Chemical structure, anti-inflammatory and antinociceptive activities of a sulfated polysaccharide from Gracilaria intermedia algae.

The present work aimed at carrying out the isolation and biochemical characterization of a sulfated polysaccharide fraction (PLS) from the marine algae Gracilaria intermedia and investigating its anti-inflammatory and antinociceptive potential. PLS was obtained through enzymatic digestion with papain and analyzed by means of gel permeation chromatography and Nuclear Magnetic Resonance to H and C. In order to evaluate the potential of anti-inflammatory action of PLS, we performed paw edema induced by carrageenan, dextran, compound 48/80, histamine and serotonin. In addition, we also measured the concentration of myeloperoxidase, cytokines, the count of inflammatory cells and performed tests of the nociception. The PLS isolated was of high purity and free of contaminants such as proteins, and had molecular weight of 410 kDa. The same macromolecule was able to decrease the paw edema induced by all inflammatory agents (P < 0.05), myeloperoxidase (MPO) activity, neutrophil migration and IL-1β levels. It also decreased acetic acid-induced writhing (P < 0.05) and formalin-induced paw licking time (P < 0.05), but no in hot plate test. In summary, the PLS decreased the inflammatory response by reducing neutrophil migration and modulating IL-1β production and antinociceptive effects by a peripheral mechanism dependent on the down-modulation of the inflammatory mediators.