Separation and Purification of α-Cyperone from Cyperus rotundus with Supercritical Fluid Extraction and High-Speed Counter-Current Chromatography

Abstract

α-Cyperone was separated and purified for the first time from essential oil of the traditional Chinese medicinal plant Cyperus rotundus L. by high-speed counter-current chromatography (HSCCC). Essential oil was obtained by extraction with supercritical carbon dioxide under the pressure of 20 MPa and temperature of 40°C. The separation was performed in one step with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.2:1.1:0.2, v/v), in which the lower phase was used as the mobile phase at a flow-rate of 2.0 ml/min in the head-to-tail elution mode. A total of 60 mg α-cyperone at 98.8% purity was yielded from 0.9 g essential oil as determined by HPLC analysis. The structure of the target compound was performed by electron impact ionization mass spectrometry (EI-MS) and further conformed by comparison with an authentic sample (National Institute of the Control of Pharmaceutical and Biological Products, Beijing, China).     

Direct Selective Extraction of Trivalent Americium from PUREX Raffinate Using a Combination of CyMe4BTPhen and TEDGA—A Feasibility Study

The direct and selective extraction of Am(III) from simulated PUREX raffinate is demonstrated using a novel combination of the lipophilic extractant CyMe₄BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[e]-[1,2,4]triazin-3-yl)-1,10-phenanthroline) and the hydrophilic complexant TEDGA (N,N,N’,N’-tetraethyl-diglycolamide) to enhance selectivity toward Am(III) extraction. Separation factors (SF) of up to SF_Am/Cm = 4.9 were observed in tracer experiments using this combination of CyMe₄BTPhen and TEDGA. Distribution ratios of stable isotopes of fission and activation products contained in a simulated PUREX raffinate solution are reported for the first time with CyMe₄BTPhen, and some co-extracted metal ions are identified. The metal ions partly co-extracted from the simulated PUREX raffinate solution were Cu, Pd, Cd, Ag, Ni, and to a lesser extent Sn and Mo. The co-extraction of Pd and Ag was successfully suppressed using Bimet ((2S,2’S)-4,4’-(ethane-1,2-diylbis(sulfanediyl))bis(2-aminobutanoic acid)). The extraction was also studied as a function of the TEDGA concentration. The distribution ratios of Am and Cm can be adjusted by variation of the TEDGA concentration to yield D_Am values >1 and D_Cm values <1. Separation factors for Am(III) over Cm(III) of up to SF_Am/Cm = 2.4 were observed in these experiments. For Ln(III) + Y(III), distribution ratios below 1 were observed, thus enabling a direct extraction of Am(III) from simulated PUREX raffinate with a sufficient selectivity against trivalent lanthanides and Cm(III).     

Molecular Modeling Study of Chiral Separation and Recognition Mechanism of β-Adrenergic Antagonists by Capillary Electrophoresis

Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the -OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.     

Separation and Purification of Z Ligustilide and Senkyunolide A from Ligusticum chuanxiong Hort. with Supercritical Fluid Extraction and High‐Speed Counter‐Current Chromatography

Abstract

The essential oil was obtained by supercritical fluid extraction from dried roots of Ligusticum chuanxiong. Different solvent systems for high‐speed counter‐current chromatography (HSCCC) were compared. A system composed of n hexane–ethyl acetate–methanol–water–acetonitrile in the ratio of 8:2:5:5:3 (v/v) was found to be optimum for HSCCC of the essential oil. Z ligustilide and senkyunolide A were separated by HSCCC with purity of 98% determined by GC. The chemical structures of these two components were identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS).     

Kinetic and Thermodynamic Separation of Cu(II) and Fe(III) by Liquid-Liquid Extraction with a β-Hydroxy-oxime in Toluene

Abstract

A quantitative study of the thermodynamic and kinetic separation of Cu(II) and Fe(III) by liquid-liquid extraction with toluene solutions of the oxime 2-hydroxy-5-t-octyl (acetophenone oxime) has been conducted. On the basis of the stoichiometry, equilibrium constants, rate laws and rate constants of the extraction reactions of Cu(II) and Fe(III) an equation has been derived which describes how the separation of Cu from Fe varies with the chemical composition of the system, the hydrodynamics of the extracting apparatus and the contact time between the aqueous and the organic phases. Our results show that separations which are not feasible thermodynamically are possible when the contact time between the two phases is kept much shorter than that required to reach equilibrium.     

