DEFAR - Departamento de Farmácia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/530

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2021 - 20232

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Autor: search.filters.author.Araújo, Raquel SilvaAssunto: search.filters.subject.Nanotechnology

Resultados da Pesquisa

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    Nanoemulsion of Ocotea indecora (Shott) Mez essential oil : larvicidal effects against Aedes aegypti .
    (2023) Machado, Francisco Paiva; Andrade, Diogo Folly Gomes; Salas Enríquez, Jairo Jhonatan; Mello Neto, Cícero Brasileiro de; Esteves, Ricardo dos Santos; Araújo, Raquel Silva; Toledo, Pedro Felipe Seguro de; Mantilla Afanador, Javier Guillermo; Santos, Marcelo Guerra; Oliveira, Eugênio Eduardo de; Ricci Junior, Eduardo; Rocha, Leandro Machado
    The widespread use of insecticide can lead to the resistance of the Aedes aegypti mosquito and adverse effects on non-target organisms, such as humans, other animals, and insects. In this sense, nanotechnology associated with natural products is a promising alternative to obtaining safer and more sustainable insecticide formulations against this vector. Therefore, in this research, we developed and optimized a nanoemulsion with essential oil from Ocotea indecora (Shott) Mez leaves and evaluated its larvicidal properties against Ae. aegypti larvae. In addition, oral toxicity assays were performed to test the nanoemulsion safety of the non-target organism Apis mellifera. The major constituent found was sesquirosefuran (81.4 %). The nanoemulsions were prepared by the low-energy method by phase inversion and characterized by the dynamic light scattering technique. The most suitable surfactant mixture was in hydrophilic-lipophilic balance 14.22, presenting droplets size of 122.8 nm and polydispersity index of 0.262. Then a 23 factorial design was realized to optimize the formulation suggesting the variables conditions of 1:1 of essential oil (5 % w/w) and surfactants at 500 rotations per minute. This led to spherical nanoemulsions with mean size and PdI of 105.3 nm and 0.263, respectively. The optimized nano- emulsion presented stability when stored at room temperature and refrigerated for up to one year. The LC50 values against Ae. aegypti larvae were 61.4, and 26.8 μg/mL after, 48, and 144 h, respectively. Scanning electron micrography showed morphological body alterations on the larvae Ae. aegypti treated with the nanoemulsion. Regarding the ecotoxicological evaluation, the nanoemulsion showed no toxicity against Apis mellifera. There- fore, this work demonstrated a simple method to obtain O. indecora nanoemulsion as an environmental-friendlier alternative to the Aedes aegypti control.
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    Nano-emulsions of the essential oil of Baccharis reticularia and its constituents as eco-friendly repellents against Tribolium castaneum.
    (2021) Lima, Luana A.; Sá, Paula S. Ferreira; Garcia Júnior, Manoel Daltro Nunes; Pereira, Vera Lúcia P.; Carvalho, José Carlos Tavares; Rocha, Leandro; Fernandes, Caio Pinho; Souto, Raimundo Nonato Picanço; Araújo, Raquel Silva; Botas, Gisele da Silva; Cruz, Rodrigo Alves Soares
    Nanoproducts based on natural products have been studied as ecologically and economically sustainable alter- natives for crop pest control. Baccharis reticularia DC. is a shrub endemic to Brazil, which leaves are traditionally used in aromatic medicinal baths. This study aims to evaluate the repellent activities of nano-emulsions con- taining the B. reticularia phytochemically characterized essential oil and some of its monoterpene constituents (limonene, α-pinene, and β-pinene) against Tribolium castaneum (Herbst). Essential oil was obtained by hydro- distillation of fresh leaves and stems and yielded 0.28 % (w/w). The main constituents of the essential oil were: limonene (14.6 %), β-myrcene (12.6 %), and bicyclogermacrene (12.5 %). The required hydrophile-lipophile balance (rHLB) of the nano-emulsions were: 13 (α-pinene) and 15 (essential oil, limonene, and β-pinene). All nano-emulsions showed mean droplet sizes bellow 200 nm and remain stable, at least, for 28 days (limonene), 90 days (β-pinene), or 150 days (essential oil and α-pinene). All nano-emulsions exhibited repellent activity against T. castaneum at 8.8 μg/cm2 . Limonene and α-pinene were the most active nano-emulsions, showing significant repellent action at 1.1 μg/cm2 , which indicates that these compounds contribute to the repellent action of the essential oil of B. reticularia. The present study opens perspectives for the utilization of B. reticularia essential oil and its constituents as raw material of new promising nanopesticides produced using a low energy, solvent-free and ecofriendly method. Thus, this work contributes significantly to the search for new ecologically correct strategies for the control of T. castaneum.