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1.
Int J Nanomedicine ; 14: 7707-7727, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31571873

RESUMO

Background: The encapsulation of plant essential oils (EOs) with polymeric materials (e.g. chitosan (CS) and N, N, N-trimethyl chitosan (TMC)) and the further reduction of the polymers into their nano sizes are gaining research interest in nanotechnology due to potential applications in medical drug delivery systems as well as the food and pharmaceutical industry. The present study reports a novel approach for the synthesis of Ocimum gratissimum essential oil (OGEO)-loaded CS and TMC nanoparticles with distinct bioactive and physiochemical properties. Methods: The OGEO-loaded CS and TMC nanoparticles were characterised using various microscopic and spectroscopic techniques. The bioactive compounds in Ocimum gratissimum methanolic extract (OG-MeOH) and EOs was evinced with gas chromatography-mass spectrometry (GC-MS). Total phenolic content (TPC) of OGEO and OG-MeOH was determined using the Folin-Ciocalteu method. The in vitro drug release kinetic pattern was ascertained by membrane dialysis, while antioxidant activity was determined by the 2,2-diphenyl-1picrylhydrozyl (DPPH) free radical scavenging method. The disc diffusion method was used for antibacterial activity evaluation, while MTT and a trypan blue dye exclusion assay were used to assess cytotoxic activity on MDA-MB-231 breast cancer cells. Results: GC-MS analysis revealed components that have not been previously reported for Ocimum gratissimum. The maximum OGEO cumulative drug release percentage in vitro was observed at pH 3 for both OGEO-loaded chitosan nanoparticles (OGEO-CSNPs) and OGEO-loaded N, N, N-trimethyl chitosan nanoparticles (OGEO-TMCNPs). The antioxidant activity of OGEO-CSNPs and OGEO-TMCNPs never reached a steady state after 75 h. OGEO-TMCNPs exhibited antibacterial activity at a lower concentration for both Gram-negative and Gram-positive food pathogens. In vitro cytotoxicity revealed the increased toxicity of OGEO-TMCNPs on MDA-MB-231 breast cancer cell lines. Conclusion: OGEO-loaded CS and TMC nanoparticles were synthesised using a novel material optimisation approach. The synthesised nanoparticles have shown a promising application in the pharmaceutical and food industries.


Assuntos
Quitosana/química , Liberação Controlada de Fármacos , Nanopartículas/química , Ocimum/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Compostos de Bifenilo/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Depuradores de Radicais Livres/química , Humanos , Cinética , Metanol/química , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Tamanho da Partícula , Fenóis/análise , Picratos/química , Extratos Vegetais/farmacologia , Óleos Vegetais/química , Eletricidade Estática
2.
J Chromatogr A ; 1604: 460494, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31488292

RESUMO

The objective of this study is to understand the behavior of a peptide in a medium containing supercritical carbon dioxide mixed with an alcohol (methanol) and acidic or basic additives in uncommonly high concentrations. Chirobiotic TAG is a chromatographic column made of silica bonded with a macrocyclic peptide, teicoplanin aglycone. With this stationary phase, two additives (trifluoroacetic acid and isopropylamine) were tested under extreme concentration conditions to observe the behavior of this peptide. Indeed, concentrations exceeding 1 M in the methanol co-solvent (>0.1 M overall concentration in the CO2-methanol mixture) were used whereas usual additive concentrations employed in supercritical fluid chromatography (SFC) rarely exceed 50 mM in the co-solvent. One purpose was to modify the apparent pH of the fluid, which is normally slightly acidic (around 5) and consequently possibly changing the ionization state of the peptide. Firstly, the effect of acidic and basic additives on the polarity and the apparent pH were evaluated with the help of color indicators. This served to assess the ionization state of the peptide under the selected operating conditions. Secondly, 54 achiral and 24 chiral molecules were injected in the chromatographic column at different levels of additives. The achiral species served at establishing retention models based on linear solvation energy relationships (LSER), while the chiral species were examined for their enantioresolution. From the LSER equations and observation of chromatograms, it appeared that specific interactions between the peptide-based stationary phase and the analytes evolved when increasing the concentration of additives, particularly hydrogen bonds and ionic interactions. A bare silica stationary phase (Acquity BEH) served as reference to deconvolute the contributions of silica support and bonded peptide. This study, with these extreme conditions of mobile phase, could be useful to understand the behavior of such peptides in SFC mobile phases and also improve the knowledge of the effects of additives in SFC, which should be helpful in the future prospect of analyzing large biomolecules in SFC.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Teicoplanina/análogos & derivados , Compostos Azabicíclicos/química , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Íons , Metanol/química , Piperazinas/química , Solventes/química , Estereoisomerismo , Teicoplanina/química , Teicoplanina/isolamento & purificação , Ácido Trifluoracético/química
3.
Pestic Biochem Physiol ; 159: 34-40, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400782

