Conventional Reflux Extraction Research Articles

A Comprehensive Review on Deep Eutectic Solvents: Their Current Status and Potential for Extracting Active Compounds from Adaptogenic Plants.

Deep eutectic solvents (DESs) have attracted attention from researchers as novel compounds for extracting active substances because of their negligible toxicity, polarity, and ability to be tailored depending on the experiment. In this review, we discuss deep eutectic solvents as a promising medium for the extraction of adaptogenic compounds. In comparison to traditional methods, extraction with the use of DESs is a great alternative to the excessive usage of harmful organic solvents. It can be conducted in mild conditions, and DESs can be designed with different precursors, enhancing their versatility. Adaptogenic herbs have a long medicinal history, especially in Eastern Asia. They exhibit unique properties through the active compounds in their structures, including saponins, flavonoids, polysaccharides, and alkaloids. Therefore, they demonstrate a wide range of pharmaceutical effects, such as anti-inflammatory, antibacterial, and anticancer abilities. Since ancient times, many different adaptogenic herbs have been discovered and are well known, including Panax ginseng, Scutellaria baicalensis, and Schisandra chinensis. Active compounds can be extracted using standard methods, such as hydrolyzation, maceration, and conventional reflux extraction. However, due to the limitations of classical processing technologies, there has been a need to develop new and eco-friendly methods. We focus on the types of solvents, extraction efficiency, properties, and applications of the obtained active compounds. This review highlights the potential of DESs as eco-friendly alternatives for extracting bioactive compounds.

Evaluation of Microwave- and Ultrasound-Assisted Extraction Techniques for Revalorization of Black Chokeberry (Aronia melanocarpa) Fruit Pomace Anthocyanins

Black chokeberry juice production results in a large amount of pomace, which is usually regarded as waste. Nevertheless, it contains significant amounts of anthocyanins, which can be utilized as health-promoting components, but also as food colorants. To take advantage of their benefits, green extraction methods such as microwave-assisted (MAE) and ultrasound-assisted extraction (UAE) are widely used for their isolation. This study aimed to evaluate the effects of MAE and UAE parameters (solvent, treatment time, temperature, or ultrasound amplitude) on the extraction yield of anthocyanins from black chokeberry pomace and to compare the effectiveness of these two green extraction methods with conventional reflux extraction, both in terms of total anthocyanins yield and effects on individual compounds. In both techniques, acidification of the extraction solvent did not show a significant effect on anthocyanin content. For MAE, a temperature increase from 40 to 60 °C positively affected the extraction yield, while 4 min was a substantial treatment time for the extraction. Conversely, UAE required 10 min of treatment time with no effect on amplitude. UPLC ESI-MS2 analysis confirmed the presence of 6 anthocyanins in the obtained extracts, with significantly higher levels of cyanidin-3-O-xyloside and cyanidin-3-O-arabinoside were in ones isolated by green extraction techniques.

Optimization Extraction and Antioxidant Activity of Crude Polysaccharide from Chestnut Mushroom (Agrocybe aegerita) by Accelerated Solvent Extraction Combined with Response Surface Methodology (ASE-RSM).

The present work is conducted to investigate the optimal extraction technology of polysaccharide from chestnut mushroom (Agrocybe aegerita) using a new method based on accelerated solvent extraction combined with response surface methodology (ASE-RSM). The conventional reflux extraction (CRE) method and ultrasonic-assisted extraction (UAE) method were also carried out. Additionally, the in vitro antioxidant activities, including ABTS and DPPH assay, were evaluated. The RSM method, based on a three level and three variable Box–Behnken design (BBD), was developed to obtain the optimal combination of extraction conditions. In brief, the polysaccharide was optimally extracted with water as extraction solvent, extraction temperature of 71 °C, extraction time of 6.5 min, number of cycles of 3, and extraction pressure of 10 MPa. The 3D response surface plot and the contour plot derived from the mathematical models were applied to determine the optimal conditions. Under the above conditions, the experimental value of polysaccharide yield was 19.77 ± 0.12%, which is in close agreement with the value (19.81%) predicted by the model. These findings demonstrate that ASE-RSM produce much higher polysaccharide and consumed environmentally friendly extraction and solvent systems, have less extraction discrimination and shorter time and provide scientific basis for industrialization of polysaccharide extraction. Moreover, it was proved that the polysaccharide had the potential ability to scavenge ABTS and DPPH.

