Displaying publications 1 - 20 of 42 in total

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  1. Rahima ZA, Abdul Halim SN, How FN
    Acta Crystallogr E Crystallogr Commun, 2015 Sep 1;71(Pt 9):o647.
    PMID: 26396883 DOI: 10.1107/S2056989015014462
    The title compound, C14H19NS2, crystallizes in the thione form with the presence of a C=S bond. The piperidine ring adopts a chair conformation. The dihedral angle between the essentially planar di-thio-carbamate and p-tolyl fragments is 74.46 (10)°.
    Matched MeSH terms: Carbamates
  2. Khoo KS, Ooi CW, Chew KW, Foo SC, Show PL
    Bioresour Technol, 2021 Feb;322:124520.
    PMID: 33348114 DOI: 10.1016/j.biortech.2020.124520
    Ionic liquids (ILs) have emerged as an alternative solvent used in the bioprocessing of microalgae for recovery of valuable biomolecules. The aim of this work is to extract fucoxanthin from Chaetoceros calcitrants (C. calcitrans) by using the readily distillable CO2-based alkyl carbamate ILs. The degree of cell permeabilization was analysed by the quantification of extracted fucoxanthin and the analyses of cell surface morphology. Among the tested CO2-based alkyl carbamate ILs, diallylammonium diallylcarbamate (DACARB) extraction system gave the maximal yield of fucoxanthin at 17.51 mg/g under the optimal extraction conditions [90% (v/v), 3 min and 25 °C]. Moreover, the extracted fucoxanthin fraction exhibited the satisfactory antioxidant activities. The recyclability of DACARB was demonstrated in the multiple batches of fucoxanthin extraction. Hence, CO2-based alkyl carbamate ILs can prospectively substitute conventional organic solvents in the downstream processing of bioactive compounds from microalgae.
    Matched MeSH terms: Carbamates
  3. Wu J, Pistolozzi M, Liu S, Tan W
    Bioorg Med Chem, 2020 03 01;28(5):115324.
    PMID: 32008882 DOI: 10.1016/j.bmc.2020.115324
    Rivastigmine, a dual inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), has been approved by U.S. Food and Drug Administration to treat Alzheimer's disease (AD) and Parkinson's disease (PD) dementia. In the current work, a bambuterol derivative lacking one of the carbamoyloxy groups on the benzene ring (BMC-1) and its analogues were synthesized using 1-(3-hydroxyphenyl) ethan-1-one and 1-(4-hydroxyphenyl) ethan-1-one as starting materials. In-vitro cholinesterase assay established that nine compounds were more potent to inhibit both electric eel AChE and equine serum BChE than rivastigmine under the same experimental conditions. Further study confirmed that among the nine carbamates, BMC-3 (IC50(AChE) = 792 nM, IC50(BChE) = 2.2 nM) and BMC-16 (IC50(AChE) = 266 nM, IC50(BChE) = 10.6 nM) were excellent cholinesterase inhibitors with potential of permeating through the blood-brain barrier. These carbamates could be used as potential dual inhibitors of AChE and BChE and to discover novel drugs for the treatment of AD and PD dementia.
    Matched MeSH terms: Carbamates/chemical synthesis; Carbamates/pharmacology*; Carbamates/chemistry
  4. Zaldi NB, Hussen RSD, Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Jun 01;73(Pt 6):842-848.
    PMID: 28638641 DOI: 10.1107/S2056989017006855
    The title compound, [Sn(CH3)2(C5H8NOS2)2], has the Sn(IV) atom bound by two methyl groups which lie over the weaker Sn-S bonds formed by two asymmetrically chelating di-thio-carbamate ligands so that the coordination geometry is skew-trapezoidal bipyramidal. The most prominent feature of the mol-ecular packing are secondary Sn⋯S inter-actions [Sn⋯S = 3.5654 (7) Å] that lead to centrosymmetric dimers. These are connected into a three-dimensional architecture via methyl-ene-C-H⋯S and methyl-C-H⋯O(morpholino) inter-actions. The Sn⋯S inter-actions are clearly evident in the Hirshfeld surface analysis of the title compound along with a number of other inter-molecular contacts.
    Matched MeSH terms: Carbamates
  5. Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Feb 01;73(Pt 2):260-265.
