Curcuma longa : Folklore or Medical Marvel?

Records dating as far back as 600BC note that turmeric can cure anything from a sore throat to cancer. But are these just old wives’ tales or is turmeric as medically useful as they claim..?

Curcuma longa is a perennial herb from the Zingiberaceae family. It is thought to be native to the Indian subcontinent and can be grown throughout the tropical and subtropical regions. C. longa is most widely cultivated in China and India.
Turmeric, the powdered form of the rhizome, is a very popular ingredient in Indian and Asian cooking. The distinctive yellow colour of the spice comes from the compound curcumin. Curcumin has been reported to have therapeutic properties that can help protect against a wide range of diseases.

A rather sad looking Curcuma longa from the Tropical greenhouse

A rather sad looking Curcuma longa from the Tropical greenhouse. This species dies back in the winter months and goes into partial dormancy.

What does it look like? – Species Description
The distinctive features of C. longa are the branched rhizomes which have bright yellow flesh. The rhizomes are aromatic and are cylindrical in shape. The herb can grow up to 1m tall, with green oblong leaves that are glabrous, with an acuminate apex. The inflorescences are cylindrical spikes, terminal on pseudostems. Fertile bracts are ovate and pale green in colour. The calyx is white, puberulent and 3-toothed at the apex and the corolla is pale yellow. The anther is spurred at the base and the ovary is slightly hairy (Flora of China).

Here are three properties of  curcumin that can help in the treatment of a number of diseases.

 

Antioxidative Properties
Antioxidants are compounds that protect the body against free radicals. Free radicals are molecules that can be formed as a waste product of the body’s metabolism (Menon and Sudheer, 2007). These free radicals are very unstable and can be very reactive, causing oxidative stress to the body’s cells and DNA. This damage to the cells can be a major role in the development of a number of diseases including cardiovascular diseases, neurodegenrative diseases (such as Alzheimer’s disease) and cancer (Ratnam et al., 2006).
Curcumin is considered the most active agent in C. longa, and is responsible for turmeric’s antioxidative properties. Curcumin is a type of agent known as a phenolic compound, Chemical structure of curcuminwhich is made up of one or more aromatic phenol ring with at least one hydroxyl group replacing a carbon atom (Manach et al., 2004). A hydrogen atom from one of the hydroxyl groups in curcumin is donated to the free radical, allowing it to

Chemical structure of curcumin

become stable. By becoming stable, the free radical molecules can no longer damage the body’s cells.

Anti-inflammatory Properties
Studies have shown that curcumin has anti-inflammatory properties and can be effective as a therapy for inflammatory bowel diseases (Holt, Katz and Kirshoff, 2005). Inflammatory bowel diseases (IBDs) are a group of diseases that cause inflammation in the gastrointestinal tract. The most common IBDs are Crohn’s Disease and ulcerative colitis. In Crohn’s disease the inflammation can occur at any part of the gastrointestinal tract but is most commonly occurring in the small bowel. However, ulcerative colitis only occurs in the colon (Oxford Medical Dictionary). In individuals with an IBD, the mucus lining of the gastrointestinal (GI) tract is thinner. This makes it difficult for bacteria to be removed from the wall of the intestine. The build up of unwanted bacteria causes that segment of the GI tract to become inflamed (Shanahan, 2002). The inflammation triggers the expression of IL-2, a signalling protein that is involved in the body’s immune response. IL-2 signals for CD4+ cells to be produced, which are responsible for sending signals to other immune cells, including CD8 which destroy viruses.
Curcumin has an anti-inflammatory effect on the body by inhibiting the production of IL-2. Curcumin also controls the expression of CD4+ cells to result in the immune response being halted, therefore limiting the inflammation response (Forward et al., 2011).

Anticancer Properties
Rapid cell division is a key feature of the aggressive growth of cancer. Cell proliferation requires growth factors to be produced, the signal for which is generated from the interaction of cells with neighbouring cells. However, cancer cells can produce their own growth factors, such as epidermal growth factor which has been found in fast growing prostrate cancer. Curcumin can suppress the production of these growth factors by blocking the pathway that the growth factor uses to intiate cell division (Pongrakhananon and Rojanasakul, 2011).
Curcumin can also control the damaging growth of cancer cells by generating cell death, also known as apoptosis (Chattopadhyay et al., 2004). Apoptosis is part of the normal cycle in the cell tissue development. Apoptosis can be triggered by a group of proteins (Bcl-2) which releases cytochrome c (another protein) from mitochondria in the body’s cells. The cytochrome c protein then activates a series of enzymes called caspases, which induce cell death (Kotake-Nara et al., 2005). Cancer cells have a resistance to cell death, however, curcumin can override this and triggers this series of reaction in the cancer cells (Pongrakhananon and Rojanasakul, 2011).

This is only a small handful of the studies that are being carried out to investigate the medicinal properties of C. longa. And more are on the way.  The evidence is stacking up that these old wives tales really are true, and Western medicine is finally catching up to what many cultures discovered centuries ago.

An apple a day keeps the doctor away…but maybe try a curry once in a while too.

References

Ak, T.; Gülçin, I., 2008. Antioxidant and radical scavenging properties of curcumin. Chemico-Biological Interactions. Vol. 174 p. 27-37

Chattopadhyay, I.; Biswas, K.; Bandyopadhyay, U.; Banerjee, R., 2004. Turmeric and curcumin: Biological actions and medical applications. Current Science. Vol. 87 p. 44-53

Forward, N.A.; Conrad, D.M.; Power Coombs, M.R.; Doucette, C.D.; Furlong, S.J.; Lin, T.; Hoskin, D.W., 2011. Curcumin blocks interleukin (IL)-2 signalling in T-lymphocytes by inhibiting IL-2 synthesis, CD25 expression, and IL-2 receptor signalling. Biochemical and Biophysical Research Communications. Vol. 407 p. 801-806

Holt, P.R.; Katz, S.; Kirshoff, R., 2005. Curcumin Therapy in Inflammatory Bowel Disease: A Pilot Study. Digestive Diseases and Sciences. Vol. 50 p. 2191-2193

Jurenka, J.S., 2009. Anti-inflammatory Properties of Curcumin, a Major Constituent of Curcuma longa: A Review of Preclinical and Clinical Research. Alternative Medicine. Vol. 14 p. 141-153

Kotake-Nara, E.; Terasaki, M.; Nagao, A., 2005. Characterization of Apoptosis Induced by Fucoxanthin in Human Promyelocytic Leukemia Cells. Biosci. Biotechnol. Biochem. Vol. 69 p. 224-227

Manach, C.; Scalbert, A.; Morand, C.; Rémésy, C.; Jiménez, L., 2004. Polyphenols: food sources and bioavailability. American Journal of Clinical Nutrition. Vol. 79 p. 727-747

Menon, V.P.; Sudheer, A.R., 2007. Antioxidant and anti-inflammatory properties of curcumin. Advances in Experimental Medicine and Biology. Vol. 595 p. 105-125

Oxford Concise Medical Dictionary, 8th Ed., 2010. Published by Oxford University Press, Oxford. p. 178

Ratnam, D.V.; Ankola, D.D.; Bhardwaj, V.; Sahana, D.K.; Ravi Kumar, M.N.V., 2006. Role of antioxidants in prophylaxis and therapy: A pharmaceutical perspective. Journal of Controlled Release. Vol. 113 p. 189-207

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