Application of High-Speed Counter-Current Chromatography Preparative Separation of Flavone C-Glycosides From Lophatherum gracile

Preparative high-speed counter-current chromatography (HSCCC) was used to separate and purify bioactive constituents from the stems and leaves of Lophatherum gracile Brongn. Six flavone C-glycosides each at over 95% purity including two new compounds were obtained in one-step separation by HSCCC with an optimized two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water at volume ratio of 4:2:1.5:8.5 (v/v/v/v). The experiment yielded 19.9 mg of luteolin 6-C-β-D-galactopyranosiduronic acid (1→2)-β-D-glucopyranoside (1), 28.5 mg of luteolin 6-C-α-L-arabinopyranosyl-7-O-β-D-glucopyranoside (2), 31.5 mg of isoorientin (3), 44.8 mg of orientin (4), 25.3 mg of swertiajaponin (5) and 12.1 mg of apigenin 6-C-β-D-galactopyranosiduronic acid (1→2)-β-D-glucopyranoside (6) from 500 mg of crude extracts. The purity of these compounds was determined by high-performance liquid chromatography (HPLC). Their chemical structures were identified by electron spray ionization mass spectroscopy (ESI-MS), ¹H and ¹³C nuclear magnetic resonance spectroscopy (NMR).     

Isolation and Purification of Two Constitutes from Dendrobium fimbriatum Hook by High-Speed Counter-current Chromatography Using Stepwise Elution

Abstract

Preparative high-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of 2-hydroxyethyl caffeate and denhydroshizukanolide from Dendrobium fimbriatum Hook using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v) and (3:1:3:1, v/v). Using a preparative unit of the HSCCC centrifuge, about a 100 mg amount of the sample was separated, yielding 13.3 mg of 2-hydroxyethyl caffeate and 18.0 mg of denhydroshizukanolide at a high purity of over 95%. The peak fraction of HSCCC was identified by ¹H NMR and ¹³C NMR.     

Separation and Purification of Arctiin,Arctigenin, Matairesinol,and Lappaol F from Fructus Arctii by High-Speed Counter-Current Chromatography

Arctiin (I), arctigenin (II), matairesinol (III), and lappaol F (IV) were isolated and purified from the traditional Chinese medicine Fructus Arctii by high-speed counter-current chromatography (HSCCC). The crude extracts from Fructus Arctii were treated with D101 macroporous resin first and divided into two parts: fraction 1 and fraction 2. Fraction 1 was separated by ethyl acetate-n-butanol-water (4:0.5:5, v/v/v) and yielded 164 mg of I from 250 mg of fraction 1. Fraction 2 was separated by n-hexane-ethyl acetate-methanol-water (2:3:2:3, v/v/v/v) and yielded 27 mg of II, 5 mg of III, and 3 mg of IV from 150 mg of fraction 2. The purities of the four compounds were 99.64%, 98.48%, 96.16%, and 91.41%, respectively, as determined by HPLC-DAD. The chemical structures of the isolated compounds were identified by MS, UV, ¹H NMR, and ¹³C NMR analysis.     

Preparative Isolation of Bioenhancer Loganetin from sf Alstonia scholaris by Fast Centrifugal Partition Chromatography

Fast centrifugal partition chromatography (FCPC) was successfully applied in the separation of close R f complex bioactive iridoid, loganetin directly from the ethyl acetate extract of Alstonia scholaris . The experiment was performed with a two-phase solvent system composed of methyl tert- butyl ether (MtBE)/ACN/Water (3:1.5:3 v/v/v) where the lower phase of the biphasic system, the aqueous layer containing 8 mM HCl, was the stationary phase, while the upper organic layer supplemented with 15 mM triethylamine TEA was designated as the mobile phase. From 1.5 g of EtOAc extract, 48 mg of loganetin (1) was obtained in 94.4% purity as determined by HPLC. The isolated compound (1) was characterized on the basis of its ¹ H, ¹³ C–NMR, and ESI-MS spectroscopic data. Although loganetin does not possess antibacterial activity of its own, but in combination, it appreciably reduces the minimum inhibitory concentration (MIC) of nalidixic acid (NA) against nalidixic acid resistant (NAREC) and nalidixic acid sensitive (NASEC) strains of Escherichia coli . Loganetin, a very common, inexpensive, and non-toxic natural product may finds its application in the antibacterial drug development for treating multidrug-resistant Gram negative infections.     

