Curcumin, the main chemical part of turmeric, has raised interest because of its activity against inflammation and cancer. These scientists were concerned that curcumin could interfere with anti-cancer drugs. This is because curcumin inhibited two steps in the pathway of these drugs. These steps are, making of reactive oxygen species (ROS) and the c-Jun NH (2)-terminal kinase (JNK) pathway. They are how many cancer drugs start programmed cell death, a process called apoptosis. In their experiments, curcumin inhibited the apoptosis of human breast cancer cells (MCF-7, MDA-MB-231, and BT-4) caused by chemotherapy by up to 70%. They used the anti-cancer drugs; camptothecin-, mechlorethamine-, and doxorubicin. This inhibition was greater when cells were treated with more and longer curcumin. But they saw this inhibition even with short, 3 hours, durations of curcumin. Even the low amount of curcumin, 1 micromole, found in Phase I clinical trials of human, inhibited this apoptosis. In these studies curcumin was an antioxidant. It blocked the activation of JNK and mitochondrial release of cytochrome c in a concentration-dependent manner. They also looked at curcumins effect in mice injected with human breast cancer cells. Curcumin in mouse diets reduced the tumor decreasing effect of the anti-cancer drug, cyclophosphamide. It also blocked the cyclophosamide caused events, activation of apoptosis and JNK. They concluded that curcumin in the diet can interfere with cancer chemotherapy by inhibiting apoptosis. They suggest that additional studies should look at whether curcumin should be avoided by breast cancer patients undergoing chemotherapy.
Dietary curcumin inhibits chemotherapy-induced apo…[Cancer Res. 2002]