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At least 829 records · Page 46Linked to original sources
PubMed2001

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine using high-speed counter-current chromatography.

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine was conducted using high-speed counter-current chromatography. Among seven components obtained our studies focused two metabolites, i.e. (-)-epicatechin and D,L-catechin. The specific radioactivity of (-)-epicatechin was 212.01 KBq/mg, amounting to 8.5% of the total radioactivity of ethyl acetate extract while that of D,L-catechin was 1.0006 MBq/mg or 5.4% of the total.

Carbon Radioisotopes↗
PubMed2001

Evaluation of different tubing geometries for high-speed counter-current chromatography.

Different tubing geometries were evaluated for use in high-speed counter-current chromatography. Standard round tubing was compared to rectangular and twisted rectangular tubing. The number of theoretical plates for a standard anthocyanin mixture from black currant was determined for each experiment. The results of twisted rectangular tubing were superior to a standard setup.

Anthocyanins↗
PubMed2001

Preparative isolation and purification of astaxanthin from the microalga Chlorococcum sp. by high-speed counter-current chromatography.

High-speed counter-current chromatography was applied to the isolation and purification of astaxanthin from microalgae. The crude astaxanthin was obtained by extraction with organic solvents after the astaxanthin esters were saponified. Preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (5:5:6.5:3, v/v) was successfully performed yielding astaxanthin at 97% purity from 250 mg of the crude extract in a one-step separation.

Chlorophyta↗
PubMed2001

Preparative isolation and purification of six diterpenoids from the Chinese medicinal plant Salvia miltiorrhiza by high-speed counter-current chromatography.

A high-speed counter-current chromatography (HSCCC) method was developed for the preparative separation and purification of six diterpenoids. dihydrotanshinone I, cryptotanshinone, methylenetanshiquinone, tanshinone I, tanshinone IIA and danshenxinkun B from the Chinese medicinal plant Salvia miltiorrhiza Bunge. The crude diterpenoids were obtained by extraction with ethanol-n-hexane (1:1, v/v) from S. miltiorrhiza Bunge. Preparative HSCCC with the two-phase solvent systems A composed of n-hexane-ethanol-water (10:5.5:4.5, v/v) and B composed of n-hexane-ethanol-water (10:7:3, v/v) was successfully performed in a stepwise elution yielding six relatively pure diterpenoids from 300 mg of the crude extract in a single run. The purities of dihydrotanshinone I, cryptotanshinone, methylenetanshiquinone, tanshinone I, tanshinone IIA and danshenxinkun B were 88.1, 98.8, 97.6, 93.5, 96.8 and 94.3%, respectively.

Chromatography, High Pressure Liquid↗
PubMed2001

Application of coil centrifugal counter-current chromatography to the separation of macrolide antibiotic analogues III. Effects of flow-rate, mass load and rotation speed on the peak resolution.

As the third part of our methodology studies on the application of centrifugal counter-current chromatography to the preparative separation of macrolide antibiotic analogues, we have investigated the effects of various parameters on the retention of stationary phase and peak resolution. Our results show that the retention percentage of the stationary phase has linear relationships with both flow-rate at 1 to 3 ml/min and rotation speed at 100 to 700 rpm, but their correlation coefficients are negative (-1.000) and positive (0.9821), respectively. The peak resolution (Rs) is inversely proportional to the flow-rate (Fr) and mass load (Ml), but directly proportional to the rotation speed (Rrev). Their correlation coefficients in linear regression for the preparative separation in laboratory scale are -0.981 to -1.000 for Rs=a+bFr at flow-rates of 1 to 3 ml/min, -0.929 to -0.993 for Rs=a+bMl at mass loads of 12.5 to 100 mg, and 0.975 to 0.998 for Rs=a+bRrev at rotation speeds of 300 to 700 rpm, respectively. Preparative separation of six very closely related macrolide antibiotics, which belong to ascomycin and rapamycin analogues, has also been successfully achieved under optimized conditions.

Anti-Bacterial Agents↗
PubMed2001

Versatile two-phase solvent system for alkaloid separation by high-speed counter-current chromatography.

In order to find a versatile high speed counter-current chromatography solvent system that can be used as a general prefractionation system for most alkaloids, the crude extracts of five Chinese traditional medicinal herbs, Cortex phellodendri, Semen strychni, green tea, Sophora flavescens ait, and Datura mete L. were resolved. All separations were performed only with a two-phase system composed of CHCl3-CH3OH-water (4:3:2). The water had different acidities controlled by adding NaH2PO4 or HCl to each sample. The fractionated components were identified by thin-layer chromatography, which confirmed this solvent system was versatile and very useful for the separation of alkaloids.

Alkaloids↗
PubMed2001

Separation and purification of isoflavones from a crude soybean extract by high-speed counter-current chromatography.

A set of isoflavones with a broad range of polarity including daidzin, glycitin, genistin, acetyldaidzin, glycitein, acetylgenistin and daidzein was separated from a crude soybean extract by high-speed counter-current chromatography using a two-step operation. Three solvent systems were used: chloroform-methanol-water (4:3:2, v/v); chloroform-methanol-n-butanol-water (4:3:0.5:2, v/v); and methyl tert.-butyl ether-tetrahydrofuran-0.5% aqueous trifluoroacetic acid (2:2:0.15:4, v/v). The first solvent system was used for separating less polar isoflavones and the second for more polar isoflavones by eluting the lower organic phase. Genistin and glycitin, which were only partially resolved in the chloroform system, were separated by the third solvent system. Each isolated component showed 98-99% purity as determined by high-performance liquid chromatography analysis. Their structures were identified by LC-MS.

