Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 16Citation - Scopus: 17Antiproliferative Activity of (r)-4 '-methylklavuzon on Hepatocellular Carcinoma Cells and Epcam(+)/Cd133(+) Cancer Stem Cells Via Sirt1 and Exportin-1 (crm1) Inhibition(Elsevier Ltd., 2019) Delman, Murat; Avcı, Sanem Tercan; Akçok, İsmail; Kanbur, Tuğçe; Erdal, Esra; Çağır, AliCytotoxic effects of (R)-4'-methylklavuzon were investigated on hepatocellular carcinoma cells (HuH-7 and HepG2) and HuH-7 EpCAM(+)/CD133(+) cancer stem cells. IC50 of (R)-4'-methylklavuzon was found as 1.25 mu M for HuH-7 parental cells while it was found as 2.50 mu M for HuH-7 EpCAM(+)/CD133(+) cancer stem cells. (R)-4'-methylklavuzon tended to show more efficient in vitro cytotoxicity with its lower IC50 values on hepatocellular carcinoma cell lines compared to its lead molecule, goniothalamin and FDA-approved drugs, sorafenib and regorafenib. Cell-based Sirtuin/HDAC enzyme activity measurements revealed that endogenous Sirtuin/HDAC enzymes were reduced by 40% compared to control. SIRT1 protein levels were upregulated indicating triggered DNA repair mechanism. p53 was overexpressed in HepG2 cells. (R)-4'methylklavuzon inhibited CRM1 protein providing increased retention of p53 and RIOK2 protein in the nucleus. HuH-7 parental and EpCAM(+)/CD133(+) cancer stem cell spheroids lost intact morphology. 3D HepG2 spheroid viabilities were decreased in a correlation with upregulation in p53 protein levels. (C) 2019 Elsevier Masson SAS. All rights reserved.Article Citation - WoS: 44Citation - Scopus: 53Smart Phone Assisted Detection and Quantification of Cyanide in Drinking Water by Paper Based Sensing Platform(Elsevier Ltd., 2017) İncel, Anıl; Akın, Osman; Çağır, Ali; Yıldız, Ümit Hakan; Demir, Mustafa MuammerAn organometallic dye, europium tetrakis dibenzoylmethide triethylammonium (EuD4TEA) and gold nanoparticles (Au NPs) impregnated paper based sensor platform have been utilized for development of fluorescence turn-on cyanide assay in aqueous media. The ordinary filter paper with 6 μ m pore size were employed as solid support that facilitates impregnation of EuD4TEA and gold nanoparticles and provides durability. Detection mechanism relying on two processes (i) dissolution of gold nanoparticles causing fluorescence recovery and (ii) ligand exchange of triethyl amine with CN group stimulating cyanide specific fluorescence enhancement. The paper platform exhibit naked eye distinguishable color transition upon CN− addition from 10−2 to 10−12 M. To standardize the methodology a homemade image processing algorithm has been developed that enabling calibration of color change and quantify CN− concentration. The described algorithm is applicable to Android smart phones and facilitate transforming these devices into a quantitative cyanide detector. The overall methodology provides instrument free cyanide detection and therefore rapid control of water quality and safety at off-field conditions.Article Citation - WoS: 8Citation - Scopus: 8Synthesis and Topoisomerase I Inhibitory Properties of Klavuzon Derivatives(Elsevier Ltd., 2017) Akçok, İsmail; Mete, Derya; Şen, Ayhan; Kasaplar, Pınar; Korkmaz, Kemal S.; Çağır, AliKlavuzon is a naphthalen-1-yl substituted α,β-unsaturated δ-lactone derivative, and is one of the anti-proliferative members of this class of compounds. Asymmetric and racemic syntheses of novel α,β-unsaturated δ-lactone derivatives are important to investigate their potential for the treatment of cancer. In this study, asymmetric and racemic syntheses of heteroatom-substituted klavuzon derivatives are reported. The syntheses were completed by a well-known three-step procedure. Anti-proliferative activity of seven novel racemic klavuzon derivatives were reported against MCF-7, PC3, HCT116 p53+/+ and HCT116 p53−/− cancer cell lines. Topoisomerase I inhibitory properties of 5,6-dihydro-2H-pyran-2-one derivatives were also studied. © 2017 Elsevier Inc.Article Citation - WoS: 8Citation - Scopus: 9Crm1 Inhibitory and Antiproliferative Activities of Novel 4'-alkyl Substituted Klavuzon Derivatives(Elsevier Ltd., 2017) Kanbur, Tuğçe; Kara, Murat; Kutluer, Meltem; Şen, Ayhan; Delman, Murat; Alkan, Aylin; Otaş, Hasan