ABSTRACT
Seaweeds are sources of biomolecules with biological activities and pharmacological potential - for example, lectins, a group of proteins that can bind reversibly to carbohydrates or compounds containing them. The aim of this study was to elucidate the structural properties of a lectin extracted from the red seaweed Bryothamnion triquetrum (BtL) and to investigate its anti-inflammatory activity in mice. The lectin was purified by precipitation with ammonium sulfate and ion-exchange chromatography. Its secondary structure and tryptophan (Trp) microenvironment were analyzed by circular dichroism spectroscopy and steady-state fluorescence spectroscopy, respectively. The anti-inflammatory effect was evaluated by means of paw edema induced by carrageenan or dextran, myeloperoxidase activity in paw tissue, and by measurement of leukocyte and neutrophil migration and cytokine quantification in a peritonitis model. The secondary structure of BtL is mostly composed of ß-strands and unordered conformation, and it is quite resistant to extremes of pH and temperature, preserving the exposure of Trp residues under these conditions. In an assessment of biological activities, groups of mice were subjected to pretreatment with BtL before the inflammatory stimulus. BtL had anti-inflammatory effects in the models tested, and hence may be considered a molecule with potential to be used in the pharmaceutical industry.
Subject(s)
Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Lectins/chemistry , Lectins/pharmacology , Rhodophyta/chemistry , Seaweed/chemistry , Animals , Anti-Inflammatory Agents/therapeutic use , Carrageenan , Cell Movement/drug effects , Dextrans , Edema/drug therapy , Edema/pathology , Female , Hemagglutination/drug effects , Hydrogen-Ion Concentration , Interleukin-1beta/biosynthesis , Lectins/isolation & purification , Lectins/therapeutic use , Mice , Peritonitis/drug therapy , Peritonitis/pathology , Peroxidase/antagonists & inhibitors , Peroxidase/metabolism , Protein Structure, Secondary , Rabbits , Spectrometry, Fluorescence , Temperature , Tumor Necrosis Factor-alpha/biosynthesisABSTRACT
OBJECTIVES: The aim of this study was to evaluate the anti-inflammatory effect of a sulphated polysaccharide fraction (PLS) extracted from the alga Hypnea musciformis and investigate the possible involvement of the nitric oxide (NO) pathway in this effect. METHODS: The anti-inflammatory activity of PLS was evaluated using inflammatory agents (carrageenan and dextran) to induce paw oedema and peritonitis in Swiss mice. Samples of paw tissue and peritoneal fluid were removed to determine myeloperoxidase (MPO) activity, NO3 /NO2 levels, and interleukin-1ß (IL-1ß) level. The involvement of NO in the modulation of neutrophil migration in carrageenan-induced paw oedema or peritonitis was also investigated. KEY FINDINGS: Compared with vehicle-treated mice, mice pretreated with PLS (10 mg/kg) inhibited carrageenan-induced and dextran-induced oedema; it also inhibited total and differential peritoneal leucocyte counts in a model of peritonitis. These PLS effects were reversed by l-arginine treatment and recovered with the administration of a NO synthase blocker (aminoguanidine). Furthermore, PLS reduced the MPO activity, decreased IL-1ß levels, and increased NO3 /NO2 levels in the peritoneal cavity. CONCLUSIONS: PLS reduced the inflammatory response by modulating neutrophil migration, which appeared to be dependent on the NO pathway.
