Publications by authors named "Tamer Karayıldırım"

Microbial secondary metabolites, which play a pivotal role in struggling with infectious diseases, are the new source for controlling bacterial contaminations and possess a strong antimicrobial potential. The present study is designed to evaluate the and bactericidal activities of prodigiosin against . For this purpose, was used to produce prodigiosin.

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Chronic myelogenous leukemia (CML) is characterized by Philadelphia translocation arising from Bcr-Abl fusion gene, which encodes abnormal oncoprotein showing tyrosine kinase (TK) function. Certain mutations in kinase domain, off-target effects and resistance problems of current TK inhibitors require the discovery of novel Abl TK inhibitors. For this purpose, herein, we synthesized new gypsogenin derivatives (6a-l) and evaluated their anticancer effects towards CML cells along with healthy cell line and different leukemic cells.

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Silene species are known for their use in traditional medicine in treating several diseases. To the authors' knowledge there is no report on the chemical composition of S. odontopetala.

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The genus Scabiosa (Caprifoliaceae) is represented by 80 species, widely used as medicinal plants for their positive effects on human diseases. On the basis of the interesting biological activity shown by Scabiosa spp., the phytochemical investigation of Scabiosa sicula L.

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The clinical impact and accessibility of Tc tracers for cancer diagnosis would be greatly enhanced by the availability of a new, simple, and easy labeling process and radiopharmaceuticals. 5-Fluorouracil is an antitumor drug, which has played an important role for the treatment of breast carcinoma. In the present study, a new derivative of 5-Fluorouracil was synthesized as (1-[{1'-(1''-deoxy-2'',3'':4'',5''-di-O-isopropylidene-β-D-fructopyranose-1''-yl)-1'H-1',2', 3'-triazol-4'-yl}methyl]-5-fluorouracil) (E) and radiolabeled with Tc.

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A new steroidal glycoside, 3- O-β-d-glucopyranosyl-3β,25-dihydroxy-5β-cholest-7-en-6-one 25- O-β-d-glucopyranoside (1), together with six known steroidal derivatives (2-7), one cerebroside (8) and one flavonoid (9) were isolated from Silene montbretiana Boiss (Caryophyllaceae), a perennial herb growing mainly in the Middle and East Anatolia, Azerbaijan, Iran, and Turkey. Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS analyses. The cytotoxicity against the cancer A549 (human alveolar basal carcinoma) and Hela (human epitheloid cervix carcinoma) cell lines has been evaluated.

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With the aim to create a library of compounds with potential bioactivities by combining special characteristics of two important groups such as nucleobases and carbohydrates, twenty 1,4-disubstituted-triazole nucleosides were synthesized in good yields (80-94%) using the copper catalyzed 'Click' reaction between azido-modified pento- or hexopyranoses and alkyne-bearing pyrimidine or purine nucleobases. Structural elucidation was made with the assistance of spectroscopic techniques such as FTIR, 1D-, 2D-NMR, and ESI-TOFMS. All the synthesized triazole nucleosides were evaluated for their cytotoxic activity against three human cancer cell lines (MDA-MB-231, Hep3B, PC-3) by using the MTT assay.

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A series of gypsogenin (1) derivatives (1a-i) was synthesized in good yields, and the derivatives' structures were established using UV, IR, (1)H NMR, (13)C NMR, and LCMS spectroscopic data. Among the tested compounds, 1a, 1b, 1d, 1e, and gypsogenin (1) showed antimicrobial activities against Bacillus subtilis and Bacillus thrungiensis, with inhibition zones of 10-14 mm. In addition, compounds 1b, 1d, and 1e showed antimicrobial activities against Bacillus cereus, with inhibition zones of 9-14 mm.

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Three new oleanane-type glycosides, 1-3, were isolated from the whole plant of Tremastelma palaestinum (L.) Janchen, along with eight known triterpene glycosides. The structures of the new compounds were established as 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (2), and 3-O-[α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]oleanolic acid 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (3) by using 1D- and 2D-NMR techniques and mass spectrometry.

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As a part of our ongoing research for bioactive compounds from Turkish Astragalus species, the investigation of Astragalus tauricolus has been carried out. An approach based on HPLC-ESIMS(n) experiments has been used to profile the triterpene glycosides occurring in the butanol extract of the whole plant. On the basis of the results of the online screening by HPLC-ESIMS(n), 22 oleanane-type triterpene glycosides, including ten compounds never reported before, were isolated, and their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis.

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Six new cycloartane-type (1- 6) and four new oleanane-type (7- 10) triterpene glycosides were isolated from Astragalus angustifolius Lam., together with five known triterpene glycosides. Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis.

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Five triterpene saponins never reported before, hederifoliosides A-E, and four known triterpene saponins were isolated from the tubers of Cyclamen hederifolium. The structures of hederifoliosides A-E were determined as 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-[β-D-glucopyranosyl-(1 → 6)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,30-trihydroxyolean-12-en-28-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,28,30-tetrahydroxyolean-12-en 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. The cytotoxic activity of the isolated compounds was evaluated against a small panel of cancer cell lines including Hela, H-446, HT-29, and U937.

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Eighteen derivatives of egonol (A-R) were synthesized and evaluated for their antimicrobial activities against Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231 and Escherichia coli ATCC 8739 microorganisms comparing with egonol. The obtained data reported that compound B exhibited improved activities against all tested bacteria than egonol, others have shown different range of activities.

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The synthesis of new α,β-unsaturated furanuronic acid derivatives of α-gluco-, β-gluco- and β-manno-chloraloses via a convenient one pot procedure using the Knoevenagel-Doebner reaction approach are described. The dialdofuranose derivatives were reacted with malonic acid under Knoevenagel-Doebner reaction conditions and (E)-α,β-unsaturated furanuronic acid derivatives were obtained.

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The antimicrobial activities and some chemical properties of the traditional Turkish food called mesir paste were studied. Results of chemical analysis for moisture and volatiles, water-insoluble components, refractive index, soluble solids content, raw fiber, invert sugar, total ash, 5-hydroxymethylfurfural, acidity, and pH were calculated as 17.06%, 2.

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Three known iridoid glycosides, antirrhide (1), antirrhinoside (2), and 5-O-beta-allosylantirrhinoside (3), and two known flavone glycosides, linariin (4"'-O-acetylpectolinarin) (4) and linarin (acacetin-7-O-beta-D-rutinoside) (5) were isolated from Linaria kurdica Boiss & Hohen. subsp. eriocalyx.

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A new secondary metabolite, pterocephaline, along with the known cantleyoside, 7alpha-morroniside, 3beta,5alpha-tetrahydrodesoxycordifoline lactam, 5S-5-carboxyvincoside, sweroside, and loganin have been isolated from the aerial parts of P. pinardii (Dipsacaceae). Moreover, cantleyoside-methyl-hemiacetal and cantleyoside-dimethyl-acetal were obtained as seco-iridoid artifacts.

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