Pressurized Microwave-assisted Extraction Research Articles

Extraction and purification of total flavonoids from Gnaphalium affine D. Don and their evaluation for free radicals’ scavenging and oxidative damage inhabitation potential in mice liver

The parameters for pressurized microwave-assisted extraction (PMAE) of total flavonoids (TFs) from Gnaphalium affine D. Don were investigated and the effect of PMAE on its cell wall and tissue structure was analyzed via scanning electron microscopy (SEM). Afterwards, its extraction effect was compared with that of microwave-assisted extraction (MAE), soxhlet extraction (SE) and heat reflux extraction (HRE). After purifying by AB-8 macroporous resin, the in vitro and in vivo antioxidant activities of purified TFs were evaluated by five different chemical assays and alcohol-induced model, respectively. Our findings revealed that an ethanol volume fraction of 81.3%, a L/S ratio of 25.4 mL/g and an extraction time of 138 s, give maximum yield of TFs (1.35 ± 0.02%). PMAE was more efficient and rapid in extracting TFs from G. affine because it cracked the cell wall and disrupted the tissue structure, as observed by SEM. Compared with microwave-assisted extraction (MAE), soxhlet extraction (SE) and heat reflux extraction (HRE), PMAE was more efficient and rapid technique for the extraction of TFs from G. affine. TFs from G. affine showed notable free radical, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt (ABTS) cation, scavenging abilities and reduction ability in vitro. It could also significantly reduce the level of malondialdehyde (MDA), enhance the activity of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC), and increase the level of glutathione (GSH) in the liver of mice with oxidative damage in a dose-dependent manner. Therefore, it showed good antioxidant capacity in vivo. TFs from G. affine indicated good in vitro and in vivo antioxidant activities, which suggests their potential in functional foods and pharmaceuticals as natural antioxidants agents.

The Scenario of Pharmaceuticals and Development of Microwave Assisted Extraction Techniques

Microwave-assisted extraction (MAE) or simply microwave extraction is a relatively new extraction technique that combines microwave and traditional solvent extraction. Application of microwaves for heating the solvents and plant tissues in extraction process, which increases the kinetic of extraction, is called microwave-assisted extraction. The use of MAE in natural products extraction started in the late 1980, though the technological developments, it has now become one of the popular and cost-effective extraction methods available today, and several advanced MAE instrumentations and methodologies have become available, e.g., pressurized microwave-assisted extraction (PMAE) and solvent-free microwave-assisted extraction (SFMAE). This chapter provides an overview of the MAE and presents a number of specific proto collateral products extraction.

Determination of different arsenic species in food-grade spirulina powder by ion chromatography combined with inductively coupled plasma mass spectrometry.

A "two-step" pressurized microwave-assisted extraction method coupled with ion chromatography with inductively coupled plasma mass spectrometry for the determination of different arsenic species in spirulina samples was developed. The extraction method used H2 O2 /H2 O (1:5, v/v) as solvent to extract all arsenic species except arsenite, which was extracted by using water as solvent. The extraction method had a satisfactory recovery (>96%) and took a short time (20.0min). With our method, all arsenic species in spirulina samples were completely separated and determined with recoveries of 84-105% and relative standard deviations of 2-4%. Food-grade spirulina powder samples from seven provinces (Inner Mongolia, Zhejiang, Fujian, Hainan, Yunnan, Jiangsu, and Guangxi) in China were analyzed using the optimized protocol. Arsenate was detected at the concentration range of 170-394ng/g in all the spirulina samples. Dimethylarsinic acid was detected at the concentration range of 32-839ng/g in spirulina from above-six provinces except Guangxi. Monomethylarsonic acid (67±3ng/g) was detected only in spirulina from Yunnan province. Arsenite was detected at the concentration range of 28-147ng/g in spirulina from above five provinces except Hainan and Guangxi. Five unknown organic arsenic species were found in spirulina from above six provinces except Guangxi.

