Avaliação do potencial larvicida no controle de Aedes aegypti do óleo essencial e extratos brutos etanólico e aquoso das folhas de Tridax procumbens L

Abstract

Introduction: Tridax procumbens L., belongs to the Asteraceae and is commonly known as bull weed. Parts of the plant are used in folk medicine. Objective: To evaluate the antioxidant, cytotoxic and larvicidal potential of essential oil (EO) and crude ethanol extracts (EBE) from the leaves of T. procumbens, as well as to identify the main classes of secondary metabolites. Methodology: The antioxidant activity was evaluated by the sequestration method of the 2,2-diphenyl-1-picrylhydrazyl radical; Cytotoxic activity was assessed using A. salina; The microbiological activity of the extracts were performed by the microdilution method with bacteria Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The larvicidal bioassay was performed with larvae of the A. aegypti mosquito and the identification of the metabolites was performed by phytochemical tests, quantification of total phenolics for the extracts, and GC-MS for the oil. Results and discussion: Phytochemical analysis of the extracts showed the presence of depsidones and depsidones, flavanoids, phenols and tannins and alkaloids, proteins and amino acids, saponins. The phytochemical analysis of OE showed the presence of 20 compounds, being the main ones: thymol and γ-Terpinene. The microbiological results for the EBA were positive, and it was possible to identify the MIC and CBM, at the concentrations tested, for the three bacteria used. For the cytotoxic activity against A. salina presented low activity. EBA showed good larvicidal activity when compared to literature and EBE. OE presented antioxidant activity with IC50 of 194.51 μg.mL-1, demonstrating activity in the highest concentrations tested. It presented low cytotoxic activity against A. salina, with LC50 of 1238.67 μg.mL-1, demonstrating the toxicity of the oil tested. OE presented good larvicidal activity when compared to the literature, with LC50 = 79.0 μg.mL-1 in 24 hours and LC50 = 69.15 μg.mL-1 in 48 hours. Conclusion: It was possible to identify that both the EBA and EO of the leaves of T. procumbens present potential for the development of natural insecticides