Purificação, caracterização físico-química e atividade anticoagulante de glicosaminoglicanos isolados da pele de tilápia do nilo (oreochromis niloticus)

Abstract

Glycosaminoglycans (GAGs) comprise the extracellular matrix of animal tissues, and residues from processing fish commercially harvested may offer new anticoagulant agents to substitute the heparin (HEP) in medical sciences. The aim of this study was to purify, characterize physico-chemically and evaluate the anticoagulant activity of GAGs isolated from the skin of Nile tilapia, Oreochromis niloticus. The GAGs were extracted with papain in 100 mM sodium acetate buffer (pH 5.0) containing cystein and EDTA (5 mM), followed by ion-exchange chromatography on a DEAE-cellulose column using a NaCl gradient. The obtained fractions were lyophilizated and submitted to 0.5% agarose gel electrophoresis. The anticoagulant activity was assessed by the activated partial thromboplastin time (APTT) using normal human plasma and HEP standard (193 IU mg-1). The chromatographic profile separated into two different GAGs fractions (F I and F II) eluted at 0.50 and 0.75 M of NaCl, respectively, revealing fractions pattern distinct in the charge densities, but both showing GAGs with mobilities similar to standard dermatan sulfate (DS), suggesting the preliminary identification of this GAG. The GAGs modified the APTT, whose activities were, respectively, 4.72 (F I) and 23.80 (F II) IU mg-1, and expressed themselves dose-dependent. Therefore, the anticoagulant DS from O. niloticus suggests an interesting source for posterior studies of antithrombotic activity.