Avaliação do potencial tóxico de dois metalo-inseticidas em organismos não alvos
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Data
2016-07-15
Autores
Souza, Raphael Bastão de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A crescente utilização de agrotóxicos com o intuito de aumentar a produção agrícola tornou-se um dos principais problemas em relação ao meio ambiente. O solo é o primeiro compartimento a receber estas substâncias e, portanto, os organismos que nele habitam são os mais prejudicados pela sua aplicação. Com o intuito de proteger a biodiversidade do planeta, a comercialização e utilização de muitos agrotóxicos com reconhecida ação tóxica a organismos não-alvos têm sido proibidas por diversos países e organizações internacionais. Para substituí-los de forma eficaz, novos produtos têm sido desenvolvidos. As substâncias testadas no presente estudo, [Mg(5-Cl-phen)(hesperitina)(H2O)2](CH3COO) e [Mg(5-metil-phen) (hesperitina)(H2O)2](CH3COO), foram desenvolvidas como uma alternativa ao formicida sulfluramida, amplamente utilizado no combate às formigas cortadeiras e proibido em muitos países. Estas substâncias são complexos metálicos, compostos por um produto natural extraído de frutos cítricos, o flavonóide hesperitina, ligado a um metal. Neste sentido, o presente trabalho teve como objetivo investigar a toxicidade destas duas formulações de metalo-inseticidas para organismos não-alvo. Vegetais superiores, Allium cepa e Tradescantia pallida, e invertebrados terrestres, Rhinocricus padberdi, Eisenia fetida, Enchytraeus crypticus e Folsomia candida, foram utilizados como organismos bioindicadores na realização dos bioensaios. A avaliação da toxicidade foi realizada pela análise de diferentes parâmetros, como aberrações cromossômicas e micronúcleo, alterações histológicas e histoquímicas, indução de proteínas de estresse HSP70, testes de mortalidade e reprodução. Por meio dos testes citogenéticos aplicados em A. cepa e T. pallida, foi possível observar que o metalo-inseticida [Mg(5-metil-phen)(hesperitina)(H2O)2](CH3COO) foi capaz de induzir aberrações cromossômicas e formação de micronúcleo, principalmente em A. cepa. A análise morfológica realizada no intestino médio do diplópodo R. padbergi não apresentou alterações estatisticamente significativas, indicando que os metalo-inseticidas são seguros para a espécie. Porém, a análise das proteínas de estresse revelou que os compostos podem induzir a síntese de HSP70. O composto [Mg(5-metil-phen)(hesperitina)(H2O)2](CH3COO) não é capaz de gerar mortalidade em minhocas da espécie E. fetida nem interferir na sua reprodução, embora interfira na reprodução de enquitréideos da espécie E. cryptus e da espécie de colêmbolos F. candida, uma vez que diminuiu a geração de juvenis, principalmente nas maiores concentrações. Deste modo, sugere-se que o metalo-inseticida [Mg(5-metil-phen) (hesperitina)(H2O)2](CH3COO) apresenta maior potencial tóxico quando comparado ao metalo-inseticida [Mg(5-Cl-phen)(hesperitina)(H2O)2](CH3COO).
