Development of larvicide nanoemulsion from the essential oil of Aeollanthus suaveolens Mart. ex Spreng against Aedes aegypti, and its toxicity in non-target organism

Abstract

The widespread use of synthetic insecticides to control diseases such as those transmitted by the vector Aedes aegypti (Linnaeus, 1762) has caused widespread resistance to mosquitoes and adverse effects on non-target organisms, such as humans and animals. In this sense, nanotechnology emerges as a strategy for developing new promising insecticidal agents against this vector. Therefore, this research developed a nanoemulsion containing A. suaveolens essential oil, as well as to evaluate the larvicidal activity of the nanoemulsion against A. aegypti and toxicity in non-target mammals. The essential oil was identified by gas chromatography coupled to a mass spectrometer, and the nanoemulsions were prepared using a low-energy method and characterized by photon correlation spectroscopy. The larvicidal activity was evaluated against A. aegypti larvae at the third stage of development, and acute oral toxicity was assessed on mice. The results showed that the main compounds found were Massoialactone (64.79%), Linalool (7.83%), and (E)-β-Farnesene (6.17%). The most stable nanoemulsion was produced in HLB 15 with a particle size of 126.73 ± 0.20 nm, polydispersity index of 0.125 ± 0.01, and zeta potential of −16.25 ± 1.48 mV after 21 days. The LC50 and LC90 values in A. aegypti larvae after 24 h were 54.23 µg.mL−1 and 96.96 µg.mL−1, respectively. After 48 h, the values were LC50 of 46.06 µg.mL−1 and LC90 of 75.31 µg.mL−1. Regarding the acute oral toxicological evaluation, the results showed that despite A. suaveolens essential oil nanoemulsion (NEOAS) having a lethal dose (LD50) greater than 2000 mg.kg−1, histological changes were observed in the kidneys and liver of treated animals. In this sense, this study allowed the development of an ecological and low-cost larvicidal nanoformulation for the control of A. aegypti.