Characterization and identification of the chemical constituents in the root of Lindera reflexa Hemsl. using ultra-high performance liquid chromatography coupled with linear trap quadrupole orbitrap mass spectrometry

Abstract

The root of Lindera reflexa Hemsl. (LR) is a newly discovered herbal drug and has been used to treat gastritis and peptic ulcers. Nevertheless, the chemical profile of LR has not been established. In this study, ultra-high performance liquid chromatography coupled with linear trap quadrupole orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap-MS) was performed to investigate the fragmentation behaviors of multiple compounds from LR. The 12 standards were divided into five types according to their basic skeletons: stilbenes, flavonoids, alkaloids, pyranone I and pyranone II. The MSn spectra of the [M+H]+ or [M±NH4]+ ions for these compounds provided a wealth of structural information on the five different types of compounds. Stilbenes yielded ions with successive loss of 78Da (C6H6) and 28Da (CO). The subsequent loss of H2O, CO, RDA and C-ring fragmentation were the most possible fragmentation pathways for flavonoids. Fragmentation with successive loss of 17Da (NH3) or 31Da (CH5N), 32Da (CH4O) and 28Da (CO) in the MSn spectra were characteristics of alkaloids. The characteristic ions for Pyranone I were m/z 255.1013, m/z 243.1013 and m/z 237.0909, and the diagnostic ions for Pyranone II were m/z 227.0700, m/z 215.0700, m/z 185.0594 and m/z 131.0489. Using accurate mass measurements for each precursor ion and the subsequent fragmented ions, a total of 42 compounds were identified or tentatively characterized in LR, including 24 potentially new compounds.