Avaliação da toxicidade e atividade biológica de nanopartículas de zeína contendo o biocida azadiractina
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Data
2019-09-02
Autores
Pascoli, Mônica
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Universidade Estadual Paulista (Unesp)
Resumo
Para o controle de pragas, contínuamente se faz o uso de elevadas quantidades de agroquímicos que muitas vezes possuem efeitos adversos tanto para o ambiente quanto para a saúde humana. Este fato tem motivado a busca por alternativas menos impactantes. Neste cenário, diversos mecanismos estão sendo estudados a fim de minimizar estes danos, como por exemplo, o desenvolvimento de sistemas carreadores utilizando polímeros biodegradáveis e proteínas. Aliado a isto, a utilização de inseticidas botânicos também tem demonstrado potencialidade para o combate a pragas, devido aos possíveis menores impactos causados por esses produtos de origem natural. Portanto, o presente trabalho descreve o preparo e caracterização de um nanobiopesticida baseado em nanopartículas de zeína carreadas com óleo de neem junto com a avaliação da sua toxicidade contra organismos não alvos (usando Allium cepa, microbiota do solo envolvida no ciclo do nitrogênio e Caenorhabditis elegans) e da sua fitotoxicidade (usando Phaseolus vulgaris). Ademais, a atividade biológica desse novo sistema em pragas agrícolas (Acanthoscelides obtectus, Bemisia tabaci and Tetranychus urticae) também foi investigada. As nanopartículas esféricas apresentaram diâmetro médio de 278 ± 61,5 nm, alta eficiência de encapsulação (> 80%) e boa estabilidade durante os experimentos. Nos ensaios de toxicidade com A. cepa, as nanopartículas de zeína carregadas com óleo de neem mitigaram o aumento do índice de danos relativo ao DNA causado pelo óleo de neem. A análise genética molecular da microbiota do solo envolvida no ciclo do nitrogênio revelou que as nanopartículas de zeína carreadas de óleo de neem não alteraram o número de genes que codificam enzimas fixadoras de nitrogênio e enzimas desnitrificantes. Em C. elegans, as nanopartículas de zeína carreadas com óleo de neem não tiveram efeito tóxico, enquanto o óleo de neem interferiu no bombeamento faríngeo e na expressão da proteína GST-4. Este novo sistema não causou nenhum efeito fitotóxico em P. vulgaris em tratamentos pré e pós-emergentes. O nanobiopesticida e o óleo de neem exibiram efeito inseticida sobre B. tabaci e T. urticae e o nanobiopesticida aumentou significativamente o efeito inseticida em A. obtectus comparado ao óleo de neem. Utilizando nanoformulações marcadas, foi possível identificar a exposição entre o nanobiopesticida e A. obtectus, principalmente por sua região ventral, com destaque para as pernas e partes bucais. Estas nanopartículas de zeína carreadas com óleo de neem mostraram resultados promissores como nanobiopesticida desenvolvido com a estratégia "safer by design" o que lhe confere grande potencialidade de uso no controle de pragas na agricultura sustentável, causando menores impactos ao meio ambiente e à saúde humana.
For pest control, large amounts of agrochemicals are continuously used which often have adverse effects on the environment and human health. This fact has motivated the search for less impacting alternatives. In this scenario, several mechanisms are being studied in order to minimize these damages, such as the development of carrier systems using biodegradable polymers and proteins. In addition, the use of botanical insecticides has also shown potential for pest control, due to the possible lower impacts caused by these products of natural origin. Therefore, the present work describes the preparation and characterization of a nanobiopesticide based on neem oil-loaded zein nanoparticles, together with evaluation of their toxicity towards nontarget organisms (using Allium cepa, soil nitrogen cycle microbiota, and Caenorhabditis elegans) and of their phytotoxicity (Phaseolus vulgaris). In addition the biological activity of this new system on agricultural pests (Acanthoscelides obtectus, Bemisia tabaci and Tetranychus urticae) were also carried out. The spherical nanoparticles showed an average diameter of 278 ± 61.5 nm, a high encapsulation efficiency (>80%) and a good stability during the experiments. In the toxicity assays with A. cepa, the neem oil-loaded zein nanoparticles mitigated the increase in the DNA relative damage index caused by the neem oil. Molecular genetic analysis of the soil nitrogen cycle microbiota revealed that neem oil-loaded zein nanoparticles did not change the number of genes which encode nitrogen-fixing enzymes and denitrifying enzymes. In C. elegans, the neem oil-loaded zein nanoparticles had no toxic effect, while neem oil interfered with pharyngeal pumping and GST-4 protein expression. Pre- and post-emergence treatments using this new system did not cause any phytotoxic effects towards P. vulgaris. The neem oil nanobiopesticide exhibited insecticidal effects on B. tabaci and T. urticae, while the effect against A. obtectus was significantly increased, compared to plain neem oil. Using labeled nanoformulations, it was possible to identify the exposure between nanobiopesticide and A. obtectus mainly by their ventral region with prominence to the legs and mouthparts. These neem oil-loaded zein nanoparticles showed promising results as a nanobiopesticide developed with the "safer by design" strategy which gives it great potential for use in pest control in sustainable agriculture, causing less impacts on the environment and human health.
For pest control, large amounts of agrochemicals are continuously used which often have adverse effects on the environment and human health. This fact has motivated the search for less impacting alternatives. In this scenario, several mechanisms are being studied in order to minimize these damages, such as the development of carrier systems using biodegradable polymers and proteins. In addition, the use of botanical insecticides has also shown potential for pest control, due to the possible lower impacts caused by these products of natural origin. Therefore, the present work describes the preparation and characterization of a nanobiopesticide based on neem oil-loaded zein nanoparticles, together with evaluation of their toxicity towards nontarget organisms (using Allium cepa, soil nitrogen cycle microbiota, and Caenorhabditis elegans) and of their phytotoxicity (Phaseolus vulgaris). In addition the biological activity of this new system on agricultural pests (Acanthoscelides obtectus, Bemisia tabaci and Tetranychus urticae) were also carried out. The spherical nanoparticles showed an average diameter of 278 ± 61.5 nm, a high encapsulation efficiency (>80%) and a good stability during the experiments. In the toxicity assays with A. cepa, the neem oil-loaded zein nanoparticles mitigated the increase in the DNA relative damage index caused by the neem oil. Molecular genetic analysis of the soil nitrogen cycle microbiota revealed that neem oil-loaded zein nanoparticles did not change the number of genes which encode nitrogen-fixing enzymes and denitrifying enzymes. In C. elegans, the neem oil-loaded zein nanoparticles had no toxic effect, while neem oil interfered with pharyngeal pumping and GST-4 protein expression. Pre- and post-emergence treatments using this new system did not cause any phytotoxic effects towards P. vulgaris. The neem oil nanobiopesticide exhibited insecticidal effects on B. tabaci and T. urticae, while the effect against A. obtectus was significantly increased, compared to plain neem oil. Using labeled nanoformulations, it was possible to identify the exposure between nanobiopesticide and A. obtectus mainly by their ventral region with prominence to the legs and mouthparts. These neem oil-loaded zein nanoparticles showed promising results as a nanobiopesticide developed with the "safer by design" strategy which gives it great potential for use in pest control in sustainable agriculture, causing less impacts on the environment and human health.
Descrição
Palavras-chave
Nanobiopesticida, Óleo de Neem, Nanotoxicidade, Fitotoxicidade, Atividade Biológica, Agricultura sustentável, Nanobiopesticide, Neem oil, Nanotoxicity, Phytotoxicity, Biological activity, Pest control, Sustainable agriculture