Banca de QUALIFICAÇÃO: THIAGO LAURENTINO ARAÚJO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : THIAGO LAURENTINO ARAÚJO
DATA : 15/05/2018
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TÍTULO:

SULFATED POLYSACCHARIDES FROM Dictyota menstrualis WITH ANTIOXIDANT, ANTIPROLIFERATIVE AND ANTICOAGULANT ACTIVITIES

PALAVRAS-CHAVES:

fucan, brown algae, antioxidant activity, anticoagulant activity, celular viability.

PÁGINAS: 85
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Fucans constitute a group of sulphated polysaccharides found in the muscilaginous matrix of brown algae which present complex structure, are very diversified and are constituted by fucose, sulfate and a varied percentage of different monosaccharides. The fraction F1.0v rich in fucanas was fractionated. The resulting fractions were characterized chemically and the one of better yield was compared with F1.0v as to its effect in antioxidant activity, anticoagulant, proliferation and cell death assays.The composition of F1,0v and F1 were 48.6 and 51.8% of total sugars, 2.3 and 3.1% of sulfate and low protein contamination, respectively. The F1 infrared analysis showed signals at 3460, 2927, 1632, 1412, 1250 and 1041, 810 and 590 cm^-1 assigned to the axial stretching of the HO group, -CH-vibration, water binding to the hydroxyl groups, vibration of CH2- , sulfate ester (S = O), symmetrical vibration of CO and vibration of C-O-S. Both F1.0v and F1 presented high inhibition of hydroxyl radicals (186% and 174%), superoxide radicals (76% and 61%) and DPPH radicals (74 and 68%). No chelation of iron and copper ions was observed. F1 presented the same effect as commercial low molecular weight heparin in the aPTT assay, at the concentration of 66.7 μg/mL, while F1.0v 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 F1,0v and F1 is directed towards the intrinsic pathway. In the MTT assay, F1.0v and F1 caused 100% inhibition on the A2058 cell line at 24h with the mass of 1000μg; high inhibition (79.6 and 83%, respectively) over A375 with the same mass; and 100μg F1.0v inhibited B16-F10 by 77%. F1.0v and F1 inhibited 786-O by 92% and 100%, respectively, under the 100μg mass at 24h. In the 786-O cell death assay, under the same mass, no fraction caused cell death. These results suggest that the F1.0v and F1 fractions present high antioxidant activity on the major radicals responsible for cell damage, making them potential antioxidants to be exploited. The high anticoagulant activity observed on the intrinsic coagulation pathway suggests that the sulfated polysaccharides of D. menstrualis may be a source of possible anticoagulant agents and high inhibition of 786-O cells in the MTT assay should be further investigated for the verification of its antiproliferative potential on the cancer cell line.

MEMBROS DA BANCA:
Externo ao Programa - 2832746 - MONIQUE GABRIELA DAS CHAGAS FAUSTINO ALVES
Externo à Instituição - IVAN RUI LOPES DE ALBUQUERQUE - SECD-10DIRED
Externo à Instituição - MARIANA SANTANA SANTOS PEREIRA DA COSTA - IFRN