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1.
Food Chem Toxicol ; 159 Suppl 1: 112711, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34843869

RESUMO

The existing information supports the use of this material as described in this safety assessment. Phenethyl phenylacetate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that phenethyl phenylacetate is not genotoxic. Data provide a calculated MOE >100 for the repeated dose toxicity endpoint. Data on read-across analog benzyl benzoate (CAS # 120-51-4) provide an MOE >100 for the developmental toxicity endpoint. The fertility and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class I material, and the exposure to phenethyl phenylacetate is below the TTC (0.03 mg/kg/day, and 1.4 mg/day, respectively). Data from analog benzyl phenylacetate (CAS # 102-16-9) show that there are no safety concerns for phenethyl phenylacetate for skin sensitization under the current declared levels of use. The phototoxicity/photoallergenicity endpoints were evaluated based on UV/Vis spectra; phenethyl phenylacetate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; phenethyl phenylacetate was found not to be PBT as per the IFRA Environmental Standards and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Assuntos
Acetatos/toxicidade , Exposição Ambiental/efeitos adversos , Odorantes/análise , Perfumes/toxicidade , Fenóis/toxicidade , Fenilacetatos/toxicidade , Segurança , Academias e Institutos/normas , Acetatos/análise , Animais , Dermatite Fotoalérgica , Dermatite Fototóxica , Determinação de Ponto Final , Europa (Continente) , Fertilidade/efeitos dos fármacos , Humanos , Testes de Mutagenicidade , América do Norte , Perfumes/química , Fenóis/análise , Fenilacetatos/análise , Sistema de Registros , Reprodução/efeitos dos fármacos , Sistema Respiratório/efeitos dos fármacos , Medição de Risco , Pele/efeitos dos fármacos , Testes de Toxicidade
2.
J Pharm Biomed Anal ; 179: 112955, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31866139

RESUMO

Vicagrel is a promising novel antiplatelet drug. However, the quantification of vicagrel in plasma is currently unavailable since it is liable to be hydrolyzed in plasma by esterases. In this study, an optimized strategy was developed and validated to stabilize vicagrel, 2-oxo-clopidogrel (thiolactone metabolite), and H4 (active thiol metabolite) before quantification of the analytes, such as addition of citric acid (for plasma acidification) and NaF (a non-specific esterase inhibitor) to inhibit esterase activity, immediate addition of a thiol-alkylating reagent MPB into blood samples to derivatize H4 for the formation of stable H4 derivative (i.e., MP-H4), use of the anticoagulant K2EDTA to minimize the conversion of 2-oxo-clopidogrel to H-endo, and keeping the analytes at 4 °C or on wet ice to minimize degradation of the analytes when processed and analyzed. The stability was measured as percent of each analyte remained in plasma samples after their storage for 4 h at 4 °C or in blood samples after 1 h at 4 °C. The results indicated that stability of vicagrel was increased significantly in stabilized plasma or blood samples compared with non-stabilized controls for rats and humans, respectively, and that the stability of 2-oxo-clopidogrel was increased to a certain extent. In contrast, MP-H4 formed was stable in plasma immediately after thorough mixture of MPB with blood. We conclude that the above strategy is useful for improving the stability of vicagrel, 2-oxo-clopidogrel, and H4 in rat or human plasma, and that vicagrel and its two major metabolites can be quantified accurately and simultaneously.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Fenilacetatos/análise , Inibidores da Agregação Plaquetária/análise , Espectrometria de Massas em Tandem/métodos , Tiofenos/análise , Animais , Feminino , Humanos , Masculino , Fenilacetatos/farmacocinética , Inibidores da Agregação Plaquetária/farmacocinética , Ratos , Ratos Sprague-Dawley , Manejo de Espécimes , Temperatura , Tiofenos/farmacocinética , Fatores de Tempo
3.
ACS Synth Biol ; 7(12): 2790-2795, 2018 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-30418753

RESUMO

Despite the importance of 2-phenylacetic acid, a plant hormone in the endogenous auxin family, its biosynthesis pathway has yet to be elucidated. In this study, we developed a novel whole-cell biosensor for the simultaneous quantification of 2-phenylacetic acid (PA) and 2-phenylethylamine (PEA) through the regulation of bacterial catabolism of aromatic compounds. We used the PA regulon to enable the recognition of PA and PEA. Differentiation of PEA from PA involves the incorporation of the FeaR regulon within the same whole-cell biosensor to report the presence of aromatic amines. The proposed system is highly sensitive to PA as well as PEA.


