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    ANTIBACTERIAL ACTIVITIES OF EXTRACTS FROM TWELVE CENTAUREA SPECIES FROM TURKEY
    (Inst Bioloska Istrazivanja Sinisa Stankovic, 2011) Tekeli, Yener; Zengin, Gokhan; Aktumsek, Abdurrahman; Sezgin, Mehmet; Torlak, Emrah
    Members of the genus Centaurea (Asteraceae) have been used in traditional plant-based medicine. The methanol extracts of twelve Centaurea species, of which five are endemic to Turkey flora, were screened for antibacterial activity against four bacteria (Escherichia coli, Bacillus cereus, Salmonella enteritidis, Staphylococcus aureus). The antibacterial activity was evaluated by the microdilution method and the minimum inhibition concentrations (MIC) of the extracts were determined. C. cariensis subsp. microlepis exhibited an antimicrobial effect on all tested microorganisms. The extracts from eight Centaurea species (C. balsamita, C. calolepis, C. cariensis subsp. maculiceps, C. cariensis subsp. microlepis, C. kotschyi var. kotschyi, C. solstitialis subsp. solstitialis, C. urvillei subsp. urvillei and C. virgata) possessed antibacterial activity against several of the tested microorganisms.
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    Antioxidant Activities and Phenolic Compounds of Two Endemic Taxa of Labiatae Sideritis
    (Chiminform Data S A, 2012) Tekeli, Yener
    Sideritis species have very high antioxidant activity and and are used in a range of treatments by alternative medicine. This study examined the antioxidant activities and phenolic compositions of endemic 2 Sideritis species (Sideritis phrygia Bornm and ideritis bilgerana P.H. Davis), which were collected in the Konya region of Turkey. The oil content was extracted with petroleum ether using a soxhlet extractor. The defatted plant materials were extracted with methanol and then filtered and concentrated in vacuo at 45 degrees C. Finally, the extracts were lyophilized and stored in the dark at +4 degrees C until analyzed for antioxidant activity. Total phenol concentration of the extracts were estimated with Folin-Ciocalteu reagent using gallic acid as standard, free radical scavenging activities were determined based on DPPH(2,2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) was determined based on the method proposed by Oyaizu. Results were compared with standard BHT(Butylated hydroxytoluene) and BHA (Butylated hydroxyanisole The phenolic composition of the samples was determined using HPLC. The results indicated that S. phrygia and S. bilgerana showed significant antioxidant effect and 6 phenolic compounds used in standard phenolic compounds. S. phrygia showed higher antioxidant capacity than S. bilgerana.
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    ANTIOXIDANT ACTIVITIES OF BLACK CUMIN (NIGELLA SATIVA L.) SEEDS CULTIVATING IN DIFFERENT REGIONS OF TURKEY
    (Wiley, 2010) Sen, Nejdet; Kar, Yakup; Tekeli, Yener
    In this study, the antioxidant activity of the methanolic extracts of the black cumin (Nigella sativa L.) seeds collected from Konya, Isparta, Corum, Burdur, Afyon and Samsun was evaluated using three different methods, specifically the beta-carotene and linoleic acid system, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and reducing power assays. Among the six black cumin samples of different origins, the black cumin sample origins from Konya city showed the most potent radical scavenging activity in each assay, showing 94.59% (at 1 mg/mL) in the beta-carotene bleaching method and 44.44% in the DPPH radical scavenging method (at 0.5 mg/mL). Positive correlations were found between the total phenolic content in the black cumin extracts and their antioxidant activities. The values of their antioxidant activity were either equivalent to or higher than those of positive BHA and BHT controls. These satisfying results lead to expect the use of black cumin seeds as health-promoting ingredients such as dietary supplements and nutraceuticals.
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    Biodiesel production from canola oil using immobilized lipase
    (Sila Science, 2011) Yucel, Yasin; Tekeli, Yener
    In the present work, lipase (triacylglycerol hydrolase, EC 3.1.1.3) Novozyme 388 was immobilized onto celite 545 using both adsorption and covalent method. The maximum immobilization yield was obtained as 78.50% when lipase immobilized by covalent method and the highest specific activity was 5.81 U/mg protein for adsorption method. The properties of the support and immobilized derivative were evaluated by fourier transform infrared spectroscopy (FTIR). Immobilized enzyme was used for biodiesel production by transesterification of crude canola oil and methanol. Maximum methyl esters yield was obtained as 98%. Celite 545 activated with polygluturaldehyde proved to be stable after even 10 reuses with each batch of 6 h and lost little activity when was subjected to repeated use. However, the immobilized lipase without polyglutaraldehyde on support material was lost its whole activity after five repeated reuses.
