Study on Dehydroabietic Acid-Based Schiff Derivatives from Natural Rosin as Potential Antifungal Agents

To develop an environmentally friendly rosin-based fungicide for controlling fusarium crown rot, a series of dehydroabietyl-Schiff-based derivatives were designed and synthesized. All compounds were validated by FT-IR, 1H NMR, 13C NMR, and LC-MS spectroscopies. In vitro activity assays showed that compound 4o (Co. 4o) significantly inhibited the growth of Fusarium pseudograminearum (half-maximal effective concentration, EC50 = 5.45 μg/mL), and in vivo activity measurement results suggested that Co. 4o exhibited a certain protective effect on wheat plants. Mycelial morphological observations revealed that Co. 4o produced severe damage to the mycelial surface morphology and ultrastructure. Reactive oxygen species (ROS) staining indicated that treatment with Co. 4o led to the accumulation of substantial ROS in the mycelium. Physiological assays indicated Co. 4o significantly inhibited superoxide dismutase, peroxidase, catalase, and polyphenol oxidase protein activity. Molecular docking studies suggested that the Schiff-based group in Co. 4o could form hydrogen bonds with various amino acids. In summary, these results demonstrate that Co. 4o holds potential as an antifungal candidate for controlling fusarium crown rot.