Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Ayşen Özdemir Türk is active.

Publication


Featured researches published by Ayşen Özdemir Türk.


Zeitschrift für Naturforschung C | 2004

Evaluation of the antimicrobial activity of the acetone extract of the lichen Ramalina farinacea and its (+)-usnic acid, norstictic acid, and protocetraric acid constituents.

Turgay Tay; Ayşen Özdemir Türk; Meral Yılmaz; Hayrettin Türk; Merih Kivanç

The acetone extract of the lichen Ramalina farinacea and its (+)-usnic acid constituent showed antimicrobial activity against Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Staphylococcus aureus, Streptococcus faecalis. Yersinia enterocolitica, Candida albicans, and Candida glabrata. Norstictic acid was active against Aeromonas hydrophila as well as the above microorganisms except Yersinia enterocolitica. Protocetraric acid showed activity only against the tested yeasts Candida albicans and Candida glabrata. The MIC values of the extract as well as of the three substances were determined. No antifungal activity of the acetone extract has been observed against ten filamentous fungi.


Zeitschrift für Naturforschung C | 2004

The antimicrobial activity of extracts of the lichen Cladonia foliacea and its (-)-usnic acid, atranorin, and fumarprotocetraric acid constituents.

Meral Yılmaz; Ayşen Özdemir Türk; Turgay Tay; Merih Kivanç

The antimicrobial activity of the chloroform, diethyl ether, acetone, petroleum ether, and ethanol extracts of the lichen Cladonia foliacea and its (-)-usnic acid, atranorin, and fumarprotocetraric acid constituents against 9 bacteria and fungi has been investigated. The extracts and pure compounds alone were found active against the same bacteria and the same yeasts. Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Proteus vulgaris, Listeria monocytogenes, Aeromonas hydrophila, Candida albicans, and Candida glabrata growth were inhibited. In addition, the MICs of the extracts, (-)-usnic acid, atranorin and fumarprotocetraric acid were determined.


Zeitschrift für Naturforschung C | 2006

Antimicrobial activity of extracts of chemical races of the lichen Pseudevernia furfuracea and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents.

Hayrettin Türk; Meral Yılmaz; Turgay Tay; Ayşen Özdemir Türk; Merih Kivanç

The antimicrobial activity and the MIC values of the ethanol, chloroform, diethyl ether, and acetone extracts of the chemical races of Pseudevernia furfuracea (var. furfuracea and var. ceratea) and their physodic acid, chloroatranorin, atranorin, and olivetoric acid constituents have been investigated against some microorganisms. Nearly all extracts of both chemical races showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Staphylococcus aureus, Streptococcus faecalis, Yersinia enterocolitica, Candida albicans, Candida glabrata, Alternaria alternata, Ascochyta rabiei, Aspergillus niger, Fusarium culmorum, Fusarium moniliforme, Fusarium oxysporum, Fusarium solani, and Penicillium notatum. There was no antimicrobial activity of the extracts against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pseudomonas syringae, Salmonella typhimurium, Alternaria citri, Alternaria tenuissima, and Gaeumannomyces graminis. Chloroatranorin and olivetoric acid were active against the same microorganisms with few exceptions. Physodic acid was active against about the same bacteria and yeasts and inactive against all of the filamentous fungi tested. Also no activity of atranorin against the filamentous fungi was observed.


Zeitschrift für Naturforschung C | 2007

Antimicrobial Activity of Extracts of the Lichen Parmelia sulcata and its Salazinic Acid Constituent

Mehmet Candan; Meral Yılmaz; Turgay Tay; Murat Erdem; Ayşen Özdemir Türk

The antimicrobial activity of the acetone, chloroform, diethyl ether, methanol, and petroleum ether extracts of the lichen Parmelia sulcata and its salazinic acid constituent have been screened against twenty eight food-borne bacteria and fungi. All of the extracts with the exception of the petroleum ether extract showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Proteus vulgaris, Yersinia enterocolitica, Staphylococcus aureus, Streptococcus faecalis, Candida albicans, Candida glabrata, Aspergillus niger, Aspergillus fumigatus, and Penicillium notatum. Salazinic acid did not show antimicrobial activity against L. monocytogenes, P. vulgaris, Y. enterocolitica, and S. faecalis but showed activity against Pseudomonas aeruginosa and Salmonella typhimurium as well. The MIC values of the extracts and the acid for the bacteria and fungi have also been determined


