Advanced Materials Research Vols. 550-553

Abstract: Imperatorin and isoimperatorin are important components of Angelica dahurica with many beneficial functions to human health. In this study, an ultrasound-assisted extraction technique has been developed for the fast extraction of imperatorin and isoimperatorin from Angelica dahurica root. The high extraction yield of imperatorin and isoimperatorin was obtained under optimum extraction conditions: ultrasonication time 20 min, extraction temperature 30°C, ultrasound power 240w, ethanol concentration 80%, and ratio of solvent volume to sample weight 12:1 (ml/g), particle size 60 meshes. Compared to heat-reflux extraction, ultrasound-assisted extraction reduced extraction time and obtained higher percentage extracted of imperatorin and isoimperatorin. Scanning electron micrographs revealed that ultrasound could result in the destruction of cell walls, which increased the mass transfer rate of the solvents into the root materials

Abstract: Ultrasonic assisted multistage countercurrent extraction technique of ginsenosides Rb1, Rb2, Rc, Rd, Re, Rg1, and Rg2 from Panax quiquefolium L. was developed in this paper. It provides the analytic technique to determine simultaneously the seven major ginsenosides. The effects of ethanol concentration, ratio of liquid to solid, extraction temperature and extraction time on the extraction yields of the seven ginsenosides and total ginsenosides from Panax quiquefolium L.were investigated. The optimal process condition of ultrasonic assisted four-stage countercurrent extraction (4-UAMSCCE) was found using orthogonal array experimental design technique: 70% (v/v) ethanol solution, liquid: solid ratio of 10 ml/g, extraction temperature 45°C and extraction time 30 min. Under optimum process condition, the extraction efficiency of 4-UAMSCCE had been compared with those of conventional techniques including heat distillation extraction (HDE), ultrasonic assisted extraction (UAE), four-stage countercurrent extraction (4-MSCCE). Results show that the 4-UAMSCCE offers the highest ginsenosides extraction rate and considerable savings in time, energy and solvent consumption.

Abstract: The chemical constituents were isolated from the ethyl acetate fraction from ethanol extract of Selaginella doederleinii Hieron by column chromatography on silica gel and Sephadex LH-20. The chemical structures of six biflavones were elucidated on the basis of physicochemical properties and spectroscopic data as amentoflavone (1), robustaflavone 7,4',7''-o-trimethyl ether (2), heveaflavone (3), podocarpusflavone A (4), robustaflavone 4',4'''-o-dimethyl ether (5) and robustaflavone 4'-o-methyl ether (6). Biflavones 2, 4 and 5 were obtained from Selaginella doederleinii Hieron for the first time.

Abstract: Gypenosides III is a major bioactive component which is rich in Gynostemma pentaphyllum. For better utilization of the native resource, response surface methodology was used to optimize the extraction conditions of gypenosides III from G. pentaphyllum. The effects of three independent variables on the extraction yield of gypenosides III were investigated and the optimal conditions were evaluated by means of Box-Behnken design. The optimal conditions are as follows: ratio of ethanol to raw material 25, extraction temperature 58°C and ultrasonic time 25min. Under these conditions, the yield of gypenoside III is 1.216±0.05%, which is agreed closely with the predicted yield value.

Abstract: The antimicrobial of crude extract from pomelo peel on Staphylococcus aureas was investigated. Four organic solvents including 95% ethanol, dichlorometane, hexane and ethyl acetate, were used to extract the crude extract from pomelo peel. The antimicrobial activity of the crude extract was evaluated by detection of clear zone of inhibition. The experimental results showed that yield of yield of 95% ethanol, dichlorometane, hexane and ethyl acetate crude extract were 0.46, 0.57, 0.25, and 0.19%, respectively. Crude extract from pomelo peel can be used to inhibit Staphylococcus aureus. The clear zones of inhibition of 95% ethanol, dichlorometane, hexane and ethyl acetate crude extract were 7.88, 8.83, 7.88, and 7.54 mm, respectively.

Abstract: A simple, clean and economical way of separation and preparation noncaffeine tea polyphenols from green tea waste in one-step by Sephadex LH-20 column chromatography was developed. 20% (v/v) ethanol solution was used for removing caffeine and other components in the first stepwise elution, and tea polyphenols was eluted with 60% (v/v) ethanol solution by using reversed flow in the second stepwise elution. The yield of tea polyphenols above 11% with the purity about 98% and the content of catechins more than 91%, and the content of caffeine in tea polyphenols have not been detected by high-performance liquid chromatography. The recovery of tea polyphenols by column chromatography were about 86%, and the stability of preparative way is very good. Compared with conventional extraction and decaffeination ways, this way has more excellent advantages, such as cheaper raw material, no toxic residues, higher yield, commercially feasible and environment friendly.

Abstract: Urtica angustifolia (U. angustifolia) is a traditional medicinal material which has anti-inflammatory and detoxification functions. It contains some active ingredient, such as alkaloids, flavonoids and polysaccharides. The objective of this study was to separate and identify alkaloids form it. However, the test of extraction conditions was shown that alkaloids reached the maximum in 1:10 of liquid to material, 85% ethanol concentration, 2h of reflux extraction. The total alkaloids were purified by AB-8 resin column, silica gel column and acid dye experiment successively.In addition, the maximum absorption wavelength of U. angustifolia alkaloid was determined by UV spectrophotometry, followed by their structural identified and analysis for alkaloids by infrared spectroscopy, high performance liquid chromatography and mass spectrometry. It could be concluded that the alkaloids of U. angustifolia which contain monoterpene from incarvillea alkaloids. And its molecular weight and molecular formula had identified.

Abstract: The hot water method conditions of extracting oligosaccharides from asparagus are: extraction temperature: 80°C, extraction time: 90min, solid-liquid ratio: 1:20, ethanol final concentration: 80%, ethanol precipitation time: 8h and extraction times: 2. Different auxiliary treatments were tested to enhance the extraction ratio and it was improved from 3.842% to 9.638% after microwave freeze-thawing. Comparing of oligosaccharides contents between purple asparagus and green asparagus in different parts, the results showed that the oligosaccharides content in purple asparagus is about 3.5 times as that in green asparagus, and the oligosaccharides content of peel is higher than that of pulp in both asparagus. Different purification tests showed that combined action of papain and Sevag obtained a better effect.

Abstract: For better development of the function composition of maca, combined ultrasonic and microwave method was used to extract glucosinolates of maca in this paper. The ultrasonic-microwave combined power, time, solution to solid ratio, and the volume fraction of ethanol were studied by conducting single factor tests. The optimization results showed that the collaborative of ultrasonic and microwave was in favour of extracting glucosinolates of maca. The best condition was that ultrasonic-microwave combined power 470W, time 70s, solution to solid ratio were 30:1(mL:g), and the volume fraction of ethanol was 66%, the actual content of glucosinolates of maca can reach to 0.51%, was 0.12% lower than Soxhlet extraction method.

Abstract: Subcritical water extraction (SWE) is introduced in the extraction of ginger bioactive compounds, namely 6-gingerol and 6-shagoal. The extraction mechanism is identified using mass transfer coefficient model. The overall mass transfer coefficient, k or driving force for each compound is measured through experimental determination. Compound identification and analysis iss conducted using High Performance Liquid Chromatography (HPLC). The k value for 6-gingerol and 6-shagoal under optimized condition (130°C, 3.5MPa) of 28:3 (ml:g) solvent to sample ratio are 0.02849 cm/min and 0.04873 cm/min, respectively.