Hollow-Fiber Membrane Extraction of Copper from Aqueous Nitrate Media by LIX® Reagents: Comparison of Extraction Efficiency and Fractional Resistances

Abstract

Extraction of copper from nitrate/nitric acid aqueous solutions was studied using a HF Membrane Module and four LIX reagents (LIX® 860N-I, LIX® 984N, LIX® 84-I, and LIX® 65N) containing different active compounds (ketoximes and/or salicylaldoximes). Kinetic experiments varying the flow rates of both phases, aqueous and organic, and the extractant concentration were carried out to compare the extraction rate and efficiency from nitrate-aqueous media. A mathematical model based on the “aqueous extraction mechanism” in which the chemical reaction takes place in an aqueous-reaction zone was applied to determine the individual resistances of the copper mass-transfer process. It was found that the fractional resistance due to chemical reaction in the aqueous reaction zone, which varied from 92.5% to 95.8% in the order LIX® 860N-I < LIX® 984N < LIX® 84-I < LIX® 65N, controlled the total rate of the hollow-fiber copper extraction from nitrate aqueous media.     

Partitioning of α-lactalbumin and β-lactoglobulin from cheese whey in aqueous two-phase systems containing poly (ethylene glycol) and sodium polyacrylate

Partitioning behavior of the whey proteins α-lactalbumin (α-la) and β-lactoglobulin (β-lg) in aqueous two-phase systems prepared with poly ethylene glycol (PEG) and sodium polyacrilate (NaPA) was investigated as a function of pH and polymer concentrations. It was observed that α-la concentrated in the PEG phase while β-lg concentrated in the NaPA phase. Response surface methodology was applied to optimize protein partitioning and to achieve the best conditions for their fractionation. Thermodynamic analysis based on isothermal titration microcalorimetry indicated that the partitioning of α-la was accompanied by endothermic heat and was entropically driven, while β-lg partitioning was accompanied by exothermic heat and was enthalpically driven at low polymer concentrations and entropically driven at high polymer concentrations. Purification and yield parameters were determined using fresh whey and the results allowed for conclusion of the great applicability of this new system for α-la and β-lg fractionation.     

Extraction of cadmium by TODGA–dodecane and TBP–dodecane: A comparative study by MD simulation

Molecular dynamics (MD) simulation of [Cd(II)] along with nitrate ions and water in dodecane was carried out for different nitric acid concentrations. The extraction process using N,N,N’,N’-tetraoctyldiglycolamide (TODGA) and tributyl phosphate (TBP), in biphasic systems, is also simulated at three nitric acid concentrations. In the TBP-based system, the formation of a third phase was observed at 3 M nitric acid concentration. Cd(II) ions form reverse micelles-like clusters with TODGA as an extractant in dodecane. The mass percentage of TODGA in these clusters decreases with increase in the acid concentration while increasing the size of the aggregates at the same time.     

Effect of Stapling Architecture on Physiochemical Properties and Cell Permeability of Stapled α-Helical Peptides: A Comparative Study

Stapled peptides have emerged as a new class of targeting molecules with high binding affinity and specificity for intracellular undruggable targets. Their ability to penetrate cell membranes is exceptionally intriguing but remains elusively and controversially discussed. To understand the effect of stapling architectures on their physiochemical properties and to aid in promoting their cell permeability, we report herein a comparative study on the physiochemical properties and cell permeability of stapled α-helical peptides with different types of crosslinks. We highlight the decisive impact of the intrinsic properties of the crosslinks on cell permeability rather than the helical contents of the peptides in model amphipathic sequences targeting estrogen receptor–coactivator interaction. We envision this finding to shed further light on the chemical optimization of stapled α-helical peptides or macrocyclic cell-penetrating peptides for enhanced cell penetration.     

