Partial characterization, antioxidant and antitumor activities of three sulfated polysaccharides purified from Bullacta exarata

Three sulfated polysaccharides from Bullacta exarata were isolated, purified, and named BEP1, BEP2 and BEP3, respectively. The antitumor and antioxidant activities, in vitro, of three polysaccharides were investigated, including inhibition of cells proliferation, hydroxyl radical scavenging effect, superoxide radical scavenging capacity and reducing power assay. The results suggested that three polysaccharides possessed antioxidant activities in a dose-dependent manner, and BEP3 exhibited stronger antioxidant activities than BEP1 and BEP2. Furthermore, BEP3 showed significant inhibitory effects on growth of Bcap37 breast cancer cells, SW1990 pancreatic cancer cells and HeLa cervical cancer cells, and the IC50 were 135.3, 147.5 and 172.6 μg/ml, respectively. The highest inhibition rates of BEP1 and BEP2 were approximately 10% against three cancer cells. The data obtained in vitro models indicates that polysaccharides from B. exarata could be explored as novel and potential natural antioxidants and cancer prevention agents for use in functional foods.