HPLC comparison of supercritical fluid extraction and solvent extraction of coumarins from the peel of Citrus maxima fruit

The efficiency of carbon dioxide supercritical fluid extraction (SFE) of the biologically active compounds imperatorin, meranzin and meranzin hydrate from the fruit peel of Citrus maxima Merr. has been compared with that of solvent extraction with acetone. Under the best SFE conditions tested for the three coumarins, which involved extraction at 50 degrees C and 27.6 MPa, the extractive efficiencies were 84, 76 and 18% for imperatorin, meranzin and meranzin hydrate, respectively. The presence of modifiers significantly affected the extraction efficiency: the highest extraction efficiency of the three coumarins was obtained with ethanol as modifier.     

A malonic acid ester derivative of naringin in grapefruit

A malonic acid ester derivative of the flavanone naringin was abundant in the young leaves and fruits of grapefruit plants, but not in the mature leaves and fruits. After isolation, the structure of this compound was established as naringin 6″-malonate (naringenin 72″-O-- -rhamnosyl)-β- -glucoside 6″-malonate).     

Supercritical fluid extraction of lipids from the heterotrophic microalga Crypthecodinium cohnii

Microalgae biomass can be a feasible source of ω‐3 fatty acids due to its stable and reliable composition. In the present study, the Crypthecodinium cohnii growth and docosahexaenoic acid (DHA, 22:6ω3) production in a 100 L glucose‐fed batch fermentation was evaluated. The lipid compounds were extracted by supercritical carbon dioxide (SC‐CO₂) from C. cohnii CCMP 316 biomas, was and their fatty acid composition was analysed. Supercritical fluid extraction runs were performed at temperatures of 313 and 323 K and pressures of 20.0, 25.0 and 30.0 MPa. The optimum extraction conditions were found to be 30.0 MPa and 323 K. Under those conditions, almost 50% of the total oil contained in the raw material was extracted after 3 h and the DHA composition attained 72% w/w of total fatty acids. The high DHA percentage of total fatty acids obtained by SC‐CO₂ suggested that this extraction method may be suitable for the production of C. cohnii value added products directed towards pharmaceutical purposes. Furthermore, the fatty acid composition of the remaining lipid fraction from the residual biomass with lower content in polyunsaturated fatty acids could be adequate for further uses as feedstock for biodiesel, contributing to the economy of the overall process suggesting an integrated biorefinery approach.     

超临界萃取技术及其在食品工业中的应用进展

本文概述了超临界二氧化碳萃取技术,简要介绍了其在食品工业中的最新运用动态,并对超临界二氧化碳萃取技术作了展望。     

Uptake of 14C-gibberellic acid by mature grapefruit (Citrus paradisi Macf.) as affected by relative humidity and method of application

Effects of the method of application and relative humidity on the uptake of ¹⁴C-gibberellic acid (¹⁴C-GA₃) by mature grapefruit (Citrus paradisi Macf.) were examined. Uptake was higher when ¹⁴C-GA₃ was applied as a 'drying-out' solution than as a 'non-drying' solution. When ¹⁴C-GA, was applied by the 'drying-out' method, which closely imitates field conditions, rates of uptake were very high while the solution was drying out and during the first few hours after drying. Uptake from the dry residue continued in decreasing rates till the end of the experiment (72 h). Uptake from the dry residue was higher when fruits were incubated at 100% than at 50% relative humidity (RH). Transfer of fruits from 50% to 100% RH as late as 48 h after drying still increased the rate of uptake. Drying-out treatment solutions produced higher uptake rates with neutral (pH 7) as well as acid (pH 4) treatment solutions, and in the presence of triton B-1956, Triton X-100 or L-77 surfactants.     

