Abstract: Objective: To investigate the anti-tumor activity in vivo of sesquiterpenoids from ginseng (SPG) in the S₁₈₀ tumor-bearing mice, and to clarify its mechanism.Methods: The ICR male mice were used to establish the S₁₈₀ tumor-bearing models. The model mice were randomly divided into model group, 5-fluorouracil (5-FU) group (20 mg·kg^-1, ip), low dose of SPG group (2.5 mg·kg^-1, ig),and high dose of SPG group (10.0 mg·kg^-1, ig), 8 mice in each group;another 8 mice were selected and used as blank control group. Fourteen days after administration, the blood samples were collected from the eyes of all mice, and they were sacrificed by cervical dislocation, then the tumor tissue was excised and weighed;the inhibitory rate of tumor was calculated;the serum levels of alanine aminotransferase(AST), aspartate aminotransferase(ALT), urea nitrogen(BUN), interleukin-2(IL-2), tumor necrosis factor-α(TNF-α) and vascular endothelial growth factor (VEGF) of the mice in various groups were measured;the pathological changes of the tumor tissue of the mice in various groups were observed by HE staining;the expression levels of anti-apoptotic factor Bcl-2, VEGF, p38 against mitogen-activated protein kinase (p38MAPK) and p-p38 against mitogen-activated protein kinase (p-p38MAPK) in the tumor tissue of the mice in various groups were analyzed by Western blotting method.Results: The inhibitory rates of the mice in SPG groups were increased significantly as the increase of SPG dose, and the inhibitory rate of tumor of the mice in high dose of SPG group was 76.29%. Compared with model group, the serum levels of IL-2 and TNF-α of the mice in SPG groups were significantly increased (P<0.01) and the levels of ALT, AST, BUN and VEGF were significantly decreased (P<0.05 or P<0.01). The HE staining results showed that the cells in model group were arranged neatly, a large number of nuclei were observed and the growth state was good;in low and high doses of SPG group, the number of nuclei in the tumor tissue of the mice was significantly reduced, the arrangement was loose, and a large area of necrosis occurred.The Western blotting results showed that compared with model group, the expression levels of Bcl-2 and VEGF proteins were significantly decreased (P<0.01) and the expression levels of p-p38MAPK protein in low and high doses of SPG groups were significantly increased (P<0.01).Conclusion: SPG has a good anti-tumor effect in the S₁₈₀ tumor-bearing mice, and its mechanism may be associated with the decreasing of Bcl-2 and VEGF expressions and activation of p38 MAPK protein channel.

Key words: sesquiterpenoids from ginseng, anti-tumor activity, 5-fluorouracil, S₁₈₀ tumor-bearing mice