Application of liquid chromatography/electrospray ionization mass spectrometry for bio-analysis and for drug metabolism and pharmacokinetic study of ginsenosides from ginseng

This work focuses on the application of liquid chromatography-electrospray ionization mass spectrometry in bio-analysis and for drug metabolism and pharmacokinetic of ginsenosides from ginseng.; Qualitative and quantitative analyses of AMP, ADP and ATP in cellular samples have been investigated by using the developed ion-pairing liquid chromatography coupled with electro-spray mass spectrometry (LC-ESI-MS) method. The use of N, N-dimethylhexylamine (DMHA) as the ion-pairing agent enabled the retention and separation of these polar compounds on the reversed-phase HPLC column and the detection of their adduct ions with DMHA by using positive ion mode of ESI-MS. Adduct ions of the nucleotide and the ion-pairing agent DMHA were selected as quantitative ions because their peaks were more intensive than those of intact protonated molecular ions. Linear calibration curves were obtained for AMP with a concentration range of 0.1-20 muM (y=1607x-84, R 2=0.9992), for ADP at 2-20 muM (y=3174x-5889, R2=0.9994), and for ATP at 2.5-20 muM (y=411x-997, R2=0.9991), respectively, where y is the peak area and x is the concentration (muM) of the nucleotide. The limits of detection were 0.17 ng for AMP, 4.27 ng for ADP and 6.34 ng for ATP per on-column injection with an injection volume of 5mu1. The method has been applied to determine AMP, ADP and ATP concentration levels in biological samples of rat brain cells that were pre-treated with different Zn concentrations to support investigation of Zn's effects to the cell energy metabolism.; Liquid chromatography coupled with mass spectrometry (LC-MS) and tandem mass spectrometry (MS-MS) have been applied to investigate pharmacokinetics and metabolism of ginsenoside Rb1, Rg3 and Rh2 .; Pharmacokinetic study of Rg3 on rat showed short half-life (18.5 min). No Rg3 and its possible metabolites were detected from the rat urine collected from 0 to 24 hours after intravenous and oral administration. Six metabolites of Rg3 were detected from feces collected between 0-24 hours after oral administration by LC-MS and confirmed by MS-MS analyses. (Abstract shortened by UMI)...