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Öğe Antioxidant Potential of Different Dill (Anethum Graveolens L.) Leaf Extracts(Taylor & Francis Inc, 2011) Isbilir, Sebnem Selen; Sagiroglu, AytenDill (Anethum graveolens L.) have been extensively used in salads, soups, and pickles for its aromatic odor and flavor. Recently, interest in plant-derived food additives has grown. In this study, the possible antioxidant properties of water, ethanol, and acetone extracts of dill leaves were investigated. In order to evaluate antioxidant activities of all extracts, different antioxidant tests were used, such as total antioxidant activity by ferric thiocyanate method, reducing power, DPPH (1,1-diphenyl-2-picryl-hydrazyl) free radical scavenging, hydrogen peroxide scavenging, and ferrous ions chelating activities. The content of phenolic compounds was also determined to be the gallic acid equivalent. Among the three extracts, the water extract of dill leaf showed the most potent antioxidative capacity in each assay, showing 79.66% (at 1 mg/mL) in the DPPH center dot radical scavenging activity, 63% (at 800 g/mL) in the metal chelating effect, 60% (at 400 g/mL) in the H2O2 scavenging activity, and 0.61 absorbance (at 1 mg/mL) in the reducing power.Öğe AN ASSESSMENT OF IN VITRO ANTIOXIDANT ACTIVITIES OF DIFFERENT EXTRACTS FROM PAPAVER RHOEAS L. LEAVES(Taylor & Francis Inc, 2012) Isbilir, Sebnem Selen; Sagiroglu, AytenCorn poppy (Papaver rhoeas L.) leaf has been extensively used as garniture in salads and drugs in folk medicine. In this study, the possible antioxidant properties of water (WE), ethanol (EE), and acetone (AE) extracts of corn poppy leaves were investigated using different antioxidant tests, including total antioxidant activity in linoleic acid system, DPPH center dot scavenging activity, reducing power, chelation activity, and hydrogen peroxide scavenging activity. In addition, the amount of total phenolics was also determined. Total antioxidant activities of all extracts were greater than 85% at 400 mu g/mL concentration. The scavenging effects of WE and EE on DPPH center dot radical were found to be 88.46 +/- 0.08% and 86.81 +/- 0.37% at 800 mu g/mL concentration, respectively, which was comparable to standard antioxidants, such as BHA and alpha-TP. The reducing power of extracts was in the order of WE > EE > AE. The percentage of metal chelating activity of 800 mu g/mL concentration of WE was found to be 79.51 +/- 4.05%. Our results indicated that the leaves of Papaver rhoeas L. showed the potential to be used as a natural antioxidant.Öğe Assessment of in vitro Antioxidant and Antidiabetic Capacities of Medlar (Mespilus germanica)(Univ Agr Sci & Veterinary Med Cluj-Napoca, 2019) Isbilir, Sebnem Selen; Kabala, Sevilay Inal; Yagar, HulyaThe objective of the current study was to evaluate the antioxidant activity and enzyme inhibitory effect of different parts of medlar including fruit, leaf and flower bud by using various in vitro methods, and also determination of total phenolic and flavonoid content in the samples. Ethanol extracts of medlar parts were prepared and their antioxidant activities were determined using 1,1-diphenyl-2-picryl-hydrazil (DPPH center dot) scavenging and beta-carotene bleaching methods. The leaf extract showed the strongest antioxidant activity. DPPH radical scavenging activity was in the order of BHA > leaf > bud > fruit. This ordering was the same for beta-carotene bleaching activity, tocopherol > leaf > bud > fruit. The highest total phenolic (60.3 +/- 1.69 mg GAE g(-1) extract) and flavonoid (14.77 +/- 1.15 mg QE g(-1 )extract) content were determined in leaf extract. For possible antidiabetic effects of extracts, alpha-amylase and alpha-glucosidase inhibitory activities were investigated, the bud extract showed the highest inhibition activities among the all extracts.Öğe Comparison of antioxidant activities of juice, peel, and seed of pomegranate (Punica granatum L.) and inter-relationships with total phenolic, Tannin, anthocyanin, and flavonoid contents(Korean Society Food Science & Technology-Kosfost, 2012) Orak, Hakime Hulya; Yagar, Hulya; Isbilir, Sebnem SelenIn this study, the antioxidant activities of juice, peel, and seed parts of pomegranate were investigated by using DPPH scavenging activity, beta-carotene bleaching method, reducing power, and metal chelating activity. Sample of pomegranates which are named Punica granatum L. cv. Hicaznar, genotype 19-121, genotype 17-67, and genotype 19-66 obtained from BATEM (West Mediterranean Agricultural Research Institute) in Anlalya. The EC50 values of DPPH scavenging activities in peel extracts (PE) had 23.4-fold higher than the juice extracts (JE), and the seed extracts (SE) had 2.3-fold higher than JE. The reducing power in peel extracts was found to be 4.7-fold higher than SE and 10.5-fold higher than the JE. The highest metal chelating capacity (37.22%) was determined in peel, while the lowest (7.151%) in seed. Generally, in peel, the total polyphenol, flavonoid, tannin contents, and in juice, the total polyphenol, anthocyanin, tannin contents, and acidity significantly affected to antioxidant activities.