Enrichment and separation of antitumor triterpene acids from the epidermis of Poria cocos by pH‐zone‐refining counter‐current chromatography and conventional high‐speed counter‐current chromatography

Triterpene acids were extracted from the epidermis of Poria cocos (Schw.) Wolf. These acids were found to inhibit the growth of lung cancer cells in vitro and in vivo. An efficient method for the preparative separation of antitumor triterpene acids was established that involves the combination of pH‐zone‐refining counter‐current chromatography and conventional high‐speed counter‐current chromatography. We used pH‐zone‐refining counter‐current chromatography to concentrate the triterpene acids using a two‐phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (3:7:5:5, v/v/v/v), trifluoroacetic acid (10 mM) was added to the upper phase as a retainer, and ammonia (10 mM) was added to the lower phase as an eluter. As a result, 200 mg concentrate of triterpene acids was obtained from 1.0 g of crude extract. The concentrate was further separated by conventional high‐speed counter‐current chromatography using a solvent system composed of petroleum ether/ethyl acetate/methanol/water (0.8:1.2:1.2:0.9, v/v), yielding 50 mg of poricoic acid A and 5 mg of poricoic acid B from 120 mg concentrate, respectively. The inhibitory activity of the major compound on lung A549 cells was examined and poricoic acid A was found to significantly inhibit the growth of A 549 cells.     

Separation and purification of five alkaloids from Aconitum duclouxii by counter‐current chromatography

C₁₉‐diterpenoid alkaloids are the main components of Aconitum duclouxii Levl. The process of separation and purification of these compounds in previous studies was tedious and time consuming, requiring multiple chromatographic steps, thus resulted in low recovery and high cost. In the present work, five C₁₉‐diterpenoid alkaloids, namely, benzoylaconine ( 1 ), N‐deethylaconitine ( 2 ), aconitine ( 3 ), deoxyaconitine ( 4 ), and ducloudine A ( 5 ), were efficiently prepared from A. duclouxii Levl (Aconitum L.) by ethyl acetate extraction followed with counter‐current chromatography. In the process of separation, the critical conditions of counter‐current chromatography were optimized. The two‐phase solvent system composed of n‐hexane/ethyl acetate/methanol/water/NH₃·H₂O (25%) (1:1:1:1:0.1, v/v) was selected and 148.2 mg of 1 , 24.1 mg of 2 , 250.6 mg of 3 , 73.9 mg of 4, and 31.4 mg of 5 were obtained from 1 g total Aconitum alkaloids extract, respectively, in a single run within 4 h. Their purities were found to be 98.4, 97.2, 98.2, 96.8, and 96.6%, respectively, by ultra‐high performance liquid chromatography analysis. The presented separation and purification method was simple, fast, and efficient, and the obtained highly pure alkaloids are suitable for biochemical and toxicological investigation.     

One‐dimensional CuII coordination polymers containing C2h‐symmetric 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate linkers

Two new one‐dimensional Cu^II coordination polymers (CPs) containing the C_2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ⁴O,O′:O′′:O′′′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂]·H₂O}_n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ²O³:O^3′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂(H₂O)]·H₂O}_n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the Cu^II ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II).     

Synthesis,structure and characterization of two new metal–organic coordination polymers based on the ligand 5‐iodobenzene‐1,3‐dicarboxylate

Two new coordination polymers (CPs) formed from 5‐iodobenzene‐1,3‐dicarboxylic acid (H₂iip) in the presence of the flexible 1,4‐bis(1H‐imidazol‐1‐yl)butane (bimb) auxiliary ligand, namely poly[[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)butane‐κ²N³:N^3′](μ₃‐5‐iodobenzene‐1,3‐dicarboxylato‐κ⁴O¹,O^1′:O³:O^3′)cobalt(II)], [Co(C₈H₃IO₄)(C₁₀H₁₄N₄)]_n or [Co(iip)(bimb)]_n, (1), and poly[[[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)butane‐κ²N³:N^3′](μ₂‐5‐iodobenzene‐1,3‐dicarboxylato‐κ²O¹:O³)zinc(II)] trihydrate], {[Zn(C₈H₃IO₄)(C₁₀H₁₄N₄)]·3H₂O}_n or {[Zn(iip)(bimb)]·3H₂O}_n, (2), were synthesized and characterized by FT–IR spectroscopy, thermogravimetric analysis (TGA), solid‐state UV–Vis spectroscopy, single‐crystal X‐ray diffraction analysis and powder X‐ray diffraction analysis (PXRD). The iip²⁻ ligand in (1) adopts the (κ¹,κ¹‐μ₂)(κ¹, κ¹‐μ₁)‐μ₃ coordination mode, linking adjacent secondary building units into a ladder‐like chain. These chains are further connected by the flexible bimb ligand in a trans–trans–trans conformation. As a result, a twofold three‐dimensional interpenetrating α‐Po network is formed. Complex (2) exhibits a two‐dimensional (4,4) topological network architecture in which the iip²⁻ ligand shows the (κ¹)(κ¹)‐μ₂ coordination mode. The solid‐state UV–Vis spectra of (1) and (2) were investigated, together with the fluorescence properties of (2) in the solid state.     

