Browsing by Author "Tepe B."
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Item Studies on the antioxidant activity of essential oil and different solvent extracts of Vitex agnus castus L. fruits from Turkey(2009) Sarikurkcu C.; Arisoy K.; Tepe B.; Cakir A.; Abali G.; Mete E.This study is designed to examine the chemical composition and antioxidant activity of the essential oil and different solvent extracts of Vitex agnus castus. GC and GC-MS analysis was resulted in the detection of 27 components, representing 94.5% of the oil. Major components of the oil were 1,8-cineole (24.98%), sabinene (13.45%), α-pinene (10.60%), α-terpinyl acetate (6.66%), and (Z)-β-farnesene (5.40%). Antioxidant activities of the samples were determined by three different test systems, DPPH, β-carotene/linoleic acid and reducing power assays. In all systems, water extract exhibited excellent activity potential than those of other extracts (hexane, dichloromethane, ethyl acetate and methanol) and the oil. As expected, amount of total phenolics was very high in this extract (112.46 ± 1.22 μg GAEs/mg extract). Dichloromethane extract has been found to be rich in flavonoids. A positive correlation was observed between the antioxidant activity potential and total phenolic and flavonoid levels of the extracts. © 2009 Elsevier Ltd. All rights reserved.Item Essential oil composition and antioxidant activities of alkanet (Alkanna tinctoria subsp. tinctoria)(2010) Ozer M.S.; Sarikurkcu C.; Tepe B.; Can S.This study is designed to examine the chemical composition and in vitro antioxidant activity of the hydrodistillated essential oil and the various extracts of alkanet (Alkanna tinctoria subsp. tinctoria). Gas chromatography (GC) and GC-mass spectrometry (GC-MS) analysis of the essential oil were resulted in the determination of 27 different compounds, representing 93.32% of the total oil. The major compounds detected in the oil, were pulegone (22.27%), 1,8-cineole (13.03%), α-terpinyl acetate (6.87%), and isophytol (6.83%), respectively. Antioxidant activities of the samples were determined by 4 different test systems namely β-carotene/linoleic acid, 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing power, and chelating effect. In all systems, essential oil showed the weakest activity profile. On the other hand, ethyl acetate and water extracts exhibited excellent antioxidant activities. As well as the antioxidant activities of the extracts, they were evaluated in terms of their total phenolic and flavonoid contents. In parallel to the experiments, ethyl acetate and water extracts were found to be rich-in these phytochemicals. © KoSFoST and Springer 2010.Item Essential oil composition and antioxidant activity of Thymus longicaulis C. Presl subsp. longicaulis var. longicaulis(2010) Sarikurkcu C.; Sabih Ozer M.; Eskici M.; Tepe B.; Can Ş.; Mete E.This study is designed to examine the chemical composition and in vitro antioxidant activity of the hydrodistillated essential oil and various extracts obtained from Thymus longicaulis subsp. longicaulis var. longicaulis. GC and GC-MS analysis of the essential oil were resulted in determination 22 different compounds, representing 99.61% of total oil. γ-terpinene, thymol and p-cymene were determined as the major compounds of the oil (27.80, 27.65 and 19.38%, respectively). Antioxidant activities of the samples were determined by four different test systems namely β-carotene/linoleic acid, DPPH, reducing power and chelating effect. Essential oil showed the highest antioxidant activity in β-carotene/linoleic acid system among the experiments examined. In the case of other test systems, in general, methanol and water extracts exhibited the strongest activity profiles. Especially, reducing power of water extract was found superior than those of synthetic antioxidants. As well as the antioxidant activities of the extracts, they were evaluated in terms of their total phenolic and flavonoid contents. Hexane and water extracts were found to be rich-in phenolics. However, flavonoids were determined in the highest level in methanol extract. © 2010 Elsevier Ltd.Item Phenolic composition, antioxidant and enzyme inhibitory activities of acetone, methanol and water extracts of Clinopodium vulgare L. subsp. vulgare L.