Immunostimulatory and anti-tumor activity of a water-soluble polysaccharide from Phellinus baumii mycelia

摘要

A 17-kDa water-soluble polysaccharide (PB) was isolated and purified from Phellinus baumii using the DEAE-Sephadex A-50 and LPLC-Sephadex G-75 methods. Exposure of RAW264.7 macrophages to PB resulted in a significant increase of the cellular proliferation rate, nitric oxide production and expression levels of the IL-1 beta, IL-18, IL-6, IL-12p35 and IL-12p40 genes. An MTT assay indicated that PB markedly suppressed the proliferation of HepG(2) human liver cancer cells in a dose-dependent manner. Cell cycle analysis demonstrated that PB caused cell cycle arrest at the S phase, and 400 mu g/ml of PB induced apoptotic cell death in HepG(2) cells after 48 h. The results suggested that PB inhibited the proliferation of HepG(2) cells by inducing cell cycle arrest at S phase, leading to apoptosis. In summary, our data indicate that the PB exerts immunoregulatory and anti-tumor activities in vitro.