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Öğe Anticancer, antioxidant, DFT calculations, and docking studies of some new peptide-indole conjugates(Acg Publications, 2024) Kucukbay, Hasan; Gonul, Zeynep; Kurucay, Ali; Ates, Burhan; Boulebd, Houssem; Kucukbay, F. ZehraIn this study, the structures of six new peptide-indole derivatives were elucidated through spectroscopic and analytical methods following their synthesis. In addition to their anticancer and antioxidant properties, density functional theory (DFT) calculations and docking studies were conducted for the compounds. According to the obtained results, compounds 1 and 3 were identified as the most active against the MCF-7 cell line, with IC50 values of 8.72 and 5.86 mu g/mL, respectively. Conversely, compounds 4 and 1 were found to be the most active against the A549 cell line, with IC50 values of 15.43 and 16.10 mu g/mL, respectively. When compared to standard antioxidants using both the DPPH and iron reduction power assays, the compounds did not exhibit significant antioxidant activity. The molecular geometry and electronic properties of the synthesized peptide-indole derivatives were investigated through theoretical calculations using the Density Functional Theory (DFT) method. Molecular docking studies were also conducted to investigate the binding modes of the synthesized compounds within the active sites of EGFR enzyme.Öğe CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITIES OF THE ESSENTIAL OILS OF Teucrium orientale var. orientale AND Teucrium orientale var. puberulens(Springer, 2011) Kucukbay, F. Zehra; Yildiz, Bayram; Kuyumcu, Ebru; Gunal, Selami[Abstract Not Available]Öğe Chemical composition and antimicrobial activity of essential oil of Achillea cretica L. (Asteraceae) from Turkey(Taylor & Francis Ltd, 2012) Kucukbay, F. Zehra; Kuyumcu, Ebru; Bilenler, Tuce; Yildiz, BayramHydrodistilled volatile oil from the aerial parts of Achillea cretica L. (Asteraceae) was analysed by a combination of GC and GC/MS. Seventy-six components were identified, constituting 86.4% of the oil. The main constituents of the essential oil were caryophylladienol-II (13.4%), beta-maaliene (6.1%), neo-intermedeol (6.0%), carvone (4.9%), spathulenol (4.5%), palmitic acid (3.3%) and selina-3,11-dien-6 alpha-ol (3.2%). The antimicrobial activity was evaluated by the broth-dilution method on nine microbial strains and showed to be quite strong against the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus. The antibacterial properties of A. cretica justify its use in traditional medicine for the treatment of wounds, contaminated through bacterial infections.Öğe Chemical Composition and Antimicrobial and Antioxidant Activities of three Turkish Thyme Essential Oils(Taylor & Francis Ltd, 2013) Kucukbay, F. Zehra; Kuyumcu, Ebru; Celen, Selma; Azaz, Ayse Dilek; Arabaci, Turan; Yildiz, BayramThe aim of present study was to compare the antioxidant and antimicrobial activities of three Thymus kotschyanus varieties on the basis of the chemical compositions of oils obtained by hydrodistillation. GC-MS analysis of the isolated essential oils from aerial parts of Thymus kotschyanus Boiss. & Hohen. var. eriophorus (Ronniger) Jalas, Thymus kotschyanus Boiss. & Hohen. var. kotschyanus and Thymus kotschyanus Boiss. & Hohen. var. glabrascens resulted in the identification of 55,, 34 and 57 constituents, respectively. The major components in the essential oils of T. kotschyanus Boiss. & Hohen. var. eriophorus (Ronniger) Jalas and T. kotschyanus Boiss. & Hohen. var. kotschyanus were described as geraniol (55.0-59.1 %) and geranyl acetate (27.1-28.8 %). The oil of T. kotschyanus Boiss. & Hohen. var. glabrascens is characterized by the high monoterpene fraction (86.5 %) and especially by the presence of carvacrol (57.2 %) and its precursor p-cymene (11.0 %). The essential oils were studied in vitro for antimicrobial activity (as inhibition zone and MIC) against fourteen bacteria strains using agar disc diffusion and broth micro-dilution methods. The oils exhibited moderate zone of inhibitions against bacteria when compared to standard antibiotics ketoconazol and chloramphenicol used as controls. The samples were subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH). When compared with the antioxidative potentials of the standard compound used in this study (BHA), essential oils of the T. kotschyanus varieties studied exerted remarkable antioxidant activity.