Estudo das propriedades físicas e avaliação da atividade larvicida dos complexos metálicos de Rutina-Zn (II)

Abstract

Introduction: The Aedes aegypti mosquito has been a public health problem worldwide as one of the main transmitters of dengue, zika, chikungunya and yellow fever. The control of A. aegypti is realized mainly by the application of synthetic chemical pesticides, some with high toxicity, which has been caused adverse impacts on human health and damages on biodiversity. Therefore, natural products and their derivatives are being used in the control of A. aegypti larvae, thus, flavonoids arise as an alternative potential in the development of products for vector control. Objectives: In this sense, the objective of this work was to analyze the physical properties of complexes derived from rutin and to carry out the development of larvicidal activity against larvae of the Aedes aegypti mosquitoes. Methodology: Initially, the rutin-Zn (II) complex was synthesized mixing dropwise a methanolic solution of Zn(CH3OO)2.2H2O (0.4 mol.L-1) with a methanolic solution of rutin (0.1 mol L-1). The mixture was stirred at 300 rpm for 24h at a temperature of 37-40 °C and subsequently the complex was vacuum filtered. Then its physics properties were determined by FT-IR, UV-Vis, DRX and DLS spectroscopies. The larvicidal activity was evaluated against Aedes aegypti mosquito larvae by exposure to different concentrations of formulations containing the metal complexes compared to the free rutin in 24h and 48h. Results and discussion: FT-IR UV-Vis and DRX analyzes indicated the formation of a Rutin- Zn complex with possible binding sites in the system between the ring C carbonyl and the 5-OH group and the dihydroxyl groups 3'-OH and / or 4'-OH evidenced by chemical shifts observed in these measurements. The DLS study showed that the complexes presented higher average particle size and higher polydispersion index (Pdi) than the ligand, expected values due to formation of the complexes, these measurements indicated good homogeneity in the distribuition of the particle size of the Zn-rutin complexes. The data from the biological assay suggest that the complexes obtained an increase in larvicidal activity against Aedes aegypti larvae, presenting better LC50 and LC90 values for 24h and 48h compared to rutin. Conclusions: From the results obtained, it was possible to conclude that this work was promising for the study of new larvicidal agents based on flavonoid-metal, providing good perspectives for the control of larvae with an ecofriendly approach to the environment