Turmeric (Curcuma longa, Curcuma domestica)
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, ulcerative colitis, and osteoarthritis. 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, but a randomized trial of patients with Alzheimer’s disease found no such benefits.
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.
In clinical studies, curcumin was well tolerated by cancer patients. While it was shown to significantly inhibit cyclophosphamide-induced tumor regression in a human breast cancer model, results from a phase I trial found a combination of curcumin and docetaxel (Taxotere) to be safe. Curcumin also potentiated the antitumor effects of gemcitabine (Gemzar) in pancreatic cancer. 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.
Camptothecin: Turmeric inhibits campto-thecin-induced apoptosis of breast cancer cell lines in vitro.
Mechlorethamine: Turmeric inhibits me-chlorethamine-induced apoptosis of breast cancer cell lines in vitro.
Doxorubicin: Turmeric inhibits doxorubicin-induced apoptosis of breast cancer cell lines in vitro.
Cyclophosphamide: Dietary turmeric inhibits cyclophosphamide-induced tumor regression in animal studies.
Norfloxacin: Pretreatment with curcumin increased plasma elimination half-life, reducing the dosage of norfloxacin.
Drugs metabolized by CYP3A4 enzyme: Curcumin inhibits cytochrome 3A4 enzyme, altering the metabolism of certain prescription drugs.
Celiprolol and midazolam: Curcumin was shown to downregulate intestinal P-glycoprotein levels, thereby increasing the concentrations of celiprolol and midazolam.
For additional information, visit the Memorial Sloan-Kettering Cancer Center Integrative Medicine Service website, “About Herbs,” at http://www.mskcc.org/AboutHerbs.
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