Microwave-assisted extraction and content determination of astilbin in Lysiphyllum strychnifolium stems

Abstract Lysiphyllum strychnifolium (Craib) A. Schmitz. (in Thai name, Ya nang daeng) has been traditionally used to treat fever, alcohol intoxication, cancer, allergies, and blood toxins. It can be used as a health-promoting herbal tea and contains hydroalcoholic extracts. The purpose of the present study was to develop a microwave-assisted extraction method for astilbin in L. strychnifolium stems. HPLC was used to determine astilbin content. Three extraction conditions were optimized: types of solvent, microwave power levels, and the number of extraction cycles. Water:methanol (40:60) was the best solvent for astilbin extraction from L. strychnifolium stems using 450 watts and six microwave-assisted extraction cycles. This technique offers important advantages over conventional methods, such as shorter extraction times, substantial energy savings, and a reduced environmental burden.

Extracción por microondas libre de solvente del aceite esencial de naranja (Citrus sinensis), y el efecto de las condiciones de proceso en su rendimiento, composición y actividad antimicrobiana

RESUMEN La extracción asistida por microondas (MAE por sus siglas en inglés) es una técnica eco amigable relativamente nueva que ha recibido una atención creciente debido a su menor tiempo de extracción y consumo de energía, mayor rendimiento de compuestos de interés y menor consumo de disolvente; a diferencia de técnicas convencionales de extracción, que implican elevados gastos de energía y tiempo. Así mismo, subproductos de industrias como cáscaras de cítricos, son desechados en grandes cantidades, no aprovechándose las propiedades funcionales sus compuestos. En esta investigación se realizó la extracción de aceite esencial a partir de cáscara de naranja, por microondas libre de solventes (SFME por sus siglas en inglés), a diferentes condiciones de potencia (400, 800 W, y sus combinaciones). El objetivo fue evaluar el efecto de las diferentes condiciones de proceso sobre el rendimiento del aceite esencial extraído, sobre su composición química y actividad antimicrobiana. Los más altos rendimientos de extracción correspondieron a los aceites extraídos a 400 W y a 800/400 W, siendo este último el que conllevó un menor gasto de energía y emisión de CO2. En general, todos los aceites extraídos presentaron los mismos compuestos mayoritarios (limoneno, β- mirceno, linalool y α- pineno), mientras que el aceite sometido a 400 W, presentó cantidades menores de 0,23% de 5 compuestos minoritarios adicionales. Sobre la actividad antimicrobiana, se detectó mayor actividad contra Listeria monocytogenes (ATCC 19115) respecto a Escherichia coli (ATCC 8739) en todos los tratamientos.

ABSTRACT Microwave assisted extraction (MAE) is a relatively new ecofriendly technique that has received increasing attention due to its reduced extraction time and energy consumption, higher yield and lower solvent consumption; unlike conventional extraction techniques, which involve higher energy costs and greater time. Likewise, industry by-products such as citrus peels are disposed of in large quantities, thus functional properties of their compounds are left unused. In the present investigation, solvent-free microwave extraction (SFME) was used to obtain orange peel essential oil at different power conditions (400, 800 W, and their combinations). The aim was to evaluate the effect of the process on the yield, composition and antimicrobial activity of the essential oil obtained. The highest extraction yields were obtained using powers of 400 and 800/400 W, corresponding the minor energy and CO2 emission generated to the latter. In general, all oils had the same major components (limonene, β- myrcene, linalool and α- pinene), with the oil obtained at 400 W having, in addition, five minor compounds, in amounts less than 0.23%. Regarding antimicrobial activity, in general, greater activity against L. monocytogenes (ATCC 19115) was detected in comparison with E. coli (ATCC 8739) in all treatments.

