Turmeric is a yellow spice used in making curry powder. Derived from the Curcuma longa plant root, turmeric has been researched with regard its ability to improve health. Turmeric is a known in vitro antioxidant, and evidence shows that it may also act as a potent antioxidant in humans. Other evidence shown that turmeric has potent anti-inflammatory effects. This anti-inflammatory effect may explain in parts its ability to inhibit the promotion and progression of cancer.
Chemical studies on turmeric have attempted to isolate the compound responsible for its beneficial effects. In the course of this research, a compound called curcumin has been isolated and tested and found to possess many of the effects attributed to the whole herb. This indicates that curcumin could be the active ingredient. However, as with all plants it is likely that the effects come from a variety of chemicals and so curcumin may only be partly responsible.
The ability of curcumin to inhibit cancer promotion and progression in cell culture experiments may relate to its potent anti-inflammatory effects. Curcumin is a cyclooxygenase inhibitor, and in this role can block one of the enzymes capable of producing pro-inflammatory compounds. Aspirin is a well known cyclooxygenase inhibitor, originally isolated from the bark of the white willow tree. This explains the ability of aspirin to reduce the risk of certain forms of cancer.
Cell Culture Relevance
While cell culture experiments have identified probable mechanisms of action of curcumin, controversy surrounds the usefulness of such experiments in humans. Humans are not plates of isolated cells of one type grown in artificial media, but complex interactive organisms that are composed of trillions of types of cell. Therefore the usefulness of cell culture experiments will always be questioned regarding the extrapolation to whole organisms.
Whole Herb or Curcumin?
Supplements of turmeric standardised for curcumin are available. However, the epidemiological evidence showing a reduction in the incidence of cancer have involved investigating populations that consume the whole herb. Indian people do not buy and consume turmeric supplements to achieve their protection from all forms of cancer, but they cook with and eat the whole herb. This is therefore the most logical way to achieve the known anti-cancer effects of turmeric.