Estrutura e mecanismo molecular envolvido no efeito anti-inflamatório de uma fração polissacarídica sulfatada de Gracilaria birdiae

• Ano de defesa: 2020
• Autor(a) principal: Soares, Vitória Virgínia Magalhães
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Macroalga vermelha; Agarana sulfatada; Inflamação; Estresse oxidativo; Via fator nuclear κB
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/53601

Seaweeds are sources of bioactive compounds and has attracted interest due to their cosmeceutical, nutraceutical, biotechnological and pharmacological applications. Among these compounds, we can emphasize the sulfated polysaccharides (SP), which have anticoagulant, antioxidant, antiviral properties, act on neuroprotection and as anti- inflammatory agents. The sulfated polysaccharides from alga Gracilaria birdiae has shown anti-inflammatory activity, but its mechanism has not been elucidated clearly. Thus, this study aims to characterize a sulfated polysaccharide fraction of G. birdiae (Gb- FI) and to evaluate the molecular mechanisms involved in its anti-inflammatory effect. Initially, the total sulfated polysaccharides (TSP) were extracted in the presence of the proteolytic enzyme papain, fractionated by ion exchange chromatography with DEAE- cellulose column and the fraction obtained was characterized by spectroscopic methods. To determine the anti-inflammatory effect of Gb-FI and its mechanism, were performed paw edema assays induced by various inflammatory agents. To evaluate the oxidative stress, biochemical dosages were performed, such as determination of nitrite/nitrate content, lipid peroxidation levels and reduced glutathione (GSH) production. Besides that, the interaction of Gb-FI with E-selectin was verified by molecular docking. The levels of genes expression involved in the inflammatory process (TNF-α, IL-1β, IL-6, COX-2, iNOS, HO-1, IL-10 and NF-κB) were analyzed by real time PCR. The results revealed that Gb-FI is formed mainly of repeating units β-D-galactopyranose-4-sulfate- (1→4)-3,6-anhydro-α-L-galactopyranose, with molar mass of 189.5 kDa. Pretreatment with Gb-FI, at the dose of 5 mg/Kg, inhibited the rat paw edema induced by carrageenan, dextran, histamine, serotonin, compound 48/80 and L-arginine, in 76.1%, 34%, 33.6%, 15%, 28% and 65.4%, respectively. Differently, FI-Gb was not effective in reducing bradykinin-induced edema. Molecular docking indicated that Gb-FI may interact with E- selectin, reducing the leukocyte recruitment to the inflammatory focus. In addition, biochemical parameters revealed that Gb-FI decreased the production of nitric oxide and malondialdehyde and increased the GSH levels. Finally, Gb-FI downregulated proinflammatory cytokines and mediators (TNF-α, IL-1β, IL-6, iNOS, COX-2 e NF-κB) and upregulated anti-inflammatory genes (IL-10 and HO-1), compared with carrageenan group. Thus, Gb-FI has anti-inflammatory effect and can act on multiple targets in the inflammatory response pathways.