(Elsevier, 2015) Sarikurkcu C.; Ozer M.S.; Tepe B.; Dilek E.; Ceylan O.The aim of this study is to evaluate the antioxidant and enzyme inhibitory activities of acetone, methanol and water extracts of Clinopodium vulgare L. subsp. vulgare L. as well as its phytochemical composition. Methanol extract was found rich in of phenolic compounds (44.42. mg GAEs/g extract) whereas the highest flavonoid content was determined in the water extract (40.20. mg REs/g extract). Methanol extract was also found rich in protocatechuic acid, (+)-catechin, chlorogenic acid, caffeic acid, ferulic acid, rosmarinic acid and apigenin. Data obtained from the phosphomolybdenum assay was found in correlation with those obtained from total phenolic assay. Methanol extract exhibited the highest activity (374.86. mmol TEs/g extract). In the case of chelating effect assay, acetone extract exhibited the highest activity. As observed in many previously reported studies, water extract exhibited the highest DPPH free radical scavenging activity (81.72. mg TEs/g extract). ABTS cation scavenging assay was resulted in the superiority of methanol extract (51.45. mg TEs/g extract). It also showed the strongest reducing power in CUPRAC and FRAP assays. Acetone extract exhibited remarkable inhibitory activity on acetylcholinesterase, butyrylcholinesterase and tyrosinase, while the highest α-amylase and α-glucosidase inhibitory activities were exhibited by methanol and water extracts. Total amounts of unsaturated fatty acids were determined as 51.15%. C18:1 ω9, C18:2 ω6 and C18:3 ω3 were determined in considerable quantities (23.93, 6.18 and 5.78%, respectively). © 2015 Elsevier B.V.Item Phenolic composition, antioxidant and enzyme inhibitory activities of ethanol and water extracts of: Chenopodium botrys(Royal Society of Chemistry, 2016) Ozer M.S.; Sarikurkcu C.; Tepe B.In this study, we aimed to evaluate the phenolic composition, antioxidant, and enzyme inhibitory activities of ethanol and water extracts of Chenopodium botrys L. In the ethanol extract, the amounts of flavonoids, saponins, and condensed tannins were found to be higher than those of the water extract (4.54 mg of rutin equivalent (RE) per g of dry plant, 25.45 mg of quillaja equivalent (QAE) per g of dry plant, and 59.20 mg of catechin equivalent (CE) per g of dry plant, respectively). On the other hand, a total phenolic assay showed a superiority of the water extract (3.85 mg of gallic acid equivalent (GAE) per g of dry plant). The extracts were also subjected to screening for the quantification of selected compounds. Among the compounds, benzoic acid was found to be the most abundant one in the extracts (59.93 and 2974.24 μg per g of dry plant, respectively). In general, antioxidant activity assays showed the superiority of the water extract. C. botrys extracts were also evaluated for their inhibitory activities on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase, and α-glucosidase. The water extract exhibited the highest inhibitory activity on AChE, tyrosinase, α-amylase, and α-glucosidase (113.69 μg of galantine equivalent (GALAE) per g of dry plant, 165.56 μg of kojic acid equivalent (KAE) per g of dry plant, 7.16 mg of acarbose equivalent (ACE) per g of dry plant, and 6.47 mg of ACE per g of dry plant, respectively). On the other hand, BChE inhibitory activity of the ethanol extract was found to be higher than that of the water extract (60.90 μg of GALAE per g of dry plant). According to the results of the antioxidant and enzyme inhibitory activity assays, C. botrys may have the potential to prevent diseases associated with oxidative stress and to prevent AD, pigmentation diseases, hyperglycaemia and its associated complications. © The Royal Society of Chemistry 2016.Item Fatty acid composition, enzyme inhibitory, and antioxidant activities of the ethanol extracts of selected wild edible plants consumed as vegetables in the Aegean region of Turkey(Taylor and Francis Inc., 2017) Sarikurkcu C.; Targan S.; Ozer M.S.; Tepe B.The aim of this study was to evaluate the fatty acid composition, enzyme inhibitory, and antioxidant activities of the ethanol extracts of selected wild edible plants consumed as vegetable in the Aegean region of Turkey. In general, Mentha piperita L., Rumex patientia L., and R. acetosella L. exhibited quite strong antioxidant activities in the majority of test systems, whereas Urtica dioica L. and Eruca sativa Mill. show quite weak antioxidant activities. Enzyme inhibitory activities of the plants were found quite different than those of their antioxidant activities. Cardaria draba (L.) Desv., E. sativa, R. patientia, and E. cicutarium (L.) L’Hér. showed the highest inhibitory activities on acetylcholinesterase, butyrylcholinesterase, α-amylase, and α-glucosidase, respectively. U. dioica also showed a promising inhibitory activity on these enzymes. In parallel to the experiments, total phenolic, flavonoid, flavonol, and saponin contents