Ionic liquid and ultrasound-assisted extraction of chestnut shell pigment with good hair dyeing capability

To effectively extract the pigment from chestnut shell in a green and efficient way, an eco-friendly and efficient method based on ionic liquid ultrasonic assisted extraction (IL-UAE) was established. The effect of a series of 1-alkyl-3-methyl imidazole ionic liquids on the yield was investigated. The results indicated that the chain length of ionic liquids and the properties of anions and cations had a significant impact on the extraction, and 1-butyl-3-methylimidazolium acetate ([Bmim]OAc) had the best extraction effect. In addition, the concentration of bond breaking agent (sodium dodecyl sulfate, urea), concentration of [Bmim]OAc, liquid-solid ratio, extraction power, time, temperature and other parameters were tested by single factor. Sodium dodecyl sulfate (SDS), urea concentration and liquid-solid ratio were optimized by response surface methodology (RSM). The optimal process conditions were as follows: SDS concentration of 0.44% (w/v), urea concentration of 2.87% (w/v), [Bmim]OAc concentration of 1.07 mol/L, liquid-solid ratio of 36.26 mL/g, ultrasonic power of 350 W, ultrasonic time of 50 min, and ultrasonic temperature of 80 °C, respectively. Under these conditions, the yield was 71.60 mg/g. Compared with the conventional reflux extraction with organic solvents (sodium hydroxide, ethanol), the optimized method improved the yield by 42.24% and 38.70% in a shorter time (50min versus 120min), respectively. The physico-chemical properties of hair dyed with chestnut shell pigment extracted by IL-UAE were compared with those extracted by conventional organic solvents. The results showed that the former showed excellent color intensity, smooth hair surface morphology and low internal damage than the latter. Our results helped to accelerate the high-value applications of chestnut wastes.

Microwave assisted extraction of inositols for the valorization of legume by-products

Currently there is great interest in exploitation of agrofood by-products, such as those from legumes, as source of bioactive ingredients. To that aim, characterization of cyclitol and sugar composition of pods and seeds from different legume species has been carried out. A green Microwave Assisted Extraction (MAE) method was optimized for extraction of bioactive inositols, and both pod and seed yields were compared with those obtained by conventional reflux extraction. A subsequent Saccharomyces cerevisiae treatment was also evaluated for removal of interfering coextracted sugars.myo-Inositol was present in all legume pods and seeds and galactinol in most seeds. chiro-Inositol was found in soybean and basul, whereas outstanding pinitol concentrations were only detected in soybean. The optimized MAE method provided extracts rich in pinitol from soybean pods (41.5–58.0 mg g−1) and seeds (5.3–7.5 mg g−1). Removal of 97% of interfering sugars in MAE soybean pod extracts was achieved by yeast treatment.

Optimization of reflux extraction for cat’s whiskers leaves extract using response surface methodology

Cat?s whiskers (Orthosiphon stamineus) is a medicinal plant which comprises several dynamic pharmacological properties such as anti-inflammatory, antioxidant and antibacterial. In small and medium-scale industries, conventional reflux extraction method is favored as compared to other non-conventional extraction methods due to cost effectiveness and simple operating procedures. In this study, response surface methodology (RSM) was applied to optimize the reflux conditions for extraction of cat?s whiskers leaves in order to achieve a high content of antioxidant activity in the extracts. Central composite experimental design (CCD) with three factors and three levels was employed to consider the effects of the operation conditions. Antioxidant activity of the extracts were based on free radical scavenging activity (DPPH assay) and were analyzed using a UV-Vis spectrophotometer. Based on RSM, the antioxidant activity could be maximized when the operation conditions were 125 ?m for particle size, 1.5:20 for sample-to-solvent ratio, and 2 h for extraction time. Under these optimal conditions, the predicted value of the antioxidant activity was compared with the actual, and the mean error was 0.46%. This indicates the suitability of the model for optimizing the conditions for the reflux extraction of cat?s whiskers leaves.

