Exploring the growth inhibition potential of monoketone curcuminoids against Spodoptera frugiperda

Abstract

Spodoptera frugiperda, known as the fall armyworm (FAW), is a polyphagous pest that causes huge economic losses in different agricultural regions of the world. Its control is challenging due to its widespread resistance to conventional insecticides and Bt events. This study aimed to assess the lethal toxicity and growth-inhibitory effects of eight acetone-derived monoketone curcuminoids (MKCs) on S. frugiperda larvae. MKCs were synthesized by Claisen-Schmidt condensation between acetone and aromatic aldehydes in a basic medium and tested against FAW larvae at a concentration of 250 mg kg-1 (dietary exposure) over 7 days. None of the tested compounds showed a significant lethal toxicity to FAW. However, halogenated MKCs derivatives 4 ((1E,4E)-1,5-bis(4-fluorophenyl)penta-1,4-dien-3-one) and 5 ((1E,4E)-1,5-bis(4-chlorophenyl)penta-1,4-dien-3-one) exhibited sublethal effects, reducing larval weight by 59% and 55%, respectively, compared to the negative control. These results indicated that the halogenation of MKCs may be a promising strategy to be exploited in the search for novel bioactive compounds to manage FAW in agricultural food production systems. Keywords: Claisen-Schmidt condensation; fall armyworm; halogenated compounds; monoketone curcuminoids