Caracterização físico-química e atividade da Curcuma longa L. em células endoteliais sob estresse oxidativo

• Autor(a) principal: Teles, Juliana Carvalho de Almeida Borges
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10424
• topic: Ácido gálico; Curcumina; DPPH; Estresse oxidativo; HUVEC; Gallic acid; Curcumin; Oxidative stress; CIENCIAS AGRARIAS::MEDICINA VETERINARIA

Ischemic tissue injury is quite harmful, however, reperfusion causes an exacerbated level of reactive oxygen species (ROS), which directly interfere in the cell signaling cascade, with cell deleterious effects such as lipid peroxidation, protein oxidation and DNA damage. Researches had shown the beneficial effects of antioxidants present in vegetables and among them is curcumin, an antioxidant pigment found in Curcuma longa L. rhizomes, known as turmeric or saffron. This plant has demonstrated pharmacological activities, which have been reported since antiquity, as antioxidant, anti-inflammatory, antibacterial, antifungal, antitumor, antiparasitic, antiviral, healing, hypoglycemic, neuroprotective and immunomodulatory. Therefore, the aim of this research was to evaluate the possible antioxidant action of curcumin on human umbilical vein endothelial cells (HUVEC), in culture, submitted and not submitted to oxidative stress (EO). This study was divided into three phases. In the first time, the action of standard curcumin (Sigma Aldrich, Reference C1386) was evaluated at different concentrations (0 μmol, 20 μmol, 50 μmol, 100 μmol and 1000 μmol) and for three different times of continuous exposure (24 h, 48 h h and 72 h). The EO assay was induced through cellular exposure to 1% hydrogen peroxide and through the MTT (methyl-thiazolyl-tetrazolium) reduction assay, cell viability and cytotoxicity could be assessed. In the second phase, we determinated the presence and content of antioxidant compounds in the ethanol extract of Curcuma longa L. (EEC) from Mara Rosa-GO. EEC samples were subjected to Folin-Ciocalteau tests, capture of the DPPH radical (2,2-diphenyl-1-picryl-hydrazil) and the HPLC-Fluorescence method. In the third phase of this research, the effect of EEC in HUVEC cultures was evaluated under the same experimental conditions as the first phase, in addition with the possible signaling pathways of both survival and cell death. The results showed that the cells treated with 20 μmol of standard curcumin and at 24 h and 48 h showed better cell viability and, consequently, less cytotoxicity. The occurrence of oxidative stress was validated by the decrease in cell viability within the three times variables used, but an antioxidative protection was found at 50 μmol of curcumin. In EEC, we identified gallic acid, curcumin (16.7%) and the amount of 18.1 μg / mL of extract, to reduce the DPPH radical by 50%. Results from the third phase indicated that the EEC possibly alleviated cell damage by oxidative stress at the dosage of 100 μg / ml, by decreasing the immunoexpression of caspase3 and by increasing the signaling of the SIRT1 survival route. It was concluded that both pure curcumin and EEC can improve the cell viability of HUVEC under oxidative stress.