Study on steroidal saponins in crude and stir-fried Fructus Tribuli by ultra-high-performance liquid chromatography-mass spectrometry coupled with multivariate statistical analysis

Fructus Tribuli is a traditional Chinese medicine used clinically for many years. Crude Fructus Tribuli and stir-fried Fructus Tribuli are recorded in the Pharmacopoeia of the People's Republic of China. However, the differences between steroidal saponins in crude Fructus Tribuli and stir-fried Fructus Tribuli have not been compared. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry along with multivariate statistical analysis was developed to discriminate the chemical profiles and identify the steroidal saponins of crude Fructus Tribuli and stir-fried Fructus Tribuli. Additionally, an ultra-high-performance liquid chromatography triple-quadrupole mass spectrometer was used for the simultaneous quantification of nine major steroidal saponins to analyze the variations between crude Fructus Tribuli and stir-fried Fructus Tribuli. Finally, a total of 30 steroidal saponins whose structures or contents changed significantly after processing were found and identified. The mechanism of structural transformations deduced indicated that during the stir-frying of Fructus Tribuli, C-22 hydroxy furostanol saponins were converted to the corresponding furostanol saponins containing C-20-C-22 double bonds by dehydroxylation and deglycosylation reactions that occurred in the spirostanol saponins causing the generation of steroidal sapogenins. This study was successfully applied to the global analysis of crude Fructus Tribuli and stir-fried Fructus Tribuli. The results of this research will be beneficial to explore the processing mechanism of Fructus Tribuli.