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Neem oil based nanopesticide as an environmentally-friendly formulation for applications in sustainable agriculture: An ecotoxicological perspective

Pascoli, Mônica, Jacques, Mauricio T., Agarrayua, Danielle A., Avila, Daiana S., Lima, Renata, Fraceto, Leonardo F.
The Science of the total environment 2019 v.677 pp. 57-67
Allium cepa, Azadirachta indica, Caenorhabditis elegans, DNA, active ingredients, azadirachtin, biopesticides, corn protein, denitrification, ecotoxicology, enzymes, genes, genetic analysis, human health, microorganisms, nanocarriers, nanoparticles, neem oil, nitrogen fixation, nontarget organisms, organic production, pharynx, physicochemical properties, plant protection, protein synthesis, risk, sustainable agriculture, toxicity, toxicity testing, trees, zein
Sustainable agriculture encourages practices that present low risks to the environment and human health. To this end, zein (corn protein) can be used to develop nanocarrier systems capable of improving the physicochemical properties of biopesticides, reducing their possible toxicity. Neem oil extracted from the Azadirachta indica tree contains many active ingredients including azadirachtin, which is the active ingredient in multiple commercially available biopesticides. In this study, we describe the preparation and characterization of neem oil-loaded zein nanoparticles, together with evaluation of their toxicity towards nontarget organisms, using Allium cepa, soil nitrogen cycle microbiota, and Caenorhabditis elegans aiming to achieve the safer by design strategy. The spherical nanoparticles showed an average diameter of 278 ± 61.5 nm 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. These neem oil-loaded zein nanoparticles showed promising results in the toxicity studies, opening perspectives for its use in crop protection in organic agriculture.