Objective: To investigate the mechanisms and reversal effects of Jianpi Jiedu formula on human colon carcinoma multidrug resistance (MDR) in HCT8/V cells. Method: Human colon carcinoma MDR cells were cultured conventionally. The concentration of Jianpi Jiedu formula (5%) combined with chemotherapy drugs and the reversal effect of multidrug resistance (MDR) in HCT8/V cells was evaluated by the MTT assay. The variation of intracellular concentration of vincristine(VCR) in HCT8/V cells was evaluated by the HPLC

and the effects of Jianpi Jiedu formula on 5-Fu induced apoptosis and cell cycle were evaluated by flow cytometry (FCM). Result: Jianpi Jiedu formula could increase the sensitivity of HCT8/V cells to VCR

DDP

5-Fu

THP. The IC50 value of VCR decreased from (191.08±18.18) mg·L-1 to (90.13±6.33) mg·L-1

DDP was from (290.79±28.38) mg·L-1 to (22.16±1.82) mg·L-1

5-Fu was from (23.12±1.99) mg·L-1 to (9.88±0.86) mg·L-1

and THP was from (26.40±2.92) mg·L-1 to (19.41±1.48) mg·L-1. HPLC results showed that Jianpi Jiedu formula increased the concentration of drugs in HCT8/V cells in a dose-dependent manner after treatment for 48 h. Flow cytometry assay result verified that the inhibited effects of Jianpi Jiedu formula combined with 5-Fu on the proliferation of HCT8/V cells was closely related to the arrest in G1 phase and increasing of apoptosis. Conclusion: Jianpi Jiedu formula can reverse MDR in HCT8/V cell

which possibly through inhibiting cell proliferation

inducing cell-apoptosis

ultimately affect the concentration of drugs inside the cells.