Alterações morfo-histológicas em larvas de Aedes aegypti (linnaeus, 1762) (Diptera, Culicidae) causadas pelo tanino catéquico isolado da planta do cerrado Magonia pubescens (Sapindaceae)

Abstract

The control of Aedes aegypti is nowadays one of the major public health problemsin Brazil, being the main vector of dengue and urban yellow fever. Of Africanorigin, this mosquito is well adapted to Brazilian climatic conditions and is nowdistributed in all states. The usual methods to combat and control the mosquito havebeen highly questioned. The chemical insecticides currently used have led to theemergence of resistant populations of mosquitoes and the consequent increase ofits density, causing significant epidemics of dengue. Insecticides of botanical originhave shown to be alternative candidates to their control. This work presents forthe first time, morphohistologic changes caused by the larvicidal activity of tannincatechin extracted from Magonia pubescens on larvae of A. aegypti, showing thepotential of this natural larvicidal compound. Larvae of the 3rd stage were submittedto a water solution of tannin catechins, at 37ppm, where they remained for up to 24h. Larvae that reached lethargic state were collected and fixed in paraformaldehydeat 4%, in sodium cacodylate buffer at 0.1 M and pH 7.2, included in resin, mountedon slides, stained with hematoxylin-eosin and analyzed by light microscope. Themain cell toxic effects of tannin catechin on larvae of A. aegypti were the highvacuolation and absence of cytoplasmic limits, vesicular apical formation withrelease of cytoplasmic content, increase in intercellular spaces and detachment ofcells from the basal membrane.