Characterization of Flavonoid Constituents in Stems of Lithocarpus litseifolius (Hance) Chun by UHPLC-Q-Exactive Orbitrap MS

Background: Lithocarpus litseifolius (Hance) Chun (L. litseifolius) has been used for treating diabetes, allergic and inflammatory diseases, and hyperlipidemia in folk medicine. Previous studies have shown that the main active ingredients of its leaves are flavonoids. However, to the best of our knowledge, the stem of L. litseifolius has not been investigated for its constituents yet. The stems of the decaying plants fall every year. It is considered as a waste due to limited knowledge of the benefits of these stems, which is a sheer waste of the plant resource. Therefore, it is necessary to investigate the chemical constituents of the stem, which will be beneficial for the treatment of many diseases and help utilize the stem in a better way instead of wasting the plant resource. Methods: In this study, the dry twigs of L. litseifolius were collected, powdered, and extracted. Then, the extracted sample was subjected to UHPLC-Q-Exactive Orbitrap MS in negative mode combined with Parallel reaction monitoring scanning to gain the high-resolution mass spectrum, which was processed by the Compound Discover version 3.0 using high resolution extracted ion chromatography to predict the constituent compounds. Results: A total of 35 flavonoids including flavone, flavonol, dihydroflavone, isoflavone, and dihydrochalcone were putatively identified based on their accurate mass measurement, chromatographic retention, MSn spectra, and bibliography data. Conclusion: In this study, a total of 35 flavonoids were identified in the stem of L. litseifolius, among which 5 flavonoids were the first to be reported from this plant, which will be very helpful for the development of medicines for the treatment of many diseases and utilization of the stem of L. litseifolius.