RESUMO

The present study investigated the insecticidal activity of the different organic extracts from the entomopathogenic fungi, Cladosporium cladosporioides, Metarhizium anisopliae, Purpureocillium lilacinum, and Trichoderma longibrachiatum towards cotton aphid, Aphis gossypii. The methanol extracts from the mycelia and spores of C. cladosporioides and P. lilacinum exhibited the highest insecticidal activity against A. gossypii compared with other extracts, which LC50 values were recorded to be 57.60 and 94.18 ppm, respectively. The major constituents identified in both methanol extracts by GC-MS analysis were linoleic acid and palmitic acid. The methanol extracts of C. cladosporioides and P. lilacinum caused a voluminous increase in the total carbohydrates content of A. gossypii adults, while the total protein content was significantly decreased by both extracts. The activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly reduced by methanol extracts. The P. lilacinum extract caused a considerable reduction in the activity of glutathione-S-transferase (GST), α- and ß-esterase by 28.9, 27.9 and 23.4%, respectively. Both extracts induced a significant increase in phenoloxidase and chitinase activity of A. gossypii adults. These results suggest that C. cladosporioides and P. lilacinum methanol extracts could be used as a promising approach for the management of A. gossypii in many economically crops.


Assuntos
Afídeos/efeitos dos fármacos , Gossypium/parasitologia , Inseticidas/farmacologia , Alanina Transaminase/genética , Alanina Transaminase/metabolismo , Animais , Quitinases/genética , Quitinases/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Resistência a Inseticidas/genética , Dose Letal Mediana , Metanol/química , Monofenol Mono-Oxigenase/genética , Monofenol Mono-Oxigenase/metabolismo
4.
J Agric Food Chem ; 67(35): 9840-9850, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31424924

RESUMO

In the present study, methanolysis of poplar biomass was conducted for the selective transformation of hemicellulose and lignin, which leads to methyl glycosides (mainly C5 glycosides) and lignin fragments in the liquefied products that can be separated according to their difference in hydrophilicity. The distribution of methyl glycosides and delignification was dependent on the presence of acid catalysts and reaction temperatures. The obtained lignin fraction was separated into solid lignin fragments and liquid lignin oil according to their molecular weight distribution. Subsequently, directional conversion of methyl C5 glycosides into methyl levulinate was performed with dimethoxymethane/methanol as the cosolvent. A yield of 12-30% of methyl levulinate yield (based on the methyl glycoside) was achieved under these conditions. The remaining cellulose-rich substrate showed enhanced susceptibility to enzymatic hydrolysis, resulting in a yield of glucose of above 70%. Overall, the described strategy shows practical implications for the effective valorization of biomass.


Assuntos
Fracionamento Químico/métodos , Glucose/isolamento & purificação , Ácidos Levulínicos/isolamento & purificação , Metanol/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Populus/química , Madeira/química , Catálise , Celulose/química , Celulose/isolamento & purificação , Glucose/química , Ácidos Levulínicos/química , Lignina/química , Lignina/isolamento & purificação , Fenóis/química , Extratos Vegetais/química
5.
J Chromatogr A ; 1603: 251-261, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31266644

