Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Synthesizing of Olive Leaf Exteact Loaded Calcium Alginate Chitosan Microcapsules and Investigation of Their Anticancer Activity on Cancer Cells(Izmir Institute of Technology, 2014) Bal, Yıldız; Şanlı Mohamed, Gülşah; Bayraktar, OğuzAs we all know there are too many diseases which can be counted as fatal. But cancer is one of the most terrifying one for human race. Moreover, breast cancer in females and lung cancer in males are the most common cancer types. Although there are so many treatment methods, they have severe side effects. On the other hand, mother earth is so willing to give her hand and open all of the sources she got. O. europaea is one of the most important valuable source and Mediterranean area is blessed with that source. Olive and olive products may play an important role in cancer prevention. However, there are some limitations on their direct usage. Since encapsulation technology can seal valuable things into small capsules, it can be used to alleviate these limitations. In this study, the aim was figure the limitations of olive leaf extract (OLE) out with the encapsulation technology and enhance the effectiveness. Moreover, assess this effectiveness on cancer cell lines. Thus, OLE loaded calcium alginate (OLE-Ca-Alg) capsules produced by ionic-crosslinking. To limit the loss of OLE, capsules were coated with chitosan (CS) and OLE loaded chitosan calcium alginate (OLE-CS-Ca-Alg) were produced–two stage procedure. Optimization studies and characterization of the microcapsules were carried out. To investigate their anticancer effectiveness cytotoxicity, cell cycle and apoptosis analysis were performed for lung and breast cancer cell lines besides cytotoxic effects of the capsules were compared with healthy cell line. Additionally, visual observations were done by optical microscopy. Consequently, results showed OLE loaded capsules are more cytotoxic than free OLE. These effects were supported with cell cycle, apoptosis analysis and optical microscopy observations. In contrast none of compounds was cytotoxic for healthy cells. Thus, it can be concluded that our results will enhance the drug industry as it is a new approach for anticancer drugs and biocompatible material for biomedical applications.Master Thesis Development of Biosensors for Determination of the Total Antioxidant Capacity(Izmir Institute of Technology, 2008) Çoban, Seçil; Bayraktar, OğuzIn this study, an amperometric laccase biosensor was developed for determination of the oleuropein concentration that is the biological active component of olive leaf and contributes dominantly to the total antioxidant capacity. The biosensor was prepared by immobilization of laccase from Trametes versicolor by addition of cross-linking agent, glutaraldehyde, into the carbon paste electrode. Different biosensors were prepared by changing the amount of crosslinking agent and concentration of the enzyme solution. So, effect of these parameters on biosensor performance was investigated. The best biosensor performance was determined for the biosensor having glutaraldehyde amount of 12.03 % vol. of the biosensor bottom part and 5 mg/ml of laccase enzyme. The effect of scan rate and temperature on the biosensor performance was also investigated in this study. The scan rate of 10 mV/s was decided to be the optimum for the amperometric detection of oleuropein considering the fastest response and maximum reduction current. 250C was chosen as an optimum temperature value due to the maximum laccase activity and capability of oleuropein acting as an antioxidant. Extraction of phenolics from olive leaf was also an important part of this study. The extract was divided into fractions varying in their oleuropein amounts such as polar fractions and relatively less polar fractions. Therefore, biosensor performance was investigated for fractions containing different type of phenolics. HPLC analyses of the fractions were also performed in this study. In addition total phenol content and antioxidant capacity of the fractions were determined by conventional methods.Master Thesis Alcohol Dehydrogenase and Aldehyde Dehydrogenase Gene Polymorphism in Turkish Alcohololic People and Control Group(Izmir Institute of Technology, 2007) Salman, Esin; Bayraktar, OğuzIn this study, alcohol dehydrogenase and aldehyde dehydrogenase gene, encoding alcohol metabolizing enzymes, polymorphisms were determined in alcoholic and nonalcoholic determination methods. The main objective in the study was to investigate the relationship of ADH2, ADH3 and ALDH2 gene polymorphism with the tendency of Turkish people to develop alcohol tolerance. The other significant objective was to compare polymorphism types of ADH2, ADH3 and ALDH2 seen in Turkish people and other ethnic groups or races in the world. In this present study, ADH3 genotypes of 141 alcoholic subjects, and also ADH2 and ALDH2 genotypes of 156 alcoholic subjects were assigned. The control group consisted of 80 healthy non-drinkers. Three different