Extraction of phytocompounds from the medicinal plant Clinacanthus nutans Lindau by microwave-assisted extraction and supercritical carbon dioxide extraction

The composition and bioactivity of natural plant extracts strongly depends on the extraction technique employed. Clinacanthus nutans Lindau (C. nutans) is a well-known medicinal plant in South-East Asia that has been traditionally used for treatment of hepatitis, skin-rashes and snake venom poisoning, and recently has attracted attention for its applications for treatment and prevention of cancer diseases. In previous studies, the extraction of bioactive compounds from C. nutans by conventional Soxhlet solvent extraction has been described, but this method shows limitations in terms of selectivity, extraction yield and toxicity of the solvents employed. In this study, phytochemical compounds were extracted from leaves and stems of C. nutans by microwave-assisted extraction (MAE), pressurized microwave-assisted extraction (PMAE), supercritical carbon dioxide extraction (SFE) and Soxhlet method to investigate the best technique in terms of yield, extraction time and recovery of bioactive compounds: phenols, flavonoids, phytosterols and β-sitosterol. The extracted phytocompounds and phenolics were characterized by gas chromatography mass spectrometry (GC/MS) and ultra performance liquid chromatography (UPLC). The results showed that MAE was the best technique to achieve a high yield and a maximal total polyphenol content (11.30±0.39mg GAE/g DM) and flavonoids content (and 4.66±0.20mg GAE/g DM), whereas SFE was the best method for phytosterols and β-Sitosterol extraction. P-MAE merely enhanced the polyphenol and flavonoids yield to 14.56±0.77mgGAE/g DM and 5.29±0.30mg QE/g DM respectively, without significant variations on the type of compounds obtained. MAE appears as the most efficient technique for the extraction of phytochemical compounds from C. nutans in a short time with a reasonable yield and a good selectivity toward bioactive nutraceutical compounds, with high concentrations of antioxidants, anti-inflammatory and antimicrobial compounds.

Development of a one-step microwave-assisted subcritical water extraction for simultaneous determination of inorganic elements (Ba, Ca, Cu, Fe, Mg, Mn, Na, Pb, Sr, Zn) in reference materials by microwave induced plasma spectrometry

A “green” procedure has been developed for the simultaneous extraction of total inorganic elements (Ba, Ca, Cu, Fe, Mg, Mn, Na, Pb, Sr, Zn) in certified reference materials by using pressurized subcritical water extraction. Samples (0.1g) were subjected to 10min pressurized microwave-assisted extraction with water modified with 1% (v/v) HNO3 at 280°C and 90bar. A Univariate approach and the Simplex optimization procedure were used to achieve optimized conditions and derive analytical figures of merit. The target elements have been simultaneously determined by microwave induced plasma-optical emission spectrometry (MIP-OES). The experimental concentration detection limits for simultaneous determination, calculated as the concentration giving a signal equal to three times of the standard deviation of the blank (LOD, 3σblank criterion, peak height) were in the range of 2.5 to 11ngmL−1. The method offers relatively good precision (RSD ranged from 5 to 7%) for liquid samples. Method validation was performed analyzing two certified reference materials (IAEA-336 Trace and Minor Elements in Lichen and CRM No. 12-2-02 Essential and Toxic Elements in Green Algae P-ACHK) and by the aqueous standard calibration technique. The measured contents of elements in reference materials were in satisfactory agreement with the certified values.

Pressurized Microwave-Assisted Extraction of Total Isoflavones from Pueraria Lobata

The single factor experiment method was used to investigate the effects of microwave power（P）, extraction pressure(p), alcohol mass concentration（x%）, ratio of liquid to solid (l/s), pre-immersed time(τ) and particle size(d) on extraction efficiency of total isoflavones from pueraria lobata by pressurized microwave-assisted extraction technique. Based on the above the Design-Expert 6.0 software was used to carry out a response surface test with three factors (ratio of liquid to solid, pressure and alcohol mass concentration) to optimize the technical conditions and establish the mathematical model. The results show that the optimum technical conditions are: P =700w, p =132.61kPa, x =51.2%, l / s =10.45,τ=2h，d = 80 meshes. Under these conditions the extraction efficiency reaches 98.75% which is 23.5% higher than that by microwave-assisted extraction at atmospheric pressure. The established model (second multivariate regression equation) is consistent with the experiment and can predict the extraction efficiency of the total isoflavones under different technical conditions.

