Banca de DEFESA: THIAGO LAURENTINO ARAÚJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : THIAGO LAURENTINO ARAÚJO
DATA : 29/06/2018
HORA: 09:00
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TÍTULO:

FUCANS EXTRACTED FROM BROWN ALGA Dictyota menstrualis WITH ANTIOXIDANT, ANTIPROLIFERATIVE AND ANTICOAGULANT ACTIVITIES

PALAVRAS-CHAVES:

sulfated polysacharide, brown algae, celular viability, blood coagulation

PÁGINAS: 96
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Fucans consist in a group of sulphated polysaccharides found in the mucilaginous matrix of brown algae constituted by sulfated fucose and a varied percentage of other monosaccharides. Faced with the great demand for new medicines, fucanas are outstanding due to their pharmacological potential, whose repertoire of properties includes anticoagulant, antioxidant, anti-inflammatory, antiproliferative, antinociceptive, hepato and neuroprotective activities. The fraction FDM1,0 rich in fucanas was fractionated. Fucan FDM1,0 of the algae Dictyota menstrualis obtained in a previous study was chosen because it had the best yield to be purified. FDM1.0 was fractionated by molecular mass resulting in 7 subfractions (F1 to F7) which were chemically characterized. The highest dry weight obtained was F1 with yield of 61.34%. FDM1.0 and F1 were compared for their effect in antioxidant activity, anticoagulant, antiproliferation and cell death assays. FDM1.0 and F1 presented 48.6 and 51.8% of total sugars, 2.3 and 6.1% of sulfate and low protein contamination, respectively. Infrared analysis of FDM1.0 and F1 showed characteristic polysaccharide signals. Both FDM1.0 and F1 presented high inhibition superoxide radicals (76 and 61%) and DPPH radicals (74 and 68%). No chelation activity was observed for iron and copper ions. F1 presented the same effect as low molecular weight commercial heparin in the aPTT assay, at the concentration of 66.7 μg / mL, while FDM1.0 at the concentration of 83.3 μg / mL. In the PT assay, none of the fractions presented anticoagulant activity, indicating that the mechanism of action of FDM1,0 and F1 is directed towards the intrinsic pathway of coagulation. In the MTT assay (3- [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide), FDM1.0 and F1 caused 100% inhibition on A2058 (benign human melanoma) cells treated by 24h with 1000μg of the samples; high inhibition (79.6 and 83%, respectively) on A375 (human malignant melanoma) of the same mass; and 100μg of FDM1.0 inhibited B16-F10 (murine malignant melanoma) by 77%. FDM1.0 and F1 inhibited 92 and 100%, respectively, 786-O (human renal cell adenocarcinoma) cells under the 100 μg mass, when treated for 24 h. In the 786-O cell death assay, under the same mass, no fraction caused cell death. These results suggest that the FDM1.0 and F1 fractions present high antioxidant activity on the main radicals responsible for cellular damage, making them the potential antioxidants to be explored. The high anticoagulant activity observed on the intrinsic coagulation pathway suggests that sulphated polysaccharides of D. menstrualis may be a source of possible anticoagulant agents and the high inhibition of 786-O cells in the MTT assay should be further investigated to verify their potential antiproliferative activity on the cancer cell line.

MEMBROS DA BANCA:
Externo à Instituição - LEONARDO THIAGO DUARTE BARRETO NOBRE - UFRN
Presidente - 3315429 - LUCIANA GUIMARAES ALVES FILGUEIRA
Externo à Instituição - MARILIA DA SILVA NASCIMENTO SANTOS - IFRN