Mineralization of the Pharmaceutical β-Blocker Atenolol by Means of Indirect Electrochemical Advanced Oxidation Process: Parametric and Kinetic Study

Atenolol is a β-blocker that can be found in urban wastewaters and which is not removed efficiently by conventional wastewater treatments. In the present study, electro-Fenton (EF) process was used to assess the degradation and mineralization of pharmaceutical atenolol in aqueous solutions. Electrolyses of 250 mL of atenolol solution (0.17 mM), at initial pH 3, were carried out in an undivided electrolytic cell in galvanostatic mode. Influence of material cathode (graphite, stainless steel, and platinized titanium), applied current (100–500 mA), sulfate dosage (0.01–0.5 M), and catalyst ferrous ions concentration (1–10 mM), on the oxidation efficiency was studied. Atenolol mineralization was monitored by COD dosage. Kinetic analysis indicated that atenolol mineralization followed a pseudo-first order model and the rate constant increased with rising current, ferrous ions concentration (up to 5 mM) and electrolyte concentration. Results showed that graphite cathode, 0.5 M Na₂SO₄ electrolyte, 0.3 A and 5 mM FeSO₄ catalyst were the best conditions for atenolol mineralization. In these optimal conditions, after 240 min more than 87% of the initial COD was removed. The corresponding current efficiency (CE) and specific energy consumption (SEC) were 22.33% and 0.194 kWh/kg COD, respectively. This latter corresponds to 0.078 kWh/m³ of treated wastewater.     

Cationic Micelles Modulated in the Presence of α,ω-Alkanediols: A SANS,NMR and Conductometric Study

The solution behavior of a typical cationic surfactant, tetradecyltrimethylammonium bromide, in mixed solvent systems composed of water and varying concentrations of α,ω-alkanediols; 1,2-ethanediol (ED), 1,4-butanediol (BD), 1,6-hexanediol (HD) and 1,8-octanediol (OD) was examined via electrical conductance measurements, ¹³C-NMR spectroscopy and small angle neutron scattering (SANS) measurements. The critical micelle concentration (CMC) values and degree of counterion dissociation (α) indicate that both ED and BD oppose micellization, whereas HD and OD enhance micelle formation. Changes in the ¹³C-NMR chemical shifts (∆δ values) reveal that the short chain diols reside almost exclusively in the bulk phase and hence, affect the formation of micelles by altering the solvent properties in the bulk of the solution, whereas HD and OD partition between the pseudomicellar phase and the bulk phase. SANS studies indicated that both the micellar size and aggregation number (N _agg) decrease in the presence of all diols. ED and BD behave like cosolvents and increase the α and CMC values and decrease N _agg. We note that the effect of HD and OD on the properties of the micelles is concentration dependent; at low concentrations, these diols interact with the micelles and behave as cosurfactants (as evidenced by the trends in the micellar properties), while at higher concentrations, they enhance the surfactant solubility and behave as a cosolvent.     

Competitive Binding of Off-Flavor Compounds with Soy Protein and β-Cyclodextrin in a Ternary System: A Model Study

Removal of soy protein (SP)-bound 2-nonanone by β-cyclodextrin (βCD) was studied using an equilibrium dialysis technique. It was observed that in the presence of βCD, a significant (p < 0.05) amount of SP-bound 2-nonanone could be removed in a concentration-dependent manner. Up to 94% of SP-bound 2-nonanone was stripped from SP when 6 mM βCD was present in the system. However, in thermodynamic terms, the net standard free energy change for transfer of 2-nonanone from SP to βCD, i.e., \( \Updelta \Updelta G^\circ_{{{\text{SP}} \to \beta {\text{CD}}}} \), was essentially zero, implying that the apparent equilibrium binding constant for the formation of βCD–2-nonanone complex was essentially same as that for the SP–2-nonanone complex formation in the ternary system. This indicated that stripping-off of 2-nonanone from SP by βCD was driven by the mass action ratio. Based on these results, it is shown that βCD can be used effectively for removing SP-bound off-flavor carbonyl compounds.     

