Bioatividade do óleo essencial de Lippia grata Schauer frente a larvas de Aedes aegypti e Aedes albopictus

Abstract

Culicids are insects popularly known as mosquitos, muriçocas, mossorongos, sovelas, mosquitos-prego or carapanãs. The family Culicidae includes about 20 species of medical and veterinary importance. Among these are Aedes aegypti and Aedes albopictus, vectors of important arboviruses such as dengue, yellow fever, chikungunya, zika and other widespread diseases in Brazil. Brazil is one of the most biodiverse countries in the world, harboring about 24% of the known species of plants on the planet. Among the plants used in folk medicine that have been studied over the years is Lippia grata, a species that has been reported to have antiseptic, healing, antimicrobial and larvicidal properties. The aim of this study was to evaluate the bioactive potential of L. grata essential oil against larvae of A. aegypti and A. albopictus. Standardized WHO tests were performed with 3rd instar larvae, exposed to different concentrations of L. grata essential oil (20mg/ml, 12.5mg/ml, 10mg/ml and 5mg/ml). Larval mortality was assessed after 24, 48 and 72 hours. The chemical characterization of the oil showed the presence of carvacrol compounds (51.4%), as the majority constituent, followed by timol (15.6%), ρ-cimene (12,2%) and γ-terpinene (7,4%). These chemical compounds are reported in the literature as present in the composition of L. grata plants and responsible for the bioactivity evaluated. Larvicide trials showed that larvae mortality occurred in all concentrations and that there were diferences in impact among the two mosquito species, where A. aegypti was shown to be more sensitive to the effects of L. grata essential oil compounds than A. albopictus. Thus, we experimentally show that L. grata essential oil can be considered an option for the control of A. aegypti and A. albopictus.