Objective: To observe the effect of Astragali Radix polysaccharides on the proliferation of colon cancer cell line SW620

and to explore its anti-tumor mechanism. Method: SW620 cells were cultured with different concentrations of Astragali Radix polysaccharides (0.1

0.2

0.4

0.6

0.8

1.0 g ·L-1) in vitro for 48 h

and then treated with thiazole blue colorimetry (MTT) to detect the contents of Astragali Radix polysaccharides on the proliferation of human colon cancer cells SW620. Propidium iodide (PI) was used to detect the tumor cell cycle after treatment

and Annexin V/PI double staining was used to detect the apoptotic rate of tumor cells

while SW620 cells were cultured with Astragali Radix polysaccharides (1.0 g ·L-1) for 48 h in vitro. The protein expressions of Caspase-3

Caspase-9

cytochrome C

Bax and Bcl-2 were detected by Western blot

while SW620 cells were cultured with Astragali Radix polysaccharides (0.25

0.5

1.0 g ·L-1) for 48 h in vitro. Result: The growth of SW620 cells was significantly inhibited by APS in a dose-dependent manner (P<0.05

P<0.01). Compared with control group

the ratio of G2/M phase in treatment group of Astragali Radix polysaccharide 1.0 g ·L-1 was increased significantly (P<0.05

P<0.01). The early apoptosis rates

the late apoptosis rates and the total apoptosis rates were significantly higher than those in control group (P<0.05

P<0.01). Bax/Bcl-2 radio was significantly increased

and the expression of Caspase-9 was significantly decreased (P<0.05

P<0.01). The expressions of activated Caspase-3

activated Caspase-9 and cytochrome C were significantly increased (P<0.05

P<0.01). Conclusion: Astragali Radix polysaccharide could inhibit the proliferation of human colon cancer SW620 cells and induce the apoptosis of SW620 cells through mitochondrial pathway.