Isolation of chlorophylls and carotenoids from freshwater algae using different extraction methods

Usually marine algae are an excellent source of pigments for different commercial sectors. Freshwater macroalgae can be exploited as a good source of biologically active compounds provided an appropriate extraction method is developed. The efficiency of four methods, like microwave‐assisted (MAE), ultrasound‐assisted extraction (UAE), supercritical fluid extraction (SFE) with ethanol as a co‐solvent, as well as conventional Soxhlet extraction were studied in the same conditions (time, solvent and temperature) for the recovery of chlorophylls and carotenoids from three freshwater green algae species: Cladophora glomerata, Cladophora rivularis and Ulva flexuosa. UV‐Vis spectrophotometry was used to determine chlorophyll a, chlorophyll b and total carotenoid content in obtained extracts. The results of this study showed that the advantages of novel extraction techniques (MAE and UAE) include higher yield and, in consequence, lower costs compared to traditional solvent extraction techniques. These methods were much more efficient in freshwater green algae pigment recovery than the classic Soxhlet extraction as well as SFE.     

Optimizing a continuous flow lipid extraction system (CFLES) used for extracting microalgal lipids

A laboratory‐made continuous flow lipid extraction system (CFLES) was devised to extract lipids from microalgae Nannochloropsis sp., a potential feedstock for biodiesel fuel, with a focus to assess the workable temperatures and pressures for future industrial applications. Using conventional solvents, the CFLES recovered 100% of the lipids extracted with conventional Soxhlet extraction. The optimum temperature and pressure were found to be 100 °C and 50 psi, respectively; conditions significantly lower than those normally used in pressurized liquid extractions requiring specialized equipment. Approximately 87% of the extracted oil was successfully transesterified into biodiesel fuel (fatty acid methyl esters). Preliminary calculations based on the tested lab‐scale system indicated savings in energy, solvent consumption, and extraction time as 96%, 80%, and more than 90%, respectively, as compared to Soxhlet extraction. However, the true cost savings can only be assessed at scaled up level. Energy efficiency of CFLES was calculated as 48.9%. Residual water (~70%) in the biomass had no effect on the extraction performance of CFLES, which is expected to help the process economics at scaled up application. The effect of temperature and pressure on the fatty acids profile of Nannochloropsis sp. is also discussed. Based on the existing literature, the authors believe that a pressurized liquid extraction system with continuous solvent flow has not been reported for lipid extraction from Nannochloropsis sp.     

正交试验法优选烟草中辅酶Q10的匀浆提取工艺

以烟草叶片为原料,用正交试验法优化了烟草中辅酶Q10的匀浆提取工艺,考察了匀浆时间、乙醇体积分数、液料比和提取次数4个因素对辅酶Q10提取率的影响,确立了烟草中辅酶Q10的优化匀浆提取工艺条件为:提取溶剂为85%乙醇,匀浆时间6 min,液料比9∶1(mL/g),提取次数2次。将该法与索氏提取进行了对比。结果表明,匀浆提取烟草中辅酶Q10的提取率为12.82μg·g-1,与索氏提取的提取率相当,但匀浆提取所用提取时间短,提取溶剂用量少,因此匀浆法具有明显的优势。     

桦褐孔菌提取物抗氧化活性研究

以乙酸乙酯和甲醇为提取剂,采用索氏提取法,剩余残渣采用热水浸提,最终得到桦褐孔菌不同极性提取物,对其DPPH自由基、羟基自由基及超氧阴离子自由基清除活性作用进行了研究,确定桦褐孔菌的抗氧化能力,为深入研究和开发桦褐孔菌功能性食品奠定理论基础。实验结果表明桦褐孔菌具有较好的抗氧化活性,其中乙酸乙酯提取物的DPPH自由基清除率、羟基自由基清除率和超氧阴离子自由基清除率均高于其他两组分及BHT,桦褐孔菌提取物有望成为功能性食品组分中合成抗氧化剂的天然替代品。     

Determination of the active constituents in Arnebia euchroma (Royle) Johnst. by ionic liquid-based ultrasonic-assisted extraction high-performance liquid chromatography

Shikonin and β,β'-dimethylacrylshikonin in Arnebia euchroma (Royle) Johnst. were extracted by ionic liquid-based ultrasonic-assisted extraction (IL-based UAE) and determined by high-performance liquid chromatography (HPLC). The dried powder of A. euchroma (Royle) Johnst. was mixed with a room temperature ionic liquid [C(6)MIM][BF(4)] to form a suspension, and then the ultrasonic extraction was performed in a water bath at ambient temperature. The calibration curve showed good linear relationship (r>0.9998) in the concentration range of 1.75-140 μg/mL for shikonin and 2.15-1360 μg/mL for β,β'-dimethylacrylshikonin. The recoveries were between 69.79% and 82.35%. The IL-based UAE is free of volatile organic solvents, and consumes less sample, time and solvent, compared with regular ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.     

