Identification of flavonol and triterpene glycosides in Luo-Han-Guo extract using ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry

In this study, a method for the identification of flavonol and triterpene glycosides in Luo-Han-Guo extract using ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS) with personal database matching has been developed. Two flavonol glycosides and 20 triterpene glycosides were identified, and in addition the profiles of Luo-Han-Guo samples collected at different growing periods (15-, 40-, and 80-days) were compared. Principle component analysis (PCA) showed a clear separation among the various samples from different growing periods. The content of mogroside V significantly increased, while the level of mogroside IIE class dramatically decreased with an increase of growing time; however, the content of mogroside IV class was found to be high after a 40-day period of accumulation, but it subsequently decreased in the fully ripe period. Finally, 7 mogrosides could be screened as potential markers for discrimination of Luo-Han-Guo samples at different stages. The proposed analytical method combined with multivariate statistical analysis was shown to be a useful tool for investigating the chemical components of Luo-Han-Guo as well as for its quality evaluation.