Depolymerization of sulfated polysaccharides under hydrothermal conditions

Fucoidan and chondroitin sulfate, which are well known sulfated polysaccharides, were depolymerized under hydrothermal conditions (120-180 degrees C, 5-60 min) as a method for the preparation of sulfated polysaccharides with controlled molecular weights. Fucoidan was easily depolymerized, and the change of the molecular weight values depended on the reaction temperature and time. The degree of sulfation and IR spectra of the depolymerized fucoidan did not change compared with those of untreated fucoidan at reaction temperatures below 140 degrees C. However, fucoidan was partially degraded during depolymerization above 160 degrees C. Nearly the same depolymerization was observed for chondroitin sulfate. These results indicate that hydrothermal treatment is applicable for the depolymerization of sulfated polysaccharides, and that low molecular weight products without desulfation and deformation of the initial glycan structures can be obtained under mild hydrothermal conditions. (C) 2013 Elsevier Ltd. All rights reserved.