Integrated metabolomics and antioxidant activity assessment of Sphagneticola trilobata (L.) Pruski

Sphagneticola trilobata (L.) Pruski (Asteraceae), formerly known as Wedelia trilobata, is a widely distributed ornamental plant utilized in traditional medicine for various ailments. This study aims to provide the first comprehensive comparative analysis of the metabolomic profiles of Sphagneticola trilobata flowerheads and leaves to elucidate the chemical basis for their differential antioxidant capacities. Ultra-high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry was employed in both positive and negative ionization modes. The resulting datasets were subjected to multivariate chemometric analyses, including Principal Component Analysis and Orthogonal Partial Least Squares Analysis. Antioxidant potential was assessed using in vitro DPPH, FRAP, and ABTS assays. A total of 86 metabolites were tentatively annotated, spanning classes of terpenoids, flavonoids, phenolic acids, lipids, and amino acids. Notably, 18 of these compounds were observed in this plant for the first time. Chemometric analysis revealed distinct metabolic variances: flowerheads were enriched with flavonoids and phenolic acids, whereas leaves were characterized by a predominance of sesquiterpenoids and diterpenoids. Biological assays demonstrated that flowerheads possess significantly higher antioxidant activity compared to leaves. Moreover, correlation analysis identified key biomarkers responsible for this activity, including 3',4',7-trihydroxy-flavanone hexoside, luteolin, myricetin hexoside, and 4,5-dicaffeoyl-quinic acid. The study establishes that the superior antioxidant potential of Sphagneticola trilobata flowerheads is driven by their high flavonoid and phenolic acid content, distinguishing them from the terpenoid-rich leaves. These findings validate the utility of metabolomics in identifying bioactive markers and suggest the flowerheads as a promising source of natural antioxidants for pharmaceutical or cosmeceutical applications.