RESUMEN
Molecularly imprinted polymers (MIPs) for caffeic acid (CA) were prepared using 4-vinylpyridine and methacrylamide (MAM) as functional monomers, divinylbenzene as a crosslinker and acetonitrile-toluene (3:1, v/v) as a porogen by precipitation polymerization. The use of MAM as the co-monomer resulted in the formation of microsphere MIPs and non-imprinted polymers (NIPs) with ca. 3- and 5-µm particle diameters, respectively. Binding experiments and Scatchard analyses revealed that the binding capacity and affinity of the MIP to CA are higher than those of the NIP. The retention and molecular-recognition properties of the prepared MIPs were evaluated using water-acetonitrile and sodium phosphate buffer-acetonitrile as mobile phases in hydrophilic interaction chromatography (HILIC) and reversed-phase chromatography, respectively. In HILIC mode, the MIP showed higher molecular-recognition ability for CA than in reversed-phase mode. In addition to shape recognition, hydrophilic interactions seem to work for the recognition of CA on the MIP in HILIC mode, while hydrogen bonding and hydrophobic interactions seem to work for the recognition of CA in reversed-phase mode. The MIP had a specific molecular-recognition ability for CA in HILIC mode, while other structurally related compounds, such as chlorogenic acid ï¼CGA), gallic acid, protocatechuic acid and vanillic acid, could not be recognized by the MIP. Furthermore, the MIP was successfully applied for extraction of CA and CGA in the leaves of Eucommia ulmodies in HILIC mode.
Asunto(s)
Ácidos Cafeicos/aislamiento & purificación , Precipitación Química , Ácido Clorogénico/aislamiento & purificación , Eucommiaceae/química , Impresión Molecular/métodos , Hojas de la Planta/química , Polímeros/química , Cromatografía de Fase Inversa , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía Electrónica de Rastreo , Estructura MolecularRESUMEN
Molecularly imprinted polymers (MIPs) for chlorogenic acid (CGA) were prepared by modified precipitation polymerization using methacrylic acid as a functional monomer, divinylbenzene as a crosslinker and methanol or dimethylsulfoxide as a co-solvent. The prepared MIPs were microspheres with a narrow particle size distribution. Binding experiments and Scatchard analyses revealed that two classes of binding sites, high and low affinity sites, were formed on the MIP. The retention and molecular-recognition properties of the prepared MIP were evaluated using a mixture of water and acetonitrile as a mobile phase in hydrophilic interaction chromatography. With an increase of acetonitrile content, the retention factor of CGA was increased on the MIP. In addition to shape recognition, hydrophilic interactions seem to work for the recognition of CGA on the MIP. The MIP had a specific molecular-recognition ability for CGA, while other related compounds, such as caffeic acid, gallic acid, protocatechuic acid and vanillic acid, could not be recognized by the MIP. Furthermore, the MIP for CGA was successfully applied for extraction of CGA in the leaves of Eucommia ulmodies.
Asunto(s)
Ácido Clorogénico/química , Eucommiaceae/química , Impresión Molecular/métodos , Polímeros/química , Acetonitrilos/química , Sitios de Unión , Ácidos Cafeicos/química , Técnicas de Química Analítica , Dimetilsulfóxido/química , Ácido Gálico/química , Interacciones Hidrofóbicas e Hidrofílicas , Hidroxibenzoatos/química , Metanol/química , Microscopía Electrónica de Rastreo , Microesferas , Nitrógeno/química , Hojas de la Planta/química , Porosidad , Unión Proteica , Solventes/química , Ácido Vanílico/química , Agua/químicaRESUMEN
Molecularly imprinted polymers (MIPs) for creatinine were prepared by modified precipitation polymerization using methacrylic acid as a functional monomer and divinylbenzene as a crosslinker. The prepared MIPs were monodispersed with a narrow particle size distribution. Binding experiments and Scatchard analyses revealed that two classes of binding sites, high- and low-affinity sites, were formed on the MIPs. The retention and molecular-recognition properties of the MIPs were evaluated by hydrophilic interaction chromatography using a mixture of ammonium acetate buffer and acetonitrile as a mobile phase. With an increase of acetonitrile content, the retention factor of creatinine was increased on the MIP. In addition to shape recognition, hydrophilic interactions seemed to enhance the recognition of creatinine on the MIP. The MIPs' molecular-recognition ability was specific for creatinine; the structurally related compounds such as hydantoin, 1-methylhydantoin, 2-pyrrolidone, N-hydroxysuccinimide and creatine were not recognized. Furthermore, the creatinine concentrations in human serum and urine were successfully determined by direct injection of the deproteinized serum and diluted urine samples onto the MIP.
