Systematic identification metabolites of Hemerocallis citrina Borani by high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry combined with a screening method

Hemerocallis citrina Borani is an important crop and its flower buds are widely consumed in East Asian areas as a vegetable, as well as in traditional Chinese medicine, due to its health-promoting properties. Metabolites present in plant-derived foods or medicines are in part responsible for their desirable flavor profiles and health benefits. Nevertheless, detailed information about these compounds in H. citrina is scarce. Therefore, this study aimed to investigate the metabolites by high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). In this study, a total of 144 compounds, including 14 amides, 25 polyphenols, 44 flavonols, 35 anthraquinones, 15 naphthols, and 11 other components, were detected by the established screening method and were identified by their precise m/z values, characteristic tandem mass spectrometry (MS/MS) data and fragmentation pathways of references, 111 of which were reported in this plant for the first time. The distribution of identified ingredients in different parts of H. citrina was determined. Interestingly, colchicine, which had been reported as a toxic compound in the fresh flower buds in previous studies and various news reports, was not found. This work marks the first comprehensive study of metabolites from commercial flower buds and different parts of H. citrina.