RESUMO

Counter-current chromatography (CCC) is a unique, liquid-liquid partition chromatography process. Both the mobile and stationary phases are liquids, so no solid support matrix is used. CCC has gained wide acceptance as a preparative technique in a variety of fields. Because the mobile and stationary phases are both liquids, gradient elution is difficult to perform with CCC. Phase equilibrium must be maintained, so any change in the composition of one phase may induce a compositional change in the other. In this work, a new linear gradient elution method was developed for CCC. Biphasic solvent systems containing heptane, ethyl acetate, methanol, and water (HepEMWat) in various ratios were prepared and used to optimize both isocratic and linear gradient CCC separation with methanol. We first separated a test mixture of four standard compounds with partition coefficients ranging from 0.8 to 7.8. The separation resembled a reversed-phase process, and elution was performed while progressively decreasing the polarity of the mobile phase. Target molecules with small partition coefficients eluted first in the lower phase of the optimized HepEMWat solvent system. Elution of constituents with large partition coefficients was quite slow under isocratic conditions. Separation time was significantly reduced when elution was performed with a linear gradient using methanol and the optimal HepEMWat system. Elution with a 3:7:4:6 (v/v/v/v) HepEMWat system took approximately 200 min. This included an 80-min isocratic step, followed by gradient elution with methanol from 0% to 30%. The optimized methanol linear gradient CCC method was then used to separate a complex mixture of natural products isolated from Sinopodophyllum hexandrum (Royle) Ying roots. Twelve compounds with a wide range of polarities were well-resolved in a single separation. We have developed a convenient and cost-effective strategy for the separation of complex mixtures. No tedious mobile phase preparation step is required. The volume of unused mobile phase is minimal, so little solvent is wasted. The method is an important advance for the separation of mixtures that contain many compounds with a large range of polarities and partition coefficients, which are common features of natural products.


Assuntos
Berberidaceae/química , Produtos Biológicos/isolamento & purificação , Distribuição Contracorrente/métodos , Metanol/química , Cromatografia Líquida de Alta Pressão/métodos , Extratos Vegetais/isolamento & purificação , Solventes/química , Água/química
6.
Molecules ; 24(13)2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31288458

RESUMO

BACKGROUND/AIM: Plants play an important role in anti-cancer drug discovery, therefore, the current study aimed to evaluate the biological activity of Alpinia zerumbet (A. zerumbet) flowers. METHODS: The phytochemical and biological criteria of A. zerumbet were in vitro investigated as well as in mouse xenograft model. RESULTS: A. zerumbet extracts, specially CH2Cl2 and MeOH extracts, exhibited the highest potent anti-tumor activity against Ehrlich ascites carcinoma (EAC) cells. The most active CH2Cl2 extract was subjected to bioassay-guided fractionation leading to isolatation of the naturally occurring 5,6-dehydrokawain (DK) which was characterized by IR, MS, 1H-NMR and 13C-NMR. A. zerumbet extracts, specially MeOH and CH2Cl2 extracts, exhibited significant inhibitory activity towards tumor volume (TV). Furthermore, A. zerumbet extracts declined the high level of malonaldehyde (MDA) as well as elevated the levels of superoxide dismutase (SOD) and catalase (CAT) in liver tissue homogenate. Moreover, DK showed anti-proliferative action on different human cancer cell lines. The recorded IC50 values against breast carcinoma (MCF-7), liver carcinoma (Hep-G2) and larynx carcinoma cells (HEP-2) were 3.08, 6.8, and 8.7 µg/mL, respectively. CONCLUSION: Taken together, these findings open the door for further investigations in order to explore the potential medicinal properties of A. zerumbet.


Assuntos
Alpinia/química , Antineoplásicos Fitogênicos/química , Extratos Vegetais/química , Pironas/química , Animais , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Catalase/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clorofórmio/química , Flores/química , Xenoenxertos , Humanos , Malondialdeído/metabolismo , Metanol/química , Camundongos , Transplante de Neoplasias , Extratos Vegetais/farmacologia , Plantas Medicinais , Pironas/farmacologia , Solventes , Superóxido Dismutase/metabolismo
7.
Molecules ; 24(13)2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31288489

