Effect of molecular mass on antitumor activity of heteropolysaccharide from Poria cocos.

A water-soluble heteropolysaccharide ac-PCM0 from Poria cocos was successfully fractionated using a preparative size exclusion chromatography (SEC) column, and their weight-average molecular mass (M(w)) was characterized by analytical SEC combined with laser light scattering (SEC-LLS). The results indicate that the fractions having relatively high M(w) exhibited higher inhibition ratio in vivo antitumor activity than those having M(w) below 3.29 x 10(4). However, the relatively low molecular mass was beneficial to the in vitro antitumor activity. Moreover, ac-PCM0 has a significantly higher enhancement ratio of the body weight than 5-fluorouracil, and its 50% lethal dose is above 1250 mg/kg, indicating a nontoxic nature.