Validated LC-MS/MS method for quantitation of demethylbellidifolin in rat plasma and its application to pharmacokinetic and bioavailability studies.

Demethylbellidifolin, a major xanthone compound of Swertia davidi Franch, shows many beneficial pharmacological effects including antioxidation, anti-inflammation, anti-fibrosis and cardiovascular protection effects. In this research, a rapid and sensitive LC-MS/MS method for the quantitative analysis of demethylbellidifolin in rat plasma was developed. The demethylbellidifolin and internal standard of aurantio-obtusin were extracted from 50 μL of rat plasma samples with ethyl acetate, then the dried residue was reconstituted and injected in an HPLC system with Zorbax SB-C18 analytical column (2.1 × 100 mm, 3.5 μm) and eluted with the mobile phase consisting of methanol and 0.2% formic acid aqueous solution (80:20, v/v). Quantification was performed using a TSQ Quantum Ultra mass spectrometer in negative ESI using selected reaction monitoring mode of the transitions m/z 259.1 → 215.1 for demethylbellidifolin and 329.0 → 314.2 for the IS. Excellent linearity was observed between 1.92 and 960 ng/mL with a limit of quantitation of 1.92 ng/mL. Intra- and inter-day precision (RSD) values of quality control samples were both <8.3%. This study was successfully utilized for the pharmacokinetic profiles of demethylbellidifolin in rats after oral or intravenous administration. The oral bioavailability of demethylbellidifolin was 3.6%.