摘要In this study,the antitumor properties and the possible molecular mechanisms of Cyclocarya paliurus polysaccharide(CP)and its phosphorylated derivative(P-CP)on CT-26 mouse colon carcinoma cells were investigated.Results found that CP had high inhibition ratio against CT-26 cells.The flow cytometry results found that CP treatment could cause the intracellular acidification,arrest the cell cycle in the S phase and increase reactive oxygen species generation.Additionally,CP treatment triggered mitochondrial membrane potential depolarization and Ca2+overloading,and broke down the balance of antioxidant system,Na+/K+-ATPase and Ca2+-ATPase.Further analysis found CP induced cell apoptosis through improving the activities of caspase-3 and caspase-9,and increasing the level of cytochrome C.Furthermore,the comparative study of antitumor effect on CT-26 cells displayed that the phosphorylation enhanced antitumor activities of polysaccharides.These results suggest CP is a potential natural therapeutic agent for colon cancer and phosphorylation represents an effective method of enhancing the antitumor activity of CP.