Assuntos
Técnicas Biossensoriais/métodos , Escherichia coli/metabolismo , Fenetilaminas/análise , Fenilacetatos/análise , Oxirredutases/genética , Oxirredutases/metabolismo , Plasmídeos/genética , Plasmídeos/metabolismo , Espectrometria de Fluorescência
4.
J Agric Food Chem ; 66(40): 10438-10446, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30227707

RESUMO

Although most of the health effects attributed to polyphenols may be linked to their phenolic-derived metabolites, the role of the intestinal derived-phenolics in human health is still far from being well understood. We determined the profile of fecal phenolic-derived metabolites, microbiota, biomarkers of oxidative stress and inflammation, and daily intake of bioactive compounds in 71 elderly volunteers. Phenylacetic and phenylpropionic acids were the main phenolic metabolites present in feces. From them, phenylacetic acid was related with a more pro-oxidant and immune stimulated status, and both were negatively associated with fecal propionate, whereas phenylpropionic acid was directly related with the fecal concentration of acetate. Moreover, phenylacetic acid was negatively associated with the Bacteroides group and Clostridium cluster XIVa and positively with Lactobacillus. These results provide a rationale to explore the potential of fecal microbial phenolic-derived metabolites as possible biomarkers of health status in future studies focused on the elderly population.


Assuntos
Biomarcadores/análise , Fezes/química , Fenilacetatos/análise , Fenilpropionatos/análise , Idoso , Idoso de 80 Anos ou mais , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biomarcadores/metabolismo , Dieta , Feminino , Microbioma Gastrointestinal , Nível de Saúde , Humanos , Mucosa Intestinal/metabolismo , Intestinos/microbiologia , Masculino , Estresse Oxidativo , Fenilacetatos/metabolismo , Fenilpropionatos/metabolismo
5.
Food Funct ; 9(9): 4858-4864, 2018 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30156246

RESUMO

Tea polyphenols (TP) have many health benefits, but most are metabolized into low molecular-weight phenolic acids after oral administration. In the present study, the absorption, metabolism, and excretion of catechins in rats fed a normal chow diet and in obese rats fed a high-fat and high-sugar (HFHS) diet were compared. After a ten-day oral administration of TP (500 mg per kg bw), the plasma levels of (-)-epigallocatechin gallate (EGCG) and (-)-gallocatechin gallate (GCG) in obese rats were significantly lower than those in the normal group. In obese rats, the fecal levels of EGCG, (-)-epicatechin gallate (ECG) and GCG were significantly enhanced. Ten phenolic metabolites of TP were quantitatively analyzed, and the results showed that 4-hydroxyphenylacetic acid was the primary metabolite in feces and plasma. The plasma and fecal concentrations of 4-hydroxyphenylacetic acid in the obese group were significantly lower than those in normal rats, but the levels of 4-hydroxyphenylpropionic acid in plasma and feces were increased. The content of other phenolic acids was also dramatically changed. These results suggested that a HFHS diet might influence the excretion of tea catechins, leading to insufficient metabolism of catechins by the gut microflora.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Camellia sinensis/química , Suplementos Nutricionais , Obesidade/terapia , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , Polifenóis/uso terapêutico , Animais , Anti-Inflamatórios não Esteroides/análise , Anti-Inflamatórios não Esteroides/metabolismo , Catequina/análogos & derivados , Catequina/análise , Catequina/sangue , Catequina/metabolismo , Fezes/química , Fermentação , Manipulação de Alimentos , Microbioma Gastrointestinal , Absorção Intestinal , Eliminação Intestinal , Masculino , Obesidade/imunologia , Obesidade/metabolismo , Obesidade/microbiologia , Oxirredução , Fenóis/análise , Fenóis/metabolismo , Fenilacetatos/análise , Fenilacetatos/sangue , Fenilacetatos/metabolismo , Polifenóis/análise , Polifenóis/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 204: 260-266, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-29936223

