Chain conformation and anti-tumor activities of phosphorylated (1→3)-β-d-glucan from Poria cocos

Abstract (1→3)-β- d -Glucan isolated from Poria cocos was phosphorylated to obtain a series of phosphorylated derivatives. Their structures, weight-average molecular weights ( M w ), and chain conformation were studied by 13 C NMR, 31 P NMR, static laser light scattering and viscometry. The experimental results revealed that the phosphorylated glucan existed as relatively extended flexible chain in 0.15 M NaCl aqueous solution, and exhibited relatively strong inhibition against S-180 tumor cell in vitro and in vivo . In vivo , the fractions with relatively high molecular weight at low dosage exhibited stronger anti-tumor activities. The results revealed that the molecular weights and molecular conformation could influence the anti-tumor activities. The molecular weight ranging from 2.6 × 10 4 to 26.8 × 10 4 and the extended chain conformation were beneficial to enhance the anti-tumor activity, as a result of the increasing of the interaction between polysaccharide and immune system.