Ozan; Akçok, İsmail; Çağır, AliKlavuzons are 6-(naphthalen-1-yl) substituted 5,6-dihydro-2H-pyran-2-one derivatives showing promising antiproliferative activities in variety of cancer cell lines. In this work, racemic syntheses of nine novel 4′-alkyl substituted klavuzon derivatives were completed in eight steps and anticancer properties of these compounds were evaluated. It is found that size of the substituent has dramatic effect over the potency and selectivity of the cytotoxic activity in cancerous and healthy pancreatic cell lines. The size of the substituent can also effect the CRM1 inhibitory properties of klavuzon derivatives. Strong cytotoxic activity and CRM1 inhibition can be observed only when a small substituent present at 4′-position of naphthalen-1-yl group. However, these substituents makes the molecule more cytotoxic in healthy pancreatic cells rather than cancerous pancreatic cells. Among the tested compounds 1,2,3,4-tetrahydrophenanthren-9-yl substituted lactone was the most cytotoxic compound and its antiproliferative activity was also tested in 3D spheroids generated from HuH-7 cell lines.Article Citation - WoS: 7Citation - Scopus: 7Cleavage of Ring a and Formation of an Unusual Nor-Triterpene Skeleton Via the Baeyer-Villiger Reaction(Elsevier Ltd., 2012) Tağ, Özgür; Çağır, Ali; Khan, Ikhlas A.; Bedir, ErdalWith the aim to generate a compound library for our biological screening studies, cycloastragenol was subjected to chemical transformation studies. The Baeyer-Villiger oxidation experiments provided an interesting 3,5-seco-4-nor-triterpene skeleton via ring opening followed by an unusual rearrangement. A new methodology is described for transforming triterpenoids into 3,5-seco-4-nor derivatives.Article Citation - WoS: 31Citation - Scopus: 346-Bicycloaryl Substituted (s)- and (r)-5,6 Asymmetric Synthesis, and Anti-Proliferative Properties(Elsevier Ltd., 2009) Kasaplar, Pınar; Yılmazer, Özgür; Çağır, Ali(R)-Goniothalamin, is a member of styryl lactones, possesses selective cytotoxicity against cancer cell lines. In this work, replacement of styryl substituent with 2-naphthyl and 3-quinoyl gave new analogues which may have less conformational changes compared to the lead compound. Anti-proliferative tests indicated that 2-naphthyl substituted (R)-5,6-dihydro-2H-pyran-2-one has slightly better cytotoxicity than (R)-goniothalamin. To clarify the effect of 2-naphthyl substituent additional aryl substituted (R)-5,6-dihydro-2H-pyran-2-ones have been synthesized enantioselectively and tested against PC-3 and MCF-7 cell lines.Article Citation - WoS: 19Citation - Scopus: 19Synthesis of Stilbene-Fused 2'-hydroxychalcones and Flavanones(Elsevier Ltd., 2010) Akçok, İsmail; Çağır, AliSynthesis of stilbene-fused chalcones and flavanones were successfully completed. Molecules were designed in a way to mimic the structural features of both "stilbene and chalcones" or "stilbene and flavanones" at the same time, and synthesized by three steps. Heck reactions of 3-bromobenzaldehyde with styrene derivatives gave corresponding (E)-stilbenes, which were reacted with acetophenones to furnish stilbene-fused 2′-hydroxychalcones under basic conditions. Finally, intramolecular cyclization reactions were performed to produce stilbene-fused flavanones. © 2010 Elsevier Inc.Article Citation - WoS: 8Citation - Scopus: 8Michael Acceptor Properties of 6-Bicycloaryl Substituted (r)-5,6(Elsevier Ltd., 2010) Kasaplar, Pınar; Çakmak, Özgür Yılmazer; Çağır, AliThe mechanism of action for α,β-unsaturated lactones can be explained by their Michael acceptor properties. They have the potential of being covalently binding inhibitors by accepting nucleophiles from target proteins. In this work, Michael addition reactions of ethanethiol with 6-bicycloaryl substituted 5,6-dihydro-2H-pyran-2-ones were studied to explore the existence of such interactions. Three of the Michael addition products were isolated and tested over PC3 (human prostate cancer) and MCF-7 (human breast adenocarcinoma) cancer cell lines and no cytotoxicity was observed. It was revealed that biological activity depends