Caracterização estrutural e propriedades bioativas dos polissacarídeos sulfatados da alga marinha vermelha Gelidiella acerosa

Abstract

Red seaweeds are a natural source of several bioactive compounds, especially carbohydrates. Among these polymers, the sulfated polysaccharides are complex molecules that have aroused great interest in the biomedical field. Therefore, the study aimed to isolate the sulfated polysaccharides from the red seaweed Gelidiella acerosa (GaSP) and to verify its bioactive potential as anticoagulant, antithrombotic, antiplatelet and antioxidant agent. The GaSP have a mean molar mass of 284.8 kDa and carbohydrate content of 89.5%. In addition, the microanalysis showed levels of carbon (32%), hydrogen (5.4%), sulfur (4.5%). The chemical characterization of GaSP was performed through Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) analyzes, identifying the GaSP as a sulfated galactan of the agaran type. The anticoagulant activity was investigated by the classical tests of APTT and PT and the antithrombotic activity and hemorrhagic tendency were evaluated by the venous thrombosis model and bleeding time test, respectively. The antioxidant potential was evaluated through the following tests: total antioxidant capacity, ferrous ion chelation ability, capacity of scavenging DPPH radical and hydroxyl radical elimination activity. the GaSP were able to prolong the coagulation time in the APTT test and inhibited platelet aggregation. In addition, they had a significant dose-dependent antithrombotic effect, without hemorrhagic disturbs, of 40%, 64% and 80% at 0.1, 0.5 and 1 mg/kg, respectively. The sulfated polysaccharides presented high antioxidant activity in all tests performed with results of 41.7%, 66.6%, 70.6% and 98.2% against the radical DPPH, on the chelation of iron ions, on the elimination of the hydroxyl radical and on the total antioxidant capacity, respectively. The results suggest the sulfated polysaccharides of G. acerosa as alternative natural agents with promising antithrombotic and antioxidant activity.