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Öğe Antioxidant Activity of Rumex conglomeratus P. Collected from Turkey(Asian Journal Of Chemistry, 2013) Kilic, Ismail; Yesiloglu, Yesim; Bayrak, Yuksel; Gulen, Sezer; Bakkal, TahirPlants contain a wide variety of free radical scavenging molecules, such as flavonoids, anthocyanins, carotenoids, dietary glutathionine, vitamins and endogenous metabolites and such natural products are rich in antioxidant activities. Rumex conglomeratus P. is widely spread in Turkey and used as an anticonstipate in traditional medicine. In this study, the antioxidant activity of water extract of R. conglomeratus was evaluated using different antioxidant tests. In addition, carotenoid content and proline level of R. conglomeratus were also determined. The results were compared with natural and synthetic antioxidants. The results showed that R. conglomeratus contained naturally occuring antioxidant components and possessed antioxidant activity which may be attributed to its radical scavenging and metal chelating activities. It was concluded that R. conglomeratus might be a potential source of antioxidants.Öğe Antioxidant properties of various solvent extracts from purple basil(Pergamon-Elsevier Science Ltd, 2012) Yesiloglu, Yesim; Sit, LatifsahWater, ethanol and acetone extracts from leaves and flowers of purple basil, one of the most popular spices consumed in the Thrace region of Turkey, were tested in vitro for their ability to inhibit peroxidation of lipids, to scavenge DPPH, hydrogen peroxide, superoxide anion, to reduce Fe(III) to Fe(II) and to chelate Fe(II) ions. The results showed that purple basil contained naturally occurring antioxidant components and possessed antioxidant activity which may be attributed to its lipid peroxidation inhibitory, radical scavenging and metal chelating activities. It was concluded that purple basil might be a potential source of antioxidants. (C) 2012 Elsevier B.V. All rights reserved.Öğe Biocatalytic Properties of Lipase from Walnut Seed (Juglans regia L.)(Wiley, 2010) Yesiloglu, Yesim; Demirkan, BoraLipase (E.C. 3.1.1.3) from walnut seed was purified 28.6-fold with 31% yield using Sephadex G-100 gel chromatography. Olive oil served as good substrate for the enzyme. The optimum pH and temperature were 9.0 and 70 A degrees C, respectively. The lipase was stable between 30 and 80 A degrees C for 5 min. K (m) and V (max) values were determined as 48 mM and 23.06 x 10(-3) U/min mg for triolein as substrate. Lipase activity was slightly reduced by Cu2+, Ca2+, Hg2+, Mn2+, and Ni2+ ions, while Mg2+ and Zn2+ had no effects. Anionic surfactant sodium dodecyl sulfate stimulated lipase activity while non-ionic surfactants Tween-80 and Triton X-100 had negligible effects on enzymatic activity. The enzyme activity was not affected by 50 mM urea and thioacetamide. Potassium ferricyanide, n-bromosuccinamide and potassium cyanide reduced the enzyme activity. The enzyme showed a good stability in organic solvents, the best result being in n-hexane (113% residual activity). The activity of dialysate was maintained approximately 80% for 1 year at -20 A degrees C.Öğe Biochemical Properties of Free and Immobilized Candida rugosa Lipase onto AL2O3: A Comparative Study(Informa Healthcare, 2011) Yesiloglu, Yesim; Sit, LatifsahLipase from Candida rugosa (CRL) was immobilized by physical adsorption onto Al2O3. The immobilization yield was more than 95% during 30 min. The properties of free and immobilized enzyme were also searched and compared. The optimum pH was shifted from 7 to 8.5 by immobilization of the enzyme. The maximum activity of the free and the immobilized enzymes occured at 35 and 40 degrees C, respectively.Öğe Evaluation of Antioxidant Activities of Turmeric Extracts from Turkey(Asian Journal Of Chemistry, 2013) Yesiloglu, Yesim; Aydin, HaticeThe aim of this study was to assess the in vitro potential of ethanolic and methanolic extracts of turmeric as a natural antioxidant. The iron chelation activity of the extracts was increased in a dose-dependent manner. The methanolic extract was found to be richer in antioxidant phytochemicals, such as phenolics (502.6 +/- 11.3 mg GAE/g DW) and flavonoids (303.2 +/- 4.1 mg PE/g DW). The total antioxidant activity was found to vary in the order: ethanolic extract > methanolic extract > ascorbic acid > alpha-tocopherol > BHT > BHA. Moreover, extracts had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and ABTS scavenging activity. The results obtained in this study clearly indicate that turmeric has a significant potential to use as a natural antioxidant agent.Öğe in vitro Antioxidant Activity and Total Phenolic Content of Various Extracts of Satureja hortensis L. Collected from Turkey(Asian Journal Of Chemistry, 2013) Yesiloglu, Yesim; Sit, Latifsah; Kilic, IsmailThe antioxidant capacities of the acetone, ethanol and water extracts of leaves and flowers of S. hortensis were estimated using different antioxidant tests, including lipid peroxidation, reducing power, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, iron chelation, superoxide anion radical scavenging and hydrogen peroxide scavenging. The contents of antioxidant components in these extracts were also determined. Results showed that the highest contents of these components including phenols and flavonoids were found in water extract. This study verified that the water extract has strong antioxidant activities which were correlated with its high level of phenolics and flavonoids. This extract can be used as a source of potential antioxidant or functional food material.