The use of ultrasound in the extraction of Ilex paraguariensis leaves: a comparison with maceration

The objective of this work is to discuss the main parameters that influence the sonication extraction of Ilex paraguariensis leaves. For this purpose, the extraction time, solvent polarity, solvent volume, sample mass and particle size were evaluated. Results showed that the main variable affecting the extraction process was the solvent polarity. Though in a less extent, temperature and extraction time also demonstrated to be important parameters, while the other variables did not present a significant influence on the extraction yield. The extracts at the optimized condition were compared with those obtained by maceration, in terms of mass yield and chemical composition. The major compounds identified in the extracts were caffeine and palmitic acid. Some saturated hydrocarbons such as fatty acids, fatty acid methyl esters, phytosterols, and theobromine were also identified in the fractions.     

Kinetics of ultrasonic extraction of extractive substances from garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage

The kinetics of ultrasonic extraction of extractive substances (ES) from dry herbs of garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage using petroleum ether, 70% ethanol or water at 40 degrees C, as well as the composition of dry extracts, were studied. The mechanism of ultrasonic extraction is confirmed to occur in two steps: first, dissolution of the ES near the particle surface (washing) and, second, diffusion from the solid particles to the bulk of the liquid extract (slow extraction). The process is described mathematically using three concepts of the unsteady diffusion through plant material, the film theory and the empirical equation of Ponomaryov. The yield of ES increases with increasing solvent polarity, and nearly the maximum concentration of ES in liquid extracts is achieved for about 20 min. The composition of extracts depends on both the extraction conditions applied and the plant material.     

Comparisons between conventional,ultrasound-assisted and microwave-assisted methods for extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae)

This work reports a comparative study about extraction methods used to obtain anthraquinones (AQs) from stems and leaves of Heterophyllae pustulata Hook (Rubiáceae). One of the conventional procedures used to extract these metabolites from a vegetable matrix is by successive Soxhlet extractions with solvents of increasing polarity: starting with hexane to eliminate chlorophylls and fatty components, following by benzene and finally ethyl acetate. However, this technique shows a low extraction yield of total AQs, and consumes large quantities of solvent and time. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been investigated as alternative methods to extract these compounds, using the same sequence of solvents. It was found that UAE increases the extraction yield of total AQs and reduces the time and amount of solvent used. Nevertheless, the combination UAE with benzene, plus MAE with ethyl acetate at a constant power of 900 W showed the best results. A higher yield of total AQs was obtained in less time and using the same amount of solvent that UAE. The optimal conditions for this latter procedure were UAE with benzene at 50 °C during 60 min, followed by MAE at 900 W during 15 min using ethyl acetate as extraction solvent.     

Green extraction of lutein from marigold flower petals,process optimization and its potential to improve the oxidative stability of sunflower oil

Marigold flower petals are considered the richest source of lutein which possesses immense applications in the food and health sector. The study was undertaken to improve the stability of sunflower oil by enriching it with lutein extracted from marigold flower petals using safe and green technology. The extraction of lutein was optimized using Box-Behnken design by ultrasound-assisted extraction (UAE) employing sunflower oil as a solvent. The impact of three independent variables i.e., ultrasonic intensity, solid to solvent ratio, and extraction time were evaluated on the amount of lutein extracted and its antioxidant activity. Highest amount of lutein (21.23 mg/g) was extracted by employing ultrasonic intensity of 70 W/m2, extraction time of 12.5 min, and solid to solvent ratio of 15.75%. FT-IR spectra of lutein extracted by ultrasound and conventional extraction show similar peaks depicting that ultrasound does not have any impact on the functionality of lutein. Sunflower oil incorporated with lutein at 1000 PPM and the synthetic antioxidant (TBHQ) showed good oxidative stability than oil with 500 PPM lutein and no lutein during accelerated storage for a month. The oxidative stability was shown by different oil samples in the following order: TBHQ = 1000PPM lutein˃500PPM lutein ˃control oil. It was concluded that the ultrasound technique extracts lutein efficiently from marigold flowers and this lutein was effective in improving the oxidative stability of sunflower oil under accelerated storage conditions.     