on the existence of a Michael acceptor, but potency probably depends upon the 3D structure of the substituent on lactone ring. The primary chemical-quantum properties of the lactones were also calculated using the Spartan'08 computer program. © 2010 Elsevier Inc. All rights reserved.Article Citation - WoS: 50Synthesis of Aminopropyl Triethoxysilane-Functionalized Silica and Its Application in Speciation Studies of Vanadium(iv) and Vanadium(v)(Elsevier Ltd., 2011) Erdem, Aslı; Shahwan, Talal; Çağır, Ali; Eroğlu, Ahmet EminA solid phase extraction sorbent, aminopropyl triethoxysilane-functionalized silica was prepared and used for vanadium speciation prior to inductively coupled plasma mass spectrometric determination. The necessary sorption parameters such as sorption pH, reaction temperature, sorbent amount and sample volume were optimized. The sorption for V(V) and V(IV) under the optimized conditions was 98% (±1) and was lower than 10%, respectively. The sorption process was investigated both from a kinetic perspective and also in terms of Freundlich, Dubinin-Radushkevich and Langmuir isotherm models to characterize the uptake of vanadate ion by the functionalized silica. Desorption from the sorbent was realized with 0.5 mol L−1 thiourea prepared in 0.2 mol L−1 HCl. Among the possible interfering species tested, Te(IV), Se(IV), Se(VI) and Fe(III) showed interference effects with V(V) signal. The validity of the method was first checked via spike recovery experiments with four different types of water; namely ultra pure, bottled drinking, tap, and sea water for different concentrations of V(V). The percent recovery values changed between 87 and 108 for all water types. The accuracy of the proposed methodology was also checked by analyzing a standard reference material (NIST, SRM 1643e) and a good agreement was found between the determined and the certified value. The proposed methodology has also been shown to be applicable for the separate sorption of V(V) in the absence/presence of V(IV) and for the sorption of both V(IV) and V(V) in waters. The amount of V(IV) can then be determined from the difference.Article Citation - WoS: 46Synthesis, Characterization and Application of a Novel Mercapto- and Amine-Bifunctionalized Silica for Speciation/Sorption of Inorganic Arsenic Prior To Inductively Coupled Plasma Mass Spectrometric Determination(Elsevier Ltd., 2011) Boyacı, Ezel; Çağır, Ali; Shahwan, Talal; Eroğlu, Ahmet EminA bifunctional sorbent, (NH2 + SH)silica, containing both amine and mercapto functionalities was prepared by modification of silica gel with 3-(triethoxysilyl)propylamine and (3-mercaptopropyl)trimethoxysilane. In addition to the bifunctional sorbent, silica gel was modified individually with the functional mercapto- and amino-silanes, and the mono-functional sorbents, namely (SH)silica and (NH2)silica, were also mechanically mixed ((NH2)silica + (SH)silica) for the sake of comparison of sorption performances. It has been demonstrated that (SH)silica shows quantitative sorption only to As(III) at two pH values, 1.0 and 9.0, while (NH2)silica displays selectivity only towards As(V) at pH 3.0. On the other hand, the bifunctional (NH2 + SH)silica possesses the efficient features of the two mono-functionalized sorbents; for example, it retains As(III) at a wider pH range, from 1.0 to at least 9.0 with the exception at pH 2.0, and it also shows quantitative sorption to As(V) at pH 3.0. This property gives the bifunctional (NH2 + SH)silica a better flexibility in terms of sorption performance as a function of solution pH. The mechanically mixed (NH2)silica + (SH)silica exhibits a similar but less efficient sorption behavior compared to the bifunctional sorbent. Desorption of both As(III) and As(V) species can be realized using 0.5 M NaOH. The validity of the proposed method was checked through the analysis of a standard reference material and a good correlation was obtained between the certified (26.67 μg L−1) and determined (27.53 ± 0.37 μg L−1) values. Spike recovery tests realized with ultrapure water (93.0 ± 2.3%) and drinking water (86.9 ± 1.2%) also confirmed the applicability of the method.