ABSTRACT
Roselle (Hibiscus sabdariffaL.) is natural source of valuable components such as phenolics, flavonoids and anthocyanins. Anthocyaninis normally used in the food technology to replace synthetic pigments as well as medicinal properties due to antioxidants. Microwave irradiation is a feasible green solvent extraction method receiving great attention as it utilizes solvent at elevated temperature and controlled pressure conditions. Microwave extraction emerges as a promising inexpensive, simple and efficient technique. In our research, various variable like microwave power (20, 40, 60, 80, 100 W), microwave frequency (10, 20, 30, 40, 50 GHz), the micrwave irradiation duration (5, 10, 15, 20, 25 min), liquid to solid ratio (water: material, 2:1, 3:1, 4:1, 5:1, 6:1), extraction temperature (50, 55, 60, 65, 70C), number of extraction cycles (1, 2, 3, 4, 5) influencing to the microwave-assisted extraction of phytochemicals in roselle (Hibiscus sabdariffa L.)calyx were thoroughly examined. Total total phenolic (mg GAE/ 100g), total flavonoid (mg GE/ 100g), anthocyanin (mg/100g) were key indicators to define the optimal variable. Our resultsrevealed that microwave power at 80 W, frequency 40 GHz, duration 15 min, liquid to solid ratio 4:1, temperature 55C, 4 cycles of extraction were appropriate for extraction of phytochemical components inside roselle (Hibiscus sabdariffa L.)calyx
ABSTRACT
Objective: To establish the UPLC fingerprint of Salvia miltiorrhiza microwave extraction method and traditional extraction method and identify the main chromatographic peaks, the chemometrics method was used to compare the chemical differences of different extraction methods. Methods: The separation was performed on a chromatographic Waters ACQUITY UPLC BEH sheid C18 column (100 mm × 2.1 mm, 1.7 μm), with acetonitrile (A)-0.1% aqueous formic acid (B) as the mobile phase gradient elution. The flow rate was 0.3 mL/min, the detection wavelength was 270 nm, and the fingerprints of traditional extraction method and microwave extraction method of S. miltiorrhiza; The content of eight index components was determined, and SPSS 22.0 software was used for principal component analysis and t-test analysis to further evaluate the difference between microwave extraction method and traditional extraction method. Results: The traditional extraction method and the microwave extraction method respectively calibrate 16 and 17 common peaks, and the content of eight index components was different. In the similarity evaluation, the fingerprints of different extraction methods of S. miltiorrhiza were compared, and the similarity was > 0.945. The content of the index components and the comprehensive mass fraction of the index components in the microwave extraction method were higher than the traditional extraction method, and the mean value of the eight index components showed that the microwave extraction method was higher than the traditional extraction method. Compared with the traditional extraction method, there were significant differences in the content of salvianic acid A sodium, protocatechuic aldehyde, rosmarinic acid, lithospermic acid, salvianolic acid B, cryptotanshinone, and tanshinone IIA (P < 0.05, 0.01). Conclusion: Through the comparison of fingerprints and chemometric methods, the overall chemical composition of S. miltiorrhiza under different extraction methods is similar. The content of chemical components is different by t-test, and the content of S. miltiorrhiza microwave extraction method is higher than traditional extraction method. It is concluded that the microwave extraction method has certain advantages compared with the traditional extraction method. The establishment of this method can lay a foundation for the wide application of microwave extraction method in the field of traditional Chinese medicine.
ABSTRACT
AIM To optimize the ultrasound-microwave extraction for total flavonoids from Glycyrrhizae Radix et Rhizoma residue by response surface method.METHODS In addition to the index of extraction rate of total flavonoids for evaluation,the microwave power,extraction time,liquid-soild ratio and ethanol concentration were taken into consideration as influencing factors for the extraction optimization by response surface method on the basis of single factor test.RESULTS The optimal conditions,determined to be 125 W for microwave power,32 min for extraction time,28.4 ∶ 1 for liquid-solid ratio,79％ for ethanol concentration,and 300 W for extraction power,could bring forth a 2.59％ extraction rate of total flavonoids.CONCLUSION This stable and reliable method can be used for extracting total flavonoids from Glycyrrhizae Radix et Rhizoma residue.