超临界流体萃取——高效液相色谱法测定百合中秋水仙碱

分别用超临界二氧化碳流体和有机溶剂萃取百合中的秋水仙碱,然后用高效液相色谱法直接测定萃取物中秋水仙碱的含量,从而测得百合中秋水仙碱的含量。超临界流体萃取的条件是：用乙醇作提携剂,萃取压力为18MPa,萃取温度为40℃,高效液相色谱测定条件为：ODS柱,甲醇：磷酸二氢钾溶液作流动相,检测波长为220nm,此法快速,简便,准确,可应用于秋水仙碱原料,制剂及其它植物中秋水仙碱含量的测定。     

Combining supercritical fluid extraction of soil herbicides with enzyme immunoassay analysis

Supercritical fluid extraction (SFE) of soil herbicides followed by enzyme immunoassay analysis (EIA) is explained in a step-by-step process. Extracted herbicides, include 2,4-D, simazine, atrazine, and alachlor. The herbicide, trifluralin was not successfully analyzed by EIA because of crossreacting metabolites. Problems with SFE, including uneven packing of cells, leaks, uneven flow and clogging, can largely be eliminated as the method parameters are optimized. It was necessary to add modifiers including methanol or acetone to the SF CO₂ to increase the solubility of the analytes. Detection limits of 2.5 ng/g soil for atrazine and alachlor and 15 ng/g soil for simazine and 2,4-D without concentration of the sample were achieved. Recoveries above 80% and relative standard deviations (RSDs) less than 15% for 2,4-D simazine, atrazine and alachlor were achieved. Atrazine and alachlor recoveries were above 90% with RSDs below 10%. Forty soil samples could be extracted and analyzed in an 8-h day.     

地鳖虫活性物质的超临界CO_2萃取及其药效

应用超临界流体萃取技术萃取地鳖虫Eupolyphaga sinensisWalker活性物质,采用三因素三水平正交试验方案,考察压力、温度、时间等参数对萃取地鳖虫活性物质萃取量的影响。同时,对萃取产物与水提物进行药效比较。结果表明,在试验设计范围内,萃取压力18 MPa、温度55℃、时间90 min为最佳工艺参数组合,地鳖虫活性物质萃取量最大能达到62.50 mg/g,影响萃取量三因素主次关系为压力>温度>时间。地鳖虫超临界萃取产物对镇痛、消炎和抗凝血有较好的效果,相对于水提物有更好的发展潜力。     

Rapid techniques for the extraction of vitamin E isomers from Amaranthus caudatus seeds: ultrasonic and supercritical fluid extraction

Supercritical fluid extraction (SFE) of seeds of Amaranthus caudatus (Amaranthaceae) and the use of ultrasound as a co-adjuvant in the extraction process were compared with methods traditionally used in the extraction of tocopherols and fatty acids. The use of readily available ultrasound equipment as an adjunct to the classical methods employed for the extraction of tocols provided qualitatively acceptable results more rapidly and more economically. SFE gave quantitatively better yields in shorter times, with solvent-free extracts obtained under conditions that minimised the degradation of thermolabile components. No significant variations were observed in the profile of the fatty acids extracted from amaranth oil by SFE or other methods, thus confirming the qualitative comparability of the faster supercritical extraction with the more time-consuming classical techniques even when processed with the aid of ultrasound.     

Alpinia oxyphylla Miq. bioactive extracts from supercritical fluid carbon dioxide extraction

In this study, supercritical fluid carbon dioxide extraction technology was developed to gain the active components from a native plant, Alpinia oxyphylla Miq. We studied the biological effects of A. oxyphylla extracts via multiple assays and demonstrated bio-functions at various concentration ranges. Investigations of A. oxyphylla extracts indicated that anti-oxidative properties in dose-dependant manners on radical scavenging activities, reducing power and metal chelating power. The cultured human normal peripheral blood mononuclear cells (PBMCs) were used to test the properties of the extracts in inflammatory cytokine release, and the data did not induce inflammatory molecule releases from un-stimulated PBMCs. A. oxyphylla extracts were able to induce Th1 cytokine IFN-γ released, but not Th2 cytokine IL-13, showing an enhanced anti-bacterial/viral immune function without possible allergic response mediated by IL-13. The extracts also had in vitro mushroom tyrosinase inhibition and cellular tyrosinase melanin decreasing activities in B16F10 cells. In addition, the cell proliferation assay illustrated anti-growth and anti-migration effects in dose-dependent manners of the extracts on human skin melanoma cells, A375 and A375.S2, indicating that the extracts exerted the anti-cancer properties. To our knowledge, this was the first report presenting these bioactivities on A. oxyphylla extracts including antioxidant, anti-inflammation, de-pigmentation and anti-melanoma     