Design of ionic liquid-based microwave-assisted extraction of flavonoids from Cyclea barbata Miers. and its lipoxygenase inhibitory activity

Green grass jelly (Cyclea barbata Miers.) is a plant from Indonesia that is believed to have anti-inflammatory activity.This study aims to find the optimum condition in grass jelly extraction using the ionic liquid-microwave assistedextraction toward total flavonoid content (TFC) and lipoxygenase activity (LIA). The experimental design wasperformed using the parameters variable including extraction time, liquid–solid ratio, and ionic liquids concentrationto obtain the optimum condition. The optimization analysis used response surface methodology (RSM) with Box–Behnken design (17 trials) to obtain a predictive model with TFC and LIA as a response surface value. In the presentstudy, the optimum condition was suggested by RSM analysis with parameter variables, including extraction time of17 minutes, 1-butyl-3-methylimidazolium bromide ([BMIM]Br) concentration of 1.76 mol/l, and the liquid–solid ratioof 38.21 ml/g. The equation of regression quadratic model was obtained to predict TFC and LIA as follows: TFC =2.43A + 2.43B + 1.42C + 0.33AB − 3.20AC − 0.46BC − 4.90A2 − 3.10B2 − 3.10C2 + 28.32 with R2 = 0.8336 and LIA= 0.066A + 8.22B + 0.97C + 2.47AB − 5.86AC + 1.96BC − 9.99A2 − 13.75B2 − 13.11C2 + 63.53 with R2 = 0.9207,respectively

Application of Tween 80 and Tween 20 for microwave-assisted extraction of oxyresveratrol from mulberry (Morus alba L.) twigs

Oxyresveratrol is a polyphenolic compound found in Mulberry (Morus alba L.) twigs and has known as a skinlightening agent. Many methods can be applied to extract oxyresveratrol from Mulberry twigs. This researchaimed to optimize the extraction method by using surfactant Tween 80 and Tween 20-based microwave-assistedextraction (MAE). Extraction parameters, including solvent concentration, liquid–solid ratio, and extraction time foroxyresveratrol, were optimized using response surface methodology based on Box–Behnken Design. This researchalso extracted the oxyresveratrol by maceration, and then the oxyresveratrol content from each extraction methodwas compared. Oxyresveratrol content was determined using high-performance liquid chromatography (HPLC). ForTween 80, the optimum condition was obtained at 10.5 mM, 30:1 ml/g liquid–solid ratio, and 10 minutes extractiontime. For Tween 20, the optimum condition was obtained at 100 mM, 40:1 ml/g liquid–solid ratio, and 5 minutesextraction time. Oxyresveratrol content was 0.0146 mg/g dried sample and 0.0172 mg/g dried sample at the optimumcondition of Tween 80 and Tween 20 surfactant, respectively. Meanwhile, the oxyresveratrol content of the macerationmethod with 96% ethanol was 1.5704 mg/g dried sample. In conclusion, these results show that the application ofTween 80 and Tween 20 as solvents for MAE of Oxyresveratrol from mulberry twigs was not fully successful sinceother extraction conditions should be considered, such as temperature, pH, and microwave energy.

Optimization of microwave-assisted extraction technique for isolation of betulinic acid from Dillenia indica Linn. and its quantification using developed HPTLC method

Modern extraction technique was investigated for the separation of betulinic acid from the bark of Dillenia indicaLinn. Betulinic acid, a pentacyclic triterpenoid, is a potent anticancer compound and possesses other pharmacologicalactions. The objective of the present study was to investigate the optimum extraction conditions for betulinic acidusing microwave-assisted extraction by applying response surface methodology based on three factors three levelsBox–Behnken experimental design. The extraction was performed by considering three different independent variables:extraction temperature (70°C–90°C), microwave power (100 W), and extraction time (10–20 minutes) and quantifiedusing developed High-performance thin layer chromatography method. The maximum yield of betulinic acid at optimizedexperimental conditions, i.e., 90°C, 200 W, 15 minutes was found to be 0.91%w/w. Analysis of variance showed that the“p-value” was 0.0004 which indicate that the models were statistically significant (p ˂ 0.05). The value of the “coefficientof determination” (R2) for microwave-assisted extraction was 0.94 which indicate that the model shows the goodness offit. To conclude, Microwave Extraction technique along with response surface design proved to be efficient compared toconventional methods which could be applied to isolate active constituents from plant sources.

