Turmeric (Curcuma longa, also known as tumeric or curcumin) is a spice commonly used in curries and other south Asian cooking. It is a significant ingredient in most commercial curry powders. Turmeric is also used to give a yellow color to some prepared mustards, canned chicken broth, and other foods, and is also used as a fabric dye.
Turmeric is a member of the ginger family, Zingiberaceae.
In traditional medicine, turmeric is thought to have many healthful properties. It is taken in some Asian countries as a dietary supplement, which allegedly helps with stomach problems and other ailments. It is popular served as a tea in Okinawa, Japan.
A 2004 UCLA-Veterans Affairs study involving genetically altered mice suggests that curcumin, the yellow pigment in curry spice, might inhibit the accumulation of destructive beta amyloids in the brains of Alzheimer's patients and also break up existing plaques. "Curcumin has been used for thousands of years as a safe anti-inflammatory in a variety of ailments as part of Indian traditional medicine," Gregory Cole, Professor of medicine and neurology at the David Geffen School of Medicine at UCLA said.
As an additive (E100)
It is also used in product systems that are packaged to protect them from sunlight. The oleoresin is used for oil-containing products. The curcumin/polysorbate solution or curcumin powder dissolved in alcohol is used for water containing products. Over-colouring, such as in pickles, relishes and mustard, is sometimes used to compensate for fading.
Turmeric has found application in canned beverages, baked products, dairy products, ice cream, yoghurts, yellow cakes, biscuits, popcorn-colour, sweets, cake icings, cereals, sauces, gelatines, direct compression tablets, etc. In combination with Annatto (E160b) it has been used to colour cheeses, dry mixes, salad dressings, winter butter and margarine.
Investigations into the low incidence of colorectal cancer amongst ethnic groups with a large intake of curries compared with the indigenous population have discovered that some active ingredients of turmeric may have anti-cancer properties. Second-stage trials of a turmeric-based drug as a possible treatment for cancer are currently underway.
According to recent research results ,  the component curcumin causes degradation of the human proteine p35. p35 is responsible for the removement of damaged cells that are likely to become tumors. This effect would - in contrary to the reseach activities to use it as a treatment for cancer - increase the risk of developing tumors.
Consuming large doses is not recommended in cases of gallstones, obstructive jaundice, acute bilious colic and toxic liver disorders.
Vicco Labs of India manufactures a popular skin cream formulated with turmeric cream, which it claims to "prevent the penetration of ultra violet rays of the sun into the skin." The Government of Thailand is funding a project to extract and isolate tetrahydrocurcuminoids (THC) from turmeric. THC are colorless compounds that might have antioxidant and skin lightening properties and might be used to treat skin inflammations, making these compounds useful in cosmetics formulations.
Active substance of turmeric is polyphenol curcumin, also known as C.I. 75300, or Natural Yellow 3. Systematic chemical name is (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione. It can exist at least in two tautomeric forms, keto and enol. The keto form is preferred in solid phase and the enol form in solution.