Chromatography, High Pressure Liquid↗
PubMed2001

Application of analytical and preparative high-speed counter-current chromatography for separation of lycopene from crude extract of tomato paste.

Lycopene was isolated from 100 mg of crude extract of tomato paste containing about 9% of lycopene. Analytical high-speed counter-current chromatography (HSCCC) was first used for the systematic selection of the two-phase solvent system. Then preparative HSCCC separation was performed with a nonaqueous solvent system composed of n-hexane-dichloromethane-acetonitrile at an optimum volume ratio of 10:3.5:6.5. This yielded 8.6 mg of lycopene at over 98.5% purity as determined by HPLC analysis.

Carotenoids↗
PubMed2001

Preparative isolation and purification of salidroside from the Chinese medicinal plant Rhodiola sachalinensis by high-speed counter-current chromatography.

High-speed counter-current chromatography was applied to the isolation and purification of salidroside from the Chinese medicinal plant Rhodiola sachalinensis A. Bor. The crude salidroside was obtained by extraction with methanol from Rhodiola sachalinensis A. Bor. Preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-butanol-ethyl acetate-water (2:3:5, v/v) was successfully performed yielding salidroside (32 mg) at 98% purity from 250 mg of the crude extract in a one-step separation.

Chromatography, High Pressure Liquid↗
PubMed2001

Separation of WAP-8294A components, a novel anti-methicillin-resistant staphylococcus aureus antibiotic, using high-speed counter-current chromatography.

The WAP-8294A complex was isolated from the fermentation broth of Lysobacter sp. WAP-8294, whose major component, WAP-8294A2, showed a strong activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci in vitro, and also exhibited a potent activity against MRSA in vivo. The previous separation procedure using the conventional chromatographic methods was laborious and time-consuming, and the recovery of the desired compound was often unsatisfactory. In the present study, high-speed counter-current chromatography (HSCCC) was applied to the separation of the main components of the WAP-8294A complex. Due to the high polarity of the target compounds, we selected a hydrophilic two-phase solvent system composed of n-butanol-ethyl acetate-aqueous 0.005 M trifluoroacetic acid (1.25:3.75:5, v/v/v) which provided a suitable range of partition coefficient values for these compounds. Although the settling time of this solvent system was much longer than the optimum range, suggesting a low retention of the stationary phase under the standard experimental conditions, the separation was successfully performed at the low flow-rate of 0.5 ml/min. A sample size of 25 mg yielded pure fractions of three components (1-6 mg). The identification of each component was carried out by HPLC and fast atom bombardment mass spectrometry. The method will contribute to the clinical development of WAP-8294A2 as an anti-MRSA agent.

Countercurrent Distribution↗
PubMed2002

Preparative isolation and purification of salvianolic acid B from the Chinese medicinal plant Salvia miltiorrhiza by high-speed counter-current chromatography.

High-speed counter-current chromatography was applied to the isolation and purification of salvianolic acid B from the Chinese medicinal plant Salvia miltiorrhiza Bunge. The crude salvianolic acid B was obtained by extraction with ethanol-water from S. miltiorrhiza Bunge. Preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (3:7:1:9, v/v) was successfully performed yielding 342 mg salvianolic acid B at 98% purity from 500 mg of the crude extract in a one-step separation.

Benzofurans↗
PubMed2002

Preparative separation of lappaconitine, ranaconitine, N-deacetyllappaconitine and N-deacetylranaconitine from crude alkaloids of sample Aconitum sinomontanum Nakai by high-speed counter-current chromatography.

Analytical high-speed counter-current chromatography (HSCCC) was used for the systematic selection and optimization of the two-phase solvent system to separate alkaloids from Aconitum sinomontanum Nakai. The optimum solvent systems CHCl3-MeOH-0.3 M/0.2 M HCl (4:1.5:2, v/v) thus obtained led to the successful separation of lappaconitine, ranaconitine, N-deacetyllappaconitine and N-deacetylranaconitine from 60 to 500 mg of crude alkaloid sample by preparative HSCCC separation.

Aconitine↗
PubMed2002

Isolation of the lignan secoisolariciresinol diglucoside from flaxseed (Linum usitatissimum L.) by high-speed counter-current chromatography.

High-speed counter-current chromatography was successfully used for the isolation and purification of secoisolariciresinol diglucoside, a bioactive lignan from flaxseed (Linum usitatissimum L.). The solvent system consisted of tert.-butylmethyl ether-n-butanol-acetonitrile-water (1:3:1:5). The purity and identity of the isolated compound was checked by high-performance liquid chromatography analysis in combination with mass spectrometry and NMR measurements.

Butylene Glycols↗
PubMed2002

Separation of tanshinones from Salvia miltiorrhiza bunge by multidimensional counter-current chromatography.

Analytical and preparative high-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of tanshinones from the roots of Salvia miltiorrhiza Bunge. Using multidimensional HSCCC, four major components including tanshinone IIA (16 mg), tanshinone I (10 mg), dihydrotanshinone I (7 mg) and cryptotanshinone (11 mg) were isolated each at high purity of over 95%.

Abietanes↗
PubMed2002

Purification of Food Color Red No. 106 (acid red) using pH-zone-refining counter-current chromatography.

pH-Zone-refining counter-current chromatography was successfully applied to the separation of the main components of Food Color Red No. 106 (R-106, acid red, Color Index No. 45100). A 300-mg quantity of sample was separated using the following two-phase solvent system: n-butanol-water, 40 mM sulfuric acid in organic stationary phase and 30 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by high-performance liquid chromatography and fast atom bombardment mass spectrometry. The separation yielded 261.9 mg of main component of acid red with purity of 99.9%.

Chromatography, High Pressure Liquid↗