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1.
Molecules ; 25(13)2020 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-32640706

RESUMEN

A comprehensive linear gradient solvent system for centrifugal partition chromatography (CPC) was developed for the bioassay-guided isolation of natural compounds. The gradient solvent system consisted of three different ternary biphasic solvents types: n-hexane-acetonitrile-water (10:2:8, v/v), ethyl acetate-acetonitrile-water (10:2:8, v/v), and water-saturated n-butanol-acetonitrile-water (10:2:8, v/v). The lower phase of the n-hexane-acetonitrile-water (10:2:8, v/v) was used as the stationary phase, while its upper phase, as well as ethyl acetate-acetonitrile-water (10:2:8), and water-saturated n-butanol-acetonitrile-water (10:2:8, v/v) were pumped to generate a linear gradient elution, increasing the mobile phase polarity. We used the gradient CPC to identify antioxidant response elements (AREs), inducing compounds from Centipeda minima, using an ARE-luciferase assay in HepG2 cells, which led to the purification of the active molecules 3-methoxyquercetin and brevilin A. The developed CPC solvent systems allow the separation and isolation of compounds with a wide polarity range, allowing active molecule identification in the complex crude extract of natural products.


Asunto(s)
Asteraceae/química , Cromatografía Liquida/métodos , Distribución en Contracorriente/métodos , Extractos Vegetales/análisis , Solventes/química , 1-Butanol/química , Acetatos/química , Acetonitrilos/química , Elementos de Respuesta Antioxidante/efectos de los fármacos , Bioensayo , Supervivencia Celular/efectos de los fármacos , Cromatografía Liquida/instrumentación , Distribución en Contracorriente/instrumentación , Crotonatos/aislamiento & purificación , Genes Reporteros/efectos de los fármacos , Células Hep G2 , Hexanos/química , Humanos , Luciferasas/química , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Quercetina/análogos & derivados , Quercetina/aislamiento & purificación , Sesquiterpenos/aislamiento & purificación , Agua/química
2.
J Sep Sci ; 42(11): 2080-2088, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31087537

RESUMEN

In this work, a continuous high-speed countercurrent chromatography method has been developed on the basis of elution-extrusion mode and this method was successfully applied to the separation of maslinic and oleanolic acid from the extract of olive pulp. In the process of 'elution', the sample solution was continuously loaded into the column and the maslinic acid was steadily eluted out in this step while highly retained oleanlic acid always stayed in the column. In the process of 'extrusion', the oleanlic acid was pushed out of the column with the stationary phase. In this way, we achieved a large sample loading. A total of 120 mL sample solution (about 89.55% of the column volume) which contains 600 mg olive pulp extract was pumped in the apparatus by a constant-flow pump and the maslinic and oleanolic acids were largely separated within 120 min. Both of these two compounds presented high yields and high purities (271.6 mg for maslinic acid with 86.7% and 83.9 mg oleanolic acids with 83.4%).


Asunto(s)
Distribución en Contracorriente/métodos , Olea/química , Ácido Oleanólico/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Triterpenos/aislamiento & purificación , Residuos/análisis , Distribución en Contracorriente/instrumentación , Frutas/química , Ácido Oleanólico/análisis , Extractos Vegetales/análisis , Triterpenos/análisis
3.
Mar Drugs ; 17(4)2019 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-30987394

RESUMEN

Phlorotannins are polyphenolic metabolites of marine brown algae that have been shown to possess health-beneficial biological activities. An efficient approach using a combination of high-speed counter-current chromatography (HSCCC) and size exclusion chromatography with a Sephadex LH-20 has been successfully developed for the isolation and purification of a neuroprotective phlorotannin, eckmaxol, from leaves of the marine brown algae, Ecklonia maxima. The phlorotannin of interest, eckmaxol, was isolated with purity >95% by HSCCC using an optimized solvent system composed of n-hexane-ethyl acetate-methanol-water (2:8:3:7, v/v/v/v) after Sephadex LH-20 size exclusion chromatography. This compound was successfully purified in the quantity of 5.2 mg from 0.3 kg of the E. maxima crude organic extract. The structure of eckmaxol was identified and assigned by NMR spectroscopic and mass spectrometric analyses. The purification method developed for eckmaxol will facilitate the further investigation and development of this neuroprotective agent as a drug lead or pharmacological probe. Furthermore, it is suggested that the combination of HSCCC and size exclusion chromatography could be more widely applied for the isolation and purification of phlorotannins from marine algae.


