Bioengineering / Biyomühendislik

Permanent URI for this collectionhttps://hdl.handle.net/11147/4529

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COAR Access Rights: search.filters.coarAccessRights.open accessInstitution Author: search.filters.institutionAuthor.Erdoğan, İpek

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Now showing 1 - 6 of 6
  • Conference Object
    In Vitro Antitumor Activity of Sarcopoterium Spinosum Leaf Extract With Bioactive Natural Compounds
    (Elsevier, 2013) Süngüç, Ceren; Erdoğan, İpek; Uslu, Mehmet Emin; Bayraktar, Oğuz
    Cancer cell lines cause generation of reactive oxygen species and free radicals at high levels (Wang and Yi, 2008). Then generated free radicals lead to breakdown of the structure of DNA, lipid or protein (Gul et al., 2011). When plant extracts including antioxidant phytochemicals are exposed to the redox reactions, the harmful effects of free radicals are effectively prevented. The aim of present research was to evaluate the antitumor potential of the extract derived from Sarcopoterium spinosum leaves. The leaves of S. spinosum were collected in Izmir, Turkey. Total phenol content of ethanolic.
  • Conference Object
    Investigation of Anti-Tumoral Activity of Cistus Creticus Extract Against Pc-3 Cell Line
    (Elsevier, 2013) Erdoğan, İpek; Süngüç, Ceren; Uslu, Mehmet Emin; Bayraktar, Oğuz
    Recent studies have revealed that plant extracts show cytotoxic activities against cancer cell lines by ceasing cell division in particular phases (Xu et al., 2012, Yıldırım et al., 2013). Expression of specific genes was found to be activated according to pathway in which cell death occurs. Objective of this study was to identify antitumoural effect of Cistus creticus, which is a perennial shrub, found in Mediterranean region, against prostate cancer cell line by measuring the cytotoxic activities and apoptotic gene expression levels.
  • Article
    Citation - WoS: 8
    Wound Healing Effects of Various Fractions of Olive Leaf Extract (ole) on Mouse Fibroblasts
    (Ars Docendi, 2018) Erdoğan, İpek; Bayraktar, Oğuz; Uslu, Mehmet Emin; Tüncel, Özge
    Olive (Olea europaea) leaf has been introduced as a potential therapeutic in wound healing owing to combined antioxidant and antimicrobial activity. Comparison of crude extract and its fractions in terms of antioxidant capacity, antimicrobial and cytotoxic activity to gain insight about cell migration rate under exogenous stress of H2O2, as a hallmark of wound healing constituted the objective of this study. Oleuropein-containing fraction exerted the highest cell migration rate among other fractions that contains hydroxytyrosol, verbascoside and luteolin, whilst treatment with high concentrations (50 mu g/ml) of this fraction simultaneously with H2O2 caused a dramatic decline in cell migration, resulting in the loss of cell adherence. Results overall indicated that active compounds caused an imbalance in redox signaling beyond a critical concentration. Comparison of fractions and crude extract also revealed that crude extract promoted cell migration by 20%, which may be attributed to synergistic effect of undefined phenolics.
  • Article
    Citation - WoS: 30
    Citation - Scopus: 35
    Bioactive Sheath/Core Nanofibers Containing Olive Leaf Extract
    (John Wiley and Sons Inc., 2016) Doğan, Gamze; Başal, Güldemet; Bayraktar, Oğuz; Özyıldız, Figen; Uzel, Ataç; Erdoğan, İpek
    This study aimed at producing silk fibroin (SF)/hyaluronic acid (HA) and olive leaf extract (OLE) nanofibers with sheath/core morphology by coaxial electrospinning method, determining their antimicrobial properties, and examining release profiles of OLE from these coaxial nanofibers. Optimum electrospinning process and solution parameters were determined to obtain uniform and bead-free coaxial nanofibers. Scanning electron microscopy and transmission electron microscopy (TEM) were used to characterize the morphology of the nanofibers. The antimicrobial activities of nanofibers were tested according to AATCC test method 100. Total phenolic content and total antioxidant activity were tested using in vitro batch release system. The quality and quantity of released components of OLE were determined by high-performance liquid chromatography. The changes in nanofibers were examined by Fourier-transform infrared spectroscopy. Uniform and bead-free nanofibers were produced successfully. TEM images confirmed the coaxial structure. OLE-loaded nanofibers demonstrated almost perfect antibacterial activities against both of gram-negative and gram-positive bacteria. Antifungal activity against C. albicans was rather poor. After a release period of 1 month, it was observed that ∼70-95% of the OLE was released from nanofibers and it was still bioactive. Overall results indicate that the resultant shell/core nanofibers have a great potential to be used as biomaterials.
  • Article
    Citation - WoS: 35
    Citation - Scopus: 40
    Olive Leaf Extract as a Crosslinking Agent for the Preparation of Electrospun Zein Fibers
    (John Wiley and Sons Inc., 2015) Erdogan, I.; Demir, M.; Bayraktar, O.
    Incorporating active agents, reinforcing structure by crosslinking, thus changing release properties, can be listed as possible modifications in preparation methods of biopolymer fibers. This study introduces oleuropein, major component of olive leaf extract (OLE), as a natural functional crosslinker for electrospun zein fibers, owing to its antioxidant and antimicrobial properties. Incorporation of OLE causes morphological and structural changes indicated by a decrease in fiber diameter up to 27%, an increase in intensity of NH bending region due to interaction with -OH groups and observation of characteristic oleuropein bands. Extract addition also enhances thermal stability. Zein fibers without OLE is fully degraded at 600C, whereas 10% of OLE loaded zein fibers is left undegraded. Fifty percent of initial phenolic content loaded into fibers is released which indicate the effect of OLE incorporation as accumulation of oleuropein. OLE-incorporated fibers immersed in PBS are less fused than pure zein fibers, due to the crosslinking effect. © 2014 Wiley Periodicals, Inc.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 24
    Optimization of Extraction Conditions for Active Components in Equisetum Arvense Extract
    (Ars Docendi, 2013) Uslu, Mehmet Emin; Erdoğan, İpek; Bayraktar, Oğuz; Ateş, Mehmet
    Response surface methodology was applied to predict optimum conditions for equisetum arvense extraction. Central composite design was used to monitor the effects of temperature, stirring speed, ethanol percent, extraction time, solid-liquid ratio on dependent variables such as, extract yield percent, total phenol content, total antioxidant capacity, silicic acid amount. According to the mathematical models obtained from the analysis, the highest values for yield percent, total phenol content, total antioxidant capacity and silicic acid amount were found to be 18.67 %, 123 mg gallic acid gr-1 dry weight extract, 1608 μM TEAC mg-1 dry weight extract and 0.0049 mg silicic acid mg-1 dry weight extract, respectively. The plant extracts were analyzed with HPLC to determine the phenolic content and compositional differences of extracts obtained at different extraction conditions. Plant extracts were also analyzed for their cytotoxic and antimicrobial activities. The high total antioxidant capacity and total phenolic content resulted in an increased cytotoxic effect on fibroblast cells. Equisetum arvense extracts showed antimicrobial activity against Staphylococcus epidermidis and Escherichia coli bacteria, however showed no effect against Candida albicans. © 2013 University of Bucharest.