Turmeric (Curcuma longa, Curcuma domestica)

Turmeric, a perennial herb prevalent in South Asia, is ubiquitous in Asian and Middle Eastern cooking. It is also used in Ayurveda and traditional Chinese medicine to treat inflammation, burns, and disorders of the digestive system.

Turmeric was found useful in relieving symptoms associated with irritable bowel syndrome, ulcerative colitis, and osteoarthritis. Epidemiological data indicate that it may improve cognitive performance, but a randomized trial did not find any benefit.

Current evidence from preclinical studies suggests strong chemopreventive potential of curcumin, the active constituent of turmeric, against a variety of tumors. Clinical trials are underway.

Curcumin was shown to interfere with cyclophosphamide in vitro, but a combination of curcumin and docetaxel was found to be safe in a Phase I study. In addition, curcumin enhanced the effects of gemcitabine both in vitro and in vivo. Until definitive data become available, cancer patients should avoid taking turmeric supplements during treatment.

-Barrie Cassileth, PhD

ALSO KNOWN AS: Indian saffron, curcumin, jiang huang.

SUMMARY: Turmeric, a perennial plant native to South Asia, is a key ingredient in Asian and Middle Eastern cuisines. It has also been used in Ayurveda and traditional Chinese medicine to treat bacterial infections, inflammation, burns, and digestive disorders. It is available in supplemental form for gastrointestinal discomfort and as an antiseptic.

Extensive research over the last two decades suggests that it helps to alleviate symptoms of irritable bowel syndrome,[1] ulcerative colitis,[2] and osteoarthritis.[3] Curcumin, a hydrophilic polyphenol constituent of turmeric, elicits strong anti-inflammatory and antioxidant properties and is thought to be responsible for turmeric’s beneficial effects. Data from epidemiologic studies suggest that turmeric may improve cognitive performance,[4] but a randomized trial of patients with Alzheimer’s disease found no such benefits.[5]

Curcumin has been shown to be a promising anticancer agent in several in vitro and animal studies. Proposed mechanisms of action include regulation of transcription factors, growth-regulatory molecules, and growth factor receptors, protein kinase, and tumor suppressor pathways.[6]

In clinical studies, curcumin was well tolerated by cancer patients.[7] While it was shown to significantly inhibit cyclophosphamide-induced tumor regression in a human breast cancer model,[8] results from a phase I trial found a combination of curcumin and docetaxel (Taxotere) to be safe.[9] Curcumin also potentiated the antitumor effects of gemcitabine (Gemzar) in pancreatic cancer.[10] Clinical trials are under way to determine the efficacy of curcumin in patients with pancreatic cancer.

HERB-DRUG INTERACTIONS: Anticoagulants/antiplatelets: Turmeric may increase risk of bleeding.[11]

Camptothecin: Turmeric inhibits campto-thecin-induced apoptosis of breast cancer cell lines in vitro.[8]

Mechlorethamine: Turmeric inhibits me-chlorethamine-induced apoptosis of breast cancer cell lines in vitro.[8]

Doxorubicin: Turmeric inhibits doxorubicin-induced apoptosis of breast cancer cell lines in vitro.[8]

Cyclophosphamide: Dietary turmeric inhibits cyclophosphamide-induced tumor regression in animal studies.[8]

Norfloxacin: Pretreatment with curcumin increased plasma elimination half-life, reducing the dosage of norfloxacin.[12]

Drugs metabolized by CYP3A4 enzyme: Curcumin inhibits cytochrome 3A4 enzyme, altering the metabolism of certain prescription drugs.[13]

Celiprolol and midazolam: Curcumin was shown to downregulate intestinal P-glycoprotein levels, thereby increasing the concentrations of celiprolol and midazolam.[14]

For additional information, visit the Memorial Sloan-Kettering Cancer Center Integrative Medicine Service website, “About Herbs,” at http://www.mskcc.org/AboutHerbs.

References:

REFERENCES

1. Bundy R, et al: Turmeric extract may improve irritable bowel syndrome symptomology in otherwise healthy adults: A pilot study. J Altern Complement Med 10:1015-1018, 2004.

2. Hanai H, et al: Curcumin maintenance therapy for ulcerative colitis: Randomized, multicenter, double-blind, placebo-controlled trial. Clin Gastroenterol Hepatol 4:1502-1506, 2006.

3. Kuptniratsaikul V, et al: Efficacy and safety of Curcuma domestica extracts in patients with knee osteoarthritis. J Altern Complement Med 15:891-897, 2009.

4. Ng TP, et al: Curry consumption and cognitive function in the elderly. Am J Epidemiol 164:898-906, 2006.

5. Baum L, et al: Six-month randomized, placebo-controlled, double-blind, pilot clinical trial of curcumin in patients with Alzheimer disease. J Clin Psychopharmacol 28:110-113, 2008.

6. Ravindran J, et al: Curcumin and cancer cells: How many ways can curry kill tumor cells selectively? AAPS J 11:495-510, 2009.

7. Dhillon N, et al: Phase II trial of curcumin in patients with advanced pancreatic cancer. Clin Cancer Res 14:4491-4499, 2008.

8. Somasundaram S, et al: Dietary curcumin inhibits chemotherapy-induced apoptosis in models of human breast cancer. Cancer Res 62:3868-3875, 2002.

9. Bayet-Robert M, et al: Phase I dose escalation trial of docetaxel plus curcumin in patients with advanced and metastatic breast cancer. Cancer Biol Ther 9:8-14, 2010.

10. Kunnynajjara AB, et al: Curcumin potentiates antitumor activity of gemcitabine in an orthotopic model of pancreatic cancer through suppression of proliferation, angiogenesis, and inhibition of nuclear factor-kappaB-regulated gene products. Cancer Res 67:3853-3861, 2007.

11. Brinker F: Herbal Contraindications and Drug Interactions, 2nd ed. Sandy, OR, Eclectic Medical Publications, 1998.

12. Pavithra BH, et al: Modification of pharmacokinetics of norfloxacin following oral administration of curcumin in rabbits. J Vet Sci 10:293-297, 2009.

13. Zhang W, Lim LY: Effects of spice constituents on P-glycoprotein-mediated transport and CYP3A4-mediated metabolism in vitro. Drug Metab Dispos 36:1283-1290, 2008.

14. Zhang W, et al: Impact of curcumin-induced changes in P-glycoprotein and CYP3A expression on the pharmacokinetics of peroral celiprolol and midazolam in rats. Drug Metab Dispos 35:110-115, 2007.