Measurement of pharmacokinetics and tissue distribution of three bioactive constituents from Zanthoxylum armatum DC in rat plasma and tissues through UFLC-MS/MS

The compounds of N-Methylanhydrotetrahydroberberrubine A, dictamnine and eudesmin were the primary bioactive components in the roots of Zanthoxylum armatum DC (Z. armatum). To clarify the pharmacokinetics and distribution of these three compounds, an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was employed to determine the contents of these three compounds in rat plasma and seven tissues. The separation was achieved on a Kinetex XB-C18 100A column (2.1 × 50 mm, 2.6 μm, Phenomenex). The optimized mobile phase system was set with 0.1‰ formic acid aqueous solution (A) and acetonitrile (containing 0.1‰ formic acid) (B) with a programmed elution of 0.00 to 0.50 min, 2% B; 0.51-4.00 min, 30%-60% B; and 4.01-5.00 min, 2% B. All analytes were measured with optimized multiple reaction monitoring (MRM) in the positive ion ESI mode. Berberine hydrochloride was selected as the internal standard (IS). The MS/MS transitions of N-Methylanhydrotetrahydroberberrubine A, dictamnine, eudesmin and IS were 339.9135.1, 200.1 → 129.1, 387.4 → 369.0 and 337.1 → 321.1, respectively. The lower limits quantification (LLOQ) of the three analytes was 0.5-20 ng/ml. The linear ranges were 0.5-400 ng/ml for N-Methylanhydrotetrahydroberberrubine A and dictamnine and 20-4000 ng/ml for eudesmin. The present analysis showed that the two alkaloids were quickly absorbed, with Tmax in 0.167-0.292 h, and eudesmin was absorbed in 2.5 h. Moreover, all compounds were found at high concentrations in the gastrointestinal track. These results are helpful for further investigation of the clinical application of Z. armatum.