Sonochemical application reduces monosaccharide levels and improves cryoprotective effect of Jerusalem artichoke extract on Leuconostoc mesenteroides WiKim33 during freeze-drying

Lactic acid bacteria (LAB) are being used for probiotic and starter cultures to prevent global damage to microbial cells. To retain the benefits of LAB in the commercially used powdered form, highly efficient cryoprotective agents are required during the manufacturing process. This study suggests a novel cryoprotective agent derived from Jerusalem artichoke (JA; Helianthus tuberous L.) and describes the mechanism of cryoprotective effect improvement by sonication treatment. The cryoprotective effect of JA extract was verified by examining the viability of Leuconostoc mesenteroides WiKim33 after freeze-drying (FD). Sonication of JA extract improved the cryoprotective effect. Sonication reduced fructose and glucose contents, which increased the induction of critical damage during FD by 15.84% and 46.81%, respectively. The cryoprotective effects of JA and sonication-treated JA extracts were determined using the viable cell count of Leu. mesenteroides WiKim33. Immediately after FD and storage for 24 weeks, the viability of Leu. mesenteroides WiKim33 with JA extract was 82.8% and 76.3%, respectively, while that of the sonication-treated JA extract was 95.2% and 88.8%, respectively. Our results show that reduction in specific monosaccharides was correlated with improved cryoprotective effect. This study adopted sonication as a novel treatment for improving the cryoprotective effect and verified its efficiency.     

红外光谱结合判别分析对三七道地性及产地的鉴别研究

利用傅里叶变换红外光谱结合判别分析对三七的道地性及产地进行鉴别研究。测试了11个县13个种植点的136株三七主根样品的红外光谱,利用Omnic8.0软件计算了每个样品红外光谱的二阶导数光谱。分别采用1 800~700cm-1光谱范围的红外光谱数据和二阶导数光谱数据,运用逐步判别分析法建立模型对三七的道地性进行判别研究,二阶导数光谱数据建立的模型对三七道地性的识别效果更好,回判正确率为100%,预测正确率为93.4%。采用交叉验证法检验了模型的稳定性,并对此方法进行了外推性验证。用二阶导数光谱数据结合相同的判别方法对三七的产地进行识别,比较了不同光谱范围和不同训练样本数建立的模型判别效果,每个种植点选择8个样本作为训练样本,采用1 500~1 200cm-1光谱范围的数据建立的模型判别效果较好,回判正确率为99.0%,预测正确率为76.5%。结果表明,红外光谱结合判别分析对三七道地性的识别效果好,有望成为实际中鉴别三七道地性的新方法;对三七产地的识别有一定的效果,可作为三七产地鉴别的一种新思路。     

A monoclinic form of dendocarbin A: a borderline case of one‐dimensional isostructural polymorphism

The title compound, dendocarbin A [systematic name: (1R,5aS,9aS,9bR)‐1‐hydroxy‐6,6,9a‐trimethyldodecahydronaphtho[1,2‐c]furan‐3‐one], C₁₅H₂₂O₃, is a sesquiterpene lactone isolated from Drimys winteri var chilensis. The monoclinic phase described herein displays an identical molecular structure to the orthorhombic phase that we reported previously [Paz Robles et al. (2014). Acta Cryst. C 70 , 1007–1010], while varying significantly in chain pitch, and can thus be considered as a borderline case of one‐dimensional isostructural polymorphism.     

High-performance liquid chromatographic assay for the active saponins from Panax notoginseng in rat tissues

A reversed-phase liquid chromatographic method was used to determine the ginsenosides Rg1, Rb1 and Rd of Panax notoginseng in rat tissues (kidney, liver, heart, spleen and lung) after the administration of total saponins of P. notoginseng. The tissue samples were treated with solid-phase extraction prior to HPLC. The calibration curves for the three saponins were linear in the given concentration ranges. The intra-day and inter-day assay coefficients in tissues were between 76 and 120% respectively. The recoveries of all the tissues were higher than 70%. This method was applied to evaluate the distribution of the three major saponins of P. notoginseng in rat tissues.     

分子印迹聚合物选择性富集长春碱的研究

分子印迹聚合物(MIPs)是近年来发展起来的一种对特定分子(模板分子)具有高度选择性的合成高分子材料.本文以长春碱(VLB)为模板分子,以甲基丙烯酸(MAA)为功能单体、乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,在偶氮二异丁腈(AIBN)的引发下制备了长春碱印迹聚合物(VLB-MIP).采用紫外光谱对VLB与MAA之间形成的模板-功能单体复合物进行了分析,通过扫描电镜(SEM)对制备的VLB-MIP的表面形态进行了表征,并用BET法对MIP表面的孔径进行了测定.结果表明,VLB-MIP与未加模板分子制备的非印迹聚合物(NIP)相比表面多孔、粗糙,比表面积显著增加.以VLB-MIP作为固相萃取(SPE)的吸附剂,对VLB-MIP的选择性进行了评价,VLB-MIP能特异性地吸附VLB,而对VLB的结构类似物长春新碱(VCR)却没有表现出明显的吸附行为.将长春花提取物上样于填充VLB-MIP的SPE柱上,在最优实验条件下,长春花提取物中的VLB能被高效富集.此外,上样溶剂对MIP柱的吸附容量有影响,长春花提取物溶于非极性溶剂甲苯时,MIP的吸附容量最大为750μg/g,其次是氯仿吸附容量为625μg/g,最小的是甲醇为250μg/g.     

