Pharmacokinetics and bioavailability of gentiopicroside from decoctions of Gentianae and Longdan Xiegan Tang after oral administration in rats — Comparison with gentiopicroside alone

Abstract

The pharmacokinetics and bioavailability of gentiopicroside (GPS), an active component of the Gentian plant species, from orally administered decoctions of <i>Gentianae</i> (DG), or in combination with other plants in the prescription of <i>Longdan Xiegan Tang</i> (LXT), was compared in rats with oral administration of GPS alone, using doses adjusted to deliver equivalent amounts of GPS (150 mg/kg). Changes in plasma levels of GPS following oral administration of GPS or DG could be fitted to a one compartment open model with elimination half times (T_(1/2)K_e) of 3.35 ± 0.76 h and 6.21 ± 3.07 h, respectively. Kinetics of plasma GPS following oral administration of LXT could be fitted to a two compartments open model with an elimination half time (T_(1/2)β) of 3.83 ± 1.54 h. The bioavailability of GPS from DG was markedly better, and that from LXT markedly worse, compared with GPS alone, as judged by the area under concentration-time curve (AUC) values of 70.0 ± 13.9 μg h/ml (DG), 32.7 ± 12.9 μg h/ml (GPS) and 19.1 ± 5.9 μg h/ml (LXT). The study demonstrates the marked variability in pharmacokinetics and bioavailability of an active component from different herbal preparations.