Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Regul Toxicol Pharmacol ; 80: 91-101, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27311683

RESUMEN

The impact of the Tobacco Heating System 2.2 (THS 2.2) on indoor air quality was evaluated in an environmentally controlled room using ventilation conditions recommended for simulating "Office", "Residential" and "Hospitality" environments and was compared with smoking a lit-end cigarette (Marlboro Gold) under identical experimental conditions. The concentrations of eighteen indoor air constituents (respirable suspended particles (RSP) < 2.5 µm in diameter), ultraviolet particulate matter (UVPM), fluorescent particulate matter (FPM), solanesol, 3-ethenylpyridine, nicotine, 1,3-butadiene, acrylonitrile, benzene, isoprene, toluene, acetaldehyde, acrolein, crotonaldehyde, formaldehyde, carbon monoxide, nitrogen oxide, and combined oxides of nitrogen) were measured. In simulations evaluating THS 2.2, the concentrations of most studied analytes did not exceed the background concentrations determined when non-smoking panelists were present in the environmentally controlled room under equivalent conditions. Only acetaldehyde and nicotine concentrations were increased above background concentrations in the "Office" (3.65 and 1.10 µg/m(3)), "Residential" (5.09 and 1.81 µg/m(3)) and "Hospitality" (1.40 and 0.66 µg/m(3)) simulations, respectively. Smoking Marlboro Gold resulted in greater increases in the concentrations of acetaldehyde (58.8, 83.8 and 33.1 µg/m(3)) and nicotine (34.7, 29.1 and 34.6 µg/m(3)) as well as all other measured indoor air constituents in the "Office", "Residential" and "Hospitality" simulations, respectively.


Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Contaminación del Aire Interior/efectos adversos , Equipos y Suministros Eléctricos , Monitoreo del Ambiente/métodos , Exposición por Inhalación/efectos adversos , Fumar/efectos adversos , Contaminación por Humo de Tabaco/efectos adversos , Adulto , Ambiente Controlado , Diseño de Equipo , Calor , Humanos , Persona de Mediana Edad , Medición de Riesgo , Adulto Joven
2.
J Am Soc Mass Spectrom ; 35(6): 1261-1271, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38780179

RESUMEN

We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (H3O+). Nevertheless, specific ions generated by glycerin (m/z 93.055) and propylene glycol (m/z 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in H3O+ mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the H3O+ reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (m/z 94.086) and acetone (m/z 76.076) mixtures. Concerning the nitric oxide mode, specific m/z were identified for acetaldehyde (m/z 43.018), acetone (m/z 88.039), glycidol (m/z 73.028), and propylene glycol (m/z 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.


Asunto(s)
Sistemas Electrónicos de Liberación de Nicotina , Espectrometría de Masas , Nicotiana , Compuestos Orgánicos Volátiles , Espectrometría de Masas/métodos , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/química , Nicotiana/química , Propilenglicol/análisis , Propilenglicol/química , Acetaldehído/análisis , Acetaldehído/química , Acetona/análisis , Acetona/química , Acetona/análogos & derivados , Glicerol/análisis , Glicerol/química , Calor , Compuestos Epoxi/química , Compuestos Epoxi/análisis , Propanoles/química , Propanoles/análisis
3.
Environ Pollut ; 257: 113518, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31753636

