Cytotoxicity enhancement in MDA-MB-231 cells by the combination treatment of tetrahydropalmatine and berberine derived from Corydalis yanhusuo W. T. Wang

Aim: Our previous works have demonstrated that Chinese herb medicine yanhusuo (Corydalis yanhusuo W. T. Wang) has strong anticancer proliferation effect in MDA-MB-231 cells. The goal of this study was to find out the synergic cytotoxicity effect of three natural compounds, Tetrahydropalmatine (THP), Berberine (Ber) and Dehydrocorydaline (DHC), isolated from Corydalis yanhusuo W. T. Wang. Methods: The IC50 of THP, Ber and DHC in single use, as well as in combination use at fixed ratios and doses was measured by MTT assay. Isobologram, combination index (CI) and modified coefficient of drug interaction (CDI) methods were used for evaluation the combination effects of THP, Ber and DHC in different ratio and concentration. Results: the results indicated that the combination of THP and Ber shown the strongest anti-cancer cell proliferation effect at the ratio of 2: 3 (Ber: THP, the average CDI value was 0.5795). DHC and THP has additive cytotoxicity in MDA-MB-231 cells. But there wasn’t any synergistic effect between Ber and DHC, and it even exhibited antagonistic effect when the percentage of DHC was more than 50%. Conclusion: Our findings suggested that the combination of THP and Ber might be beneficial for anti-proliferation of MDA-MB-231 breast cancer cells through a significant synergy effect.