RESUMO

The first spectrofluorimetric report investigating the fluorimetric behavior of the antihistaminic drug, azelastine (AZEL), and the non-steroidal anti-inflammatory drug, nepafenac (NEP), either in bulk or in their dosage forms, eye drops and ophthalmic suspension. After a full investigation of the factors that may influence their spectrofluorimetric behavior: pH, different organized media and organic solvents, the optimum factors were set in order to enable the analysis of each drug with maximum sensitivity. The AZEL spectrofluorimetric analysis was set at 286/364 (λex/λem) in distilled water while for NEP, the analysis was set at 228/303 (λex/λem) in methanol. The linearity range for AZEL was from 0.1 to 1.5 µg/mL while that of NEP was from 0.2 to 1.5 µg/mL. The linearity yielded good regression parameters with low LOD (0.022 and 0.032 µg/mL for AZEL and NEP, respectively) and LOQ (0.073 and 1.08 µg/mL for AZEL and NEP, respectively) when compared with those obtained from many previous spectroscopic and chromatographic reports in literature. The method was ICH validated and was applied to the analysis of AZEL and NEP with good selectivity regarding the inactive ingredients.


Assuntos
Benzenoacetamidas/análise , Soluções Oftálmicas/análise , Fenilacetatos/análise , Ftalazinas/análise , Espectrometria de Fluorescência/métodos , Benzenoacetamidas/química , Estabilidade de Medicamentos , Limite de Detecção , Modelos Lineares , Soluções Oftálmicas/química , Fenilacetatos/química , Ftalazinas/química , Reprodutibilidade dos Testes
7.
Analyst ; 143(9): 2096-2101, 2018 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-29634056

RESUMO

In this study, a novel noncompetitive homogeneous immunoassay for antigen detection was developed. We utilized ß-glucuronidase (GUS), a homotetrameric enzyme, the assembly of all of whose subunits is necessary to attain its activity. By using a mutant GUS (GUSm), wherein the dimerization of dimers, which is a rate-limiting step, can be effectively inhibited by a set of interface mutations, we attempted to create a biosensor for detecting various molecules. Usually, the affinity between the two variable region domains (VH and VL) of an antibody, especially for a small molecule, is relatively low. However, in the presence of an antigen, the affinity increases so that they bind tighter to each other. A pair of fusion proteins, comprising the VH and VL regions of the antibody as the detector tethered to a GUSm subunit as the reporter, was constructed to detect antigen 4-hydroxy-3-nitrophenylacetyl (NP) and bone Gla protein (BGP) through GUS activity measurement. Colorimetric and fluorescence assays could detect NP, 5-iodo-NP, and BGP within 1 h without separation steps and with a higher signal/background ratio than conventional ELISA. The instantaneous response after simple mixing of the components makes this system convenient and high-throughput. The system could be effective for the analyses of various small molecules in environmental and clinical settings.


Assuntos
Antígenos/análise , Técnicas Biossensoriais , Glucuronidase/química , Imunoensaio , Anticorpos , Ensaio de Imunoadsorção Enzimática , Humanos , Nitrofenóis/análise , Osteocalcina/análise , Fenilacetatos/análise
8.
Nat Prod Res ; 32(6): 662-667, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28602098

RESUMO

One new alkaloid, named as acremolin C (1), was isolated from static culture of Antarctic fungus, Aspergillus sydowii SP-1, in an investigation of the antimicrobial constituents of this Antarctic microorganism, and its structure was determined by spectroscopic methods. Additionally, four known compounds, cyclo-(L-Trp-L-Phe) (2), 4-hydroxyphenylacetic acid (3), (7S)-(+)-hydroxysydonic acid (4) and (7S, 11S)-(+)-12-hydroxysydonic acid (5), were isolated and identified. Biological studies disclosed that compounds 2, 4 and 5 showed moderate inhibitions against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) as comparing to tigecycline, while compound 1 displayed weak inhibition activities against MRSA and MRSE.