Asunto(s)
Organismos Acuáticos/química , Fraccionamiento Químico/métodos , Fármacos Neuroprotectores/aislamiento & purificación , Phaeophyceae/química , Polifenoles/aislamiento & purificación , Fraccionamiento Químico/instrumentación , Química Farmacéutica/métodos , Cromatografía en Gel/instrumentación , Cromatografía en Gel/métodos , Cromatografía Líquida de Alta Presión/instrumentación , Cromatografía Líquida de Alta Presión/métodos , Distribución en Contracorriente/instrumentación , Distribución en Contracorriente/métodos , Espectroscopía de Resonancia Magnética , Solventes/química , Espectrometría de Masa por Ionización de Electrospray/instrumentación , Espectrometría de Masa por Ionización de Electrospray/métodos
4.
J Sep Sci ; 41(18): 3607-3613, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30073789

RESUMEN

Extraction is the most important step in the purification of bioactive compounds from natural products. This study introduces a simple online extraction strategy coupled with high-speed counter-current chromatography for efficient extraction and purification of bioactive components from solid natural products. For online extraction strategy, 1.0 g of ground Mangnolia officinalis or Piper nigrum was loaded into a guard column, which was then positioned on the manual injection valve instead of the sample loop. Bioactive components were directly extracted by the mobile phase of high-speed counter-current chromatography, and then transferred into high-speed counter-current chromatography for purification. In addition, the compatibility of the developed methodology for direct purification of bioactive components from fresh M. officinalis was successfully demonstrated. Obviously, in comparison with traditional offline heat-reflux extraction, online extraction avoided the instrument, time, solvent, and energy consumption, and purified two phenolic compounds (honokiol and magnolol) from M. officinalis and three alkaloids (piperyline, piperine, and piperanine) from P. nigrum with high extraction efficiency. The superiority of the developed methodology is to establish an easy, rapid, and efficient technique for the purification of a wide variety of bioactive components from solid natural products.


Asunto(s)
Productos Biológicos/aislamiento & purificación , Piper nigrum/química , Extractos Vegetales/aislamiento & purificación , Productos Biológicos/química , Distribución en Contracorriente/instrumentación , Estructura Molecular , Extractos Vegetales/química
5.
J Sep Sci ; 41(13): 2828-2836, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29664172

RESUMEN

Recycling countercurrent chromatography was successfully applied to the resolution of 2-(4-bromomethylphenyl)propionic acid, a key synthetic intermediate for synthesis of nonsteroidal anti-inflammatory drug loxoprofen, using hydroxypropyl-ß-cyclodextrin as chiral selector. The two-phase solvent system composed of n-hexane/n-butyl acetate/0.1 mol/L citrate buffer solution with pH 2.4 (8:2:10, v/v/v) was selected. Influence factors for the enantioseparation were optimized, including type of substituted ß-cyclodextrin, concentration of hydroxypropyl-ß-cyclodextrin, separation temperature, and pH of aqueous phase. Under optimized separation conditions, 50 mg of 2-(4-bromomethylphenyl)propionic acid was enantioseparated using preparative recycling countercurrent chromatography. Technical details for recycling elution mode were discussed. The purities of both the S and R enantiomers were over 99.0% as determined by high-performance liquid chromatography. The enantiomeric excess of the S and R enantiomers reached 98.0%. The recovery of the enantiomers from eluted fractions was 40.8-65.6%, yielding 16.4 mg of the S enantiomer and 10.2 mg of the R enantiomer. At the same time, we attempted to enantioseparate the anti-inflammatory drug loxoprofen by countercurrent chromatography and high-performance liquid chromatography using a chiral mobile phase additive. However, no successful enantioseparation was achieved so far.