Enrichment and Separation of Sinomenine and Acutumine from Sinomenium acutum by pH-Zone-Refining Counter-Current Chromatography

Enrichment and separation of alkaloids from a chloroform extract of Sinomenium acutum has been successfully performed for the first time using pH-zone-refining counter-current chromatography. The two-phase solvent system used for enrichment was composed of Methyl tert-butyl ether (MtBE)–acetonitrile (CH₃CN)–water (4:1:5, v/v), where 10 mM triethylamine (TEA) was added to the upper organic stationary phase as a retainer and 10 mM hydrochloric acid (HCl) to the aqueous mobile phase as an eluter, which could enrich the alkaloids from the crude extract well. For the preparative separation, the solvent system consisted of MtBE–CH₃CN–water (4:0.5:5, v/v) with 10 mM TEA in organic stationary phase and 5 mM HCl in the aqueous mobile phase, which could separate and purify the enriched crude alkaloids successfully. 0.82 g of crude alkaloids was enriched from 1.60 g of chloroform extract in the first step separation. From the enriched crude alkaloids, 376 mg of sinomenine and 85 mg of acutumine were obtained in the second step separation with the purity of 98.1% and 98.7%, respectively. The chemical structures of the isolated compounds were identified by UV, ESI-MS and ¹H NMR.     

One Step Large-Scale Separation and Purification of Rutin from Boenninghausenia sessilicarpa by Countercurrent Chromatography

In this study, a preparative countercurrent chromatography (CCC) method for isolation and purification of the bioactive component rutin directly from the ethanol extract of Boenninghausenia sessilicarpa was successfully established by using n-butanol-ethyl acetate-water as the two-phase solvent system. The upper phase of n-butanol-ethyl acetate-water (4:1:5, v/v) was used as the stationary phase of CCC. Under the optimum conditions, 112 mg of rutin at 98.6% purity was obtained from 2.0 g of the crude extract in a single CCC separation. The peak fraction of CCC was identified by negative ESI, ¹H NMR, and ¹³C NMR.     

One Step Purification of Piperine Directly from Piper nigrum L. by High Performance Centrifugal Partition Chromatography

Abstract

In this study, a preparative high performance centrifugal partition chromatography (HPCPC) method for isolation and purification of the bioactive component piperine directly from the ethanol extract of Piper nigrum L. was successfully established by using n-hexane-ethyl acetate-methanol-water as the two-phase solvent system. The upper phase of n-hexane-ethyl acetate-methanol-water (6:5:6:5, v/v) was used as the stationary phase of CPC. Under the optimum conditions, 40 mg of piperine at 98.5% purity, as determined by HPLC, was yielded from 300 mg of the crude extract in a single CPC separation. The peak fraction of CPC was identified by ¹H NMR and ¹³C NMR.     

Separation and Purification of Bioactive Flavonol Glycosides from Hedyotis diffusa Willd by High-Speed Counter-Current Chromatography

Three flavonoid glycosides including quercetin-3-O-[2″-O-(6″′-O-E-sinapoyl)-β-D-glucopyranosyl]-β-D-glucopyranoside(I), quercetin-3-O-[2″-O-(6″′-O-E-feruloyl)-β-D-glucopyranosyl]-β-D-glucopyranoside(II) and quercetin-3-O-[2″-O-(6″′-O-E-feruloyl)-β-D-glucopyranosyl]-β-D-galactopyranoside(III) were isolated and purified from Hedyotis diffusa Willd by high-speed counter-current chromatography (HSCCC). This run was carried out with a two-phase solvent system composed of n-hexane–ethyl acetate–n-butanol–methanol–1.0% acetic acid (1:1:3.5:1:4.5, v/v) by eluting the lower phase as the mobile phase with a flow-rate at 2.0 ml/min. Consequently, 29.6 mg of I, 35.1 mg of II, 41.3 mg of III with purities of over 95% were obtained from 200 mg of the crude extracts in a single run in less than 130 min. The structure of the isolated compounds was confirmed by MS, ¹H NMR, and ¹³C NMR analysis.     