SNP genotyping methods were used in this study. ADH3 genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism method (RFLP-PCR). ADH2 genotyping was performed by allele specific primer extension method and ALDH2 genotyping was performed by multiplex PCR by using two allele specific primer pairs. The ADH2.1 genotype was the most common type of all ADH2 genotypes in both alcoholic and non alcoholic groups. However, there was no significant difference between alcoholic and non alcoholic groups for ADH2 genotyping.ADH3 genotyping of both groups suggested that the ADH3.2 genotype frequency was higher than ADH3.1. ADH3.2 was found to be more prevalent in alcoholics compared to control group, suggesting that alcoholics were more tolerant to alcohol. In all of the alcoholic and non-alcoholic subjects examined, the frequency of ALDH2.1 was found to be 100%. Finally,it can be inferred from that obtained results, ADH2 genetic variations seem not to be related to alcoholism. On the other hand, ADH3 and ALDH2 genetic variations can make Turkish people susceptible to alcohol dependency. If all the results are taken into consideration, it is inferred that Turkish people have the inherited variations of ADH and ALDH genes which do not protect them to have alcohol sensitivity and dependency. Obtained results in the study are consistent with the white race in the world including European people but not consistent with Oriental people as expected.Master Thesis Development of Natural Compound-Loaded Nanofibers by Electrospinning(Izmir Institute of Technology, 2010) Balta, Ali Bora; Bayraktar, OğuzIn this study, the crude silk which is obtained from silkworm was turned into a silk solution after a serial procedure. Then, regenerated silk (foam) was obtained. The regenerated silk was dissolved in formic acid and polymer solution was prepared. After, nanofibers were produced by electrospinning. On the other hand, the content and antimicrobial activities of some plants were analyzed. Then all three forms of silk was absorbed with the olive leaf extract and extract desorption tests were done. As the first step of the study, the analyses of extracts which were obtained from four different plants were done. For this, total phenolic content and antioxidant capacity were found. In addition, minimum inhibition concentration (MIC) test and disc diffusion test were made for all extracts to Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa bacteria and Candida albicans fungi in order to determine their antimicrobial activity. While producing nanofibers from silk polymer with electrospinning method, different parameters such as concentration, voltage and distance were examined. Morphological characterization of nanofibers was done by scanning electron microscope (SEM). According to the results, the nanofiber with an optimum value which has a suitable diameter and structure was selected. With this nanofiber, the absorption and desorption tests of natural compound were made. The results were obtained by High pressure liquid chromatography (HPLC). Same adsorption and desorption tests were done also with the microfiber silk and regenerated silk (foam). As a result, it was shown by the controlled experiments that nanofibers were better for adsorption and desorption of natural compound when compared to microfiber silk and regenerated silk. In conclusion, nano-sized silk fibroin structures can be adsorbed with natural compounds in order to gain functionality. Using this kind of biofunctional products as medical textile and wound dressing material will be more advantageous when compared to current wound dressing materials.Master Thesis Encapsulation of Sarcopoterim Spinosum Extract in Zein Perticle by Using Electrospray Method(Izmir Institute of Technology, 2013) Süngüç, Ceren; Bayraktar, OğuzSarcopoterium spinosum species has valuable and common medicinal plant in the Mediterranean region. The optimum conditions for the extraction of S. spinosum leaves to obtain bioactive extract were investigated using response surface methodology (RSM). Total phenol contents, total antioxidant and antibacterial activities, phenolic composition of S. spinosum extract were studied. The prepared S. spinosum extract showed high antioxidant activity when compared with many other medicinal plants in the literature. It was determined as 3143.5 mmole Trolox per gr dry weight. The phenolic content of S. spinosum extract was examined with High Performance Liquid Chromatography (HPLC). Hyperoside and isoquercetin were detected in S. spinosum extract. Especially, isoquercetin was the major compound in the extract. In addition, the antimicrobial activity of S. spinosum extract was investigated. The extract showed fungicide activity against Candida albicans. S. spinosum extract were encapsulated within zein particle via electrospray method in order to enhance its stability. The effects of process parameters for electrospraying method on the particle morphology and size distribution were extensively investigated. The best process conditions