Novel Butenolide Derivatives as Dual-Chitinase Inhibitors to Arrest the Growth and Development of the Asian Corn Borer

OfChtI and OfChi-h are considered potential targets for the control of Asian corn borer (Ostrinia furnacalis). In this work, the previously reported OfChtI inhibitor 5f was found to show certain inhibitory activity against OfChi-h (K-i = 5.81 mu M). Two series of novel butenolide derivatives based on lead compound 5f were designed with the conjugate skeleton, contributing to the pi-binding interaction to chitinase, and then synthesized. Compounds 4a-l and 7a-p displayed excellent inhibitory activities against OfChtI and OfChi-h, respectively, at a concentration of 10 mu M. Compound 4h was found to be a good dual-Chitinase inhibitor, with K-i values of 1.82 and 2.00 mu M against OfChtI and OfChi-h, respectively. The inhibitory mechanism studies by molecular docking suggested that pi-pi stacking interactions were crucial to the inhibitory activity of novel butenolide derivatives against two different chitinases. A preliminary bioassay indicated that 4h exhibited certain growth inhibition effects against O. furnacalis. Butenolide-like analogues should be further studied as promising novel dual-chitinase inhibitor candidates for the control of O. furnacalis.