Asunto(s)
Antiinflamatorios/química , Distribución en Contracorriente/métodos , Fenilpropionatos/química , 2-Hidroxipropil-beta-Ciclodextrina/química , Cromatografía Líquida de Alta Presión , Distribución en Contracorriente/instrumentación , Propionatos , Estereoisomerismo
6.
Molecules ; 22(5)2017 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-28486427

RESUMEN

In this work, flavonoid fraction from the leaves of Crataegus pinnatifida was separated into its seven main constituents using a combination of HSCCC coupled with pre-HPLC. In the first step, the total flavonoid extract was subjected to HSCCC with a two-solvent system of chloroform/methanol/water/n-butanol (4:3:2:1.5, v/v), yielding four pure compounds, namely (-)-epicatechin (1), quercetin-3-O-(2,6-di-α-l-rhamnopyranosyl)-ß-d-galactopyranoside (2), 4''-O-glucosylvitexin (3) and 2''-O-rhamnosylvitexin (4) as well as a mixture of three further flavonoids. An extrusion mode was used to rapidly separate quercetin-3-O-(2,6-di-α-l-rhamnopyranosyl)-ß-d-galactopyranoside with a big KD-value. In the second step, the mixture that resulted from HSCCC was separated by pre-HPLC, resulting in three pure compounds including: vitexin (5), hyperoside (6) and isoquercitrin (7). The purities of the isolated compounds were established to be over 98%, as determined by HPLC. The structures of these seven flavonoids were elucidated by ESI-MS and NMR spectroscopic analyses.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Distribución en Contracorriente/métodos , Crataegus/química , Flavonoides/aislamiento & purificación , Extractos Vegetales/química , Hojas de la Planta/química , Apigenina/aislamiento & purificación , Catequina/aislamiento & purificación , Distribución en Contracorriente/instrumentación , Flavonoides/clasificación , Glicósidos/aislamiento & purificación , Quercetina/análogos & derivados , Quercetina/aislamiento & purificación , Solventes
7.
Anal Chem ; 87(20): 10172-7, 2015 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-26383896

RESUMEN

Countercurrent chromatography (CCC) is a separation technique based on the liquid-liquid partitioning of compounds between the two phases of a biphasic solvent system. Limitations in the separation efficiency and peak capacity of one-dimensional (1D) CCC often result in insufficiently resolved peaks. Therefore, partially resolved peak fractions have to be rechromatographed in order to improve the yield and purity. Additional solvent evaporation steps can be circumvented by the application of two-dimensional CCC (2D CCC). Existing 2D CCC configurations are based on the linking of two CCC instruments which are not readily available in every laboratory. In this study, we introduce a technical improvement which allows performing multiple heart-cuts and 2D CCC separations with one instrument which has up to four independent coils, one pump, and one detector. For this purpose, we modified a commercially available CCC system by the addition of three six-port selection valves and a T-piece. The applicability of the 2D CCC system was shown under overloading conditions with eight alkyl hydroxybenzoates with nonideal conditions. We used two solvent systems which were hydrodynamically compatible and which showed different selectively characteristics with regard to the compounds. Four unresolved compounds in the first dimension were baseline resolved by means of the heart-cut technique, in which between 4 and 9 mL of the flow from coil 1 was transferred to coil 2. Three successive heart-cuts were performed that led to baseline resolution of unresolved compounds in the first dimension. The obtained recovery rates were 94-100%, and the purities of the compounds as determined by GC/MS were 90-100%.