were determined as zein concentration of 5% (w/v) in 70% aqueous ethanol solution, flow rate of 0.3 ml/h and applied voltage of 14 kV depending on narrow size distribution, spherical and smooth particle morphology. The best S. spinosum extract loading was achieved at extract to zein weight ratio of 1:5. The prepared extract loaded zein microparticles showed significant antioxidant activity.Master Thesis Preparation and Characterization of Silk Fibroin Based Materials Loaded With Natural Compounds(Izmir Institute of Technology, 2010) Şamlı, Merve; Bayraktar, OğuzIn this study, it was aimed to increase solubility of flavonoids via inclusion complexation. Silk was also selected as carrier material. Firstly we have prepared cyclodextrin inclusion complexes with rutin via co-precipitation method. Stability constant of Beta-cyclodextrin complex was calculated as 262 M-1. Aqueous solubility of rutin was increased with inclusion complex of Beta-Cyclodextrin. Effect of temperature on aqueous solubility of free rutin, and its complex were studied. Also solubility energies are calculated. Characterization of cyclodextrin complexes were conducted with the help of UV-visible spectroscopy, X-Ray Diffractometry, Differential Scanning Calorimetry, Thermal Gravimetric Analysis, Fourier Transform Infrared spectroscopy and Scanning Electron Microscobe techniques. Characterization results supported formation of inclusion complexes which were compatible with the previous literature studies. Before release tests, dissolution profile of rutin, physical mixture and inclusion complex was observed at 37.C and in PBS; results show that addition of cyclodextrin has an increasing effect on solubility rate and amount. Then silk fibroin based films were prepared and used as carriers for natural compounds. After loading flavonoids and complexes into silk fibroin based films, release tests were done at 37 .C in neutral pH conditions for 24 hours. Most of the Rutin .independent from the form, whether free or complexed- released from Silk Fibroin films within the first 5 hours (burst release occurs) and the rest of it released slowly within 24 hours. Electron microscobe analyses showed that films have a homogenous and dense morphology. Consequently, silk fibroin is useful to load natural compounds into silk fibroin films in order to modify their release period within physiological conditions.Master Thesis Screening of Some Plant Species for Their Total Antioxidant and Antimicrobial Activities(Izmir Institute of Technology, 2008) Kaçar, Diren; Bayraktar, OğuzIn this study aqueous/ethanol extracts of 42 plant species collected from same geographic region (Karaburun/İzmir) were screened for their relative total phenol contents, total antioxidant and antibacterial activities. In the first part of the study, Folin- ciocalteu assay and PCL (Photochemiluminescence) method were performed to detect the total phenol contents and total antioxidant activities of extracts, respectively.It was detected that the Hypericum empetrifolium had the highest activities for both water soluble and lipid soluble antioxidants and Sarcopterium spinosum has the highest result for total phenol assay as 635.26 GAEqmg/g sample.In order to detect the antibacterial activities of extracts a preliminary screening study was performed by using disc diffusion method. Out of the 42 plant species tested, 26 species exhibited antibacterial activities by inhibiting one or more microorganisms.Microdilution assays by 96 well plates were applied for the most active species to find out their minimum inhibition concentrations (MICs). The most promising plant species in the study, having the antibacterial activities were determined as H. empetrifolium, P.terebinthus, Arbutus unedo, and C. parviflorus.In this study there is a clear relationship between the analysis results and S.spinosum is one of the most noteworthy species in this study showing the highest total phenol content and important biological activities which has never been examined scientifically before. In that manner this study also presents new potential species that can be used as natural raw materials in some related industries.Master Thesis Adsorption of Olive Leaf Antioxidants on Silk Fibroin(Izmir Institute of Technology, 2006) Bayçın Hızal, Deniz; Bayraktar, OğuzThis study focused on producing protein based functional food with antioxidative and antimicrobial properties by adsorption of olive leaf antioxidants on silk fibroin. In accordance with this aim, extraction and adsorption of two most abundant polyphenols in olive leaves, oleuropein and rutin were studied. Furthermore, desorption studies were performed to increase the purity of polyphenols.In this study, effect of various parameters on extraction and adsorption were investigated by HPLC and antioxidant analyses. The adsorption isotherms of oleuropein and rutin were plotted at different temperatures, pH values and solid-liquid ratios. After adsorption, the adsorbed polyphenols on silk fibroin was subjected to SEM, FTIR, color, antioxidant