Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Carbohydr Res ; 481: 52-59, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31247450

RESUMO

High efficiency conversion of cellulose to 5-hydroxymethylfurfural (HMF) remains a challenge today. A simple solid acid catalyst Boehmite (γ-AlOOH) with high hydrothermal stability was prepared and used as sole catalyst for the direct conversion of cellulose into HMF in mixed reaction solvents of ionic liquid 1-buthyl-3-methylimidazolium chloride (BmimCl) and dimethyl sulfoxide (DMSO). This was aimed at developing an efficient and inexpensive catalyst for the production of HMF. The effects of factors such as water, solvent, catalyst load, temperature and reaction duration were investigated. An impressive HMF yield of 58.4% with 97.2% cellulose conversion was obtained at 160 °C after 2 h. More importantly, the catalyst γ-AlOOH was reused several times without loss of its catalytic properties. After five reaction runs, an HMF yield of 47.8% with 91.0% conversion was also obtained. In addition, the catalyst γ-AlOOH displayed excellent catalytic effects on the degradation of other carbohydrates. High yields of HMF from other carbohydrates such as glucose (61.2%), starch (62.7%) and inulin (70.5%) were achieved using γ-AlOOH as the catalyst. The proposed catalytic method shows a promising potential for HMF preparation, especially for industrial-scale HMF production from renewable bioresources.


Assuntos
Hidróxido de Alumínio/química , Óxido de Alumínio/química , Celulose/química , Custos e Análise de Custo , Furaldeído/análogos & derivados , Catálise , Furaldeído/química , Glucose/química , Solventes/química , Temperatura Ambiente , Água/química
2.
J Oleo Sci ; 68(3): 261-271, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30760673

RESUMO

A simple solid base catalyst, ammonium aluminum carbonate hydroxide (AACH), was prepared and its structure was characterized by many technologies, including XRD, FT-IR, SEM, BET and Elemental Analysis. The prepared catalyst was used to catalyze the conversion of glucose into 5-hydroxymethylfurfural (HMF) in ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]+Cl-) and dimethyl sulfoxide (DMSO) mixtures. Various reaction conditions, including catalyst loading, reaction temperature, reaction duration and solvent, were investigated. A moderated HMF yield of 52.17 % was obtained at the mild reaction conditions (120°C for 4 h). More importantly, the catalyst could be reused for several times without the loss of its significant catalytic activities. After five reaction runs, a HMF yield about 49.34 % was also obtained.


Assuntos
Dimetil Sulfóxido/química , Furaldeído/análogos & derivados , Glucose/química , Imidazóis/química , Líquidos Iônicos/química , Carbonatos/química , Catálise , Frutose/química , Furaldeído/síntese química , Hidróxidos/química , Modelos Químicos , Solventes/química , Temperatura Ambiente
3.
Chem Commun (Camb) ; 54(85): 12105-12108, 2018 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-30302448

RESUMO

The double chloride-bridged dimer of a dinuclear dysprosium(iii) single-molecule magnet (SMM) was successfully isolated by assembling centrosymmetric dinuclear Dy2 SMMs. Such structural transformation involves the generation and cleavage of chloride bridges and leads to consecutive transformations of one- and two-step slow relaxation of magnetization.

4.
J Food Sci ; 81(4): H1001-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26930155

RESUMO

Peony seed oil (PSO) is a new resource food rich in α-Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein-cholesterol (LDL-C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n-6 to n-3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element-binding proteins 1C (SREBP-1c), acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS)-reduced lipid synthesis; Activation of peroxisome proliferator-activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl-CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.


Assuntos
Ácidos Graxos/metabolismo , Hipolipemiantes/farmacologia , Lipogênese/efeitos dos fármacos , Obesidade/metabolismo , Paeonia/química , Óleos Vegetais/farmacologia , Ácido alfa-Linoleico/farmacologia , Acil-CoA Oxidase/metabolismo , Animais , Metabolismo Energético/efeitos dos fármacos , Hipolipemiantes/uso terapêutico , Canais Iônicos/metabolismo , Lipídeos/sangue , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Proteínas Mitocondriais/metabolismo , Obesidade/prevenção & controle , Oxirredução , PPAR alfa/metabolismo , Óleos Vegetais/química , Óleos Vegetais/uso terapêutico , Ratos Wistar , Sementes/química , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína Desacopladora 2 , Regulação para Cima , Ácido alfa-Linoleico/metabolismo , Ácido alfa-Linoleico/uso terapêutico
5.
Int J Food Sci Nutr ; 67(1): 20-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26653879

RESUMO

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of ß-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.


