Mehmet Koca

Prof. Dr. Mehmet Koca


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 January 2023 in Applied Sciences
Verified
Journal Article
Open access
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EKEsen Sezen Karaoğlan
Esen Sezen Karaoğlan
HHHayrunisa Hanci
Hayrunisa Hanci
MKMehmet Koca
Mehmet Koca
CKCavit Kazaz
Cavit Kazaz
In this study, we aimed to isolate compounds from Stachys lavandulifolia (Lamiaceae) by chromatographic methods and perform tyrosinase, acetylcholinesterase, butyrylcholinesterase enzyme-inhibition and antimicrobial activity studies of these compounds by in vitro methods. In addition, a molecular docking study was planned for the molecule with the highest effect. Two flavone glycosides, apigenin-7-O-glucoside and luteolin-7-O-glucoside, were isolated from S. lavandulifolia. Both compounds were observed to be effective against Enterococcus faecalis, Klebsiella pneumoniae, and Staphylococcus aureus. The compounds showed weak tyrosinase and butyrylcholine esterase inhibition, while only luteolin-7-O-glucoside showed a more significant inhibitory effect against acetylcholinesterase (65 ± 2%). Therefore, molecular interactions between acetylcholinesterase and luteolin-7-O-glucoside were evaluated. In the docking study, it was observed that the molecule was bound to the enzyme with a low amount of free binding energy (Glide score: −8.31). As a result, the antibacterial effect of apigenin-7-O-glucoside and both antibacterial and acetylcholinesterase-inhibitory effects of luteolin-7-O-glucoside were determined.

17 February 2019 in Molecules
Verified
Journal Article
Open access
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SKSongül KARAKAYA
Songül KARAKAYA
MKMehmet Koca
Mehmet Koca
SYSerdar Volkan Yılmaz
Serdar Volkan Yılmaz
KYKadir Yıldırım
Kadir Yıldırım
NPNur Münevver Pınar
Nur Münevver Pınar
Oksana SytarOksana Sytar
Oksana Sytar
Coumarins and essential oils are the major components of the Apiaceae family and the Zosima genus. The present study reports anticholinesterase and antioxidant activities of extracts and essential oils from aerial parts, roots, flowers, fruits and coumarins—bergapten (1); imperatorin (2), pimpinellin (3) and umbelliferone (4)—isolated of the roots from Zosima absinthifolia. The investigation by light and scanning electron microscopy of the structures of secretory canals found different chemical compositions in the various types of secretory canals which present in the aerial parts, fruits and flowers. The canals, present in the aerial parts, are characterized by terpene hydrocarbons, while the secretory canals of roots, flowers and fruits include esters. Novel data of a comparative study on essential oils constituents of aerial parts, roots, flowers and fruits of Z. absinthfolia has been presented. The roots and fruits extract showed a high content of total phenolics and antioxidant activity. The GC-FID and GC-MS analysis revealed that the main components of the aerial parts, roots, flowers and fruits extracts were octanol (8.8%), octyl octanoate (7.6%), octyl acetate (7.3%); trans-pinocarvyl acetate (26.7%), β-pinene (8.9%); octyl acetate (19.9%), trans-p-menth-2-en-1-ol (4.6%); octyl acetate (81.6%), and (Z)-4-octenyl acetate (5.1%). The dichloromethane fraction of fruit and flower essential oil was characterized by the highest phenolics level and antioxidant activity. The dichloromethane fraction of fruit had the best inhibition against butyrylcholinesterase enzyme (82.27 ± 1.97%) which was higher then acetylcholinesterase inhibition (61.09 ± 4.46%) of umbelliferone. This study shows that the flowers and fruit of Z. absinthifolia can be a new potential resource of natural antioxidant and anticholinesterase compounds.

24 May 2018 in Medicinal Chemistry Research
Verified
Journal Article
Closed access
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SKSongül KARAKAYA
Songül KARAKAYA
MKMehmet Koca
Mehmet Koca
CKCeyda Sibel Kılıç
Ceyda Sibel Kılıç
MCMaksut Coskun
Maksut Coskun

30 December 2019 in Anales del Jardín Botánico de Madrid
Verified
Journal Article
Open access
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SKSongül KARAKAYA
Songül KARAKAYA
GEGulnur Eksi
Gulnur Eksi
MKMehmet Koca
Mehmet Koca
BDBetul Demirci
Betul Demirci
HKHaluk Çağlar Kaymak
Haluk Çağlar Kaymak
ÖAÖzkan Aksakal
Özkan Aksakal
Alzheimer’s disease is the main reason for dementia, which increases with age. Cholinesterase inhibition and antioxidant potentials of extracts and essential oils from bulbs of A. tuncelianum (Kollmann) Özhatay & al., an endemic species to Tunceli (easthern Turkey), were evaluated. The fraction extracted of ethyl acetate had the highest phenolics level, 1,1-diphenyl-2-picrylhydrazyl, and thiobarbituric acid antioxidant capacity. Also, the ethyl acetate fraction presented the highest acetylcholinesterase (15.98 ± 2.76%), and butyrylcholinesterase inhibition (47.33 ± 3.27%). Diallyl disulfide (49.8%), diallyl trisulfide (27.9%) and allyl methyl trisulfide (6.9%) were found to be the major components of essential oil. This paper shows that the ethyl acetate fraction of A. tuncelianum could be a potent source of antioxidant and anticholinesterase components.

24 June 2021 in Molecular Diversity
Verified
Journal Article
Closed access
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MKMehmet Koca
Mehmet Koca
SBSinan Bilginer
Sinan Bilginer

13 November 2020 in İstanbul Journal of Pharmacy
Verified
Journal Article
Open access
PDF file
EKEsen Sezen Karaoğlan
Esen Sezen Karaoğlan
MKMehmet Koca
Mehmet Koca
İstanbul Üniversitesi Yayın Projesi