超声辅助法提取白筋茎皮总黄酮的工艺研究

采用超声辅助法提取白霸茎皮中总黄酮化合物,通过单因素试验和正交试验,研究了超声提取条件（超声功率,乙醇浓度,料液比,时间）对其中总黄酮提取的影响。白筋茎皮总黄酮最佳提取工艺为：料液比1：30．乙醇浓度70％,超声功率120W,提取时间25min。在此工艺条件下提取,总黄酮含量为53．0843mg／g。     

水蒸汽蒸馏法及顶空-固相微萃取法提取青蒿花挥发性成分比较分析

采用水蒸汽蒸馏法(HD)及顶空固相微萃取法(HS-SPME)提取青蒿花的挥发性成分,GC-MS法分析其化学组成.已鉴定化合物占挥发性成分的95.01%(HD)和89.55%(HS-SPME).其中1.8-桉叶素(21.32%,20.96%),樟脑(24.34%,19.18%),莰烯(3.04%,5.26%),侧柏烯(3...     

Optimization of ultrasonic-assisted extraction of natural antioxidants from rice bran using response surface methodology

Ultrasonic technology was applied for extraction of polyphenols and antioxidants from the rice bran using ethanol as a food grade solvent. Response surface methodology (RSM) was used to optimize experimental conditions for extraction of polyphenols and antioxidants. Three independent variables such as solvent percentage (%), temperature (°C) and time (min) were studied. Effect of ethanol concentration was found to be significant on all responses. Total phenolic content (TPC) varied from 2.37 to 6.35mg gallic acid equivalent/g of dry sample. Antioxidant activity of the extracts was determined by the ferric reducing antioxidant power (FRAP) assay and scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. FRAP and DPPH values varied from 31.74 to 57.23μmol Fe(2+)/g of dry sample and 16.88% to 55.61% inhibition, respectively. Extraction yields ranged from 11 to 20.2%. Optimal ultrasonic-assisted extraction (UAE) conditions were identified as 65-67% ethanol, 51-54°C, 40-45min. The experimental values agreed with those predicted by SRM models, thus indicating suitability of the model employed and the success of RSM in optimizing the extraction conditions.     

土壤中无机砷测定的三种前处理方法比较

对土壤无机砷分析的样品前处理技术-微波辅助提取、超声波提取、水浴提取进行了对比研究.结合氢化物发生-原子荧光光谱(HG-AFS)测定技术比较了3种方法对国家土壤标准物质中无机砷的提取效果,并对溶剂类型、提取时间和提取剂用量等影响因素进行了考察.与超声波提取法和水浴提取法相比,微波辅助提取法具有快速、高效的优势.     

微波辅助萃取加拿大一枝黄花的花中总黄酮的工艺研究

对加拿大一枝黄花的花进行微波处理,考察微波辅助萃取对加拿大一枝黄花的花中总黄酮提取率的影响.以卢丁为标准品,用硝酸铝做显色剂,采用分光光度法在530nm波长处测定了加拿大一枝黄花的花中总黄酮的含量,探讨了料液比、乙醇浓度、微波功率、微波处理时间等因素对加拿大一枝黄花的花中总黄酮提取率的影响.结果表明,在料液比1:10、乙醇浓度70%、微波功率700W、微波处理时间15min最优条件下,加拿大一枝黄花的花中总黄酮的提取率为17.86%.     

Ultrasound-assisted extraction of anthraquinones from roots of Morinda citrifolia

This study investigated the use of ultrasound-assisted extraction (UAE) to improve the extraction efficiency of the classical solvent extraction techniques such as maceration and soxhlet extraction to extract anti-oxidant activity compounds, anthraquinones, from the root of Morinda citrifolia. The effects of different extraction conditions were determined, i.e., temperature of (25, 45, 60 °C), ultrasonic power, solvent types, and compositions of ethanol in ethanol–water mixtures. The results show that the yield increases with increasing extraction times and extraction temperatures. The percent recovery of anthraquinones using ultrasound was found to be highly dependent on the type of solvents (acetone > acetonitrile > methanol > ethanol). Furthermore, the use of ethanol–water solution as extraction solvent increased the yield of anthraquinones due to the relative polarity, the swelling effect of plant tissue matrix by water, and increased sound absorption. To achieve the same recovery as that achieved by UAE, soxhlet extraction and maceration required much longer time.     

