The Experts below are selected from a list of 36255 Experts worldwide ranked by ideXlab platform
Silas G Villasboas - One of the best experts on this subject based on the ideXlab platform.
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Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography mass spectrometry
Nature Protocols, 2010Co-Authors: Kathleen F Smart, Raphael B M Aggio, Jeremy Van Houtte, Silas G VillasboasAbstract:This protocol describes an Analytical Platform for the analysis of intra- and extracellular metabolites of microbial cells (yeast, filamentous fungi and bacteria) using gas chromatography-mass spectrometry (GC-MS). The protocol is subdivided into sampling, sample preparation, chemical derivatization of metabolites, GC-MS analysis and data processing and analysis. This protocol uses two robust quenching methods for microbial cultures, the first of which, cold glycerol-saline quenching, causes reduced leakage of intracellular metabolites, thus allowing a more reliable separation of intra- and extracellular metabolites with simultaneous stopping of cell metabolism. The second, fast filtration, is specifically designed for quenching filamentous micro-organisms. These sampling techniques are combined with an easy sample-preparation procedure and a fast chemical derivatization reaction using methyl chloroformate. This reaction takes place at room temperature, in aqueous medium, and is less prone to matrix effect compared with other derivatizations. This protocol takes an average of 10 d to complete and enables the simultaneous analysis of hundreds of metabolites from the central carbon metabolism (amino and nonamino organic acids, phosphorylated organic acids and fatty acid intermediates) using an in-house MS library and a data analysis pipeline consisting of two free software programs (Automated Mass Deconvolution and Identification System (AMDIS) and R).
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Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography mass spectrometry
Nature Protocols, 2010Co-Authors: Kathleen F Smart, Raphael B M Aggio, Jeremy Van Houtte, Silas G VillasboasAbstract:Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography–mass spectrometry
Diego Ballesterosvivas - One of the best experts on this subject based on the ideXlab platform.
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a multi Analytical Platform based on pressurized liquid extraction in vitro assays and liquid chromatography gas chromatography coupled to high resolution mass spectrometry for food by products valorisation part 1 withanolides rich fractions from gol
Journal of Chromatography A, 2019Co-Authors: Diego Ballesterosvivas, Gerardo Alvarezrivera, A P Sanchezcamargo, Elena Ibanez, Fabian Paradaalfonso, Alejandro CifuentesAbstract:Abstract In this work, a multi-Analytical Platform that allows obtaining and characterizing high-added value compounds from natural sources is presented, with a huge potential in traditional medicine, natural products characterization, functional foods, etc. Namely, the proposed multi-Analytical Platform is based on the combination of pressurized liquid extraction (PLE), liquid chromatography (LC) and gas chromatography quadrupole time-of-flight mass spectrometry GC-q-TOF-MS(/MS), in vitro assays and modelling tools for guiding extraction optimization. As case study, goldenberry or cape gooseberry fruit (Physalys peruviana L.) was selected. In particular, the potential of P. peruviana calyces, an important by-product of goldenberry processing, as promising source of bioactive compounds was evaluated. Selection of the most suitable solvent for PLE was based on the Hansen solubility parameters (HSP) approach using 4β-hydroxywithanolide E (4βHWE) and withanolide E (WE) as target compounds due to their bioactive potential. A surface response methodology was further applied for the optimization of the PLE parameters: temperature (50, 100 and 150 °C) and solvent composition (% EtOH in the mixture EtOH/EtOAc). The effects of the independent variables on extraction yield, withanolides content (4βHWE and WE), total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activity (EC50 and TEAC) were evaluated in order to obtain withanolide-rich extracts from P. peruviana calyces. The extract obtained under optimal conditions (at 125 °C and 75% EtOH v/v) exhibited satisfactory extraction yield (14.7%) and moderate antioxidant activity (with an EC50 value of 77.18 μg mL−1 and 1.08 mM trolox g−1), with 4βHWE and WE concentrations of 8.8 and 2.3 mg g−1, respectively. LC-q-TOF-MS/MS analysis of the extract allowed the quantitation of 4βHWE and WE and the tentative identification of several other withanolides structures. The obtained results demonstrate the great potential of this multi-Analytical approach for developing valorisation strategies of food by-products under sustainable conditions, to obtain bioactive-enriched extracts with potential medicinal or health-promoting properties.
