Browsing by Author "Rosa, Juliana dos Santos"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Chemistry modification of PMMA-g-PEG copolymer.
    (2014) Rosa, Juliana dos Santos; Silveira, Benila Maria; Novack, Kátia Monteiro; Santos, Viviane Martins Rebello dos; Teixeira, Leonardo César de Moraes
    Copolymers are polymers consisting of different repeat units and their production is usually motivated by the changing of polymers properties. An important application are the transportation of drugs within the organism with the aim of controlling the release of the substance. The synthesis of these new copolymers is based on simple semi-synthesis and low cost. The synthetic routes are based on the interaction of the graft copolymer (PMMA-g-PEG) with a variety of reagents such as acetic anhydride, acetic acid, methyl iodide, sulfuric acid and hydrochloric acid. The products from these reactions of esterification, methylation, acetylation and halogenation will be characterized by Fourier-transforminfrared spectroscopy (FTIR). The use of this technique allowed us to detect the main absorption bands related to the C¼O bonds, C-Cl, R-COOR and CO, thus confirming the efficiency of modification reactions of the graft copolymer chain.
  • No Thumbnail Available
    Item
    Nanostructured systems improve the antimicrobial potential of the essential oil from cymbopogon densiflorus leaves.
    (2019) Seibert, Janaína Brandão; Rosa, Juliana dos Santos; Almeida, Tamires Cunha; Amparo, Tatiane Roquete; Rodrigues, Ivanildes Vasconcelos; Lanza, Juliane Sousa; Frezard, Frederic Jean Georges; Soares, Rodrigo Dian de Oliveira Aguiar; Teixeira, Luiz Fernando de Medeiros; Souza, Gustavo Henrique Bianco de; Vieira, Paula Melo de Abreu; Barichello, José Mario; Santos, Orlando David Henrique dos
    The physicochemical characteristics of nanostructured suspensions are important prerequisites for the success of new drug development. This work aimed to develop nanometric systems containing Cymbopogon densiflorus leaf essential oil and to evaluate their antimicrobial activity. The essential oil was isolated by hydrodistillation from leaves and analyzed by GC-MS. The main constituents were found to be trans-p-mentha-2,8-dien-1-ol, cis-p-mentha2,8-dien-1-ol, trans-p-mentha-1(7),8-dien-2-ol, cis-piperitol, and cis-p-mentha-1(7),8-dien-2-ol. In silico prediction analysis suggested that this oil possesses antimicrobial potential and the main mechanism of action might be the peptidoglycan glycosyltransferase inhibition. Nanoemulsions were prepared by the phase inversion method, and liposomes were made by the film hydration method. Qualitative evaluation of the antimicrobial activity was performed by the diffusion disk assay with 24 microorganisms; all of them were found to be sensitive to the essential oil. Subsequently, this property was quantified by the serial microdilution technique, where the nanoformulations demonstrated improved activity in comparison with the free oil. Bactericidal action was tested by the propidium iodide method, which revealed that free essential oil and nanoemulsion increased cytoplasmic membrane permeability, while no difference was observed between negative control and liposome. These results were confirmed by images obtained using transmission electron microscopy. This study has shown an optimization in the antimicrobial activity of C. densiflorus essential oil by a nanoemulsion and a liposomal formulation of the active substances.