Membrane Binding of Parkinson's Protein α-Synuclein: Effect of Phosphorylation at Positions 87 and 129 by the S to D Mutation Approach

Human α-synuclein, a protein relevant in the brain with so-far unknown function, plays an important role in Parkinson's disease. The phosphorylation state of αS was related to the disease, prompting interest in this process. The presumed physiological function and the disease action of αS involves membrane interaction. Here, we study the effect of phosphorylation at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding. Local binding is detected by spin-label continuous-wave electron paramagnetic resonance. For S87A/D, six positions (27, 56, 63, 69, 76, and 90) are probed; and for S129A/D, three (27, 56, and 69). Binding to large unilamellar vesicles of 100 nm diameter of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in a 1 : 1 composition is not affected by the phosphorylation state of S129. For phosphorylation at S87, local unbinding of αS from the membrane is observed. We speculate that modulating the local membrane affinity by phosphorylation could tune the way αS interacts with different membranes; for example, tuning its membrane fusion activity.     

Characteristics of α′- and β-Sr2SiO4:Eu phosphor powders prepared by spray pyrolysis

α′- and β-Sr₂SiO₄:Eu²⁺ phosphor powders were prepared by spray pyrolysis from the spray solutions with and without NH₄Cl flux. The phosphor powders prepared from the spray solutions with the addition amount of NH₄Cl flux between 2 and 5 wt% of phosphor had regular polyhedron structures and main crystal structure of β-Sr₂SiO₄. On the other hand, the phosphor powders prepared from the spray solution with high addition amount of NH₄Cl flux as 6 wt% of phosphor had irregular morphology and crystal structure of α′-Sr₂SiO₄. The mean size of the β-Sr₂SiO₄ phosphor powders with regular polyhedron structure was 5.2 μm. The β-Sr₂SiO₄:Eu²⁺ phosphor powders had higher photoluminescence intensities than the α′-Sr₂SiO₄:Eu²⁺ phosphor powders. The β-Sr₂SiO₄:Eu²⁺ phosphor powders prepared from the spray solution with 5 wt% NH₄Cl flux of phosphor had the maximum photoluminescence intensity. The wavelengths of the emission spectra showing the maximum peak intensities changed from 543.2 to 561.8 nm when the addition amount of NH₄Cl flux was increased from 2 to 6 wt% of phosphor.     

Recovery of Al,Co, Cu,Fe, Mn,and Ni from spent LIBs after Li selective separation by COOL-Process – Part 2: Solvent Extraction from Sulphate Leaching Solution

The market for lithium-ion batteries (LIB) is experiencing substantial growth, what is owed to electromobility and the growing demand for cordless devices. Securing the raw material base for LIB is mandatory to achieve the objectives of EU commission's Green Deal. This implies not only sufficient access to lithium but also the accompanying metals, above all Co, Ni, Mn. After preceding recovery of Li₂CO₃ by the COOL-Process and subsequent acid digestion of the Li-free black mass, value metals, such as Co, Cu, Ni, and Mn were recovered by counter-current solvent extraction. Fe (98.5 ± 0.65 %), Co/Mn (99.8 ± 0.78 %; 99.9 ± 1.11 %), Al (99.7 ± 1.07 %) and Cu/Ni (97.8 ± 1.46 %; 98.6 ± 1.32 %) were selectively extracted with high discriminatory power using cationic exchangers and solvating extractants such as D2EHPA and TBP, respectively. This way, a complete, holistic recycling process for LIB is at hand that allows for recovering housing material, lithium and the accompanying metals almost quantitatively.     

N,N,N′,N′-Tetra(2-Ethylhexyl) Thiodiglycolamide T(2EH)TDGA: A Promising Ligand for Separation and Recovery of Palladium from High Level Liquid Waste (HLLW) Solutions