Assuntos
Anticolesterolemiantes/farmacologia , Colesterol/metabolismo , Micelas , Momordica charantia , Extratos Vegetais/farmacologia , Esterol Esterase/metabolismo , Absorção Intestinal/efeitos dos fármacos , Pâncreas , Conformação Proteica , Solubilidade
6.
Food Funct ; 6(10): 3400, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26387553

RESUMO

Correction for 'Anti-diabetic activity of peony seed oil, a new resource food in STZ-induced diabetic mice' by Jianhui Su et al., Food Funct., 2015, 6, 2930-2938.

7.
Food Funct ; 6(9): 2930-8, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26245697

RESUMO

This study was conducted to investigate the components of a new resource food in China, peony seed oil (PSO) by GC-MS (gas chromatography-mass spectrometry), its inhibitory effects on carbohydrate hydrolyzing enzymes in vitro and its anti-diabetic effects on mice induced by streptozotocin (STZ). The results showed that peony seed oil showed weak anti-α-amylase activity; however, strong anti-α-glucosidase activity was noted. The GC-MS analysis of the oil showed 9 constituents of which α-linolenic acid was found to be the major component (38.66%), followed by linoleic acid (26.34%) and oleic acid (23.65%). The anti-diabetic potential of peony seed oil was tested in STZ induced diabetic mice. Administration of peony seed oil and glibenclamide reduced the blood glucose level and the area under curve (AUC) in STZ induced diabetic mice. There were significant increases in body weight, liver glycogen content, serum insulin level, high-density lipoprotein cholesterol (HDL-C) and decreases in glycosylated hemoglobin (HbA1C), total serum cholesterol (TC), and triglyceride (TG) in test groups as compared to the untreated diabetic groups. In vivo antioxidant studies on STZ induced diabetic mice revealed the reduction of malondialdehyde (MDA) and increase of glutathione peroxides (GSH-px), superoxide dismutase (SOD), and glutathione (GSH). The results provided a sound rationale for future clinical trials of oral administration of peony seed oil to alleviate postprandial hyperglycemia in streptozotocin-induced diabetic mice.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Paeonia/química , Óleos Vegetais/administração & dosagem , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/enzimologia , Feminino , Hemoglobina A Glicada/metabolismo , Humanos , Hipoglicemiantes/química , Insulina/sangue , Lipoproteínas HDL/sangue , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Óleos Vegetais/química , Sementes/química , Estreptozocina/efeitos adversos , Superóxido Dismutase/sangue , alfa-Amilases/metabolismo , alfa-Glucosidases/metabolismo
8.
PLoS One ; 9(2): e88886, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24551186

RESUMO

Conventional Sanger sequencing remains time-consuming and laborious. In this study, we developed a rapid improved sequencing protocol of 16S rRNA for pathogens identification by using a new combination of SYBR Green I real-time PCR and Sanger sequencing with FTA® cards. To compare the sequencing quality of this method with conventional Sanger sequencing, 12 strains, including three kinds of strains (1 reference strain and 3 clinical strains, which were previously identified by biochemical tests), which have 4 Pseudomonas aeruginosa, 4 Staphyloccocus aureus and 4 Escherichia coli, were targeted. Additionally, to validate the sequencing results and bacteria identification, expanded specimens with 90 clinical strains, also comprised of the three kinds of strains which included 30 samples respectively, were performed as just described. The results showed that although statistical differences (P<0.05) were found in sequencing quality between the two methods, their identification results were all correct and consistent. The workload, the time consumption and the cost per batch were respectively light versus heavy, 8 h versus 11 h and $420 versus $400. In the 90 clinical strains, all of the Pseudomonas aeruginosa and Staphyloccocus aureus strains were correctly identified, but only 26.7% of the Escherichia coli strains were recognized as Escherichia coli, while 33.3% as Shigella sonnei and 40% as Shigella dysenteriae. The protocol described here is a rapid, reliable, stable and convenient method for 16S rRNA sequencing, and can be used for Pseudomonas aeruginosa and Staphyloccocus aureus identification, yet it is not completely suitable for discriminating Escherichia coli and Shigella strains.


Assuntos
Bactérias/genética , RNA Ribossômico 16S/genética , Análise de Sequência de RNA/métodos , Sequência de Bases , Eletroforese em Gel de Ágar , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Etídio/metabolismo , Genes Bacterianos , Humanos , Dados de Sequência Molecular , Desnaturação de Ácido Nucleico/genética , Reação em Cadeia da Polimerase , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/isolamento & purificação , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA