Synergistic inhibitory effects of curcumin and 5-fluorouracil on the growth of the human colon cancer cell line HT-29

Chemotherapy. 2006;52(1):23-8. doi: 10.1159/000090238. Epub 2005 Dec 9.


The synergistic effect of combination treatment with COX-2 inhibitors and chemotherapy may be another promising therapy regimen in the future treatment of colorectal cancer. Curcumin, a major yellow pigment in turmeric which is used widely all over the world, inhibits the growth of human colon cancer cell line HT-29 significantly and specifically inhibits the expression of COX-2 protein. However, the worldwide exposure of populations to curcumin raised the question of whether this agent would enhance or inhibit the effects of chemotherapy. In this report, we evaluated the growth-inhibitory effect of curcumin and a traditional chemotherapy agent, 5-FU, against the proliferation of a human colon cancer cell line (HT-29). The combination effect was quantitatively determined using the method of median-effect principle and the combination index. The inhibition of COX-2 expression after treatment with the curcumin-5-FU combination was also evaluated by Western blot analysis. The IC(50) value in the HT-29 cells for curcumin was 15.9 +/- 1.96 microM and for 5-FU it was 17.3 +/- 1.85 microM. When curcumin and 5-FU were used concurrently, synergistic inhibition of growth was quantitatively demonstrated. The level of COX-2 protein expression was reduced almost 6-fold after the combination treatment. Our results demonstrate synergism between curcumin and 5-FU at higher doses against the human colon cancer cell line HT-29. This synergism was associated with the decreased expression of COX-2 protein.

MeSH terms

  • Cell Proliferation / drug effects
  • Colonic Neoplasms / drug therapy
  • Colonic Neoplasms / enzymology
  • Colonic Neoplasms / pathology*
  • Curcumin / pharmacology*
  • Cyclooxygenase 2 / metabolism
  • Cyclooxygenase 2 Inhibitors / pharmacology
  • Drug Synergism
  • Fluorouracil / pharmacology*
  • Gene Expression Regulation, Neoplastic / drug effects
  • HT29 Cells
  • Humans


  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase 2
  • Curcumin
  • Fluorouracil