LC-high-resolution-MS/MS analysis of chemical compounds in rat plasma after oral administration of Nao-Mai-Tong and its individual herbs

Nao-Mai-Tong (NMT), a Chinese herbal formula, is used for treating ischemia cerebral apoplexy. To discover the components of NMT with potential in vivo bioactivity and investigate the differences between NMT and its single herb components, this study rigorously compared plasma samples collected from rats dosed with NMT and single-herb extracts at different times through LC-high resolution-MS/MS and data processing (Metworks). The plasma of the NMT group contained a total of 66 identified compounds (25 prototypes and 41 metabolites), including anthraquinones, triterpenoid saponins, isoflavones and phthalides. Additionally, glucuronidation, sulfation and cysteine conjugation were the major reactions through which the compounds in NMT were metabolized. The comparison of the groups revealed two metabolites that were only detected in the plasma from the NMT-dosed group, whereas seven prototype ingredients (chrysophanol-8-O-glucoside, ginsenoside Rf, Rg2, Rh1, F1, F2 and chikusetsusaponin IVa) and 12 metabolites (two novel triterpenoid saponins) were only discovered in the plasma samples from the single-herb-dosed groups. Moreover, the trends in the chemical compounds detected presented marked differences between NMT-dosed rat plasma and plasma samples from the single-herb-dosed groups. The above data indicate that prescription compatibility affects the assimilation and elimination of ingredients and provides useful information for further pharmacokinetic studies.