Effect of oil extraction assisted by ultrasound on the physicochemical properties and fatty acid profile of pumpkin seed oil (Cucurbita pepo)

The effects of amplitude and time of ultrasound-assisted extraction on the physicochemical properties and the fatty acid profile of pumpkin seed oil (Cucurbita pepo) were evaluated. Ultrasound time (5–30 min) and the response variables amplitude (25–100%), extraction yield, efficiency, oxidative stability in terms of the free fatty acids (FFA) of the plant design comprising two independent experiments variables, peroxide (PV), p-anisidine (AV), totox value (TV) and the fatty acid profile were evaluated. The results were analyzed by multiple linear regression. The time and amplitude showed significant differences (P < 0.05) for all variables. The highest yield of extraction was achieved at 5 min and amplitude of 62.5% (62%). However, the optimal ultrasound-assisted extraction conditions were as follows: ultrasound time of 26.34 min and amplitude of 89.02%. All extracts showed low FFA (2.75–4.93% oleic acid), PV (1.67–4.68 meq/kg), AV (1.94–3.69) and TV (6.25–12.55) values. The main fatty acids in all the extracts were oleic and linoleic acid. Therefore, ultrasound-assisted oil extraction had increased performance and reduced extraction time without affecting the oil quality.     

Molecular diversity of volatile compounds in rare willow (<Emphasis Type="BoldItalic">Salix</Emphasis> spp.) honeydew honey: identification of chemical biomarkers

Salix spp. honeydew honey volatiles were analyzed for the first time by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) followed by gas chromatography and mass spectrometry (GC, GC-MS). The use of HS-SPME and USE had advantageous results over the use of one single technique, as it provided different complementary chromatographic profiles for a comprehensive screening of the honeydew volatile composition. The volatiles with different functionality, molecular weight, and polarity were extracted and identified. High percentages of benzoic acid, phenylacetic acid, 2-hydroxybenzoic acid, 4-hydroxyphenylacetic acid with minor percentages of 4-methoxybenzoic acid, 4-hydroxyphenylethanol, and 4-hydroxybenzoic acid from USE extracts can be emphasized as volatile biomarkers of this honeydew that probably originated from Salix spp., as well as methyl salicylate identified only by HS-SPME. The application of heat treatment at 80 °C for 2 h did not change significantly the volatile composition of this honeydew.     

Physicochemical and antioxidative properties of ultrasound-assisted extraction of mahua (Madhuca longifolia) seed oil in comparison with conventional Soxhlet and mechanical extractions

Ultrasound-assisted solvent extraction (UAE) was applied to extract underutilized Madhuca longifolia seed oil. The effect of extraction time, temperature, solvent type, solvent/sample ratio, and amplitude on the oil yield and recovery were investigated. Approximately 56.97% of oil yield and 99.54% of oil recovery were attained using mild conditions of 35 min, 35 °C, 40% amplitude, isopropanol to acetone (1:1), and solvent to sample (20 mL/g). UAE oil yield and recovery were comparable with Soxhlet extraction (SXE) whilst mechanical pressing (ME) yielded < 50% of UAE recovery. UAE does not affect the fatty acids composition (46% C18:1; 22% C16:0; 21% C18:0, 10% C18:2), and triacylglycerol profile (23% POO, 17% POS, 16% SOO, and 14% POP). Interestingly, UAE extracted oil conferred remarkably (P < 0.05) higher antioxidant capacity (IC₅₀ of DPPH 106.60 mg/mL and ABTS 39.80 mg/mL) than SXE (IC₅₀ of DPPH 810.40 mg/mL and ABTS 757.43 mg/mL) or ME (IC₅₀ of DPPH 622.38 mg/mL and ABTS 392.87 mg/mL).     

鱼腥草中总黄酮的微波辅助萃取研究

对鱼腥草进行微波处理,考察微波对鱼腥草中总黄酮提取的影响.以鱼腥草中总黄酮的提取量为指标,考察微波功率、微波作用时间、溶剂用量、鱼腥草粒度、水浸泡时间等因素的影响.鱼腥草中总黄酮提取的最佳工艺条件:鱼腥草用微波功率640W、间歇作用时间5min、固液比1∶40、粒度为细粉、浸泡时间为60min.     

信阳红、绿茶提取物的抗氧化能力

以信阳红、绿茶为原料,水和95％的乙醇为提取溶剂,考察提取物对羟自由基（·OH）和超氧阴离子自由基（·O2-）的清除作用.结果显示,两种溶剂红、绿茶提取物对两种自由基均有显著地清除作用,且红、绿茶水提取物对两种自由基的清除能力均高于乙醇提取物,两种溶剂红茶提取物对羟自由基（·OH）清除能力大于绿茶,绿茶乙醇提取物对超氧阴离子自由基（·O2-）清除能力大于红茶.     

