Semiha Yenigun

Dr. Semiha Yenigun

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

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

Representative Publications

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2 July 2023 in Journal of Biomolecular Structure and Dynamics
Verified
Journal Article
Closed access
SYSemiha Yenigun
Semiha Yenigun
YBYunus Başar
Yunus Başar
YİYaşar İpek
Yaşar İpek
LBLütfi Behçet
Lütfi Behçet
TOTevfik Ozen
Tevfik Ozen
ibrahim demirtasibrahim demirtas
ibrahim demirtas
Ursolic acid (UA), which has many biological properties such as anti-cancer, anti-inflammatory and antioxidant, and regulates some pharmacological processes, has been isolated from the flowers, leaves, berries and fruits of many plant species. In this work, UA was purified from the methanol-chloroform crude extract of Nepeta species (N. aristata, N. baytopii, N. italica, N. trachonitica, N. stenantha) using a silica gel column with chloroform or ethyl acetate solvents via bioactivity-guided isolation. The most active sub-fractions were determined under bioactivities using antioxidant and DNA protection activities and enzyme inhibitions. UA was purified from these fractions and its structure was elucidated by NMR spectroscopy techniques. The highest amount of UA was found in N. stenantha (8.53 mg UA/g), while the lowest amount of UA was found in N. trachonitica (1.92 mg UA/g). The bioactivities of UA were evaluated with antioxidant and DNA protection activities, enzyme inhibitions, kinetics and interactions. The inhibition values (IC50) of α-amylase, α-glucosidase, urease, CA, tyrosinase, lipase, AChE, and BChE were determined between 5.08 and 181.96 µM. In contrast, Ki values of enzyme inhibition kinetics were observed between 0.04 and 0.20 mM. In addition, Ki values of these enzymes for enzyme-UA interactions were calculated as 0.38, 0.86, 0.45, 1.01, 0.23, 0.41, 0.01 and 2.24 µM, respectively. It is supported that UA can be widely used as a good antioxidant against oxidative damage, an effective DNA protector against genetic diseases, and a suitable inhibitor for metabolizing enzymes.Communicated by Ramaswamy H. Sarma.

24 August 2023 in Journal of Biomolecular Structure and Dynamics
Verified
Journal Article
Closed access
YBYunus Başar
Yunus Başar
SYSemiha Yenigun
Semiha Yenigun
YİYaşar İpek
Yaşar İpek
LBLütfi Behçet
Lütfi Behçet
FGFatih Gül
Fatih Gül
ibrahim demirtasibrahim demirtas
ibrahim demirtas
1,5,9-epideoxyloganic acid (ELA) was isolated from the aerial parts of endemic Nepeta aristata Boiss Et Kotschy Ex Boiss crude extract (methanol:chloroform) using silica gel (hexane, chloroform, ethyl acetate, and methanol) and sephadex LH-20 (65% methanol-35% chloroform) columns. Activity-guided isolation was performed on methanol sub-fractions with DNA protection and enzyme inhibitory activities, and then the ELA was purified by prep-HPLC. The ELA structure, bio-guided isolate, was determined via 1H NMR, 13C NMR, and MS spectrometry. ELA's enzyme inhibition and DNA protection activities were investigated and compared with standard drugs. The inhibition capacity of ELA against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), urease, carbonic anhydrase (CA), α-glucosidase, α-amylase, lipase, and tyrosinase enzymes was evaluated by kinetic and molecular docking results. The ELA displayed the best inhibitory activity on AChE, BChE, α-glucosidase, urease, α-amylase, and tyrosinase with IC50 values of 2.53 ± 0.27, 3.75 ± 0.11, 3.98 ± 0.07, 4.40 ± 0.01, 6.43 ± 0.54 and 7.39 ± 0.00 µg/mL, respectively. ELA acted as a competitive inhibitor against BChE and α-glucosidase and a non-competitive inhibitor against AChE. The ELA's binding affinity values on AChE, BChE, and α-glucosidase were -7.70, -8.50, and -8.30 kcal/mol, respectively. DNA protection activity of the ELA molecule was determined as 57.53% for form I and 53.57% for form II. In conclusion, the inhibitory activity of ELA demonstrated its effectiveness in terms of its suitability in the pharmaceutical industry.Communicated by Ramaswamy H. Sarma.

