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.

Objective The antiviral effects of polysaccharides from Eucheuma gelatinae and Eucheuma striatum on herpes simplex virus type 1(HSV-1) and coxsackie virus(CVB3) in vitro were assayed and their antiviral mechanism was elucidated.Methods The antiviral effects of samples were evaluated with cell cytotoxicity by MTT and cytopathic effect(CPE) methods.Antiviral mechanism of two extracts was investigated by four different ways.Results and Conclusion Polysaccharides from Eucheuma gelatinae and Eucheuma striatum had an obviously HSV-1 and CVB3 inhibitory effect.Antiviral activities of two extracts(ESPA and ESPA2) were better than acyclovir(ACV).Antiviral activities of all extracts were better than ribavirin injection.Polysaccharides from Eucheuma striatum had remarkable anti-CVB3 effects.The experiment also showed that Eucheuma polysaccharides not only kill the above viruses directly but also restrain them via getting into cells or absorbing on cells.

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.

Objective To extract the sulfated polysaccharides from Grateloupia turuturu Yamada and to studyits physico-chemical properties and antiviral activities.Methods The sulfated polysaccharides were extracted from Grateloupia turuturu Yamada by hot water extraction and alcohol precipitation.Two pure polysaccharides were obtained by DEAE-52 cellulose column chromatography.The physico-chemical properties including the composition of the glycoconjugate and the content of the sulfate were analyzed.The antiviral effects of the samples on HSV-1,Cox_(3) and their cytotoxicity to Vero,Hela cell were studied by cytopathic effect(CPE) reduction assay and MTT colorimetric assay.Results The results showed that the glycoconjugate was composed of Gal and slight Glc,Xyl etc.The content of the sulfate group was more than 15%.And the polysaccharides showed good antiviral activities,especially the pure polysaccharides.Their 50% inhibited concentrations(IC_(50))on HSV-1 were(7.81) and 3.91?g?mL~(-1),selectivity index(SI)values were larger than 128 and 256,respectively.Conclusion The sulfated polysaccharides from Grateloupia turuturu Yamada have good antiviral effects on HSV-1 and Cox_(3).

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.