Asunto(s)
Distribución en Contracorriente/instrumentación , Distribución en Contracorriente/métodos , Hidroxibenzoatos/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas/instrumentación , Hidrodinámica , Hidroxibenzoatos/química , Solventes/química
8.
Phytochem Anal ; 26(6): 444-53, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26103066

RESUMEN

INTRODUCTION: The dried seeds of Iris lactea have been used in traditional Chinese medicine. Previous studies have been focused on irisquinones while other chemical components are rarely reported. OBJECTIVE: To establish an efficient high-speed counter-current chromatography (HSCCC) separation method with continuous sample load (CSL) and double-pump balancing (DPB) mode to isolate proanthocyanidins from I. lactea. METHODS: Firstly, an ethyl acetate extract of I. lactea was pre-fractionated by silica column chromatography for the enrichment of proanthocyanidins. Secondly, the enriched proanthocyanidins sample (EPS) was further fractionated by HSCCC with a two-phase solvent system ethyl acetate:n-butanol:water (9:1:10, v/v/v) using DPB mode. The flow rate of the two phases was 2.2 mL/min, the revolution speed was 900 rpm, the separation temperature was 30 °C and the detection wavelength was 280 nm. Finally, the structures of the three isolated proanthocyanidins were elucidated by spectroscopic methods and compared with published data. RESULTS: Under the optimized conditions, 600 mg of the EPS with six continuous injections (100 mg/time) was fractionated, yielding 57 mg of prodelphinidin B3, 198 mg of procyanidin B3, and 162 mg of procyanidin B1, at purities of 97.2%, 98.1% and 97.3%, respectively. CONCLUSIONS: The HSCCC separation method with CSL and DPB proved to be rapid, convenient and economical, constituting an efficient strategy for the isolation of proanthocyanidins.


Asunto(s)
Distribución en Contracorriente/métodos , Género Iris/química , Proantocianidinas/aislamiento & purificación , Semillas/química , Distribución en Contracorriente/economía , Distribución en Contracorriente/instrumentación
9.
Anal Bioanal Chem ; 406(4): 957-69, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23748592

RESUMEN

Countercurrent chromatography (CCC) is an attractive separation method because the analytes are partitioned between two immiscible liquid phases avoiding problems related to solid stationary phase. In recent years, this technique has made great progress in separation power and detection potential. This review describes coupling strategies involving high speed CCC (HSCCC) or centrifugal partition chromatography (CPC). It includes on-line extraction-isolation, hyphenation with mass spectrometry (MS) and nuclear magnetic resonance (NMR) detectors, multidimensional CCC (MDCCC), two-dimensional CCC (2D-CCC), on-line coupling with liquid chromatography (LC), and biological tests, and innovative off-line developments. The basic principles of each method are presented and applications are summarized.


Asunto(s)
Centrifugación/tendencias , Distribución en Contracorriente/tendencias , Animales , Centrifugación/instrumentación , Centrifugación/métodos , Cromoterapia/instrumentación , Cromoterapia/métodos , Cromoterapia/tendencias , Distribución en Contracorriente/instrumentación , Distribución en Contracorriente/métodos , Humanos , Péptidos/análisis , Péptidos/aislamiento & purificación , Extractos Vegetales/análisis , Extractos Vegetales/aislamiento & purificación
10.
J Sep Sci ; 37(23): 3443-50, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25215879

RESUMEN

Recycling high-speed counter-current chromatography was successfully applied to the preparative separation of oxybutynin enantiomers. The two-phase solvent system consisted of n-hexane, methyl tert-butyl ether, and 0.1 mol/L phosphate buffer solution (pH = 5.0) with the volume ratio of 6:4:10. Hydroxypropyl-ß-cyclodextrin was employed as the chiral selector. The influence of factors on the chiral separation process, including the concentration of chiral selector, the equilibrium temperature, the pH value of the aqueous phase were investigated. Under optimum separation conditions, 15 mg of oxybutynin racemate was separated with the purities of both the enantiomers over 96.5% determined by high-performance liquid chromatography. Recovery for the target compounds reached 80-82% yielding 6.00 mg of (R)-oxybutynin and 6.15 mg of (S)-oxybutynin. Technical details for recycling elution mode were discussed.