Öğe COMPARISON OF BIODIESEL PRODUCTIVITIES OF DIFFERENT VEGETABLE OILS BY ACIDIC CATALYSIS(Assoc Chemical Eng, 2011) Sagiroglu, Ayten; Isbilir, Sebnem Selen; Ozcan, Hakki Mevlut; Paluzar, Hatice; Toprakkiran, Neslihan M.Biodiesel has become a subject which increasingly attracts worldwide attention because of its environmental benefits, biodegradability and renewability. Biodiesel production typically involves the transesterification of a triglyceride feedstock with methanol or other short-chain alcohols. This paper presents a study of transesterification of various vegetable oils, sunflower, safflower, canola, soybean, olive, corn, hazelnut and waste sunflower oils, with the acidic catalyst. Under laboratory conditions, fatty acid methyl esters (FAME) were prepared by using methanol in the presence of 1.85% hydrochloric acid at 100 degrees C for 1 h and 25 degrees C for 3 h. The analyses of biodiesel were carried out by gas chromatography and thin layer chromatography. Also, biodiesel productivities (%) were determined on basis of the ratio of ester to oil content (w/w). The biodiesel productivities for all oils were found to be about 80% and about 90% at 25 and 100 degrees C, respectively. Also, the results showed that the yield of biodiesel depended on temperature for some oils, including canola, sunflower, safflower Os, but it was not found significant differences among all of the oil types on biodiesel productivities.Öğe DETERMINATION OF ANTIOXIDANT ACTIVITIES OF STRAWBERRY TREE (Arbutus unedo L.) FLOWERS AND FRUITS AT DIFFERENT RIPENING STAGES(Wydawnictwo Akad Rolniczej W Lublinie, 2012) Isbilir, Sebnem Selen; Orak, Hakime Hulya; Yagar, Hulya; Ekinci, NeslihanIn this study, the antioxidant activities of Strawberry tree (Arbutus unedo L.) flowers at flowering period and fruits during ripening period were investigated, along with some ripening characteristics such as color, reducing sugar and acidity. Antioxidant activity characteristics were investigated using by the methods of DPPH (1,1-Diphenyl-2-picryl-hydrazyl) scavenging activity, beta-carotene bleaching, reducing power, metal chelating capacity, superoxide anion scavenging and hydrogen peroxide scavenging activity in water, ethanol and methanol extracts. The total phenolic content of flowers in water extracts was found to be 232.38 +/- 7.19 mg GAE . g(-1) extract, and the DPPH activity was 81.3 +/- 0.49% at 50 mu g.ml(-1) concentration. In the ripening stages, the fully red fruits were determined higher antioxidant capacity than green and yellow fruits, except H2O2 scavenging activity which was highest in green fruit. In correlation study, the highest relationship was found between total phenolic content with reducing power (r(2) = 0.987**, P < 0.01), while the lowest with H2O2 scavenging activity (r(2) = 0.519*, P < 0.05).Öğe Determination of antioxidant properties of lyophilized olive leaf water extracts obtained from 21 different cultivars(Korean Society Food Science & Technology-Kosfost, 2012) Orak, Hakime Hulya; Isbilir, Sebnem Selen; Yagar, HulyaThe objective of this study was to compare the antioxidant activities of lyophilized olive leaf water extracts (OLWExtracts) from 21 different olive tree cultivars. The highest total phenolic content (102.69 +/- 1.63 mu g GAE/mg extract) was found in cultivar 'Esek Zeytini' and the lowest content (78.52 +/- 2.18 mu g GAE/mg extract) was in 'Uslu'. The highest total flavonoid content (12.47 +/- 0.12 mu g QE/mg extract) obtained from 'Frantoio'. According to EC50 values, 'Domat' have the highest DPPH scavenging activity (EC50 =59 mu g/mL), reducing power (EC50 =180 mu g/mL), and superoxide radical scavenging capacity (EC50=44 mu g/mL). While, 'Ascolana' showed the highest metal chelating capacity (EC50=163 mu g/mL), 'Memecik' showed the highest hydrogen peroxide (H2O2) scavenging capacity. Research results exhibited that OLWExtracts are comparable to synthetic antioxidants. The correlation study showed that while total phenolic content correlated with DPPH scavenging activity and reducing power (p < 0.01), total flavonoid content correlated with metal chelating and superoxide radical scavenging capacity (p < 0.05).Öğe Effects of natural waste on in vitro oxidative DNA damage(Taylor & Francis Ltd, 2024) Danjolli-Hashani, Dua; Isbilir, Sebnem SelenIn this study, the effects of natural waste products such as extracts from C. coggygria leaves and Punica granatum L. peels were investigated against oxidative DNA damage induced by Fenton reaction. 