Purification and structural elucidation of chondroitin sulfate/dermatan sulfate from Atlantic bluefin tuna (<i>Thunnus thynnus</i>) skins and their anticoagulant and ACE inhibitory activities

Abstract

Chondroitin sulfate/dermatan sulfate (CS/DS) was extracted from Atlantic bluefin tuna (<i>Thunnus thynnus</i>) skin (SGAT) and was purified and characterized. SGAT was characterized by acetate cellulose electrophoresis, FTIR spectroscopy, ¹³C NMR spectroscopy and SAX-HPLC. According to the results obtained for specific chondroitinases (ABC and AC) and the SAX-HPLC separation of generated unsaturated repeating disaccharides, the polymer was found to contain a disaccharide monosulfated in positions 6 and 4 of GalNAc and disulfated disaccharides in different percentages. These results were confirmed by ¹³C NMR experiments. The average molecular mass was 24.07 kDa, as determined by PAGE analysis. SGAT was evaluated for its <i>in vitro</i> anticoagulant activity <i>via</i> activated partial thromboplastin time, thrombin time and prothrombin time tests. The polymer showed strong inhibitory activity against angiotensin I-converting enzyme (IC₅₀ = 0.25 mg mL^-1). Overall, the results suggest that this newly extracted CS/DS can be useful for pharmacological applications.