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  1. Article ; Online: Rational design of metabolically stable HDAC inhibitors: An overhaul of trifluoromethyl ketones.

    Riddhidev, Banerjee / Endri, Karaj / Sabitri, Lamichhane / Kotsull Lauren, N / Nishanth, Kuganesan / Dragan, Isailovic / Mary Kay H, Pflum / James, Slama / William, Taylor / L M Viranga, Tillekeratne

    European journal of medicinal chemistry

    2022  Volume 244, Page(s) 114807

    Abstract: Epigenetic regulation of gene expression using histone deacetylase (HDAC) inhibitors is a promising strategy for developing new anticancer agents. The most common HDAC inhibitors are hydroxamates, which, though highly potent, have limitations due to ... ...

    Abstract Epigenetic regulation of gene expression using histone deacetylase (HDAC) inhibitors is a promising strategy for developing new anticancer agents. The most common HDAC inhibitors are hydroxamates, which, though highly potent, have limitations due to their poor pharmacokinetic properties and lack of isoform selectivity. Trifluoromethylketones (TFMK) developed as alternatives to hydroxamates are rapidly metabolized to inactive trifluoromethyl alcohols in vivo, which prevented their further development as potential drug candidates. In order to overcome this limitation, we designed trifluoropyruvamides (TFPAs) as TFMK surrogates. The presence of an additional electron withdrawing group next to the ketone carbonyl group made the hydrate form of the ketone more stable, thus preventing its metabolic reduction to alcohol in vivo. In addition, this structural modification reduces the potential of the TFMK group to act as a covalent warhead to eliminate off-target effects. Additional structural changes in the cap group of the inhibitors gave analogues with IC
    MeSH term(s) Histone Deacetylase Inhibitors/pharmacology ; Histone Deacetylase Inhibitors/chemistry ; Ketones/pharmacology ; Epigenesis, Genetic ; Repressor Proteins/metabolism ; Hydroxamic Acids/chemistry ; Protein Isoforms/metabolism
    Chemical Substances Histone Deacetylase Inhibitors ; Ketones ; Repressor Proteins ; Hydroxamic Acids ; Protein Isoforms
    Language English
    Publishing date 2022-10-05
    Publishing country France
    Document type Journal Article
    ZDB-ID 188597-2
    ISSN 1768-3254 ; 0009-4374 ; 0223-5234
    ISSN (online) 1768-3254
    ISSN 0009-4374 ; 0223-5234
    DOI 10.1016/j.ejmech.2022.114807
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.B 784: Show issues Location:
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  2. Article: Electropolymerized Pyrrole-Based Conductive Polymeric Ionic Liquids and Their Application for Solid-Phase Microextraction

    Devasurendra, Amila M / Cheng Zhang / Jared L. Anderson / Jon R. Kirchhoff / Joshua A. Young / L. M. Viranga Tillekeratne

    ACS applied materials & interfaces. 2017 July 26, v. 9, no. 29

    2017  

    Abstract: Pyrrole was covalently bonded to 1-methyl and 1-benzylimidazolium ionic liquids (ILs) via an N-substituted alkyl linkage to prepare electropolymerizable IL monomers with excellent thermal stability. The methylimidazolium IL, [pyrrole-C6MIm]+, was then ... ...

    Abstract Pyrrole was covalently bonded to 1-methyl and 1-benzylimidazolium ionic liquids (ILs) via an N-substituted alkyl linkage to prepare electropolymerizable IL monomers with excellent thermal stability. The methylimidazolium IL, [pyrrole-C6MIm]+, was then electropolymerized on macro- and microelectrode materials to form conductive polymeric IL (CPIL)-modified surfaces. Electrochemical characterization of a 1.6 mm diameter Pt disk electrode modified with poly[pyrrole-C6MIm]+ demonstrated a selective uptake for an anionic redox probe while rejecting a cationic redox probe. Furthermore, electropolymerization of [pyrrole-C6MIm]+ doped with single-walled carbon nanotubes (SWNT) on 125 μm platinum wires produced 42 μm thick poly[pyrrole-C6MIm]+/SWNT films compared to 17 μm in the absence of SWNT and 5 μm for the previously reported poly[thiophene-C6MIm]+ coatings. The poly[pyrrole-C6MIm]+/SWNT films were prepared with reproducible thicknesses as well as thermal properties sufficient for high-temperature applications, such as solid-phase microextraction (SPME) with gas chromatographic analysis. The utilization of the CPIL sorbent materials in SPME experiments provided excellent extraction efficiencies and selectivity toward organic aromatic analytes. The CPIL sorbent coatings also yielded outstanding fiber-to-fiber reproducibility on the basis of extraction efficiencies and improved response for a range of analytes relative to commercial 100 μm poly(dimethylsiloxane) fibers when normalized for differences in film thickness. Poly[pyrrole-C6MIm]+ CPIL coatings doped with SWNT are therefore promising new sorbent materials for SPME analyses.
    Keywords carbon nanotubes ; chemical bonding ; coatings ; electrochemistry ; electrodes ; gas chromatography ; ionic liquids ; platinum ; pyrroles ; solid phase microextraction ; sorbents ; thermal stability
    Language English
    Dates of publication 2017-0726
    Size p. 24955-24963.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1944-8252
    DOI 10.1021/acsami.7b05793
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  3. Article: Conductive polymeric ionic liquids for electroanalysis and solid-phase microextraction

