To discover novel preservatives for
treating wood-decaying fungi,
48 novel eugenol quaternary ammonium salt derivatives were designed
and synthesized. Among them, compounds <b>3j</b>, <b>3k</b>, <b>4j</b>, <b>4k</b>, <b>5j</b>, <b>5k</b>, and <b>6j</b> showed remarkable antifungal activity against Gloeophyllum trabeum (G. trabeum), affording EC<sub>50</sub> values ranging from 2.11–7.50
μg/mL. Notably, <b>3j</b> demonstrated the most potent
activity against G. trabeum (EC<sub>50</sub> = 0.14 μg/mL), surpassing the positive control dodecyldimethylbenzylammonium
chloride (DDBAC, EC<sub>50</sub> = 3.33 μg/mL). Additionally, <b>3j</b> significantly reduced wood mass loss and decay caused by G. trabeum. Mechanistic studies revealed that <b>3j</b> disrupted the fungal ultrastructure, increased membrane
permeability, and induced cellular leakage. Furthermore, <b>3j</b> disrupted the antioxidant system and energy metabolism, resulting
in the accumulation of reactive oxygen species. The multiomics data
revealed the molecular mechanisms by which <b>3j</b> regulated G. trabeum, including key genes, proteins, metabolites,
and pathways. This study elucidates key mechanistic insights into
developing a natural-product-derived wood preservative.