Comprehensive Organ-Specific Phenolic Characterization of Endemic Hedysarum candidissimum by Liquid Chromatography–Tandem Mass Spectrometry: Antioxidant, Enzyme-Inhibitory, and Antiproliferative Activities Supported by Chemometric Analysis

Hedysarum candidissimum (HC), a species endemic to Türkiye, represents a potential source of bioactive phytochemicals with pharmacological applications. This study provides the first comprehensive investigation of the species, integrating organ-specific phytochemical profiling with biological activity evaluations. Methanolic extracts from leaf, stem, and root were analyzed for their phytochemical composition and biological activities. Liquid Chromatography–Tandem Mass Spectrometry analysis quantified 53 phenolic compounds and revealed organ-dependent differences in metabolite distribution. Quinic acid was the major phenolic acid, with the highest content in the stem (91.81 mg/g extract), while flavonoid glycosides such as isoquercitrin (90.72 mg/g extract) and astragalin (43.61 mg/g extract) were higher in leaves. Antioxidant activity was determined by DPPH, FRAP, TPC, and TFC assays. The leaf extract showed the strongest activity, with the lowest DPPH IC50 (5.43 ± 0.18 µg/mL), highest reducing power (192.47 ± 0.91 mg TE/g extract), and highest phenolic and flavonoid contents (220.84 ± 1.07 mg GAE/g extract and 107.26 ± 0.77 mg QE/g extract). Enzyme inhibition assays demonstrated strong activity against acetylcholinesterase, butyrylcholinesterase, and α-glucosidase (2.44 ± 0.11, 3.35 ± 0.37, and 3.40 ± 0.20 µg/mL). Antiproliferative activity showed moderate growth inhibition in lung (A549, Calu1, H1650) and breast (MCF-7, MDA-MB-231) cancer cell lines (GI50: 2.40–19.15 µg/mL), with higher sensitivity in breast cells. The stem extract exhibited the highest tumor selectivity index (1.83), while LDH assays indicated low toxicity. Multivariate analyses confirmed organ-specific metabolite patterns and relationships between phenolic composition and biological activities. These findings indicate that the species, particularly the leaf extract, represents a source of phenolic metabolites for further phytochemical and biological investigation. © 2026 Royal Society of New Zealand Te Apārangi.