Asunto(s)
Ácidos Mandélicos/química , Ácidos Mandélicos/aislamiento & purificación , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Distribución en Contracorriente/instrumentación , Distribución en Contracorriente/métodos , Estereoisomerismo
11.
J Sep Sci ; 37(1-2): 135-42, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24243884

RESUMEN

Normal-phase high-performance counter-current chromatography (HPCCC) is used to obtain a preliminary fractionation of components in dissolved organic matter (DOM) from a freshwater source. The HPCCC solvent system involved a normal-phase approach with water/methanol (1:1) as the lower stationary phase and hexane/ethyl acetate (1:1) as the upper mobile phase. The critical experiment parameters were optimised: revolution speed 1800 rpm and flow rate 0.15 mL/min. Under these conditions 50 µL of a 0.50 mg/mL DOM solution was loaded. The detection wavelength was monitored at 330 nm in order to isolate the main portion of DOM, which includes substances such as carboxyl-rich alicyclic molecules. By optimising this system it was possible to isolate materials that, according to GC-MS, can be related to molecules with an analogous structural background. Where fraction analysis was not suitable for GC-MS, RP-HPLC with UV absorbance detection was used, showing unique chromatograms for each fraction at both 210 and 330 nm.


Asunto(s)
Distribución en Contracorriente/métodos , Agua Dulce/química , Compuestos Orgánicos/aislamiento & purificación , Contaminantes Químicos del Agua/aislamiento & purificación , Distribución en Contracorriente/instrumentación , Compuestos Orgánicos/química , Solubilidad , Contaminantes Químicos del Agua/química
12.
J Sep Sci ; 37(23): 3587-94, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25223791

RESUMEN

A separation method using counter current chromatography coupled with an evaporative light-scattering detection system was developed to purify five triterpenoid saponins from the roots of Bupleurum falcatum. The methanol extract was loaded onto a Diaion® HP20 column and fractionated by a methanol and water gradient elution. The saikosaponin-enriched fraction was obtained by elution with 100% methanol. The two-phase solvent systems used for separation were composed of chloroform/methanol/isopropanol/water at a volume ratio of 60:60:1:60 and 6:6:1:6. The relationship between the isopropanol ratio of each phase and the partition coefficients of the target compounds was investigated by calculating partition coefficient by high-performance liquid chromatography and measuring the accurate composition of each phase by (1) H NMR spectroscopy. Each fraction obtained was collected and dried, which yielded the following five saikosaponins from 700 mg of injected sample: saikosaponin B1 (8.7 mg), saikosaponin A (86 mg), saikosaponin B3 (17 mg), saikosaponin B2 (41 mg), and saikosaponin C (33 mg). Saikosaponin A showed the most potent cytotoxicity against human cancer cells (gastric cancer, AGS cells; breast cancer, MCF-7 cells; and hepatoma, HepG2 cells) after 24 h. The IC50 values for the above three cell types were 34.6, 33.3, and 23.4 µmol/L, respectively.


Asunto(s)
Antineoplásicos Fitogénicos/aislamiento & purificación , Bupleurum/química , Distribución en Contracorriente/métodos , Medicamentos Herbarios Chinos/aislamiento & purificación , Triterpenos/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/farmacología , Proliferación Celular/efectos de los fármacos , Distribución en Contracorriente/instrumentación , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Humanos , Células MCF-7 , Raíces de Plantas/química , Triterpenos/química , Triterpenos/farmacología
13.
J Chromatogr A ; 1728: 465031, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-38815477

