Abstract: Hydrogen peroxide and activated carbon were separately used for decolorization of Thesium chinense Turcz polysaccharides. The physical characteristics of the two decolorized samples were analyzed by X-ray diffractometry (XRD), thermogravimetry, laser particle size analyzer and rheometer, and their inhibitory activities against the proliferation of liver cancer cells were compared, as well as their effects on the gelation temperature of κ-carrageenan. The results showed that the crystalline structure of the activated carbon-treated sample was more obvious in the XRD pattern. Its apparent viscosity was higher than that of the hydrogen peroxide-treated sample at the same concentration. The thermogravimetric curve showed that the thermal decomposition degree of the hydrogen peroxide-treated sample was higher than that of the activated carbon-treated sample (mass loss percentage of 59.33% and 53.21%, respectively). At concentrations of 6–10 mg/mL, the activated carbon-treated sample showed inhibitory activity against the proliferation of HepG2 cells, while the hydrogen peroxide-treated samples did not have any inhibitory effect in the concentration range of 1–10 mg/mL. Furthermore, the increase in temperature hysteresis of blends of the activated carbon-treated-treated polysaccharides with κ-carrageenan was greater than that in blends of the HTP-treated polysaccharides with κ-carrageenan. Therefore, different decolorization methods can affect the structure and application characteristics of Thesium chinense Turcz. polysaccharides.

Key words: Thesium chinense Turcz. polysaccharides; decolorization; structural characteristics; carrageenan; HepG2