Öğe Chemical Composition of the Essential Oils of Three Thymus Taxa from Turkey with Antimicrobial and Antioxidant Activities(Acg Publications, 2014) Kucukbay, F. Zehra; Kuyumcu, Ebru; Celen, Selma; Azaz, Ayse Dilek; Arabaci, TuranGC-MS analysis of the essential oils from aerial parts of Thymus migricus Klokov & Des.-Shost, Thymus fallax Fisch. & Mey. and Thymus pubescens Boiss. & Kotschy ex Celak var. pubescens resulted in the identification of 26, 35 and 53 constituents, respectively. The major components in the essential oil of T. migricus were found to be alpha-terpineol (30.6%), thymol (20.7%) and alpha-terpinyl acetate (14.9%) while in the essentiol oil of T. fallax cis-carveol (29.6%) and alpha-terpineol (10.8%). Carvacrol was a dominant compound with a percentage 66.1% of the essential oil of T. pubescens var. pubescens. The data obtained indicate that the essential oils of Thymus species generally exhibit some bacteriostatic activity. The antioxidant activity of the tested essential oils were found to be slightly lower than butylatedhydroxyanisole (BHA).Öğe Determination of Elements by Atomic Absorption Spectrometry in Medicinal Plants Employed to Alleviate Common Cold Symptoms(Office Spectroscopy & Spectral Analysis, 2014) Kucukbay, F. Zehra; Kuyumcu, EbruEleven important medicinal plants generally used by the people of Turkey for the treatment of common cold have been studied for their mineral contents. Eleven minor and major elements (essential, non-essential and toxic) were identified in the Asplenium adiantum-nigrum L., Althaea of ficinalis L., Verbascum Phlomoides L., Euphorbia chamaesyce L., Zizyphus jujube Miller, Peganum harmala L., Arum dioscoridis Sm., Sambucus nigra L., Piper longum L., Tussilago far fara L. and Elettaria cardamomum Maton by employing flame atomic absorption and emission spectrometry and electro-thermal atomic absorption spectrometry. Microwave digestion procedure for total concentration was applied under optimized conditions for dissolution of medicinal plants. Plant based biological certified reference materials (CRMs) served as standards for quantification. These elements are found to be present in varying concentrations in the studied plants. The baseline data presented in this work can be used in understanding the role of essential, non-essential and toxic elements in nutritive, preventive and therapeutic properties of medicinal plants.Öğe Determination of Minerals and Trace Elements in Soils and The Relation with its Concentrations in Sugar Beets(Asian Journal Of Chemistry, 2010) Kucukbay, F. Zehra; Kuyumcu, Ebru; Karaca, Idil; Ozdemir, DurmusTwelve sugar beets and corresponding soil samples from the plantation near Malatya. Turkey were analyzed for mineral and trace element contents Thirteen metals (Al, Ca. Cd, Cu. Fe. K. Mg, Mn. Na, Ni, Pb, Sc and Zn) were selected and analyzed quantitatively by FAAS/FAES and ETAAS. Principal component analysis and hierarchical cluster analysis were used to explore samples based on the element contents. The principal component analysis analysis of sugar beet samples yielded five principal components which were able to explain about 84% of the total variance in the data set. The number of principal components that are higher than one was four for the soil samples and were able to explain 83% of total variance Hierarchical cluster