Species and Accession Diversity of Secondary Metabolites and Antioxidant Activity in Legume Sprouts

Legume sprouts contain diverse bioactive phytochemicals, yet species- and accession-level comparisons of antioxidant properties and secondary metabolites remain limited. Antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and 19 secondary metabolites were evaluated in sprouts of soybean ( Glycine max (L.) Merr.), mungbean ( Vigna radiata (L.) R. Wilczek), cowpea ( Vigna unguiculata (L.) Walp.), and peanut ( Arachis hypogaea L.), using ten accessions per species under standardized conditions. Mungbean and cowpea sprouts showed significantly higher antioxidant activity, TPC, and TFC than soybean and peanut; across accessions, ABTS and DPPH activities ranged from 13.67 to 49.33% and 7.91 to 55.16%, and TPC and TFC from 3.91 to 13.81 mg GAE/g and 0.05 to 1.04 mg QE/g, respectively. Metabolite profiling revealed species-specific patterns, including isoflavones in soybean, rutin in mungbean, coumestrol in cowpea and resveratrol in peanut. Both antioxidant and phytochemical profiles varied with species and accession, so both can be selected to obtain sprouts with targeted properties.