Characterization of the wound-induced material in Citrus paradisi fruit peel by carbon-13 CP-MAS solid state NMR spectroscopy

Grapefruit, Citrus paradisi, were injured, inoculated with Penicillium digitatum and incubated under conditions favourable for the accumulation of defence related material. Histochemical examination revealed that tissues adjacent to inoculated injuries contained phloroglucinol-HCl (PG-HCl) reactive material. Solvent washed cell wall preparations of intact and injured-inoculated peel were further purified using a mixture of cell wall degrading enzymes. Samples from injured inoculated tissue contained PG-HCl reactive globular material in addition to the fragments of xylem and cuticle found in controls. The principal chemical moieties of the material that accumulates in grapefruit injuries during wound-healing were studied by solid state 13C cross-polarization magic angle spinning NMR. A complete assignment of the NMR signals was made. From the analysis evidence was found that cellulose and hemicellulose are the biopolymers present in the intact peel samples, in addition, relevant quantities of cutin were found in the residues of enzyme digest. The NMR difference spectrum intact- wounded peels showed resonances which were attributed to all major functional groups of the aromatic-aliphatic suberin polyester of new material produced by the wounds. Information on the latter polyester was obtained by analyzing the T(1)rho (1H) relaxation.     

Neuroprotective effect of Citrus kawachiensis (Kawachi Bankan) peels,a rich source of naringin,against global cerebral ischemia/reperfusion injury in mice

Cerebral ischemia/reperfusion is known to induce the generation of reactive oxygen species and inflammatory responses. Numerous studies have demonstrated that naringin (NGIN) has anti-oxidant and anti-inflammatory properties. We previously reported that Citrus kawachiensis contains a large quantity of NGIN in its peel. In the present study, we orally (p.o.) administered dried peel powder of C. kawachiensis to mice of a transient global ischemia model and found in the hippocampus region that it 1) suppressed neuronal cell death, 2) reversed the reduction in the level of phosphorylated calcium-calmodulin-dependent protein kinase II, 3) had the tendency to reverse the reduction in the level of glutathione, and 4) blocked excessive activation of microglia and astrocytes. These results suggested that the dried peel powder of C. kawachiensis had a neuroprotective effect against ischemic brain via anti-oxidative and anti-inflammatory effects. We also showed that these effects of the dried peel powder were more powerful than those obtained with a comparable amount of NGIN alone.     

Supercritical CO(2) fluid extraction of crystal water from trehalose dihydrate. Efficient production of form II (T(alpha)) phase

Form II is a kind of metastable crystalline form of trehalose anhydrate, and it is easily converted to the dihydrate crystal by absorbing water in moist atmosphere at room temperature (Akao et al., Carbohydr. Res. 2001, 334, 233-241). It can be utilized as an edible and nontoxic desiccant, and thus its efficient production from the dihydrate is significant from a viewpoint of industrial applications. In this study, we attempt to extract crystal water from the dihydrate using supercritical CO(2). We examine the dependence of extraction efficiency on the extraction time, the temperature and pressure of the fluid. Then, FTIR measurements are carried out to detect the extracted water and to identify the polymorphic phase of the sugar sample after the extraction treatment. In particular, the so-called first derivative euclidean distance analysis for IR spectra is shown to be quite useful for the structural identification. Consequently, we demonstrate that form II is produced from the dihydrate through supercritical CO(2) fluid extraction if appropriate temperature and pressure conditions (around 80 degrees C and 20 MPa) are maintained.     

代代花挥发油的超临界萃取及其在烟草中的应用

为了开发新的天然烟用香料,采用超临界流体萃取技术萃取代代花并优化了萃取工艺,GC-MS对挥发油成分进行了分离鉴定,并对其进行了卷烟加香试验.结果表明:①超临界萃取代代花的最佳工艺为:萃取压力40 MPa、萃取温度50℃萃取时间15 min、改性剂为20%乙醇;②代代花挥发油中共鉴定出45种挥发性成分,主要成分为柠檬烯、...     

