Characterization and simultaneous quantification of seven triterpenoid saponins in different parts of Xanthoceras sorbifolia Bunge by HPLC-ESI-TOF

Abstract

In order to find new candidates against Alzheimer's disease, two new triterpenoid saponins, sorbifoside C (1) and D (4), and five known triterpenoid saponins (2, 3, and 5–7) were isolated and identified from the husks of Xanthoceras sorbifolia Bunge. Their structures were elucidated through 1D, 2D NMR and HR-MS. A fast, sensitive and reliable high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) method has been developed and validated to simultaneously quantitate the content of seven triterpenoid saponins in different parts of X. sorbifolia. The quantification was accomplished on a triple quadrupole tandem mass spectrometer in the selected ion monitoring and positive ionization modes. Good chromatographic separation was achieved by gradient elution with the mobile phase consisting of acetonitrile and 0.05% formic acid in water during a total run time of 20 min. All of the seven compounds showed good linearity (r² > 0.998) in relatively wide concentration ranges. Satisfactory precisions (evaluated by intra- and inter-day tests) and recoveries/accuracies (98.0% to 102.0%) were obtained with RSD values less than 3.0%. The method was successfully adapted for simultaneous quantification of the seven analytes in different parts of X. sorbifolia. The results showed that triterpenoid saponin contents from different parts of the plant varied significantly and a reference for the choice of medicinal parts was accordingly provided.