RESUMO

Black mulberry is a widely acknowledged ancient traditional medicine. Its extract and constituents have been reported to exert various bioactivities including antimicrobial, hypotensive, analgesic etc. effects. While black mulberry preparations are also used as antispasmodic agents in folk medicine, no related studies are available on its isolated constituents. Through an extensive chromatographic purification, seven phenolic compounds were isolated from the methanol extract of Morus nigra root bark, including morusin (1), kuwanon U (2), kuwanon E (3), moracin P (4), moracin O (5), albanol A (6), and albanol B (7). A complete NMR signal assignment of moracin P and O was achieved, and related literature errors confusing the identity of moracin derivatives are hereby clarified. Compounds 2, 5 and 7 were identified as strong antispasmodic agents on isolated rat ileum and tracheal smooth muscles, while compound 3, a methoxy derivative of 2, was inactive. Moracin O (5) inhibited the ileal and tracheal smooth muscle contractions with Emax values of 85% and 302 mg, respectively. Those actions were superior as compared with papaverine. Our findings demonstrate that prenylated arylbenzofurans, geranylated flavonoids and Diels-Alder adducts from Morus nigra are valuable antispasmodic agents. Compounds 2, 5 and 7 are suggested as marker compounds for quality control of antispasmodic mulberry preparations. Moracin O (5) is a new lead compound for related drug development initiatives.


Assuntos
Morus/química , Parassimpatolíticos/química , Fenóis/química , Casca de Planta/química , Extratos Vegetais/química , Raízes de Plantas/química , Benzofuranos/metabolismo , Avaliação Pré-Clínica de Medicamentos , Flavanonas/metabolismo , Metanol/química , Parassimpatolíticos/farmacologia , Prenilação , Resorcinóis/metabolismo , Solventes/química , Relação Estrutura-Atividade
8.
Chem Commun (Camb) ; 55(59): 8556-8559, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31271173

RESUMO

Non-hydrated organic solutions of a diphenylalanine amphiphile blocked at the C-terminus with a fluorenylmethyl ester and stabilized at the N-terminus with a trifluoroacetate have been used to prepare amyloid fibrils. The solvent used to prepare the stock solution together with the co-solvent added enables regulation of the characteristics of the fibrils, which is important for their use in technological applications.


Assuntos
Amiloide/síntese química , Proteínas Amiloidogênicas/química , Dipeptídeos/química , Tensoativos/química , Teoria da Densidade Funcional , Dimetilformamida/química , Metanol/química , Propanóis/química , Conformação Proteica em Folha beta , Multimerização Proteica , Teoria Quântica
9.
Phys Chem Chem Phys ; 21(28): 15478-15486, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31259327

RESUMO

Complex chemical and biochemical systems are susceptible to damage from ionising radiation. However, questions remain over the extent to which such damage is influenced by the nature of the surrounding chemical environment, which can consist of both hydrophobic and hydrophilic domains. To gain fundamental insight into the first crucial mechanistic steps of radiation damage in such systems, we need to understand the initial radiation response, i.e. dynamics occurring on the same timescale as electronic relaxation, which occur in these different environments. Amphiphilic molecules contain both hydrophobic and hydrophilic domains, but the propensity for charge delocalisation and proton dynamics to occur in these different domains has been largely unexplored so far. Here, we present carbon and oxygen 1s Auger spectra for liquid methanol, one of the simplest amphiphilic molecules, as well as its fully deuterated equivalent d4-methanol, in order to explore X-ray induced charge delocalisation and proton dynamics occurring on the few femtosecond timescale. Unexpectedly, we find a similar propensity for proton dynamics to occur at both the carbon and oxygen site within the lifetime of the core hole. Our results could serve as a model for decay processes that are likely to occur in other more complex amphiphilic systems.


