Spectrum–effect relationship of antioxidant and anti-inflammatory activities of Laportea bulbifera based on multivariate statistical analysis

Laportea bulbifera, named Hong He Ma in Chinese, is a Chinese herbal medicine commonly used by the Miao nationality of China. In this study, 43 batches of L. bulbifera were collected from different origins in China. Ethanol, ethyl acetate and petroleum ether were used to prepare different extracts of the plant. UHPLC technique was used to establish the fingerprints, whereas DPPH assay and RAW264.7 inflammatory cell models were used to evaluate the antioxidant and anti-inflammatory activities, respectively. Moreover, the spectrum–effect relationship between relative peak area of common peaks and efficacy value was set up by multivariate statistical analysis. Furthermore, 10 batches were selected randomly for validation of those models. The results showed that ethyl acetate and petroleum ether extracts possess excellent antioxidant and anti-inflammatory activities, respectively. Peaks A₆ and A₇ demonstrated the greatest antioxidant activity, while peak A₁₇ showed the strongest anti-inflammatory activity. After a verified experiment, the result was obtained and illustrated that the spectrum–effect relationship which we established could reliably infer antioxidant and anti-inflammatory compounds of the Chinese herbal medicine.     

矿物元素指纹图谱的建立及在西洋参产地鉴别中的应用研究

采用电感耦合等离子体质谱法测定了山东、吉林、美国和加拿大4个产地西洋参中50种矿物元素的含量,研究了不同产地西洋参矿物元素的差别和转换系数,构建了西洋参的矿物元素指纹图谱。以各产地矿物元素含量的平均值构建了山东、吉林、美国和加拿大产西洋参的矿物元素标准指纹图谱。采用SPSS 20.0计算了各西洋参矿物元素指纹图谱与其矿物元素标准指纹图谱的相似度,确定了山东、吉林、美国和加拿大产西洋参矿物元素指纹图谱的相似度阈值分别为0.93、0.91、0.98和0.93。通过比较未知产地西洋参矿物元素指纹图谱与矿物元素标准指纹图谱的相似度,进行西洋参的产地判别。采用20批未知产地西洋参样品验证模型的准确性,正确率为85%。此外,研究表明,不同生长年限和不同部位西洋参样品对所建立的西洋参产地鉴别方法无影响。     

Comprehensive evaluation of chemical stability of Xuebijing injection based on multiwavelength chromatographic fingerprints and multivariate chemometric techniques

A strategy for monitoring and analyzing the chemical stability of Xuebijing injection (XBJ) by multiwavelength chromatographic fingerprints and multivariate classification techniques is presented in this paper. Multiwavelength chromatographic fingerprints were constructed using chromatographic data obtained at four wavelengths (260, 280, 320, and 400?nm). The raw chromatography data were preprocessed by noise reduction, baseline correction, data normalization, and interval correlation optimized shifting (icoshift). Using this method, fingerprints of 166 samples of XBJ subjected to different forced degradation conditions (irradiation, high temperature, and a range of pH values) were properly represented. Forty-one chemical components were identified using the iPeak program. In addition, the identified peak area profiling of chemical components were used for multivariate classification analysis. Principal component analysis (PCA) and Ward’s method were used to classify different XBJ degradation samples. The PCA score plot showed that XBJ degradation samples were clustered into four groups, and the results are confirmed by Ward’s method. Ten key chemical markers under different degradation conditions were found and identified by counterpropagation artificial neural networks (CP-ANN), statistical t-tests, and UPLC-Q-TOF-MS. The results suggest that the proposed strategy could be successfully applied to the comprehensive analysis of complex chemical systems.     

Allosteric Modulation of the CB1 Cannabinoid Receptor by Cannabidiol—A Molecular Modeling Study of the N-Terminal Domain and the Allosteric-Orthosteric Coupling

The CB₁ cannabinoid receptor (CB₁R) contains one of the longest N termini among class A G protein-coupled receptors. Mutagenesis studies suggest that the allosteric binding site of cannabidiol (CBD) involves residues from the N terminal domain. In order to study the allosteric binding of CBD to CB₁R we modeled the whole N-terminus of this receptor using the replica exchange molecular dynamics with solute tempering (REST2) approach. Then, the obtained structures of CB₁R with the N terminus were used for ligand docking. A natural cannabinoid receptor agonist, Δ⁹-THC, was docked to the orthosteric site and a negative allosteric modulator, CBD, to the allosteric site positioned between extracellular ends of helices TM1 and TM2. The molecular dynamics simulations were then performed for CB₁R with ligands: (i) CBD together with THC, and (ii) THC-only. Analyses of the differences in the residue-residue interaction patterns between those two cases allowed us to elucidate the allosteric network responsible for the modulation of the CB₁R by CBD. In addition, we identified the changes in the orthosteric binding mode of Δ⁹-THC, as well as the changes in its binding energy, caused by the CBD allosteric binding. We have also found that the presence of a complete N-terminal domain is essential for a stable binding of CBD in the allosteric site of CB₁R as well as for the allosteric-orthosteric coupling mechanism.     

基于分子指纹对黄酮类化合物及其抗DPPH自由基活性的QSAR分析

应用定量构效关系（Quantitative structure activity relationship, QSAR）研究阐明黄酮类化合物（Flavonoid compounds, FCs）的子结构指纹（Substructure fingerprint）与1,1-二苯基-2-三硝基苯肼（1,1-Diphenyl-2-picrylhydrazyl, DPPH）自由基清除能力之间的关系,从而指导高效抗氧化物质的设计和发现。在PubMed数据库中收集77个具有明确抗氧化活性的黄酮类化合物,而在ChEMBL数据库中收集86个无抗DPPH活性的黄酮类化合物。这163个黄酮类化合物的子结构指纹由PubChem系统生成,然后通过卡方检验筛选出与黄酮类化合物的抗氧化活性显著相关的分子指纹,最后通过判别分析建立预测QSAR模型,并采用回代法和交叉验证法对已建立的模型进行准确性和稳健性的验证。结果表明,黄酮类化合物抗DPPH自由基活性与ESSSR环的计数、简单相邻原子的类型和简单的SMARTS模式等因素有关。此外,所建立的QSAR模型能较好地预测黄酮类化合物的DPPH自由基清除活性,可用于评价候选抗氧化剂的潜力。     

潜指纹显现方法研究进展

综合介绍了常用的几种潜指纹显现方法及原理,其中主要综述了指纹的物理化学显现法和化学显现法的进展,包括多金属沉淀法、茚三酮法和荧光材料显现法等。     

人体尿液的三维荧光指纹图谱

采用三维荧光光谱技术获得了不同人群尿液的指纹图谱,对24个胃癌病人以及27个健康人的尿样进行了测定,并结合主成分分析的投影判别法和聚类分析法对尿样三维荧光谱的特征参数进行了模式识别研究。结果表明,病人和健康人的尿样存在一定的差异,且主成分分析投影判别法和聚类分析法均能对样品进行较好的分离识别,从而建立了识别癌症病人以及健康人的尿液的新方法。     

Self‐assembled Dynamic 3D Fingerprints in Liquid‐Crystal Coatings Towards Controllable Friction and Adhesion

Chiral‐nematic polymer network coatings form a “fingerprint” texture through self‐assembly. For this purpose the molecular helix of the coating is oriented parallel to the substrate. The coating has a flat surface but when actuated by light in the presence of a copolymerized azobenzene compound, 3D fingerprint structures appear in the coating. The helix forms protrusions at the positions where the molecules are aligned parallel to the surface and withdraws at the positions where the orientation is perpendicular. This process proceeds rapidly and is reversible, that is, the fingerprint‐shaped protrusions disappear when the light is switched off. The texture in the on‐state resembles that of a human fingerprint and is used to manipulate the gripping friction of a robotic finger. The friction coefficient drops by a factor of four to five when the fingerprint switched on because of reduced surface contacts.