ABSTRACT
OBJECTIVE: To establish a microwave extraction-HPLC method for determination of antioxidant 1010, antioxidant 330, antioxidant 1076, and antioxidant 168 in plastic infusion packaging materials and containers, and investigate the migration of the antioxidants from the materials to the injection. METHODS: Taking the contents of antioxidants as indices, the best extraction condition was determined with or thogonal experiments and statistical analysis. The separation of antioxidants was performed on a Sunfire-C18 (4.6 mm×150 mm, 5 μm) chromatographic column at 40℃, and the detection wavelength was set at 280 nm. The mobile phase consisted of acetonitrile, tetrahydrofuran, and water (6∶3∶1) at a flow rate of 1.5 mL·min-1, and the injection volume was 20 μL. RESULTS: The optimized extraction process was extracting 2 g of sample at 100℃ for 30 min. The calibration curves of antioxidant 1010, antioxidant 330, antioxidant 1076, and antioxidant 168 were linear over the concentration range from 0.004 to 0.5 mg·mL-1 (r=0.999 9) and the average recoveries of the antioxidants ranged from 96.8% to 103.7% (RSD<2%, n=9). CONCLUSION: This method is convenient, sensitive, and reliable and it can be used for the determination of antioxidants in plastic infusion materials and their migration to the injection.
ABSTRACT
Objective: To study the solvent-free microwave extraction for oils of Acori Tatarinowii Rhizoma and analyze the volatile components. Methods: The paper selected the best technological conditions by L9(34) orthogonal test, with the index of α-asarone, volume of volatile oils, and sum of the percentage, The essential oils in Acori Tatarinowii Rhizoma were analyzed with GC-MS. Results: The percentage of volatile oils was calculated according to peak area normalization method. The results showed similar amount of volatile oil components by two methods, and the extraction rates of α-asarone, β-asarone, and γ-asarone accounted for 4.12%, 55.11%, and 10.54% on the method of solvent-free microwave extraction, while the steam distillation was 5.39%, 47.03%, and 9.15%. To compare with two methods, solvent-free microwave extraction extracted volatile oil 0.235 mL and α-asarone 31.99 mg for 5 min, while steam distillation extracted volatile oil 0.175 mL and α-asarone 29.09 mg for 1 h. The method of solvent-free microwave extraction had the advantage of short reaction time and high yields. Conclusion: Solvent-free microwave extraction is a new method with shorter extracting time and better extracting efficiency.
ABSTRACT
Objective: To optimize the conditions of microwave technique in extraction of effective ingredients in Corydalis Rhizoma in the condition of pilot scale. Methods: Medicinal materials processing, microwave power, solvent concentration, liquid to solid ratio, extraction time and so on were investigated by single factor test on the extraction rate of tetrahydropalmatine, and on this basis, using the method of Box-Behnken the microwave extraction process of Corydalis Rhizoma was optimized. Results: The optimum process of microwave extraction of Corydalis Rhizoma was as follows: using drinking water as the extraction solvent, microwave power of 7 kW, liquid to solid ratio of 10:1, and extraction for 21 min. Under these conditions, the extraction rate of tetrahydropalmatine predictive value was 83.60%, and the verified value was 83.74%; and compared with water extraction, dry extract rate decreased by 70%. Conclusion: The mathematical model established is significant (P<0.01) and can analyze and forecast the microwave extraction technology of Corydalis Rhizoma.
ABSTRACT
Extraction process plays an important role in Chinese herbal medicine applications. Traditional extraction method has some disadvantages, such as long processing time, high solvent consumption and low efficiency. Thus, some new technologies and methods have been introduced in this paper, including ultrasonic extraction, microwave extraction, supercritical fluid extraction. On the basis of advantages and disadvantages of traditional Soxhlet extrac-tion, this paper mainly described the principles, characteristics, influencing parameters and applications.
ABSTRACT
This study was aimed to select the best microwave extraction craft conditions of polysaccharide from Radix platycodonis. The composite scores of polysaccharide content and yield rate were used as evaluation indexes. By ex-amining the impact of microwave power, microwave time, extraction times and solid-liquid ratio on crafts, the best craft conditions were optimized by orthogonal test. The orthogonal test showed that when the microwave power was 1800 W, microwave time was 8 min, extraction times were 3, solid-liquid ratio was 1:15, the composite scores were the highest and the extraction craft conditions were the best. It was concluded that the crafts are efficient and stable. It had laid a foundation for the further study on polysaccharide from R adix p latyc odonis .
