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

(1 -> 3)-beta-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 C-13 NMR, P-31 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 antitumor activities. The molecular weight ranging from 2.6 x 10(4) to 26.8 x 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. (c) 2009 Published by Elsevier Ltd.