Ultrasound-assisted deep eutectic solvents extraction of glabridin and isoliquiritigenin from Glycyrrhiza glabra: Optimization,extraction mechanism and in vitro bioactivities

Licorice (Glycyrrhiza glabra) is extensively used owing to the superior pharmacological effects. However, its maximum application potential has not been fully exploited due to the limitation of currently available extraction solvent and methods. In this study, an eco-friendly deep eutectic solvent (NADESs) based ultrasound-assisted extraction (DES-UAE) method was applied to prepare licorice extracts. The DES-UAE using choline chloride and lactic acid as solvent was optimized and modeled by using response surface methodology to maximize the extraction yields of glabridin (GLA) and isoliquiritigenin (ISL). The optimized extracts possessed higher contents of GLA and ISL than available extraction methods, and the enriched products showed superior pharmacological activities in vitro. Furthermore, scanning electron microscopy (SEM) and molecular dynamic simulation analyses were performed to deeply investigate the interaction between solvent and targeted compounds. This study not only provides an eco-friendly method for high-efficient extraction of GLA and ISL from licorice but also illustrates the mechanism of the increased extraction efficacy, which may contribute to the application of licorice and deep insight into extraction mechanism using DES.     

Ultrasound-assisted preparation of ‘Ready-to-use’ extracts from Radix Paeoniae Rubra with natural deep eutectic solvents and neuroprotectivity evaluation of the extracts against cerebral ischemic/ reperfusion injury

Natural deep eutectic solvent (NaDES) is widely applied in the extraction of nutrients from natural resources as a greener alternative for fossil solvent. In the present work, 27 different NaDESs were screened for the extraction of paeoniflorin (PF) and galloyl paeoniflorin (GPF) from Radix Paeoniae Rubra (RPR). After screening and extraction parameter optimization, the extraction yields of PF and GPF reached up to 182.8 mg/g and 77.4 mg/g with the selected NaDES, ChCl-Sor. Furthermore, the antioxidant activity in vitro and neuroprotectivity in vivo of the ‘ready-to-use’ extracts were evaluated comprehensively. Especially in vivo, the cerebral ischemic/ reperfusion injury model was established in rats and the protective effects of the RPR extracts were determined. The results not only proved that NaDES is a valuable green extraction media, but also indicated the safety and potential pharmaceutical application of NaDES based ‘ready-to-use’ extracts from medical plants.     

Comparison of classical and ultrasound-assisted extractions of steroids and triterpenoids from three Chresta spp

A comparative study of classical and ultrasound-assisted extractions of steroids and triterpenoids from stem, leaves and flowers of Chresta exsucca, C. scapigera and C. sphaerocephala is described. The direct analysis of crude apolar and medium-polar extracts has been conducted by high-resolution gas chromatography followed by co-injections of the crude extract with certified standards on capillary columns of different polarities. The use of ultrasound decreased significantly the total time of treatment and in addition, this extraction method was more effective for the steroids and most of the triterpenes.     

Stability of thiosulfinates from garlic (<Emphasis Type="Italic">Allium sativum</Emphasis> L.) supercritical extracts in polar and nonpolar solvents

For the first time a systematic investigation of the decomposition process of allicin and other thiosulfinates from garlic supercritical extracts (SCEs) in solvents of different polarity (water, ethanol, acetonitrile, dimethyl sulfoxide, dichloromethane, and hexane) was performed. Qualitative and quantitative analysis of the garlic thiosulfinate decomposition products was carried out. A new HPLC analytical procedure was developed; it allows simultaneous determination of both starting thiosulfinates and sulfur-containing products of their decomposition. It was shown that the decomposition of SCE thiosulfinates can be directed toward the formation of target substances (ajoenes, dithiins, trisulfides, etc.) by changing the solvent polarity. The results obtained and methodical developments can be used in biomedical research of garlic-based drugs, as well as in the processes of their preparation, storage, and analysis.     

不同极性溶液中MEH-PPV链内激子扩散的研究

本文采用飞秒时间分辨瞬态光栅技术研究了MEH-PPV在不同极性溶液中的内激子扩散行为. 采用宽带连续白光同时探测瞬态吸收和瞬态光栅信息. 系统地研究了MEH-PPV的振动失相行为以及单激子弛豫和粒子数弛豫动力学. 结果表明,在极性较大的溶剂中,样品溶液的弛豫扩散过程会加快.