    Young, Joshua A / Amila M. Devasurendra / Cheng Zhang / Jared L. Anderson / Jon R. Kirchhoff / L.M. Viranga Tillekeratne

    Analytica chimica acta. 2016 Mar. 03, v. 910

    2016  

    Abstract: Three novel electropolymerizable thiophene-based ionic liquids (ILs) were synthesized and characterized as potential candidates for developing selective extraction media for chemical analysis. Electropolymerization of the bis[(trifluoromethyl)sulfonyl] ... ...

    Abstract Three novel electropolymerizable thiophene-based ionic liquids (ILs) were synthesized and characterized as potential candidates for developing selective extraction media for chemical analysis. Electropolymerization of the bis[(trifluoromethyl)sulfonyl]imide ([NTf2]-) analogs successfully produced uniform polymeric thin-films on macro- and microelectrode substrates from both vinyl and methylimidazolium IL monomer derivatives. The resultant conducting polymer IL (CPIL) films were characterized by electrochemical methods and found to exhibit attractive behavior towards anionic species while simultaneously providing an exclusion barrier toward cationic species. Thermogravimetric analysis of the thiophene-based IL monomers established a high thermal stability, particularly for the methylimidazolium IL, which was stable until temperatures above 350 °C. Subsequently, the methylimidazolium IL was polymerized on 125 μm platinum wires and utilized for the first time as a sorbent coating for headspace solid-phase microextraction (HS-SPME). The sorbent coating was easily prepared in a reproducible manner, provided high thermal stability, and allowed for the gas chromatographic analysis of polar analytes. The normalized response of the poly[thioph-C6MIm][NTf2]-based sorbent coating exhibited higher extraction efficiency compared to an 85 μm polyacrylate fiber and excellent fiber-to-fiber reproducibility. Therefore, the electropolymerizable thiophene-based ILs were found to be viable new materials for the preparation of sorbent coatings for HS-SPME.
    Keywords coatings ; electrochemistry ; gas chromatography ; headspace analysis ; ionic liquids ; platinum ; polyacrylic acid ; solid phase microextraction ; temperature ; thermal stability ; thermogravimetry
    Language English
    Dates of publication 2016-0303
    Size p. 45-52.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1483436-4
    ISSN 1873-4324 ; 0003-2670
    ISSN (online) 1873-4324
    ISSN 0003-2670
    DOI 10.1016/j.aca.2016.01.017
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  4. Article: Bioactivities of n-hexane fraction of Vateria copallifera and GC–MS analysis of its phytoconstituents

    Samaradivakara, Saroopa P / L.M. Viranga Tillekeratne / O.V.D.S. Jagathpriya Weerasena / Qasim Alhadidi / Radhika Samarasekera / Shiroma M. Handunnetti / William R. Taylor / Zahoor A. Shah

    Industrial crops and products. 2017 Mar., v. 97

    2017  

    Abstract: Vateria copallifera (Retz.) is an important timber source belonging to the family of Dipterocarpaceae, which is acknowledged as a plant family rich in a variety of bioactive chemical constituents. This study was conducted to evaluate the chemical ... ...

