Effect of heavy metal lead on anticoagulant activity of leech based on label-free quantitative proteomics / 中国中药杂志

Whitmania pigra is the most widely distributed species of leeches in the market. In this study, the effect of heavy metal lead pollution on the anticoagulant activity of Wh. pigra was studied and the potential mechanism was explored. Pb(NO_3)_2 was used to contaminate the breeding soil which was then used to rear Wh. pigra for 50 days(lead-contaminated group, LC group), and meanwhile the blank control group(CG group) was set. Proteins were extracted from the obtained leech samples, and the differentially expressed proteins between LC and CG groups were analyzed by label-free proteomics technology. In this study, a total of 152 differentially expressed proteins were screened out, of which 93 proteins were up-regulated and 59 proteins were down-regulated in LC group. Bioinformatics analysis showed that the biological processes enriched with the differentially expressed proteins were mainly vesicle-mediated transport and transport positive regulation; the enriched cell components were mainly endocytosis vesicles and apical plasma membrane; the enriched molecular functions mainly included carbohydrate binding. The differentially expressed proteins were enriched in 76 KEGG pathways, which mainly involved metabolic pathways, biosynthesis of secondary metabolites, and bacterial invasion of epithelial cells. In this study, two differentially expressed proteins with Antistasin domain were presumed, which provides reference for further exploring the regulatory mechanism and signal transduction underlying the effect of lead pollution on the anticoagulant activity of leech.

Determination of caffeine content in Ginkgo Folium by ultra high performance liquid chromatography-triple quadrupole mass spectrometry / 中国中药杂志

In this experiment, an ultra-high performance liquid chromatographytandem triple quadrupole mass spectrometry was established for the determination of caffeine in commercially available Ginkgo Folium. The samples were extracted by ultrasonic method with methanol, and separated on Waters CORTECS T3 column(2.1 mm×100 mm, 2.7 μm), with mobile phase of 0.1% formic acid solution-0.1% formic acid acetonitrile solution for gradient elution, at flow rate of 0.3 mL·min~(-1); column temperature of 30 ℃, and injection volume of 2 μL. Mass spectrometry was conducted at ESI~+ multiple reaction monitoring(MRM) mode; quantitative analysis was conducted with external standard method. The results showed that in the range of 0.099 6-9.96 ng·mL~(-1), there was a good linear relationship between the mass concentration of caffeine and the peak area, R~2=0.999; the average recovery was 84.51%, with RSD of 6.2%. The results of precision, repeatability and stability showed that the RSD was 5.1%, 5.9%, 7.2%, respectively. The content range of caffeine in 10 batches of Ginkgo Folium was 1.52-60.86 μg·kg~(-1). In conclusion, this method is accurate, reliable and reproducible, which provides a reference for the safety study of Ginkgo Folium.