Discovery of 2-Cinnamoylbenzimidazoles as Novel Insect and Fungal Trehalose-6-Phosphate Phosphatase Inhibitors

Trehalose-6-phosphate phosphatase (TPP), a key enzyme in trehalose biosynthesis, represents a promising target for pest and fungal control due to the absence of TPP in higher animals. However, few TPP inhibitors have been reported, and broad-spectrum agents targeting both insects and fungi remain scarce. In this study, 2-cinnamoylbenzimidazole was identified as a dual-targeting inhibitor scaffold against insect and fungal TPPs. Structure-guided optimization by pocket size yielded 5-1 (Ki = 1.3 μM) for insect TPP and 5-3 (Ki = 17.3 μM) for fungal TPP. Molecular docking revealed that 2-cinnamoylbenzimidazole forms hydrogen bonds with conserved active-site residues, while its aryl ring occupies a hydrophobic subsite. Biological assays demonstrated that ingestion of 1 mM 5-1 caused 100% mortality in Plutella xylostella larvae and reduced locomotion in Locusta migratoria, concomitant with marked reductions in hemolymph trehalose and glucose. This work provides a novel TPP inhibitor scaffold, demonstrates a structure-guided optimization strategy, and establishes a foundation for developing multifunctional pesticides.