analysis of sugar beet samples and corresponding soil samples resulted in two main clusters based on the geographic regions of the samples In terms of the elements being analyzed, the hierarchical cluster analysis method resulted in 3-4 clusters of the elements in both sugar beet and soil samplesÖğe Essential oil chemical composition, antimicrobial, anticancer, and antioxidant effects of Thymus convolutus Klokov in Turkey(Walter De Gruyter Gmbh, 2021) Yuceturk, Selma Celen; Turkoglu, Sumeyye Aydogan; Kockar, Feray; Kucukbay, F. Zehra; Azaz, A. DilekIn this study, the chemical composition, antimicrobial, antioxidant, and anticancer effects of Thymus convolutus Klokov oil and its main compound camphor were investigated. The oil was isolated from T. convolutus using hydrodistillation method, analyzed by gas chromatography/mass spectrometry (GC-MS), and 66 compounds were identified. The main component was determined as camphor at 16.6%. The antioxidant properties were identified with the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical-scavenging method and, 33.39 +/- 0.25% DPPH was scavenging in 1000 mu g/mL of essential oil. The strong antimicrobial activity was observed against Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, and Pseudomonas aeruginosa with MIC values of 125 mu g/mL. Aspergillus flavus was more sensitive (28%) against T. convolutus essential oil than other fungi. The cytotoxic effect of oil was analyzed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Camphor was effective on human hepatoma cells (Hep3B) at concentrations of 1 mg/mL, 500, 250, and 125 mu g/mL, while essential oil of T. convolutus was found to be effective at concentrations of 250 and 125 mu g/mL. A reduction in cell proliferation was observed in colon carcinoma cells (HT-29) treated with 500 mu g/mLcamphor for 48 h. No statistically significant effect was found in Umbilical Vein Endothelial Cells (HUVEC) treated with essential oil and camphor.Öğe Essential Oil Composition from the Aerial Parts of Ajuga orientalis L. Growing in Turkey(Asian Journal Of Chemistry, 2013) Kucukbay, F. Zehra; Kuyumcu, Ebru; Yildiz, BayramThe essential oil obtained from the aerial parts of Ajuga orientalis L. (Lamiaceae) was analyzed by using GC and GC-MS. Thirty compounds representing 95.4 % of the oil were identified. The main compounds were phytol (36.7 %), n-hexadecanoic acid (14.2 %) and dodecanoic acid (12.2 %).Öğe Essential Oil Composition of Thymus eriocalyx (Ronniger) Jalas from Turkey(Asian Journal Of Chemistry, 2010) Kucukbay, F. Zehra; Kuyumcu, EbruHydrodistilled volatile oil from the aerial parts of Thymus eriocalyx (Ronniger) Jalas was analyzed by a combination of GC and GC-MS Seventy compounds were identified, representing 98.54 % of the oil The major components were found to be thymol (47 79 %). beta-caryophyllene (11.98 %), 1,8-cineole (9 88 %), borneol (3 88 %), p-cymene (3 02 %), carvacrol methyl ether (2 99 %), gamma-terpinene (2 97 %) and germacrene D (2 83 %)Öğe THE ESSENTIAL OIL OF Achillea boissieri(Springer, 2010) Kucukbay, F. Zehra; Kuyumcu, E.; Arabaci, T.[Abstract Not Available]Öğe Kumquat fruit and leaves extracted with different solvents: phenolic content and antioxidant activity(Kemerovo State Univ, 2022) Buyukkormaz, Cagri; Kucukbay, F. ZehraIntroduction. Kumquat is a good source of vitamin C, as well as phenolic and flavonoid substances. In this study, we used various solvents to obtain extracts from fresh and lyophilized dried fruits and leaves of kumquat plant, as well as six mutants, to compare their total phenolic and flavonoid contents and antioxidant activities. Study objects and methods. The total phenolic and flavonoid content was determined by the Folin-Ciocalteu method and the colorimetric method, respectively. The antioxidant capacities of the extracts were determined by commonly used antioxidant tests, such as the DPPH radical scavenging