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Forsythoside A and suspensaside A were isolated and purified fromForsythia suspensaby one step of high-speed counter-current chromatography for the first time using a solvent system of ethyl acetate-n-butanol-methanol-water (4:0.5:0.5:5,v/v). The purities of the two compounds were 98.19% and 98.05%, respectively, as determined by HPLC. Their structures were identified by MS, UV, and NMR analysis. Such a simple and effective method was fairly useful to prepare pure compounds as reference substances for related study onForsythia suspensa. [ABSTRACT FROM PUBLISHER]

An effective high–speed counter–current chromatography (HSCCC) method was established for semi-preparative isolation and purification of bioactive chemical constituents from the Tibetan medicinal plantPedicularis longifloravar.tubiformis(Klotzsch) P. C. Tsoong. With a two-phase solvent system composed of chloroform–methanol–water (8:4:5, v/v), 40 mg of extract was separated to yield luteolin (12.5 mg), apigenin (9.6 mg), and chrysoeriol (4.8 mg), with purities of 99.3, 98.2, and 98.6%, respectively, as determined by high-performance liquid chromatography (HPLC). The chemical structures of these three components were identified by1H NMR and13C NMR. [ABSTRACT FROM PUBLISHER]

The detrimental effect of heterogeneity on the efficiency of particle packed columns has been a long standing issue in chromatographic separations. This heterogeneity arises from the difference in packing density between the wall and central regions of the chromatographic bed and imparts radial variance in mobile phase velocity through the column. In conjunction with the uneven distribution of the sample band through frits and distributors at the head of the column, the resultant effect is a decrease in efficiency due to the formation of a parabolic-“like” sample band. We introduce the concept of “Active Flow Management” to counteract the effects of column heterogeneity via the separation of the flow eluting from the center of the column from that of the flow eluting near the peripheral wall region. The flow streams from the two aforementioned regions are separated by the use of a specialized column outlet fitting. By varying the ratio of flow eluting from the center to the peripheral region it was possible to increase the efficiency of a 100 × 21 mm column by up to 57% compared to a column operated in the conventional manner. [ABSTRACT FROM AUTHOR]

A successful method of preparative high-speed counter-current chromatography (HSCCC) was established for direct isolation and purification of hydrolysis products ofEpimedium koreanumNakai to obtain the secondary glycosides and aglycons of flavonoids inE. koreanum. The two-phase solvent systems of HSCCC composed n-hexane-ethyl acetate-methanol-water at the ratios of 6:3.5:6:5 (v/v) and 6:3.5:8:5 (v/v) were used in a stepwise elution. Totally, 60.1 mg of FractionIthat would be isolated and purified by preparative HPLC, 9.4 mg of icartin (4), 3.5 mg of desmethylicartin (5), 4.7 mg of 3′′-ethyoxyl-icartin (6), 7.3 mg of anhydroicaritin (7), and 10.1 mg of β-anhydroicaritin (8) were obtained in one-step separation from 100 mg of the crude materials with purities of 97.7%, 96.2%, 99.2%, 99.5%, and 91.0%, respectively. And FractionIof HSCCC was purified by the preparative HPLC to obtain 12.7 mg of pletypetaloside (I-1), 6.8 mg of icariside I (I-2) and 16.3 mg of 3′′-ethyoxyl-pletypetaloside (I-3) with purities of 90.8%, 93.4%, and 99.2%. All of the chemical structures were identified on the basis of widely spectral technology including 2D-NMR. Among them, compoundsI-3and6are novel. [ABSTRACT FROM AUTHOR]

Prenylated isoflavonoids such as 6,8-diprenylorobol, 6,8-diprenylgenistein and 4′-O-methylalpinumisoflavone were purified from n-hexane extract of C. tricuspidata fruits using centrifugal partition chromatography (CPC) with a n-hexane-ethyl acetate-methanol-water (7:3:6:4, v/v, ascending mode) solvent system in a one-step within 200 min. One-step preparative CPC yielded 22.4 mg of 6,8-diprenylorobol and 26.7 mg of 6,8-diprenylgenistein with 95% and 85% purity, respectively, from 350 mg of crude hexane extract. Further purification by crystallization in methanol yielded 4′-O-methylalpinumisoflavone (9.3 mg) at over 95% purity based on the HPLC analysis. The chemical structures of purified compounds were elucidated by 1H, 13C NMR, and ESI-MS. [ABSTRACT FROM AUTHOR]

Centrifugal partition chromatography (CPC) is a type of counter current separation technique and was first invented by Sanki Eng. Ltd. in Kyoto. Since the year of 1982, CPC has been used to isolate or fractionate bioactive materials and has shown its efficiency in the purification process of natural products from plants and microorganisms. This review focuses on the CPC applications for the purification of over 250 compounds from 60 plant materials and microorganisms between 1994 to September 2009. [ABSTRACT FROM AUTHOR]

α-diketones are important precursors for the synthesis of a wide variety of compounds. Many methods for the synthesis of 1,2-diketones using a variety of reagents have been reported. Almost all the methods result in the formation of by-products in small or major amounts. In this paper, the development of a column chromatographic method for the separation of a diketone from keto-ester is reported. The column conditions standardized for the purification of the diketone from keto-ester may also find application in similar cases involving the presence of more polar by-products formed along with the diketone during the course of the reaction. [ABSTRACT FROM AUTHOR]