Assuntos
Metanol/química , Metanol/efeitos da radiação , Raios X , Carbono/química , Oxigênio/química , Prótons
10.
Food Chem ; 298: 125067, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260989

RESUMO

An ultra-high performance supercritical fluid chromatography-photodiode array detection-mass spectrometry (UHPSFC-MS) method for quality control of Piper longum L. has been developed and optimized. Hexane/isopropanol (70/30, v/v) was determined as the final injection solvent and methanol as the organic modifier. A design-of-experimental (DoE) approach was used to optimize column temperature, back-pressure and the gradient slope simultaneously using Trefoil CEL1 column. The back-pressure, temperature, flow rate were set at 130 bar, 32.5 °C and 1.0 mL/min, respectively. Positive electrospray ionization was used in the single ion monitoring mode. The 12 analytes were analyzed within 8 min using the optimized conditions. The linearities of the standard calibrations were satisfactory with coefficients of determination (R2) > 0.995. The recovery measured varied from 96.34% to 105.00% with relative standard deviation (RSD) ≤ 4.68%. The method was sensitive, reliable and effective, and successfully applied to simultaneous determination of 12 compounds in 28 batches of P. longum.


Assuntos
Alcaloides/química , Cromatografia com Fluido Supercrítico/métodos , Piper/química , Alcaloides/isolamento & purificação , Benzodioxóis/química , Benzodioxóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Cromatografia com Fluido Supercrítico/normas , Frutas/química , Frutas/metabolismo , Limite de Detecção , Espectrometria de Massas , Metanol/química , Piper/metabolismo , Piperidinas/química , Piperidinas/isolamento & purificação , Alcamidas Poli-Insaturadas/química , Alcamidas Poli-Insaturadas/isolamento & purificação , Análise de Componente Principal , Controle de Qualidade , Solventes/química , Temperatura Ambiente
11.
Talanta ; 202: 436-442, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171205

RESUMO

A disposable blood sampler, which is consisted of a sub-microliter whole blood collector and a graphene filter, loading graphene sheet to selectively capture hemoglobin from sub-microliter whole blood, was developed for both qualitative and quantitative characterization hemoglobin by internal extractive electrospray ionization mass spectrometry (iEESI-MS). The blood collector was elegantly fabricated in syringe-like fashion for precisely sampling tiny amounts (1.0 µL - 2%) of whole blood, which was immediately diluted by water inside the syringe and was then pressed through the graphene filter placed between the waste outlet and the syringe reservoir to capture the hemoglobin in the blood sample. Then the graphene with hemoglobin was directly eluted by a charged (+2.5 kV) solution (mathanol/water/formic acid, 48/48/4, v/v/v) to produce the hemoglobin ions for mass spectrometric analysis. Low detection-of-limit (19.3 mg L-1 (89.5 picomol)), acceptable linear response range (300-1500 mg L-1, R2 = 0.998), relative standard deviation (0.5-6.5%, n = 3), low sample consumption (≤1.0 µL) and a relatively high speed (≤4 min per sample, including the sample loading) were achieved, demonstrating that the graphene based iEESI-MS was an alternative choice for direct detection of hemoglobin in whole blood with minimal sample consumption.


Assuntos
Grafite/química , Hemoglobinas/isolamento & purificação , Formiatos , Hemoglobinas/química , Humanos , Limite de Detecção , Metanol/química , Espectrometria de Massas por Ionização por Electrospray , Água/química
12.
Ultrason Sonochem ; 57: 89-97, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31208622

RESUMO

This paper presents the successful application of ultrasound-assisted packed-bed (UAE-PB) method for the extraction of hypericin from the Hypericum perfuratum L. The Soxhlet system was utilized for the determination of suitable solvent from ethanol, methanol or from the mixture of different proportions of ethanol-methanol. The mixture of 50:50 v/v ethanol-methanol was obtained to be the most suitable solvent since it led to the highest extraction amount of hypericin. The extraction amount of hypericin increased by 13.6% and 21.4% when the solvent changed from pure methanol to the mixture of 50:50 v/v ethanol-methanol for the extraction time of 3 and 8 h, respectively. Subsequently, the extraction was conducted through the UAE-PB, and the effects of temperature, time, and the ratio of solvent to the dried plant were studied. The response surface method (RSM) was used to investigate the effect of parameters on the extraction in the UAE-PB system. At the temperature of 60 °C, extraction time of 105 min, and the solvent to plant ratio of 15.3, the maximum extraction yield of hypericin was achieved. In the optimal conditions, the amount of extraction was 0.112 mg hypericin/g dried plant, which was in accordance with the optimized predicted value (0.111 mg hypericin/g dried plant) from Design-Expert software.


