Abstract: Objective: To explore the monosaccharide composition of polysaccharides extracted from Branchiostoma belcheri (PBBs), and the effect of PBBs on lymphocyte proliferation and antioxidant activity in S180-bearing mice. Methods: Polysaccharides were isolated from Branchistoma belcheri by enzymatic hydrolysis and alcohol precipitation. The monosaccharides obtained by alcoholysis with HCl-CH3OH from PBBs were determined by gas chromatography with internal standard method. S180-bearing mouse models were established and the model mice were randomly divided into six groups including model group, normal group, PBBs groups (25, 50, 100 mg/(kg·d)) and cyclophosphamide group. The tumor inhibition rate of S180-bearing mice was determined. The effect of PBBs on spleen lymphocyte proliferation was evaluated by MTT assay. The contents of SOD, MDA and GSH-Px in mouse plasma were determined using test kits. Results: The purity of PBBs was determined to be 89.3%. The neutral monosaccharides included rhamnose, xylose, fucose, mannose, glucose and galactose. PBBs administration at daily dosages of 25, 50, 100 mg/kg for 2 consecutive weeks could inhibit the growth of S180 sarcoma with inhibitory rates of 39.1%, 47.5% and 53.4%, respectively. Meanwhile, PBBs revealed an obvious reduction in MDA content and a significant increase in plasma SOD and GSH-Px activities. Conclusion: Branchiostoma belcheri is rich in PBBs that function to inhibit the growth of S180 sarcoma through enhancing spleen lymphocyte proliferation and antioxidant activity in S180-bearing mice.

Key words: polysaccharide from Branchiostoma belcheri, tumor inhibition rate, lymphocyte proliferation, antioxidant activity