    PMID: 28217355 DOI: 10.1107/S2056989017001098
    The complete mol-ecule of the title compound, [Sn(C4H9)2(C5H10NOS2)2], is generated by a crystallographic mirror plane, with the SnIV atom and the two inner methyl-ene C atoms of the butyl ligands lying on the mirror plane; statistical disorder is noted in the two terminal ethyl groups, which deviate from mirror symmetry. The di-thio-carbamate ligand coordinates to the metal atom in an asymmetric mode with the resulting C2S4 donor set defining a skew trapezoidal bipyramidal geometry; the n-butyl groups are disposed to lie over the longer Sn-S bonds. Supra-molecular chains aligned along the a-axis direction and sustained by methyl-ene-C-H⋯S(weakly coordinating) inter-actions feature in the mol-ecular packing. A Hirshfeld surface analysis reveals the dominance of H⋯H contacts in the crystal.
    Matched MeSH terms: Carbamates
  6. Tan SL, Lee SM, Heard PJ, Halcovitch NR, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Feb 01;73(Pt 2):213-218.
    PMID: 28217345 DOI: 10.1107/S2056989017000755
    The title compound, [Re(C3H6NS2)(C2H3N)(CO)3], features an octa-hedrally coordinated Re(I) atom within a C3NS2 donor set defined by three carbonyl ligands in a facial arrangement, an aceto-nitrile N atom and two S atoms derived from a symmetrically coordinating di-thio-carbamate ligand. In the crystal, di-thio-carbamate-methyl-H⋯O(carbon-yl) inter-actions lead to supra-molecular chains along [36-1]; both di-thio-carbamate S atoms participate in intra-molecular methyl-H⋯S inter-actions. Further but weaker aceto-nitrile-C-H⋯O(carbonyl) inter-actions assemble mol-ecules in the ab plane. The nature of the supra-molecular assembly was also probed by a Hirshfeld surface analysis. Despite their weak nature, the C-H⋯O contacts are predominant on the Hirshfeld surface and, indeed, on those of related [Re(CO)3(C3H6NS2)L] structures.
    Matched MeSH terms: Carbamates
  7. Poplaukhin P, Arman HD, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Jul 01;73(Pt 8):1162-1166.
    PMID: 28932428 DOI: 10.1107/S2056989017010179
    The title compound, {[Zn(C9H11N2S2)2]·0.5C6H7N} n , comprises two independent, but chemically similar, Zn[S2CN(Et)CH2py]2 residues and a 4-methyl-pyridine solvent mol-ecule in the asymmetric unit. The Zn-containing units are connected into a one-dimensional coordination polymer (zigzag topology) propagating in the [010] direction, with one di-thio-carbamate ligand bridging in a μ2-κ(3) mode, employing one pyridyl N and both di-thio-carbamate S atoms, while the other is κ(2)-chelating. In each case, the resultant ZnNS4 coordination geometry approximates a square pyramid, with the pyridyl N atom in the apical position. In the crystal, the chains are linked into a three-dimensional architecture by methyl- and pyridyl-C-H⋯S, methyl-ene-C-H⋯N(pyrid-yl) and pyridyl-C-H⋯π(ZnS2C) inter-actions. The connection between the chain and the 4-methyl-pyridine solvent mol-ecule is of the type pyridyl-C-H⋯N(4-methyl-pyridine).
    Matched MeSH terms: Carbamates
  8. Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Oct 1;72(Pt 10):1480-1487.
    PMID: 27746946
    The crystal and mol-ecular structures of two tri-phenyl-tin di-thio-carbamates, [Sn(C6H5)3(C16H16NS2)], (I), and [Sn(C6H5)3(C7H14NO2S2)], (II), are described. In (I), the di-thio-carbamate ligand coordinates the Sn(IV) atom in an asymmetric manner, leading to a highly distorted trigonal-bipyramidal coordination geometry defined by a C3S2 donor set with the weakly bound S atom approximately trans to one of the ipso-C atoms. A similar structure is found in (II), but the di-thio-carbamate ligand coordinates in an even more asymmetric fashion. The packing in (I) features supra-molecular chains along the c axis sustained by C-H⋯π inter-actions; chains pack with no directional inter-actions between them. In (II), supra-molecular layers are formed, similarly sustained by C-H⋯π inter-actions; these stack along the b axis. An analysis of the Hirshfeld surfaces for (I) and (II) confirms the presence of the C-H⋯π inter-actions but also reveals the overall dominance of H⋯H contacts in the respective crystals.