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    THE EFFECTS OF SEASONS ON CHOLESTEROL CONTENT AND FATTY ACID COMPOSITIONS OF MUSCLE OF HELIX ASPERSA LIVING IN KONYA, TURKEY
    (African Networks Ethnomedicines, 2014) Citil, Ozcan Baris; Tekeli, Yener; Danahaliloglu, Hatice; Bucak, Serbay
    Background: The aim of the present study is the determination of the effects of seasonal variations on the proximate analysis, cholesterol content and fatty acid compositions of Helix aspersa. Materials and Methods: Garden snails (Helix aspersa) were picked up by hand from the Central Anatolia Region of Turkey, in autumn (November) and spring (April) in 2011. Fatty acid methyl esters (FAMEs) and cholesterol analysis were analyzed by gas chromatography (GC). The protein contents of snail muscle were determined with Kjeldahl distillation units. Statistical comparisons were made by using SPSS Software (version 16.0). Results: Thirty different fatty acids of different saturation levels were detected. As the predominant fatty acids, stearic acid (C18:0), oleic acid (C18:1 omega 9), linoleic acid (C18:2 omega 6), palmitic acid (C16:0), arachidonic acid (C20:4 omega 6), eicosadienoic acid (C20:2) and linolenic acid (C18:3 omega 3) were found in Helix aspersa. Palmitic acid (C16:0) was identified as the major SFA in autumn and spring. Linoleic acid (C18:2 omega 6), eicosadienoic acid (C20:2) and arachidonic acid (C20:4 omega 6) have the highest levels among the PUFAs. In the present study, omega 3 were found 5.48% and 13.94% in autumn and spring, respectively. Conclusion: Linolenic acid and omega-3 fatty acid amounts in the spring increased significantly but cholesterol content was not affected in Helix aspersa both in season.
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    Fatty acid composition of six Centaurea species growing in Konya, Turkey
    (Taylor & Francis Ltd, 2010) Tekeli, Yener; Sezgin, Mehmet; Aktumsek, Abdurrahman; Guler, Gokalp Ozmen; Sanda, Murad Aydin
    In this study, fatty acid compositions of six Centaurea species growing in the Konya region were determined. The fatty acid composition of Centaurea balsamita, Centaurea calolepis, Centaurea carduiformis subsp. carduiformis, Centaurea cariensis subsp. maculiceps, C. cariensis subsp. microlepis and Centaurea iberica were analysed. Four species of these six Centaurea are endemic to Turkey. The endemic Centaurea species are C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps and C. cariensis subsp. microlepis. Generally, C 18:2 6 linoleic acid, C 16:0 palmitic acid, C 18:3 3 linolenic acid and C 18:1 oleic acid were found to be the major fatty acids in all species. Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids and monounsaturated fatty acids in all species. PUFAs were determined at 55.10%, 50.25%, 51.41%, 41.02%, 46.18% and 58.80% in C. balsamita, C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps, C. cariensis subsp. microlepis and C. iberica, respectively.
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    Hatay’da yetişen Verbascum tripolitanum’un bazı kimyasal ve biyolojik özellikleri
    (ABADER (Adıyaman Bilimsel Araştırmalar Derneği), 2019) Danahaliloğlu, Hatice; Tekeli, Yener; Güzel, Yelda
    u çalışmada, Hatay bölgesinde yetişen Verbascum tripolitanum’un antioksidan ve antimikrobiyal özellikleri, yağ asitleri içeriği belirlenmiştir. Toplam fenolik madde miktarı Folin-Ciocaltaeu yöntemi ile tayin edilmiştir. Antioksidan aktivite DPPH serbest radikal süpürme yöntemi, Fe+3 indirgeme metodu (FRAP), bakır iyonu indirgeme metodu (CUPRAC), ve β-karotenlinoleik asit emülsiyon yöntemleri ile test edilmiştir. V. tripolitanum’un antimikrobiyal etkisi 2 gram pozitif bakteri (Staphylococcus aureus, metisiline dirençli S. aureus), 2 gram negatif bakteri (Pseudomonas aeruginosa, Escherichia coli) ve 1 maya türüne (Candida albicans) karşı mikrodilüsyon broth metodu ile analiz edilmiştir. Yağ asitleri analizi için GC-FID kullanılmıştır.
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    PHENOLIC COMPOSITION, ANTIOXIDANT CAPACITY OF SALVIA VERTICCILATA AND EFFECT ON MULTIDRUG RESISTANT BACTERIA BY FLOW-CYTOMETRY
    (African Networks Ethnomedicines, 2014) Tekeli, Yener; Karpuz, Esra; Danahaliloglu, Hatice; Bucak, Serbay; Guzel, Yelda; Erdmann, Helmuth
    Background: Antioxidants are of great importance for preventing oxidative stress that may cause several degenerative diseases. Studies have indicated phytochemicals have high free-radical scavenging activity, which helps to reduce the risk of chronic diseases. The aim of the present study is the determination of antioxidant properties, polyphenolic content and multidrug resistant bacteria of Salvia verticcilata L. Materials and Methods: Methanol was used as the extraction solvent. The total phenolic content was calculated using Folin-Ciocalteau method and phenolic composition was determined by HPLC. The radical scavenging activity of plant was evaluated in vitro based on the reduction of the stable DPPH free radical. The reducing capacity was identified by using the FRAP method. The ability of Salvia verticcilata L. to increase the permeability of multidrug resistant bacterial cells was conducted by flow cytometric assay on Listeria innocua and E-coli. Results: The amount of total phenolics was found to be 347.5 mg GA/g extract. The IC50 value and FRAP assay are 0.61, and 0.944 respectively, Free radical scavenging effect and FRAP values are less than synthetic antioxidant compounds (BHA and BHT). Eight phenolic compounds were found in Salvia verticcilata L. Intense concentration of S. verticcilata L. has destroyed 97 % of living cells for Listeria innocua and 94.86% for E-coli Conclusion: This studyshows that methanolic extracts of Salvia verticcilata L. is a potential source of natural antioxidants and antimicrobial agent and can form the basis for pharmacological studies.