A Rapid Method,Combining Microwave-Assisted Extraction and Gas Chromatography-Mass Spectrometry with a Database,for Determining Organochlorine Pesticides and Polycyclic Aromatic Hydrocarbons in Soils and Sediments

A rapid method for determining organochlorine pesticides and polycyclic aromatic hydrocarbons in soils and sediments was developed to allow pollution surveys to be performed in emergencies. The method involves microwave-assisted extraction and uses an automated identification/quantification system with a gas chromatography mass spectrometry database. A sample (3 g) is extracted with a 3:2 v/v hexane:water mixture (10 mL) for 30 min using a microwave-assisted extraction system at 120°C. The hexane extract is then cleaned using silica gel, then analyzed by gas chromatography mass spectrometry. The total analysis time is approximately 4 h. The precision of the quantitative results and accuracy of the analyte identification were determined. The total analyte concentrations were generally comparable to (61%–110% of) the concentrations determined using a Soxhlet extraction method, but the concentrations of individual high-molecular-weight polycyclic aromatic hydrocarbons were unacceptably low compared with the concentrations determined using the Soxhlet method. However, these compounds (e.g., benzo(ghi)perylene and indeno(1,2,3-cd)pyrene) were subsequently efficiently extracted using a hexane:water:ethanol mixture. The accuracy of identification was evaluated using accurate masses determined by gas chromatography time-of-flight mass spectrometry, and the mass error was 2 ppm for 21 of the 22 compounds identified using the new method.     

超声辅助索氏提取忍冬果实中绿原酸的工艺优化

利用超声辅助索氏提取的方法从忍冬果实中提取绿原酸。单因素和正交试验表明,影响绿原酸提取率的主次顺序为:超声温度>乙醇浓度>超声时间>索氏提取时间>液料比;提取的最佳条件为:超声温度60℃,超声时间40min,乙醇浓度70%,液料比(mL∶g)30∶1,索氏提取时间2.5h。忍冬果实中绿原酸的提取率为2.95%;柱色谱分离纯化后的绿原酸红外谱图和标准品的红外谱图基本一致。本研究表明,超声辅助索氏提取忍冬果实中绿原酸的方法,缩短了提取时间,绿原酸提取率高。对忍冬果实的开发利用具有重要的指导意义。     

Silene vulgaris subsp. macrocarpa leaves and roots from Morocco: assessment of the efficiency of different extraction techniques and solvents on their antioxidant capacity,brine shrimp toxicity and phenolic characterization

Abstract

This study was undertaken to investigate the effect of various solvents and techniques on the extractability of antioxidant compounds, particularly phenolics, from leaves and roots of Silene vulgaris subsp. macrocarpa grown wild in Morocco. Maceration and hot extraction with methanol or water and Soxhlet ethanol extraction were utilized. Aimed at establishing the potential safety of the extracts, Artemia salina lethality bioassay was performed. All the extracts were found to be non-toxic, except for the leaf Soxhlet ethanol. The antioxidant potential of the extracts was evaluated in vitro by DPPH, reducing power, and ferrous ions chelating activity assays. The leaf extracts displayed noticeable radical scavenging and chelating activities, and maceration with methanol (Mac-MeOH) resulted the most suitable extraction method for an effective recovery of antioxidants; further, the root Mac-MeOH extract demonstrated good chelating properties (IC₅₀ = 335.49?±?0.70?µg/mL). Thus, leaf and root Mac-MeOH extracts were subjected to phytochemical investigations. The total phenolic, flavonoid and condensed tannin content was determined spectrophotometrically. Thirteen polyphenolic compounds were positively identified, by HPLC-PDA-ESI-MS, in the leaf extract for the first time, with p-coumaric acid derivatives being the most abundant ones (81%), whereas only catechin and procyanidin B1 were found in the root extract.     