The extraction properties of N,N,N′,N′-tetra(2-ethylhexyl)thiodiglycolamide T(2EH)TDGA have been evaluated for the separation and recovery of palladium from simulated high-level liquid waste (SHLW). T(2EH)TDGA has shown very high selectivity for Pd (II) over other metal ions present in SHLW. The separation factor (SF) for Pd (II) over other metal ions was found to be more than 10⁵. Reusability studies of the extractant indicate that D_Pd remained almost constant even after five successive cycles of extraction and stripping. Palladium was quantitatively recovered from thiourea strip solution by treating it with ammonia and filtering the precipitate of palladium sulphide. The acid uptake constant (K_H) was found to be 0.62 which could be due to the presence of two carbonyl groups of amidic moiety. To account for very high extractability of palladium with T(2EH)TDGA over other ‘S’ donor extractants, namely Bis-(2-ethylhexyl)sulphoxide (BESO), FTIR, as well as Raman studies were carried out. FTIR and Raman studies suggested the ligation through carbonyl as well as the thio-ether group. Conditional extraction constants (log K′_ex) were determined and the thermodynamic parameters were calculated from the dependence of the conditional extraction constant (log K′_ex) on temperature. The calculated values of ΔG_ex, ΔH_ex, and ΔS_ex were ?41.78 kJmol^?1, ?55.12 kJmol^?1 and ?44.04 JK^?1 mol^?1 respectively. The extraction process is indicated to be enthalpy driven with the entropy factor counteracting it.     

Problems of spectrophotometry of glass-forming melts: II. A technique for measuring the absorption spectra of glasses and melts in the red and near-infrared ranges at temperatures from 20 to 1500°C

A technique for measuring the absorption spectra of glasses and glass-forming melts in the red visible and near IR ranges, the experimental setup, and the measuring cell intended for use over a wide range of temperatures are described. The main problems concerning the acquisition of reliable data on the absorption spectra of glass-forming melts at high temperatures and the basic sources of errors in measurements of the spectra are considered.     

Solvent Extraction Separation of Niobium(V), Tantalutn(V) or Titanium(IV), and Vanadium(V) by 2′-Hydroxy-4-methoxy-5′-methyl Chalkone Oxime (HMMCO) from Their Binary Mixtures

Abstract

2′-Hydroxy-4-methoxy-5′-methyl chalkone oxime (HMMCO) has been used for the solvent extraction separation of Nb(V), Ta(V) or Ti(lV), and V(V) from their binary mixtures. V(V) can be quantitatively extracted with HMMCO from 9 M hydrochloric acid. The green-colored chloroform extractable V(V)-HMMCO complex absorbs at a maximum at 630 nm. Nb(V), Ta(V), and Ti(IV) are not extracted at these conditions. However, these metals can be extracted from strong hydrochloric acid medium in the presence of potassium thiocya-nate. The yellow-colored complexes of Nb(V), Ta(V), and Ti(IV) absorb at a maximum at 380, 390 and 390 nm, respectively. The method is simple, rapid, and selective, and affords a clean-cut separation of vanadium from niobium, tantalum, or titanium which are usually present in alloys and ores.     

Shikonin Inhibits the Migration and Invasion of Human Glioblastoma Cells by Targeting Phosphorylated β-Catenin and Phosphorylated PI3K/Akt: A Potential Mechanism for the Anti-Glioma Efficacy of a Traditional Chinese Herbal Medicine

Shikonin is an anthraquinone derivative extracted from the root of lithospermum. Shikonin is traditionally used in the treatment of inflammatory and infectious diseases such as hepatitis. Shikonin also inhibits proliferation and induces apoptosis in various tumors. However, the effect of shikonin on gliomas has not been fully elucidated. In the present study, we aimed to investigate the effects of shikonin on the migration and invasion of human glioblastoma cells as well as the underlying mechanisms. U87 and U251 human glioblastoma cells were treated with shikonin at 2.5, 5, and 7.5 μmol/L and cell viability, migration and invasiveness were assessed with CCK8, scratch wound healing, in vitro Transwell migration, and invasion assays. The expression and activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) and the expression of phosphorylated β-catenin (p-β-catenin) and phosphorylated PI3K/Akt were also checked. Results showed that shikonin significantly inhibited the cell proliferation, migration, invasion, and expression of MMP-2 and MMP-9 in U87 and U251 cells. The expression of p-β-catenin showed contrary trends in two cell lines. It was significantly inhibited in U87 cells and promoted in U251 cells. Results in this work indicated that shikonin displayed an inhibitory effect on the migration and invasion of glioma cells by inhibiting the expression and activity of MMP-2 and -9. In addition, shikonin also inhibited the expression of p-PI3K and p-Akt to attenuate cell migration and invasion and MMP-2 and MMP-9 expression in both cell lines, which could be reversed by the PI3K/Akt pathway agonist, insulin-like growth factor-1 (IGF-1).