Atividade larvicida da nanoemulsão do óleo essencial de Ocimum basilicum Linn (Lamiales: Lamiacea) em Aedes aegypti Linnaeus e Culex quinquefasciatus Say (Diptera: Culicidae)

Abstract

Mosquitoes of the species Aedes aegypti and Culex quinquefasciatus transmit a series of epidemic diseases, posing a threat to millions of humans and animals around the world. The present study aimed to evaluate the nanoemulsion larvicidal activity of the essential oil of the Ocimum basilicum leaves in A. aegypti and C. quinquefasciatus. The essential oil (OE) was obtained by hydrodistillation and the identifications of the bioactive constituents present in it were performed by gas chromatography and mass spectroscopy (GC-MS). Linalool was identified as the major compound, corresponding to 32.66% of the relative percentage of oil followed by Anethole with 32.48% that have a known insecticidal and repellent action. Several nanoemulsions were developed using a low energy input method, with the best results using Tween 20, suggesting that a hydrophilic-lipophilic balance of this oil is about 16.7 with a mean particle size of 294.9nm and polydispersity index of 0.070. In the bioassay of larvicidal activity, the nanoemulsion was tested at concentrations of 10, 20, 30, 40 and 50 mg / L in 4th instar larvae. After 24 and 48 hours of exposure, the following values were observed: LC50 = 42.15mg / L and 40.94mg / L and CL90 = 50.35mg / L and 48.87mg / L for A. aegypti; and LC50 = 39.64mg / L and 38.08mg / L and CL90 = 52.58mg / L and 54.26mg / L for C. quinquefasciatus, respectively. Thus, the nanoemulsion studied was highly efficient against A. aegypti and C. quinquefasciatus, becoming a potential alternative as a bioinsecticide