Assuntos
Alcaloides/química , Alcaloides/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Aspergillus/química , Regiões Antárticas , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Fenilacetatos/análise , Fenilacetatos/farmacologia , Sesquiterpenos/análise , Sesquiterpenos/farmacologia , Staphylococcus epidermidis/efeitos dos fármacos
9.
J Fluoresc ; 27(6): 2195-2200, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28895010

RESUMO

The wide use of pesticide p-fluorophenoxyacetic acid has caused the serious environmental contaminant. A novel fluorescent probe for sensitive detection of p-fluorophenoxyacetic acid in aqueous solutions based on 3.0G quaternary ammonium polyamidoamine (PAMAM) dendrimer modified quantum dots (QDs) (PAMAM@QDs) was reported. Through the solvent-evaporation method, quaternary ammonium PAMAM was employed to modify the QDs. Poloxamer 188 was used to improve the solubility and stability. The resultant PAMAM@QDs dispersed well in water. Fluorescence (FL) spectroscopic study showed that the FL intensity of the PAMAM@QDs was enhanced in the presence of p-fluorophenoxyacetic acid. Under optimal conditions, the enhanced FL intensity as a function of concentration matched very well in the range of 1 ~ 200 µg/mL of p-fluorophenoxyacetic acid, while the lower limits of detection were found to be 0.16 µg/mL. These results show that PAMAM@QDs is a promising luminescent probe for the detection of pesticides.


Assuntos
Dendrímeros/química , Corantes Fluorescentes/química , Hidrocarbonetos Fluorados/análise , Praguicidas/análise , Fenilacetatos/análise , Pontos Quânticos/química , Poluentes Químicos da Água/análise , Fenilacetatos/química
10.
Planta Med ; 83(12-13): 1085-1096, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28403500

RESUMO

Rhizomes of Actaea racemosa L. (formerly Cimicifuga racemosa) gained increasing interest as a plant-derived drug due to its hormone-like activity and the absence of estrogenic activity. According to the Current Good Manufacturing Practices guidelines and pharmacopeial standards, quality assessment of herbal starting materials includes tests on identity and substitution, as well as quantification of secondary metabolites, usually by HPTLC and LC methods. To reduce the laboratory effort, we investigated near-infrared spectroscopy for rapid species authentication and quantification of metabolites of interest.Near-infrared spectroscopy analysis is carried out directly on the milled raw plant material. Spectra were correlated with reference data of polyphenols and triterpene glycosides determined by LC/diode array detection and LC/evaporative light scattering detection, respectively. Quantification models were built and validated by cross-validation procedures. Clone plants, derived by vegetative propagation, and plants of a collection from different geographical origins cultivated in Berlin were analysed together with mixed batches from wild harvests purchased at wholesalers.Generally, good to excellent correlations were found for the overall content of polyphenols with coefficients of determination of R2 > 0.93. For individual polyphenols such as fukinolic acid, only models containing clone plants succeeded (R2 > 0.92). For the total content of triterpene glycosides, results were generally worse in comparison to polyphenols and were observed only for the mixed batches (R2 = 0.93).Next to quantitative analysis, near-infrared spectroscopy was proven as a rapid alternative to other, more laborious methods for species authentication. Near-infrared spectroscopy was able to distinguish different Actaea spp. such as the North American Actaea cordifolia and the Asian Actaea cimicifuga, Actaea dahurica, Actaea heracleifolia, and Actaea simplex.


