Chemical characterization and antioxidant activity of sulfated polysaccharide from the red seaweed Gracilaria birdiae

• Autor(a) principal: Souza, B. W. S.
• Data de Publicação: 2012
• Outros Autores: Cerqueira, M. A., Bourbon, A. I., Pinheiro, A. C., Martins, Joana, Teixeira, J. A., Coimbra, Manuel A., Vicente, A. A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/22295
• topic: Gracilaria; Sulfated polysaccharide; Antioxidant activity; Science & Technology

Hydrocolloids from seaweeds have interesting functional properties, such as antioxidant activity and gelling ability. A polysaccharide was isolated by aqueous extraction at 90 C from the red seaweed Gracilaria birdiae (Gb), with a yield of 27.2% of the seaweed dry weight. The sulfate content of the polysaccharide was 8.4% and the main sugars present were galactose (65.4 mol%), 3,6-anhydrogalactose (25.1 mol%) and 6-O-methylgalactose (9.2 mol%). Gel permeation chromatography showed that Gb polysaccharide is a heterogeneous system, with molar mass at the main peak of 3.7 105 g mol1 and a shoulder of 2.6 106 g mol1. The sulfated polysaccharide of Gb characterized by FTIR exhibits the characteristic bands of agarocolloids (at 1375 and 770 cm1).The rheological behavior of Gb sulfated polysaccharide exhibits a gel-like behavior close to the one observed in commercial agar. The antioxidant properties of Gb sulfated polysaccharide were evaluated by measuring DPPH freeradical scavenging effect, showing that this polysaccharide has a moderate effect in inhibiting the formation of those radicals.