RESUMEN

There is growing evidence that the very presence of human beings in an enclosed environment can impact air quality by affecting the concentrations of certain airborne volatile organic compounds (VOC). This influence increases considerably when humans perform different activities, such as using toiletries, or simply eating and drinking. To understand the influence of these parameters on the concentrations of selected airborne constituents, a study was performed under simulated residential conditions in an environmentally-controlled exposure room. The human subjects either simply remained for a certain time in the exposure room, or performed pre-defined activities in the room (drinking wine, doing sport, using toiletries, and preparation of a meal containing melted cheese). The impact of each activity was assessed separately using our analytical platform and exposure room under controlled environmental conditions. The results showed that prolonged human presence leads to increased levels of isoprene, TVOCs, formaldehyde and, to a lesser extent, acetaldehyde. These outcomes were further supported by results of meta-analyses of data acquired during several internal studies performed over two years. Furthermore, it was seen that the indoor concentrations of several of the selected constituents rose when the recreational and daily living activities were performed. Indeed, an increase in acetaldehyde was observed for all tested conditions, and these higher indoor levels were especially notable during wine-drinking as well as cheese meal preparation. Formaldehyde increased during the sessions involving sport, using toiletries, and cheese meal preparation. Like acetaldehyde, acrolein, crotonaldehyde and particulate matter levels rose significantly during the cheese meal preparation session. In conclusion, prolonged human residence indoors and some recreational and daily living activities caused substantial emissions of several airborne pollutants under ventilation typical for residential environments.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Acetaldehído/análisis , Contaminación del Aire/análisis , Contaminación del Aire Interior/análisis , Contaminación del Aire Interior/estadística & datos numéricos , Aldehídos , Butadienos , Exposición a Riesgos Ambientales/análisis , Formaldehído/análisis , Hemiterpenos , Vivienda , Humanos , Material Particulado/análisis , Ventilación , Compuestos Orgánicos Volátiles/análisis
4.
J Nat Prod ; 72(3): 477-9, 2009 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-19323568

RESUMEN

Fermentation of a Penicillium sp. isolated from a surface-sterilized thallus segment of the brown alga Xiphophora gladiata, collected from Macrocarpa Point, Otago, New Zealand, in half-strength potato dextrose broth led to the isolation and characterization of three alkaloids: the known N-hydroxy-2-pyridone, PF1140 (1), and two new 2-pyridones, 2 and 3.


Asunto(s)
Alcaloides/aislamiento & purificación , Penicillium/química , Piridonas/aislamiento & purificación , Alcaloides/química , Animales , Benzopiranos/química , Benzopiranos/aislamiento & purificación , Leucemia P388 , Biología Marina , Ratones , Estructura Molecular , Nueva Zelanda , Phaeophyceae/microbiología , Piridonas/química , Relación Estructura-Actividad
5.
J Org Chem ; 73(21): 8635-8, 2008 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-18841911

RESUMEN

Biosynthetic studies on spiro-mamakone A (1), a potently cytotoxic and antimicrobial compound from an endophytic fungus isolated from the New Zealand native tree Knightia excelsa (rewarewa), confirm the polyketide origins of this unique compound belonging to the spirobisnaphthalene class of compounds. The biosynthesis proceeds via an unprecedented symmetric enedione with the two halves of the molecule being formed from two separate pentaketide units connected by oxidative coupling.


Asunto(s)
Hongos/metabolismo , Naftalenos , Compuestos de Espiro , Acetales , Antiinfecciosos , Macrólidos/química , Naftalenos/química , Naftalenos/metabolismo , Compuestos de Espiro/química , Compuestos de Espiro/metabolismo
6.
J Nat Prod ; 71(9): 1595-9, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18710284

RESUMEN

The use of an HPLC bioactivity profiling/microtiter plate technique in conjunction with capillary probe NMR instrumentation and access to appropriate databases effectively short-circuits conventional dereplication procedures, necessarily based on multimilligram extracts, to a single, more rapid submilligram operation. This approach to dereplication is illustrated using fungal or bacterial extracts that contain known compounds. In each case the dereplication steps were carried out on microgram quantities of extract and demonstrate the discriminating power of (1)H NMR spectroscopy as a definitive dereplication tool.


Asunto(s)
Productos Biológicos/química , Técnicas Químicas Combinatorias/métodos , Extractos Vegetales/química , Cromatografía Líquida de Alta Presión , Técnicas Químicas Combinatorias/economía , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular
7.
J Nat Prod ; 71(9): 1600-3, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18702471

RESUMEN

By the application of an HPLC bioactivity profiling/microtiter technique in conjunction with capillary NMR instrumentation and access to the AntiMarin database the conventional evaluation/isolation dereplication/characterization procedures can be dramatically truncated. This approach is illustrated using the isolation of a new peptaibol, chrysaibol (1), from a New Zealand isolate of the mycoparasitic fungus Sepedonium chrysospermum. The unique nature of chrysaibol was recognized by bioactivity-guided fractionation using HPLC bioactivity profiling/microtiter plate analysis in conjunction with capillary NMR instrumentation and the AntiMarin database. 2D NMR techniques, in combination with MS fragmentation experiments, determined the planar structure of chrysaibol (1), while the absolute configurations of the amino acid residues were defined by Marfey's method. Chrysaibol (1) was cytotoxic against the P388 murine leukemia cell line (IC50 6.61 microM) and showed notable activity against Bacillus subtilis (IC50 1.54 microM).


Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Hypocreales/química , Animales , Antibacterianos/química , Bacillus subtilis/efectos de los fármacos , Productos Biológicos/química , Ensayos de Selección de Medicamentos Antitumorales , Leucemia P388 , Ratones , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Nueva Zelanda , Peptaiboles
8.
J Chromatogr A ; 1580: 90-99, 2018 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-30391037

RESUMEN

A sensitive and accurate method for the quantification of 1'-Demethyl-1'-nitrosonicotine (NNN) and 4-(methylnitrosamino)-1-(3-Pyridyl)-1-butanone (NNK) in indoor air was developed and validated. To this aim, a novel approach for the collection of two tobacco-specific nitrosamines, using silica sorbent cartridges followed by simplified sample preparation and isotope dilution liquid chromatography/electrospray ionization tandem mass spectrometry, was applied. This procedure led to a substantial improvement in terms of sensitivity and sample throughput as compared with methods using conventional trapping. For the validation, a matrix-based approach using an accuracy profile procedure was selected. The evaluated matrices were background air samples, environmental aerosols of a heat-not-burn tobacco product (Tobacco Heating System [THS] 2.2, commercialized under the brand IQOS®), a rechargeable electronic cigarette (Solaris®), and the environmental tobacco smoke (ETS) of a conventional cigarette (Marlboro Gold®). The method showed excellent recoveries, sensitivity, and precision. The limits of detection of the method for NNN and NNK were 0.0108 ng/m3 and 0.0136 ng/m3, respectively. The calibration range of the instrument spanned 0.2-60 ng/mL. The calculated lower working range limit (LWRL) of the method for NNN was 0.126 ng/m3, and the LWRL for NNK was 0.195 ng/m3. The method was applied to evaluate surrogate environmental aerosols generated using smoking machines. This model is reliable but gives a large overestimation of the possible impact of THS 2.2 and e-cigarettes on indoor air, because the retention of NNN and NNK in the body of the consumers is not taken into account. As a consequence, the values reported do not reflect a real-life setting. The contents of the two target compounds in the surrogate environmental aerosols were 0.0830 ±â€¯0.0153 ng/m3 of NNN and 0.0653 ±â€¯0.0138 ng/m3 of NNK for THS 2.2, 0.0561 ±â€¯0.0296 ng/m3 of NNN for e-cigarettes, and 0.816 ±â€¯0.109 ng/m3 of NNN and 4.13 ±â€¯1.04 ng/m3 NNK for cigarettes. These values correspond to 10% of the measured ETS concentration for NNN in environmental aerosols of THS 2.2 and 7% for those of e-cigarettes. For NNK, the value for the environmental aerosol of THS 2.2 was 2% of the ETS value.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Monitoreo del Ambiente/métodos , Nicotiana/química , Nitrosaminas/análisis , Carcinógenos/análisis , Cromatografía Liquida , Sistemas Electrónicos de Liberación de Nicotina , Fumar , Productos de Tabaco/análisis
9.
Talanta ; 158: 165-178, 2016 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-27343591

