Antifungal Activity of Brassica rapa-Derived Extracts Against F. oxysporum

Fusarium oxysporum is a cosmopolitan fungus with agronomic importance due to the economic losses associated with vascular wilt, caused to more than 100 species of gymnosperms and angiosperms. F. oxysporum resistance to commercially available fungicides and the high incidence of synthetic fungicide applications requires the introduction of new alternatives in the control strategies. The family Brassicaseae has been reported as a source of antimicrobial agents. In the present work, Brassica rapa (a wild plant widely distributed in Cundimarca, Colombia) was used. The plant was separated in seeds, stems-leaves, and roots, and then macerated with ethanol. F. oxysporum was seeded on PDA medium separately supplemented with each extract and radial growth was assessed after 6 days. All Brassica rapa extracts exhibited dose dependent antifungal activity at different levels. Root-derived extract showed inhibition percentages above 45% between 10 – 0.1 µg/µL. Stem-leaf and seed-derived extracts also showed reasonable inhibition (> 30% and > 35%, respectively) in the same concentration range. In addition, in order to chemically characterize, compare and highlight main components on each extract, a LC-DAD-based profiling were performed. All data were correlated by principal component analysis (PCA). A composition-activity relationship was observed.