A strategy for rapid structural characterization of saponins and flavonoids from the testa of Camellia oleifera Abel seeds by ultra-high-pressure liquid chromatography combined with electrospray ionization linear ion trap-orbitrap mass spectrometry

Saponins and flavonoids are the main bioactive ingredients in Camellia oleifera Abel. In this study, the fragmentation pathways of triterpene saponins in Camellia oleifera were investigated and confirmed by electrospray ionization linear ion trap-orbitrap (LTQ-orbitrap), and a new strategy for rapid characterization of saponins by ultra-high-pressure liquid chromatography with LTQ-orbitrap mass spectrometry (UHPLC-LTQ-orbitrap-MSn) was developed. Based on the summarized fragmentation rules, 36 triterpene saponins from the testa of C. oleifera extracted by n-butanol were found, 23 of which were completely and tentatively characterized. Besides, 35 saponins were identified as novel saponins. Additionally, 8 flavonol-O-glycosides were separated from C. oleifera, with 7 being tentatively characterized but one unambiguously identified, and one of the 7 flavonol-O-glycosides is reported for the first time in genus Camellia. This study provides a systematic strategy for the identification of saponins by the UPLC-MSn method in genus Camellia and summarized essential data for phytochemical studies of C. oleifera.