Turmeric is indigenous to the tropical regions of southern Asia. It is widely used as a yellow food color and spice, including an ingredient in curry powder, throughout India, China, and Indonesia. It is also popular in Asian traditional medicine, even though there is no known basis for all of its many varied uses in folk healing.

However, both in vitro and in vivo pharmacological studies show that turmeric and its active constituents have antioxidant, antitumor, anti-inflammatory, and antimicrobial effects. In in vivo research, turmeric extracts displayed antitumor activity against skin cancer, breast cancer, and oral cancer cell lines. Turmeric extracts thus may be clinically beneficial in treating a range of carcinomas in humans.

Turmeric is also a cholagogue, an agent that stimulates the flow of bile from the duodenum. It has choleretic actions that enhance bile secretion by the liver as well as cholecystokinetic properties that promote gallbladder contraction. It is also an antihepatotoxic agent.

Turmeric is an erect, perennial plant distinguished by its oblong tubers and by its large, petioled leaves that are tapered at each end. The dull, yellowish white or yellow flowers radiate from a stem encased in a sheathing petiole. The cone-shaped, tubular infloresences are about four to six inches long with a three-lobed calyx.

The palate tubers have a characteristically yellowish-brown exterior and a deep orange or reddish-brown interior. Each tuber gives rise to multiple, secondary, finger-shaped, tuber-like rhizomes that bear no offshoots of their own. Turmeric has a noticeable fragrance, and its bitter, mildly acrid taste is reminiscent of ginger. The dried rhizomes have a transversely ringed appearance.

• Tubers
• Dried rhizome

Volatile oil (4 to 14%, 60% sesquiterpene ketones, or tumerones, including alpha-tumerone, beta-tumerone, artumerone, alpha-atlantone, gamma-atlantone, curlone, zingiberene, curcumol); curcuminoids (curcumin [diferuloylmethane], bidemethoxycurcumin, demethoxycurcumin); 1,5-diaryl-penta-1,4-dien-3-on- derivatives; sugars.

Turmeric is typically available as hydroalcoholic fluid extracts, tinctures, and encapsulated powders. Decoctions are rarely employed since both the volatile oil and curcuminoids are not particularly water soluble. All turmeric products should be protected from light when stored.

Internal: liver obstruction, jaundice, intestinal worms, fever, diarrhea, bronchitis, leprosy, headache, arthritis, menstrual complaints, toothache, hemorrhage, stomach tonic, blood purifier, antifertility agent, insect repellent.

External: ulcers, inflammation, wounds, bruises, eye infections, leech bites.

Conditions: liver and gallbladder disorders; loss of appetite, dyspepsia.

Clinical applications: dyspeptic complaints, liver toxicity, hyperlipidemia inflammation, tumors; antioxidant, anti-inflammatory, and antimicrobial agent.

In in vitro studies, both turmeric extracts and curcumin exhibited significant antioxidant and free radical scavenging activity at least comparable to that of vitamins C and E. Turmeric inhibited oxidative insults in vivo and in vitro by interrupting oxidative chain reactions caused by free radicals. The volatile oil and alcohol extracts suppressed microbial growth of numerous bacterial and fungal pathogens in vitro.

Aqueous turmeric extracts produced antimutagenic action against several mutagens in test animals. In clinical studies, smokers administered oral doses of 1 to 5 g turmeric daily for 30 days showed significantly lower levels of mutagens in their urine when compared to nonsmokers given placebo.

Turmeric also has cardiovascular, hepatic, and gastrointestinal actions. Curcumin and turmeric, even in small doses, reduced cholesterol levels and inhibited platelet aggregation in vivo. Curcumin decreased cholesterol levels by several mechanisms: disrupting cholesterol uptake from the intestines, increasing the transformation of cholesterol into bile acids, and promoting choleretic action leading to increased excretion of bile acid.

The volatile oil is responsible for the choleretic action, while the curcuminoids account for the anti-inflammatory and cholekinetic properties of turmeric. Curcumins presumably block platelet aggregation by suppressing the formation of thromboxanes and simultaneously elevating prostacyclin levels.

Turmeric decreased symptoms of skin cancers and reduced the incidence of chemically caused breast cancer in laboratory animals. Curcumins exhibit anticancer activity during the tumor initiation, promotion, and progression stages of development.

Combinations of curcumin and genistein, an isoflavone derived from soy, may help to combat breast cancer. In an in vitro experiment, curcumin/genistein mixtures had a synergistic effect on inhibiting the pesticide-induced proliferation of estrogen-positive cells. In another study, curcumin administered i.p. to female rats suppressed DMBA-induced mammary tumorigenesis in the test animals.

The volatile oil fraction of turmeric showed anti-inflammatory properties in several studies. Curcumin was comparable to either cortisone or phenylbutazone in eliciting anti-inflammatory effects without adverse side effects in in vivo models of acute inflammation, but only 50% as effective in chronic inflammation.

• Standardized powder (curcumin): 400 to 600 mg tid (1.5 to 3.0 g daily) 
• Tincture (1:2): 3 to 5 ml tid 

Note: Curcumin should be taken on an empty stomach 20 minutes before meals or between meals. Oral doses of curcumin are not readily absorbed; 40 to 85% of the compounds may never be absorbed in the gastrointestinal tract. Combinations of curcumin and bromelain may increase the absorption of curcumin.

Turmeric and curcumin are safe when taken in recommended doses. However, extended oral use of curcumin occasionally produces gastrointestinal upset and, in extreme cases, ulcers.

Warnings/ Contraindications/Precautions

Excessive dosing of standardized curcumin products may lead to gastric complaints and possibly ulcers. Patients diagnosed with either gallstones or obstruction of bile passages should consult a qualified health care practitioner before using turmeric products.

Although components of turmeric root have potently inhibited the cytochrome P450 enzyme system in rat liver (Oetari et al. 1996), specific interactions between this herb and conventional medications metabolized via the P450 system are not known to have been documented in the literature to date.

Ethanol extracts of turmeric root (500 mg/kg) inhibited gastric secretion and protected gastroduodenal mucosa against injuries caused by drugs such as indomethacin (30 mg/kg po) and reserpine (5 mg/kg IM) in rats (Rafatullah et al. 1990).

Commission E classifies turmeric as an approved drug for use as a cholagogue and digestive aid.

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