Synthesis and antifungal activity evaluation of novel dehydroabietic acid‐based Schiff base derivatives for sustainable agricultural protection

BACKGROUND Plant diseases cause significant economic losses in global agriculture each year, and the long‐term use of commercial fungicides has led to serious environmental pollution and pesticide resistance. Therefore, there is an urgent need to develop effective and eco‐friendly plant‐based antifungal compounds. RESULTS A series of rosin‐based Schiff base derivatives were synthesized, and all compounds were charactered using FT‐IR, 1 H NMR, 13 C NMR and LC–MS. In vitro antifungal activity evaluation revealed that compound 4o (4o) exhibited excellent antifungal activity against Fusarium graminearum , with an EC 50 value of 1.088 μg/mL. The preliminary structure–activity relationship analysis suggested that introducing electron‐donating groups onto the benzene ring enhanced antifungal activity. Additionally, mycelial morphological observation indicated that after treatment with 4o, the mycelium exhibited noticeable shrinkage on the outside, and a significant accumulation of reactive oxygen species inside. Finally, mycelial physiological index measurement showed that after treatment with 4o, mycelial cell membrane permeability increased to 65.56%, malondialdehyde content rose by 60.17%, and catalase enzyme activity significantly decreased by 94.67%. The results of molecular dynamics calculations indicate that there is a strong interaction between 4o and CAT proteins, with van der Waals forces playing a major role. CONCLUSION This study provides theoretical support for the development of a novel plant‐based antifungal compound for agricultural protection.