Optimization of the microwave-assisted extraction characteristics for bioactive compounds from eggplant (Solanum melongena L.)

Eggplant is consumed worldwide as a valuable source of phytochemicals, especially anthocyanin and antioxidants. Here, microwave-assisted extraction (MAE) was applied to optimize the total yield (TY), total anthocyanin content (TAC), total phenolic content (TPC), and radical scavenging activities (DPPH, ABTS, and FRAP) of eggplant. A response surface methodology (RSM) was employed based on a five-factor, three-level central composite design with the ethanol concentration (X1) 55-95% , microwave power (X2: 0-200 W), and extraction time (X3: 30-150 s) as independent process variables. Furthermore, the efficiency of MAE was compared to that of conventional reflux extraction (CRE) in terms of target responses, energy consumption, and CO2 emissions. The highest TY (1.72%), TAC (9.55 mg CE/L), TPC (48.75 mg GAE/100 mL), and antioxidant activities (DPPH: 45.95, ABTS: 46.74, and FRAP: 69.22 mg TE/100 mL) were obtained under the optimum MAE parameters of X1: 70%, X2: 160 W, and X3: 100 s. Moreover, MAE yielded higher target responses than CRE in a faster time with lower energy consumption and CO2 emissions. In conclusion, the application of RSM to evaluate the extraction characteristics of individual components by MAE and CRE revealed MAE as an effective method for the green extraction of target compounds from eggplant.

In Vivo Evaluation of Ethanol Extract of Forsythia Suspensa (Thunb.) Vahl (Fruit) in Anti-Inflammatory and Analgesic Activities

Objectives The dried fruit of Forsythia suspensa (Thunb.) Vahl (FSTV) is a typical heat-clearing and detoxicating herb according to traditional Chinese medicine theory. This study was undertaken to evaluate the anti-inflammatory and analgesic activities of 85% ethanol extract of FSTV (FSTV-ET) in vivo. Methods Conventional reflux extraction method was used to prepare FSTV-ET with a yield of 42.7%. The analgesic activity of FSTV-ET was evaluated using the hot plate test and acetic acid-induced abdominal writhing test, and the anti-inflammatory activity was evaluated by the xylene-induced ear oedema model in female Kunming (KM) mice. Lipid peroxidation product malondialdehyde (MDA) and inflammatory mediator prostaglandin (PG) E2 were both detected using methods reported in the literature. Results FSTV-ET exerted analgesic activity with a significant dose-dependent increase in latency in the hot plate test. The percentage inhibition suggested that FSTV-ET exhibited analgesic activity in the central nervous system. Meanwhile, FSTV-ET at 0.16, 0.32, and 0.64 g/kg strongly inhibited the acetic acid-induced writhing response. FSTV-ET also exerted analgesic activity in the peripheral nervous system. Moreover, FSTV-ET demonstrated a significant anti-inflammatory effect against xylene-induced oedema in a dose-dependent manner, and reduced MDA and PGE2 levels. Conclusions These findings indicate that FSTV-ET can produce anti-inflammatory and analgesic activities in vivo, and the mechanism is likely to be related to inhibiting lipid peroxidation and inflammation. Acknowledgements Supported by project grants from the National Natural Science Foundation of China (Grant No. 81503269), the Funding Scheme for Young Key Teachers of Colleges and Universities in Henan Province (Grant No. 2014GGJS-072), and the Science and Technology Project of Zhengzhou (Grant No. 20150309).