Separation and Purification of Two Isomeric Saponins from Albiziae Cortex by High-Speed Counter-Current Chromatography and Preparative High-Performance Liquid Chromatography

Following constituents’ enrichment steps with the AB-8 macroporous resin, silica gel, and ODS columns, high-speed counter-current chromatography (HSCCC) and preparative HPLC were successfully used for the isolation and purification of two complex isomeric saponins including a new one from albiziae cortex. The two-phase solvent system used for separation was composed of n -hexane/ n -butanol/water (1:10:5, v/v/v ). A total of 8.2 mg julibroside J _{5 a} and 11.6 mg julibroside J ₅ with purity of higher than 98%, respectively, as determined by HPLC-ELSD were obtained from the constituents enriched fraction (475.4 mg) of albiziae cortex. Their structures were identified by HR-MS, ¹ H NMR ¹³ C NMR, and 2D NMR. This is the first ever report on the separation of complex isomeric saponins from albiziae cortex by HSCCC.     

Isolation and Purification of Kaempferol-3,7-O-α-L-Dirhamnopyranoside from Siraitia grosvenori Leaves by High-Speed Counter-Current Chromatograph and Its Free Radical Scavenging Activity

Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of flavonoid glycoside from the leaves of Siraitia grosvenori by using a two-phase-solvent system composed of ethyl acetate–n-butanol–water (4:1:5, v/v/v). kaempferol-3,7-O-α-L-dirhamnopyranoside was obtained in one-step separation and less than 5.5 h from 90 mg of crude extract from the S. grosvenori leaves. The chemical structure of this compound was identified by MS, ¹H NMR, and ¹³C NMR. Free radical scavenging activity of kaempferol-3,7-O-α-L-dirhamnopyranoside was also evaluated and the results showed that it had good free radical scavenging activity with its IC₅₀ value being 3.97 mg/ml.     

Solvent extraction and separation of rare earths from chloride media using α-aminophosphonic acid extractant HEHAMP

Solvent extraction and separation of rare earths (REs: La ~ Lu, plus Y and Sc) by a novel synthesized extractant, (2-ethylhexylamino)methyl phosphonic acid mono-2-ethylhexyl ester (HEHAMP, abbreviated as H₂A₂), were investigated in chloride medium. The favorable separation factors (SFs) between adjacent heavy REs suggested that HEHAMP has a better separation performance than P507. The extracted complex of trivalent REs was determined to be REClH₂A₄ by the slope analysis method. Thermodynamic parameters (ΔH, ΔG, and ΔS) of Lu were calculated as 7.47 kJ mol^?1, ?6.05 kJ mol^?1, and 45.4 J mol^?1 K^?1 at 298.15 K, respectively, which indicate that the extraction reaction of Lu is an endothermic process. The loading capacity of 30% (v/v) HEHAMP toward Lu(III), Yb(III), and Y(III) was about 15.17 g Lu₂O₃/L, 14.46 g Yb₂O₃/L, and 12.64 g Y₂O₃/L, respectively. HCl is the most efficient stripping acid, and 92% of the loaded Yb(III) can be stripped by one-stage stripping with 2 mol/L HCl.     

Separation and Purification of Three High-Purity Isoflavonoids from Belamcanda chinensis (L.) DC. by Supercritical Fluid Extraction and High-Speed Counter-Current Chromatography

Supercritical fluid extraction (SFE) was used to extract three isoflavonoids including irigenin, irisfloretin and dichtomitin from Belamcanda chinensis (L.) DC. The parameters including pressure, temperature, sample particle size, and flow rate of CO₂ were optimized with an orthogonal test. Under the optimized conditions of 15 MPa, 55°C, a sample particle size of 20–40 mesh and CO₂ flow rate of 40 L h^?1. The process was then scaled up by 10 times using a preparative SFE system. The yield of the crude extract from SFE was 4.1%, which contained irigenin, irisfloretin, and dichtomitin 0.71%, 0.49%, and 0.05%, respectively. To compare the extraction methods, Soxhlet Extraction (SE) was performed. The results indicated that SFE was better than SE. Irigenin, irisfloretin, and dichtomitin in the SFE extract were then separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (2:4:3:3, v/v). From 5.0 g of dry crude extract, 27.8 mg irigenin, 16.4 mg irisfloretin, and 2.1 mg dichtomitin were obtained at purities of 97.1%, 96.4%, and 98.0%, respectively, as determined by HPLC-PDA. These results well indicate that SFE and HSCCC are very powerful techniques for the extraction and purification of irigenin, irisfloretin, and dichtomitin from B. chinensis.     

