Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2018A rapid and sensitive spectrofluorometric method for the determination of au(III) based on fluorescence quenching of a 1,3,5-triphenyl-2-pyrazoline
Başoğlu, Aysel; Ocak, Ümmühan; Fandakli, Seda; Yayli, Nurettin
A simple, rapid, sensitive, and low-cost spectrofluorometric method was developed for the determination of Au(III) using 5-(2,3-dimethoxyphenyl)-3-(4-methoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (L) in ethanol/water. The method is based on the change in the fluorescence intensity at 464 nm after excitation at 355 nm as a result of the reaction between the ligand and Au(III). The fluorescent emission of ligand at 464 nm decreased with the increasing of Au(III) concentration. The ligand concentration, pH effect, response time, and effect of foreign ions were determined. From the results of fluorescence titration experiments, it was found that the ligand (1 × 10−7 M) was selective and sensitive to Au(III) in EtOH-H2 O (1:1, v/v, phthalate buffer, pH 4.0). The calibration curve showed good linearity in the concentration range of 17.4–237.6 µg L−1 Au(III). The limits of detection and quantification were 5.2 and 17.4 µg L−1 Au(III) with a response time of 1 min, respectively. Satisfactory accuracy was obtained for standard reference material (CRM-SA-C Sandy Soil C). The proposed method was successfully applied to the determination of Au(III) in tap water, sea water, and stream water samples, and high levels of recovery were obtained.
- MakaleAçık Erişim2018Antioxidant activity, sugar content and phenolic profiling of blueberries cultivars: A comprehensive comparison
Okan, Onur Tolga; Deniz, Ilhan; Yayli, Nurettin; Şat, Ihsan Güngör; öz, Mehmet; Serdar, Gönül Hatipoğlu
Commercial blueberry production has been a viable industry throughout the world for 95 years; because of blueberry is a good source of antioxidant. Blueberries are especially rich in anthocyanin, a flavonoid with potent antioxidant capacity. The aim of this study was to compare the phenolic quantities, antioxidant activities, anthocyanin, sugar and phenolic compounds of blueberries produced in Turkey with those of similar blueberry varieties produced around the world. As a result of the conducted analysis, the total phenolic content (TPC) amount found in the berries was 77.26-215.12 mg GAE/100 g, the total flavonoid content (TFC) was 30.44-91.69 mg QE/100 g and the total anthocyanin content (TAC) was 43.03-295.06 mg c3- GE/100 g. Examining the antioxidant activities of the berries, DPPH between 1.10-5.65 mg/ml, FRAP between 454.93- 36832.96 μmol troloks/100 g, β-Carotene between 40.66-86.48%. It was determined that the natural berries contained much more phenolic compounds and higher antioxidant activity than that of the cultivars The result of HPLC analysis, chlorogenic acid is determined to be the dominant compound in all berries. Furthermore, fructose and glucose are found in all fruits in different quantities while sucrose is found in certain varieties of berries as well. At the end of the performed study the data indicate that wild and cultivars of blueberries are rich sources of antioxidants for local as well international industries importing this fruit for food processing and enormous products.
- MakaleAçık Erişim2015Synthesis and biological evaluation of a new series of 4-alkoxy-2-arylquinoline derivatives as potential antituberculosis agents
Tosun, Gonca; Arslan, Tayfun; Iskefiyeli, Zeynep; Küçük, Murat; Karaoʇlu, Şengül Alpay; Yayli, Nurettin
Three new series of 33 quinolone compounds, 2-(2-, 3-, and 4-fluorophenyl)-4-O-alkyl(C5-15)quinolines (7a-k, 8a-k, and 9a-k), were synthesized from 2-(2-, 3-, and 4-fluorophenyl)-2,3-dihydroquinolin-4(1H )-one (4, 5, and 6) by the reaction of alkyl halides under basic conditions in DMF. The new compounds 7a-k, 8a-k, and 9a-k were synthesized from flavonones 4-6, which can be considered new precursors for quinoline synthesis through a one-step reaction. All the target compounds (7a-k, 8a-k, and 9a-k) were evaluated for their in vitro antimicrobial activity against nine test microorganisms. They showed the most activity against Mycobacterium smegmatis with minimum inhibitory concentrations (MIC) of 62.5-500 μg/mL, indicating their potential uses as antituberculosis agents. Among them 8a-k (m-fluoride) were the most active compounds against M. smegmatis (MIC, 62.5-125 μg/mL). The newly synthesized title compounds were also evaluated for their in vitro antioxidant activities using DPPH• radical scavenging and FRAP tests. They showed at a low concentration (mg/mL) a range of SC50 values of 0.03-12.48 mg/mL (DPPH•) and 0-722 μM (FRAP), respectively. The antioxidant results of compounds 7a-k, 8a-k, and 9a-k revealed that the length of the alkyl chain was negatively correlated with antioxidant capacity.
- MakaleYalnız künye2011A proficiency test scheme for the quality control of black tea and development of quality control material for internal quality control
Baltaci, Cemalettin; Ilyasoǧlu, Huri; Sarikaya, Sevim Beyza Öztürk; Cavrar, Sevda; Yayli, Nurettin
A proficiency test (PT) was organized for quality control analysis of black tea. Test materials for the analyses of total content of powder tea, moisture, total ash, acid-insoluble ash, water-soluble ash, alkalinity of water-soluble ash, water extract, crude fiber and caffeine were sent to the participant laboratories (n:43) in 2009. The assigned value, standard deviation of the parameters and z-scores of the participant laboratories were calculated using the data reported by the participants. The percentage of the reported results for analytes was found to be ranged from 67.5 to 100%. Acceptable z-scores were achieved by 80.5-97.5% of the participant laboratories. More than 15% of unacceptable results were obtained for acid-insoluble ash and caffeine analyses. The quality control material for quality control analysis of black tea was developed from the remaining material.
- MakaleYalnız künye2011Microwave assisted essential oil analysis and antimicrobial activity of M. alpestris subsp. alpestris
Cansu, Tayyibe Beyza; Yücel, Murat; Sinek, Kadriye; Baltaci, Cemalettin; Karaoglu, Sengül Alpay; Yayli, Nurettin
The present work describes the chemical composition and antimicrobial activity of the essential oil of Myosotis alpestris F.W. Schmidt subsp. alpestris (Boraginaceae). The essential oil was obtained from all parts of the plant by microwave distillation and analyzed by GCFID and GC-MS. Forty-seven components representing 88.2 % of the total oil were characterized and the main components of this species were found to be n-nonanal (11.8 %), decanal (10.8 %), n-octanal (10.7 %), hexahydrofanesyl acetone (6.6 %), o-cymene (3.9 %), tetradecanal (3.7 %), eicosanol (2.2 %) and E-β-farnesene (2.0 %). The isolated essential oils of M. alpestris subsp. alpestris was tested for antimicrobial activity against the bacteria Escherichia coli, Yersinia pseudotuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Mycobacterium smegmatis and the fungus Candida albicans and Saccharomyces cerevisiae at maximum essential oil concentration in hexane of 1000 μg/mL and they showed only antibacterial activity against fungus bacteria.