of the extracts were also determined. According to the results of these assays, M. piperita had the highest amounts of phenolics, flavonols, and saponins (162.36 mg gallic acid equivalents/g extract, 3.52 mg CEs/g extract and 761.54 mg QAEs/g extract, respectively). Opopanax hispidus (Friv.) Griseb. and Lepidium sativum L. were found to be rich in flavonoid compounds (121.18 and 104.21 mg Res/g extract, respectively). In general, a strong correlation was determined between the phytochemical profile and antioxidant activity of the plant species. © 2017 Taylor & Francis Group, LLC.Item A comprehensive study on chemical composition, antioxidant and enzyme inhibition activities of the essential oils of Chenopodium botrys collected from three different parts of Turkey(Elsevier B.V., 2017) Ozer M.S.; Sarikurkcu C.; Ceylan O.; Akdeniz I.; Tepe B.In this study, we aimed to evaluate the chemical composition of the essential oil of Chenopodium botrys L. collected from three different parts of Turkey. Additionally, we analyzed the antioxidant activities of the oil samples by using free radical scavenging, phosphomolybdenum, ferrous ion chelating, and reducing power assays as well as their inhibitory activities on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase. According to the results of GC-FID and GC–MS analyses, twenty-seven, twenty-four, and sixteen compounds were identified representing 94.45%, 96.96%, and 94.41% of the oils, respectively. In Afyonkarahisar and Isparta samples, ledol (25.11% and 22.73%), elemol (15.25% and 24.86%), and germacrene D-4-ol (14.83% and 11.27%) were determined as the major compounds, whereas ledol (31.83%), elemol (23.70%), and eudesm-7(11)-en-4-ol (8.94%) were found as the main compounds of Konya sample. The oil of Isparta sample showed the maximum radical scavenging activity in all test systems, except superoxide anion radical scavenging assay. Phosphomolybdenum, ferrous ion chelating, and reducing power assays were resulted in the superiority of Afyonkarahisar sample. In AChE and tyrosinase inhibition assays, the essential oil of C. botrys collected from Konya showed the maximum activity (0.87 mg GALAEs/g oil and 0.82 mg KAEs/g oil, respectively). On the other hand, BChE inhibition assay was resulted in the superiority of Afyonkarahisar sample (1.02 mg GALAEs/g oil). In order to determine the contribution of oil components to the biological activity, correlation coefficients between the compounds and assays were also presented. © 2017Item Onosma heterophyllum: Phenolic composition, enzyme inhibitory and antioxidant activities(Elsevier B.V., 2018) Ozer M.S.; Kirkan B.; Sarikurkcu C.; Cengiz M.; Ceylan O.; Atılgan N.; Tepe B.Onosma species have frequently been used for their colouring and dyeing properties in foods and medicinal preparations. The antioxidant and enzyme inhibitory activities of the ethyl acetate, methanol and water extracts of Onosma heterophyllum (Griseb.) are described. Phytochemical compositions of these extracts were also determined. The water extract showed not only remarkable antioxidant activity in all assays but also considerable inhibitory activity on tyrosinase and α-glucosidase (112.44 μmol KAEs/g dry plant and 984.36 μmol ACEs/g dry plant, respectively). The methanol extract exhibited the highest inhibitory activity on acetylcholinesterase (AChE) and α-amylase (79.18 μmol GALAEs/g dry plant and 10.42 μmol ACEs/g dry plant, respectively). Chromatographic analyses revealed that the water extract was found to be rich in phenolic and flavonoid contents. On the basis of the correlation coefficients calculated separately for all experimental parameter pairs, protocatechuic acid, p-hydroxybenzoic acid, syringic acid, p-coumaric acid and luteolin were found to be highly in correlation with the antioxidant and enzyme inhibitory activities. This study demonstrates that O. heterophyllum, contained in food preparations with various purposes for many years, could be used for the treatment of diabetes as well as its skin whitening effect. © 2017 Elsevier B.V.Item Chemical characterization and biological activity of Onosma gigantea extracts(Elsevier B.V., 2018) Sarikurkcu C.; Kirkan B.; Ozer M.S.; Ceylan O.; Atilgan N.; Cengiz M.; Tepe B.Onosma species have traditionally been used as laxative and anthelmintic agents as well as their uses in eye, blood diseases, bronchitis, abdominal pain, strangury, thirst, itch, leucoderma, fever, wounds, burns, piles, and urinary calculi. This study examines the investigation of biological activities of ethyl acetate, methanolic, and aqueous extracts from Onosma gigantea Lam. The