Assuntos
Hypericum/química , Perileno/análogos & derivados , Ondas Ultrassônicas , Cromatografia Líquida de Alta Pressão/métodos , Etanol/química , Metanol/química , Modelos Químicos , Perileno/análise , Reprodutibilidade dos Testes , Solventes/química , Temperatura Ambiente , Fatores de Tempo
13.
J Chromatogr A ; 1603: 348-354, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31164229

RESUMO

Uncommon retention behavior of a series of n-alkylbenzene homologues as well as the effect of different sample solvents on chromatographic efficiency were studied in supercritical fluid chromatography. After testing various columns, an alkylamide stationary phase was selected for detailed studies. The results showed that even a small amount of methanol originating only from the sample, overloaded the column and competitive adsorption was induced between the analytes and the sample solvent for adsorption on the stationary phase. This was indicated by the changes in column efficiency, retention and peak widths. The concentration of the analytes in the sample was negligible compared to the amount of methanol - but their adsorption was influenced by the solvent - while the adsorption of methanol remained unaffected by the n-alkylbenzenes. First, the competition was described by determining the single-component adsorption isotherms for both the analytes and their solvent, then competitive isotherms were calculated. Based on the peak profiles, bi-Langmuir and competitive bi-Langmuir isotherms were assumed. The solvent effect was modeled by a numerical method created in-house where the differential mass balance equation given by the equilibrium-dispersive (ED) model was integrated using the Rouchon algorithm. The experimental observations were confirmed by in silico experiments and additional cases involving two hypothetical analytes were studied as well.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Solventes/química , Adsorção , Simulação por Computador , Heptanos/química , Metanol/química , Temperatura Ambiente
14.
Food Chem Toxicol ; 131: 110535, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31154083

RESUMO

This study endeavours to investigate the phytochemical composition, biological properties and in vivo toxicity of methanol and dichloromethane extracts of Zaleya pentandra (L.) Jeffrey. Total bioactive contents, antioxidant (phosphomolybdenum and metal chelating, DPPH, ABTS, FRAP and CUPRAC) and enzyme inhibition (cholinesterases, tyrosinase α-amylase, and α-glucosidase) potential were assessed utilizing in vitro bioassays. UHPLC-MS phytochemical profiling was carried out to identify the essential compounds. The methanol extract was found to contain highest phenolic (22.60 mg GAE/g) and flavonoid (31.49 mg QE/g) contents which correlate with its most significant radical scavenging, reducing potential and tyrosinase inhibition. The dichloromethane extract was most potent for phosphomolybdenum, ferrous chelation, α-amylase, α-glucosidase, and cholinesterase inhibition assays. UHPLC-MS analysis of methanol extract unveiled to identify 11 secondary metabolites belonging to five sub-groups, i.e., phenolic, alkaloid, carbohydrate, terpenoid, and fatty acid derivatives. Additionally, in vivo toxicity was conducted for 21 days and the methanol extract at different doses (150, 200, 250 and 300 mg/kg) was administered in experimental chicks divided into five groups each containing five individuals. Different physical, haematological and biochemical parameters along with the absolute and relative weight of visceral body organs were studied. Overall, no toxic effect was noted for the extract at tested doses.


Assuntos
Aizoaceae/química , Extratos Vegetais/farmacologia , Extratos Vegetais/toxicidade , Administração Oral , Animais , Galinhas , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/toxicidade , Depuradores de Radicais Livres/administração & dosagem , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/farmacologia , Depuradores de Radicais Livres/toxicidade , Metanol/química , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química
15.
Food Chem ; 297: 124998, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253278

RESUMO

The analysis of free fatty acids (FFAs) in edible oils can provide important information for quality control and oil authentication. Herein, we report the comprehensive profiling of FFAs in edible oils via magnetic dispersive extraction combined with comprehensive two-dimensional gas chromatography-mass spectrometry (GC × GC-MS). A magnetic extractant was designed for dispersive extraction of FFAs. The extraction conditions were carefully optimized. To assess the extraction method, we first use the method for analysis of 7 targeted FFAs. The limits of detection range from 5.6 to 25.8 ng g-1, and the recoveries in oil samples are 81%-107%. We then performed comprehensive profiling of untargeted FFAs in oil by combining the extraction method with GC × GC-MS. A total of 64 FFAs were identified positively or putatively. The proposed method can provide FFA fingerprint data to guide the processing, storage and authentication of edible oils.