Optimization of Microwave‐Assisted Extraction of Bioactive Compounds from Coriolus versicolor Mushroom Using Response Surface Methodology

AbstractResponse surface methodology was applied to optimize microwave‐assisted extraction (MAE) of total phenolic content (TPC) and antioxidant activity from fruiting bodies of Coriolus versicolor mushroom, and to compare its efficiency with conventional reflux extraction. A central composite design was employed for the optimization of three MAE parameters including extraction time (X1, min), ethanol concentration (X2, %) and microwave power (X3, W) for the highest yield of TPC and antioxidant activity measured by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2'‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) and ferric ion reducing antioxidant power (FRAP) assays in C. versicolor extracts. The optimum conditions were predicted as 3.8 min extraction time, 40% ethanol concentration and 125 W microwave power to obtain maximum values of TPC (470 mg GAE/100 g dm) and antioxidant activity measured by DPPH (773 µM TE/g dm), ABTS (2,930 µM TE/g dm) and FRAP (1,710 µM TE/g dm) assays, which were statistically verified by comparing with the experimentally observed values.Practical ApplicationsIn this study, microwave‐assisted extraction (MAE) showed significant potential as a green extraction method for obtaining Coriolus versicolor mushroom extract rich in polyphenols with higher antioxidant activity as compared to the extracts obtained by reflux extraction. Furthermore, MAE resulted in reduced consumption of energy, time and solvent with higher extraction yield and efficiency. This work demonstrated further feasibility studies on MAE of phytochemicals including polyphenols‐rich extracts at industrial scale. Moreover, successful application of response surface methodology has opened future research avenues for optimization of bioactive components from other mushrooms of medicinal importance.

Optimization of supercritical fluid extraction of bioactive components in Ligusticum chuanxiong by orthogonal array design

With the yields of ferulic acid, coniferylferulate, Z-ligustilide, senkyunolide A, butylidenephthalide, butylphthalide, senkyunolide I, senkyunolide H, riligustilide, levistolide A, and total pharmacologically active ingredient as evaluation indexes, the extraction of Ligusticum chuanxiong by supercritical fluid technology was investigated through an orthogonal experiment L9 (3(4)). Four factors, namely temperature, pressure, flow rate of carbon dioxide, co-solvent concentration of the supercritical fluid, were investigated and optimized. Under the optimized conditions, namely 65 degrees C of temperature, 35 MPa of pressure, 1 L x min(-1) of CO2 flow rate, 8% of co-solvent concetration, supercritical fluid extraction could achieve a better yield than the conventional reflux extraction using methanol. And the supercritical fluid extraction process was validated to be stable and reliable.

Optimization of ultrasound-assisted extraction (UAE) of flavonoids compounds (FC) from hawthorn seed (HS)

Hawthorn seed (HS), an important by-product of the Hawthorn industry, is rich in potentially health-promoting flavonoids compounds. In this paper, the ultrasound-assisted extraction (UAE) of FC from HS was investigated. Important variables and their levels were obtained using Plackett–Burman (PB) design and Box–Behnken (BB) design. A mathematical model was developed to show the effects of each variable and their combinatorial interactions on extraction yield of FC. A high coefficient of determination ( R 2 = 91.26%) indicated good agreement between the experimental and predicted values of FC yield. The optimum levels of these significant parameters were determined using response surface methodology (RSM), which revealed these as follows: ultrasound temperature 65 °C, ultrasonic time 37 min, extraction temperature 91 °C, extraction time 1.5 h, solid–liquid ratio of 1:18, and 72% ethanol. Under the optimum condition, the UAE rate of FC was up to 91.7%, and the yield of FC was 16.45 ± 0.02 mg/g ( P < 0.05) that was 1.32-fold the yield of conventional reflux extraction (CRE).