Applications of new methods in extraction of flavonoids from Chinese materia medica / 中草药

Flavonoids are widely found in medicinal plants, which have important medical properties. Flavonoids were proved to have many pharmacological activities, such as anti-oxidation, antitumor, antimutation, anti-inflammatory, antibacterial and anti-aging. The extraction of flavonoids is the crucial link in their clinical applications. In recent years, many emerging Chinese medicine extraction methods have also been widely used in the extraction of flavonoids. This paper reviews the current application of new methods for flavonoid extraction, in order to provide references for the extraction, development and utilization of flavonoids. These new extraction methods include supercritical fluid extraction (SFE), ultrasonic assisted extraction (UAE), microwave assisted extraction (MAE), pressurized liquid extraction (PLE), pulsed electric field (PEF) assisted extraction, enzyme assisted extraction (EAE), green solvent extraction, steam explosion assisted extraction, dynamic high pressure microfluidization (DHPM) assisted extraction, etc.

Microwave Assisted Extraction, Optimization using Central Composite Design, Quantitative Estimation of Arjunic Acid and Arjunolic Acid using HPTLC and Evaluation of Radical Scavenging Potential of Stem Bark of Terminalia arjuna

The optimization and microwave assisted extraction of stem bark of Terminalia arjuna, quantitative estimation of the marker compounds arjunic acid and arjunolic acid using HPTLC and the evaluation of free radical scavenging activity has been performed in this study. The central composite design was used for optimization and the values of parameters for optimized batch of microwave assisted extraction were 1000W (Power), 3 minutes (Time) and 1/120 (Solid/solvent ratio). The solvent system to carry out the HPTLC was toluene: acetic acid: ethyl acetate (5: 5: 0.5) and quantitative estimation was done using standard equations obtained from the marker compounds. The in-vitro free radical scavenging activity was performed spectrophotometrically using ascorbic acid as standard. The value of estimated percentage yield of arjunic acid and arjunolic acid was 1.42% and 1.52% which upon experimentation was obtained as 1.38% and 1.51% respectively. The DPPH assay of the different batches of microwave assisted extraction and marker compounds taken suggested that the marker compounds arjunic acid and the arjunolic acid were responsible for the free radical scavenging activity as the batch having the maximum percentage yield of the marker compounds showed best free radical scavenging effect as compared to standard ascorbic acid. The IC₅₀ value of the optimized batch was found to be 24.72 while that of the standard ascorbic acid was 29.83. Hence, the yield of arjunic acid and arjunolic acid has direct correlation with the free radical scavenging activity of stem bark extract of Terminalia arjuna and have potential to serve as active lead compounds for free radical scavenging activity.

Estudio de la capacidad antioxidante in vitro de Phaseolus vulgaris L. (frijol) mediante extracción asistida por microondas / Study of in vitro antioxidant capacity of Phaseolus vulgaris L. (frijol) by microwave assisted extraction

