Animal model
All animal experiments were approved by the Institutional Animal Care and Treatment Committee of Sichuan University. Female BALB/c nude mice, aged 5 weeks, were purchased from HFK Bioscience Co., Ltd (Beijing, China). The mice were housed under standard conditions. For the subcutaneous xenograft model, DLD-1 cells (1 x 107cells/mouse) were suspended in PBS and injected into flanks of mice subcutaneously. When the tumor volume reached ~50mm3, mice were randomly divided into two groups. The mice were administered with 0.1 ml vehicle (10% ricinus oil, 5% DMSO, 10% ethanol, 75% physiologic saline) or Ziyuglycoside II (50 mg/kg/d) by gavage. The tumor volumes were measured every other day and evaluated according to the following formula: tumor volume(mm3) = (length x width2)/2. 4 weeks post treatment, the mice were euthanized and tumors were harvested.