Toxicidade do extrato etanólico de Magonia pubescens sobre larvas de Aedes aegypti

Abstract

Crude ethanol extracted from Magonia pubescens trunks was utilized to prove its effect in the intestinal tract of Aedes aegypti 3rd instar larvae. Exposure times (2, 4, 6, 8, 10, 12, and 13 hours) were tested to verify when the morphological alterations begin to occur, in the intestinal tract of the larvae. The toxic effect of the extract was mainly in the midgut, beginning at the anterior midgut and followed through to posterior midgut. The main alterations observed were partial or total cell destruction, high citoplasmatic vacuolization, increase of subperitrophic space, cell hypertrophy and the epithelium did not maintain its monolayer appearance. The alterations began after four hours of exposure to M. pubescens extract. Observations of tissue sections from larvae treated for different lengths of time revealed a wide variation in the degree of damage between exposure periods and midgut larvae region. The present study provides evidence regarding the mode of action of the M. pubescens extract and suggests its potential utilization as a larvicide to control Aedes aegypti mosquito.

Evaluation of embryotoxic and embryostatic effects of the aqueous extract of Rhizophora mangle and tannic acid on eggs and larvae of Aedes aegypti

“…Studies have shown that the major toxic effects caused by tannins in the mesenteron cells of larvae in the third instar of A. aegypti were: high cytoplasmic vacuolation, abscence of cytoplasmic limits, apical vesicle formation with the release of cytoplasmic contents of the cells, increased intercellular space and detached cells from the basement membrane. These results are similar to those histopathological processes reported in insects, in response to a variety of biological toxic substances (Abed et al 2007, Arruda et al 2003, Barreto et al 2006, Delphine et al 1999, Gusmão et al 2002, Rey et al 1999.…”

Effects of croton urucurana extracts and crude resin on Anagasta kuehniella (Lepidoptera: Pyralidae)

“…Other investigators, after evaluating the toxic effects of tannins on the fauna associated with Culicidae, suggested that the vegetable tannins can be useful as a complement in control programs of hematophagous species of mosquitoes associated with the human diseases. Studies carried out with the extracts of Magonia pubescens (Sapindaceae) provided evidence that the action mechanisms and morphological changes leading to the death in A. aegypti were similar to those of tannic acid (Arruda et al, 2003;Pautou et al, 2000;. Moreover, toxicological studies performed in the rabbits, mice and guinea pigs have proved to be atoxic, according to the rules for plant products.…”

Alterações ultraestruturais em larvas de Aedes aegypti submetidas ao diterpeno labdano, isolado de Copaifera reticulata (Leguminosae), e à uma fração rica em taninos de Magonia pubescens (Sapindaceae)

“…Isto seria consequência da intoxicação celular causada tanto pelo diterpeno quanto pelos taninos, levando à formação de vesículas e à lise celular. Efeitos similares foram obtidos com as plantas Alnus glutinosa, Magonia pubescens, Populus nigra e Quercus robur 11,25,26 .…”

“…Vários trabalhos sobre o efeito larvicida de diversas substâncias, em Diptera, relatam que as principais alterações morfohistológicas ocorrem no mesêntero, desta forma, fica claro o importante papel desta porção do tubo digestório no processo de absorção 1,11,12,25 . As alterações provocadas por estas substâncias, independente se são de origem química ou biológica, são sempre semelhantes.…”

“…Em busca de novas alternativas para o controle do Aedes aegypti, várias pesquisas vêm sendo desenvolvidas no intuito de encontrar um inseticida eficaz com menor impacto ambiental [11][12][13][14][15][16][17][18][19] .…”