Introducción: Phaseolus vulgaris L. (frijol) es una fuente nutricional importante en Colombia, que aporta un gran contenido de sustancias bioactivas con potencial benéfico para la salud, tales como polifenoles, entre otras, que contribuyen de manera sinérgica con sus propiedades terapéuticas, y que pueden tener un efecto positivo contra algunas patologías. Objetivos: evaluar el método de extracción asistido por microondas como método alternativo para estudiar la capacidad antioxidante in vitro en ocho variedades de P. vulgaris L. cultivadas en Colombia. Métodos: semillas sin piel de P. vulgaris, deshidratadas y maceradas se sometieron a extracción asistida por microondas y extracción sólido-líquido; el contenido de fenoles se evaluó por el método de Folin-Ciocalteu y el potencial antioxidante in vitro se evaluó con base en los métodos del radical estable catión radical difenil-picrilhidrazilo y el radical catión 2,2´-azino-bis(ácido 3-etilbenzotiazolin-6-sulfunico). Resultados: el método de extracción asistido por microondas realizada en horno microondas convencional fue más eficiente respecto a la convencional ya que disminuyó la cantidad de solvente, de muestra empleada y los tiempos de extracción. Los extractos obtenidos por extracción asistida por microondas en horno microndas convencional presentaron un contenido de fenoles entre 29,36 y 60,61 g EAG/L, mientras que el método extracción sólido-líquido, estuvo entre 32,75 y 113,27 g EAG/L. El efecto anti-radicalario fue similar entre los extractos evaluados. Conclusiones: todos los extractos presentaron buena capacidad protectora contra radicales libres, y la técnica de extracción asistida por microondas en horno microndas convencional puede ser usada como método alterno para una valoración rápida, eficiente y eficaz del contenido de sustancias bioactivas en diferentes matrices, se presentó mínimas diferencias entre los resultados obtenidos, comparados con las metodologías de extracción asistida por microondas establecidas antes(AU)

Introduction: Phaseolus vulgaris L. is a representative crop of nutrient and economic importance in Colombia. Additionally, P. vulgaris is considered as a natural source of bioactives compounds, such as polyphenols, which have been associated with valuable effects on health. Objetives: to evaluate the microwave extraction assisted technique as an alternative methodology to study the antioxidant capacity of eight varieties of P. vulgaris cultivated in Colombia. Methods: dehydrated and powered seeds of P. vulgaris was subjected to microwave assisted extraction and solid-liquid extraction and. Total phenolis content was determined by Folin-Cicoulteau method and the potential antioxidant was evaluated using diphenyl-picrylhydrazyl radical stable and 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation assays. Results: microwave assisted extraction-Household microwave oven technique was more efficient and versatile than SLE method. The extracts obtained microwave assisted extraction-Household microwave oven methodology showed polyphenol content ranged between entre 29,36 and 60,61 g EGA/L, but SLE was over 32,75 and 113,27 g EAG/L. Conclusions: all extracts showed a considerable antioxidant potential against free radical, and microwave assisted extraction-Household microwave oven method could be used as an alternative method for fast, efficient and effective evaluation of the content of polyphenol in various matrices, with minimal differences comparing to established microwave assisted extraction techniques(AU)

Validación de una metodología analítica para la cuantificación de polifenoles totales, en procesos de extracción asistida por microondas sobre frutos de la especie colombiana Vaccinium meridionale / Validation of an analytical method for quantification of total polyphenols in microwave-assisted extraction processes for the Colombian species Vaccinium meridionale

En este trabajo se muestra el desarrollo y la validación de un método analítico para la cuantificación de polifenoles totales con el reactivo de Folin-Ciocalteu (F-C),en procesos de extracción asistida por microondas (MAE), sobre frutos de la especie colombiana Vaccinium meridionale. Los resultados obtenidos en los parámetros selectividad, linealidad, repetibilidad y exactitud muestran que la metodología propuesta es confiable para evaluar el efecto de las condiciones de extracción sobre la cantidad de polifenoles removidos.

In this work, we show the development and validation of an analytical method for quantification of total polyphenols with Folin-Ciocalteu reagent (F-C) in microwave-assisted extraction processes for Colombian species Vaccinium meridionale. Experimental results of selectivity, linearity, repeatability and accuracy evidence that the methodology proposed is reliable to evaluate the effect of the extraction conditions over the quantity of polyphenols removed.