Black currant is an important material in the food industry, but little research has been reported on the isolation of phenolic acids because of their low content. In the present study, high-speed countercurrent chromatography (HSCCC) has been successfully used for the preparative isolation of the minor phenolic compounds from the ethyl acetate extracts of black currant fruit. The HSCCC separation was performed with a two phase solvent system composed of n-hexane/EtOAc/MeOH/H2O (5:15:4:7 v/v) at a flow rate of 1.5 mL/min. From a 500 mg crude sample 0.8 mg of protocatechuic acid, 1.0 mg of caffeic acid, 0.5 mg of 4-hydroxybenzoic acid, and 2.5 mg of myricetin were purified by a one step HSCCC operation,. Their chemical structures were confirmed by MS and NMR. [ABSTRACT FROM AUTHOR]

The application of high speed countercurrent chromatography to the preparative purification of crude single walled carbon nanotubes is described. The purification was accomplished on the basis of an experiment that dispersed the single walled carbon nanotubes with aniline, the result mixture was separated by high speed countercurrent chromatography using the two phase system composed of chloroform/methanol/water = 4/4/2. The sizes of SWNTs separated were observed by scanning electron microscopy. The experimental results demonstrated that the high speed countercurrent chromatography possessed good efficiency for purification of single walled carbon nanotubes. [ABSTRACT FROM AUTHOR]

Significant amounts of vitamin B 12 (about 116.3∼⃒556.3 µg/100 g) were determined in a Japanese salted and fermented salmon kidney “Mefun.” A corrinoid compound was purified to homogeneity from Mefun and partially characterized. TLC and HPLC patterns of the purified corrinoid compound were identical to those of authentic vitamin B 12 , but not to inactive corrinoids. The vitamin B 12 found in Mefun was not derived from concomitant vitamin B 12 ‐synthesizing bacteria, but had accumulated in the salmon kidney. Gel filtration experiments demonstrated that most of the vitamin B 12 found in Mefun was recovered in the free vitamin B 12 fractions. These results indicate that Mefun would be an excellent vitamin B 12 (free form) source for elderly persons with food‐bound vitamin B 12 malabsorption. [ABSTRACT FROM AUTHOR]

Ion‐Exchange centrifugal partition chromatography using benzalkonium chloride as a strong exchanger (SIXCPC) was successfully used to purify rosmarinic acid from a crude extract that was produced by callus culture. The purification process was carried out on a gram scale using the ternary biphasic system CHCl 3 : n ‐BuOH∶water 4.5:1:4.5 v/v/v in the ascending mode (mobile aqueous phase and stationary organic phase). Two particular points are discussed: the influence of benzalkonium chloride on ternary solvent system stability and the advantage of injecting the analytes as sodium salts rather than molecular acids. [ABSTRACT FROM AUTHOR]

A facile, preparative low-pressure chromatographic process was developed for purification of paclitaxel from crude extract of Taxus spp. The process consisted of normal-phase and a reversed-phase chromatography without utilization of any liquid-liquid partition step. The normal phase chromatography was designed lo separate paclitaxel from a majority of unwanted compounds to obtain an initial purification. Silica gel and Al2O3, were compared as packing materials for this step. The result demonstrated that basic Al2O3 was better than silica gel to give a higher throughput. A further advantage of the Al2O3 was its ability of removing l0-deacetyl-7-epipaclitaxel. a compound difficult to be separated from the paclitaxel in subsequent purification. The chromatographic fraction of A2O3 was purified by a subsequent reversed-phase column chromatography, employing a novel uniform porous microsphere, named PST, as the packing material. Combination of the two steps of column chromatography and one step of crystallization was able to purify paclitaxel, from 0.46% to more than 98% with the total recovery- of 71%. This integrated chromatographic procedure was reproducible, efficient, and simple to use. [ABSTRACT FROM AUTHOR]

Epigallocatechin (EGC) was prepared by the degallation of Epigallocatechin-O-3-gallate (EGCG). EGCG was completely converted to EGC and gallic acid by adding 4 mg tannase/100 mg EGCG at the concentration of 2 mg/mL under pH 6.0, at 35°C for 30 min. EGC was then separated from the reaction mixture by HSCCC, using a two-phase solvent system composed of hexane–ethyl acetate–water (1/9/10, v/v/v). Finally, 1.3 g of EGC at 97% purity was prepared from about 2.3 g of EGCG at 85% purity, indicating that EGC was almost completely recovered by HSCCC. [ABSTRACT FROM AUTHOR]

Preparative scale purification of PEG-protein conjugates by centrifugal precipitation chromatography is discussed. By utilizing the transport of ammonium sulfate across a membrane and the centrifugal force, an ammonium sulfate gradient is formed and used for differential precipitation of PEG-protein conjugates. Native proteins can be separated from PEG-protein conjugates by using this technique. [ABSTRACT FROM AUTHOR]

Centrifugal partition chromatography linked with evaporative light scattering detection has been investigated to achieve the large scale-up isolation of oraposide which is a phenylpropanoid glycoside having a radical-scavenging activity. A two-phase solvent system has been studied to improve the yield of pure product and to decrease the cost of purification. A comparison with preparative HPLC has been made. [ABSTRACT FROM AUTHOR]