RESUMEN
OBJECTIVE: To establish a method for simultaneous quantitative determination of 14 bile acids in human plasma by liquid chromatograohy-tandem mass spectrometry (LC-MS/MS) and to explore the correlation between the hepatotoxicity induced by cyclosporine A and bile acids. METHODS: Plasma samples were extracted by protein precipitation and bile acids were separated on a Waters ACQUITY UPLC HSS T3(2.1 mm×150 mm,1.8 μm) column with a flow rate of 0.3 mL•min-1. The mobile phase was water (containing 4 mmol•L-1 ammonium acetate) and 95% acetonitrile using gradient elution in 15 min. The detection system used an electrospray ion source in negative ion mode. RESULTS: Fourteen bile acids had a good linear relationship, the intra-and inter-assay RSD values were less than 15%, the accuracy was between 87% and 116%, and the extraction recovery rates of the quality was between 101% and 120%. The concentration of cholic acid (CA) was well correlated with cyclosporine A and suggested that bile acids may be associated with the hepatotoxicity induced by cyclosporine A. CONCLUSION: This LC-MS/MS method for quantitatively determining various bile acids in human plasma is convenient, accurate and sensitive and can be used for further basic research in hepatotoxicity caused by cyclosporine A.
RESUMEN
Objective: To study the anti-influenza A virus effect of theaflavin derivatives which contain theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B), and theaflavin-3, 3'-digallate (TF3) and to investigate the mechanism. Methods: The inhibition of theaflavin derivatives on A/Thailand/Kan353/2004 H5N1 pseudovirus was investigated using pseudotype H5N1 virus system. Hemagglutination inhibition assay and neuraminidase (NA) inhibition assay were used to investigate the mechanism for their anti-influenza activities. The inhibition of theaflavin derivatives on influenza A virus FM_1 was observed by H1N1 FM_1 system. Cytotoxicity of theaflavin derivatives on MDCK cells was determined by MTT assay. Results: Theaflavin derivatives could significantly inhibit the infection of pseudovirus H5N1 with IC50 of (151.88 ± 18.95) μg/mL. It had no inhibition on HA1 subunit. Theaflavin derivatives had the inhibition on NA with IC50 of (129.09 ± 1.33) μg/mL. Theaflavin derivatives showed a significant inhibitory activity on FM_1 influenza virus strain in MDCK cells. Theaflavin derivatives showed the low cytotoxicity on MDCK cells with CC50 of (879.89 ± 4.54) μg/mL. Conclusion: Theaflavin derivatives could inhibit the infection of avian influenza virus through the combination with hemagglutinin (HA) HA2 subunit and inhibit the activity of viral NA to some extent, which indicates that the anti-H5N1 avian influenza virus of theaflavin derivatives may be through multi-targets.