Optimisation of supercritical fluid extraction of indole alkaloids from Catharanthus roseus using experimental design methodology--comparison with other extraction techniques

Response surface modelling, using MODDE 6 software for Design of Experiments and Optimisation, was applied to optimise supercritical fluid extraction (SFE) conditions for the extraction of indole alkaloids from the dried leaves of Catharanthus roseus. The effects of pressure (200-400 bar), temperature (40-80 degrees C), modifier concentration (2.2-6.6 vol%) and dynamic extraction time (20-60 min) on the yield of alkaloids were evaluated. The extracts were analysed by high-performance liquid chromatography and the analytes were identified using ion trap-electrospray ionisation-mass spectrometry. The method was linear for alkaloid concentration in the range 0.18-31 microg/mL. The limits of detection and quantification for catharanthine, vindoline, vinblastine and vincristine were 0.2, 0.15, 0.1 and 0.08 microg/mL and 2.7, 2.0, 1.3 and 1.1 microg/g, respectively. The dry weight content of major alkaloids in the plants were compared using different extraction methods, i.e. SFE, Soxhlet extraction, solid-liquid extraction with sonication and hot water extraction at various temperatures. The extraction techniques were also compared in terms of reproducibility, selectivity and analyte recoveries. Relative standard deviations for the major alkaloids varied from 4.1 to 17.5% in different extraction methods. The best recoveries (100%) for catharanthine were obtained by SFE at 250 bar and 80 degrees C using 6.6 vol% methanol as modifier for 40 min, for vindoline by Soxhlet extraction using dichloromethane in a reflux for 16 h, and for 3',4'-anhydrovinblastine by solid-liquid extraction using a solution of 0.5 m sulphuric acid and methanol (3:1 v/v) in an ultrasonic bath for 3 h.     

超临界CO_2萃取冬虫夏草子座挥发性成分的GC-MS研究

报道冬虫夏草挥发性成分的组成,为其进一步的研究工作奠定基础。采用超临界CO2萃取法从冬虫夏草子座中提取挥发性成分,气相色谱-质谱联用技术对其化学成分进行分析。超临界流体萃取物共鉴定了39种组分,占总馏出组分的86.6%以上,占色谱总馏出峰面积的98.56%以上。已鉴定组分中,含量最高的为油酸,相对含量25.6%;其次为亚油酸,相对含量22.67%;再次为棕榈酸11.86%。超临界CO2萃取法能更真实、全面的反映药材中的化学成分,适合于珍稀中药材相关组分的测定。     

Supercritical fluid extraction of algae enhances levels of biologically active compounds promoting plant growth

The aim of this research was to screen plant growth biostimulant properties of supercritical CO₂ macroalgal extracts. To this end secondary metabolites were isolated from the biomass of marine macroalgae from the Baltic Sea (species of Polysiphonia, Ulva and Cladophora). Chemical characteristics of the algal extracts were determined by inductively coupled plasma atomic emission spectroscopy for inorganic constituents and high-performance liquid chromatography and spectrophotometry for organic constituents. Inorganic (macro- and microelements) and organic (plant hormones: auxins and cytokinins; polyphenols) compounds were detected in the extract. Algal extracts were tested primarily on garden cress (Lepidium sativum L.; Brassicaceae) and wheat (Triticum aestivum L.; Poaceae). The extracts enhanced chlorophyll and carotenoid content in plant shoots, as well as root thickness and above-ground biomass. The most effective method of application of the extract was by foliar feed on cress and seed maceration for wheat. Algal extracts obtained by supercritical fluid extraction (SFE) were found to be a novel natural source of compounds, stimulating growth of cultivated plants. However, field trials will be required to show that the extracts can act as plant biopesticides and growth biostimulants.     

