Rapid chemical characterization of finger millet using UHPLC-Q-Exactive orbitrap MS coupled with based via Feature-Based molecular networking and PRM

Abstract Finger millet (Eleusine coracana L., EC) is a nutritionally dense and medicinally valuable cereal crop with a long history of use in traditional health practices. Contemporary pharmacological studies have demonstrated that extracts from EC and its individual chemical constituents exhibit a wide range of health benefits and therapeutic properties. For instance, they possess antioxidant activity, can reduce blood glucose levels, and enhance gastrointestinal health. However, the full spectrum of their chemical constituents remains to be fully elucidated. In this study, we established a state-of-the-art analytical workflow integrating Ultra-High-Performance Liquid Chromatography coupled with Quadrupole-Orbitrap Mass Spectrometry (UHPLC-Q-Exactive Orbitrap MS) with Feature-Based Molecular Networking (FBMN) and Parallel Reaction Monitoring (PRM) for comprehensive chemical profiling of EC. A total of 126 compounds were unambiguously identified, including 64 flavonoids, 24 phenylpropanoids, 21 organic acids, and 22 other metabolites. Notably, 44 of these represent novel reports in EC, significantly expanding its known chemical repertoire. Further verification via Western Blot (WB) showed that the ethanol extract of EC (1 ~ 100 µg/mL) could concentration-dependently inhibit the overexpression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proteins in lipopolysaccharide (LPS)-induced RAW264.7 macrophages, which initially confirms its in vitro anti-inflammatory activity. The analytical method established in this study enables rapid and efficient identification of the major chemical constituents of EC, laying a foundation for its quality control, exploration of bioactive components, and mechanism research.