RESUMEN

In counter-current chromatography (CCC), linear scale-up is an ideal amplification strategy. However, when transferring from analytical to predictable preparative processes with high throughput, linear scale-up would be challenging due to limitations imposed by differences in instrument parameters, such as gravitational forces, tubing cross-section area, tubing length, column volume and flow rate. Some effective scale-up strategies have been studied for different instrument parameters, but so far, these scale-up works have only been tested on standard circular (SC) tubing. The previous research of our group found that rectangular horizontal (RH) tubing can double the separation efficiency compared with conventional SC tubing, and has industrial production potential. This paper used the separation of tilianin from Dracocephalum moldavica L. as an example to demonstrate how to scale up the optimized process from analytical SC tubing to preparative RH tubing. After systematic optimization of solvent systems, sample concentration and flow rate on the analytical CCC, the optimized parameters obtained were successfully transferred to the preparative CCC. The results showed that a crude sample of 2.07 g was successfully separated using a solvent system of n-hexane - ethyl acetate - ethanol - water (1:4:1:5, v/v/v/v) in reversed phase mode, and the three consecutive separations produced a total of 380 mg tilianin in 75 min with high purities of 98.3%, as analyzed by HPLC. The total throughput achieved from the analytical to semi-preparative scale was improved by 138 times (from 12 mg/h to 1.66 g/h), while the column volume was increased by only 46.5 times (from 15.5 mL to 720 mL). This is the successful application of CCC for the separation and purification of tilianin. Given that SC tubing is the traditional configuration for CCC columns, this study is a necessary step to prove the applicability of RH tubing columns for routine use and potential large-scale industrial applications.


Asunto(s)
Distribución en Contracorriente , Distribución en Contracorriente/métodos , Distribución en Contracorriente/instrumentación , Glicósidos/aislamiento & purificación , Glicósidos/análisis , Glicósidos/química , Piranos/aislamiento & purificación , Piranos/análisis , Solventes/química , Hexanos/química , Lamiaceae/química , Cromatografía Líquida de Alta Presión/instrumentación , Cromatografía Líquida de Alta Presión/métodos , Etanol/química , Acetatos/química , Flavonoides
14.
J Sep Sci ; 36(12): 2035-42, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23568858

RESUMEN

This work concentrates on extending the utilization of multiple dual mode (MDM) counter-current chromatography in chiral separations. Two aromatic acids, 2-(6-methoxy-2-naphthyl)propionic acid (NAP) and 2-phenylpropionic acid (2-PPA), were enantioseparated by MDM counter-current chromatography using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as chiral selector. The two-phase solvent systems consisting of n-hexane/ethyl acetate 0.1 mol/L phosphate buffer pH 2.67 containing 0.1 mol/L HP-ß-CD (7.5:2.5:10 for NAP and 7:3:10 for 2-PPA, v/v/v) were used. Conventional MDM and modified MDM were compared according to peak resolution under current separation mechanism. The influence of elution time after the first-phase inversion and number of cycles for MDM were investigated. Peak resolution of NAP and 2-PPA increased from 0.62 to 1.05 and 0.72 to 0.84, respectively, using optimized MDM conditions. Being an alternative elution method for counter-current chromatography, MDM elution greatly improved peak resolution in chiral separations.


Asunto(s)
Ácidos Carbocíclicos/química , Ácidos Carbocíclicos/aislamiento & purificación , Distribución en Contracorriente/métodos , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Distribución en Contracorriente/instrumentación , Estereoisomerismo
15.
J Sep Sci ; 36(2): 407-13, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23335460

RESUMEN

pH-zone-refining centrifugal partition chromatography was successively applied in the large-scale separation of close R(f) antipsychotic indole alkaloids directly from CHCl(3) fraction of Rauwolfia tetraphylla leaves. Two experiments with increasing mass from 500 mg to 3 g of crude alkaloid extracts (1C) of R. tetraphylla were carried out in normal-displacement mode using a two-phase solvent system composed of methyl tert-butyl ether/ACN/water (4:1:5, v/v/v) where HCl (12 mM) was added to the lower aqueous stationary phase as a retainer and triethylamine (5 mM) to the organic mobile phase as an eluter. The two centrifugal partition chromatography separations afforded a total of 162.6 mg of 10-methoxytetrahydroalstonine (1) and 296.5 mg of isoreserpiline (2) in 97% and 95.5% purity, respectively, along with a 400.9 mg mixture of α-yohimbine and reserpiline (3 and 4). Further, this mixture was resolved over medium pressure LC using TLC grade silica gel H (average particle size 10 µm), which afforded 160.4 mg of α-yohimbine (3) and 150.2 mg of reserpiline (4) in >95% purities. The purity of the isolated antipsychotic alkaloids was analyzed by high-performance LC and their structures were characterized on the basis of their 1D, 2D NMR and electrospray ionization-mass spectroscopic data.