and antimicrobial analyses to observe the changes in the silk fibroin.The experimental data of adsorption isotherms were well-fitted to Langmuir model. The maximum adsorption capacity was determined as 108 mg oleuropein/g silk fibroin and 21 mg rutin/g silk fibroin. In desorption process, 81% of rutin and 85 % of oleuropein were removed from the adsorbent surface in 70 % aqueous ethanol solution.After adsorption of oleuropein and rutin, the antioxidant capacity of silk fibroin increased from 1.93 mmol TEAC/g to 3.61 mmol TEAC/g. Silk fibroin also gained antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae after adsorption of olive leaf antioxidants. Desorbed polyphenols exhibited higher antioxidant capacity than the same amount of olive leaf extract due to the increase in the purity of oleuropein and rutin after desorption.Consequently, silk fibroin is a promising protein for the production of functional food or dietary supplements and for the purification of oleuropein and rutin.Master Thesis Inhibition of Catechol-0 (comt) Enzyme Activity by Some Plant-Derived Alkaloids and Phenols(Izmir Institute of Technology, 2009) Yalçın, Dilek; Bayraktar, OğuzIn this study, inhibition potentials of harmal seed alkaloids and olive leaf polyphenols were investigated on COMT catalyzed methylation reaction. Inhibition performances of natural alkaloids and polyphenolics whose purities were attempted to be increased by extraction and fractionation were compared with standards of these compounds and the best known COMT inhibitor, 3,5-dinitrocatechol. COMT enzyme inhibition experiments were performed with sentitive fluorometric method. In this method, Km values for SAM and aesculetin substrates were found as 3.5 + 0.3 uM and 6.4 + 0.4 uM, respectively. As a result of the inhibition study, the highest inhibitory effect is observed for harmine and harmaline rich fractions among harmal seed alkaloids. Inhibition constants indicating degree of competitiveness and noncompetitiveness (Ki and aKi) of the harmine fraction which has the highest inhibition performance were calculated as 0.15±0.07 ug/ml and 1.28±0.06 ug/ml, respectively.In the studies performed with standards of olive leaf polyphenols, while it was observed that rutin has inhibitory effect, oleuropein was found less effective. However, oleuropein rich fraction of olive leaf extract showed higher inhibitory effect than crude extract and rutin. It was also observed that polyphenolic extracts obtained from vitex, terebinth and mastic leaves showed high inhibition capacities, it was thought that fractionation should be performed for these plants. As a more general conclusion, it was revealed that harmal seed alkaloids and olive leaf fractions with high purity are promising natural COMT inhibitors. By performing this study, the kinetic inhibition constants of extracts, their fractions and standards could be determined and they could be reported into literature.Master Thesis The Production of Thymoquinone From Thymol and Carvacrol by Using Zeolite Catalysts(Izmir Institute of Technology, 2005) Güneş, Alev; Bayraktar, OğuzIn this thesis study, by using general flexible ligand method, Cr(III), Fe(III),Bi(III), Ni(II) and Zn(II) complexes of N,Nbis(salicylidene)propane-1,3-diamine (H2salpn) encapsulated in NaY-zeolite were prepared. All catalyst were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) analyses to confirm the complex encapsulation. Activities of all prepared catalysts for the decomposition of hydrogen peroxide and oxidation of carvacrol were tested. Leaching test or heterogeneity test was also performed. The performances of all catalysts were compared based on the leaching test results and carvacrol conversion. Thymohydroquinone and benzoquinones were observed as by-products at high conversions of carvacrol. No product was formed in the absence of a catalyst. Fe(salpn)-NaY catalyst has shown the highest carvacrol conversion of 27.6% with a yield of 22.0% which was followed by Cr(salpn)-NaY catalyst with 23.5% carvacrol conversion with a yield of 17.6%. Other catalysts have shown relatively lower performances in terms of carvacrol conversion and leaching. The Cr(salpn)-NaY catalyst was found to be a more efficient catalyst than others based on leaching and activity tests. Selected catalyst was extra characterized by Brunauer Emmett and Teller (BET) and Thermal gravimetric (TGA) analyses. With selected catalyst Cr (salpn)-NaY, temperature, catalyst amount, reactant carvacrol to hydrogen peroxide molar ratio effects were investigated in carvacrol oxidation reactions. Increasing the temperature from 40 to 60C caused the increment of thymoquinone yield from 6.2 to 16.0%. In addition to that the yield of thymoquinone was increased from 7.4 to 20.7% by increasing catalyst amount from 0.05 to 0.2 g. And also thymoquione yield was increased from 3.7 to 23.0% by decreasing carvacrol to hydrogen peroxide molar ratio from 1 to 3. Moreover, Cr (salpn)-Y catalyst was also tested in thymol and essential oil oxidation reactions.