An integrated strategy for comprehensive characterization of chemical components in Qingqiao Kangdu granules by UHPLC-Q-Exactive-MS coupled with feature-based molecular networking

Qingqiao Kangdu granule (QQKDG), a traditional Chinese medicine (TCM), has been used clinically to treat various viral diseases, including flu, mumps, and viral hepatitis, owing to its abundant bioactivities. Nevertheless, the chemical components of QQKDG have not been sufficiently elucidated; consequently, the development of standards for quality evaluation and complete understanding of the pharmacological mechanisms of action are hindered. Therefore, a systematic approach must be developed to efficiently discover novel compounds and advance pharmacological research. In this regard, this study proposed an integrated strategy for the comprehensive characterization of the chemical components in QQKDG by UHPLC-Q-Exactive-MS coupled with featurebased molecular networking (FBMN) to improve annotation accuracy and achieve visualization. First, the chromatographic and mass spectrum conditions were optimized to obtain good separation and abundant signal response. Subsequently, an in-house library was established by searching for relevant literature to improve annotation confidence. Finally, the raw data acquired under optimized conditions were uploaded to the FBMN to achieve component visualization by connecting precursor ions of the same color, in which compounds have similar structural features. Thus, a total of 231 compounds, including 89 flavonoids, 36 phenolic acids, 26 phenylethanoid glycosides, 23 coumarins, 17 chlorogenic acid derivatives, 14 terpenoids, 10 alkaloids, 10 lignans and 6 other compounds, were characterized, and numerous novel compounds with new structures were explored. Thus, this study provides a strategy for comprehensive characterization, which can also be applied to other TCMs.