extracts were evaluated for the antioxidant and enzyme inhibitory activities. Phenolic compounds in the extracts were also detected by RP-HPLC-DAD. The aqueous extract showed remarkable antioxidant activity in phosphomolybdenum [134.31 μmol trolox equivalents (TEs)/g air dry matter (adm)], chelating effect [32.97 μmol ethylenediaminetetraacetic acid (disodium salt) equivalents (EDTAEs)/g adm], radical scavenging [on DPPH (32.14 μmol TEs/g adm) and ABTS (58.68 μmol TEs/g adm)], and reducing power [CUPRAC (50.23 μmol TEs/g adm) and FRAP (40.96 μmol TEs/g adm)] assays. The aqueous extract also exhibited considerable inhibitory activity of tyrosinase (10.48 μmol kojic acid equivalents/g adm) and α-glucosidase [1320.53 μmol acarbose equivalents (ACEs)/g adm]. It has been determined that the methanolic extract showed significant AChE (31.57 μmol galanthamine equivalents (GALAEs)/g adm) and α-amylase (6.75 μmol ACEs/g adm) inhibitory activity. The ethyl acetate, which contains low polarity compounds, showed the highest BChE inhibitory activity (6.87 μmol GALAEs/g adm). In general, it is found that there is a positive correlation between the phytochemical contents of the extracts and their biological activities. The results indicate that O. gigantea extracts could be considered as a novel source of bioactive agents with functional connections. © 2018 Elsevier B.V.Item Can the stalks of Papaver somniferum L. be an alternative source of bioactive components?(Elsevier B.V., 2018) Kirkan B.; Ozer M.S.; Sarikurkcu C.; Copuroglu M.; Cengiz M.; Tepe B.Alternative raw materials for designing novel products are gaining interest in the scientific area. The aim of this study is to investigate the antioxidant and enzyme inhibitory activities of the extracts obtained from Papaver somniferum L. stalks as well as the determination of chemical composition. Antioxidant capacity was tested by using different chemical methods including radical scavenging, reductive effect, phosphomolybdenum and metal chelating assays. Enzyme inhibitory effect was investigated against cholinesterase, tyrosinase, α-amylase and α-glucosidase. To detect chemical composition, phenolic profile was determined by high performance liquid chromatography (HPLC) as well as total contents of the phytochemicals. The aqueous extract was found to contain high amount of phenolics and flavonoids [9.87 μmol gallic acid equivalents (GAEs)/g dry plant (dp) and 0.09 μmol rutin equivalents (REs)/g dp, respectively]. The methanol and aqueous extracts were also found to contain considerable amounts of (−)-epicatechin and syringic acid. Antioxidant activity tests were resulted in the superiority of the methanol extract. The extracts did not show inhibitory activity on cholinesterases and tyrosinase. Inhibitory activity of the aqueous extract on α-amylase and α-glucosidase were found to be 9.85 and 78.64 μmol acarbose equivalents (ACEs)/g dp, respectively. As a result, P. somniferum stalks, one of the major by-products of poppy cultivation, can be used as the alternative source of antioxidant and enzyme inhibitory compounds in food and medical industries. © 2018 Elsevier B.V.Item Phenolic profile, antioxidant and enzyme inhibitory potential of Onosma tauricum var. tauricum(Elsevier B.V., 2018) Kirkan B.; Sarikurkcu C.; Ozer M.S.; Cengiz M.; Atılgan N.; Ceylan O.; Tepe B.This study focused on phytochemical characterization and biological evaluation, both antioxidant and enzymatic inhibition, of ethyl acetate (OTT-EtOAc), methanol (OTT-MeOH), and water (OTT-W) extracts from Onosma tauricum var. tauricum aerial parts. The OTT-W extract was found to be the richest one in terms of its phenolic and flavonoid contents. Amounts of the phenolic and flavonoid compounds were determined as 40.88 μmol GAEs/g and 7.40 μmol REs/g dry plant (dp), respectively. The OTT-MeOH and OTT-W extracts were also found to contain significant amounts of chlorogenic acid, rosmarinic acid, p-hydroxybenzoic acid, caffeic acid, rutin, p-coumaric acid, trans-cinnamic acid, luteolin, and apigenin. The OTT-W extract showed remarkable antioxidant activity in phosphomolybdenum, ferrous ion chelating, reducing power, and radical scavenging assays. The OTT-MeOH extract exhibited inhibitory activity on acetylcholinesterase (AChE) (54.62 μmol GALAEs/g dp), while the extracts remained almost inactive on butyrylcholinesterase (BChE). The OTT-W extract also exhibited inhibitory activity on tyrosinase (90.66 μmol KAEs/g dp) and α-glucosidase (2258.87 μmol ACEs/g dp). The results suggest that especially the OTT-MeOH and OTT-W extracts can be used as a source of alternative