Determination of aconitine,hypaconitine and mesaconitine in urine using hollow fiber liquid-phase microextraction combined with high-performance liquid chromatography

Hollow fiber liquid-phase microextraction (HF-LPME) coupled with high-performance liquid chromatography was used to simultaneously determine three Aconitum alkaloids, including aconitine (AC), hypaconitine (HA) and mesaconitine (MA) in human urine sample. Analytes were extracted from 5 mL urine sample containing 1.0 mmol/L NaOH into 1-octanol membrane phase impregnated in the pores of hollow fiber wall, and then back extracted into acidified aqueous solution in the lumen of the hollow fiber. After extraction, 10 μL of the acceptor phase was analyzed directly by HPLC. In this method, some important extraction parameters, such as organic solvent, extraction time, stirring rate, pH of donor phase and acceptor phase, temperature, and the volume of acceptor phase were optimized. This method provided 98- to 288-fold enrichment factors within 60 min of extraction and good repeatability with RSDs of 0.99–7.22%. The calibration curves were linear over the ranges of 16.0–128.0 μg/L for AC, 11.0–88.0 μg/L for HA and 8.1–64.8 μg/L for MA in human urine sample, with correlation coefficients of 0.9949, 0.9969 and 0.9904, respectively. Limits of detection were from 0.7 to 1.5 μg/L, and recoveries from spiked urine sample varied from 84.4% to 106.2% for AC, 77.3% to 85.6% for HA and 90.1% to 100.8% for MA.     

Microwave-assisted extraction of glycyrrhizic acid from licorice root

In the present study, a microwave-assisted extraction (MAE) technique has been developed for the extraction of glycyrrhizic acid (GA) from licorice root. Various experimental conditions, such as extraction time, different ethanol and ammonia concentration, liquid/solid ratios, pre-leaching time before MAE and material size for the MAE procedure were investigated to optimize the efficiency of the extraction. Under appropriate MAE conditions, such as extraction times of 4-5min, ethanol concentrations of 50-60% (v/v), ammonia concentrations of 1-2% (v/v) and liquid/solid ratios of 10:1(ml/g), the recovery of GA from licorice root with MAE was equivalent with conventional extraction methods. Those methods include extraction at room temperature (ERT), the traditional Soxhlet extraction, heat reflux extraction and ultrasonic extraction. Due to the considerable savings in time and solvent, MAE was more effective than the conventional methods. This novel method is suitable for fast extraction of GA from licorice root.     

Optimisation of a microwave-assisted method for extracting withaferin A from Withania somnifera Dunal. using central composite design

Introduction – Recently, there have been growing attention on the modification and optimisation of new extraction and quantification methods, caused by the lack of environmentally friendly methodologies for the extraction of phytochemicals from complex matrices. In the case of pharmaceutical compounds, not only the extraction procedure but also the analysis method should be efficient, precise, fast and easy. Objectives – The essential pharmaceutical characteristics and trace concentration of withanolides led us to modify and optimise the previously reported extraction and quantification procedure for withaferin A (WA) as a candidate for withanolides. Matrial and methods – The WA from the air‐dried aerial part of Withania somnifera Dunal. was extracted using a microwave‐assisted extraction (MAE) technique. Four variables affecting the extraction procedure were optimised using the central composite design approach. The method of high‐performance thin‐layer chromatography assay was validated and applied for the quantification of each experiment. Results – The optimum values of factors were: extraction time (150 s), extraction temperature (68°C) and 17 mL of methanol : water in the ratio 25 : 75 as extracting solvent. The solvent system consisted of ethyl acetate : toluene : formic acid : 2‐propanol (7.0 : 2.0 : 0.5 : 0.5, v/v/v/v), and densitometric scanning at 220 nm was applied for the analysis. The dynamic linear range, LOD, LOQ and recovery with the inter‐day, and intra‐day RSDs of the developed method indicated the validity of the method. Conclusion – A pressurised MAE method for extracting WA from the plant's aerial part was optimised using factorial‐based design. The net effect of time, temperature, solvent volume and its ratio suggests that the yield of WA increases until each factor reaches its optimum value, and decreases with further increase in temperature or solvent ratio. Copyright © 2010 John Wiley & Sons, Ltd.     

Extraction of rapamycin (sirolimus) from Streptomyces rapamycinicus using ultrasound

The study was designed to investigate the use of ultrasound-assisted extraction (UAE) of rapamycin (sirolimus) from bacterial strain of Streptomyces rapamycinicus NRRL 5491. To achieve the maximum extraction yield, various parameters were optimized which include S. rapamycinicus (10?g) of biomass in toluene (50?mL), temperature (20°C), acoustic intensity (35.67?W/cm²), and duty cycle (40%) for 4?min extraction time with probe tip length of 0.5?cm dipped into extraction solvent from the surface. The maximum extraction yield 60.15?±?0.01?mg/L was attained under the mentioned optimum parameters. The use of ultrasound for the extraction of rapamycin shows about twofold increase in the yield as compared to the conventional solid–liquid extraction (29.7?±?0.2?mg/L). The study provides the effective UAE technique to produce potential value-added products.     

