Chemical fingerprint analysis and metabolic profiling of 50% ethanol fraction of Lomatogonium rotatum by ultra-performance liquid chromatography/quadrupole-time of flight mass spectrometry.

Lomatogonium rotatum (L.) Fries ex Nym (L. rotatum), a member of Gentianaceae, is an important mongolian medicine in China used to treat febrile diseases in liver and gallbladder. The aim of present study was to investigate the chemical constituents and metabolites of the 50% ethanol fraction of L. rotatum (50EtLR). Firstly, the extract of L. rotatum was partitioned by macroporous resin to obtain the target fraction (50EtLR), then several compounds were isolated from 50EtLR to obtained the standards for further analysis of chemical constituents of 50EtLR. Secondly, the chemical constituents of 50EtLR were characterized using the ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Finally, prototype constituents and related metabolites were analyzed after orally administerng 50EtLR to rats. As a result, a new compound, 6-O-[β-d-xylopyranosyl-(1 → 6)-O-β-d-glucopyranosyl]-1,4,8-trimethoxyxanthone (6) along with seven known compounds (1-5, 7 and 8) were isolated from the 50EtLR, 92 components were either unambiguously or tentatively identified. Additionally, 34 prototype constituents and 112 metabolites in rat plasma along with 32 prototype constituents and 53 metabolites in rat liver were tentatively identified. Therefore, xanthones and flavonoids were the main chemical constituents of 50EtLR and sulfation and glucuronidation are the main enzyme-induced metabolic pathways involved post-administration.