Folhas de Eugenia spp. como fonte de óleos essenciais com atividade larvicida sobre Aedes aegypti

Abstract

As a vector for several distinct diseases, the Aedes aegypti mosquito is an invasive species in Brazil that originated on the African continent, it poses a public health problem due to its short life cycle and its ability to adapt to chemical insecticides over successive generations. As an alternative, control can be achieved using bioinsecticides made from essential oils (EO’s), compounds derived from plants, which, in addition to being biodegradable, are complex structures that make it difficult for the larvae to adapt when exposed to them. Belonging to the Myrtaceae family, the genus Eugenia is known for producing essential oils with larvicidal activity; therefore, the objective of this study is to analyze the efficacy of essential oils from the species Eugenia azeda and Eugenia luschnathiana compared to Eugenia uniflora, which is known for its high larval lethality. To this end, the methodology employed involved collecting plants at the Federal University of Ceará, Pici Campus, in Fortaleza and in Aquiraz, in the state of Ceará, and extracting the essential oils by steam distillation using a Clevenger-type apparatus. The results show that the 50% lethal concentration (LC50) of E. uniflora (12.602 ± 1.783 μg/mL, and 8.5075 ± 0.528 μg/mL, at 48 hours) and E. azeda (27,13467 ± 1,322 μg/mL over 24 hours, and 17,46333 ± 1,508 μg/mL over 48 hours) were statistically identical during the 24- and 48-hour exposure periods, but both were higher than those of E. luschnathiana (60,93233 ± 6,093 μg/mL over 24 hours, and 35,17367 ± 6,583 μg/mL over 48 hours). Regarding the 90% Lethal Concentration (LC90) over the 24-hour period, the most lethal species was E. uniflora (23,92 ± 1,015 μg/mL), while the other species did not differ statistically from one another. However, over the 48-hour period, E. azeda (35,098 ± 2,596 μg/mL) showed increased lethality, becoming statistically equivalent to E. uniflora (20,824 ± 3,164 μg/mL) while E. luschnathiana (57,03267 ± 3,280 μg/mL) remained lower in terms of lethality. Finally, this study concludes that the most lethal essential oil for the larvae is that of E. uniflora, followed by E. azeda, with E. luschnathiana being the least lethal.