Profiling and characterization of the chemical components in Gynostemma burmanicum based on UHPLC-Q-TOF-MS technology

The genus Gynostemma, with abundant plant resources, is widely distributed in China. Gynostemma plants have gathered widespread attention both domestically and internationally due to their abundant contents of diverse dammarane triterpenoid saponins and various promising pharmacological activities. At present, the studies on the chemical constituents and pharmacological activities of Gynostemma plants mainly focus on G. pentaphyllum (Thunb.) Makino and G. longipes C. Y. Wu ex C. Y. Wu & S. K. Chen, with less attention given to other species within genus. In this study, the chemical constituents of G. burmanicum King ex Chakrav were systematically identified by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS). Firstly, the LC-MS analysis of G. burmanicum from different sources was carried out to evaluate the consistency. According to the mass spectrometry fragmentation pattern of dammarane triterpenoid saponins from Gynostemma, the fragmentation characteristics of malonylated and acetylated saponins, combined with the self-built database and online database such as ChemSipder, SciFinder, PubChem, the chemical components of G. burmanicum were identified. The similarities and differences in the components between G. burmanicum and G. longipes were further assessed by comparing their base peak chromatogram. The experimental results indicated a good consistency in the composition of G. burmanicum samples from different sources. A total of 47 chemical components were identified from G. burmanicum, including 12 flavonoids and 35 triterpenoid saponins, among which 6 were new compounds. Saponins in G. burmanicum generally exhibited malonylation and acetylation, appearing after the corresponding prototypical saponins on a reversed phase chromatography. The base peak ion (BPI) chromatograms showed that the saponins of G. burmanicum were highly consistent with those of G. longipes, with comparable contents of the main components gypenoside XLIX and gypenoside A and their malonylated derivatives. In summary, this study comprehensively clarified the chemical composition and characteristics of G. burmanicum, which provided an experimental basis for the development and utilization of G. burmanicum.