LC–MS/MS-Based Comparative Phytochemical Profiling and Multivariate (PCA) Analysis of Seed Extracts from Trigonella foenum-graecum, Linum usitatissimum, and Panicum miliaceum with Emphasis on Antioxidant and Antibacterial Activities

Abstract

This study provides a comprehensive evaluation of the phytochemical composition, antioxidant capacity, antibacterial activity, and mineral content of Trigonella foenum-graecum, Linum usitatissimum, and Panicum miliaceum extracts obtained using aqueous, ethanolic, and methanolic solvents. An integrated analytical strategy combining LC–MS/MS-based metabolite profiling, mineral analysis, and multivariate statistical tools (PCA) was applied to investigate the relationships between chemical composition and biological activities. The ethanolic extract of P. miliaceum showed the highest total phenolic content (TPC: 157.438 ± 0.521 µg GAE/mg extract), whereas L. usitatissimum exhibited the strongest antioxidant activity (IC50 ≈ 65 µg/mL). Trigonella foenum-graecum displayed the most significant antibacterial activity, with a minimum inhibitory concentration (MIC) of 62.5 mg/mL against Staphylococcus aureus. LC–MS/MS analysis allowed the identification and structural characterization of more than twenty bioactive compounds through multiple reaction monitoring (MRM), including flavonoids, phenolic acids, and anthocyanins. Principal Component Analysis indicated that sample discrimination was mainly driven by solvent polarity rather than plant species, underlining the critical influence of extraction conditions on phytochemical profiles and associated bioactivities. These findings highlight the relevance of combining analytical and statistical approaches to better understand the interplay between plant origin, extraction conditions, and biological properties, and support the potential of these species as promising sources of nutraceutical and pharmaceutical compounds.