Comprehensive metabolomics and phytochemical analyses identified important metabolites involved in the antioxidant activity of four Swiss chard cultivars (Beta vulgaris L. var. cicla) with different leaf colours

Beta vulgaris L. var. cicla is a leaf vegetable and has been used in many cuisines worldwide for a long time. The long history of Swiss chard cultivation has resulted in the development of many cultivars through domestication and hybridisation. The diversification of Swiss chard cultivars has resulted in differences in metabolite profiles. However, comparative studies analysing metabolites among cultivars are still lacking. In this study, 63 metabolites were identified in four Swiss chard cultivars with different leaf petiole colours using HPLC, GC–qMS, and GC–TOFMS. In addition, the antioxidant activity, TPC, and TFC were determined in extracts from the four Swiss chard cultivars. Comprehensive metabolic profiling analysis was performed using metabolites identified in Swiss chard. In addition to flavonoids, the metabolomic data and antioxidant assay identified non-flavonoid metabolites, such as policosanol, carotenoids, and glutamic acid derivatives, as strong antioxidant candidates that were not previously recognized as antioxidants in Swiss chard. • Metabolic profiling and antioxidant activities in different Swiss chard leaves. • Totally 63 known metabolites were identified in different leaves. • The heat map showed that most metabolites were high in red and white cultivars. • KEGG enrichment analysis showed that various nutraceutical pathways were impacted. • Several non-flavonoid metabolites might responsible for the antioxidant activity.