Pharmacokinetic study and metabolite identification of the bidesmosidic triterpenoid saponin BTS-1 in rat plasma

Assays based on high-performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LC-MSn) have been developed and validated for the determination and metabolite identification of the bidesmosidic triterpenoid saponin, BTS-1 (3-O-beta-D-galactopyranosyl-(1 -> 2)-[beta-D-xylopyranosyl-(1 -> 3)]-beta-D-glucuronopyranosyl gypsogenin28-O-alpha-L-arabinopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-fucopyranoside), in rat plasma. The assay was successfully applied to a pharmacokinetic study in rats given a single oral dose of BTS-1 (400 mg/kg). The results indicated that the compound was rapidly absorbed (T-max = 1.28 +/- 0.29 h, C-max = 37.4 +/- 5.6 mu g/mL) and slowly eliminated (t(1/2)= 13.2 +/- 6.6 h). In addition, secondary glycosides and aglycones of BTS-1 were detected and identified. Since these metabolites are known to be active a-glucosidase inhibitors, they probably play an important role in mediating the pharmacological effects of the saponin. (C) 2013 Institute of Materia Medica, Chinese Academy of Medical Sciences and Chinese Pharmaceutical Association. Production and hosting by Elsevier B.V. All rights reserved.