Phytopathogenic fungi cause major agricultural losses worldwide. Their control relies largely on synthetic fungicides, which raise concerns related to environmental impact, resistance development, and human health. Botanical extracts represent a promising, sustainable alternative, and members of the Brassicaceae family are recognized as rich sources of antifungal metabolites. In this study, the antifungal activity of ethanol extracts from Brassica napus and Capsella bursa-pastoris was evaluated against Botrytis cinerea, Colletotrichum acutatum, and Fusarium oxysporum, which are major phytopathogens widely recognized for causing significant diseases in diverse commercial crops worldwide. Antifungal effects on mycelial radial growth and conidial production were assessed in vitro using the amended culture medium assay. Extracts were chemically characterized by LC-DAD-ESI-MS, and a single-Y orthogonal partial least squares (OPLS) analysis was applied to integrate chemical and bioactivity data to identify metabolites associated with antifungal activity. Test botanical extracts showed organ- and pathogen-dependent antifungal activity. B. napus was more active, as seeds reduced B. cinerea growth, and roots strongly suppressed conidiation and inhibited F. oxysporum. In contrast, C. bursa-pastoris was less effective, with only the flower and fruit extracts causing modest reductions in F. oxysporum, while the other extracts were largely inactive. Fourteen metabolites were tentatively identified based on UV-Vis and mass spectral data. Among them, one flavanol and two indole-containing compounds were statistically correlated with antifungal activity, were subsequently isolated, and were structurally confirmed by NMR spectroscopy. These compounds (1–3) exhibited reasonable antifungal activity (IC50 < 40 µM). The integrative covariate-based metabolic profiling approach proved operative for identifying bioactive constituents in the test botanical extracts, supporting the potential of Brassicaceae-derived extracts and their metabolites as natural antifungal agents.
Fierro-Cruz et al. (Mon,) studied this question.