The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Stephen W. C. Chung - One of the best experts on this subject based on the ideXlab platform.
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Development and validation of a method for determination of residues of 15 pyrethroids and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Stephen W. C. ChungAbstract:This paper reports a novel approach for the detection, confirmation, and quantification of 15 selected pyrethroid pesticides, including pyrethins, and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS–MS). The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure that combines isolation of the pesticides and sample cleanup in a single step. Analysis of pyrethroids and dithiocarbamate metabolites was performed by UPLC–MS–MS operated with electrospray and atmospheric pressure chemical ionization, respectively. Two specific precursor–product ion transitions were acquired per target compound in multiple reaction monitoring (MRM) mode. Such acquisition achieved the minimum number of identification points according to European Commission (EC) document no. SANCO/10684/2009, thus fulfilling the EC point system requirement for identification of contaminants in samples. The method was validated with a variety of food samples. Calibration curves were linear and covered from 1 to 800 μg kg^−1 in the sample for all target compounds. Average recoveries, measured at mass fractions of 10 and 100 μg kg^−1 for pyrethroids and 5 and 50 μg kg^−1 for dithiocarbamate metabolites, were in the range of 70–120% for all target compounds with relative standard deviations below 20%. Method limits of quantification (MLOQ) were 10 μg kg^−1 and 5 μg kg^−1 for pyrethroids and dithiocarbamate metabolites, respectively. The method has been successfully applied to the analysis of 600 food samples in the course of the first Hong Kong total diet study with pyrethroids and metabolites of Dithiocarbamates being the pesticides determined. Figure UPLC–MS/MS chromatogram for twenty target analytes spiked at the MLOQ level
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development and validation of a method for determination of residues of 15 pyrethroids and two metabolites of Dithiocarbamates in foods by ultra performance liquid chromatography tandem mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Stephen W. C. ChungAbstract:This paper reports a novel approach for the detection, confirmation, and quantification of 15 selected pyrethroid pesticides, including pyrethins, and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS–MS). The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure that combines isolation of the pesticides and sample cleanup in a single step. Analysis of pyrethroids and dithiocarbamate metabolites was performed by UPLC–MS–MS operated with electrospray and atmospheric pressure chemical ionization, respectively. Two specific precursor–product ion transitions were acquired per target compound in multiple reaction monitoring (MRM) mode. Such acquisition achieved the minimum number of identification points according to European Commission (EC) document no. SANCO/10684/2009, thus fulfilling the EC point system requirement for identification of contaminants in samples. The method was validated with a variety of food samples. Calibration curves were linear and covered from 1 to 800 μg kg−1 in the sample for all target compounds. Average recoveries, measured at mass fractions of 10 and 100 μg kg−1 for pyrethroids and 5 and 50 μg kg−1 for dithiocarbamate metabolites, were in the range of 70–120% for all target compounds with relative standard deviations below 20%. Method limits of quantification (MLOQ) were 10 μg kg−1 and 5 μg kg−1 for pyrethroids and dithiocarbamate metabolites, respectively. The method has been successfully applied to the analysis of 600 food samples in the course of the first Hong Kong total diet study with pyrethroids and metabolites of Dithiocarbamates being the pesticides determined.
Claudiu T Supuran - One of the best experts on this subject based on the ideXlab platform.
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Dithiocarbamates strongly inhibit the β class carbonic anhydrases from mycobacterium tuberculosis
Journal of Enzyme Inhibition and Medicinal Chemistry, 2013Co-Authors: Alfonso Maresca, Fabrizio Carta, Daniela Vullo, Claudiu T SupuranAbstract:A series of N-mono- and N,N-disubstituted Dithiocarbamates have been investigated as inhibitors of two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogen Mycobacterium tuberculosis, mtCA 1 (Rv1284) and mtCA 3 (Rv3273). Both enzymes were inhibited with efficacies between the subnanomolar to the micromolar one, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. Aryl, arylalkyl-, heterocyclic as well as aliphatic and amino acyl such moieties led to potent mtCA 1 and 3 inhibitors in both the N-mono- and N,N-disubstituted dithiocarbamate series. This new class of β-CA inhibitors may have the potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug/extensive multi-drug resistance.
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Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo
Journal of Medicinal Chemistry, 2012Co-Authors: Fabrizio Carta, Mayank Aggarwal, Alfonso Maresca, Andrea Scozzafava, Robert Mckenna, Emanuela Masini, Claudiu T SupuranAbstract:A series of Dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some Dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma.
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Dithiocarbamates are strong inhibitors of the beta class fungal carbonic anhydrases from cryptococcus neoformans candida albicans and candida glabrata
Bioorganic & Medicinal Chemistry Letters, 2012Co-Authors: Simona Maria Monti, Fabrizio Carta, Alfonso Maresca, Andrea Scozzafava, Francesca Viparelli, Giuseppina De Simone, Fritz A Muhlschlegel, Claudiu T SupuranAbstract:Abstract A series of N -mono- and N , N -disubstituted Dithiocarbamates have been investigated as inhibitors of three β-carbonic anhydrases (CAs, EC 4.2.1.1) from the fungal pathogens Cryptococcus neoformans , Candida albicans and Candida glabrata , that is, Can2, CaNce103 and CgNce103, respectively. These enzymes were inhibited with efficacies between the subnanomolar to the micromolar range, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. This new class of β-CA inhibitors may have the potential for developing antifungal agents with a diverse mechanism of action compared to the clinically used drugs for which drug resistance was reported, and may also explain the efficacy of Dithiocarbamates as agricultural antifungal agents.
