Insecticidal activity of essential oils from American native plants against Aedes aegypti (Diptera: Culicidae): an introduction to their possible mechanism of action

Searching for new bioactive molecules to design insecticides is a complex process since pesticides should be highly selective, active against the vector, and bio-safe for humans. Aiming to find natural compounds for mosquito control, we evaluated the insecticidal activity of essential oils (EOs) from 20 American native plants against Aedes aegypti larvae using bioassay, biochemical, and in silico analyses. The highest larvicide activity was exhibited by EOs from Steiractinia aspera (LC50 = 42.4 mu g/mL), Turnera diffusa (LC50 = 70.9 mu g/mL), Piper aduncum (LC50 = 55.8 mu g/mL), Lippia origanoides (chemotype thymol/carvacrol) (LC50 = 61.9 mu g/mL), L. origanoides (chemotype carvacrol/thymol) (LC50 = 59.8 mu g/mL), Hyptis dilatata (LC50 = 61.1 mu g/mL), Elaphandra quinquenervis (LC50 = 61.1 mu g/mL), and Calycolpus moritzianus (LC50 = 73.29 mu g/mL) after 24 h. This biological activity may be related to the disruption of the electron transport chain through the mitochondrial protein complexes. We hypothesized that the observed EOs' effect is due to their major components, where computational approaches such as homology modeling and molecular docking may suggest the possible binding pose of secondary metabolites that inhibit the mitochondrial enzymes and acetylcholinesterase activity (AChE). Our results provided insights into the possible mechanism of action of EOs and their major compounds for new insecticide designs targeting the mitochondria and AChE activity in A. aegypti for effective and safe insecticide.

Automated summary

Searching for new bioactive molecules for insecticides is complex, and highly selective, active against the vector, and bio-safe for humans. Essential oils from 20 American native plants were evaluated for their insecticidal activity against Aedes aegypti, with the most effective being Steiractinia aspera, Turnera diffusa, Piper aduncum, Lippia origanoides, Hyptis dilatata, Elaphandra quinquenervis, and Calycolpus moritzianus. The activity may be due to disruption of the electron transport chain through mitochondrial protein complexes. Computational approaches were used to analyze the binding of secondary metabolites to mitochondrial enzymes and acetylcholinesterase activity.