高速逆流制备分离中药黄柏中的生物碱

 利用高速逆流对传统中药黄柏中的生物碱类活性成分进行了制备分离。两相溶剂分离系统采用氯仿 甲醇 0 5mol/LHCl(体积比为 2∶1∶1) ,并对制备物进行了薄层分析。证实了生物碱成分 ,检出了小檗碱。     

Development and thermodynamic evaluation of novel lipid raft stationary phase chromatography for screening potential antitumor agents

Novel lipid raft stationary phase chromatography (LRSC), with lipid rafts that contain abundant tropomyosin‐related tyrosine kinase A receptors immobilized on the stationary phase, was developed for a high‐throughput screening of potentially active antitumor agents. Lestaurtinib was used as a model compound to determine the operational parameters of the LRSC. Of all the factors considered, the particle size of column packing, the column temperature and the flow rate were of immense importance in determining the performance of the established LRSC system. In order to profoundly comprehend the binding interaction between the model drug and the receptors on the column, thermodynamic studies were employed. The results revealed that the interaction was spontaneous and exothermic, a typical enthalpy‐driven process. Additionally, the primary forces were hydrogen bonding and van der Waals forces. In evaluating the applicability of the method, active extracts from Albizziae Cortex were screened out using the LRSC system under the optimized conditions. The bioactive components were successfully confirmed by the MTT assay. In conclusion, it could be said that the LRSC is a good model for screening potential antitumor agents because of its viability, rapid response and scalable features. Copyright © 2014 John Wiley & Sons, Ltd.     

Polyethylene glycol-based ultrasound-assisted extraction of magnolol and honokiol from Cortex Magnoliae Officinalis

In this study, a kind of green solvent named polyethylene glycol (PEG) was developed for the ultrasound-assisted extraction (UAE) of magnolol and honokiol from Cortex Magnoliae Officinalis. The effects of PEG molecular weight, PEG concentration, sample size, pH, ultrasonic power and extraction time on the extraction of magnolol and honokiol were investigated to optimise the extraction conditions. Under the optimal extraction conditions, the PEG-based UAE supplied higher extraction efficiencies of magnolol and honokiol than the ethanol-based UAE and traditional ethanol-reflux extraction. Furthermore, the correlation coefficient (R²), repeatability (relative standard deviation, n = 6) and recovery confirmed the validation of the proposed extraction method, which were 0.9993–0.9996, 3.1–4.6% and 92.3–106.8%, respectively.     

Rapid analysis of pseudolaric acids in Cortex Pseudolaricis and related medicinal products by high performance liquid chromatography

A simple, rapid, reverse-phase high performance liquid chromatographic method was developed for the quantitative analysis of pseudolaric acids in Cortex Pseudolaricis and its related medicinal products. With a C₁₈ analytical column (4.6 mm × 150 mm i.d.), five pseudolaric acids, namely pseudolaric acids A-C, pseudolaric acid A-O-β-d-glucopyranoside and pseudolaric acid B-O-β-d-glucopyranoside, were well separated within 7 min. Acetonitrile and 0.10% acetic acid were used as the mobile phase in a gradient program. The UV detection wavelength was set at 260 nm. The detection limits and quantification limits ranged in 8.26-16.66 ng/ml and 27.54-55.53 ng/ml, respectively. The intra- and inter-day variations were less than 1% for all five compounds. The recovery of all spiked pseudolaric acids ranged from 99.1% to 101.9%. Compared to existing analytical methods, this new method not only used two more important chemical markers but also provided a fivefold reduction in analysis time. In addition, the extraction method of herb sample was also modified by an orthogonal array experiment on three variable parameters: extraction time, solvent volume, and extraction cycles. The optimized extraction method was much simpler and could be efficiently used to analyse large set of herbal materials and related medicinal products. Nineteen herb samples collected from different regions of China and five related products were examined with this new analytical method. The results showed that this method is effective in distinguishing adulterants and unqualified products.     

Curvilinear reconstruction of 3D magnetic resonance imaging in patients with partial epilepsy: A pilot study

In an attempt to better delineate the abnormalities associated with focal cortical dysgenesis, we performed curvilinear reformatting of the cortex from 3D magnetic resonance (MR) images. Illustrative patients with partial seizures and conventional orthogonal MRI evaluation show that small regions of cortical thickening suggestive of focal dysplastic lesions may not be recognized. In three such patients the curvilinear reformatting demonstrated two additional focal abnormalities of the cortical gyri and better defined the two focal lesions found on conventional orthogonal MR images. This method promises to a be useful tool in the evaluation of epileptic patients with proven or suspected subtle structural cortical abnormalities, particularly focal neuronal migration disorders where cortical thickening, abnormal gyral pattern, and poor delineation of the gray-white matter transition are the main findings.     