Preparative Isolation of Bioactive Nitrile Glycoside “Niazirin” from the Fruits of Moringa oleifera Using Fast Centrifugal Partition Chromatography

Fast centrifugal partition chromatography was successfully applied in the separation of bioactive constituent niazirin directly from the chloroform extract of Moringa oleifera. The experiment was performed with a two-phase solvent system composed of ethyl acetate/BuOH/water (6:0.5:4 v/v/v) in which the upper organic layer was used as stationary phase and lower aqueous phase was used as mobile phase. From 1 g of crude extract, 70 mg of niazirin was obtained in 94.8% purity as determined by HPLC. The total yield recovery was >94%. The isolated nitrile glycoside (niazirin) was characterized on the basis of its ¹H, ¹³C-NMR and ESI-MS data.     

Equilibria,Kinetics, and Modeling of Extraction of Citric Acid from Aqueous Solutions with Alamine 336 in 1-Octanol

Experimental equilibrium and kinetic data on the extraction of citric acid from aqueous solutions using Alamine 336 in 1-octanol have been determined. The distribution coefficient has increased from 0.029 to 71.727 with increase of Alamine 336 concentration from 0 to 30% (v/v). The chemical equilibria was interpreted as a result of consecutive formation of acid-amine species with 1:1 stoichiometry and the equilibrium complexation constant, K _E1 , has been estimated as 20.186 m³ kmol^?1. The mass-transfer coefficients of citric acid, Alamine 336, and 1:1 acid-alamine complex in 1-octanol were calculated from acetic acid mass-transfer coefficient, which was determined by measuring its fluxes of simple diffusion from kerosene to water. Based on the Hatta number and the criterion given by Doraiswamy and Sharma, the reaction regime has been found to be instantaneous reaction regime occurring at the interface on the organic phase side. An extraction model comprising 1:1 equilibrium complextion constant, K _E1 , and complex mass-transfer coefficient, k _BA (3.79 × 10^?6 m s^?1), has been developed, and it explained the present system satisfactorily.     

离子液体中结晶分离熊果酸和齐墩果酸研究

为拓展结晶溶剂的范围和提高结晶分离熊果酸和齐墩果酸的性能，引入离子液体作为结晶溶剂。测定了熊果酸和齐墩果酸在六种离子液体+乙醇溶液中的溶解度数据，根据该数据，选取1-辛基-3-甲基咪唑六氟磷酸+乙醇混合溶液作为溶剂对熊果酸和齐墩果酸进行了结晶分离，并采用单因素实验对结晶工艺进行了初步优化。结果表明：在1-辛基-3-甲基咪唑六氟磷酸质量分数5%，熊果酸和齐墩果酸质量比1.5∶1，结晶温度30℃，结晶时间14 h的条件下，结晶产物中齐墩果酸的质量分数可以达到85%左右。     

Separation and Purification of Quinolone Alkaloids from the Chinese Herbal Medicine Evodia rutaecarpa (Juss.) Benth by High Performance Counter-Current Chromatography

Preparative separation of quinolone alkaloids in Evodia rutaecarpa (Juss.) Benth was conducted by high performance counter-current chromatography (HPCCC) with a pair of two solvent systems consisting of n-hexane-methanol-water-acetic acid (2:1:1:0.2, v/v) and (5:4:2:0.1, v/v). Consequently, 31.78 mg 1-methyl-2-nonyl-4 (1H)-quinolone (I), 59.25 mg 1-methyl-2-(6-undecenyl)-4 (1H)-quinolone (II), 333.27 mg evocarpine (III), 101.13 mg 1-methyl-2-(6,9-pentadecadienyl)-4(1H)-quinolone (IV), 132.17 mg dihydroevocarpine (V), and 86.99 mg 1-methyl-2-(10-pentadecenyl)-4(1H)-quinolone (VI) were obtained from 1.3 g of the crude extract. The structures of these compounds were identified by mass spectrometer (MS), nuclear magnetic resonance (¹H NMR and ¹³C NMR).     

Ultrasonic assisted extraction of ursolic acid from apple pomace: A novel and facile technique

Substantial amount of apple pomace (AP) is produced in apple processing industries and is often discarded as waste which becomes a source of polluting the environment. However, the by-product constitutes a promising bioresource of ursolic acid with various biological activities. Therefore, this particular research study was aimed to develop a novel and facile method to separate ursolic acid from AP. First, AP was extracted with ultrasound assistance using methanol as extraction solvent, 2.86% with 10:1 (mL g^?1) of liquid–solid ratio, 300 W of ultrasonic power, 50°C of extraction temperature, and 90 min of ultrasonic time. Meanwhile, the disruption effect of ultrasound on AP was observed by scanning electron microscope. Second, a novel and facile method was applied to separation of ursolic acid, then a perfect colorless needle crystal of ursolic acid was obtained with the yield of about 1.34% of dry AP.     

