ-Cl)(η6-p-cymene)}2] (1) with the respective TSC1-3 (1:2 molar ratio) in methanol resulted in p-cymene containing new conformationally rigid half-sandwich organometallic ruthenium(II)-arene complexes; [(η6-p-cymene)Ru(TSC1-κ3O,N,S)]Cl (I), [(η6-p-cymene)Ru(Cl)(TSC2-κ2N,S)]Cl (II), and [(η6-p-cymene)Ru(Cl)(TSC3- κ2N,S)]Cl (III). The molecular structures of complexes I, II and III were elucidated on the spectroscopic data obtained by the application of 1H NMR, Fourier transform infrared (FT-IR), UV-vis and elemental analysis techniques. In vitro antimicrobial activities of the synthesized three ruthenium(II)-arene complexes were evaluated using the disc diffusion method. Results: The spectroscopic data indicated that TSC1 was bounded to the metal as a tridentate ligand with its thione sulfur atom, phenolic oxygen atom and azomethine nitrogen atom in the complex I, while TSC2 and TSC3 were bounded to metal center as bidentate manner through their thione sulfur atom and imine nitrogen (C=N) atom in the complexes II and III, respectively. The obtained antimicrobial activity results showed that these complexes efficiently inhibit the growth of Gram-positive bacterial strains. Conclusion: The TSC1-3 containing ruthenium(II)-arene complexes were successfully synthesized and their molecular structures were also determined by the spectroscopic methods. All ruthenium(II)-arene complexes showed higher antibacterial activities against Gram-positive bacterial strains than the Gram-negative ones.