Characterization and quantification of the triterpenoids in different parts of Xanthoceras sorbifolia by HPLC-ESI-MS.

Two new triterpenoid glycosides, sorbifoside A (2) and B (3), were isolated from the husks of Xanthoceras sorbifolia along with two known saponins (1, 5). Their structures were established on the basis of 1D and 2D NMR data. A simple and sensitive assay was developed for the simultaneous determination of 6 triterpenoids (1-6, including two triterpenoid aglycones) in X. sorbifolia based on high performance liquid chromatography-mass spectrometry (HPLC-MS) coupled to an electrospray ionization (ESI) interface. The analytes were detected by positive ESI ionization mode and quantified by selected ion monitoring (SIM). All the linear regressions were acquired with r2>0.998. The precisions were evaluated by intra- and inter-day tests, and the relative standard deviation (RSD) values were within the range of 2.0-2.8% and 1.7-2.9%, respectively. The recoveries for the quantified compounds were observed over the range of 95.3-104.7% with RSD values less than 4.6%. The method developed was successfully applied for simultaneous quantification of the six triterpenoids in X. sorbifolia, and our results showed that the contents of triterpenoids in different parts of X. sorbifolia varied significantly.