natural products in the treatment of diseases caused by the enzymes evaluated here. © 2018 Elsevier B.V.Item Phenolic profile, enzyme inhibitory and antioxidant activities of two endemic Nepeta species: Nepeta nuda subsp. glandulifera and N. cadmea(Elsevier B.V., 2019) Sarikurkcu C.; Eskici M.; Karanfil A.; Tepe B.It is known that the local people commonly use some Nepeta species as diuretic, spasmolytic, bronchodilator and sedative agents. In addition, these species are also used topically due to their antiseptic properties. This study aimed to deal with the in vitro antioxidant and enzyme inhibitory activities of the methanolic extracts of two endemic. Nepeta species (Nepeta nuda L. subsp. glandulifera Hub.-Mor. & Davis and N. cadmea Boiss.) from Turkey. N. nuda subsp. glandulifera was found to contain more phenolics and flavonoids than N. cadmea. N. nuda subsp. glandulifera was also found to have considerable amounts of chlorogenic and ferulic acids (63.52 and 14.65 mg/g extract), and showed higher antioxidant activity in almost all test systems, except metal chelating assay. Meanwhile in β-carotene bleaching assay, it was found to be as active as BHT and trolox (91.23%). In the enzyme inhibition assay, the extracts showed weak inhibitory activity on AChE, α-amylase and α-glucosidase. Inhibitory activity of N. nuda subsp. glandulifera on these enzymes was found to be 1.26 mg GALAEs (galanthamine equivalents)/g extract, 0.36 and 3.67 mmol ACEs (acarbose equivalents)/g extract, respectively. © 2018 South African Association of BotanistsItem Enzyme and biological activities of the water extracts from the plants aesculus hippocastanum, olea europaea and hypericum perforatum that are used as folk remedies in Turkey(MDPI AG, 2020) Sarikurkcu C.; Locatelli M.; Tartaglia A.; Ferrone V.; Juszczak A.M.; Ozer M.S.; Tepe B.; Tomczyk M.Phenolic compounds are secondary metabolites that are found ubiquitously in plants, fruits, and vegetables. Many studies have shown that regular consumption of these compounds could have a positive effect on our health. The aim of this study was to compare the phytochemical contents of the water extracts from three different plants used as folk remedies in Turkey: Aesculus hippocastanum, Olea europaea, and Hypericum perforatum. A liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) analysis was performed to explore the phenolic profiles. The biological activities of these extracts were also evaluated in terms of their antioxidant activities (2,2-diphenyl-1-picrylhydrazyl DPPH, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid ABTS, Ferric Reducing Antioxidant Power Assay FRAP, cupric ion reducing antioxidant capacity CUPRAC, β-carotene, phosphomolybdenum, and metal chelating) and enzyme inhibitory properties (against acetylcholinesterase, butyrylcholinesterase, and tyrosinase). The aqueous extract of H. perforatum showed the highest levels of total phenolic, flavonoid, and saponin contents. Protocatechuic acid, vanillic acid, verbascoside, hesperidin, hyperoside, apigenin 7-hexosides, and quercetin were the most common compounds found in this species. The results confirm that A. hippocastanum, O. europaea, and H. perforatum represent a potential source of natural-derived molecules with positive properties that could be used as valid starting point for new food supplements, and drugs in the pharmaceutical, cosmetic, and food industries. © 2020 by the authors.Item Chromatographic profile and antioxidant and enzyme inhibitory activity of Sideritis leptoclada: An endemic plant from Turkey(Elsevier B.V., 2021) Sarikurkcu C.; Ozer M.S.; Istifli E.S.; Sahinler S.S.; Tepe B.Sideritis species have been used for centuries for their antimicrobial, digestive, anti-ulcerogenic and anti-inflammatory properties. Therefore, in this study, it was aimed to evaluate the chemical composition, antioxidant and enzyme inhibitory activities of solvent extracts of S. leptoclada O. Schwarz & P.H. Davis, an endemic species. It was determined that methanol (MeOH) and water extracts contained high amounts of chlorogenic acid and verbascoside, while the ethyl acetate (EtOAc) extract contained high amounts of 4-hydroxybenzoic and vanilic acids. The water extract showed the highest antioxidant activity in almost all parameters. Inhibitory activity of the MeOH extract on tyrosinase was 1.04 mg/ml, which was the highest value in this experiment. On the other hand, in α-amylase inhibitory assay, the EtOAc extract showed an activity of 2.21 mg/ml. Docking analysis showed that verbascoside can be an effective tyrosinase and α-amylase inhibitory agent. © 2021 SAAB