activity, reducing power, and metal chelating activity. Results and discussion. The total phenolic content of the extracts was in the range of 3705-86 329 mg GAE/g extract. The total amount of flavonoid substance ranged from 5556 to 632 222 mg QUE/g extract. The highest free radical scavenging activity was observed in the kumquat leaves. We also found that the activity of dried fruit was lower than that of fresh fruit. According to our results, the differences in the phenolic contents of the studied plants affected their antioxidant properties. We determined that the extracts with a high phenolic content showed high antioxidant activity. No significant difference was detected between the rootstock kumquat type and its mutants. Finally, we found no chelating activity in the extracts obtained from fresh and lyophilized dried fruits. Conclusion. Kumquat fruit and its leaves can be considered as functional foods due to phenolic compounds, which are able to neutralize free radicals.Öğe Macrocyclic peptidomimetics with antimicrobial activity: synthesis, bioassay, and molecular modeling studies(Royal Soc Chemistry, 2015) Ibrahim, Mohamed A.; Panda, Siva S.; Oliferenko, Alexander A.; Oliferenko, Polina V.; Girgis, Adel S.; Elagawany, Mohamed; Kucukbay, F. ZehraNovel, cyclic peptidomimetics were synthesized by facile acylation reactions using benzotriazole chemistry. Microbiological testing of the synthesized compounds revealed an exceptionally high activity against Candida albicans with a minimum inhibitory concentration (MIC) two orders of magnitude lower than the MIC of the antifungal reference drug amphotericin B. A strikingly high activity was also observed against three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus vulgaris), two of which are known human pathogens. Thus the discovered chemotype is a potential poly-pharmacological agent. The toxicity against mammalian tumor cells was found to be low, as demonstrated in five different human cell lines (HeLa, cervical; PC-3, prostate; MCF-7, breast; HepG2, liver; and HCT-116, colon). The internal consistency of the experimental data was studied using 3D-pharmacophore and 2D-QSAR.Öğe Mineral Composition of Some Fruit, Fruit Tissue and Leafy Vegetables Consumed for Medicinal Purpose in Malatya, Turkey(Asian Journal Of Chemistry, 2014) Kucukbay, F. Zehra; Tosun, EmirThis study investigates the presence of K, Mg, Al, Fe, Mn, Zn, Cu Se Pb and Cd in the fruit, fruit tissues and leafy vegetable samples frequently consumed for therapeutic purpose in Malatya, located in the region of Eastern Anatolia in Turkey. Microwave digestion procedure for total concentration was applied under optimized conditions for dissolution of plant samples. Element concentrations in plant samples were determined by atomic absorption spectroscopy. The accuracy and precision were verified against leaves certified reference material. The results of this study showed that the average concentrations detected ranged from 114 to 4754.2 mg 100 g(-1), 10 to 637.8 mg 100 g(-1), 1.45 to 92.83 mg 100 g(-1), 0.30 to 61.54 mg 100 g(-1), 0.034 to 20.83 mg 100 g(-1), 0.06 to 6.26 mg 100 g(-1), 0.05 to 1.84 mg 100 g(-1), 8.91 to 351.55 mu g 100 g(-1), 0.60 to 56.10 mu g 100 g(-1) and 0.10 to 6.48 mu g 100 g(-1) for K, Mg, Al, Fe, Mn, Zn, Cu, Pb, Se, Cd, respectively. Most of studied species contains the trace below the permissible limit (FAO/WHO 1984). The study revealed that investigated plant samples are good source of K, Mg, Fe, Mn, Zn, Cu and Se. However, some plant samples such as mint, basil, walnut and quince contained high levels of lead.Öğe Preparation, carbonic anhydrase enzyme inhibition and antioxidant activity of novel 7-amino-3,4-dihydroquinolin-2(1H)-one derivatives incorporating mono or dipeptide moiety(Taylor & Francis Ltd, 2020) Kucukbay, Hasan; Gonul, Zeynep; Kucukbay, F. Zehra; Angeli, Andrea; Bartolucci, Gianluca; Supuran, Claudiu T.New dipeptide-dihydroquinolinone derivatives were successfully synthesised by benzotriazole mediated nucleophilic acyl substitution reaction and their structures were elucidated by spectroscopic and analytic techniques. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was determined against four human (h) isoforms, hCA I, hCA II, hCA IX and hCA XII. While all compounds showed moderate to good in vitro CA inhibitory properties against hCA IX and hCA XII with inhibition constants in the micromolar level (37.7-86.8 and 2.0-8.6 mu M, respectively), they did not show inhibitory activity against hCA I and hCA II up to 100 mu M concentration. The antioxidant capacity of the peptide-dihydroquinolinone conjugates was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. Most of the synthesised compounds showed low antioxidant activities compared to the control antioxidant compounds BHA and alpha-tocopherol.Öğe Simultaneous Determination of Water and Fat-Soluble Vitamins in Pekmez Samples by High Performance Liquid Chromatography Coupled with Diode Array Detection(Asian Journal Of Chemistry, 2010) Kucukbay, F. Zehra; Karaca, IdilIn the present work, a RP-HPLC procedure has been applied for the determination of water-soluble vitamins (riboflavin. nicotinamide. pantothenic acid. pyridoxine hydrochloride. pyridoxal. folic acid, ascorbic acid) and tat-soluble vitamins (trans-retinol. alpha-tocopherol) in pekmez samples. a tradional Turkish concentrate fruit food The sample treatment proposed consists of a solid-phase extraction with Sep-Pak C(18) cartridges that allow the seperation of fat-soluble vitamins, which were retained on the sorbent, from water-soluble vitamins. After isolation of the two fractions, the water-soluble vitamins were analyzed by HPLC on an ACE 5 C(18) (250 x 4.6 mm, 5 mu m) analytical column using 0.1 mol L(-1) KH(2)PO(4) (pH 7 0)-CH(3)OH as mobile phase The chromatographic analysis of the fat-soluble vitamins was earned out after their sequential elution with CH(3)OH-CCl(4) from C(18) sorbent. on the above column. Afterwards. the fat-soluble vitamins were analyzed on an ACE 5 C(18) analytical with isocratic mobile phase consisting of CH(3)OH-CH(3)CN at a flow-rate of 2 mL min(-1). Identification of compounds was achieved by comparing their retention times and UV spectra with those of standards stored in a data bank The accuracy of the method was tested obtaining an average recovery ranging between 91 and 110%.Öğe Synthesis and carbonic anhydrase I, II, IV and XII inhibitory properties of N-protected amino acid - sulfonamide conjugates(Taylor & Francis Ltd, 2016) Kucukbay, F. Zehra; Kucukbay, Hasan; Tanc, Muhammet; Supuran, Claudiu T.N-protected amino acids (Gly, Ala and Phe protected with Boc and Z groups) were reacted with sulfonamide derivatives, leading to the corresponding N-protected amino acid-sulfonamide conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA IV and hCA XII. Among them, hCA II, IV and XII are antiglaucoma drug targets, being involved in aqueous humor secretion within the eye. Low nanomolar inhibition was measured against all four isoforms with the 20 reported sulfonamides, but no selective inhibitory profiles, except for some CA XII-selective derivatives, were observed. hCA I, II and XII were generally better inhibited by sulfonamides incorporating longer scaffolds and Gly/Ala, whereas the best hCA IV inhibitors were homosulfanilamide derivatives, incorporating Phe moieties. The amino acid-sulfonamide conjugates show good water solubility and effective hCA II, IV and XII inhibition, and may be considered as interesting candidates for antiglaucoma studies.Öğe Synthesis and carbonic anhydrase inhibitory properties of amino acid - coumarin/quinolinone conjugates incorporating glycine, alanine and phenylalanine moieties(Taylor & Francis Ltd, 2016) Kucukbay, F. Zehra; Kucukbay, Hasan; Tanc, Muhammet; Supuran, Claudiu T.N-Protected amino acids (Gly, Ala and Phe) were reacted with amino substituted coumarin and quinolinone derivatives, leading to the corresponding N-protected amino acid-coumarin/quinolinone conjugates. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against various human (h) isoforms, such as hCA I, hCA II, hCA IV and hCA XII. The quinolinone conjugates were inactive as enzyme inhibitors, whereas the coumarins were ineffective hCA I/II inhibitors (K(I)s>50 mu M) but were submicromolar hCA IV and XII inhibitors, with inhibition constants ranging between 92 nM and 1.19 mu M for hCA IV, and between 0.11 and 0.79 mu M for hCA XII. These coumarin derivatives, as many others reported earlier, thus show an interesting selective inhibitory profile for the membrane-bound over the cytosolic CA isoforms.Öğe Synthesis and carbonic anhydrase inhibitory properties of novel 4-(2-aminoethyl)benzenesulfonamide-dipeptide conjugates(Academic Press Inc Elsevier Science, 2019) Kucukbay, Hasan; Bugday, Nesrin; Kucukbay, F. Zehra; Berrino, Emanuela; Bartolucci, Gianluca; Del Prete, Sonia; Capasso, ClementeThirty novel sulfonamide derivatives incorporating dipeptide were synthesized by facile acylation through benzotriazole mediated reactions and their structures were identified by H-1 NMR, C-13 NMR, MS and FT-IR spectroscopic techniques and elemental analysis. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity of the new compounds was assessed against four human (h) isoforms, hCA I, hCA II, hCA IV and hCA XII. Most of the synthesized compounds showed excellent in vitro carbonic anhydrase inhibitory properties comparable to those of the clinically used drug acetazolamide (AAZ). The new unprotected dipeptide-sulfonamide conjugates showed very effective inhibitory activity, in the low nanomolar range against II and XII, being less effective as hCA I and IV inhibitors. Four of the thirty compounds also showed strong inhibitory activity against hCA XII compared to AAZ.Öğe Synthesis and Evaluation of Novel Benzimidazole Conjugates Incorporating Amino Acids and Dipeptide Moieties(Bentham Science Publ Ltd, 2017) Bugday, Nesrin; Kucukbay, F. Zehra; Apohan, Elif; Kucukbay, Hasan; Serindag, Ayfer; Yesilada, OzferBackground: Amino acids, short peptide sequences and benzimidazole derivatives play an increasingly important role as therapeutics in areas including antibacterial, antifungal, antiviral, anti-inflammatory, antiparasitic, antibiofilm, antidiabetic, and anticancer. Methods: Some novel amino acids and glycine-glycine dipeptide benzimidazole conjugates were synthesized by facile acylation reactions through DCC mediated reactions and their structures were identified by H-1-NMR, C-13-NMR and FT-IR spectroscopic techniques and elemental analysis. In vitro antimicrobial activities of some compounds against Gram positive (Staphylococcus aureus and Enterobacter faceium NJ-1) and Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and yeasts (Candida albicans and Candida tropicalis) were determined by MIC method. Their antioxidant activities were also detected by DPPH method. Results: Sixteen novel benzimidazole conjugates incorporating glycine, alanine, phenylalanine, cysteine and glycine-glycine dipeptide were synthesized and their structures were identified by spectroscopic techniques and elemental analysis. All of the compounds tested showed in vitro antimicrobial and antioxidant activities. Conclusion: Sixteen novel benzimidazole amino acid/dipeptide conjugates were synthesized using DCC mediated one step reaction in moderate yield and high purity, under mild reaction conditions, with full retention of the original chirality. Amino acid or dipeptide substitutions at position 1 of the benzimidazoles were synthesized first time in this work. The results have indicated that the newly synthesized compounds possess low to moderate antimicrobial and antioxidant activities.