Navegando por Autor "Trindade, Izabel Cristina"

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Estudo químico de extratos e frações de Maytenusimbricata Mart. ex. Reissek e de seus fungos endofíticos.
(2013) Trindade, Izabel Cristina; Vieira Filho, Sidney Augusto
Neste trabalho, teve-se como objetivo dar continuidade a estudos realizados com Maytenus imbricata. Durante o desenvolvimento do trabalho foram realizados experimentos envolvendo a purificação de frações obtidas através de fracionamento de extratos polares e apolares de Maytenus imbricata. O isolamento dos constituintes das folhas foi realizado utilizando-se métodos cromatográficos clássicos como cromatografia em coluna e cromatografia em camada delgada. A determinação estrutural foi realizada utilizando-se dados obtidos através de ressonância magnética nuclear de hidrogênio e de carbono (RMN de 1H e de 13C). Foi possível o isolamento e identificação de 5 constituintes pertencentes a classe dos triterpenos pentacíclicos. Foram realizados estudos inéditos com fungos endofíticos isolados de diferentes partes de M. imbricata. Os fungos foram cultivados com o objetivo de se obter extratos metanólicos e em acetato de etila. Os extratos foram submetidos a fracionamento através de Cromatografia Gasosa acoplada a Espectrômetro de Massas (CG-EM) e os constituintes isolados foram analisados através do banco de dados NIST. Foram identificados 27 constituintes de diferentes classes químicas. Os fungos também foram cultivados em lâminas para posterior identificação microscópica.
Lipid-based nanocarriers co-loaded with artemether and triglycerides of docosahexaenoic acid : effects on human breast cancer cells.
(2020) Lanna, Elisa Gomes; Siqueira, Raoni Pais; Machado, Marina Guimarães Carvalho; Souza, Aline de; Trindade, Izabel Cristina; Branquinho, Renata Tupinambá; Mosqueira, Vanessa Carla Furtado
Artemether (ART) was combined with triglyceride of docosahexaenoic acid (DHA) as the lipid-core in nano emulsions (NE), nanostructured lipid carriers (NLC), and PEG-PLA nanocapsules (NC) formulations, and their effects on human breast cancer cells were evaluated. ART has been extensively used for malaria and has also therapeutic potential against different tumor cells in a repositioning strategy. The concentration-dependent cytotoxicity in vitro was determined in tumor lineages, MDA-MB-231 and MCF-7, and non-tumor MCF-10A cells for free-ART/DHA combination and its formulations. The cells were monitored for viability, effects on cell migration and clonogenicity, cell death mechanism, and qualitative and quantitative cell uptake of nanocarriers. The lipid-nanocarriers showed mean sizes over the range of 110 and 280 nm with monodisperse populations and zeta potential values ranging from − 21 to − 67 mV. The ART encapsulation efficiencies varied from 57 to 83 %. ART/DHA co-loaded in three different lipid nanocarriers reduced the MDA-MB-231 and MCF-7 viability in a dose-dependent manner with enhanced selectivity toward tumor cell lines. They also reduced clonogenicity and the ability of cells to migrate showing antimetastatic potential in both cell lines and triggered apoptosis in MCF-7 cells. Confocal microscopy and flow cytometry analysis showed that NC, NLC, and NE were rapidly internalized by cells, with higher interaction displayed by NE with MCF-7 cells compared to NC and NLC that was correlated with the strongest NE-fluorescence in cells. Therefore, this study not only demonstrated the value of this new combination of ART/DHA as a new strategy for breast cancer therapy but also showed enhanced cytotoxicity and potential metastatic activity of lipid-based formulations against human breast cancer cells that indicate great potential for pre-clinical and clinical translation.
Lupeol and its esters : NMR, powder XRD data and in vitro evaluation of cancer cell growth.
