Nutritional profile, chemical composition, and bioactivities of an underexplored edible Elatostema stewardii using UPLC-QE-orbitrap-HRMS metabolomics integrated with chemometrics.

Elatostema stewardii is traditionally consumed as both a vegetable and a flavoring agent; however, its phytochemical composition and functional properties remain poorly understood. This study investigated the nutritional profile, metabolite composition, and biological activities of different plant parts using an integrated approach combining untargeted metabolomics based on ultra-performance liquid chromatography-Q Exactive Orbitrap high-resolution mass spectrometry (UPLC-QE-Orbitrap-HRMS), chemometric analysis, and multiple bioassays. On a dry-weight basis, leaves and stems were rich in protein (19.0-21.1 g/100 g), dietary fiber (27.66-28.73 g/100 g), flavonoids (110-630 mg rutin equivalents/100 g), and minerals, particularly calcium in leaves (6580 mg/100 g) and potassium in stems (5460 mg/100 g). Metabolomic profiling annotated 707 metabolites, including fatty acids, flavonoids, and terpenoids. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) clearly discriminated plant parts and identified 58 differential metabolites as potential organ-specific markers. Bioactivity evaluation showed distinct plant-part-dependent effects. The primary root exhibited potent acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition (IC50 = 0.10 and 0.41 μg/mL), comparable to tacrine, along with strong antioxidant capacity comparable to l-ascorbic acid, as evidenced by DPPH (IC50 = 8.02 μg/mL), ABTS (IC50 = 10.30 μg/mL), and FRAP (0.24 μmol Fe2+/mL) assays. It also showed higher anti-inflammatory effects, while both primary roots and leaves displayed stronger cytotoxic potential against five human cancer cells. S-plot analysis further revealed 99 biomarkers including known bioactive compounds, such as 18α-glycyrrhetinic acid, catechin and vicenin 2. Collectively, these findings provide scientific evidence supporting the traditional dietary use of E. stewardii and highlight its potential as a promising source of functional food or nutraceutical ingredients.