Simultaneous determination of flavonoids and phenylethanoids in the flowers of Verbascum densiflorum and V. phlomoides by high‐performance liquid chromatography

Introduction – Mullein (Verbascum) flowers are highly valued herbal drugs used in the treatment of inflammation, asthma, spasmodic coughs and other respiratory tract diseases. Their phenolic constituents are considered to be responsible for the anti‐inflammatory and antimicrobial activity of the herb. However, knowledge about the contents of phenolics in flowers is limited and no HPLC method for their analysis is available. Objective – To develop and validate an RP‐HPLC‐UV method for the simultaneous determination of eight flavonoids and two phenylethanoids in the flowers of Verbascum densiflorum and V. phlomoides. Methodology – HPLC separation was accomplished on a C₁₈ Lichrosphere 100 column (5 µm, 250 mm × 4.6 mm, i.d.) with an acetonitrile gradient elution using aqueous 0.5% (w/v) orthophosphoric acid solution containing 1% (v/v) tetrahydrofurane. Results – All the calibration curves showed good linear correlation coefficients (r > 0.997) over the wide test ranges. The relative standard deviation of the method was less than 3.4% for intra‐ and inter‐day assays, and the average recoveries were between 93.5 and 101.9%. High sensitivity was demonstrated with detection limits of 0.062–0.083 µg/mL for flavonoid aglycones, 0.156–0.336 µg/mL for flavonoid glycosides and 0.390–0.555 µg/mL for phenylethanoids. The flower samples of V. phlomoides were found to contain high levels of diosmin and tamarixetin 7‐rutinoside (2.327–2.392% of dry weight), whereas verbascoside (0.688–0.742% of dry weight) and luteolin 7‐glucoside (0.204–0.279% of dry weight) dominated in the V. densiflorum flower. Conclusion – The HPLC method established is appropriate for the quality assurance and the differentiation of V. phlomoides and V. densiflorum samples. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of fatty acids in A. szechenyianum Gay. by microwave‐assisted extraction and gas chromatography‐mass spectrometry

Introduction – Aconitum szechenyianum Gay. is a traditional Chinese medicinal herb with the detumescent and styptic effects and antitumor activity. There have been only a few researches on its chemical components, but no detailed report has appeared on its fatty acids. Objective – To develop a simple and effective method for the extraction of fatty acids from A. zechenyianum Gay. and then to investigate the fatty acid components. Methodology – Microwave‐assisted extraction (MAE) was optimized with response surface methodology, and the fatty acid compositions of extract were determined by GC–MS with previous derivatisation to fatty acid methyl esters (FAMEs). The results were compared with that obtained by classical Soxhlet extraction (SE). Results – Compared with SE, MAE showed significantly higher fatty acid yields, shorter extraction time, and lower energy and solvent consumption. The major fatty acids in A. szechenyianum Gay. are linoleic acid, palmitic acid, linolenic acid, oleic acid and stearic acid, and the unsaturated fatty acids occupy 66.4% of the total fatty acids. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of extraction method on the yield of furanocoumarins from fruits of Archangelica officinalis Hoffm

Optimal conditions for the extraction and analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm. have been determined. The following extraction methods were used: exhaustive extraction in a Soxhlet apparatus, ultrasonication at 25 and 60 degrees C, microwave-assisted solvent extraction in open and closed systems, and accelerated solvent extraction (ASE). In most cases the yields of furanocoumarins were highest using the ASE method. The effects of extracting solvent, temperature and time of extraction using this method were investigated. The highest yield of furanocoumarins by ASE was obtained with methanol at 100-130 degrees C for 10 min. The extraction yields of furanocoumarins from plant material by ultrasonication at 60 degrees C and microwave-assisted solvent extraction in an open system were comparable to the extraction yields obtained in the time- and solvent-consuming exhaustive process involving the Soxhlet apparatus.     