    Matched MeSH terms: Carbamates; Phenylcarbamates
  9. Lee HL, Tien WD, Omar B
    PMID: 9322308
    The insecticide resistance status of 4 strains of adult male Blattella germanica, viz M (Malacca), E (England), F (restaurant) and K (cafeteria) against malathion and bendiocarb compared with a reference susceptible strain (S) was determined by using a modified WHO bioassay method. The results indicated that all the 4 strains were resistant to the insecticides albeit in different degrees. Resistance ratios for malathion ranged from 1.85-41.07-fold, whereas that of bendiocarb ranged from 1.68-4.83-fold. The biochemical microplate enzyme assays technique employed indicated that the resistance in M and E strains were attributed to acetylcholinesterase insensitivity. Multiple resistance was not detected in any of the 4 strains. Parameters of the identified resistance mechanism correlated well with the observed level of resistance. Agar gel electrophoresis showed that variations in esterase isoenzymes did not confer organophosphate and carbamate resistance to the 4 strains.
    Matched MeSH terms: Carbamates*; Phenylcarbamates*
  10. Chen YP, Sudderuddin KI
    PMID: 749224
    Toxicity tests carried out on the larvae of A. aegypti and C. quinquefasciatus showed the former to be more tolerant of all insecticides tested, the order of toxicity being temephos greater than DDT greater than DDVP greater than malathion greater than lindane greater than carbaryl; also the second instar larvae of A. aegypti were more susceptible than fourth instar larvae. Enzyme kinetic studies on the total non-specific esterases and CarEs of adults and larvae of both species showed the Km values for total esterases of adult A. aegypti to be 0.333 mM vs 0.233 mM for C. quinquefasciatus; for adult CarEs it was 0.250 mM vs 0.220 mM. For total larval esterases of A. aegypti it was 0.112 mM vs 0.175 mM for C. quinquefasciatus: and for larval CarES it was 0.159 mM vs 0.213 mM respectively. Although some correlation between in vivo toxicity (LD50 values) and in vitro esterase inhibition (I50 values) between species could be discerned, overall correlation could not be established.
    Matched MeSH terms: Carbamates*
  11. Gan S, Zakaria S, Chia CH, Chen RS, Ellis AV, Kaco H
    PLoS One, 2017;12(3):e0173743.
    PMID: 28296977 DOI: 10.1371/journal.pone.0173743
    Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet-visible (UV-Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products.
    Matched MeSH terms: Carbamates/chemistry*
  12. Ruzilawati AB, Wahab MS, Imran A, Ismail Z, Gan SH
    J Pharm Biomed Anal, 2007 Apr 11;43(5):1831-5.
    PMID: 17240100
    In this study, the development and validation of a high-performance liquid chromatography (HPLC) assay for determination of repaglinide concentration in human plasma for pharmacokinetic studies is described. Plasma samples containing repaglinide and an internal standard, indomethacin were extracted with ethylacetate at pH 7.4. The recovery of repaglinide was 92%+/-55.31. Chromatographic separations were performed on Purospher STAR C-18 analytical column (4.8 mm x 150 mm; 5 microm particle size). The mobile phase composed of acetonitrile-ammonium formate (pH 2.7; 0.01 M) (60:40, v/v). The flow rate was 1 ml/min. The retention time for repaglinide and indomethacin were approximately 6.2 and 5.3 min, respectively. Calibration curves of repaglinide were linear in the concentration range of 20-200 ng/ml in plasma. The limits of detection and quantification were 10 ng/ml and 20 ng/ml, respectively. The inter-day precision was from 5.21 to 11.84% and the intra-day precision ranged from 3.90 to 6.67%. The inter-day accuracy ranged 89.95 to 105.75% and intra-day accuracy ranged from 92.37 to 104.66%. This method was applied to determine repaglinide concentration in human plasma samples for a pharmacokinetic study.
    Matched MeSH terms: Carbamates/blood*; Carbamates/pharmacokinetics*; Carbamates/chemistry
  13. Ahmad J, Abdul Halim SN, How FN
    Acta Crystallogr E Crystallogr Commun, 2015 Jun 1;71(Pt 6):o410-1.
