Comprehensive metabolome profiling highlights the biochemical basis of antioxidant capacity in 7 edible and inedible Allium species

Abstract

The metabolome of the aerial parts of 7 Allium species was cataloged via a multiplex metabolomics approach. This analysis encompassed edible (red/white onion, Egyptian/French leek) and inedible (red/white garlic, chives) parts. UPLC-HRMS/MS enabled the annotation of 75 peaks belonging to organosulfur compounds, flavonoids, spirostane steroids, porphyrins, etc. 1D- and 2D-NMR fingerprinting identified 34 metabolites belonging to fatty acids, sugars, organic acids, amino acids, etc. Additionally, the total phenolic content and antioxidant effects were evaluated, revealing chives had the strongest antioxidant capacity. Correlation between UPLC-HRMS/MS metabolite profiles and antioxidant activity identified flavonoids and phospholipids as the major contributors, especially kaempferol derivatives, and to a lesser extent quercetin conjugates. These results highlight the biochemical basis of antioxidant capacity in Allium and underscore the value of integrative metabolomics for linking phytochemical diversity with functional activity, offering insights into the genus's nutritional potential.