Isovitexin and schaftoside from rice plants have antifeedant activity on brown planthoppers.

Background: Many secondary metabolites of plants have antifeedant activity against herbivorous insects and can be used as antifeedants in green plant protection. However, it is not clear whether the secondary metabolites of rice plants can act on the brown planthopper (BPHs) Nilaparvata lugens and can be used for pest control. In this study, we screened two flavonoids from rice plants that increased under N. lugens damage. To clarify the effect of these two flavonoids on N. lugens and evaluate their practical application potential, the effects of the two flavonoids on the feeding behavior and physiological status of N. lugens were studied by artificial feed addition and root irrigation.

Results: Two flavonoids (isovitexin and schaftoside) were screened from rice plants induced by damage of N. lugens using metabolomics analysis. Through artificial feed addition combined with a feeding selection test and root irrigation combined with an electrical penetration graph (EPG) test, it was confirmed that isovitexin and schaftoside had antifeedant activity against N. lugens. We also showed that isovitexin and schaftoside significantly reduced the survival rate and body weight of N. lugens. Moreover, enzyme activity bioassay and molecular docking test showed that isovitexin and schaftoside interacted with the detoxification enzymes (including carboxylesterase (CarE), acetylcholinesterase (AChE), and glutathione S-transferase (GST)) and led to an increase in the activity of these detoxification enzymes of N. lugens.

Conclusion: This study verified that isovitexin and schaftoside have antifeedant activity and can be used as antifeedants for green plant protection against rice planthoppers. © 2025 Society of Chemical Industry.