Objective To prepare low molecular weight Eucheuma striatum sulfated polysaccharides. Methods Eucheuma striatum sulfated polysaccharides were degraded with hydrogen peroxide under the ultrasonic wave. Molecular weight and the content of sulfate radical, 3,6-anhydro-galactose of all sulfated polysaccharides were determined. Results The polysaccharides with molecular weight from 5000 to 40000 were prepared and the content of sulfate radical was above 18.5%. Conclusion This method is fit for preparing low molecular weight and good water-solubility polysaccharides. The post-treatment is simple and the method keeps the sulfated radical perfectly.

ObjectiveTo investigate the inhibitory effect of polysaccharides from Sargassum fusiforme on the HepG 2 cells. Methods Six kinds of polysaccharides were prepared by hot water extracting, ethanol and CaCl 2 precipitating and acid hydrolyzing. Inhibition rate of these polysaccharides on the HepG 2 cells were determined by MTT bioassay. Results Inhibition rate of two kinds of polysaccharides increased at lower concentration. Inhibition ratie of other polysaccharides increased with the increment of concentration. At the dose less than 2000mg?L -1,inhibition rate was not more than 40%. Conclusion All polysaccharide specimens obtained from Sargassum fusiforme have some inhibitory effects on human liver cancer cells HepG 2.

5 000 mg/L). ② All extracts except algin (ALG) had an obviously HSV-1 inhibitory effect. Antiviral activities of them were increasingly strengthened with their purities. Antiviral activities of extracts from flucoidan 1, F 1, F 2 and F 4 were better than acyclovir (ACV). ③ Antiviral activities of all extracts on CVB 3 were better than ribavirin injection. F 1, F 2 and F 4 had remarkable anti-CVB 3 effects. ④ The experiment showed that Sargassum fusiforme polysaccharides not only kill the above viruses directly but also restrain them via getting into cells or absorbing on cells.