Browsing by Author "Almeida, Miguel Peixoto de"
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- Acetylated cashew gum-based nanoparticles for the incorporation of alkaloid epiisopiloturinePublication . Rodrigues, Jessica do Amaral; Araújo, Alyne Rodrigues de; Pitombeira, Nadia Aline; Plácido, Alexandra; Almeida, Miguel Peixoto de; Veras, Leiz Maria Costa; Delerue-Matos, Cristina; Lima, Filipe Camargo Dalmatti Alves; Neto, Augusto Batagin; Paula, Regina Célia Monteiro de; Feitosa, Judith Pessoa Andrade; Eaton, Peter; Leite, José Roberto Souza A.; Silva, Durcilene Alves daThe natural alkaloid epiisopiloturine has recently become the focus of study for various medicinal properties, particularly for its anti-inflammatory and antischistosomal effect. The incorporation of active molecules in natural polymeric matrices has garnered increasing interest during recent decades. A new derivative of cashew gum successfully obtained by gum acetylation has shown great potential as a carrier in controlled drug release systems. In this work, epiisopiloturine was encapsulated in acetylated cashew gum nanoparticles in order to increase solubility and allow slow release, whereas the morphology results were supported by computer simulations. The particles were produced under a variety of conditions, and thoroughly characterized using light scattering and microscopic techniques. The particles were spherical and highly stable in solution, and showed drug incorporation at high levels, up to 55% efficiency. Using a dialysis-based in vitro assay, these particles were shown to release the drug via a Fickian diffusion mechanism, leading to gradual drug release over approximately 6 h. These nanoparticles show potential for the use as drug delivery system, while studies on their potential anti-inflammatory action, as well as toxicity and efficacy assays would need to be performed in the future to confirm their suitability as drug delivery candidates.
- Identification of Eschweilenol C in derivative of Terminalia fagifolia Mart. and green synthesis of bioactive and biocompatible silver nanoparticlesPublication . Araujo, Alyne Rodrigues de; Ramos-Jesus, Joilson; Oliveira, Taiane Maria de; Carvalho, Andressa Maria A. de; Nunes, Paulo Humberto M.; Daboit, Tatiane Caroline; Carvalho, Ana P.; Barroso, M. Fátima; Almeida, Miguel Peixoto de; Plácido, Alexandra; Rodrigues, Artur; Portugal, Camila C.; Socodato, Renato; Relvas, João B.; Delerue-Matos, Cristina; Silva, Durcilene Alves da; Eaton, Peter; Leite, José Roberto de Souza de A.A green synthetic route was developed to prepare silver nanoparticles (AgNPs) in aqueous solution for biological applications. Eschweilenol C, a compound derivative ellagic acid was identified as the main constituent of the aqueous fraction of the ethanolic extract of Terminalia fagifolia Mart. by NMR analysis. In the green synthesis, the ethanolic extract of T. fagifolia and its aqueous fraction were used to promote silver reduction and nanoparticle stabilization. The synthesized AgNPs presented a spherical or polygonal morphology shape by TEM analysis and AgNPs showed high levels of antioxidant and considerable antibacterial and antifungal activities. Synthesized nanoparticles presented significant antioxidant activity by sequestration of DPPH and ABTS radicals, in addition to iron reduction (FRAP assay) and measurement of antioxidant capacity in ORAC units, in addition, AgNP synthesized with the aqueous fraction also demonstrated antioxidant potential in microglial cells. Gram-positive and Gram-negative bacteria were susceptible to growth inhibition by the nanoparticles, among which the AgNPs formed by the ethanolic extract was the most effective. The data obtained by AFM images suggested that AgNPs could lead to the lysis of bacteria and subsequent death. The antifungal assays showed high efficiency against yeasts and dermatophytes. This work represents the first description of antifungal activity by AgNPs against Fonsecaea pedrosoi, the etiologic agent of chromoblastomycosis. In relation to biocompatibility, the AgNPs induced lower haemolysis than AgNO3.