Anti-tumor activity of an enzymatically synthesized alpha-1,6 branched alpha-1,4-glucan, glycogen

Oral administration of an enzymatically synthesized alpha-1,4:1,6-glycogen (ESG) at a dose of 50 mug/ml significantly prolonged the survival time of Meth A tumor-bearing mice. ESG also significantly stimulated macrophage-like cells (J774.1), leading to augmented production of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha). The weight-average degree of polymerization (DPw) and the ratio of branch linkage (BL) of ESG were 149,000 and 8.1% respectively. beta-Amylase-treated ESG, however, lost J774.1-activating activity although inhibited subcutaneous growth of Meth A tumor cells admixed with it. Its DPw and BL changed to 126,000 and 20% respectively. Partially degraded amylopectin [(AP), DPw: 110,000, BL; 5.1] was also effective at stimulating J774.1, but its activity was lower than that of ESG. Other alpha-glucans [cycloamylose (CA), enzymatically synthesized amylose (ESA), highly branched cyclic dextrin (HBCD), and beta-amylase-treated HBCD], of which DPw was lower than that of ESG, showed no J774.1-activating activity and weaker anti-tumor activity.