Objective: To explore the mechanism of the total alkaloids of Gelsmium elegans (TAG) on the apoptosis of the human colonic carcinoma HT-29 cells. Method: The HT-29 cells were treated with TAG for 24 h and the cell proliferation was assessed by 3-(4

5-dimethylthiazol-zy1)-2

5-diphenyltetrazolium bromide (MTT) assay; 4

6-diamidino-2-phenylindole (DAPI) staining experiment and the flow cytometry (Annexin V-FITC/PI) experiment were used to observe the apoptosis of HT-29 cells. Reverse transcriptase polymerase chain reaction (RT-PCR) test was used to analyze the mRNA expression of B cell lymphoma-2 (Bcl-2) associated X protein (Bax) and Bcl-2 of HT-29 cells after 24 hours' treatment of the TAG. Caspase-3 expression of HT-29 cells was detected by UV Spectrophotometry. Result: In the study

it was demonstrated that the TAG had the inhibition against the proliferation of HT-29 cells. The average inhibitory effect (54.17%) was observed after the HT-29 cells were treated with 200 mg·L-1 of TAG for 24 h. The apoptotic effect of the TAG on HT-29 cells was also confirmed by the DAPI staining experiment and the flow cytometry (Annexin V-FITC/PI) experiment. RT-PCR assay showed that expression of Bcl-2 mRNA was lower in the TAG-treated group than that in control group(P<0.05)

but the expression of Bax mRNA was not changed obviously. The mRNA expression level of Bax/Bcl-2 in TAG-treated group was higher than that in control group (P<0.05). Caspases-3 expression was increased with the increase of TAG concentration in UV spectrophotometry (P<0.05). Conclusion: The TAG inhibited the proliferation of HT-29 cells and induced the apoptosis of HT-29 cells

and the mechanism may be associated with activating the Bax/Bcl-2 pathway.