8-OH-2'dG as a general marker of DNA damage on thymus DNA, and the bioactive compounds of extracts were measured by LC-MS/MS. Our results had shown that ethanol extracts of C. coggygria leaf and Punica granatum L. peel had a protective effect on oxidative damaged DNA. It was determined that the bioactive compounds of C. coggygria leaves (gallic acid, protocatechuic acid, myricetin, syringic acid and ethyl gallate as a major compounds) and Punica granatum L. peel (ellagic acid, abscisic acid, ethyl gallate, phlorizin, gallic acid, myricetin as major compounds) may have an important role in the protective effect against oxidative DNA damage. Therefore, Cotinus coggygria leaves and Punica granatum L. peel may have potential use in medicine or cosmetic fields.Öğe Evaluation of Antioxidant and Antimicrobial Potential of Strawberry Tree (Arbutus Unedo L.) Leaf(Korean Society Food Science & Technology-Kosfost, 2011) Orak, Hakime Hulya; Yagar, Hulya; Isbilir, Sebnem Selen; Demirci, Ahmet Sukru; Gumus, Tuncay; Ekinci, NeslihanIn present study, antioxidant and antimicrobial activities of strawberry tree (Arbutus unedo L.) leaves were investigated. Antioxidant activity was determined by methods of DPPH scavenging, beta-carotene bleaching, reducing power, metal chelating, superoxide anion scavenging, and hydrogen peroxide scavenging activity. Total phenolic content were determined to be 197.16 +/- 1.43 mg GAE/g extract in aqueous extract. The EC50 value of methanolic extracts was found to be 0.423 mg/mL. The extracts of leaves showed nearly 1/4 metal chelating capacity of standard EDTA, high reducing power, superoxide anion scavenging, and hydrogen peroxide scavenging activities. While the strawberry tree leaves exhibited antibacterial activity against Staphylococcus aureus, there was no inhibitory effect against Escherichia coli and Salmonella enteritidis. The strawberry tree leaves exhibited antifungal effect against 2 aflatoxigenic molds namely Aspergillus parasiticus NRRL 2999 and NRRL 465. These results suggest that the strawberry tree leaves may be used as an antioxidant source for pharmaceutical application, nutraceutical and functional food industries.Öğe Some biochemical properties of lipase from bay laurel (Laurus nobilis L.) seeds(Wiley, 2008) Isbilir, Sebnem Selen; Ozcan, Hakki M.; Yagar, HulyaLipase was isolated from bay laurel (Laurus nobilis L.) seeds, some biochemical properties were determined. The bay laurel oil was used as the substrate in all experiments. The pH optimum was found to be 8.0 in the presence of this substrate. The temperature optimum was 50 degrees C. The specific activity of the lipase was found to be 296 U mg protein(-1) in optimal conditions. The enzyme activity is quite stable in the range of pH 7.0-10. The enzyme was stable for 1 h at its optimum temperature, and retained about 68% of activity at 60 degrees C during this time. K-m and V-max values were determined as 0.975 g and 1.298 U mg protein(-1), respectively. Also, storage stability and metal effect on lipolytic activity were investigated. Enzyme activity was maintained for 9, 12, and 42 days at room temperature, 4 and -20 degrees C, respectively. Ca2+, Co2+, Cu2+, Fe2+, and Mg2+ lightly enhanced bay laurel lipase activity.Öğe Total phenolic content, antiradical and antioxidant activities of wild and cultivated Rumex acetosella L. extracts(Taylor & Francis Ltd, 2013) Isbilir, Sebnem Selen; Sagiroglu, AytenEdible greens, especially wild greens, play an important role in traditional diets and are rich in phenols and other compounds. The purpose of this study was to investigate total phenolic content (TPC) and antioxidant activities of ethanolic extracts from wild and cultivated Rumex acetosella L. The wild sheep sorrel extract inhibited lipid peroxidation and 1,1-diphenyl-2-picrylhydrazyl radical with EC50 values of 0.02 and 3.67mgml(-1); however, the EC50 values for cultivated sheep sorrel extract were 0.76 and 21.94mg ml(-1). In the reducing power assay, the values of measured absorbance were 0.723 and 0.430 for wild and cultivated extracts, respectively, at 1mgml(-1) concentration. The chelating of ferrous ions by the wild and cultivated sheep sorrel was determined as 59.4% and 56.2%, respectively, at 1mgml(-1) concentration. TPC of wild and cultivated sheep sorrel was found to be 69.21 +/- 8.5 and 57.57 +/- 1.8mg gallic acid equiv. g(-1) extract, respectively. There is a positive correlation between phenolic content and antioxidant assays. The results obtained in this study indicate that wild R. acetosella could be an important dietary source because of its good antioxidant properties.