RESUMEN

Studies in environmentally controlled rooms have been used over the years to assess the impact of environmental tobacco smoke on indoor air quality. As new tobacco products are developed, it is important to determine their impact on air quality when used indoors. Before such an assessment can take place it is essential that the analytical methods used to assess indoor air quality are validated and shown to be fit for their intended purpose. Consequently, for this assessment, an environmentally controlled room was built and seven analytical methods, representing eighteen analytes, were validated. The validations were carried out with smoking machines using a matrix-based approach applying the accuracy profile procedure. The performances of the methods were compared for all three matrices under investigation: background air samples, the environmental aerosol of Tobacco Heating System THS 2.2, a heat-not-burn tobacco product developed by Philip Morris International, and the environmental tobacco smoke of a cigarette. The environmental aerosol generated by the THS 2.2 device did not have any appreciable impact on the performances of the methods. The comparison between the background and THS 2.2 environmental aerosol samples generated by smoking machines showed that only five compounds were higher when THS 2.2 was used in the environmentally controlled room. Regarding environmental tobacco smoke from cigarettes, the yields of all analytes were clearly above those obtained with the other two air sample types.


Asunto(s)
Contaminación del Aire Interior/análisis , Calor , Nicotiana , Contaminación por Humo de Tabaco/análisis , Contaminantes Atmosféricos/análisis , Nicotina/análisis , Material Particulado/análisis , Piridinas/análisis , Productos de Tabaco , Compuestos Orgánicos Volátiles/análisis
10.
J Nat Prod ; 71(5): 824-7, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18396903

RESUMEN

Subinhibitory concentrations of antibiotics were found to enhance and modulate the production of new phenazines, streptophenazines A-H, in a marine Streptomyces isolate. The streptophenazines differ in length and substitution of an alkyl chain. The pattern of metabolites formed depends on the antibiotic used. In the presence of tetracycline, streptophenazines F and G were induced and the production of streptophenazines A-D was increased. When using bacitracin, mainly streptophenazine H was produced. Streptophenazines C and H showed moderate activity against Bacillus subtilis, while streptophenazine C was also active against Staphylococcus lentus.


Asunto(s)
Antibacterianos/análisis , Antibacterianos/farmacología , Fenazinas/aislamiento & purificación , Streptomyces/química , Bacillus subtilis/efectos de los fármacos , Candida glabrata/efectos de los fármacos , Biología Marina , Pruebas de Sensibilidad Microbiana , Fenazinas/química , Fenazinas/metabolismo , Staphylococcus/efectos de los fármacos
11.
J Nat Prod ; 71(5): 806-9, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18416579

RESUMEN

The full stereochemical characterization of 4-methylproline, a rare amino acid found in a number of peptidic secondary metabolites, has often been hindered by long reaction sequences or low stereoselectivity in the synthesis leading to reference samples. The preparation of the four diastereoisomers of 4-methylproline by a concise and stereoselective route is presented and features a six-step route with late-stage stereodivergence, good stereoselectivity for both cis- and trans-series (75% and 88% de, respectively), and good overall yields (cumulative yields of 30-40%). Additional data on the Marfey's derivatives of the stereoisomers are also presented.


Asunto(s)
Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Prolina/análogos & derivados , Prolina/síntesis química , Prolina/química , Estereoisomerismo
12.
J Nat Prod ; 69(10): 1481-4, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17067166

RESUMEN

A new cyclic pentapeptide, chrysosporide (1), was isolated from a New Zealand sample of the mycoparasitic fungus Sepedonium chrysospermum by bioactivity-guided fractionation. The planar structure was deduced by detailed spectroscopic analysis, and the absolute configurations of the amino acid residues were defined by Marfey's method. As both enantiomers of Leu occurred in chrysosporide, molecular mechanics calculations were applied to the analysis to distinguish between the possible structural isomers. Only the lowest energy conformers of the cyclo-(L-Val-D-Ala-L-Leu-L-Leu-D-Leu) isomer were in agreement with the observed NOEs, suggesting that this was the most probable amino acid sequence for chrysosporide (1).