Selective Template Removal by Thermal Depolymerization to Obtain Mesostructured Molybdenum Oxycarbide

The carbon content of mesostructured organic‐inorganic hybrid material of a cylindrical block copolymer template of poly(2‐vinylpyridine)‐block‐poly(allyl methacrylate) (P2VP‐b‐PAMA) and ammonium paramolybdate (APM) could be reduced by thermal depolymerization. By calcination in vacuo at 320 °C the PAMA core can be completely removed while the remaining P2VP brush preserves the mesostructure. The P2VP‐APM composite can then be carburized in‐situ to MoO_xC_y in a second pyrolysis step without any additional carbon source but P2VP. The molybdenum oxycarbide nanotubes obtained, form hierarchically porous non‐woven structures, which were tested as catalyst in the decomposition of NH₃. They proved to be catalytically active at temperatures above 450 °C. The activation energy was estimated from an Arrhenius Plot to be 127 kJ · mol^–1.     

Development of models for prediction of the antioxidant activity of derivatives of natural compounds

Antioxidants are important for maintaining the appropriate balance between oxidizing and reducing species in the body and thus preventing oxidative stress. Many natural compounds are being screened for their possible antioxidant activity. It was found that a mushroom pigment Norbadione A, which is a pulvinic acid derivative, shows an antioxidant activity; the same was found for other pulvinic acid derivatives and structurally related coumarines. Based on the results of in vitro studies performed on these compounds as a part of this study quantitative structure–activity relationship (QSAR) predictive models were constructed using multiple linear regression, counter-propagation artificial neural networks and support vector regression (SVR). The models have been developed in accordance with current QSAR guidelines, including the assessment of the models applicability domains. A new approach for the graphical evaluation of the applicability domain for SVR models is suggested. The developed models show sufficient predictive abilities for the screening of virtual libraries for new potential antioxidants.     

稀土萃取分离过程软测量方法的研究

分析了稀土组分含量在线检测技术进展缓慢的原因,分析了稀土萃取分离过程机制,找出影响稀土组分含量检测的主要因素,确定辅助变量。利用从包钢稀土厂采集的数据通过newrb函数创建径向基网络来实现稀土组分含量的软测量。文中通过流程图详细阐述了建模方法,采用50组样本数据对所建立的模型进行计算机仿真验证,仿真结果证明了模型的可行性。     

Exploring Network Formation of Tough and Biocompatible Thiol‐yne Based Photopolymers

This work deals with the in‐depth investigation of thiol‐yne based network formation and its effect on thermomechanical properties and impact strength. The results show that the bifunctional alkyne monomer di(but‐1‐yne‐4‐yl)carbonate ( DBC ) provides significantly lower cytotoxicity than the comparable acrylate, 1,4‐butanediol diacrylate ( BDA ). Real‐time near infrared photorheology measurements reveal that gel formation is shifted to higher conversions for DBC /thiol resins leading to lower shrinkage stress and higher overall monomer conversion than BDA . Glass transition temperature (T_g), shrinkage stress, as well as network density determined by double quantum solid state NMR, increase proportionally with the thiol functionality. Most importantly, highly cross‐linked DBC /dipentaerythritol hexa(3‐mercaptopropionate) networks (T_g ≈ 61 °C) provide a 5.3 times higher impact strength than BDA , which is explained by the unique network homogeneity of thiol‐yne photopolymers.

     

基于内源性致香物质和化学计量学的烟草感官评价研究

采用主成分分析法结合遗传算法和神经网络,建立了基于烟草内源性致香物质的感官质量评价预测模型。利用气相色谱-质谱(GC-MS)技术对超临界萃取-分子蒸馏所得烟草精油中的内源性致香组分进行定性定量分析,汇总各类致香指标后,对其进行主成分分析;以提取所得5个主成分的得分作为输入变量,感官评吸分数作为输出变量,分别使用标准BP神经网络和遗传算法(GA)优化的BP神经网络建立预测模型。对比实验结果表明,GA优化后的模型预测效果更优,其预测值与实验值间的相关系数为0.96,预测均方根误差为1.81,说明GA-BP模型具有更好的拟合能力和预测能力,该模型能有效地预测烟草精油的感官品质。     

数字图像法测定养殖水中的孔雀石绿

建立一种简单、可靠的养殖水中孔雀石绿的数字图像检测方法。以1-己基-3-甲基咪唑四氟硼酸盐离子液体富集水样品,再用手机拍照获取样品信息,最后用数字图像结合多层感知器神经网络定量分析孔雀石绿的含量。该法测定结果的相对标准偏差不大于6%(n=5),加标回收率为97.8%~103.0%。该方法可用于养殖水中孔雀石绿的含量测定。