(2018) Silva, Aline Teixeira Maciel; Magalhães, Cássia Gonçalves; Duarte, Lucienir Pains; Mussel, Wagner da Nova; Ruiz, Ana Lucia Tasca Gois; Shiozawa, Larissa; Carvalho, João Ernesto de; Trindade, Izabel Cristina; Vieira Filho, Sidney Augusto
The triterpene lupeol (1) and some of its esters are secondary metabolites produced by species of Celastraceae family, which have being associated with cytotoxic activity. We report herein the isolation of 1, the semi-synthesis of eight lupeol esters and the evaluation of their in vitro activity against nine strains of cancer cells. The reaction of carboxylic acids with 1 and DIC/DMAP was used to obtain lupeol stearate (2), lupeol palmitate (3) lupeol miristate (4), and the new esters lupeol laurate (5), lupeol caprate (6), lupeol caprilate (7), lupeol caproate (8) and lupeol 3’,4’-dimethoxybenzoate (9), with high yields. Compounds 1-9 were identified using FT-IR, 1H, 13C-NMR, CHN analysis and XRD data and were tested in vitro for proliferation of human cancer cell activity. In these assays, lupeol was inactive (GI50> 250μg/ mL) while lupeol esters 2 -4 and 7 - 9 showed a cytostatic effect. The XRD method was a suitable tool to determine the structure of lupeol and its esters in solid state. Compound 3 showed a selective growth inhibition effect on erythromyeloblastoid leukemia (K-562) cells in a concentration-dependent way. Lupeol esters 4 and 9 showed a selective cytostatic effect with low GI50 values representing promising prototypes for the development of new anticancer drugs.
Mechanisms of interaction of biodegradable polyester nanocapsules with non-phagocytic cells.
(2018) Trindade, Izabel Cristina; Lana, Gwenaelle Elza Nathalie Pound; Pereira, Douglas Gualberto Sales; Oliveira, Laser Antônio Machado de; Andrade, Margareth Spangler; Vilela, José Mário Carneiro; Postacchini, Bruna Bueno; Mosqueira, Vanessa Carla Furtado
The interaction of polymer nanocapsules (NC) prepared from four biodegradable polyesters with variable polymer hydrophobicity (PCL, PLA, PLGA and PLA-PEG) was investigated in the non-phagocytic Vero, Caco-2 and HepG2 cell lines. The NC, labeled with the highly lipophilic fluorescent indocarbocyanine dye DIL, had very similar sizes (approx. 140 nm) and negative zeta-potentials. Asymmetric flow field-flow fractionation evidenced NC colloidal stability and negligible transfer of the dye to serum proteins in the incubation medium. The cytotoxicity of the NC was evaluated via MTT assay over a large polymer concentration range (1–1000 μg/mL) and time of exposure (2, 24 and 48 h). The NC were safe in vitro up to a concentration of approx. 100 μg/mL or higher, depending on the cell line and nature of the polymer. Vero cells were more sensitive to the NC, in particular NC of the more hydrophobic polymer. The cells were exposed to endocytosis inhibitors, incubated with NC, and the cell-associated fluorescence was quantified by spectrofluorometry. HepG2 cells presented a 1.5–2-fold higher endocytic capacity than Caco-2 and Vero cells. The main mechanism of NC uptake was caveolin-mediated endocytosis in HepG2 and Vero cells, and macropinocytosis in Caco-2 cells. Polymer hydrophobicity had an effect on the level of NC associated to HepG2 cells and to a lesser extent on the endocytosis mechanisms in Vero and Caco-2 cells. The NC uptake levels and endocytosis mechanisms differed significantly between cell lines tested.
Phthalocyanine photosensitizer in polyethylene glycol-block-poly(lactide-co-benzyl glycidyl ether) nanocarriers : probing the contribution of aromatic donor-acceptor interactions in polymeric nanospheres.
(2019) Lana, Gwenaelle Elza Nathalie Pound; Garcia, Giani Martins; Trindade, Izabel Cristina; Oliveira, Patricia Capelari de; Pontífice, Thaís Godinho; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Nottelet, Benjamin; Postacchini, Bruna Bueno; Mosqueira, Vanessa Carla Furtado
For best photosensitizer activity phthalocyanine dyes used in photodynamic therapy should be molecularly dispersed. Polyethylene glycol-block-polylactide derivatives presenting benzyl side-groups were synthesized to encapsulate a highly lipophilic phthalocyanine dye (AlClPc) and evaluate the effect of π-π interactions on the nanocarrier colloidal stability and dye dispersion. Copolymers with 0, 1, 2 and 6 mol% of benzyl glycidyl ether (BGE) were obtained via polyethylene glycol initiated ring-opening copolymerization of D,L-lactide with BGE. The block copolymers formed stable, monodisperse nanospheres with low in vitro cytotoxicity. AlClPc loading increased the nanosphere size and affected their colloidal stability. The photo-physical properties of the encapsulated dye, studied in batch and after separation by field flow fractionation, demonstrated the superiority of plain PEG-PLA over BGE-containing copolymers in maintaining the dye in its monomeric (non-aggregated) form in aqueous suspension. High dye encapsulation and sustained dye release suggest that these nanocarriers are good candidates for photodynamic therapy.