Optimization of microwave-assisted extraction of bioactive alkaloids from lotus plumule using response surface methodology☆ / 药物分析学报

In this work, a fast and efficient microwave-assisted extraction (MAE) method was developed to extract main bioactive alkaloids from lotus plumue. To optimize MAE conditions, three main factors were selected using univariate approach experiments, and then central composite design (CCD). The optimal extraction conditions were as follows: methanol concentration of 65%, microwave power of 200 W, and extraction time of 260 s. A high performance liquid chromatography–diode array detector (HPLC–DAD) method was established to quantitatively analyze these phytochemicals in different lotus plumule samples and in different part of lotus. Chromatographic separation was carried out on an Agilent Zorbax Extend-C18 column (4.6 mm×150 mm, 3.5 μm). Gradient elution was applied with the mobile phase constituted with 0.1%triethylamine in water (A) and acetonitrile (B): 40%?70% B at 0?8 min, 70%?100% B at 8–9 min, 100% B for 2 min, and then equilibrated with 40%B for 2 min.

Effect of certain natural products and organic solvents on quorum sensing in Chromobacterium violaceum

OBJECTIVE@#To investigate the effect of seed extracts of Pongamia pinnata, Pyrus pyrifolia, and Manilkara hexandra, bacterial pigment prodigiosin, and three organic solvents (ethanol, methanol, and dimethylsulfoxide), on quorum sensing (QS) in Chromobacterium violaceum (C. violaceum).@*METHODS@#C. violaceum was challenged with plant extracts prepared by microwave assisted extraction method, prodigiosin, and organic solvents. Effect of these test substances on C. violaceum growth, and quorum sensing regulated pigment (violacein) production was studied by broth dilution assay. High performance liquid chromatography was also applied to generate chromatographic fingerprint of the active extracts. Effect of sub-minimum inhibitory concentration level of the antibiotic streptomycin on quorum sensing regulated pigment production was also studied.@*RESULTS@#Pongamia pinnata seed extracts and prodigiosin were found to possess anti-QS, and Manilkara hexandra and Pyrus pyrifolia seed extracts to possess QS-enhancing effect in C. violaceum. Dimethylsulfoxide was found to enhance violacein production, whereas ethanol and methanol reduced violacein production in C. violaceum. Streptomycin at sub-minimum inhibitory concentration level was able to significantly arrest QS-regulated pigment production in C. violaceum and Serratia marcescens.@*CONCLUSIONS@#Prodigiosin and the seed extracts used in this study could affect quorum sensing in C. violaceum to a notable extent. Results of this study also emphasize the importance of inclusion of appropriate solvent controls (negative controls) in bioassays designed for screening of antimicrobial and/or anti-QS compounds. Antipathogenic potential of low concentrations of streptomycin was also demonstrated.

Effect of certain natural products and organic solvents on quorum sensing in Chromobacterium violaceum

Objective: To investigate the effect of seed extracts of Pongamia pinnata, Pyrus pyrifolia, and Manilkara hexandra, bacterial pigment prodigiosin, and three organic solvents (ethanol, methanol, and dimethylsulfoxide), on quorum sensing (QS) in Chromobacterium violaceum (C. violaceum). Methods: C. violaceum was challenged with plant extracts prepared by microwave assisted extraction method, prodigiosin, and organic solvents. Effect of these test substances on C. violaceum growth, and quorum sensing regulated pigment (violacein) production was studied by broth dilution assay. High performance liquid chromatography was also applied to generate chromatographic fingerprint of the active extracts. Effect of sub-minimum inhibitory concentration level of the antibiotic streptomycin on quorum sensing regulated pigment production was also studied. Results: Pongamia pinnata seed extracts and prodigiosin were found to possess anti-QS, and Manilkara hexandra and Pyrus pyrifolia seed extracts to possess QS-enhancing effect in C. violaceum. Dimethylsulfoxide was found to enhance violacein production, whereas ethanol and methanol reduced violacein production in C. violaceum. Streptomycin at sub-minimum inhibitory concentration level was able to significantly arrest QS-regulated pigment production in C. violaceum and Serratia marcescens. Conclusions: Prodigiosin and the seed extracts used in this study could affect quorum sensing in C. violaceum to a notable extent. Results of this study also emphasize the importance of inclusion of appropriate solvent controls (negative controls) in bioassays designed for screening of antimicrobial and/or anti-QS compounds. Antipathogenic potential of low concentrations of streptomycin was also demonstrated.

