Identification of chemical constituents in Zhachong Shisanwei Pills by UPLC-Q-TOF-MS/MS / 中国中药杂志

Zhachong Shisanwei Pills, composed of 13 Chinese medicinal materials, are used for treating the diseases such as hemiplegia, pain of muscles and bones, rheumatism, and joint pain. The chemical composition and pharmacodynamics of Zhachong Shisanwei Pills have not been reported. Ultra-performance liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry(UPLC-Q-TOF-MS/MS) was employed to quickly identify the chemical components of Zhachong Shisanwei Pills, which was performed with Shim-pack GIST C_(18) column(4.6 mm×150 mm, 5 μm). The gradient elution was conducted with methanol-0.05% acetic acid as the mobile phase. Electrospray ionization mass spectrometry(ESI-MS) was carried out in both positive and negative ion modes. The compounds were identidied based on accurate relative molecular weight, fragment ion species, and the MS data of reference substances and in literature. In conclusion, a total of 98 compounds were identified, including 19 organic acids, 36 flavonoids, 13 volatile oils, 8 tannins, 5 2-(2-phenylethyl)chromones, 5 amino acids, 3 sesquiterpenoids, 3 alkaloids, and 2 other compounds. This study characte-rized the chemical components of Zhachong Shisanwei Pills rapidly for the first time, laying a foundation for further research on the pharmacodynamic material basis and quality evaluation.

Investigation of the metabolites of five major constituents from Berberis amurensis in normal and pseudo germ-free rats / 中国天然药物

Berberis amurensis (Berberidaceae) is a traditional Chinese medicine, which is often used to treat hypertension, inflammation, dysentery and enteritis. It contains alkaloids, mainly including berberine, berbamine, magnoflorine, jatrorrhizine and palmatine. Berberis amurensis extracts (BAEs) is often orally taken. Oral herbs might be metabolized by intestinal bacteria in the small intestine. However, the interaction between the herb and the gut microbiota is still unknown. In the current study, UPLC/Q-TOF-MS/MS combined with Metabolitepilot and Peakview software was used to identify the metabolites of BAEs in anti-biotic cocktail induced pseudo germ-free rats and normal rats. As a result, a total of 46 metabolites in normal rats were detected and its main metabolic pathways include demethylation, dehydrogenation, methylation, hydroxylation, sulfation and glucuronidation. Only 29 metabolites existed in pseudo germ-free rats. Dehydrogenated metabolites (M29, M30, M34 and M36), methylated metabolites (M33, M41 and M46) and other metabolites were not detected in pseudo germ-free rats. The result implied that the intestinal bacteria have an influence on the metabolism of BAEs. Furthermore, this investigation might contribute to the understanding of the metabolism of BAEs, and further promote its clinical application.

Determination of obeticholic acid in rat plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) / 药学学报

A simple and sensitive method was developed for quantitation of obeticholic acid in rat plasma with liquid chromatography-tandem mass spectrometry (LC-MS/MS). After liquid-liquid extraction by methyl tert-butyl ether, the chromatographic separation was carried out on an ACE Excel 2 Super C18 column (50 mm×2.1 mm ID, 1.7 μm) with a gradient mobile phase consisting of acetonitrile and 2 mmol·L-1 ammonium formate at a flow rate of 0.2 mL·min-1. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 418.9[M-H]-→401.2 for obeticholic acid and m/z 469.0[M-H]-→ 425.2 for glycyrrhetinic acid (internal standard) in the negative ion mode with electrospray ionization (ESI) source. This validated LC-MS/MS method yielded a good linearity over the range of 5 -5 000 ng·mL-1 with the lower limit of quantitation (LLOQ) of 5 ng·mL-1. The intra and inter-assay precisions (RSD) were all less than 9.82% and the accuracy (RE) was within ±6.90%. The extraction recovery of obeticholic acid was from 85.4% to 88.5%, and the matrix effect of obeticholic acid ranged from 78.9% to 82.5%. Stability test suggest that obeticholic acid in rat plasma was stable for 24 h on workbench, up to 1 month at -70℃, and after three cycles of freeze-thaw. Extracted samples were stable for more than 24 h in an auto-sampler at 6℃. The precision was less than 7.25%, and the accuracy was within ±11.2%, after being diluted 10 times by blank rat plasma. The method has been successfully applied to a pharmacokinetic study of obeticholic acid in rats following oral administration at the dose of 2.5 mg·kg-1.