curcumin

Curcumin (diferuloylmethane) is a bright yellow chemical produced by some plants. It is the principal curcuminoid of turmeric (Curcuma longa), a member of the ginger family (Zingiberaceae). It is sold as an herbal supplement, cosmetics ingredient, food flavoring and food coloring. As a food additive, its E number is E100.
It was isolated in 1815 when Vogel and Pelletier reported the isolation of a “yellow coloring-matter” from the rhizomes of turmeric and named it curcumin. Although curcumin has been used historically in Ayurvedic medicine, there is no evidence from clinical research that it has medicinal properties.
Chemically, curcumin is a diarylheptanoid, belonging to the group of curcuminoids, which are natural phenols responsible for turmeric's' yellow color. It is a tautomeric compound existing in enolic form in organic solvents and as a keto form in water.