Preparation of heme from duck blood by a new acidified acetone extraction method / 中国药学杂志

OBJECTIVE: To prepare heme from cherry valley duck blood. METHODS: Single factor experiments and orthogonal experiment were carried out to establish the optimal process of preparing heme from cherry valley duck blood by a new microwave-assisted acid acetone extraction method. RESULTS: Single factor experiments proved that the microwave-assisted extraction process significantly improved the extraction efficiency of heme. In addition, orthogonal experiment indicated the power of microwave and microwave extraction time had significant effects on the extraction results, and the optimum conditions of microwave-assisted extraction in laboratory were as follows: the power was 800 W, extraction time was 60 min, and the temperature was 50°C. CONCLUSION: The new microwave-assisted method, combining cell disruption and heme extraction process, can simplify the traditional acid acetone extraction process, and it is proved to be feasible.

Determinación de antocianinas mediante extracción asistida por radiación de microondas en frijol (Phaseolus vulgaris L.) de alto consumo en Antioquia-Colombia / Determination of anthocyanins by microwave assisted extraction in beans (Phaseolus vulgaris L.) commonly consumed in Antioquia, Colombia

Introducción: el frijol además de ser una fuente nutricional importante en Colombia, también aporta un gran contenido de sustancias con potencial benéfico para la salud, como son flavonoides y antocianinas, entre otras, que contribuyen de manera significativa con sus propiedades medicinales y pueden tener un efecto positivo contra algunas enfermedades crónicas. Objetivos: comparar el contenido de antocianinas del pericarpio del fruto de frijol de diferentes variedades con respecto al método de extracción. Métodos: la piel del fruto de frijol deshidratada y macerada se sometió a extracciones sólido-líquido y asistida por microondas con metanol acidulado. Se evaluó el contenido de antocianinas por el método de diferencial de pH y el potencial antioxidante in vitro con base en el método de DPPH (catión radical α-α-difenil-ß-picrilhidrazilo). Resultados: la técnica de extracción asistida por microondas (MAE) mostró una mayor eficiencia respecto a la convencional, porque disminuyó considerablemente la cantidad de solvente, de muestra empleada y los tiempos de extracción. Los extractos obtenidos presentaron un contenido de antocianinas entre 8,33 y 25,5 mg cianidin-3-glucósido/L, sin embargo, el efecto de protección antioxidante resultó similar entre ellos y comparable con el de las sustancias de referencia. Conclusiones: todos los extractos presentaron buena capacidad protectora contra radicales libres; la técnica de extracción asistida por microondas puede ser usada como método alternativo para una valoración rápida, eficiente y eficaz del contenido de sustancias bioactivas en diferentes matrices.

Introduction: apart from being an important nutritional source in Colombia, beans also provide a large amount of substances with potential beneficial effects on health, such as flavonoids and anthocyanins, among others, which stand out for their medicinal properties and potential positive action against some chronic diseases. Objectives: compare the content of anthocyanins in the pericarp of the fruit of different varieties of beans with reference to the extraction method. Methods: after dehydration and maceration, the bean fruit coat was subjected to solid-liquid and microwave assisted extraction with acidulated methanol. Anthocyanin content was determined by the pH differential method, and the cation radical α-α-diphenyl-ß-picrylhydrazyl (DPPH) method was used for determination of in vitro antioxidant potential. Results: microwave assisted extraction (MAE) proved to be more efficient than the conventional technique, with a considerable reduction in the amount of solvent, sample and extraction time. Anthocyanin content in the extracts obtained was between 8.33 and 25.5 mg cyanidin-3-glucoside/L. However, their antioxidant protection effect was similar and comparable to that of reference substances. Conclusions: all extracts showed good protective capacity against free radicals. Microwave assisted extraction may be used as an alternative method for fast, efficient and effective evaluation of the content of bioactive substances in various matrices.

