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Now showing 1 - 10 of 44
  • PublicationMetadata only
    Evaluation of fruit extracts of six Turkish Juniperus species for their antioxidant, anticholinesterase and antimicrobial activities
    (2011-03-30T00:00:00Z) Ozturk, Mehmet; Tumen, Ibrahim; Ugur, Aysel; Aydogmus-Ozturk, Fatma; Topcu, GÜLAÇTI; TOPÇU, GÜLAÇTI
    BACKGROUND: Juniperus L. (Cupressaceae) species are mostly spread out in the Northern Hemisphere of the world, and some of them are used as folkloric medicines. The fruits of some species are eaten. Since oxidative stress is one of the reasons for neurodegeneration and is associated with the Alzheimer-s disease (AD), the extracts prepared from the fruits of six Juniperus species were screened for their antioxidant activity. Therefore, the extracts were also evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), which are chief enzymes in the pathogenesis of AD. In addition, antimicrobial activity was also evaluated.
  • PublicationMetadata only
    Abietane diterpenoids as butyrylcholinesterase inhibitors from Salvia species
    (2012-08-01) Topcu, GÜLAÇTI; Akdemir, ATİLLA; Öztürk, Mahmut Serdar; Boğa, Miray; Kola, U.; TOPÇU, GÜLAÇTI; AKDEMİR, ATİLLA
  • PublicationMetadata only
    Diterpens and other constituens from Ajuga spp. with cytotoxic activity
    (2015-08-01) Yapar, Gönül; Uckaya, FATİH; Topcu, GÜLAÇTI; UÇKAYA, FATİH; TOPÇU, GÜLAÇTI
  • PublicationMetadata only
    Complete C-13 NMR assignments for ent-kaurane diterpenoids from Sideritis species
    (2011-05-01T00:00:00Z) Halfon, Belkis; GOREN, AHMET CEYHAN; Ertas, Abdulselam; Topcu, GÜLAÇTI; GÖREN, AHMET CEYHAN; TOPÇU, GÜLAÇTI
    In this work, the detailed NMR studies and full C-13 NMR assignments for five diterpenoids isolated from Sideritis caesarea and Sideritis athoa are described. The assignments are based on a combination of 1D and 2D NMR techniques including H-1, C-13, H-1-H-1 COSY, gHSQC [(1)J(C,H)] and gHMBC delta(C) [(n)J(C,H) (n = 2 and 3)] and NOESY experiments. Copyright (C) 2011 John Wiley & Sons, Ltd.
  • PublicationMetadata only
    Tyrosinase Inhibitory Activity of Chemical Constituents of Euphorbia macrostegia
    (2014-11-01) Demirkiran, Ozlem; Topcu, GÜLAÇTI; AZARPIRA, Ali; CHOUDHARY, M. Iqbal; TOPÇU, GÜLAÇTI
    The chloroform extract of the aerial parts of E. macrostegia has yielded a new compound, 2-(4-hydroxyphenyl)-ethylhentriacontanoate (1), along with hentriacontan-1-ol (2), lupenone (3), cycloart-22-ene-3,25-diol (4), 3,3-,4--tri-O-methylellagic acid (5), cleomiscosin (6), and glucoclioniasterol (stigmast-5-en-3-O-beta-glucopyranoside) (7), and from the ethyl acetate extract of aerial parts of the plant isoquercetin (8), quercetin-3-O-alpha-arabinofuranoside (avicularin) (9), and rutin (10) have been isolated. Compounds 1-10 were tested for their tyrosinase inhibitory activity, and 2 exhibited an IC50 value of 71.4 mu M, almost comparable to standard kojic acid (IC50 58.2 mu M). Compounds 1-4 also showed good activity with IC50 values of 77.2, 78.6, 71.4, and 77.5 mu M, respectively.
  • PublicationMetadata only
    Screening of Hallucinogenic Compounds and Genomic Characterisation of 40 Anatolian Salvia Species
    (2017-11-01T00:00:00Z) HATIPOGLU, Seda Damla; YALCINKAYA, Burhanettin; AKGOZ, Muslum; OZTURK, Turan; Goren, AHMET CEYHAN; Topcu, GÜLAÇTI; GÖREN, AHMET CEYHAN; TOPÇU, GÜLAÇTI
    Introduction - Salvia, an important and widely available member of Lamiaceae family. Although comparative analysis on secondary metabolites in several Salvia species from Turkey has been reported, their hallucinogenic chemicals have not been screened thoroughly.
