Chemical markers for the quality control of herbal medicines: an overview

Selection of chemical markers is crucial for the quality control of herbal medicines, including authentication of genuine species, harvesting the best quality raw materials, evaluation of post-harvesting handling, assessment of intermediates and finished products, and detection of harmful or toxic ingredients. Ideal chemical markers should be the therapeutic components of herbal medicines. However, for most herbal medicines, the therapeutic components have not been fully elucidated or easily monitored. Bioactive, characteristic, main, synergistic, correlative, toxic and general components may be selected. This article reviews the effective use of chemical markers in the quality control of herbal medicines including the selection criteria considering the roles and physicochemical factors which may affect the effective use of chemical markers

Analysis of the transcriptome of Panax notoginseng root uncovers putative triterpene saponin-biosynthetic genes and genetic markers

<p>Abstract</p> <p>Background</p> <p><it>Panax notoginseng </it>(Burk) F.H. Chen is important medicinal plant of the <it>Araliacease </it>family. Triterpene saponins are the bioactive constituents in <it>P. notoginseng</it>. However, available genomic information regarding this plant is limited. Moreover, details of triterpene saponin biosynthesis in the <it>Panax </it>species are largely unknown.</p> <p>Results</p> <p>Using the 454 pyrosequencing technology, a one-quarter GS FLX titanium run resulted in 188,185 reads with an average length of 410 bases for <it>P. notoginseng </it>root. These reads were processed and assembled by 454 GS <it>De Novo </it>Assembler software into 30,852 unique sequences. A total of 70.2% of unique sequences were annotated by Basic Local Alignment Search Tool (BLAST) similarity searches against public sequence databases. The Kyoto Encyclopedia of Genes and Genomes (KEGG) assignment discovered 41 unique sequences representing 11 genes involved in triterpene saponin backbone biosynthesis in the 454-EST dataset. In particular, the transcript encoding dammarenediol synthase (DS), which is the first committed enzyme in the biosynthetic pathway of major triterpene saponins, is highly expressed in the root of four-year-old <it>P. notoginseng</it>. It is worth emphasizing that the candidate cytochrome P450 (Pn02132 and Pn00158) and UDP-glycosyltransferase (Pn00082) gene most likely to be involved in hydroxylation or glycosylation of aglycones for triterpene saponin biosynthesis were discovered from 174 cytochrome P450s and 242 glycosyltransferases by phylogenetic analysis, respectively. Putative transcription factors were detected in 906 unique sequences, including Myb, homeobox, WRKY, basic helix-loop-helix (bHLH), and other family proteins. Additionally, a total of 2,772 simple sequence repeat (SSR) were identified from 2,361 unique sequences, of which, di-nucleotide motifs were the most abundant motif.</p> <p>Conclusion</p> <p>This study is the first to present a large-scale EST dataset for <it>P. notoginseng </it>root acquired by next-generation sequencing (NGS) technology. The candidate genes involved in triterpene saponin biosynthesis, including the putative CYP450s and UGTs, were obtained in this study. Additionally, the identification of SSRs provided plenty of genetic makers for molecular breeding and genetics applications in this species. These data will provide information on gene discovery, transcriptional regulation and marker-assisted selection for <it>P. notoginseng</it>. The dataset establishes an important foundation for the study with the purpose of ensuring adequate drug resources for this species.</p

An Improved Current-Doubler Rectifier for the Marine Controlled Source Electromagnetic Transmitter

High power marine controlled source electromagnetic transmitters have gained interest with applications in marine geological survey and mineral resources exploration. The direct current to direct current (DC-DC) converter that is typically used in marine transmitters has some issues, as the insulated-gate bipolar transistor (IGBT) tube cannot achieve zero-voltage switching (ZVS). In particular, lagging-leg switching cannot easily achieve ZVS. The conversion efficiency of the heat converter requires improvement. This paper proposes an improved current-doubler rectifier for the marine controlled source electromagnetic transmitter (ICDR-MCSET). Resonant inductance is increased and a blocking capacitor is added to the converter (DC-DC) circuit, where the converter can achieve ZVS in a wide load range. This results in the effective decrease of the heating temperature and the improvement of transformation efficiency. Saber software simulation and a 20 KW electromagnetic transmitter are used to verify the results, which show that the method is feasible and effective

Tackling Inflammatory Bowel Diseases: Targeting Proinflammatory Cytokines and Lymphocyte Homing

Inflammatory bowel diseases (IBDs) are characterized by chronic inflammatory disorders that are a result of an abnormal immune response mediated by a cytokine storm and immune cell infiltration. Proinflammatory cytokine therapeutic agents, represented by TNF inhibitors, have developed rapidly over recent years and are promising options for treating IBD. Antagonizing interleukins, interferons, and Janus kinases have demonstrated their respective advantages in clinical trials and are candidates for anti-TNF therapeutic failure. Furthermore, the blockade of lymphocyte homing contributes to the excessive immune response in colitis and ameliorates inflammation and tissue damage. Factors such as integrins, selectins, and chemokines jointly coordinate the accumulation of immune cells in inflammatory regions. This review assembles the major targets and agents currently targeting proinflammatory cytokines and lymphatic trafficking to facilitate subsequent drug development

An Efficient Approach to Pyrene-based Aggregation-induced Emission Luminogens

To suppress the fluorescence quenching of pyrene in the aggregation state, this article presents a facile strategy for the construction of pyrene-based aggregation-induced emission luminogens (AIEgens) via decorating the pyrene core with benzophenone units at the 1-, 2- or 2,7-positions. This set of pyrene-based compounds 1–3 displayed a weak deep blue fluorescence in solution, but an enhanced excimer emission with λem max of 426–436 nm in the aggregation state. Interestingly, unlike reported benzophenone derivatives, this series of compounds did not exhibit thermally activated delayed fluorescence/ phosphorescent properties

Experimental and theoretical studies of the effect of molecular conformation on the photophysical properties in the pyrene system

Disordered motion is an intrinsic property of molecules. The use of controllable molecular motion can not only achieve interesting molecular geometry, but can also induce novel opto-electronic behaviour. Herein, a set of pyrene-based compounds were synthesized to realize an observable molecular motion. 2,5-Dimethoxyphenyl unit (s) were introduced at the pyrene core, which lead to different molecular conformations. Furthermore, the detail molecular geometries of the compounds were investigated by NMR spectroscopy and DFT calculations. In addition, the photophysical properties of these compounds were investigated in order to understand the relationship between the molecular conformations and the photophysical properties. The diversiform of molecular conformations can cause a broaden FWHM emission in organic luminescence materials