Chen Xiaoqing

Microwave-assisted extraction of polysaccharides from solanum nigrum

The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the structures of polysaccharides were investigated. The extract was analyzed by the modified phenol-sulfuric acid method at 490 nm. The optimum experimental parameters were obtained by orthogonal experiments as follows: extraction time 15 min, microwave radiation power 455 W and the process ratio of materials mass to solvent volume 1:20. The results show that compared with the conventional reflux extraction, the microwave-assisted extraction has a higher yield in shorter time, with no effect on the finally obtained polysaccharides as seen from the FT-IR spectra. The scanning electron microscopy images reveal that the mechanism of the extraction is related to the structural changes of the plant cells in different extracting conditions.

Preparation and photocatalytic properties of Fe-doped TiO2 nanoparticles

Nanocrystalline Fe-doped TiO2 with size of 60 – 70 nm was prepared by a sol-gel technique, followed by freeze-drying treatment for 2 h. Thermogravimetric and differential thermal analyses, X-ray diffraction, scanning electron microscope, laser diffraction particle size analyzer and UV-Vis spectrophotometer technologies were used to characterize the product. The photocatalytic activities of the samples were evaluated by the degradation of wastewater of paper-making. The effects of Fe ion implantation on the photocatalytic activity of TiO2 were also discussed. The results show that the iron content plays an essential role in affecting the photocatalytic activity of the Fe-doped TiO2 and the optimum content of Fe-doped is 0.05% (mass fraction). The photocatalytic activity of samples with lower content of Fe-doped is higher than that of pure TiO2 in the treatment of paper-making wastewater. The photo-degradation effect of paper-making effluent is the best by means of Fe-doped TiO2 with 0.05% Fe.

Rapid screening and identification of α -glucosidase binding compounds in Chinese medicines by online affinity solid-phase extraction-high performance liquid chromatography-diode array detector-quadrupole time-of-flight mass spectrometry

中药活性成分的快速分离分析一直是中药研究的重点和热点问题。该文建立了在线亲和固相萃取-高效液相色谱-二极管阵列检测-四极杆飞行时间质谱技术快速筛选中药中与 α -葡萄糖苷酶有结合作用的活性成分的方法。四通阀和六通进样阀组成接口界面，收集亲和固相萃取柱中与 α -葡萄糖苷酶有结合作用的活性成分，接着进入液相色谱系统进行分析鉴定。阳性对照品（（+）-儿茶素）和阴性对照品（水杨酸）混合物筛选确定了方法的特异性和准确性。接着，以玉竹为研究对象，筛选出9种主要的 α -葡萄糖苷酶抑制活性化合物，包括5种苯乙基肉桂酰胺类化合物，4种双氢高异黄酮类化合物。结果表明建立的方法简便、快速、特异性强，可用于任何复杂体系中 α -葡萄糖苷酶结合活性成分的筛选。

Simultaneous determination of geniposidic acid, chlorogenic acid and geniposide in eucommia by HPLC

A high performance liquid chromatography (HPLC) method was established for simultaneous determination of geniposidic acid, chlorogenic acid and geniposide in eucommia. Detection at 240 nm with a reversed-phase column, CH3OH volume fraction, acidic additive and pH value of mobile phase were studied for their effects on the separability of the compounds. The most suitable separation was obtained with isocratic gradient elution system using CH3OH-H2O-H3PO4 (12.00 : 87.96 : 0.04, volume ratio) at a flow-rate of 1.0 mL/min. Under the experimental conditions, the capacity factors of three compounds are in 3–13. The sample is separated rightly. The analysis time is 30 min and the retention time of geniposidic acid, chlorogenic acid and geniposide are 6.7 min, 10.5 min and 21 min, respectively.