Metabolites characterization of timosaponin AIII in vivo and in vitro by using liquid chromatography-mass spectrometry

Timosaponin AIII, a major saponin found in Anemarrhena asphodeloides Bge., exhibits a wide spectrum of bioactivities. It is believed that it may be further developed into a promising new drug. To better understand the pharmacological activities of the component, the investigation of its in vivo and in vitro metabolism was necessary. In this study, the metabolic profile of timosaponin AIII was investigated using liquid chromatography-mass spectrometric (LC/MS) techniques. Two different types of mass spectrometers-aquadrupole time-of-flight (Q-TOF) mass spectrometer and hybrid quadrupole/linear ion trap (Q-TRAP) mass spectrometer were employed to acquire structural information on timosaponin AIII metabolites. Plasma, bile, urine and feces were collected from rats after a single oral dose of 400mg/kg of water solution. A total of 19 metabolites were detected and tentatively identified based on the mass spectral fragmentation patterns, elution order or confirmed using available reference standard. Two metabolites were detected after incubating with rat liver microsomal. What's more, we isolated sarsasapogenin from the collection of urine samples after timosaponin AIII (5.0g) giving orally to 20 rats at a dose of 150.0mg/kg in an interval of 7 days. The present study provided important information about the metabolism of timosaponin AIII which will be helpful for fully understanding the mechanism of this compound's action.