Curcumin, the natural pigment that gives the spice turmeric its yellow color, has come under the scientific spotlight in recent years, with studies investigating its cancer-fighting abilities published in journals on a monthly basis.
Swansea's team of scientists, led by Professor John Baxter and Dr Gareth Jenkins, was spurred into its particular line of enquiry by the observation of a much lower rate of cancers of the esophageal tract in India, where spices such as turmeric form an important part of the diet.
However it is recommended that consumers wishing to make use of curcumin's properties consume it in supplement form rather than eating more curries, which tend to be rather high in fat in their Western form.
Professor Baxter and Dr Jenkins have already obtained data indicating that curcumin can block a key protein associated with esophageal cancer, known as NF-kappaB.
Dr Jenkins told NutraIngredients-USA.com that this data has yet to be published, and that the team hopes to obtain more of an insight into the precise mechanism at work prior to submitting to a peer-reviewed journal later this year.
Professor Baxter called the discovery "a shot in the arm for our research," and said that by identifying ways to suppress NF-kappaB activity, the team's ultimate aim is to be able to block GI-tract cancer development.
Funding to the tune of £11,000 pounds plus a surgeon's salary pledged by Swansea's Morriston Hospital's Research and Development Office is a step in the right direction, as it will facilitate a pilot study investigating the effects of curcumin in lowering the NF-kappaB levels in patients suffering from Barrett's esophagus, a pre-malignant form of esophageal cancer that leads to the full-blown disease in around ten percent of cases.
Approval to proceed has not yet been granted by the local research ethics committee, but Dr Jenkins said: "Because it is a common dietary agent and no papers have been published suggesting it is a toxic, I don't think it will be a problem."
The study will involve 40 to 50 patients with Barrett's esophagus, who will take curcumin supplements for just a few days. Between five and seven days later, their NF-kappa-B levels will be measured by an endoscopy and compared with those of a control group.
The curcumin dosage used is likely to be 500g tablets, since these are readily available from health food stores.
"We don't expect long lasting effects in these participating patients from taking curcumin for just a few days," said Dr Jenkins, "but if the results are very promising it may be appropriate to a larger study over a few years."
The progress at Swansea is in keeping with consensus from other scientists in the field. A review of the evidence, published in the European Journal of Cancer this month (2005; Aug 1) concluded that "Sufficient data currently exist to advocate phase II clinical evaluation of oral curcumin in patients with invasive malignancy or pre-invasive lesions of the gastrointestinal tract, particularly the colon and rectum."
However Dr Jenkins said that the major problem with Barrett's esophagus is that in 90 percent of patients never develops into cancer, and although some speculation as to dietary and drug history, the reason why this is so is not really known.
Barrett's esophagus is cause by acid reflux, and although it can occur early in life, most sufferers are in their 40s and 50s. Dr Jenkins said that the patients who develop cancer tend to be older, but that there are always exceptions.
There are surgical and pharmaceutical ways to reduce acid reflux, but no firm link has been made between these, Barrett's esophagus and esophagal cancer.
Other recent research into the curcumin's anti-cancer effects include a study published in this month's issue of Cancer (DOI: 10.1002/cncr.21216), which found that it inhibits melanoma cell growth and kills tumor cells.
In June researchers at the Department of Experimental Therapeutics at the University of Texas reported that curcumin helped stop the spread of breast cancer tumor cells to the lungs in a mice trial.
The agent is also being tested against multiple myeloma and pancreatic cancer in early phase I clinical trials at the University of Texas M.D. Anderson Cancer Center in Houston, and in May Wake Forest University Baptist Medical Center to research turmeric and propolis.
The Wake Forest research will focus on the use of curcumin and caffeic acid phenethyl ester, a compenent in propolis, to boost the effects of enhance radiation therapy for brain tumors, and unraveling how they may make tumor cells more sensitive to radiation, while protecting normal tissue.