Effective and Preparative Separation of Bioactive Flavonoids From Gynostemma Pentaphyllum Tea Using Elution-Extrusion Counter-Current Chromatography

Elution-extrusion counter-current chromatography (EECCC) was successfully applied for screen and separation of four flavonoids from Gynostemma pentaphyllum tea, a popular herbal tea extract in China. With the hexane/ethyl acetate/methanol/water 5/6/5/6 (v/v) system, 300 mg of G. pentaphyllum tea extract were fractionated on a 180 mL-capacity preparative hydrodynamic CCC column. Satisfactory separation efficiency was achieved, producing milligram-amounts of quercetin, isorhamnetin, and cirsiliol over 90% pure in one EECCC process. Due to the hydrophilic property, the major flavonoid glycoside, rutin, was co-eluted with the solvent front as a mixture. Therefore, another carefully selected biphasic liquid system composed of ethyl acetate/n-butanol/water (4/1/5, v/v) was employed, yielding 35 mg of rutin with 97.1% purity. Structures of all separated compounds were identified by ESI-MS, ¹H NMR, and ¹³C NMR.     

Preparative Separation and Purification of Three Flavonoids from the Anti-Inflammatory Effective Fraction of Smilax china L. by High-Speed Counter-Current Chromatography

Flavonoids are the main chemical constituents of Smilax china L. and thought to be responsible for the anti-inflammatory activity of Smilax china L. In this study, a suitable HSCCC method was developed to separate the three main flavonoids in a one-separation from the anti-chronic pelvic inflammation disease (CPID) effective fraction of Smilax china L. with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:10:1:10, v/v/v/v). 42 milligrams of astilbin, 10 mg neoisoastilbin, and 6 mg quercetin-3-O-α-L-rhamnoside were separated from 200 mg of the anti-CPID effective fraction of Smilax china L. with purity of 98.3%, 98.7%, 98.5%, respectively, by HPLC analysis. Orthogonal test L₉ (3⁴) was also applied to investigate the optimum extracting conditions of the three flavonoids. HSCCC was successfully used for the isolation and purification of the three flavonoids from the anti-CPID effective fraction of Smilax china L. and the neoisoastilbin was first separated from Smilax china L.     

Application and Comparison of High-Speed Countercurrent Chromatography and High Performance Liquid Chromatography in Preparative Enantioseparation of α-Substitution Mandelic Acids

This paper is mainly about extending research on application and comparison of preparative high-speed countercurrent chromatography (HSCCC) and preparative high performance liquid chromatography (HPLC) in chiral separations. Preparative enantioseparations of α-cyclopentylmandelic acid and α-methylmandelic acid by HSCCC and HPLC were compared using hydroxypropy-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as the chiral mobile phase additives. In preparative HPLC the enantioseparation was achieved on the ODS C₁₈ reverse phase column with the mobile phase composed of a mixture of acetonitrile and 0.10 mol L^?1 phosphate buffer at pH 2.68 containing 20 mmol L^?1 HP-β-CD for α-cyclopentylmandelic acid and 20 mmol L^?1 SBE-β-CD for α-methylmandelic acid. The maximum sample size for α-cyclopentylmandelic acid and α-methylmandelic acid was only about 10 mg and 5 mg, respectively. In preparative HSCCC the enantioseparations of these two racemates were performed with the two-phase solvent system composed of n-hexane-methyl tert.-butyl ether-0.1 molL^?1 phosphate buffer solution at pH 2.67 containing 0.1 mol L^?1 HP-β-CD for α-cyclopentylmandelic acid (8.5:1.5:10, v/v/v) and 0.1 mol L^?1 SBE-β-CD for α-methylmandelic acid (3:7:10, v/v/v). Under the optimum separation conditions, totally 250 mg of racemic α-cyclopentylmandelic acid could be completely enantioseparated by HSCCC with HP-β-CD as a chiral mobile phase additive in a single run, yielding 114-116 mg of enantiomers with 98-99% purity and 89-92% recovery. But, no complete enantioseparation of α-methylmandelic acid was achieved by preparative HSCCC with either of the chiral selectors due to their limited enantioselectivity. In this paper, preparative enantioseparation by HSCCC and HPLC was compared from various aspects.