    PMID: 26090195 DOI: 10.1107/S2056989015009159
    The title compound, Ph3(PhCH2)P(+)·Cl(-)·H2O, was obtained unintentionally as the product of an attempted synthesis of a silver di-thio-carbamate complex using benzyl-tri-phenyl-phospho-nium as the counter-ion. The asymmetric unit consists of a phospho-nium cation and a chloride anion, and a water mol-ecule of crystallization. In the crystal, the chloride ion is linked to the water mol-ecule by an O-H⋯Cl hydrogen bond. The three units are further linked via C-H⋯Cl and C-H⋯O hydrogen bonds and C-H⋯ π inter-actions, forming a three-dimensional structure.
    Matched MeSH terms: Carbamates
  14. Suwardi SA, Lee SM, Lo KM, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Mar 01;73(Pt 3):429-433.
    PMID: 28316825 DOI: 10.1107/S2056989017002705
    The title compound, [Cd2(C8H8NS2)4], is a centrosymmetric dimer with both chelating and μ2-tridentate di-thio-carbamate ligands. The resulting S5 donor set defines a Cd(II) coordination geometry inter-mediate between square-pyramidal and trigonal-bipyramidal, but tending towards the former. The packing features C-H⋯S and C-H⋯π inter-actions, which generate a three-dimensional network. The influence of these inter-actions, along with intra-dimer π-π inter-actions between chelate rings, has been investigated by an analysis of the Hirshfeld surface.
    Matched MeSH terms: Carbamates
  15. Mohamad R, Awang N, Kamaludin NF, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2018 Mar 01;74(Pt 3):302-308.
    PMID: 29765711 DOI: 10.1107/S2056989018001901
    The crystal and mol-ecular structures of the two title organotin di-thio-carbamate compounds, [Sn(C4H9)2(C7H14NO2S2)2], (I), and [Sn(C6H5)3(C5H10NOS2)], (II), are described. Both structures feature asymmetrically bound di-thio-carbamate ligands leading to a skew-trapezoidal bipyramidal geometry for the metal atom in (I) and a distorted tetra-hedral geometry in (II). The complete mol-ecule of (I) is generated by a crystallographic twofold axis (Sn site symmetry 2). In the crystal of (I), mol-ecules self-assemble into a supra-molecular array parallel to (10-1) via methyl-ene-C-H⋯O(meth-oxy) inter-actions. In the crystal of (II), supra-molecular dimers are formed via pairs of weak phenyl-C-H⋯π(phen-yl) contacts. In each of (I) and (II), the specified assemblies connect into a three-dimensional architecture without directional inter-actions between them. Hirshfeld surface analyses confirm the importance of H⋯H contacts in the mol-ecular packing of each of (I) and (II), and in the case of (I), highlight the importance of short meth-oxy-H⋯H(but-yl) contacts between layers.
    Matched MeSH terms: Carbamates
  16. Mohamad R, Awang N, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Aug 1;72(Pt 8):1130-7.
    PMID: 27536397 DOI: 10.1107/S2056989016011385
    The crystal and mol-ecular structures of two di-phenyl-tin bis-(di-thio-carbamate)s, [Sn(C6H5)2(C5H10NOS2)2], (I), and [Sn(C6H5)2(C7H14NO2S2)2], (II), are described. In (I), in which the metal atom lies on a twofold rotation axis, the di-thio-carbamate ligand coordinates with approximately equal Sn-S bond lengths and the ipso-C atoms of the Sn-bound phenyl groups occupy cis-positions in the resulting octa-hedral C2S4 donor set. A quite distinct coordination geometry is noted in (II), arising as a result of quite disparate Sn-S bond lengths. Here, the four S-donors define a trapezoidal plane with the ipso-C atoms lying over the weaker of the Sn-S bonds so that the C2S4 donor set defines a skewed trapezoidal bipyramid. The packing of (I) features supra-molecular layers in the ab plane sustained by methyl-ene-C-H⋯π(Sn-ar-yl) inter-actions; these stack along the c-axis direction with no specific inter-actions between them. In (II), supra-molecular chains along the b-axis direction are formed by methyl-ene-C-O(ether) inter-actions; these pack with no directional inter-actions between them. A Hirshfeld surface analysis was conducted on both (I) and (II) and revealed the dominance of H⋯H inter-actions contributing to the respective surfaces, i.e. >60% in each case, and other features consistent with the description of the mol-ecular packing above.