Öğe In Vitro Antioxidant Activity of Various Extracts of Ginger (Zingiber officinale L.) Seed(Asian Journal Of Chemistry, 2013) Yesiloglu, Yesim; Aydin, Hatice; Kilic, IsmailThe methanolic and ethanolic extracts from ginger (Zingiber officinale L.) seed (ZOS) were investigated for their antioxidant and radical scavenging activities in eight different assays, namely, total antioxidant activity, reducing power, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, total flavonoid content, total phenolic Compound and metal chelating activities. Both methanolic extract and ethanolic extract of Zingiber officinale L. seed exhibited strong total antioxidant activity. These-various antioxidant activities were compared with synthetic antioxidants such as butylated hydroxyanisole, butylated hydroxytoluene, Trolox, alpha-tocopherol and ascorbic acid. The-Methanol:extract Zingiber officinale L. seed seed exhibited greater antioxidant capacity than that of ethanol.Öğe INVESTIGATION OF ANTIOXIDANT ACTIVITY OF Sorbus domestica L. EXTRACTS AND DETERMINATION OF PHENOLIC CONTENTS BY LC-MS/MS(Editura Acad Romane, 2022) Ceylan, Burhan; Yesiloglu, YesimIn this work, antioxidant activity of the extract Sorbus domestica L. was investigated using different methods. Phenolic contents were assessed using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) technique. Antioxidant activity of S. domestica L. for different radical and compound was assessed. As a result, mountain S. domestica L. water extract showed the best antioxidant effect among other plant extracts tested. According to total antioxidant determination by thiocyanate method, water extract has the highest total antioxidant activity (23.54 mg ascorbic acid g(-1) extract) compared to other extracts. The concentrations of the extracts providing 50% inhibition (IC50 value) of 2,2'-azino-bis(3-ethylbenzothioazoline-6-sulphoic acid) diammonium salt (ABTS(.+)) radical scavenging activity are between 9.14 +/- 0.50 and 10.97 +/- 0.25 mu g mL(-1). It was also seen that extracts exhibit good antioxidant activity; therefore, it can be claimed that S. domestica L. can be used as natural antioxidant source.Öğe Investigation on the Antioxidant Activity of Roots and Stem of Colchicum turcicum L.(Asian Journal Of Chemistry, 2014) Kilic, Ismail; Yesiloglu, Yesim; Bayrak, YukselWater and acetone extracts from Colchicum turcicum L. were investigated for their antioxidant and radical scavenging activities in four different assays, namely, total antioxidant activity, 1,1-dipenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, hydrogen peroxide scavenging and ferrous chelating activities. Antioxidant activity, ferrous chelating and hydrogen peroxide scavenging activities of C. turcicum extracts showed dose dependence and increased with concentration of C. turcicum extract. At the same concentration (100 mu g/mL), water extract of C. turcicum (WECT) and acetone extract of C. turcicum (AECT) showed 53 and 48 % inhibition of lipid peroxidation of linoleic acid emulsion, respectively. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene and ascorbic acid indicated inhibitions of 77, 71 and 59 % on the peroxidation of linoleic acid emulsion, respectively, at 50 mu g/mL. Also, the total phenolic content in both water extract of C. turcicum and acetone extract of C. turcicum were determined as catechol equivalents. The total phenolics content of water and acetone extracts were determined by the Folin-Ciocalteu procedure and 0.454 and 2.172 mg catechol equivalent of phenols was detected in 1 g water extract of C. turcicum and acetone extract of C. turcicum.Öğe Partial purification and characterization of almond seed lipase(Taylor & Francis Inc, 2008) Yesiloglu, Yesim; Baskurt, LalecanA lipase was partially purified from the almond (Amygdalus communis L.) seed by ammonium sulfate fractionation and dialysis. Kinetics of the enzyme activity versus substrate concentration showed typical lipase behavior, with Km and Vmax values of 25mM and 113.63 mu mol min(-1) mg(-1) for tributyrin as substrate. All triglycerides were efficiently hydrolyzed by the enzyme. The partially purified almond seed lipase (ASL) was stable in the pH range of 6-9.5, with an optimum pH of 8.5. The enzyme was stable between 20 and 90 degrees C, beyond which it lost activity progresively, and exhibited an optimum temperature for the hydrolysis of soy bean oil at 65 degrees C. Based on the temperature activity data, the activation energy for the hydrolysis of soy bean oil was calculatedas -5473.6cal/mol. Soy bean oil served as good substrate for the enzyme and hydrolytic activity was enhanced by Ca2+, Fe2+, Mn2+, Co2+, and Ba2+, but strongly inhibited by Mg2+, Cu2+, and Ni2+. The detergents, sodiumdeoxicholate and Triton X-100 strongly stimulated enzyme activity while CTAB, DTAB, and SDS were inhibitors. Triton X-405 had no effect on lipase activity. The partially purified enzyme retained its activity for more than 6 months at -20 degrees C, beyond which it lost activity progressively.Öğe Spectroscopic studies on the antioxidant activity of ellagic acid(Pergamon-Elsevier Science Ltd, 2014) Kilic, Ismail; Yesiloglu, Yesim; Bayrak, YukselEllagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 mu g/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), alpha-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH center dot scavenging, ABTS(center dot+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, alpha-tocopherol and ascorbic acid as references antioxidant compounds. These results' suggested that EA can be used in the pharmacological, food industry and medicine because of these properties. (C) 2014 Elsevier B.V. All rights reserved.Öğe Spectroscopic studies on the antioxidant activity of p-coumaric acid(Pergamon-Elsevier Science Ltd, 2013) Kilic, Ismail; Yesiloglu, Yesimp-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 mu g/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH center dot scavenging, ABTS(center dot+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, alpha-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties. (C) 2013 Elsevier B.V. All rights reserved.