Extracción asistida por microondas de lípidos de las semillas de Cucurbita pepo L. (calabaza) / Microwave-assisted extraction of Cucurbita pepo L. (pumpkin) seed lipids

Introducción: los lípidos presentes en las semillas de Cucurbita pepo L. ricos en ácidos grasos poliinsaturados han demostrado tener acción antiinflamatoria en la hiperplasia prostática benigna. El empleo de la energía de las microondas en la extracción de compuestos de origen natural tiene como ventaja principal, la rapidez del calentamiento, que permite significativos ahorros de tiempo y en consecuencia energía en el proceso, todo lo cual se manifiesta en una reducción de los costos en general. Objetivos: estudiar el efecto del tiempo en la obtención de los lípidos contenidos en las semillas de Cucurbita pepo L. mediante la extracción asistida por microondas. Métodos: se estudiaron diferentes tiempos (1, 5, 10 y 15 min) para extraer los lípidos de las semillas de Cucurbita pepo L., empleando etanol como disolvente. Se evaluó mediante espectroscopia de reflexión interna y cromatografía gaseosa la presencia de los ácidos grasos mayoritarios responsables de la actividad farmacológica. Resultados: se demostró que el tiempo de extracción de 1 min era el más adecuado. El análisis cualitativo y cuantitativo mediante espectroscopia de reflexión interna y cromatografía gaseosa, respectivamente, evidenció la presencia de los ácidos grasos en proporción mayoritaria reportados en la literatura con actividad sobre la hiperplasia prostática benigna. Conclusiones: los resultados demostraron la factibilidad del empleo de la energía de las microondas en la extracción del componente lipídico a partir de las semillas de Cucurbita pepo L

Introduction: lipids from Cucurbita pepo L. seeds, rich in polyunsaturated fatty acids, show an effective antiinflammatory effect in the treatment of benign prostatic hyperplasia (BPH). The use of microwave energy in the extraction of natural compounds has among its main advantages quick heating, which saves time and energy in the process, thus reducing the general costs. Objectives: to study different extraction times to obtain lipids from Cucurbita pepo L. seeds through microwave-assisted extraction. Methods: lipids from Cucurbita pepo L. seeds were extracted with ethanol as solvent at several times (1, 5, 10 y 15 min).The evaluation was based on attenuated total internal reflection spectrometry and gas chromatography to detect the major fatty acids responsible for the pharmacological action. Results: the one-minute extraction time was the most efficient. Qualitative and quantitative analysis by attenuated total internal reflection spectrometry and gas chromatography indicated the presence of the major fatty acids reported in the literature as having pharmacological effect over benign prostate hyperplasia. Conclusions: the results demonstrated the feasibility of employing microwave energy in the extraction of the lipid component from Cucurbita pepo L. seeds

Response surface optimization of microwave-assisted extraction for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii / 药物分析学报

Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol（1∶15,v/v）for 30 min,and then microwave irradiation for 11 min at a power of 600 W.Coupling the extraction process with HPLC-fluorescence presented good recovery,satisfactory precision,and good linear relation.Compared with a method from the Chinese Pharmacopoeia,the proposed method enables higher extraction efficiency and more accurate analytical results.It can be of potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.