Asunto(s)
Ascomicetos/química , Péptidos Cíclicos/química , Péptidos Cíclicos/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Cristalografía por Rayos X , Ensayos de Selección de Medicamentos Antitumorales , Leucemia P388 , Ratones , Modelos Químicos , Estructura Molecular , Nueva Zelanda , Péptidos Cíclicos/farmacología , Conformación Proteica , Estereoisomerismo
13.
J Org Chem ; 71(2): 492-7, 2006 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-16408955

RESUMEN

[reaction: see text] Cladobotric acids A-F (1-6), fungal-derived polyketides, were isolated from the fermentation broth of a New Zealand Cladobotryum species. Structures were determined by extensive spectral analysis and X-ray crystallography, and the polyketide origin of 1-6 was concluded from feeding experiments with (13)C-labeled precursors. The observed folding pattern for the polyketide chain is unusual for fungi. Cladobotric acids A-F (1-6) exhibited notable cytotoxicity against the murine P388 leukemia cell line and were also active against Bacillus subtilis and Candida albicans.


Asunto(s)
Antineoplásicos/química , Botrytis/química , Animales , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Botrytis/aislamiento & purificación , Leucemia P388 , Espectroscopía de Resonancia Magnética , Ratones , Modelos Moleculares , Conformación Molecular , Nueva Zelanda
14.
J Nat Prod ; 69(10): 1389-93, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17067148

RESUMEN

Six new linear peptides, pterulamides I-VI (1-6), were isolated from the fruiting bodies of a Malaysian Pterula species. The structures were elucidated by MS and 2D NMR experiments, and the absolute configurations of the constituent amino acids established using Marfey's method. The pterulamides are mainly assembled from nonpolar N-methylated amino acids and, most interestingly, have non-amino-acid N-terminal groups, among them the unusual cinnamoyl, (E)-3-methylsulfinylpropenoyl, and (E)-3-methylthiopropenoyl groups. Furthermore, pterulamides I-V are the first natural peptides with a methylamide C-terminus. Pterulamides I and IV are cytotoxic against the P388 cell line with IC50 values of 0.55 and 0.95 microg/mL (0.79 and 1.33 microM), respectively.


Asunto(s)
Antineoplásicos , Basidiomycota/química , Oligopéptidos , Animales , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Leucemia P388 , Malasia , Ratones , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Oligopéptidos/química , Oligopéptidos/aislamiento & purificación , Oligopéptidos/farmacología
15.
J Org Chem ; 71(21): 7947-51, 2006 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-17025281

RESUMEN

Four new cyclodepsipeptides, pteratides I-IV (1-4), have been isolated from the extract of a Pterula species collected from a Malaysian tropical forest. Homonuclear and heteronuclear 2D NMR techniques as well as MS fragmentation experiments, in combination with methanolysis, determined the gross structures of the peptides and showed that pteratides I and II each contained the nonproteinogenic amino acid 4-methylproline. The absolute configurations of the amino acids in pteratides I-IV were established using Marfey's method. Pteratides I and II are each potently cytotoxic against the P388 murine leukemia cell line (IC50 values of 41 and 40 nM, respectively). Pteratides III and IV show weaker, but still notable, activity with IC50 values of 7.4 and 2.9 microM, respectively.


Asunto(s)
Antineoplásicos/aislamiento & purificación , Basidiomycota/química , Depsipéptidos/química , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Depsipéptidos/aislamiento & purificación , Depsipéptidos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Concentración 50 Inhibidora , Ratones , Estructura Molecular
16.
J Nat Prod ; 69(4): 621-4, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16643039

RESUMEN

Using HPLC/microtiter-plate-based generation of activity profiles the extract of a marine alga-derived fungus, identified as Gliocladium sp., was shown to contain the known strongly cytotoxic metabolite 4-keto-clonostachydiol (1) and also clonostachydiol (2) as well as gliotide (3), a new cyclodepsipeptide containing several D-amino acids. The absolute configuration of 1 was elucidated by reduction to 2, and two further oxidized derivatives of clonostachydiol (5, 6) were prepared and evaluated for biological activity.


Asunto(s)
Antineoplásicos/aislamiento & purificación , Depsipéptidos/aislamiento & purificación , Gliocladium/química , Lactonas/aislamiento & purificación , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Cromatografía Líquida de Alta Presión , Depsipéptidos/química , Depsipéptidos/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Eucariontes , Lactonas/química , Lactonas/farmacología , Leucemia P388 , Biología Marina , Ratones , Estructura Molecular , Nueva Zelanda , Oxidación-Reducción
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA