Organ-Specific Phenolic Profiling and Integrated Antioxidant Evaluation of Cicer isauricum by LC–ESI–MS/MS and Multi-Assay Approach

This study presents an integrated evaluation of the organ-specific phenolic composition and antioxidant activity of Cicer isauricum. Extracts obtained from leaves, stems, and roots were analyzed using liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) and multiple in vitro antioxidant assays. LC–MS/MS analysis revealed a distinct organ-dependent distribution of phenolic compounds. Stem extracts were characterized by high levels of hyperoside (2227.97 µg/g extract), luteolin (298.22 µg/g), and eriodictyol (434.03 µg/g), while leaves were rich in hyperoside (1162.42 µg/g), hesperidin (459.40 µg/g) and kaempferol (182.88 µg/g). Root extracts were dominated by flavan-3-ols, particularly (+)-catechin (355.93 µg/g) and (–)-epicatechin (59.58 µg/g), indicating a differentiated metabolic profile. Antioxidant assays, including cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, demonstrated that root extracts exhibited the strongest activity, with the lowest IC50 values (DPPH: 4.15 mg/mL; ABTS: 1.41 mg/mL) and highest reducing power (FRAP EC50: 0.41 mg/mL; CUPRAC EC50: 1.78 mg/mL). Correlation analysis confirmed strong associations between total phenolic content and antioxidant capacity, while compound-level evaluation highlighted flavan-3-ols as major contributors. These findings identify roots of C. isauricum as a promising source of natural antioxidants.