Structural characterization, sulfation and antitumor activity of a polysaccharide fraction from Cyclina sinensis

In the present study, we investigated the preliminary structure, sulfation and antitumor activity of a polysaccharide fraction from Cyclina sinensis (CSPS-1). Results of structural characterization showed that the backbone chain of CSPS-1 was composed of glucose linked by α-(1 → 4) glycosidic bond, and the branch chain was attached to backbone chain by (1 → 6) glycosidic bond. CSPS-1 was sulfated by chlorosulfonic acid-pyridine method under different modification conditions according to the orthogonal test L9(34), affording nine sulfated polysaccharides (CSPS-1-S). The optimal sulfation conditions for CSPS-1 were reaction temperature of 65 °C, reaction time of 2 h and chlorosulfonic acid-pyridine ratio of 1:4. Structural analysis revealed that sulfation had occurred at position of C-6 in CSPS-1. In addition, CSPS-1-S exhibited significantly higher inhibitory activity in vitro against human gastric cancer BGC-823 cells.