Asunto(s)
Alcaloides/aislamiento & purificación , Antipsicóticos/aislamiento & purificación , Distribución en Contracorriente/métodos , Extractos Vegetales/aislamiento & purificación , Rauwolfia/química , Distribución en Contracorriente/instrumentación , Concentración de Iones de Hidrógeno
16.
J Sep Sci ; 36(20): 3338-44, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23939907

RESUMEN

An off-line 2D high-speed counter-current chromatography technique in preparative scale has been successfully applied to separate and purify the main compounds from the ethyl acetate extract of Desmodium styracifolium. A two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water at an optimized volume ratio of 1:2:1:2 v/v/v/v was used. Conventional high-speed counter-current chromatography was used as the first dimension, and the upper phase of the solvent system was used as the stationary phase in the head-to-tail elution mode at a flow rate of 2.0 mL/min and a rotation speed of 900 rpm. Recycling high-speed counter-current chromatography served as the second dimension to separate an impure fraction of the first dimension. A total of four well-separated substances including vanillic acid (1), ß-sitosterol (2), formononetin (3), and aromadendrin (4) were obtained, and their purities and structures were identified by HPLC-MS and (1) H NMR spectroscopy. The results illustrated that off-line 2D high-speed counter-current chromatography is an effective way to isolate compounds in complex samples.


Asunto(s)
Distribución en Contracorriente/métodos , Fabaceae/química , Extractos Vegetales/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Distribución en Contracorriente/instrumentación , Espectroscopía de Resonancia Magnética , Extractos Vegetales/química
17.
J Sep Sci ; 36(14): 2253-9, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23686916

RESUMEN

This paper describes the isolation of flavonoids and other aromatic compounds from an ethyl acetate extract of leaves of Siparuna glycycarpa using stepwise elution counter-current chromatography (CCC). The elution profile yielded the following compounds: diglycosylated flavonoids, quercetin 3-O-rutinoside and quercetin 7-O-rutinoside, followed by monoglycosylated flavonoids, kaempferol-3-O-ß-glucopyranoside, kaempferol-3-O-ß-rhamnopiranoside, kaempferol-3-O-ß-6''(p-coumaroyl) glucopyranoside, and quercetin-3-O-ß-glucopyranoside, and then free phenolics, protocatechuic acid, and 2',6'-dihydroxy-4, 4'-dimethoxydihydrochalcone, which shows that this type of elution covers a broader range of polarity than the traditional isocratic mode. This makes it more suitable to perform separations of mixtures containing large differences in hydrophobicity. A GC analysis of a blank CCC run was performed to determine if changes in the mobile phase composition affect the chromatographic process. Results showed a gradual variation of the composition of the mobile phase emerging after the step gradient, favoring the selectivity of the solvent system.


Asunto(s)
Distribución en Contracorriente/métodos , Flavonoides/aislamiento & purificación , Magnoliopsida/química , Extractos Vegetales/aislamiento & purificación , Distribución en Contracorriente/instrumentación , Flavonoides/química , Estructura Molecular , Extractos Vegetales/química , Hojas de la Planta/química
18.
Phytochem Anal ; 24(6): 603-7, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23722877