Kathleen F Smart - One of the best experts on this subject based on the ideXlab platform.
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Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography mass spectrometry
Nature Protocols, 2010Co-Authors: Kathleen F Smart, Raphael B M Aggio, Jeremy Van Houtte, Silas G VillasboasAbstract:This protocol describes an Analytical Platform for the analysis of intra- and extracellular metabolites of microbial cells (yeast, filamentous fungi and bacteria) using gas chromatography-mass spectrometry (GC-MS). The protocol is subdivided into sampling, sample preparation, chemical derivatization of metabolites, GC-MS analysis and data processing and analysis. This protocol uses two robust quenching methods for microbial cultures, the first of which, cold glycerol-saline quenching, causes reduced leakage of intracellular metabolites, thus allowing a more reliable separation of intra- and extracellular metabolites with simultaneous stopping of cell metabolism. The second, fast filtration, is specifically designed for quenching filamentous micro-organisms. These sampling techniques are combined with an easy sample-preparation procedure and a fast chemical derivatization reaction using methyl chloroformate. This reaction takes place at room temperature, in aqueous medium, and is less prone to matrix effect compared with other derivatizations. This protocol takes an average of 10 d to complete and enables the simultaneous analysis of hundreds of metabolites from the central carbon metabolism (amino and nonamino organic acids, phosphorylated organic acids and fatty acid intermediates) using an in-house MS library and a data analysis pipeline consisting of two free software programs (Automated Mass Deconvolution and Identification System (AMDIS) and R).
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Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography mass spectrometry
Nature Protocols, 2010Co-Authors: Kathleen F Smart, Raphael B M Aggio, Jeremy Van Houtte, Silas G VillasboasAbstract:Analytical Platform for metabolome analysis of microbial cells using methyl chloroformate derivatization followed by gas chromatography–mass spectrometry
Dan Staerk - One of the best experts on this subject based on the ideXlab platform.
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high resolution α amylase assay combined with high performance liquid chromatography solid phase extraction nuclear magnetic resonance spectroscopy for expedited identification of α amylase inhibitors proof of concept and α amylase inhibitor in cinnamon
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Leyla Okutan, Kenneth T Kongstad, Anna K Jager, Dan StaerkAbstract:Type 2 diabetes affects millions of people worldwide, and new improved drugs or functional foods containing selective α-amylase inhibitors are needed for improved management of blood glucose. In this article the development of a microplate-based high-resolution α-amylase inhibition assay with direct photometric measurement of α-amylase activity is described. The inhibition assay is based on porcine pancreatic α-amylase with 2-chloro-4-nitrophenyl-α-d-maltotriose as substrate, which this gives a stable, sensitive, and cheap inhibition assay as requested for high-resolution purposes. In combination with HPLC–HRMS–SPE–NMR, this provides an Analytical Platform that allows simultaneous chemical and biological profiling of α-amylase inhibitors in plant extracts. Proof-of-concept with an artificial mixture of six compounds—of which three are known α-amylase inhibitors—showed that the high-resolution α-amylase inhibition profiles allowed detection of sub-microgram amounts of the α-amylase inhibitors. Furthermore,...