Preparation and Characteristics of Esculin‐Imprinted Polymers

Four molecularly imprinted polymers (MIPs) were prepared in MeOH with esculin (=6,7‐dihydroxycoumarin 6‐(β‐D ‐glucopyranoside)=6‐(β‐D ‐glucopyranosyloxy)‐7‐hydroxy‐2H‐1‐benzopyran‐2‐one) as the imprinted molecule, methacrylic acid (=2‐methylprop‐2‐enoic acid; MAA), acrylamide (=prop‐2‐enamide; AM), 4‐vinylpyridine (=4‐ethenylpyridine; 4‐VP), or 2‐vinylpyridine (=2‐ethenylpyridine; 2‐VP) as the functional monomer, respectively, as well as ethylene glycol dimethacrylate (=2‐methylprop‐2‐enoic acid ethane‐1,2‐diyl ester; EGDMA) as the cross‐linking agent. The interaction between the template and the functional monomers was investigated by fluorescence and UV spectrophotometry, respectively, which revealed the presence of esculin/monomer complexes in the stoichiometric ratio 1 : 2 in the pre‐polymerization mixture. The resultant polymers were studied in equilibrium binding experiments to evaluate the recognition ability and the binding capacity towards esculin. The results showed that MIP₁, prepared with MAA as the functional monomer, exhibited advantageous characteristics of high binding capacity, optimal imprinting effect, and good selectivity towards esculin. The Scatchard analysis indicated that there are two types of binding sites in MIP₁, and its binding parameters including the apparent maximum numbers of binding sites and the dissociation constants were calculated. Finally, by packing an SPE column (SPE=solid‐phase extraction) with MIP₁, the esculin was separated and enriched successfully by this sorbent from samples of Cortex fraxini, and the average recovery was up to 74.7%.     

牡丹皮中有效成分丹皮酚的毛细管电泳快速检测新方法

采用毛细管电泳高频电导法对丹皮酚进行了快速分离检测。对电泳介质的种类及浓度、操作电压和进样时间等影响因素进行了优化。最佳条件为：分离介质1．0mmol／LH3BO3-3．0mmol／L三乙胺-10％CH，OH（pH=8．0），分离电压20．0kV，25．0cm位差虹吸进样8．0s。在该条件下。可在4min内实现对丹皮酚的分离检测。线性范围为2．0～105μg／mL，检出限为0．3μg／mL。成功测定了中药牡丹皮中的丹皮酚，回收率达94％～99％。方法简便、快速、灵敏，可用于药物分析。     

丹皮药材的高效液相色谱-质谱/质谱研究

采用高效液相色谱．质谱／质谱建立了丹皮药材的指纹图谱方法。丹皮药材中的主要成分得到较好分离,指纹峰重现性好,通过多维联用技术获得各指纹峰的保留时间、分子量及结构信息,推测出15个指纹峰的可能组成。结果表明：所建立的丹皮指纹图谱信息量丰富,对丹皮药材的化学表征及质量评价有重要的参考价值。     

High-resolution fMRI of macaque V1

To understand the physiological mechanisms underlying the blood-oxygenation-level-dependent (BOLD) signal, the acquisition of data must be optimized to achieve the maximum possible spatial resolution and specificity. The term "specificity" implies the selective enhancement of signals originating in the parenchyma, and thus best reflecting actual neural activity. Such spatial specificity is a prerequisite for imaging aimed at the elucidation of interactions between cortical micromodules, such as columns and laminae. In addition to the optimal selection of functional magnetic resonance imaging pulse sequences, accurate superposition of activation patterns onto corresponding anatomical scans, preferably acquired during the same experimental session, is necessary. At high resolution, exact functional-to-structural registration is of critical importance, because even small differences in geometry, that arise when different sequences are used for functional and anatomical scans, can lead to misallocation of activation and erroneous interpretation of data. In the present study, we used spin-echo (SE) echo planar imaging (EPI) for functional scans, since the SE-BOLD signal is sensitive to the capillary response, together with SE-EPI anatomical reference scans. The combination of these acquisition methods revealed a clear spatial colocalization of the largest fractional changes with the Gennari line, suggesting peak activity in Layer IV. Notably, this very same layer coincided with the largest relaxivity changes as observed in steady-state cerebral blood volume measurements, using the intravascular agent monocrystalline iron oxide nanoparticles (MION).