Avaliação da atividade larvicida de óleos essenciais de espécies de citrus frente às larvas de Aedes aegypti

Abstract

Considering the importance of the discovery of new substances that present larvicidal potential, this research aims to characterize chemically the essential oil of different lemon species (Common Lemon (Citrus x limon (L.) Osbeck), Limão Tanja (Citrus x sp) and Lemon Galego (Citrus x aurantifolia (Christm.) Swingle) and test the larvicidal activity against the larvae of the Aedes aegypti mosquito, thus controlling arboviruses such as Dengue, Zika, Chikungunya and Yellow Fever. The essential oil was extracted by steam entrainment technique in Clevenger apparatus. The chemical characterization of the essential oil was performed by Gas Chromatography coupled to Mass Spectrometer (GC-MS) and its larvicidal activity was performed against Aedes aegypti through techniques recommended by the World Health Organization (WHO). The larvicidal activity, based on the percentage of larval mortality, was evaluated after 24 hours of exposure to the treatments. The results for the yield of common lemon (2.45%), tanja (2.54%), Galician (2.29%) and the values of the physicochemical properties of the oils studied compared to the literature, can be observed that there is similarity between them, with respect to the analyzed parameters. Chromatographic analyzes show that essential oils present Limonene as the major constituent. In the bioassay of toxicity to Artemia salina, common lemon, tan and lime oils presented LC50 of 1032, 503.5 and 1843μg.mL-1, respectively, with 95% confidence interval (p <0.05). literature indicates that the extract is "non-toxic". Lemon essential oil Tanja (Citrus x sp) showed the highest larvicidal activity, with LC50 of 20.26μg.mL-1 and CL90 of 28.5μg.mL-1 followed by Common Lemon (Citrus x limon) with LC50 40.22 μg.mL-1 and CL90 of 68.88μg.mL-1. On the other hand, the essential oil of Lemon Galego (Citrus x aurantifolia) presented the lowest activity with LC50 of 69.71μg.mL-1 and CL90 of 115.3 μg.mL-1 with 95% confidence interval (p <0.05). The results indicate that the oils are tested as well as larvicidal properties for Aedes aegypti larvae.