RESUMEN

INTRODUCTION: Lignans and flavonols are the primary constituents of Sinopodophyllum emodi and have been used as cathartic, anthelmintic, chemotherapeutic and anti-hypertensive compounds. Although these compounds have been isolated, there have been no reports on the separation of 4'-demethyl podophyllotoxin, podophyllotoxin, deoxypodophyllotoxin and kaempferol in one step by medium-pressure liquid chromatography (MPLC) and high-speed counter-current chromatography (HSCCC). OBJECTIVE: Development of an efficient method for the preparative separation and purification of three lignans and one flavonol from S. emodi. METHODS: The precipitate of crude extracts was first separated by MPLC into four parts, numbered GJ-1, GJ-2, GJ-3 and GJ-4. GJ-1 was separated and purified by HSCCC using a solvent system composed of n-hexane:ethyl acetate:methanol:water (1.75:1.5:1:0.75, v/v/v/v). The purities of the target compounds were assessed using high-performance liquid chromatography (HPLC) and chemical structures were identified by (1) H-NMR and (13) C-NMR. RESULTS: The HSCCC and MPLC methods were successfully used for the preparative separation and purification of 4'-demethyl podophyllotoxin (8.5 mg, 92.4%), podophyllotoxin (40.1 mg, 92.1%), deoxypodophyllotoxin (4.6 mg, 98.1%), and kaempferol (1.6 mg, 96.7%) from a 100 mg sample. CONCLUSION: Three lignans (4'-demethyl podophyllotoxin, podophyllotoxin, deoxypodophyllotoxin) and one flavonol (kaempferol) were successfully isolated by HSCCC and MPLC in one step.


Asunto(s)
Berberidaceae/química , Cromatografía Liquida/métodos , Distribución en Contracorriente/métodos , Flavonoles/aislamiento & purificación , Lignanos/aislamiento & purificación , Cromatografía Liquida/instrumentación , Distribución en Contracorriente/instrumentación , Flavonoles/química , Lignanos/química , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular
19.
J Sep Sci ; 35(12): 1462-9, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22740255

RESUMEN

A new model of solvent gradients selection was rationally developed for the preparative separation of target compounds. The solvent gradients were selected based on a three-stage screening process where stationary phase retention was ensured by introducing a new parameter termed as the phase ratio. The phase ratio was calculated after mixing the upper phase of a solvent system with the lower phase of a different solvent system (1:1, v/v). The developed model was applied to the one-step separation of eight ginsenosides from Panax ginseng. Three gradients were selected on the basis of new model and eight ginsenosides, Rb(1), Rb(2), Rc, Rd, Re, Rg(1), Rf, and Rh(1), were efficiently separated by high-speed counter-current chromatography coupled with evaporative light scattering detector. The structures of all compounds were characterized by electrospray-ionization mass spectrometry and nuclear magnetic resonance spectroscopy.


Asunto(s)
Distribución en Contracorriente/métodos , Ginsenósidos/aislamiento & purificación , Panax/química , Extractos Vegetales/aislamiento & purificación , Distribución en Contracorriente/instrumentación , Solventes/química
20.
J Sep Sci ; 35(1): 159-65, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22084024

RESUMEN

The first preparative separation of a flavonoid sulphate isorhamnetin 3-sulphate from Flaveria bidentis (L.) Kuntze by counter-current chromatography (CCC) was presented. Two kinds of solvent systems were used. A conventional organic/aqueous solvent system n-butanol-ethyl acetate-water (4:1:5, v/v) was used, yielding isorhamnetin 3-sulphate 2.0 mg with a purity of 93.4% from 83 mg of pre-enriched crude extract obtained from 553 mg ethanol extract by macroporous resin. A one-component organic/salt-containing system composed of n-butanol-0.25% sodium chloride aqueous solution (1:1, v/v) was also used, and the LC column packed with macroporous resin has been employed for desalination of the target compound purified from CCC. As a result, 2.1 mg of isorhamnetin 3-sulphate with a purity of over 97% has been isolated from 402 mg of crude extract without pre-enrichment. Compared with the conventional organic/aqueous system, the one-component organic/salt-containing aqueous system was more suitable for the separation of isorhamnetin 3-sulphate, and purer target compound was obtained from the crude extract without pre-enrichment using the new solvent system. The chemical structure was confirmed by ESI-MS and (1)H, (13)C NMR. In summary, our results indicated that CCC using one-component organic/salt-containing aqueous solution is very promising and powerful for high-throughput purification of isorhamnetin 3-sulphate from Flaveria bidentis (L.) Kuntze.


Asunto(s)
Distribución en Contracorriente/métodos , Flaveria/química , Extractos Vegetales/aislamiento & purificación , Quercetina/análogos & derivados , Distribución en Contracorriente/instrumentación , Quercetina/análisis , Quercetina/aislamiento & purificación
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