[Mechanism of Tibetan medicine Pterocephalus hookeri extract in treatment of rheumatoid arthritis based on serum metabonomics].

Ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF/MS) was used to investigate the effect of Pterocephalus hookeri on serum metabolism of adjuvant arthritis(AA) model rats induced by complete Freund's adjuvant. After the AA model was properly induced, the serum of rats was collected 30 days after treatment. UPLC-Q-TOF-MS chromatograms were collected and analyzed by principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). The results revealed that compared with the control group, the model group showed increased content of 12 biomarkers in the serum(P<0.05) and reduced content of the other nine biomarkers(P<0.05). P. hookeri extract could recover the above-mentioned 19 biomarkers to a certain range. Pathway enrichment showed that these markers mainly involved eight metabolic pathways, including valine, leucine, and isoleucine degradation, arachidonic acid metabolism, arginine and proline metabolism, glycerol phospholipid metabolism, primary bile acid biosynthesis, bile acid biosynthesis, tryptophan metabolism, and unsaturated fatty acid biosynthesis. The findings of this study demonstrate that P. hookeri extract can regulate metabolic disorders and promote the regression of metabolic phenotype to the normal level to exert the therapeutic effect on AA rats. This study is expected to provide a certain scientific basis for the biological research on the treatment of rheumatoid arthritis by P. hookeri.

[Qualitative analysis of illegally adulterated sildenafil and related compounds in dietary supplements by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry].

The presence of illegally adulterated sildenafil and related compounds in dietary supplements was qualitatively analyzed by employing ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Samples were extracted by ultrasonic method using methanol. The analysis was performed on an Agilent Poroshell 120 SB-C18 column (75 mm×3.0 mm, 2.7 µm) using gradient elution with a mixture of aqueous formic acid solution (0.1%, v/v) and acetonitrile as the mobile phase at a flow rate of 0.4 mL/min. Q-TOF-MS equipped with ESI ion source was operated in a positive ionization mode. Qualitative analysis was based on the retention time and the accurate relative molecular mass of elemental compositions of the precursor ion and product ions. The limits of detection (LODs) of sildenafil and other 99 compounds were found to be 0.1-50 mg/kg or 0.1~50 mg/L in 10 different matrices. In this manuscript, the fragmentation behavior of 98 phosphodiesterase-5 inhibitors are categorically summarized, which can provide information for referencing and identification of suspicious compounds. The method was successfully applied to the analysis of actual samples, of which 19 compounds combated the illegal adulteration behavior effectively.