Assuntos
Ácidos Graxos não Esterificados/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Magnetismo , Óleos Vegetais/química , Amônia/química , Ácidos Graxos não Esterificados/isolamento & purificação , Óxido Ferroso-Férrico/química , Metanol/química , Dióxido de Silício/química
16.
Chemosphere ; 233: 327-335, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176895

RESUMO

An amino-functionalized magnetic metal organic framework (MOF), Fe3O4-NH2@MIL-101(Cr), was employed for laccase immobilization for the first time. The immobilized laccase was synthesized by the adsorption and covalent binding method, thus exhibited high activity recovery, large immobilization capacity and good tolerance to low pH and high temperature conditions. The excellent stability enabled the immobilized laccase to retain 89% of its initial activity after storage for 28 days. When the ambient temperature reached 85 °C, the immobilized laccase showed 49.1% residual activity even after 6 h preservation. The stability of laccase in organic solvents such as methanol was also greatly improved. Application of the immobilized laccase for 2,4-dichlorophenol removal was also investigated. The adsorption by Fe3O4-NH2@MIL-101(Cr) contributed to a quick removal in the first hour, and the removal efficiency reached 87% eventually. When the reaction was completed, the immobilized laccase could be separated from the solution by a magnet. The results introduced a novel support for laccase immobilization, and the immobilized laccase had great potential in wastewater treatment.


Assuntos
Lacase/química , Estruturas Metalorgânicas/química , Fenóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Clorofenóis/química , Clorofenóis/isolamento & purificação , Estabilidade Enzimática , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Magnetismo , Imãs , Metanol/química , Fenóis/química , Temperatura Ambiente , Águas Residuárias , Poluentes Químicos da Água/química
17.
J Chromatogr A ; 1600: 183-196, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31053351

RESUMO

A semi-quantitative method was developed to monitor the misuse of 15 SARM compounds belonging to nine different families, in urine matrices from a range of species (equine, canine, human, bovine and murine). SARM residues were extracted from urine (200 µL) with tert-butyl methyl ether (TBME) without further clean-up and analysed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). A 12 min gradient separation was carried out on a Luna Omega Polar C18 column, employing water and methanol, both containing 0.1% acetic acid (v/v), as mobile phases. The mass spectrometer was operated both in positive and negative electrospray ionisation modes (ESI±), with acquisition in selected reaction monitoring (SRM) mode. Validation was performed according to the EU Commission Decision 2002/657/EC criteria and European Union Reference Laboratories for Residues (EU-RLs) guidelines with CCß values determined at 1 ng mL-1, excluding andarine (2 ng mL-1) and BMS-564929 (5 ng mL-1), in all species. This rapid, simple and cost effective assay was employed for screening of bovine, equine, canine and human urine to determine the potential level of SARMs abuse in stock farming, competition animals as well as amateur and elite athletes, ensuring consumer safety and fair play in animal and human performance sports.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão/normas , Espectrometria de Massas em Tandem/normas , Urinálise/métodos , Antagonistas de Receptores de Andrógenos , Animais , Bovinos , Cães , Cavalos , Humanos , Metanol/química , Camundongos , Receptores Androgênicos/metabolismo , Reprodutibilidade dos Testes , Urinálise/normas
18.
J Chromatogr A ; 1600: 219-237, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31060782