6 April 2023 in Journal of Biomolecular Structure and Dynamics
Verified
Journal Article
Closed access
SYSemiha Yenigun
Semiha Yenigun
YIYasar Ipek
Yasar Ipek
SMSarmad Marah
Sarmad Marah
ibrahim demirtasibrahim demirtas
ibrahim demirtas
TOTevfik Ozen
Tevfik Ozen
Parietin was isolated from Xanthoria parietina (L.) Th. Fr.’ (methanol:chloroform) extract, using a silica column. 13 C NMR and 1H NMR were used to confirm the structure of the isolated parietin. For the first time, parietin was investigated for its antioxidant, antibacterial and DNA protective activities. Molecular docking was carried out to determine the binding affinity and interactions between the enzymes and our molecule. Inhibition and kinetic mechanism studies for the action of the enzymes were performed too. Parietin exhibited high metal chelating activity. The MIC values of parietin were sufficient to inhibit different bacterial strains; E. coli, P. aeruginosa, K. pneumoniae and S. aureus. Molecular docking applications exhibited that acetylcholinesterase (AChE), butyrylcholinesterase (BChE), lipase, and tyrosinase have high potential for binding with the parietin. Especially, the parietin’s highest binding affinity was recorded with AChE and tyrosinase. These results were confirmed by the inhibition and kinetics results, where, parietin observed a potent inhibition with an IC50 values between 0.013-0.003 µM. Moreover, parietin acts’ as a non-competitive inhibitor against AChE, BChE, and lipase, and as a competitive inhibitor against tyrosinase with a high rate of inhibition stability. The promising biological properties of parietin revealed its effectiveness in terms of suitability in the food and pharmaceutical industries. Communicated by Ramaswamy H. Sarma


5 June 2024 in International Journal of Chemistry and Technology
Verified
Journal Article
Open access
YBYunus Başar
Yunus Başar
SYSemiha Yenigun
Semiha Yenigun
FGFatih Gül
Fatih Gül
TOTevfik Ozen
Tevfik Ozen
IDİbrahim Demi̇rtas
İbrahim Demi̇rtas
STSüleyman Temel
Süleyman Temel
Atriplex nitens Schkuhr (ANS), which grows naturally in arid and semi-arid regions of the world, is highly resistant to drought and salty environments and is used as food and animal feed. This study first performed phytochemical analysis and antioxidant and urease inhibition activities on the obtained methanol crude extract of ANS. The catechin and isoquercitrin were detected as the main compounds according to LC-MS/MS results. Oleic acid methyl ester (31.71%), palmitic acid methyl ester (25.87%), linoleic acid methyl ester (19.61%), and nonacosane (16.81%) were detected in GC-MS/MS analysis of extract. Posphomolybdenum reducing, DPPH˙ scavenging, and urease inhibition activities were found effective at 67.27±23.83, 7.85±0.44 and 6.58±0.48 µg/mL, respectively, of ANS extract. In this investigation, the biological activity and chemical composition of the ANS extract were initially examined. Molecular docking and ADMET prediction were performed on this plant's two most abundant components. It was found that the interaction with urease of isoquercitrin (MolDock score-121.42, binding affinity -8.60, and binding constant 0.62 µM) with urease determined a higher than. These two components have a negligible potential for toxicity. The Boiled Egg plot indicates a significant GIa for catechin. However, isoquercitrin does not exhibit BBB or GLa permeability. It was determined that the main component isoquercitrine may be effective against gastric diseases, and it was supported that it was not observed in the BBB and GLa systems.

19 October 2017 in Combinatorial Chemistry & High Throughput Screening
Verified
Journal Article
Closed access
TOTevfik Ozen
Tevfik Ozen
SYSemiha Yenigun
Semiha Yenigun
MAMuhammed Altun
Muhammed Altun
IDIbrahim Demirtas
Ibrahim Demirtas
Aim and objective: Due to the common ethnopharmacological used or scientifically examined biochemical properties, Elaeagnaceae family, Elaeagnus umbellata Thunb (EU, Güz yemişi) was worth investigating. Materials and methods: In this investigation, we revealed antioxidant, antiproliferative and enzyme inhibition activities of the water, methanol, ethanol, acetone, ethyl acetate and hexane extracts of EU as well as the contents of their phenolic, flavonoid, anthocyanin, ascorbic acid, lycopene and β-carotene. The antioxidant activity was screened by total antioxidant (phosphomolybdenum assay), inhibition of linoleic acid peroxidation, reducing power, deoxyribose assay, H2O2 scavenging and metal chelating activities of the samples were tested in vitro. Additionally, the scavenging activities of the extracts were determined against 1,1-diphenyl-2-picrylhydrazyl (DPPH˙), 2,2-azino-bis(3-ethylbenzothiazloine-6- sulfonicacid (ABTS˙+), superoxide anion and peroxide radicals. The samples were determined for their inhibitory activities against urease, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro, antiproliferative activities of six different extracts were tested using the xCELLigence system against HeLa and HT29 cell lines. Results: The antioxidant activities of the extracts were found higher than standard antioxidants. The water extracts of fruit and leaf showed the best antioxidant activity. In inhibition assays of urease, AChE and BuChE, all extracts exhibited remarkable inhibition potential. Ethyl acetate extracts, especially, showed better inhibition capacity. It was found that the antioxidant activities of the extracts presented consistently with their chemical contents. The antiproliferative activities of leaf extracts were more effective than the fruit extracts. The chromatographic methods were applied to the different solvents to analyses phenolic secondery metabolites. It was found that fumaric acid, 4-hydroxybenzoic acid, rutin and quercetin-3-β-D-glucoside, neohesperidin, hesperidin determined to have higher contents all the extracts. Conclusion: EU can be suggested as a potential natural source of antioxidants appropriate for utilization in nutritional/pharmaceutical fields.