Determination of Seven Major Ginsenosides in Different Parts of Panax quinquefolius L.(American Ginseng) with Different Ages

Ginsenosides Rg1, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction(PMAE). The seven ginsenosides were separated and determined by high-performance liquid chromatography(HPLC) with a ultraviolet(UV) detector, at 203 nm. The experiment results showed significant variations in the individual ginsenoside contents of the American ginseng in different parts and ages of the plant. The results demonstrated that the leaves, root hairs, and rhizomes of Panax quinquefolius L. contained higher ginsenoside contents, followed by the main roots and stems. The leaves contained dramatically higher levels of ginsenoside Rg1, Rb3, and Rd than the other four parts. Higher contents of Rb1 and Re were present in the main roots, root hairs, and rhizomes. The amount of ginsenoside content in the stems was the lowest. The total content of the seven ginsenosides in main roots, root hairs and rhizomes increased with the age of the plant. In contrast, the ginsenoside contents in the leaves and stems decreased with a year of growth.

Determination of triazines in infant nutrient cereal-based foods by pressurized microwave-assisted extraction coupled with high-performance liquid chromatography–mass spectrometry

A method for determining triazine herbicides in infant nutrient cereal-based foods by pressurized microwave-assisted extraction (PMAE), coupled with high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC–ESI/MS), is described. The key parameters of PMAE, including extraction solvent, extraction time and temperature, were optimized. The isolation of the target compounds from the matrix was found to be efficient when 2 g of nutrient cereal samples was extracted with 20 mL of methanol for 10 min at 105 °C. Final determination was accomplished by HPLC–ESI/MS. The recoveries from 66.2 to 88.6% were obtained for three compounds at fortification levels (5–500 μg kg −1) with relative standard deviations (R.S.D.) ≤12.62%. Compared with atmospheric pressure microwave-assisted extraction (AMAE), ultrasonic extraction (UE) and soxhlet extraction (SE), the proposed method was more efficient, faster and more straightforward and required no additional cleanup steps. When the proposed method was applied to the aged spiked nutrient cereal samples, the results indicated that, although the recoveries of analytes were much lower than those obtained from fresh spiked samples, they were nevertheless satisfactory for the quantitative analysis of practical samples.

Dynamic microwave-assisted extraction of flavonoids from Herba Epimedii

An apparatus for extraction of flavonoids from Herba Epimedii has been constructed which utilizes a microwave technique for heating in a dynamic mode. A TM 010 microwave resonance cavity was applied to concentrate the microwave energy; the power needed to achieve efficient extraction was significantly reduced. The method has been compared with other extraction methods, such as pressurized microwave-assisted extraction (PMAE), ultrasonic extraction (UE), heat reflux extraction (RE) and Soxhlet extraction (SOX). The four flavonoids in extract were identified by HPLC–MS. The influence of extraction parameters on the extraction yield of flavonoids has been evaluated by comparison with the peak areas of HPLC-DAD spectra in the different extraction methods. The results showed that the extraction yield of flavonoids in Herba Epimedii obtained by dynamic microwave-assisted extraction (DMAE) was higher than that obtained by UE, RE and SOX, and the extraction time is dramatically reduced. The extraction yield obtained by DMAE is similar to that obtained by PMAE. But the flavonoids in Herba Epimedii would not decompose easily when increasing the extraction time in DMAE. This is the benefit of dynamic extraction system which can transfer the analytes extracted from the sample matrix with flowed fresh solvent to the out of extraction vessel.

Dynamic Microwave-assisted Extraction of Flavonoids from Radix Scutellariae

Dynamic microwave-assisted extraction (DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the flavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction (PMAE), ultrasonic extraction (UE), soxhlet extraction (SE), and reflux extraction (RE), and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellarie.

Comparison of the Different Extraction Methods of Flavonoids in Epimedium Koreamum Nakai by HPLC‐DAD‐ESI‐MSn

In the present paper, the flavonoids in Epimedium Koreamum Nakai have been extracted by atmospheric pressure microwave assisted extraction (AMAE), pressurized microwave assisted extraction (PMAE), ultrasonic extraction (UE), and reflux extraction (RE), and the extracts have analyzed by HPLC‐DAD‐ESI‐MSn. As a result, the four flavonoids in the extracts have been identified as epimedin A, epimedin B, epimedin C, and icariin. Also, the influence of extraction parameters on the extraction yields of epimedin A, epimedin B, epimedin C, and icariin has been evaluated by comparison with the peak areas of HPLC‐DAD spectra in the different extraction methods. The experimental results demonstrate that the advantage of PMAE and AMAE over conventional RE is validated, the extraction time is dramatically reduced, and the yields of flavonoids are effective improved. Although the UE method can be carried out within a short time, the extraction yields of flavonoids are lower compared with other extraction methods.