Cloning and analysis of the DXR gene and its promoter in Morinda officinalis / 药学学报

The objective of this research was to clone 1-deoxy-D-xylulose 5-phosphate reductoisomerase gene (MoDXR) and its promoter sequence from Morinda officinalis and carry out bioinformatic analysis, cis-acting elements analysis, and prokaryotic expression. On the basis of the MoDXR gene sequence obtained from the M. officinalis transcriptome and with NCBI-ORFfinder analysis, a pair of specific primers were designed, and used for RT-PCR amplification. The promoter region sequence at the 5′ end of MoDXR gene was isolated by the genome walking technique. Localization of MoDXR was carried out by subcellular analysis. The prokaryotic expression plasmid pET-28a-MoDXR was constructed and transfected into Escherichia coli BL21(DE3) chemically-competent cells; the recombiant plasmid expressed fusion protein after the induction by IPTG. The full-length cDNA of MoDXR was 2 015 bp,and open reading frame (ORF) size was 1 425 bp, and it encoded 474 amino acid residues and had a molecular mass of 51.27 kD. Sequence comparison with BlastP to the NCBI database revealed that MoDXR had high sequence similarity with many other DXRs, such as Coffea arabica DXR (CaDXR) and Rauvolfia verticillata DXR (RvDXR). A phylogenetic tree revealed that MoDXR had its closest relationship with DXR from Coffea arabica and Gardenia jasminoides. The subcellular localization revealed that MoDXR protein was located on the chloroplast. Plantcare analysis indicated that the promoter region sequence of MoDXR was 1 493 bp, covering multiple light, stress, and hormone-responsive cis-regulatory elements; protein electrophoresis showed that the expressed protein was the anticipated size. This research lays the foundation for further purification and structural and functional characterization of the MoDXR protein.

Material for evaluation of notoginseng total saponin preparation induced pseudoanaphylactoid reactions / 中国中药杂志

The experiment is designed to explore pathological festures and material basis of pseadoanaphylactoid reaction induced by notoginseng total saponin preparation. Mouse pseadoanaphylactoid reaction was used, 50 ICR mice were randomly assigned to control group, positive medicine group, notoginseng total saponin preparation low-dose group, notoginseng total saponin preparation middle-dose group, notoginseng total saponin preparation high-dose group on average. They are treated by intravenous injection of test substance solutions containing 0.4% Evans blue (EB). 30 min later, scores of ear blue staining and quantitation of ear EB exudation were recorded. Another two experiment were repeated in the same way excluding EB, just to. detect the related cytokines in serum using ELISA. We found that the scores of pseudoanaphylactoid reaction in notoginseng total saponin preparation injection middle-dose group and high-dose group was evidently higher than that in control group, suggesting that notoginseng total saponin preparation injection may be can lead to pseadoanaphylactoid reaction. HE staining showed that pseadoanaphylactoid reaction induced by notoginseng total saponin preparation injection is related to inflammation. Histamine, VEGF and TNF-α levels in notoginseng total saponin preparation middle-dose group and high-dose group significantly increased (P < 0.05, P < 0.01) than control group and showed a dose-dependent manner as well as consistent with the degree of ear blue dye. While IL-6 and IL-10 content did not increase significantly in notoginseng total saponin preparation low-dose group and middle-dose group, but they significantly higher than control group (P < 0.05, P < 0.01) when it increased to quadrupe clinical concentrations, eight times of the clinical dose. So pseadoanaphylactoid reaction caused by notoginseng total saponin preparation may be related to histamine, VEGF, TNF-α, and it is possible that IL-6 and IL-10 can play a role when pseadoanaphylactoid reaction achieve a certain high degree.

Preliminary study on hepatotoxicity induced by dioscin and its possible mechanism / 中国中药杂志

Dioscin has a wide range of biological effects and broad application prospects. However the studies concerning the toxicology and mechanism of dioscin is small. This article is to study the hepatotoxicity of dioscin and the effect of dioscin treatment on expression of aryl hydrocarbon receptor (AhR) mRNA and CYP1A mRNA and protein in HepG2 cells in vitro. Dioscin 0.5-32 µmol · L(-1) exposed to HepG2 cells for 12 h, cell viability was examined by CCK-8 assay and the release rate of lactate dehydrogenase (LDH) was to evaluate cell membrane damage. HepG2 cells morphologic changes were quantified by inverted Microscope, and the effect on production of reactive oxygen species (ROS) was detected by flow cytometry. The mRNA expression of CYP1A and AhR was evaluated by RT-RCR. The protein expression of CYP1A1 was detected by western blot. The cell viability was significantly inhibited after HepG2 cells were exposed to dioscin 0.5-32 µmol · L(-1). Compared with the control, the LDH release rate and ROS were significantly increased. The expression of CYPlA and AhR mRNA was increased. The expression of CYP1Al protein was increased after dioscin treatment, and resveratrol, an AhR antagonist, could downregulate the expression of CYP1A1. It follows that large doses dioscin has potential hepatotoxicity. The possible mechanism may be dioscin can active aryl hydrocarbon receptor (AhR) and induce the expression of CYP1A.

Pharmacology research on PXR as a potential target in screening bioactive components of Chinese material medica / 中国中药杂志

Pregnane X receptor (PXR) is key transcription factors which mainly regulate the expression of CYP3A genes. At the molecular level, PXR has been revealed the protection mechanism of the body against xenochemicals and a major mode of the drug-drug interactions. Besides playing an important role in drug metabolism and interactions, PXR and its target genes also play an important role in maintaining normal physiological function and homeostasis. Therefore, it is necessary to study the regulation of PXR and its related pharmacological effects of TCM and natural products, and to provide new clues for the new pharmacological pathway.