Effect of microwave irradiation on chemical profile of extracts during the extraction of organic compounds from Astragalus slices

The objective of this paper was to study the relationship between the chemical profile of extracts and the extraction behavior of plant porous materials using Astragalus water extraction as an example. The results will assist in the determination of optimal processing conditions and maintaining or improving the quality of natural products. Conventional reflux extraction (RE) and microwave-assisted extraction (MAE) were considered and compared. The molecular cutoff of ultrafiltration membranes was used to analyze the molecular weight distribution of extracts. Result shows that the yield of extracts by MAE (10 min) is significantly higher than that by RE (120 min), especially for those extracts with relative small molecular weight. Conventional hot air drying and microwave drying were also compared for further discussion on the effect of microwave irradiation on extracts. Atomic force micrograph (AFM) shows that the size of extracts (as particle height) are approximately 3.850–4.364, 6–10, and 100–300 nm for MAE-hot air drying, RE-microwave drying, and RE-hot air drying, respectively. Therefore, the results presented confirm that microwave irradiation can be used to prepare samples with uniform small size. This provides a better understanding of mass transfer behavior inside matrix during the extraction of plant materials. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.

Extraction of isoflavonoids from Pueraria by combining ultrasound with microwave vacuum

This study proposes a new method to quickly extract and dry isoflavonoids from Pueraria Lobata Ohwi (Pueraria) by combining ultrasound and microwave technologies. The time required to extract isoflavonoids at comparable levels of production by ultrasound disruption was 20 times shorter than by conventional reflux extraction. Moreover, test results for drying the extracted substance from Pueraria show that the microwave-vacuum method is 10 times faster than the conventional two-step vacuum approach. Finally, different instrumental analyses of isoflavonoids obtained from Pueraria using the proposed new method show that extraction by ultrasound disruption and microwave-vacuum drying affects neither the structure nor the composition of the extracted substance.

The optimization of microwave‐assisted extraction of decursin from Angelica gigas Nakai root

SummaryResponse surface methodology was used to display the characteristics of microwave‐assisted extraction (MAE) of soluble solids and decursin from Angelica gigas Nakai root, thereby allowing MAE conditions to be optimized. These included ethanol concentration, microwave power and extraction time. The maximal solid yield was predicted to be 44.2% under conditions of 44.9% ethanol concentration, 115.6 W microwave power and 5.8 min extraction time. Decursin content of the extract was estimated to be maximal at 2.52% using 97.7% ethanol, 90.2 W microwave power, and 6.1 min extraction time. The estimated optimal MAE conditions (67% ethanol, 100 W and 6 min) to maximize both components were verified by comparing estimated values with experimental values (42.2% soluble solids, 2.2% decursin), which were higher than those (35.8% solids, 2.0% decursin) obtained by conventional reflux extraction (60% ethanol, 95 °C and 6 h).

Microwave-assisted extraction of polysaccharides from solanum nigrum

The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the structures of polysaccharides were investigated. The extract was analyzed by the modified phenol-sulfuric acid method at 490 nm. The optimum experimental parameters were obtained by orthogonal experiments as follows: extraction time 15 min, microwave radiation power 455 W and the process ratio of materials mass to solvent volume 1:20. The results show that compared with the conventional reflux extraction, the microwave-assisted extraction has a higher yield in shorter time, with no effect on the finally obtained polysaccharides as seen from the FT-IR spectra. The scanning electron microscopy images reveal that the mechanism of the extraction is related to the structural changes of the plant cells in different extracting conditions.

Comparison of microwave and conventional extraction techniques for the determination of metals in soil, sediment and sludge samples by atomic spectrometry

A description is given of an extraction method for the determination of metals in sediment and soil samples using aqua regia[HCl—HNO3(3 + 1)] and a microwave oven. The elements Cd, Cr, Cu, Fe, Mn, Pb and Zn were measured in the solutions by means of atomic absorption spectrometry (flame or electrothermal) and inductively coupled plasma atomic emission spectrometry. The results for the analysis of six reference materials after microwave aqua regia extraction showed close agreement with the stated values. A comparison between microwave extraction and conventional reflux extraction for 30 samples showed that the former method gives the same or slightly higher results for the seven elements tested in sediments, soil and suspended matter.