It's now pretty well known that Turmeric is not just something that gives the yellow colour to Indian curries. It is said to possess a range of important biological activities; among these, the most important, and the most researched, are two:
- Antibacterial activity
- Antioxidant and Anti-inflammatory activtiy
And it's also well known that the key ingredient in Turmeric that brings about these activities is the compound Curcumin.
There are two other 'Curcuminoids' that occur together with Curcumin - formed by the progressive removal of one, and two, of the methoxy groups from Curcumin. These are named Demethoxycurcumin and bis Demothoxycurcumin respectivley:
Turmeric, of course, is a rhizome; and the typical Curcuminoid content in the root is less than 3%. No other part of the plant is reported to have the compound, it's all just in the root. Of course, there are extracts and dietary supplements available in the market that have high Curcumin content.
The chemical structure of Curcumin is rather simple, but this simplicity seems to belie its biochemical capabilities. In literature, the main structural features of the compound that make the biochemical interactions possible are reported to be:
- The two central, conjugated diketo groups, which are involved in protein interactions and chelation with metal ions, and
- The two phenolic hydroxyl groups, which contribute to the antioxidative property
One 'less-than-desirable' property of Curcumin is said to be its chelation to iron in-vivo - possibly leading to anaemic conditions. Another is its low oral bioavailability - it is reported that very little Curcumin taken orally is absorbed by the human body, although there are conflicting studies about this.
In subsequent episodes of this article, we will look at the chemical aspects of the biological activities of curcumin as reported in literature - and also review studies on the theoretical (molecular orbital) bases for these activities .
- Wikipedia on Turmeric
- Curcumin Content of Turmeric and Curry Powders, Reema F. Tayyem, Dennis D. Heath, Wael K. Al-Delaimy, and Cheryl L. Rock, Nutrition and Cancer, 55(2), 126–13, 2006
- The Biological Activity of Curcumin, Oliver Shulz, Wellnes Foods Europe, 10, July 2008