Assuntos
Cimicifuga/química , Glicosídeos/análise , Polifenóis/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Triterpenos/análise , Ácidos Cafeicos/análise , Ácidos Cafeicos/química , Cromatografia Líquida , Glicosídeos/química , Fenilacetatos/análise , Fenilacetatos/química , Plantas Medicinais , Polifenóis/química , Controle de Qualidade , Rizoma/química , Triterpenos/química
11.
J Agric Food Chem ; 64(33): 6407-15, 2016 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-27529118

RESUMO

Pesticide transport from seed dressings toward subsurface tile drains is still poorly understood. We monitored the neonicotinoid insecticides imidacloprid and thiamethoxam from sugar beet seed dressings in flow-proportional drainage water samples, together with spray applications of bromide and the herbicide S-metolachlor in spring and the fungicides epoxiconazole and kresoxim-methyl in summer. Event-driven, high first concentration maxima up to 2830 and 1290 ng/L for thiamethoxam and imidacloprid, respectively, were followed by an extended period of tailing and suggested preferential flow. Nevertheless, mass recoveries declined in agreement with the degradation and sorption properties collated in the groundwater ubiquity score, following the order bromide (4.9%), thiamethoxam (1.2%), imidacloprid (0.48%), kresoxim-methyl acid (0.17%), S-metolachlor (0.032%), epoxiconazole (0.013%), and kresoxim-methyl (0.003%), and indicated increased leaching from seed dressings compared to spray applications. Measured concentrations and mass recoveries indicate that subsurface tile drains contribute to surface water contamination with neonicotinoids from seed dressings.


Assuntos
Monitoramento Ambiental , Água Subterrânea/química , Imidazóis/análise , Inseticidas/análise , Nitrocompostos/análise , Oxazinas/análise , Solo/química , Tiazóis/análise , Poluentes Químicos da Água/análise , Agricultura , Beta vulgaris , Brometos/análise , Cromatografia Líquida de Alta Pressão , Compostos de Epóxi/análise , Herbicidas/análise , Metacrilatos/análise , Neonicotinoides , Fenilacetatos/análise , Sementes , Poluentes do Solo , Espectrometria de Massas por Ionização por Electrospray , Estrobilurinas , Tiametoxam , Triazóis/análise
13.
J Pharm Biomed Anal ; 128: 264-274, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27281582

RESUMO

Sedative and anxiolytic-like properties of flavonoids such as kaempferol and quercetin, and of some of their intestinal metabolites, have been demonstrated in pharmacological studies. However, routes of administration were shown to be critical for observing in vivo activity. Therefore, the ability to cross intestinal and blood-brain barriers was assessed in cell-based models for kaempferol (KMF), and for the major intestinal metabolite of KMF, 4-hydroxyphenylacetic acid (4-HPAA). Intestinal transport studies were performed with Caco-2 cells, and blood-brain barrier transport studies with an immortalized monoculture human model and a primary triple-co-culture rat model. UHPLC-MS/MS methods for KMF and 4-HPAA in Ringer-HEPES buffer and in Hank's balanced salt solution were validated according to industry guidelines. For all methods, calibration curves were fitted by least-squares quadratic regression with 1/X(2) as weighing factor, and mean coefficients of determination (R(2)) were >0.99. Data obtained with all barrier models showed high intestinal and blood-brain barrier permeation of KMF, and no permeability of 4-HPAA, when compared to barrier integrity markers.


Assuntos
Barreira Hematoencefálica/química , Barreira Hematoencefálica/metabolismo , Absorção Intestinal , Quempferóis/análise , Quempferóis/farmacocinética , Fenilacetatos/análise , Animais , Células CACO-2 , Calibragem , Células Cultivadas , Técnicas de Cocultura , Simulação por Computador , Humanos , Ratos , Ratos Wistar , Padrões de Referência , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
14.
Environ Monit Assess ; 188(6): 341, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27168328