Mathematical modeling and study of mass transfer parameters in supercritical fluid extraction of fatty acids from Trout powder

Mathematical modeling of fatty acids (FAs) extraction from Trout powder by supercritical carbon dioxide was performed in the present work. Trout powder with its low cost contains high amount of essential FAs and it is commonly available as a proper source of FAs. The effect of process parameters, such as pressure (25, 28, 31, 34 and 37 MPa) and temperature (310, 318 and 326 K) of extraction and void fraction of the bed (0.25, 0.35 and 0.45, v/v) on the yield of FAs extraction was examined in a series of experiments conducted in a laboratory scale apparatus. The results indicated a significant increase of extraction yield with an increase of pressure from 25 to 34 MPa, but working at the higher pressure (37 MPa) caused reduction of the extract. Increasing the temperature higher than 318 K revealed significant reduction of the FAs yield and increasing the bed void fraction from 0.25 to 0.45 showed enhancement of the extraction.

The mathematical model was developed considering diffusion-controlled regime in the particle and film mass transfer resistance around the particle with axial dispersion of the bulk phase at dynamic conditions. Henry law was used to describe the equilibrium state of solid and fluid phases. The proposed mass balance equations were numerically solved using implicit finite difference method and the model parameters were correlated using the experimental results of the outlet FAs concentration in the oil extracted at dynamic conditions. Well-known Nelder–Mead method was applied to estimate the four parameters of the model, namely, mass transfer coefficient (k_f), axial dispersion coefficient (D_ax) in the bulk phase, effective diffusivity (D_eff) into the pores and Henry coefficient (H). In the range of studied conditions, the higher extraction efficiency with higher pressure resulted lower correlated H, although the temperature increasing which showed a retrograde phenomena in the FAs yield, revealed H passing though a minimum.     

Chiral HPLC separation and CD spectra of the C-2 diastereomers of naringin in grapefruit during maturation

Naringin is the chief flavanone glycoside of grapefruit (Citrus paradisi). It is responsible for part of the bitter taste of the fruit and can cause the inhibition of some cytochrome P450s. The direct separation of (2R)- and (2S)-naringin in the albedo of grapefruits was obtained in normal phase HPLC mode using Chiralcel OD as chiral stationary phase and n-hexane/ethanol with 0.1% of TFA as mobile phase. Chiralpak AD was almost ineffective in the separation. This procedure was used to evaluate the stereochemistry at C-2 during maturation of the grapefruit. The CD curves of (2R)- and (2S)-naringin isolated by semipreparative chiral HPLC were determined and the elution order of the chromatographic peaks was related to the absolute C-2 configuration. Partial resolution of the C-2 diastereomers of narirutin was obtained on Chiralpak AD.     

Quantification of seed oil from species with varying oil content using supercritical fluid extraction

Introduction: The quantity and composition of seed oil affects seed viability and storability and hence the value of a species as a resource for nutrition and plant conservation. Supercritical fluid extraction with carbon dioxide (SFE‐CO₂) offers a rapid, environmentally friendly alternative to traditional solvent extraction. Objective: To develop a method using SFE‐CO₂ to quantify the seed oil content in a broad range of species with high to low oil contents. Methodology: Seed oil was extracted using SFE‐CO₂ from four crop species representing high, medium and low oil content: Helianthus annuus, Asteraceae, with ca. 55% oil; Brassica napus, Brassicaceae, with ca. 50% oil; Glycine max, Fabaceae, with ca. 20% oil; and Pisum sativum, Fabaceae, with ca. 2% oil. Extraction pressures of 5000, 6000 and 7500 psi and temperatures of 40, 60 and 80°C were examined and a second step using 15% ethanol as a modifier included. Oil yields were compared with that achieved from Smalley Butt extraction. The optimised SFE‐CO₂ method was validated on six species from taxonomically distant families and with varying oil contents: Swietenia humilis (Meliaceae), Stenocereus thurberi (Cactaceae), Sinapis alba (Brassicaceae), Robinia pseudoacacia (Fabaceae), Poa pratensis (Poaceae) and Trachycarpus fortunei (Arecaceae). Results: The two‐step extraction at 6000 psi and 80°C produced oil yields equivalent to or higher than Smalley Butt extraction for all species, including challenging species from the Brassicaceae family. Conclusion: SFE‐CO₂ enables the rapid analysis of seed oils across a broad range of seed oil contents. Copyright © 2008 John Wiley & Sons, Ltd.