RESUMO

A simple chromatographic model including extra-column sample bandspreading is built and validated experimentally. It is used to quantify the advantage of slowly transporting under isocratic elution of the injected sample band along the pre-column volume of the chromatographic system compared to the conventional injection method at constant flow rate. For fast analyses (<30 s), the model predicts a maximum relative gain of 20% for the isocratic peak capacity of weakly retained compounds (k < 1) at the price of a 60% increase in retention time (+20 s) for short (3.0 cm long) narrow-bore (2.1 mm i.d.) columns packed with sub-2 µm particles and for low-dispersion (∼2 µL2 extra-column volume variance) vHPLC systems. These predictions were confirmed experimentally using a 2.1 mm × 30 mm column packed with 1.9 µm XBridge-C18 for the rapid separation of small molecules in 25 s at 40 °C using a mixture of methanol and water (75/25, v/v) as the eluent. For longer analyses (>30 s), the model allows for the determination of the optimum and slow injection speed that maximizes the trade-off between the analysis time and the isocratic peak capacity. For 2.1 mm × 20 mm columns packed with 2 µm particles and a highest retention factor of 10, the optimum injection speed is about 10-15% of the operating column flow rate for a maximum relative gain of 5% in overall isocratic peak capacity at constant elution time. Overall, the proposed injection method is directly applicable for enhanced resolution of weakly retained polar compounds in RPLC without the need of changing separation conditions, which may strongly increase the retention times of the late apolar eluters.


Assuntos
Cromatografia Líquida/métodos , Modelos Teóricos , Cromatografia Líquida/instrumentação , Metanol/química , Água/química
19.
J Chromatogr A ; 1600: 112-126, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31128882

RESUMO

The solvation parameter model is used to characterize the retention properties of 25 siloxane-bonded type-B silica columns under typical reversed-phase liquid chromatography conditions with binary aqueous mobile phases containing 10-70% (v/v) methanol and acetonitrile. To further explore the affect of solvent type on column selectivity complementary information is presented for aqueous phases containing 10-70% (v/v) tetrahydrofuran for two columns. Columns were selected to include examples of all common column packing morphologies for small molecule separations (totally porous particles, superficially porous particles, organic-inorganic hybrid particles, and a monolith) and common topologies octadecylsiloxane-bonded (including phases with a polar-embedded group, mixed-mode phases with a short-chain siloxane-bonded polar functional group, sterically crowded, positive shield, and fluorine-containing phases); octylsiloxane-bonded; and various phenyl-containing stationary phases with different linker arms, pentafluorophenylalkyl and biphenyl groups. The column properties are reported as a system constant database and as system maps for the full range of mobile phase compositions. Selectivity differences are evaluated using principal component factor analysis to classify the columns into selectivity groups and correlation plots of the system constants for compared columns at all mobile phase compositions. The later is shown to be a suitable technique to identify (near) selectivity equivalent columns and varied columns suitable for method development. Contributions to retention from steric resistance and cation-exchange interactions not parameterized in the solvation parameter model are identified for columns and conditions where they may be important. It is shown that the interaction parameters employed in the hydrophobic-subtraction model have little overlap with those of the solvation parameter model and a quantitative comparison of column properties delineated by both models is not possible.


Assuntos
Cromatografia de Fase Reversa , Bases de Dados Factuais , Dióxido de Silício/química , Siloxanas/química , Solventes/química , Acetonitrilos/química , Interações Hidrofóbicas e Hidrofílicas , Indicadores e Reagentes , Metanol/química , Porosidade , Água/química
20.
Food Chem ; 294: 123-129, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126444

RESUMO

We previously reported a humidity-mediated method to effectively remove methanol from the crystal lattice of 3',5'-cyclic monophosphate sodium (cAMPNa) methanol trihydrate, converting it to the pentahydrate without changing its inherent orthorhombic packing mode, and preserving its stability. In this paper, we expand this approach to the removal of residual solvents from l-lysine l-glutamate salt and inosine-5'-monophosphate, and contrast the humidity-mediated method with a solvent-mediated method and a conventional drying method. The packing density of the products obtained from the humidity-mediated method were ∼60% higher than those of the products obtained from the solvent-mediated method, and their stability is ∼5-10% higher than those obtained from the solvent-mediated and traditional drying methods. Furthermore, the humidity-mediated method can remove residual methanol more completely. Therefore, the humidity-mediated method can be regarded as a simple and effective route to eliminate residual solvent from crystal lattice for some crystal products, especially residual methanol.


Assuntos
Ácido Glutâmico/química , Lisina/química , Solventes/química , Cristalização , Umidade , Inosina Monofosfato/química , Metanol/química , Difração de Raios X
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