ABSTRACT
Objective: To optimize the microwave extraction (ME) technology for extraction of total aconitum alkaloids and paeoniflorin in co-decoction of Aconiti Radix Cocta coupled with Paeoniae Radix Alba.. Methods: Orthogonal test with single factor, as well as ME method was used, 65% ethanol was optimized as extraction solvent, the effects of four factors, such as the microwave power, the radiation time, the solvent consumption, and ethanol concentration in microwave extraction process were investigated. The contents of total aconitum alkaloids were determined by UV-visible spectrophotometry and the paeoniflorin by HPLC by taking the contents and extract yield as evaluation indexes. Results: The optimum conditions of extraction were as follows: 65% ethanol as extracting solvent, the microwave power was 800 W, the radiation time was 0.5 h, the proportion of raw material to solvent was 1:10. In the condition, the highest extracting content and lowest extract yield of total aconitum alkaloids and paeoniflorin could be obtained. Conclusion: The optimized microwave extraction technology could be a potential way with the shorter time and higher extract yield and ME methods is better than the conventional extraction methods.
ABSTRACT
Object To study the ultrastructure destruction of plants in the process of microwave assisted solvent extracion and its mechanism.Methods Cell structures of fresh leaves of Ginkgo biloba L. were observed by transmission electron microscpoe.Results The cell structure changed when the leaves were under microwave radiation or soaked by solvents or heated, such as plasmoysis, destruction of cell organellaes, disappearance of starch grain and so on, while the cell wall was not broken both in microwave assisted solvent extraction and in traditional heating extraction.Conclusion Microwave radiation could lead to the relaxation of the cell structures, but not be enough to make the cell wall broken.
ABSTRACT
Object To explore the regularity of microwave extraction (ME) on Chinese medicines in different morphological structure and different polar compositions. Methods Anthraquinone in Radix et Rhizoma Rhei (RRR), Semen Cassiae (SC), cholorogenic acid in Flos Lonicerae, baicalin in Radix Scutellariae were determined as index compositions by HPLC. The extraction rate was measured by orthogonal design. Results ME selectivity to different anthraquinone in RRR is not significant, while at the same temperature, the extraction rates of emodin, chrysophanol, physcion in RRR are higher than those in SC. Conclusion The ME selectivity to the different morphological structure of Chinese medicines is obvious, but to the different polar compositions is not distinct.
ABSTRACT
Object A novel microwave-heated extraction (MHE) method was studied for the extraction of glycyrrhizic acid from Glycyrrhiza uralensis Fisch. Methods Several factors, such as temperature, time and microwave power were investigated and the appropriate MHE conditions were obtained from the orthogonal test. Under the optimum conditions, the optimal solvent was selected and the MHE was compared with ultrasonic extraction, leaching at room temperature and Soxhlet extraction,. Results The optimum conditions of MHE is extracting for another 40 min in 0.5% ammonia water after heated to 60 ℃ by microwave of 2 000 W. Yield of glycyrrhizic acid was about equal to that of Soxhlet extraction for 4 h, and that of leaching at room temperature for 44.3 h. Conclusion The MHE method is fast, efficient, energy-saving and high-selective, which is recommendable to the application to active compounds extraction from Chinese herbal medicines.
ABSTRACT
Objective: To evaluate the characteristic and explore the mechanism of microwave extraction (MAE) in extracting Chinese medicines by comparing with conventional extractions on Radix et Rhizoma Rhei. Methods : The sum of anthraquinone was determined by spectrophotometry and aphrostase in paraffin section was observed by microphotography. Results : Among the four methods, the efficiency of MAE was significantly the highest, which was 3.5 times of supersonic extraction and 1.5 times of Sohlex extraction and 1.5 times of decocting by water, respectively. The time of MAE was the shortest. MAE could destroy the cell organization to pick up the speed of dissolving. Conclusion : MAE is efficient, saving energy and time in extracting Chinese medicines.
ABSTRACT
Objective:The best operation condition of extraction was found through analyzing the influences of both process of microwave pretreatment and hot wave washing. Methods: A new extraction method of chlorogenic acid was that the dry FLos Lonicerae was humidified with 75% ethanol-water solution at first, then the wet Flos Lonicerae was rapidly vaporized by microwave heating, at last chlorogenic acid was extracted after hot water washed twice, 10 minutes each time. Results: Compared with traditional extraction, the extraction time was about less than 6 times and then extraction ratio was increased by 1%. Conclusion: The method has high rate of extraction and short time of extraction.