    Matched MeSH terms: Carbamates
  17. Chowdhury MA, Jahan I, Karim N, Alam MK, Abdur Rahman M, Moniruzzaman M, et al.
    Biomed Res Int, 2014;2014:145159.
    PMID: 24711991 DOI: 10.1155/2014/145159
    In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC), and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50%) of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb) and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl) were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40-48%, 35-43%, and 30-45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85-90%, 80-91%, and 90-95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80-95% of some pesticides.
    Matched MeSH terms: Carbamates/radiation effects*; Carbamates/chemistry*
  18. Ruzilawati AB, Mohd Suhaimi AW, Gan SH
    J Clin Pharm Ther, 2010 Feb;35(1):105-12.
    PMID: 20175819 DOI: 10.1111/j.1365-2710.2009.01042.x
    To estimate population pharmacokinetic parameters of repaglinide in 121 healthy Malaysian volunteers.
    Matched MeSH terms: Carbamates/blood; Carbamates/pharmacokinetics*
  19. Latif LA, Surin J
    Jpn. J. Med. Sci. Biol., 1993 Oct-Dec;46(5-6):203-14.
    PMID: 8051807
    Efficacy of eight recently developed and used anthelmintics of the benzimidazole carbamates; mebendazole, flubendazole, oxfendazole, albendazole, oxibendazole, 790163 proflubendazole, 780118 "cyanide" benzimidazole and 780120 "selenium" benzimidazole was tested orally against the enteral immature larval and adult stages of Trichinella spiralis in mice. Six of these derivatives of methyl benzimidazole-2-carbamates have an aryl and two have an alkyl substituent at the 5'-position of the parent benzimidazole ring. The nature of these substituents was found to be related to the antitrichinellous activity of the compounds. Compounds with the 5'-substituent linked to the parent benzimidazole ring by either a carbon, sulfur or an oxygen atom are more potent than those bridged by selenium or by the carbon with an attached-CN group. The result clearly indicates that the benzimidazoles are invariably more potent against immature enteral phase than the adult worms. This finding would be of importance in a targeted synthesis of new, effective derivatives of benzimidazole, e.g., in the screening for more important tissue-dwelling nematodes like filarial worms.
    Matched MeSH terms: Carbamates/pharmacology*; Carbamates/chemistry
  20. Ruzilawati AB, Gan SH
    Pharmacology, 2010;85(6):357-64.
    PMID: 20523106 DOI: 10.1159/000302731
    AIM: To investigate the effects of CYP3A4 and CYP2C8 enzymes on repaglinide's pharmacokinetics in healthy Malaysian subjects.

    METHODS: Subjects (n = 121) received oral repaglinide (4 mg). Blood samples were taken at 0, 30, 60, 120, 180 and 240 min and serum concentrations of repaglinide were determined using high-performance liquid chromatography. Subjects were also genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for CYP3A4*4, *5 and*18 and by an allele-specific multiplex PCR for CYP2C8*2, *3, *4 and *5 alleles.

    RESULTS: The allele frequencies of CYP2C8*1, *2, *3, *4 and *5 were 95.04, 0.40, 0.40, 0 and 4.13%, respectively. The frequencies of the CYP3A4*1, *4, *5 and *18 alleles were 97.93, 0, 0 and 2.07%, respectively. CYP2C8 and CYP3A4 genotypes were not significantly associated with repaglinide's blood glucose-lowering effect. However, the CYP3A4 genotype significantly influenced some of repaglinide's pharmacokinetics, where the mean elimination rate constant was 44.0% lower (p = 0.04) and the mean half-life was 33.8% higher (p = 0.04) in subjects with the CYP3A4*1/*18 genotype as compared to those with the normal CYP3A4*1/*1 genotype. This result confirms that CYP3A4 plays a large role in metabolizing repaglinide.

    CONCLUSION: Genetic polymorphisms of CYP3A4, specifically CYP3A4*18, play a major role in contributing to the interindividual variability in repaglinide's pharmacokinetics.

    Matched MeSH terms: Carbamates/administration & dosage; Carbamates/blood; Carbamates/pharmacokinetics*; Carbamates/pharmacology
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