Atividade larvicida de extratos de Annona Muricata encapsulados em cubossomos

Abstract

In recente years, the research for potential biolarvicides has received attention due to the negative effects caused by the use of synthetics insecticides over the years. The chemical insecticidal is one the methods used in control of Aedes aegypti mosquito, a vector for disease such as, dengue, yellow fever, chikungunya and zika. In this context, it Annona muricata (graviola) stands out which has larvicide potential due to the presence of polar acetogenins. The naturals larvicides needs significantly higher concentrations to induce death of the larvae. Therefore, one of the alternatives to decrease concentration is the employ of nanosystem. The cubossomes are known to exhibit controlled or sustained release of agents and the ability to incorporate molecules of different natures. For these reasons, the present work aims at investigate the lethal concentration (LC50) of different extracts incorporated in cubosomes against the Ae. Aegypti larvae. The samples were prepared containing different proportions of extract and cubosomes (E/C) by cosolubilization and addition methods to evaluate larvicidal activity. The results of larvicidal activity of the extracts demonstrated that only the ethanolic extract (EE) showed a larvicidal action. The incorporating of EE into cubosomes in different proportions, it was observed the high larvicidal activity of the samples prepared by the two methods, mainly the proportions obtained by addition. HPLC analyzes suggested the presence of acetogenins mainly in the EE, by the maximum absorption at a wave length of 214 nm, characteristic of acetogenins. The chromatograms also showed peaks with maximum absorption around 208 nm, this fact suggests that they are acetogenins that have α-β-unsaturated γ-lactonic ring. The DLS analyzes indicated that the systems obtained by cosolubilization had smaller particle sizes, a result corroborated by the NTA analysis. The analyzes such as NMR and SAXS will be carried out to complete the extracted and nanosystem study and to corroborate the results obtained in larvicidal tests and characterization analysis. These analyzes were not carried out due to limited access to laboratories during the pandemic.