Avaliação do potencial químico e biológico do óleo essencial de Virola theiodora (Myristicaceae) frente a ovos, larvas e adultos de Aedes aegypti (Diptera: Culicidae)

Abstract

Aedes aegypti is an important vector of arboviruses, including dengue, Zika, chikungunya, and urban yellow fever, and its control still relies largely on chemical insecticides. In this context, plant-derived essential oils have been investigated as sources of bioactive compounds with insecticidal potential. This study aimed to evaluate the chemical and biological potential of the essential oil from leaves of Virola theiodora against eggs, larvae, and adults of Aedes aegypti. The essential oil was obtained by hydrodistillation, including continuous extraction and fractionated extractions at one-hour intervals, and its chemical composition was analyzed by gas chromatography coupled to mass spectrometry. Ovicidal, larvicidal, and adulticidal bioassays were performed, together with a preliminary toxicity assessment against Artemia salina. In addition, the main constituents were evaluated through in silico ADMET profiling and molecular docking against the sterol carrier protein AeSCP-2 from A. aegypti. The essential oil obtained by continuous extraction showed an approximate yield of 0.4% and a chemical profile mainly characterized by β-pinene, α-pinene, trans-caryophyllene, D-limonene, and caryophyllene oxide. In the bioassays, the essential oil showed strong adulticidal activity, with an LC₅₀ of 8.73 µg/mL after 72 hours, high larvicidal activity, with an LC₅₀ of 28.05 µg/mL after 24 hours, and moderate ovicidal activity, with an LC₅₀ of 119.43 µg/mL after 120 hours of exposure. The hourly fractions showed compositional and biological variation, with the highest larvicidal activity observed for the third-hour fraction. Morphological observations indicated damage to treated eggs and larvae, whereas adult females showed no apparent morphological alterations. Molecular docking indicated higher predicted affinity of β-elemene and trans-caryophyllene for AeSCP-2, suggesting a possible contribution of these sesquiterpenes to the observed activity. However, the essential oil showed high toxicity against A. salina, indicating the need for further studies on selectivity and safety. Overall, the results demonstrate that V. theiodora is a promising source of bioactive constituents for the development of natural alternatives for A. aegypti control, although its application requires additional studies on formulation, ecotoxicity, and chemical standardization.