RESUMO

Benzene kresoxim-methyl (BKM) is a new strobilurin fungicide mixed with fluazinam (Flu) into 40 % suspension concentrate (SC) formulation to improve fungicidal efficacy and to reduce the risk of resistance on cucumber. However, the fate of the fungicide residues in a cucumber plantation remains unclear. Thus, an efficient method of ultra-performance liquid chromatography combined with a modified quick, easy, cheap, effective, rugged, and safe sample preparation was developed to simultaneously determine the BKM and Flu residues in cucumber and soil samples to investigate their residual behavior and risk assessment in the cucumber plantation. This analytical method revealed that the detection limits of BKM and Flu were 1.64 × 10(-3) and 1.82 × 10(-3) mg L(-1), respectively, and their average recoveries in the cucumber and soil samples were 77.5-106.9 %. The respective half-lives of BKM and Flu were 2.2-3.4 and 1.0-2.5 days in cucumber; in soil, the half-lives of BKM and Flu were 2.6-5.0 and 2.4-5.3 days, respectively. Seven days after application, the terminal residues of BKM and Flu in cucumber were less than 0.02 mg kg(-1). The residual profiles of BKM and Flu suggested that these fungicides could rapidly degrade in cucumber plantations. Their hazard quotient values were all less than 1 on the preharvest intervals of 3, 5, and 7 days, indicating that the dietary risk of BKM and Flu 40 % SC with the recommended usage on cucumber is negligible.


Assuntos
Aminopiridinas/análise , Cucumis sativus/química , Contaminação de Alimentos/análise , Fungicidas Industriais/análise , Fenilacetatos/análise , Poluentes do Solo/análise , Adulto , Cromatografia Líquida , Monitoramento Ambiental , Humanos , Metacrilatos/análise , Medição de Risco , Estrobilurinas
15.
J Agric Food Chem ; 63(48): 10366-71, 2015 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-26492351

RESUMO

Probabilistic exposure and risk assessment of kresoxim-methyl were conducted for agricultural applicators during preparation of spray suspension and application with a speed sprayer on an apple orchard. The preparation and application of 1000 L of spray suspension were repeated 30 times. Several exposure matrices, including patches, cotton gloves, socks, masks, and XAD-2 resin, were used to measure the potential exposure for workers. The analytical methods were fully validated to guarantee the precision and accuracy of analysis. The exposure amount on hands for mixer/loader was 0.7 mg [95% confidence interval (CI) from 0.02 to 2.4], taking 0.0005% (95% CI from 1.2 × 10(-5) to 0.001) of total prepared active ingredient. During application of kresoxim-methyl, the amount of dermal exposure was 17.5 mg (95% CI from 9.3 to 28.9), corresponding to 0.010% (95% CI from 0.006 to 0.017) of total applied active ingredient. The major exposure parts of the body were thighs and shins, with correlation coefficients of 0.53 and 0.43, respectively. The inhalation exposure during application were estimated as 6.8 ng (95% CI from 0.4 to 17.0), being 0.04% (95% CI from 0.004 to 0.06) of the dermal exposure. The calculated absorbable quantities of exposures for mixer/loader and applicator were 2.1 × 10(-4) mg/day (95% CI from 5.0 × 10(-6) to 7.2 × 10(-4)) and 2.3 mg/day (95% CI from 1.2 to 3.8), respectively. For risk assessment, the margin of safety of all working activities was much higher than 1, indicating that the possibility of risk to kresoxim-methyl was unlikely.


Assuntos
Fungicidas Industriais/análise , Malus/crescimento & desenvolvimento , Fenilacetatos/análise , Adulto , Agricultura/instrumentação , Humanos , Exposição por Inalação/análise , Masculino , Malus/efeitos dos fármacos , Metacrilatos/análise , Exposição Ocupacional/análise , Medição de Risco , Estrobilurinas
16.
J Environ Manage ; 161: 350-357, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26203874

