Purification, structural characterization, and anticoagulant activity of chondroitin sulfate/dermatan sulfate from cobra (Naja naja atra).

Snakes are widely farmed in China, Southeast Asia, and India, with extensive applications in food and medicine; however, glycosaminoglycans (GAGs) derived from these sources remain largely understudied. In this study, GAGs were extracted and purified from the bone and carcass of the cobra (Naja naja atra) to investigate their structural characteristics and bioactivities. Structural analysis, including 1H NMR spectroscopy and disaccharide composition assays, identified the purified fractions (CBF2 and CCF2) as chondroitin sulfate/dermatan sulfate (CS/DS). These fractions exhibited structural heterogeneity, containing 35.9% and 28.8% iduronic acid, respectively, with disaccharide profiles dominated by A-type units (>80%) and high 4S/6S ratios (10.31 and 18.27, respectively). In vitro assays demonstrated that CBF2 and CCF2 possessed anticoagulant activity, prolonging activated partial thromboplastin time (aPTT) and thrombin time (TT) compared to conventional CS. These findings highlight the critical role of uronic acid epimerization in modulating the biological functions of GAGs.