Asunto(s)
Creatinina/análisis , Impresión Molecular , Polímeros/química , Precipitación Química , Creatinina/química , Humanos , PolimerizacionRESUMEN
A monodispersed molecularly imprinted polymer (MIP) for creatinine was prepared by modified precipitation polymerization. The retention and molecular-recognition properties of the prepared MIP were evaluated by the hydrophilic interaction chromatography mode using a mixture of ammonium acetate buffer and acetonitrile as a mobile phase in liquid chromatography. The MIP had a specific recognition ability for creatinine, while other structurally related compounds, such as hydantoin, 1-methylhydantoin, 2-pyrrolidone, N-hydroxysuccinimide and creatine, could not be recognized on the MIP. In addition to shape recognition, hydrophilic interactions could work for the recognition of creatinine on the MIP.
Asunto(s)
Creatinina/química , Impresión Molecular/métodos , Polímeros/química , Acetatos/química , Acetonitrilos/química , Tampones (Química) , Técnicas de Química Analítica/métodos , Creatina/química , Humanos , Hidantoínas/química , Cinética , Microscopía Electrónica de Rastreo/métodos , Modelos Químicos , Pirrolidinonas/química , Succinimidas/química , Factores de TiempoRESUMEN
1. Atherosclerosis is commonly observed in obesity. Obese atherosclerosis-prone animals may be a promising tool for understanding the pathophysiology of obesity-associated atherosclerosis. However, most rat strains are resistant to atherosclerosis. The aim of the present study was to assess the susceptibility of two obese hypertensive rat models, namely SHRSP.Z-Lepr(fa) /IzmDmcr rats (SHRSP-fatty) and SHR.Cg-Lepr(cp) /NDmcr rats (SHR-cp), to arterial lipid deposition, an initial stage of atherosclerosis, by comparing these strains with non-obese stroke-prone spontaneously hypertensive rats (SHRSP). 2. Eight-week-old male SHRSP, SHRSP-fatty and SHR-cp were fed a high-fat and high-cholesterol diet containing 20% palm oil, 5% cholesterol and 2% cholic acid for 5weeks. Bodyweight, blood pressure and fasting serum levels of total cholesterol and triglycerides were measured in 12-week-old rats. Oil red O staining was used to visualize lipid deposition in the mesenteric artery. 3. The bodyweight of 12-week-old SHRSP-fatty and SHR-cp was higher than that of SHRSP (P<0.005). Systolic blood pressure in SHRSP and SHRSP-fatty was higher than in SHR-cp (P<0.005). Serum total cholesterol and triglyceride levels were elevated in SHRSP-fatty (P<0.005) and SHR-cp (P<0.05) compared with levels in SHRSP. Lipid deposition in the mesenteric artery was significantly greater in SHRSP-fatty than in SHRSP (37.7±4.9 vs 13.1±2.8%, respectively; P<0.005), but markedly reduced in SHR-cp (1.8±0.4%; P<0.05). 4. The results of the present study indicate that SHRSP-fatty are highly susceptible to arterial lipid deposition, whereas SHR-cp are resistant. Thus, SHRSP-fatty may be a useful obese rat model in which to investigate atherosclerotic processes.