RESUMO

Long term residues of organochlorine pesticides (OCPs) in soils are of great concerning because they seriously threaten food security and human health. This article focuses on isolation of OCP-degrading strains and their performance in bioremediation of contaminated soil under ex situ conditions. A bacterium, Chryseobacterium sp. PYR2, capable of degrading various OCPs and utilizing them as a sole carbon and energy source for growth, was isolated from OCP-contaminated soil. In culture experiments, PYR2 degraded 80-98% of hexachlorocyclohexane (HCH) or 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) isomers (50 mg L(-1)) in 30 days. A pilot-scale ex situ bioremediation study of highly OCP-contaminated soil augmented with PYR2 was performed. During the 45-day experimental period, DDT concentration was reduced by 80.3% in PYR2-augmented soils (35.37 mg kg(-1) to 6.97 mg kg(-1)) but by only 57.6% in control soils. Seven DDT degradation intermediates (metabolites) were detected and identified in PYR2-augmented soils: five by GC/MS: 1,1-dichloro-2,2-bis (4-chlorophenyl) ethane (DDD), 1,1-dichloro-2,2-bis (4-chlorophenyl) ethylene (DDE), 1-chloro-2,2-bis (4-chlorophenyl) ethylene (DDMU), 1-chloro-2,2-bis (4-chlorophenyl) ethane (DDMS), and dichlorobenzophenone (DBP); and two by LC/MS: 4-chlorobenzoic acid (PCBA) and 4-chlorophenylacetic acid (PCPA). Levels of metabolites were fairly stable in control soils but varied greatly with time in PYR2-augmented soils. Levels of DDD, DDMU, and DDE in PYR2-augmented soils increased from day 0 to day 30 and then decreased by day 45. A DDT biodegradation pathway is proposed based on our identification of DDT metabolites in PYR2-augmented systems. PYR2 will be useful in future studies of OCP biodegradation and in bioremediation of OCP-contaminated soils.


Assuntos
Chryseobacterium/metabolismo , DDT/metabolismo , Praguicidas/metabolismo , Poluentes do Solo/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental , Clorobenzoatos/análise , Clorobenzoatos/metabolismo , Humanos , Hidrocarbonetos Clorados/metabolismo , Isomerismo , Praguicidas/análise , Fenilacetatos/análise , Fenilacetatos/metabolismo , Poluentes do Solo/análise
17.
Environ Monit Assess ; 187(7): 436, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26082423

RESUMO

The sorption and leaching behavior of kresoxim-methyl was explored in four different soils, viz., clay, sandy loam, loamy sand, and sandy loam (saline), representing vegetables and fruits growing regions of India. Adsorption of kresoxim-methyl in all the soils reached equilibrium within 48 h. The rate constants for adsorption and desorption at two different temperatures were obtained from the Lindstrom model, which simultaneously evaluated adsorption and desorption kinetics. The data for rate constants, activation energies, enthalpy of activation, entropy of activation, and free energy indicated physical adsorption of kresoxim-methyl on soil. The relative adsorptivity of the test soils could be attributed to different organic matter and clay contents of the soils. A good fit to the linear and Freundlich isotherms was observed for both adsorption as well as desorption. The groundwater ubiquity score (GUS) for different soils varied between 0 and 2.26. The GUS and leaching study indicated moderately low leaching potential of kresoxim-methyl. The adsorption on four soil types largely depended on the soil physicochemical properties such as organic carbon content, cation-exchange capacity, and texture of the soil.


Assuntos
Fenilacetatos/química , Poluentes do Solo/química , Poluição Química da Água , Adsorção , Silicatos de Alumínio , Argila , Entropia , Índia , Cinética , Metacrilatos/análise , Metacrilatos/química , Fenilacetatos/análise , Medição de Risco , Solo/química , Estrobilurinas , Termodinâmica
18.
Analyst ; 140(9): 3039-47, 2015 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-25785694

RESUMO

Caged compounds have been used extensively to investigate neuronal function in a variety of preparations, including cell culture, ex vivo tissue samples, and in vivo. As a first step toward electrochemically measuring the extent of caged compound photoactivation while also measuring the release of the catecholamine neurotransmitter, dopamine, fast-scan cyclic voltammetry at carbon-fiber microelectrodes (FSCV) was used to electrochemically characterize 4-hydroxyphenylacetic acid (4HPAA) in the absence and presence of dopamine. 4HPAA is a by-product formed during the process of photoactivation of p-hydroxyphenacyl-based caged compounds, such as p-hydroxyphenylglutamate (pHP-Glu). Our data suggest that the oxidation of 4HPAA occurs through the formation of a conjugated species. Moreover, we found that a triangular waveform of -0.4 V to +1.3 V to -0.4 V at 600 V s(-1), repeated every 100 ms, provided an oxidation current of 4HPAA that was enhanced with a limit of detection of 100 nM, while also allowing the detection and quantitation of dopamine within the same scan. Along with quantifying 4HPAA in biological preparations, the results from this work will allow the electrochemical measurement of photoactivation reactions that generate 4HPAA as a by-product as well as provide a framework for measuring the photorelease of electroactive by-products from caged compounds that incorporate other chromophores.


Assuntos
Dopamina/análise , Técnicas Eletroquímicas/instrumentação , Fenilacetatos/análise , Carbono/química , Fibra de Carbono , Desenho de Equipamento , Microeletrodos , Oxirredução
19.
Environ Monit Assess ; 187(1): 4126, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25446716

RESUMO

The dissipation and terminal residues of a fungicide suspension (5% hexaconazole, 25% kresoxim-methyl) in ginseng and soil were investigated by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). At fortified levels of 0.01, 0.02, and 0.20 mg kg(-1), the recoveries of hexaconazole and kresoxim-methyl were in the range of 80.6∼94.8% and 82.4∼98.8% with relative standard deviation of 3.42-9.12% and 3.19-8.58%, respectively. The half-lives were 7.09-10.73 days in root, 6.80-7.95 days in stem, 5.31-8.49 days in leaf, and 6.30-7.97 days in soil. The terminal residues were all below the maximum residue limits (MRLs) of EU and South Korea. Risk assessment results indicated that the risk of hexaconazole and kresoxim-methyl use in ginseng at dosage of 60-90 g a.i. ha(-1) was negligible to humans. This work would help the government to establish the MRL and provide guidance on the proper and safe use of hexaconazole and kresoxim-methyl in ginseng.


Assuntos
Fungicidas Industriais/análise , Panax/química , Resíduos de Praguicidas/análise , Fenilacetatos/análise , Solo/química , Triazóis/análise , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental , Meia-Vida , Metacrilatos/análise , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , República da Coreia , Poluentes do Solo/análise , Estrobilurinas , Espectrometria de Massas em Tandem
20.
J Agric Food Chem ; 62(47): 11488-504, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25354220

RESUMO

A large variety of soluble phenolic compounds, including phenolic acids (hydroxybenzoic acids, ethyl protocatechuate, and hydroxycinnamic acids, as well as phenylacetic acid and phenyllactic acid), stilbenes (trans-piceatannol and trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene), flavan-3-ols (e.g., (-)-epicatechin, (+)-catechin, (-)-epiafzelechin, and their polymers (the proanthocyanidins, PACs)), other flavonoids (e.g., isoflavones, flavanols, and flavones), and biflavonoids, were released from esters and glycosides by base/acid hydrolysis and identified in acetonic extracts of dry-blanched peanut skins (PS). Reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS(n)) was applied to separate and identify the phenolic constituents. Tentative identification of the separated phenolics was based on molecular ions and MS(n) fragmentation patterns acquired by ESI-MS in the negative-ion mode. Identification of free phenolic acids, stilbenes, and flavonoids was also achieved by commercial standards and by published literature data. Quantification was performed on the basis of peak areas of the UV signals from the HPLC chromatograms and calibration curves of the commercial standards. The flavonoids of PS exist mostly in glycoside-bound forms, but the aglycones can be liberated upon acid hydrolysis. PS contain significantly more PACs compared to free phenolic compounds: PAC monomers to tetramers constituted 92.0% of esterified phenolic compounds. The PAC monomer ((+)-catechin) and dimers are the main phenolics released from glycosides and account for 31.7 and 59.1%, respectively, of the total glycoside-bound phenolic compounds.


Assuntos
Arachis/química , Cromatografia Líquida/métodos , Glicosídeos/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Cromatografia de Fase Reversa , Ácidos Cumáricos/análise , Flavonoides/análise , Hidroxibenzoatos/análise , Fenóis/análise , Fenilacetatos/análise , Extratos Vegetais/química , Estilbenos/análise
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