Actividad biológica de los aceites de semillas de Annona muricatay A. cherimola / Biological activity of Annona muricata and A. cherimola seed oils

Vegetable extracts have become important raw materials for food, pharmaceutical and cosmetic industries because of their biological potential. The objective of this study was to assess the biological activity of vegetable oils (VOs) extracted from Annona muricata and A. cherimola. Antibacterial activity was determined by plaque microdilution. The assessment of hemolytic inhibition and morphological alterations was performed in erythrocyte cultures by spectrophotometry and microscopy, respectively. Neutrophils were used to analyze both cytotoxicity by the trypan blue exclusion method and the effect on gelatinase granule release (MMP9) via zymography. Whereas VOs showed a mild antibacterial activity (900 µL/mL) on five ATCC bacterial strains, they had no effect on multi-resistant bacteria. In addition, VOs inhibited hydrogen peroxide induced hemolysis and did not cause erythrocyte cell abnormalities. Cytotoxicity was not detected in neutrophils and VOs were able to stimulate MMP9 release. These results support their potential use by the food and cosmetic industries due to their antioxidant, non-cytotoxic, and slight antibacterial capacities.

Los extractos vegetales adquieren importancia en la industria alimentaria, farmacéutica y cosmética, por su potencial biológico. El objetivo de este estudio fue evaluar actividad biológica de los Aceites Vegetales (AV) de semillas de Annona muricata y A. cherimola. La actividad antibacteriana se determinó mediante microdilución en placa; en cultivo de eritrocitos se evaluó inhibición hemolítica por espectrofotometría y alteraciones morfológicas por recuento microscópico; en neutrófilos se evaluó citotoxicidad por método de exclusión con azul de tripán, y el efecto sobre liberación de gránulos de gelatinasa (MMP9) mediante zimografía. Los AV presentaron actividad antibacteriana leve (900 µL/mL) en cinco cepas ATCC, pero no en bacterias multirresistentes; inhibieron la hemolisis inducida por peróxido de hidrogeno; no generaron deformaciones eritrocitarias; no se evidenció citotoxicidad en neutrófilos y estimularon la liberación de MMP9. Los resultados podrían sustentar el uso potencial de estos AV en la industria alimenticia o cosmética, gracias a su capacidad antioxidante, no citotóxica y levemente antibacteriana.

Nanopartículas de óxidos de ferro e nióbio com diferentes recobrimentos: síntese, caracterização e avaliação do potencial biológico / Iron oxide nanoparticles with different coatings and niobium oxide nanoparticles: synthesis, characterization and assessment of biological potential

Nanopartículas (NPs) tem ganhado notoriedade crescente em aplicações biomédicas. Podendo ser constituídas de diversos materiais, NPs tem sido empregadas como agentes de contraste, na liberação direcionada e controlada de fármacos, em terapia para tratamento de câncer, em catálise heterogênea, entre outras aplicações. As nanopartículas magnéticas de óxido de ferro (MNP) destacam-se pela multiplicidade de aplicações, apesar de serem pouco caracterizadas quanto à toxicidade celular. Outras nanopartículas com excelente potencial são as constituídas de óxido de nióbio (NbONPs), as quais merecem atenção especial, pois o Brasil é detentor de 98% das reservas comercialmente viáveis deste elemento. Neste trabalho NPs destes dois metais de transição (ferro e nióbio) foram sintetizadas, almejando entender suas interações com materiais, biomoléculas e meios biológicos. Diversas metodologias foram desenvolvidas e testadas com intuito de otimizar a morfologia e o rendimento da preparação, resultando na escolha de decomposição térmica para MNP e, para NbONPs, escolheu-se a impregnação do óxido de nióbio sobre uma matriz de MNPs recobertas com sílica. No caso das MNPs, procedeu-se ao recobrimento das mesmas com lipídeos zwitteriônicos (Dioleilfosfatidilcolina (DOPC)) e carregados positivamente (Brometo de dioctadecildimetilamônio (DODAB)). Foram inicialmente caracterizadas as suas propriedades em diversos ambientes biológicos para posteriormente realizarmos ensaios de citoxicidade em queratinócitos humanos (HaCaT). Avaliamos também a degradação das NPs em diferentes pH, bem como, a interação das mesmas com membranas miméticas de vesículas gigantes unilamelares (GUVs - Giant Unilamellar Vesicles), com visualização microscópica. As MNPs recobertas com DODAB mostraram-se mais tóxicas para os queratinócitos em cultura e também causaram lise das GUVs. No caso das NbONPs, avaliou-se a acidez proveniente do Nb2O5 e o seu potencial em catálise heterogênea, bem como a avaliação da citotoxicidade em HaCaT revelou um potencial uso biomédico

Nanoparticles (NPs) have received increasing attention in biomedical applications. NPs can be constituted by different materials and have been used as contrast agents, in drug delivery, in cancer therapy, in heterogeneous catalysis, among other applications. Magnetic iron oxide nanoparticles (MNP) are notable for their multiplicity of applications, although they are poorly characterized for cellular toxicity. Other nanoparticles with excellent potential are made of niobium oxide (NbONPs), which deserve special attention, since Brazil holds 98% of the commercially viable reserves of this element. In this Thesis, NPs of these two transition metals (iron and niobium) were synthesized, aiming to understand their interactions with materials, biomolecules and media biological. Several methodologies were developed and tested to optimize the morphology and yield of the preparation, resulting in the choice of thermal decomposition for MNPs and, for NbONPs, the impregnation of niobium oxide on a matrix of silica-coated MNPs. In the case of MNPs, they were also coated with lipid zwitterionics (Dioleoyl phosphocholine (DOPC)) and positively charged (Dimethyldioctadecylammonium bromide (DODAB)) lipids. Its properties were initially characterized in several biological environments for later cytotoxicity assays in human keratinocytes (HaCaT). It evaluated the degradation of the NPs in different pH, as well as their interaction with giant unilamellar vesicle (GUVs) mimetic membranes, with microscopic visualization. MNPs coated with DODAB were more toxic to keratinocytes in culture and caused lysis of GUVs. In the case of NbONPs, acidity from Nb2O5 was evaluated in heterogeneous catalysis, as well as the evaluation of HaCaT cytotoxicity revealed a potential biomedical use