Microwave-assisted extraction of flavonoids from Cajanus cajan leaves / 中草药

Objective: To select the proper method for extracting flavonoids from Cajanus cajan leaves and optimize the extraction parameters. Methods: Taking the extracting rate of orientoside, luteolin, and total flavonoids from C. cajan leaves and anti-oxidative activity as indexes, microwave-assisted method was compared with heat reflux extraction, ultrasound-assisted extraction, and maceration extraction. Central composite design was used for optimization of parameters affecting the extraction of orientoside and luteolin using microwave-assisted method. Results: The results showed that microwave-assisted extraction was the best method and the optimal conditions were: 50 mesh particle size, 80% ethanol aqueous, 1 : 20 material/ethanol aqueous, temperature 60°C, 4 times cycle, 10 min extraction time, 500 W extraction power. The extraction yields of orientoside and luteolin were (4.42 ± 0.01) and (0.10 ± 0.01) mg/g from dry C. cajan leaves, respectively. Conclusion: The microwave-assisted method is feasible with less time, higher extraction yield, and better anti-oxidative activity.

Study on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD / 药物分析学报

Microwave-assisted extraction (MAE) was used for extraction of effective components of sarcandra glabra (Thunb.), and then chromatographic fingerprint of sarcandra glabra (Thunb.) was studied by high performance liquid chromatography/diode array detector (HPLC/DAD). The conditions of MAE were optimized by an orthogonal experiment, and then the authentication and validation of the chromatographic fingerprint were conducted. Nine peaks were identified as common peaks in the fingerprint chromatograms, and isofraxidin was considered as a reference compound and quantified. Relative standard deviations of retention time and peak area of each component were less than 3% and 8%, respectively. Similarity and difference analysis were conducted by use of PCA and relation coefficient. Twenty batches of sarcandra glabra (Thunb.) samples from two different producing areas could be classified into two different groups in the PCA model. The results showed that MAE-HPLC/DAD method was simple, efficient and stable for the study of complex chromatographic fingerprint of sarcandra glabra (Thunb.), which could provide more reliable and precise information for quality evaluation.

Optimization of Microwave-assisted Extraction of Polyphenols from Enteromorpha prolifra by Orthogonal Test / 中草药·英文版

Objective To optimize microwave-assisted extraction of polyphenols from Enteromorpha prolifra.Methods Based on single-factor tests,an efficient microwave-assisted extraction(MAE)technique was developed to extract bioactive polyphenols from E.prolifra through orthogonal L16(4)5 test.Results The highest yield(0.923±0.013)mg/g was obtained when microwave power,solvent to raw material ratio,irradiation time,ethanol concentration,and extraction cycles were 500 W,25 mL/g,25 min,40%,and 3,respectively,which was higher than that of Soxhlet extraction with methanol for 6 h,ultrasound-assisted extraction with 40% ethanol for 1 h twice and heat reflux extraction with 40%ethanol for 2 h twice.Conclusion This finding indicates that MAE is a superior technique for the extraction of polyphenols due to less impurity,higher time efficiency and yield.

High performance liquid chromatography combined with microwave-assisted extraction and solid phase extraction in determination of mefenacet residues in rice / 第二军医大学学报

Objective: To establish a method by combining microwave-assisted extraction (MAE), solid phase extraction (SPE) and high performance liquid chromatography (HPLC) for determination of the mefenacet residues in rice. Methods: Acetone and acetontrile (3:7) were used as extraction solvent. Microwave-assisted extraction was used to extract mefenacet residues in the rice. The extracts were then cleaned up with a Florisil cartridge and then subjected to Hypersil C18 column(5 μm,4. 6 mm × 200 mm), with acetonitrile: water(50: 50,V/V)solution as mobile phase and with a flow rate of 1.0 ml/min: the ultraviolet detection wavelength was at 217 nm. Results: Good linear correlation for mefenacet was found within a concentration range of 0. 198-9. 900 μg/ml. The detection limit was 0. 039 6 μg/mL for mefenacet(S/N=2). The average recovery rate of rice hull and brown rice were 90.8% (RSD 1. 8%) and 85. 6% (RSD 2. 5%),respectively. Conclusion: The present method is simple and rapid: it can be used for the determination of mefenacet residues in rice.