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comprehensive analysis of commercial willow bark extracts by new technology Platform combined use of metabolomics high performance liquid chromatography solid phase extraction nuclear magnetic resonance spectroscopy and high resolution radical scavenging assay
Journal of Chromatography A, 2012Co-Authors: Sara Agnolet, Stefanie Wiese, Robert Verpoorte, Dan StaerkAbstract:Here, proof-of-concept of a new Analytical Platform used for the comprehensive analysis of a small set of commercial willow bark products is presented, and compared with a traditional standardization solely based on analysis of salicin and salicin derivatives. The Platform combines principal component analysis (PCA) of two chemical fingerprints, i.e., HPLC and (1)H NMR data, and a pharmacological fingerprint, i.e., high-resolution 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(+)) reduction profile, with targeted identification of constituents of interest by hyphenated HPLC-solid-phase extraction-tube transfer NMR, i.e., HPLC-SPE-ttNMR. Score plots from PCA of HPLC and (1)H NMR fingerprints showed the same distinct grouping of preparations formulated as capsules of Salix alba bark and separation of S. alba cortex. Loading plots revealed this to be due to high amount of salicin in capsules and ampelopsin, taxifolin, 7-O-methyltaxifolin-3'-O-glucoside, and 7-O-methyltaxifolin in S. alba cortex, respectively. PCA of high-resolution radical scavenging profiles revealed clear separation of preparations along principal component 1 due to the major radical scavengers (+)-catechin and ampelopsin. The new Analytical Platform allowed identification of 16 compounds in commercial willow bark extracts, and identification of ampelopsin, taxifolin, 7-O-methyltaxifolin-3'-O-glucoside, and 7-O-methyltaxifolin in S. alba bark extract is reported for the first time. The detection of the novel compound, ethyl 1-hydroxy-6-oxocyclohex-2-enecarboxylate, is also described.
Alejandro Cifuentes - One of the best experts on this subject based on the ideXlab platform.
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a multi Analytical Platform based on pressurized liquid extraction in vitro assays and liquid chromatography gas chromatography coupled to high resolution mass spectrometry for food by products valorisation part 1 withanolides rich fractions from gol
Journal of Chromatography A, 2019Co-Authors: Diego Ballesterosvivas, Gerardo Alvarezrivera, A P Sanchezcamargo, Elena Ibanez, Fabian Paradaalfonso, Alejandro CifuentesAbstract:Abstract In this work, a multi-Analytical Platform that allows obtaining and characterizing high-added value compounds from natural sources is presented, with a huge potential in traditional medicine, natural products characterization, functional foods, etc. Namely, the proposed multi-Analytical Platform is based on the combination of pressurized liquid extraction (PLE), liquid chromatography (LC) and gas chromatography quadrupole time-of-flight mass spectrometry GC-q-TOF-MS(/MS), in vitro assays and modelling tools for guiding extraction optimization. As case study, goldenberry or cape gooseberry fruit (Physalys peruviana L.) was selected. In particular, the potential of P. peruviana calyces, an important by-product of goldenberry processing, as promising source of bioactive compounds was evaluated. Selection of the most suitable solvent for PLE was based on the Hansen solubility parameters (HSP) approach using 4β-hydroxywithanolide E (4βHWE) and withanolide E (WE) as target compounds due to their bioactive potential. A surface response methodology was further applied for the optimization of the PLE parameters: temperature (50, 100 and 150 °C) and solvent composition (% EtOH in the mixture EtOH/EtOAc). The effects of the independent variables on extraction yield, withanolides content (4βHWE and WE), total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activity (EC50 and TEAC) were evaluated in order to obtain withanolide-rich extracts from P. peruviana calyces. The extract obtained under optimal conditions (at 125 °C and 75% EtOH v/v) exhibited satisfactory extraction yield (14.7%) and moderate antioxidant activity (with an EC50 value of 77.18 μg mL−1 and 1.08 mM trolox g−1), with 4βHWE and WE concentrations of 8.8 and 2.3 mg g−1, respectively. LC-q-TOF-MS/MS analysis of the extract allowed the quantitation of 4βHWE and WE and the tentative identification of several other withanolides structures. The obtained results demonstrate the great potential of this multi-Analytical approach for developing valorisation strategies of food by-products under sustainable conditions, to obtain bioactive-enriched extracts with potential medicinal or health-promoting properties.