Evaluation of antifungal and antimycotoxigenic activity of selected natural antioxidants against Fusarium culmorum : in vitro and in planta assays

Abstract

Background: Fusarium culmorum causes Fusarium head blight (FHB) in cereals, leading to significant yield losses and contamination with type B trichothecene mycotoxins such as deoxynivalenol (DON) and its acetylated derivatives 3-ADON and 15-ADON. Due to the limitations of chemical fungicides, there is increasing interest in sustainable alternatives. Naturally occurring antioxidants have shown potential in modulating fungal growth and mycotoxin production. Results: This study evaluated the effects of 11 natural antioxidant compounds on Fusarium culmorum growth and trichothecene production, both in vitro and in planta. In vitro: octyl gallate (7), honokiol (9), and magnolol (10) completely inhibited fungal growth and trichothecene production at 0.5 mmol L−1. In planta: octyl gallate (7), reduced the disease index to 0.63% and total mycotoxin levels by 90% while honokiol (9), and ascorbic acid (1) exhibited notable inhibition in both disease severity and mycotoxin accumulation. The equimolar combination of ascorbic acid and tocopherol demonstrated synergistic inhibition of DON and 3-ADON in vitro, though its efficacy in planta was moderate. No correlation was found in vitro between the antioxidant or lipophilic properties and antifungal efficacy, whereas in planta experiments revealed a positive correlation between antioxidant activity and trichothecene suppression. Statistical analysis was performed using Shapiro–Wilks, Levene and analysis of variance tests (P ≤ 0.05). Conclusions: Natural antioxidants, particularly octyl gallate and honokiol, represent promising candidates for controlling F. culmorum and reducing trichothecene contamination in cereals. Their application could contribute to safer food by reducing trichothecene levels through environmentally friendly strategies. Further research is needed to optimize formulations and assess field-level efficacy.