Banca de QUALIFICAÇÃO: ALMINO AFONSO DE OLIVEIRA PAIVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ALMINO AFONSO DE OLIVEIRA PAIVA
DATA : 13/06/2016
HORA: 15:30
LOCAL: Sala de reuniões do CB
TÍTULO:

Prospecting of bioactive polysaccharides variegata Lobophora seaweed and structural elucidation of one of his laminarinas

PALAVRAS-CHAVES:

β-glucan, chelation of metals, immunomodulatory, antiproliferative.

PÁGINAS: 117
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Seaweeds are important sources of neutral and negative polysaccharides with important industrial and pharmacological potential. The brown macroalgae Lobophora variegata is known for presenting sulfated polysaccharides (heterofucanas) and neutral (laminarinas). In this work shows is getting 6 polysaccharide fractions (F0.3, F0.5, F0.8, F1, F1.5 and F2). From the data of physicochemical characterization of fractions, we chose to F1 to purify its polysaccharide components. Liquid chromatography analysis carried molecular exclusion observation shows that F1 polysaccharide components of low (~ 5 kDa) to high (> 100 kDa) molecular. These components were separated according to their molecular weight, using ultrafiltration devices. Thus, there was obtained subfractions with an average polysaccharide size of 5, 20, 40, 75 and above 100 kDa, named F1-5, F1-20, F1-40. F1-75 and F1> 100 kDa, respectively. These subfractions were analyzed physico-chemically by agarose gel electrophoresis, high performance liquid chromatography, as by analysis of their antioxidant properties, immunomodulatory and cytotoxic / antiproliferative. As a result, we detected a total sugar content above 55% in all subfractions, since proteins and phenolic compounds were observed. The F1-5 fractions, F1-20 and F1-40 have only glucose (glucans), as F1-75 and F1> 100 have glucose, galactose and fucose (heterofucanas). All subfractions showed chelating activity of metals, but only F1-75 and F1> 100 showed scavenging activity of radicals. The production / release of NO by RAW cells was increased only in the presence F1-5 (10 uM), F1-75 (10 uM) (p <0.001) and, especially, F1> 100 (10 uM) whose presence increased about 12 times the amount of NO (p <0.001). However, when these cells were activated with LPS only F1-20 and F1> 100 (10 uM) (p <0.001) yielded production / release of NO. The other fractions did not interfere in the LPS action. Only F1-5 and F1> 100 stimulated the production / release of cytokines. Only F1> 100 (10 uM) was cytotoxic to line 3T3 (fibroblast) (p <0.01). None of subfractions showed cytotoxicity to cell line RAW 264.7 (macrophages) or are tumor cell line Hep-G2 (hepatocellular carcinoma). Now the cell lineage 786-0 (renal cell carcinoma) only glucan F1-40 showed no cytotoxic activity (p> 0.05). The highest cytotoxicity values were obtained with the subfraction F1-20, in the case against B16F10 cells (melanoma). Flow cytometry data indicate that this subfraction promotes stopping of cells in the G1 phase of the cell cycle (p <0.01) Nuclear magnetic resonance .Análises led to the proposal that F1-20 is a β-glucan (Laminarin one) formed by β- (1 to 3) glucosides with branches, comprising a glucose residue at position 6. The ratio is nine 1.3 glucose residues connected to each branching point. The data point F1-20, being an antioxidant, immunomodulating and cytotoxic as a compound pluripotent whose potential should be further investigated.

MEMBROS DA BANCA:
Externo à Instituição - DIEGO DE ARAUJO SABRY - UNIFESP
Externo ao Programa - 1046922 - LEONARDO CAPISTRANO FERREIRA
Presidente - 3315429 - LUCIANA GUIMARAES ALVES FILGUEIRA