ABSTRACT
ABSTRACT Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.
Subject(s)
Animals , Phenols/pharmacology , Aedes/drug effects , Insecticides/pharmacology , Phenols/isolation & purification , Phenols/toxicity , Phenols/chemistry , Time Factors , Insecticides/chemical synthesis , Insecticides/toxicity , Larva/drug effects , Lethal Dose 50ABSTRACT
ABSTRACT Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II) and L-glutamate-Cu (II) complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectroscopy and potentiometric titration. The toxicity of these complexes was analyzed in Aedes aegypti (Diptera: Culicidae) larvae and Gram-negative and Gram-positive bacteria. The interaction between the ligands and the amino acid balance and the distribution of the species as a function of pH were discussed. The lethal concentration median (LC50) for Ae. aegypti larvae were: L-glutamic acid-Cu (II) - 53.401 mg L-1 and L-aspartate-Cu (II) - 108.647 mg L-1. The minimum inhibitory concentration (MIC) required for Staphylococcus aureus and Escherichia coli was: L-glutamate-Cu (II) 500-2000 mg L-1 and L-aspartate-Cu (II) 1000-2000 mg L-1. The concentrations demonstrated toxicity that evidence the potential of the complexes as bactericide and insecticide. Metal complexes formed by amino acids and transition metals are advantageous because of low environmental toxicity, biodegradability and low production cost.
Subject(s)
Animals , Staphylococcus aureus/drug effects , Aspartic Acid/chemistry , Glutamic Acid/chemistry , Copper/chemistry , Aedes/drug effects , Escherichia coli/drug effects , Toxicity Tests , Larva/drug effects , Lethal Dose 50ABSTRACT
A test-chamber (K&L-Chamber) made of cardboard and acrylic plastic, and consisting in four sections (A, B, C and D) was developed by Klowden & Lea (1978) for Aedes aegypti host-seeking behavior studies. Later, Foster & Lutes (1985) also used an identical chamber to successfully evaluate the efficacy of electronic repellers. It was described here a modified K&L-Chamber for behavioral studies of Ae. aegypti adults. The chamber was made in polystyrene, consisting of three sections (A, B and C) and using a human hand and a fluorescent lamp as stimulus to attract the mosquitoes. The suitability of the present test-chamber was validated assaying 80 replicates and releasing 10 Ae. aegypti females in each replicate. The females were released in the section A and allowed to fly to the section C. A mean of 96.0 percent (s.e. 0.213) Ae. aegypti females successfully reached section C. The present test-chamber is cheaper and easier to handle and as efficient as K&L-Chamber, when compared to Foster & Lutes (1978) that noticed 93.8 percent of Ae. aegypti reaching the trap section.
Uma câmara-teste (Câmara K&L) feita de papelão e plástico acrílico, e consistindo em quatro seções (A, B, C e D) foi desenvolvida por Klowden & Lea (1978) para estudos sobre o comportamento de busca pelo hospedeiro por Aedes aegypti. Foster & Lutes (1985) também usaram uma câmara idêntica para, com sucesso, avaliar a eficácia de repelentes eletrônicos. Aqui foi descrita uma Câmara K&L modificada (Câmara K&L-Unicamp) para estudos comportamentais com adultos de Ae. aegypti. A câmara foi feita com isopor, consistindo em três seções (A, B e C) e usando uma mão humana e uma lâmpada fluorescente para atrair os mosquitos. A adequação da presente câmara-teste foi validada por meio de 80 repetições, cada uma com liberação de 10 fêmeas de Ae. aegypti. As fêmeas foram liberadas na seção A e permitidas voar para a seção C. Uma média de 96,0 por cento (e.p. 0,213) de fêmeas de Ae. aegypti chegaram a seção C. A Câmara K&L - Unicamp é de menor custo, mais fácil de manusear e é tão eficiente quanto a Câmara K&L, quando comparado a Foster & Lutes (1978) que descreveram que 93,8 por cento de Ae. aegypti chegaram a seção armadilha.