Phytotherapy Research | 2009

Angiogenesis inhibition by a lichen compound olivetoric acid

A. Tansu Koparal; Gönül Ulus; Melih Zeytinoglu; Turgay Tay; Ayşen Özdemir Türk

Lichens have been used in folk medicine for centuries and are symbiotic organisms of fungi and algae that produce unique secondary metabolites. Olivetoric acid is one of these secondary metabolites. In the present study, the effect of olivetoric acid isolated from acetone extract of the lichen Pseudevernia furfuracea (var. ceratea) on angiogenesis was evaluated. It displayed potent anti‐angiogenic activities in vitro: inhibited proliferation of rat adipose tissue endothelial cells (RATECs) and disrupted endothelial tube formation in a dose‐dependent manner. Furthermore, dose‐dependent depolymerization effects of olivetoric acid on F‐actin stress fibers were observed. Decrease in the tube formation of RATECs by olivetoric acid might be explained by a disorganization of the actin cytoskeleton. These findings suggest that olivetoric acid is a new anti‐angiogenic agent and can be developed as a new therapeutic agent for angiogenesis‐related diseases. Copyright


Zeitschrift für Naturforschung C | 2005

The Antimicrobial Activity of Extracts of the Lichen Hypogymnia tubulosa and Its 3-Hydroxyphysodic Acid Constituent

Meral Yılmaz; Turgay Tay; Merih Kivanç; Hayrettin Türk; Ayşen Özdemir Türk

The antimicrobial activity and the MIC values of the diethyl ether, acetone, chloroform, petroleum ether, and ethanol extracts of the lichen Hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent have been investigated against some microorganisms. At least one of the extracts or 3-hydroxyphysodic acid showed antimicrobial activity against Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Proteus vulgaris, Salmonella typhimurium, Staphylococcus aureus, Streptococcus faecalis, and Candida albicans. No antifungal activity of the extracts has been observed against ten filamentous fungi.


Fungal Diversity | 2010

A new lichenicolous species of Capronia (Ascomycota, Herpotrichiellaceae), with a key to the known lichenicolous species of the genus

M. Gökhan Halici; David L. Hawksworth; Mehmet Candan; Ayşen Özdemir Türk

A new lichenicolous fungus in the genus Capronia is described: C. minutosetosa sp. nov. from the thallus of Chromatochlamys muscorum in Turkey and Spain. The new species differs from those previously recognized in the genus in the size and septation of the ascospores and peridial setae, as well as in occurring on unrelated hosts. A key to the eleven lichenicolous species of the genus now known is also presented.


Phytotherapy Research | 2016

Photoprotective Activity of Vulpinic and Gyrophoric Acids Toward Ultraviolet B‐Induced Damage in Human Keratinocytes

Mehmet Varol; Ayşen Özdemir Türk; Mehmet Candan; Turgay Tay; Ayşe Tansu Koparal

Vulpinic and gyrophoric acids are known as ultraviolet filters for natural lichen populations because of their chemical structures. However, to the best of our knowledge, there has been no reference to their cosmetic potential for skin protection against ultraviolet B (UVB)‐induced damage and, consequently, we propose to highlight their photoprotective profiles in human keratinocytes (HaCaT). Therefore, vulpinic acid and gyrophoric acid were isolated from acetone extracts of Letharia vulpina and Xanthoparmelia pokornyi, respectively. Their photoprotective activities on irradiated HaCaT cells and destructive effects on non‐irradiated HaCaT cells were compared through in vitro experimentation: 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide and lactate dehydrogenase assays, 4′,6‐diamino‐2‐phenylindole and tetramethylrhodamine B isothiocyanate‐phalloidin staining protocols. Both of the lichen substances effectively prevented cytotoxic, apoptotic and cytoskeleton alterative activities of 2.5 J/cm2 UVB in a dose‐dependent manner. Moreover, vulpinic and gyrophoric acids showed no toxic, apoptotic or cytoskeleton alterative effects on non‐irradiated HaCaT cells, except at high doses (≥400 μM) of gyrophoric acid. The findings suggest that vulpinic and gyrophoric acids can be promising cosmetic ingredients to photo‐protect human skin cells and should therefore be further investigated by in vitro and in vivo multiple bioassays. Copyright


Archive | 2015

Epiphytic Lichen Diversity of the Sündiken Mountains (Eskişehir, Turkey)

Yılmaz Yavuz; Ayşen Özdemir Türk; Harun Böcük

Abstract: Yavuz, Y., Özdemir Türk, A. & Böcük, H. 2015. Epiphytic lichen diversity of the Sündiken Mountains (Eskişehir, Turkey). — Herzogia 28: 753 –761. Ninety-three lichen taxa belonging to 43 genera are recorded from the Sündiken Mountains, Eskişehir (Turkey), of which 34 are reported for the first time from this area. Calicium parvum and C. trabinellum are new records for Turkey. The lichen diversity in three forests in different phytogeographical regions in the study area is discussed.


Phytotherapy Research | 2008

Determination of genotoxic, antigenotoxic and cytotoxic potential of the extract from lichen Cetraria aculeata (Schreb.) Fr. in vitro

Hülya Zeytinoğlu; Z. Incesu; B. Ayaz Tüylü; Ayşen Özdemir Türk; B. Barutca

Collaboration


Dive into the Ayşen Özdemir Türk's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge