Thirty chromone derivatives, both synthetic and natural, were assayed for feeding deterrent activity against Spodoptera litura larvae to establish structure-activity relationships. Among the compounds tested, furochromones with alkoxy substituents at C-4 or C-9 exhibited maximum feeding deterrent activity. Loss of activity was noticed with the degradation or saturation of either of the heterocyclic rings. Substitution of C-7 methyl of the gamma-pyrone ring and dealkylation of C-4 or C-9 methoxyl also caused considerable reduction in feeding deterrent activity.
D. Lakshmicha Luthria, Ramakrishnan, V., and Banerji, A., “Insect antifeedant activity of furochromones: Structure-activity relationships”, Journal of natural products, vol. 56, pp. 671–675, 1993.