Antitumor and immunomodulating activities of six Phellinus igniarius polysaccharides of different origins

The aim of the current study was to compare the antitumor efficiency of Phellinus igniarius polysaccharides (PIP) from six different origins and preliminarily investigate its potential mechanisms. PIP was extracted using the microwave extraction method. The corresponding in vivo antitumor efficacy was assessed in Kunming mice bearing H22 tumors and Gansu PIP (GPIP) was identified to have a significantly higher antitumor efficacy compared with the control group (P<0.05), while no significant difference was observed following treatment with PIP from different origins (P>0.05). The spleen index of the GPIP group significantly increased compared with the saline and CTX groups (P<0.01). The in vitro MTT assay of GPIP on HepG2 cells indicated that GPIP had no direct cytotoxicity. The serum immune cytokines of interleukin-2, interleukin-12 and interferon-γ were assessed using the ELISA method. The concentration of all three serum cytokines significantly increased compared with saline and CTX groups (P<0.01) indicating that activating the immune system may be a potential antitumor mechanism. These results demonstrated that GPIP has great potential as a natural antitumor agent with immunomodulatory activity.