Discovery of N-phenyl-isoindole-1,3-dione derivatives as potent insect chitinase OfChi-h inhibitors through virtual screening

• A novel class of N-phenyl-isoindole-1,3-dione ( PI ) derivatives was identified as potent inhibitors of O f Chi-h via virtual screening. Compound PI-17 demonstrated strong inhibitory activity against O f Chi-h ( K i =2.3 μmol L -1 ) and superior insecticidal efficacy against Ostrinia furnacalis . • PI -series induced morphological aberrations in the cuticles of O . furnacalis larvae. The mechanism of this efficient insecticidal action was elucidated at atomic and electronic levels through Electrostatic potential (ESP) and density functional theory (DFT) analyses. • PI -series compounds demonstrated significant potential as eco-friendly insect growth regulators, with comprehensive safety assessments confirming minimal effects on natural enemies and non-target organisms. Ostrinia furnacalis represents a destructive lepidopteran pest causing up to 30% yield losses in maize crops globally. Its larvae penetrate plant tissues, disrupt nutrient transport, and transmit viral and microbial pathogens, exacerbating food security concerns. Current management approaches for O . furnacalis primarily rely on synthetic pesticides. Targeting chitin metabolism presents a promising strategy for green insecticide development. Specifically, O f Chi-h, an essential chitinase for O . furnacalis molting and survival, has emerged as a viable target. This study identified a N-phenyl-isoindole-1,3-dione ( PI ) scaffold as a novel class of O f Chi-h inhibitor through virtual screening strategy. Notably, compound PI-17 demonstrated potent inhibitory activity against O f Chi-h with a K i value of 2.3 μmol L -1 . PI-17 exhibited significant insecticidal activity against lepidopteran pests O . furnacalis , comparable to the control drug hexaflumuron. scanning electron microscopy (SEM) analysis revealed morphological alterations in the cuticles of O . furnacalis larvae treated with PI -series compounds. ESP and DFT calculations explored the variations in biological activities of the PI -series compounds at atomic and electronic levels. Additionally, comprehensive safety evaluations assessed the impact on the natural enemy Trichogramma ostriniae and nontarget organisms. These findings introduce a novel class of lead compounds, N-phenyl-isoindole-1,3-dione derivatives, showing significant potential for developing eco-friendly insect growth regulators to control O . furnacalis .