Preparative isolation and purification of ginsenosides Rf,Re, Rd and Rb1 from the roots of Panax ginseng with a salt/containing solvent system and flow step-gradient by high performance counter-current chromatography coupled with an evaporative light scattering detector

Ginseng is a popular herb worldwide and has had varied uses in traditional Asian medicine for thousands of years. There are several different species of the herb, but all share the same constituents. Ginsenosides, the most extensively studied chemical components of ginseng, are generally considered to be one of the most important active ingredients of the plant. In this study, we have developed fast and efficient methodology for isolation of four known ginsenosides Rf, Rd, Re and Rb1 from Ginseng by high performance counter-current chromatography (HPCCC) coupled with evaporative light scattering detection (ELSD). The crude sample for HPCCC was purified firstly from a ginseng extraction using macroporous resin. The enriched saponin fraction (480 mg) was separated by using methylene chloride–methanol–5 mM aqueous ammonium acetate–isopropanol (6:2:4:3, v/v,) as the two-phase solvent system and yielded 10.7 mg of Rf, 11.0 mg of Rd, 13.4 mg of Re and 13.9 mg of Rb1. The purity of these ginsenosides was 99.2%, 88.3%, 93.7% and 91.8%, respectively assessed by HPLC-DAD-ELSD, and their structures were characterized by electrospray ionization mass spectrometry (ESI-MS) and compared with standards. Ammonium acetate was used to shorten the separation time and eliminate emulsification together with a flow step-gradient. The salt can be removed by re-dissolving the sample using acetone.     

Microwave-assisted phase-transfer catalysis for the rapid one-pot methylation and gas chromatographic determination of phenolics

Microwave-assisted phase-transfer catalysis (PTC) is reported for the first time, for the one-step extraction–derivatization–preconcentration and gas chromatographic determination of twenty phenols and ten phenolic acids. The well established phase-transfer catalytic methylation is largely accelerated when heating is replaced with the “greener” microwave irradiation. The overall procedure was thoroughly optimized and the analytes were determined by GC/MS. The method presented adequate analytical characteristics being more sensitive in analyzing phenols than phenolic acids. The limits of detection without any additional preconcentration steps (e.g. solvent evaporation) were adequate and ranged from 0.4 to 15.8 ng/mL while limits of quantitation were between 1.2 and 33.3 ng/mL. The method was applied to the determination of phenols, in spiked environmental samples and phenolic acids in aqueous infusions of commercially available pharmaceutical dry plants. The recoveries of fortified composite lake water samples and Mentha spicata aqueous infusions ranged from 89.3% to 117.3% for phenols and 93.3% to 115.2% for phenolic acids.     

Flow injection potentiometric detection of trimethylamine in seafood using tungsten oxide electrode

A simple flow injection gas/diffusion method for the determination of trimethylamine (TMA) in seafood with potentiometric detection using tungsten oxide electrode has been developed. The method is based on the diffusion of TMA through a PTFE membrane from a sodium hydroxide donor stream to a phosphate buffer acceptor stream. The TMA in the acceptor stream passes through an electrochemical flow cell containing a tungsten oxide wire and a silver/silver chloride electrode, where TMA was sensitively detected. The parameters affecting the sensitivity of the electrode such as sodium hydroxide concentration, buffer concentration, pH, flow rate and injected volume were studied in details. The electrode response was linear in the concentration range from 1 to 10 μg ml⁻¹ TMA with a correlation coefficient (R²) of 0.991 and a detection limit of 0.05 μg ml⁻¹ TMA. The intra- and inter-days precision (R.S.D.) was found to be, respectively, 1.20 and 1.6% (n=6). The method was applied to the determination of TMA in fish tissue and recoveries of 99-100% were obtained for fish extracts. Results were in close agreement with those obtained by the existing classical official method. Common interference from those species that can diffuse through the membrane were removed by the addition of formaldehyde to the seafood extract. The method is simple, feasible with satisfactory accuracy and precision and thus, could be used for monitoring seafood quality with a sampling rate of 20±2 sample h⁻¹.     

Microwave-assisted extraction of ginsenosides from ginseng root

The extractions of ginsenosides Rg₁ and Rb₁ from ginseng root under atmospheric pressure by focused microwave-assisted technique have been investigated. The parameters used for the optimization were solvent composition, extraction time, and applied microwave power. The ginsenosides were quantified by high-performance liquid chromatography equipped with UV/Vis detector. The results of the 15-min microwave-assisted extraction (0.28% of Rg₁ obtained in 70% water-ethanol and 1.31% of Rb₁ obtained in 30% water-ethanol under 150 W of microwave power) were better than that from 10-h conventional solvent extraction (0.22% of Rg₁ and 0.87% of Rb₁ obtained in 70% water-ethanol).     

人参和五灵脂配伍的无机元素含量测定

采用电感耦合等离子体发射光谱法(ICP-AES)测定了人参和五灵脂配伍的无机元素含量。结果表明，人参和五灵脂及其合煎液中的铝含量均低于人参单煎液，人参和五灵配伍可减少有害元素铝的溶出；配伍合煎液中钙、硒、钼、钴、镁、铜、锰等有益元素的含量均高于人参单煎液。