Hitoshi Kamada - One of the best experts on this subject based on the ideXlab platform.
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the origin of an epr signal observed in dithiocarbamate loaded tissues copper ii dithiocarbamate complexes account for the narrow hyperfine lines
Biochimica et Biophysica Acta, 1997Co-Authors: Yasuhiro Suzuki, Satoshi Fujii, Teiji Tominaga, Takashi Yoshimoto, Tetsuhiko Yoshimura, Hitoshi KamadaAbstract:Abstract We examined the electron paramagnetic resonance spectra of some copper(II)-dithiocarbamate complexes in various media at liquid nitrogen temperature. It is demonstrated that Cu(II)-dithiocarbamate complexes exhibit atypical spectra with narrow hyperfine splitting, and that the dithocarbamates forming a water-insoluble Cu(II) complex are permeable in tissues, while those yielding water-soluble complexes are not.
Fabrizio Carta - One of the best experts on this subject based on the ideXlab platform.
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Dithiocarbamates strongly inhibit the β class carbonic anhydrases from mycobacterium tuberculosis
Journal of Enzyme Inhibition and Medicinal Chemistry, 2013Co-Authors: Alfonso Maresca, Fabrizio Carta, Daniela Vullo, Claudiu T SupuranAbstract:A series of N-mono- and N,N-disubstituted Dithiocarbamates have been investigated as inhibitors of two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogen Mycobacterium tuberculosis, mtCA 1 (Rv1284) and mtCA 3 (Rv3273). Both enzymes were inhibited with efficacies between the subnanomolar to the micromolar one, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. Aryl, arylalkyl-, heterocyclic as well as aliphatic and amino acyl such moieties led to potent mtCA 1 and 3 inhibitors in both the N-mono- and N,N-disubstituted dithiocarbamate series. This new class of β-CA inhibitors may have the potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug/extensive multi-drug resistance.
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Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo
Journal of Medicinal Chemistry, 2012Co-Authors: Fabrizio Carta, Mayank Aggarwal, Alfonso Maresca, Andrea Scozzafava, Robert Mckenna, Emanuela Masini, Claudiu T SupuranAbstract:A series of Dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some Dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma.
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Dithiocarbamates are strong inhibitors of the beta class fungal carbonic anhydrases from cryptococcus neoformans candida albicans and candida glabrata
Bioorganic & Medicinal Chemistry Letters, 2012Co-Authors: Simona Maria Monti, Fabrizio Carta, Alfonso Maresca, Andrea Scozzafava, Francesca Viparelli, Giuseppina De Simone, Fritz A Muhlschlegel, Claudiu T SupuranAbstract:Abstract A series of N -mono- and N , N -disubstituted Dithiocarbamates have been investigated as inhibitors of three β-carbonic anhydrases (CAs, EC 4.2.1.1) from the fungal pathogens Cryptococcus neoformans , Candida albicans and Candida glabrata , that is, Can2, CaNce103 and CgNce103, respectively. These enzymes were inhibited with efficacies between the subnanomolar to the micromolar range, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. This new class of β-CA inhibitors may have the potential for developing antifungal agents with a diverse mechanism of action compared to the clinically used drugs for which drug resistance was reported, and may also explain the efficacy of Dithiocarbamates as agricultural antifungal agents.
Alfonso Maresca - One of the best experts on this subject based on the ideXlab platform.
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Dithiocarbamates strongly inhibit the β class carbonic anhydrases from mycobacterium tuberculosis
Journal of Enzyme Inhibition and Medicinal Chemistry, 2013Co-Authors: Alfonso Maresca, Fabrizio Carta, Daniela Vullo, Claudiu T SupuranAbstract:A series of N-mono- and N,N-disubstituted Dithiocarbamates have been investigated as inhibitors of two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogen Mycobacterium tuberculosis, mtCA 1 (Rv1284) and mtCA 3 (Rv3273). Both enzymes were inhibited with efficacies between the subnanomolar to the micromolar one, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. Aryl, arylalkyl-, heterocyclic as well as aliphatic and amino acyl such moieties led to potent mtCA 1 and 3 inhibitors in both the N-mono- and N,N-disubstituted dithiocarbamate series. This new class of β-CA inhibitors may have the potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug/extensive multi-drug resistance.
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Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo
Journal of Medicinal Chemistry, 2012Co-Authors: Fabrizio Carta, Mayank Aggarwal, Alfonso Maresca, Andrea Scozzafava, Robert Mckenna, Emanuela Masini, Claudiu T SupuranAbstract:A series of Dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some Dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma.
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Dithiocarbamates are strong inhibitors of the beta class fungal carbonic anhydrases from cryptococcus neoformans candida albicans and candida glabrata
Bioorganic & Medicinal Chemistry Letters, 2012Co-Authors: Simona Maria Monti, Fabrizio Carta, Alfonso Maresca, Andrea Scozzafava, Francesca Viparelli, Giuseppina De Simone, Fritz A Muhlschlegel, Claudiu T SupuranAbstract:Abstract A series of N -mono- and N , N -disubstituted Dithiocarbamates have been investigated as inhibitors of three β-carbonic anhydrases (CAs, EC 4.2.1.1) from the fungal pathogens Cryptococcus neoformans , Candida albicans and Candida glabrata , that is, Can2, CaNce103 and CgNce103, respectively. These enzymes were inhibited with efficacies between the subnanomolar to the micromolar range, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. This new class of β-CA inhibitors may have the potential for developing antifungal agents with a diverse mechanism of action compared to the clinically used drugs for which drug resistance was reported, and may also explain the efficacy of Dithiocarbamates as agricultural antifungal agents.