  • PublicationMetadata only
    Chemical Profile and Biological Activities of Two Edible Plants: Chemical Investigation and Quantitative Analysis Using Liquid Chromatography Tandem Mass Spectrometry and Gas Chromatography Mass Spectrometry
    (2016-01-02) Ertas, Abdulselam; Yilmaz, Mustafa Abdullah; Boga, Mehmet; Hasimi, Nesrin; Yesil, Yeter; GOREN, Ahmet C.; Temel, Hamdi; Topcu, GÜLAÇTI; GÖREN, AHMET CEYHAN; TOPÇU, GÜLAÇTI
    The objectives of this study were to define the phenolic and fatty acid profiles, anticholinesterase, antioxidant, antimicrobial activities, and total phenolic-flavonoid contents of Lycopsis orientalis and Tragopogon latifolius var. angustifolius which have been used as food source and food supplement in Anatolia and have never been examined before. Rosmarinic and quinic acids (21.11 and 11.46 mg g(-1) extract, respectively) were found to be the most abundant constituents in L. orientalis and T. latifolius var. angustifolius among the studied 27 compounds by liquid chromatography tandem mass spectrometry. In the fatty acid compositions of L. orientalis and T. latifolius var. angustifolius that were determined by gas chromatography mass spectrometry, oleic (29.1%) and palmitic (28.7%) acids were identified as the major components, respectively. The high antioxidant activity of the methanol extract of L. orientalis shows parallelism to its rosmarinic acid content. Besides, this extract showed medium anticholinesterase activity. The results of the present study proves that the L. orientalis might also be used as a food source due to its high phenolic acid content and strong antioxidant property.
  • PublicationMetadata only
    A promising novel antidiabetic compound: Alysine-A
    (2016-09-01) Sen, A.; Ayar, B.; Topcu, GÜLAÇTI; Yilmaz, ANIL; TOPÇU, GÜLAÇTI; YILMAZ, ANIL
  • PublicationMetadata only
    Two New Phenylpropanoid Glycosides from the Leaves and Flowers of Erica arborea
    (2010-01-01T00:00:00Z) Demirkiran, Ozlem; Topcu, GÜLAÇTI; Bahadori, Fatemeh; AY, MEHMET; NAZEMIYEH, Hossein; CHOUDHARY, Iqbal; TOPÇU, GÜLAÇTI; BAHADORİ, FATEMEH
    Two new phenylpropanoid glucosides, 1,2-erythro-1-(3,4,5-trimethoxyphenyl)-2-(beta-D-glucopyranosyloxy)propan-1,3-diol (1) and 7,8-threo-2-,8-epoxysyringylglycerol-7-O-alpha-D-glucopyranoside (ericarboside; 2) have been isolated together with four known compounds 2-,7-epoxysyringylglycerol-8-O-beta-D-glucopyranoside (ficuscarpanoside B; 3), benzylrutinoside (hydrangeifolin; 4), phenethylrutinoside (5), and caffeic acid from the BuOH soluble part of the MeOH extract of the leaves and flowers of E. arborea L. Final purification of the compounds was achieved on a reversed-phase HPLC. Their structures have been elucidated by extensive 1D- and 2D-NMR, and mass spectroscopic techniques.
  • PublicationMetadata only
    Ent-kaurane diterpenoids isolated from Sideritis congesta
    (2011-12-01) Topcu, GÜLAÇTI; Ertas, Abdulselam; Ozturk, Mehmet; Dincel, Demet; Kilic, Turgut; Halfon, Belkis; TOPÇU, GÜLAÇTI; DİNCEL, DEMET
    A new ent-kaurane diterpenoid, together with eight known ent-kauranes, were isolated from the petroleum ether and acetone extracts of the whole plant of Sideritis congesta P. H. Davis & Hub.-Mor. and their structures were elucidated as the new compound ent-7 alpha-acetoxy-16 beta, 18-dihydroxy-kaurane (7-acetyldistanol) (1) and the known compounds ent-3 beta,7 alpha-dihydroxy, 18-acetoxy-15 beta,16 beta-epoxykaurane (epoxyisolinearol) (2), sideroxol (3), sideridiol (4), siderol (5), 7-epicandicandiol (6), foliol (7), linearol (8) and sidol (9). Characterization of compounds 1-9 was based on spectral analyses and comparison with reported data, particularly the new compound 1 was identified by 1D- and 2D-NMR and mass spectroscopic analyses. The antioxidant potential of the extracts, and also of the ent-kauranes except for 7, was investigated by three methods including beta-carotene bleaching method, free radical scavenging activity and superoxide anion scavenging activity. The anticholinesterase activity was also evaluated for the ent-kauranes except for 7, and most of the diterpenes exhibited weak acetylcholinesterase inhibitory activity. However, almost all diterpenes exhibited some inhibitory activity against butyrylcholinesterase; particularly, compounds 3 and 6 exhibited better BChE inhibitory activity than the standard compound galanthamine. (C) 2011 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.