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- Turmeric (Curcuma longa)
- Curcumin
- Potential Therapeutic Uses
| Date:
05-31-2012 | HC# 021237-449
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Re: Curcumin Exhibits Potential in the Treatment of Various Chronic Diseases
Gupta SC, Patchva S, Koh W,
Aggarwal BB. Discovery of curcumin, a component of golden spice, and its
miraculous biological activities. Clin
Exp Pharmacol Physiol. 2012 Mar;39(3):283-299.
The medicinal properties of turmeric (Curcuma longa), the source of curcumin,
have been known for thousands of years, but advancements in modern science have
provided a scientific basis for using curcumin therapy against numerous human
diseases. In this article, the authors discuss the discovery and key biological
activities of curcumin, particularly its activities at the molecular and
cellular levels, as well as in animals and humans.
The discovery of curcumin dates back 2 centuries
ago when Vogel and Pelletier1 isolated "yellow colouring
matter" from the rhizomes of turmeric and named it curcumin (the word
curcumin stems from the Persian word "kurkum" [curcuma], which means
saffron). Later, the substance was found to be a mixture of resin and turmeric
oil. For several decades, chemists reported possible structures of curcumin;
however, in 1910, the chemical structure of curcumin was identified as
diferuloylmethane or 1,6-heptadiene-3,5-dione-1,7-bis(4-hydroxy-3-methoxyphenyl)-(1E,6E).
Although turmeric has been used as a dietary
spice and a cure for human ailments for thousands of years in Asian countries,
the biological characteristics of curcumin were not identified scientifically
until the mid-20th century. In a paper2 published in Nature in 1949, the authors reported
that curcumin was active against strains of Staphylococcus
aureus, Salmonella paratyphi, Trichophyton gypseum, and Mycobacterium tuberculosis. In the
1970s, the cholesterol-lowering, antidiabetic, anti-inflammatory, and
antioxidant activities of curcumin were reported, and in the 1980s, its anticancer
activity in both in vitro and in vivo models was reported.3 By 1995,
anti-inflammatory activity and the mechanisms involved were elucidated by the
authors.4
Although curcumin is effective against many
human ailments, it has poor bioavailability, apparently due to its poor
absorption, rapid metabolism, and rapid systemic elimination. Efforts have been
made to improve its bioavailability by improving these factors. In spite of
these limitations in bioavailability, as little as 150 mg curcumin administered
twice a day orally in humans (n=23) was sufficient to lower serum levels of
inflammatory biomarkers such as endothelin-1, interleukin-6, tumor necrosis
factor-α and malondialdehyde levels.5
Curcumin is now regarded as a "new
drug" with great potential and is being used as a supplement and marketed
in several forms, including capsules, tablets, ointments, energy drinks, soaps,
and cosmetics.
Curcumin has been shown to modulate various
signaling molecules, including inflammatory molecules, transcription factors,
enzymes, protein kinases, protein reductases, carrier proteins, cell survival
proteins, drug resistance proteins, adhesion molecules, growth factors, receptors,
cell cycle regulatory proteins, chemokines, DNA, RNA, and metal ions. Curcumin
may cause up- or downregulation, depending on the target and cellular context.
These targets fall into 2 categories: those to which curcumin binds directly
and those whose activity is modulated indirectly by curcumin; both of these
areas are extensively covered in review articles. Among the most important
targets of curcumin are the pro-inflammatory transcription factors, which
regulate the expression of genes that contribute to tumorigenesis, cell
survival, cell proliferation, invasion, and angiogenesis. Another important
target is the protein kinases.
Because it modulates multiple signaling
molecules, curcumin has been reported to possess pleiotropic activities. In
vitro, it has been shown to possess anti-inflammatory, antioxidant,
pro-apoptotic, chemopreventive, chemotherapeutic, antiproliferative, wound
healing, antinociceptive, antiparasitic, and antimalarial properties.
Curcumin has also been shown to have activity
as an antioxidant and free radical scavenger in several in vitro studies. This
activity is due to either the hydroxyl group or the methylene group of the α-diketone
(heptadiene-dione) moiety. It is also cytotoxic to cancer cells, via the
mechanism of apoptosis, and has wide antimicrobial activity.
In animal studies, curcumin has been found to
be active against diabetes, obesity, neurological and psychiatric disorders
(such as depression, Alzheimer's disease, and Parkinson's disease), and cancer
(particularly colon cancer) and cancer-related symptoms such as fatigue,
neuropathic pain, and cognitive deficit. It has also shown potential against
chronic illnesses affecting the eyes, lungs, liver, kidneys, and
gastrointestinal and cardiovascular systems.
About 50 clinical trials have been completed on
curcumin's potential in humans. Most have suggested that curcumin is safe and
effective to treat a number of diseases, with the most promising effects
observed with cancer, inflammatory conditions, skin, eye and neurological
disorders, diabetic nephropathy, and pain. Other trials have investigated the
role of curcumin in improving body weight and reducing lipid levels in patients
with acute coronary syndrome. At the time of this article's preparation,
curcumin was undergoing investigation in more than 30 clinical trials, say the
authors, adding, "We expect that the completion of these clinical trials
will provide further credence to the already established positive effects of
curcumin."
Curcumin has not yet been approved to treat
any human diseases, say the authors, who suggest that more extensive and
well-controlled human studies are needed to demonstrate its safety and
efficacy. "Future research should be focused on bringing this fascinating
molecule to the forefront of therapeutic agents for the treatment of human
diseases," they write.
—Shari Henson
References
1Pelletier J, Vogel A. Examen chimique de la
racine de Curcuma. J Pharm. 1815;i:289-300.
2Schraufstatter E, Bernt H. Antibacterial
action of curcumin and related compounds. Nature.
1949:164(4167):456-457.
3Kuttan R, Bhanumathy P, Nirmala K, George MC.
Potential anticancer activity of turmeric (Curcuma
longa). Cancer Lett. 1985;29(2):197-202.
4Singh S, Aggarwal BB. Activation of
transcription factor NF-kappa B is suppressed by curcumin (diferuloylmethane) [corrected]
[published erratum appears in J Biol Chem.
1995;270(50):30235]. J Biol Chem.
1995;270(42):24995-25000.
5Usharani P, Mateen
AA, Naidu MU, Raju YS, Chandra N. Effect of NCB-02, atorvastatin and placebo on
endothelial function, oxidative stress and inflammatory markers in patients
with type 2 diabetes mellitus: a randomized, parallel-group, placebo-controlled,
8-week study. Drugs R D.
2008;9(4):243-250.
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