The great use of pesticides in order to increase agricultural production has become a major problem to the environment and has concerned scientists worldwide. These substances reach primarily the soil and the organisms that inhabit it are the most affected by its implementation. In order to protect the planet's biodiversity, the commercialization and use of many pesticides with known toxic effects to non-target organisms have been banned by many countries and international organizations. In order to effectively replace them, new products have been developed. The substances tested in this study were developed to replace the sulfluramide formicide, widely used against leaf cutting ants and banned in many countries. These new substances are metal complexes consisting of a natural product, the flavonoid hesperetin, linked to an inorganic metal. Among the developed formulations, [Mg(5-Cl-phen)(hesperetin)(H2O)2](CH3COO) and [Mg(5-methyl-phen)(hesperetin)(H2O)2](CH3COO) were the ones which showed better insecticide efficacy. In this sense, the present study aimed to investigate the toxicity of these two new formulations of metal-insecticides to non-target organisms. Higher plants, Allium cepa and Tradescantia pallida, and terrestrial invertebrates, Rhinocricus padberdi, Eisenia fetida, Enchytraeus crypticus and Folsomia candida were choosen as bioindicators organisms. The toxicity evaluation was carried out by analyzing different parameters, such as chromosomal aberrations and micronucleus induction, histological and histochemical alterations, induction of HSP70 stress protein, mortality and reproduction. Cytogenetic tests in A. cepa and T. pallida revealed that the complex [Mg(5-methyl-phen)(hesperetin) (H2O)2](CH3COO) is able to induce chromosomal aberrations and induction of micronucleus, particularly in A. cepa. Morphological analysis performed with the millipede R. padbergi showed no statistically significant changes, indicating that the complexes are safe for the species. However, the analysis of stress proteins revealed that the compounds can induce the synthesis of HSP70. The compound [Mg(5-methyl-phen)(hesperetin)(H2O)2](CH3COO) is not able to cause mortality in E. fetida worms neither change its reproduction rates, but interferes in the reproduction of the species E. cryptus and F. candida, once a decreased generation of juveniles was observed, especially in the highest concentrations. Thus, it can be suggested that [Mg(5-methyl-phen)(hesperitin)(H2O)2] (CH3COO) complex shows higher potential toxicity when compared to [Mg(5-Cl-phen)(hesperitin)(H2O)2](CH3COO).
The great use of pesticides in order to increase agricultural production has become a major problem to the environment and has concerned scientists worldwide. These substances reach primarily the soil and the organisms that inhabit it are the most affected by its implementation. In order to protect the planet's biodiversity, the commercialization and use of many pesticides with known toxic effects to non-target organisms have been banned by many countries and international organizations. In order to effectively replace them, new products have been developed. The substances tested in this study were developed to replace the sulfluramide formicide, widely used against leaf cutting ants and banned in many countries. These new substances are metal complexes consisting of a natural product, the flavonoid hesperetin, linked to an inorganic metal. Among the developed formulations, [Mg(5-Cl-phen)(hesperetin)(H2O)2](CH3COO) and [Mg(5-methyl-phen)(hesperetin)(H2O)2](CH3COO) were the ones which showed better insecticide efficacy. In this sense, the present study aimed to investigate the toxicity of these two new formulations of metal-insecticides to non-target organisms. Higher plants, Allium cepa and Tradescantia pallida, and terrestrial invertebrates, Rhinocricus padberdi, Eisenia fetida, Enchytraeus crypticus and Folsomia candida were choosen as bioindicators organisms. The toxicity evaluation was carried out by analyzing different parameters, such as chromosomal aberrations and micronucleus induction, histological and histochemical alterations, induction of HSP70 stress protein, mortality and reproduction. Cytogenetic tests in A. cepa and T. pallida revealed that the complex [Mg(5-methyl-phen)(hesperetin) (H2O)2](CH3COO) is able to induce chromosomal aberrations and induction of micronucleus, particularly in A. cepa. Morphological analysis performed with the millipede R. padbergi showed no statistically significant changes, indicating that the complexes are safe for the species. However, the analysis of stress proteins revealed that the compounds can induce the synthesis of HSP70. The compound [Mg(5-methyl-phen)(hesperetin)(H2O)2](CH3COO) is not able to cause mortality in E. fetida worms neither change its reproduction rates, but interferes in the reproduction of the species E. cryptus and F. candida, once a decreased generation of juveniles was observed, especially in the highest concentrations. Thus, it can be suggested that [Mg(5-methyl-phen)(hesperitin)(H2O)2] (CH3COO) complex shows higher potential toxicity when compared to [Mg(5-Cl-phen)(hesperitin)(H2O)2](CH3COO).
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Palavras-chave
Ecologia animal, Ecotoxicologia, Genotoxicidade, Histopatologia, Proteína de estresse, Teste de reprodução, Invertebrados de solo, Genotoxicity, Histopathology, Stress protein, Reproduction