核桃楸树皮总黄酮提取方法及工艺研究

对核桃楸树皮总黄酮提取方法及相关影响因素进行探讨。以总黄酮含量为指标,分别考察常规提取法、超声波提取法、回流提取法、索氏提取法对提取率的影响,以及溶剂的种类、浓度与温度对提取率的影响。结果表明,超声波提取法的总黄酮提取率最高;使用60%乙醇在60℃时的总黄酮提取率最高。     

Tubercidin: Its Conversion to 5′-Amino-5′-deoxytubercidin

A method for the determination of allethrin and other pesticides in mosquito coils was developed by the combination of shaking extraction and gas chromatography (GC). Allethrin and other pesticides were adequately extracted by shaking for only half an hour with a mixture of toluene and 99% formic acid (5:1). This shaking extraction method was more effective for shortening the extraction time compared with the Soxhlet extraction method, and accurate determination was achieved without the interference from inert materials in the mosquito coils. The recovery of allethrin in various contents from the coils was 96.6 to 97.1%, with a 1.2 to 1.5% coefficient of variation. Furthermore, the recoveries of other pesticides and synergists from the coils were 94 to 102% by this shaking extraction method.     

Preconcentration of pharmaceuticals residues in sediment samples using microwave assisted micellar extraction coupled with solid phase extraction and their determination by HPLC-UV

An analytical method combining microwave assisted micellar extraction (MAME) and solid phase extraction (SPE) has been developed to extract and preconcentrate a selected group of eight pharmaceutical compounds in sediment samples prior to their determination using liquid chromatography with an UV-DAD detector. A non-ionic surfactant, Polyoxyethylene 10 lauryl ether (POLE) was used for the MAME extraction and the different parameters for the optimization process were studied. Then, SPE was used to clean-up and preconcentrate the target analytes in the extract, prior to their determination using HPLC-UV. The method was applied to the determination of the selected pharmaceuticals compounds in several kinds of sediment samples with different characteristics. Relative recoveries for spiked sediment samples were over 70% and relative standard deviations (RSDs) were under 11% for all recoveries tested. Detection limits between 4 and 167ngg(-1) were obtained. The method was validated using Soxhlet extraction procedure.     

Comparative study of turbulent solid-liquid extraction methods for the determination of organochlorine pesticides

The aim of any extraction method in analytical chemistry is to effectively separate the analytes from the matrix with minimal solvent and time required. In this study, a comparison of the classical Soxhlet extraction and some new turbulent solid-liquid extraction techniques, such as fluidized-bed extraction (FBE), modified dive-in fluidized-bed extraction (dive-in FBE), modified dive-in Soxhlet extraction (dive-in SE) and dive-in thimble extraction (dive-in TE) for the determination of organochlorine pesticides (OCPs) was carried out. The turbulent extraction methods were performed by using the fexIKA vario control series extractor and by modification of the extraction system to dive-in technique, respectively. In addition, FBE and dive-in FBE were operated under the same, only for the FBE system established, optimum conditions. For the determination of the analytes a selective clean-up of the extracts followed by a gas chromatography (GC) method with mass spectrometric detection was used. All advanced extraction methods with reduced time and solvent consumption exhibited higher extraction efficiency than the standard procedure, Soxhlet extraction.     

Unequivocal Enantiomeric Identification and Analysis of 10 Chiral Pesticides in Fruit and Vegetables by QuEChERS Method Combined With Liquid Chromatography‐Quadruple/Linear Ion Trap Mass Spectrometry Determination

In this research, 10 chiral pesticides in fruits and vegetables were simultaneously determined using chiral liquid chromatography triple quadrupole‐linear ion trap hybrid mass spectrometry (LC‐QqLIT). The QuEChERS method was applied for sample preparation, and an enhanced product ion (EPI) scan was used to acquire tandem mass spectrometry (MS/MS) spectra for the library search. Parameters including limit of detection (LOD), limit of quantification (LOQ), linearity, relative standard deviation (RSD), and matrix effects were evaluated in five representative matrices (strawberry, leek, cowpea, tomato, and eggplant). Good linearity with coefficient of determination (r²) ≥0.997 was obtained for all 20 enantiomers in these five matrices over the range from 1.0 to 250 µg L^‐1. All the recoveries at 5 and 50 µg kg^‐1 (n = 5) ranged between 70% and 120% with RSD below 20%, indicating satisfactory precision. The LOQ for the enantiomers ranged between 0.05 and 1 µg kg^‐1. Based on the proposed method, 135 commonly consumed fruits and vegetables taken from markets in Guizhou province, China, were analyzed. Enantioselective degradation for the selected chiral pesticides was observed in most of the positive samples. Chirality 27:958–964, 2015. © 2015 Wiley Periodicals, Inc.