    Abstract Vateria copallifera (Retz.) is an important timber source belonging to the family of Dipterocarpaceae, which is acknowledged as a plant family rich in a variety of bioactive chemical constituents. This study was conducted to evaluate the chemical composition and the bioactivities of the non-polar n-hexane fraction obtained by dry column chromatography of the hexane extract of V. copallifera bark. n-Hexane fraction was analyzed by gas chromatography–mass spectrometry (GC–MS). Cytotoxicity was measured by the MTT assay against HeLa, MCF7, HepG2, HCT116 and SK-Mel 5 cell lines. The neuroprotective effect of the n-hexane fraction was assessed by oxygen glucose deprivation (OGD) assay using PC12 cells. Nitric oxide (NO) inhibitory activity was investigated on lipopolysaccharide (LPS)-stimulated microglial cells. The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and oxygen radical absorbance capacity (ORAC) assays. Cholinesterase inhibitory activity was evaluated using acetylcholinesterase and butyrylcholinesterase inhibitory assays and protease inhibitory activity was evaluated by α-chymotrypsin and elastase enzyme inhibitory assays. Decane, dodecane, undecanes, naphthalene derivative, heptadecane, squalene, copaene and eicosane were identified as the major constituents (>2% peak area). The n-hexane fraction exhibited a concentration-dependent increase in the neuroprotective activity although it was not significant (p>0.05) at the tested concentrations. Contradictorily, the n-hexane fraction treated microglia cells released significantly (p<0.05) higher levels of NO into the medium (>100%) compared to the control counterpart. However, further studies are needed to assess the neuroprotective activity and to determine the cause of the increase of NO. The n-hexane fraction showed no cytotoxicity, antioxidant, ChE, protease and GST enzyme inhibitory activity at the tested concentrations. To our knowledge, this is the first report on the analysis of the chemical composition and the bioactive potential of the non-polar n-hexane fraction obtained by chromatography of the hexane extract of V. copallifera bark.
    Keywords 2,2-diphenyl-1-picrylhydrazyl ; acetylcholinesterase ; antioxidants ; bark ; chemical analysis ; chemical composition ; chemical constituents of plants ; cholinesterase ; chymotrypsin ; cytotoxicity ; decane ; elastase ; enzyme inhibition ; gas chromatography-mass spectrometry ; glucose ; hexane ; lipopolysaccharides ; naphthalene ; neuroglia ; neuroprotective effect ; nitric oxide ; oxygen ; oxygen radical absorbance capacity ; squalene ; Vateria
    Language English
    Dates of publication 2017-03
    Size p. 87-92.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1132158-1
    ISSN 1872-633X ; 0926-6690
    ISSN (online) 1872-633X
    ISSN 0926-6690
    DOI 10.1016/j.indcrop.2016.12.011
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    Z 5577: Show issues

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  5. Article ; Online: Small-Molecule Ferroptotic Agents with Potential to Selectively Target Cancer Stem Cells

    William R. Taylor / Sara R. Fedorka / Ibtissam Gad / Ronit Shah / Hanan D. Alqahtani / Radhika Koranne / Nishanth Kuganesan / Samkeliso Dlamini / Tim Rogers / Ayad Al-Hamashi / Veronika Kholodovych / Yusuf Barudi / Damian Junk / Maisha S. Rashid / Mark W. Jackson / L. M. Viranga Tillekeratne

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 14

    Abstract: Abstract Effective management of advanced cancer requires systemic treatment including small molecules that target unique features of aggressive tumor cells. At the same time, tumors are heterogeneous and current evidence suggests that a subpopulation of ...

    Abstract Abstract Effective management of advanced cancer requires systemic treatment including small molecules that target unique features of aggressive tumor cells. At the same time, tumors are heterogeneous and current evidence suggests that a subpopulation of tumor cells, called tumor initiating or cancer stem cells, are responsible for metastatic dissemination, tumor relapse and possibly drug resistance. Classical apoptotic drugs are less effective against this critical subpopulation. In the course of generating a library of open-chain epothilones, we discovered a new class of small molecule anticancer agents that has no effect on tubulin but instead kills selected cancer cell lines by harnessing reactive oxygen species to induce ferroptosis. Interestingly, we find that drug sensitivity is highest in tumor cells with a mesenchymal phenotype. Furthermore, these compounds showed enhanced toxicity towards mesenchymal breast cancer populations with cancer stem cell properties in vitro. In summary, we have identified a new class of small molecule ferroptotic agents that warrant further investigation.
    Keywords Medicine ; R ; Science ; Q
    Subject code 610
    Language English
    Publishing date 2019-04-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
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