- Indian saffron
- Jiang huang
For Patients & Caregivers
How It Works
Turmeric demonstrated anti-inflammatory and anticancer activities in lab studies. A few studies suggest that curcumin has biological activity in some cancer patients but more data are needed to verify its benefits.
Turmeric is a spice that has been used in cooking for centuries. Scientists have determined that turmeric has many biological activities, although they do not fully understand exactly how it exerts these effects. From laboratory experiments, it has been deduced that substances in turmeric (called curcuminoids) prevent inflammation by inhibiting the molecules that mediate inflammatory reactions. Curcuminoids may protect the body in a few ways: they enhance the activity of an important detoxifying enzyme and they also act as antioxidants by neutralizing free radicals (which can cause DNA damage). In rats, turmeric prevented the development of kidney damage from toxins. Turmeric also stimulates the flow of bile in the gastrointestinal tract.
In rats exposed to cancer-causing substances, those that were treated with turmeric were protected from colon, stomach, and skin cancers. Turmeric also stops the replication of tumor cells when applied directly to them in the laboratory, but it is unknown if this effect occurs in the human body. Curcumin, a curcuminoid, has shown biological activity in pancreatic cancer patients and there are ongoing studies to test its effect as an addition to current cancer treatment. However, recent experiments have suggested that turmeric might interfere with the activity of some chemotherapy drugs in breast cancer, so the question remains whether this spice is helpful or harmful during chemotherapy. Curcumin also showed weak phytoestrogenic activity in a laboratory study. Human data are needed.
- To prevent cancer
Several animal studies suggest that turmeric prevents colon, stomach, and skin cancers in rats exposed to carcinogens.
- To treat infections
One clinical trial showed that turmeric does not help lower viral load in HIV positive patients.
- To reduce inflammation
Laboratory and animal studies suggest that turmeric reduces inflammation. There are ongoing clinical trials on this effect in humans.
- To treat kidney stones
No scientific evidence supports this use.
- To relieve stomach and intestinal gas
No clinical trials have evaluated this use.
- Recent laboratory findings indicate that dietary turmeric may inhibit the antitumor action of chemotherapeutic drugs such as cyclophosphamide and doxorubicin in treating breast cancer. More research is necessary, but patients undergoing chemotherapy should ask their doctor if they should limit their intake of turmeric and turmeric-containing foods.
Do Not Take If
- You have bile duct obstruction, gallstones, predisposition to kidney stones, or gastrointestinal disorders such as stomach ulcers and hyperacidity disorders.
- You are taking reserpine: Turmeric may lessen its effects.
- You are taking indomethacin: Turmeric may lessen its effects.
- You are taking warfarin or other blood thinners: Turmeric may increase your risk of bleeding.
- You are taking chemotherapy drugs such as camptothecin, mechlorethamine, doxorubicin, or cyclophosphamide: Turmeric inhibits the action of these drugs against breast cancer cells in lab experiments.
- You are taking norfloxacin: Curcumin makes this stay in the blood for a longer time, thereby reducing the need for taking higher amounts of the drug.
- You are taking drugs metabolized by CYP3A4 enzyme: Curcumin inhibits cytochrome 3A4 enzyme, altering the metabolism of certain prescription drugs.
- You are taking drugs metabolized by CYP1A2 enzyme: Curcumin inhibits cytochrome 1A2 enzyme, altering the metabolism of certain prescription drugs.
- You are taking drugs metabolized by CYP2A6 enzyme: Curcumin enhances cytochrome 2A6 enzyme, altering the metabolism of certain prescription drugs.
- You are taking drugs transported by P-Glycoprotein: Curcumin affects intestinal P-glycoprotein levels and function, thereby increasing the concentrations of prescription drugs such as celiprolol, midazolam and verapamil.
- You are undergoing certain laboratory tests that use dyes: Curcumin may interfere with some laboratory tests due to its strong absorptive and fluorescent properties.
- You are taking tacrolimus: Curumin supplements increase the plasma level of tacrolimus and may increase the side effects.
For Healthcare Professionals
Turmeric is a plant that is native to South Asia but is cultivated in tropical areas around the world. The rhizome is used as a spice in regional cuisines, and as a coloring agent in food and cosmetics for its yellow-orange color. It is also used in traditional medicine for improving circulation and digestion. Turmeric extracts are marketed as dietary supplements to improve memory, for arthritis, and for cancer prevention.
The active constituents are turmerone oil and water-soluble curcuminoids, mainly curcumin which is the focus of most research. In vitro studies suggest that curcumin, the principal bioactive ingredient of turmeric, acts as a weak phytoestrogen (1), and exhibits neuroprotective (2), choleretic (3), anti-inflammatory (4), immunomodulatory (5), anti-proliferative (3), and chemopreventive effects (6) (7) (8). Curcumin, its analogs, and liposomal formulations have also produced chemosensitizing (9) (10) (11) and radiosensitizing effects (12) (13).
Turmeric and its active constituents have been investigated for their therapeutic activities in humans. Data from an epidemiological study suggest improved cognitive performance in elderly Asians who consume turmeric in the form of curry powder (14); however, no benefits from curcumin supplementation were detected in patients with Alzheimer’s disease (15). Turmeric may help alleviate symptoms of irritable bowel syndrome, (16) quiescent ulcerative colitis (17), and may be effective against major depressive disorder (62). Turmeric extract was found to be safe and equally effective as a non-steroidal anti-inflammatory drug for the treatment of osteoarthritis of the knee (18). Whether curcumin supplementation increases cholesterol levels is unclear, as study results are mixed (19) (20). In a study of postmenopausal women, consumption of curcumin along with aerobic exercise training were shown to improve vascular endothelial function (61).
Turmeric also has anticancer effects. In patients with colorectal cancer, oral curcumin administered during the pre-surgery waiting period improved cachexia and the general health of patients (21). In a phase II trial of oral curcumin in patients with advanced pancreatic cancer, no treatment-related toxic effects were observed, and clinically relevant biological activity was seen in two patients despite limited absorption (22). In another study, supplementation with a blend of green tea, pomegranate, broccoli and curcumin resulted in a reduction in the rate of prostate-specific antigen (PSA) increase among men with prostate cancer following a PSA relapse post-radical treatment (65).
In early phase studies, a combination of curcumin and docetaxel was shown to be safe (23). Curcumin with gemcitabine was also found to be safe and feasible for further study (24) (25), but a high-dose of curcumin must be used to achieve systemic effect (23) (25).
Preliminary data suggest effectiveness of a topical turmeric-based cream for reduction of radiotherapy-induced dermatitis in patients with head and neck cancer (64).
Curcumin is known to interfere with cytochrome P450 enzymes (26) (27) and may interact with chemotherapy drugs like cyclophosphamide and doxorubicin (28). Overall, the development of turmeric for clinical use needs further investigation due to its inherent poor absorption, rapid metabolism, complex mechanistic profile, and largely preclinical data.
Mechanism of Action
The hepatoprotective effects of curcumin, the most researched active constituent in turmeric, may occur via MMP-13 induction and TGF-alpha inhibition (30), as well as anti-apoptotic/anti-necrotic mechanisms (31). However, it has also been shown to inhibit cell-cycle progression during normal liver regeneration (3).
A meta-analysis of randomized clinical trials revealed that curcumin is effective in decreasing the concentration of tumor necrosis factor-alpha, a key mediator in many inflammatory diseases (68). In vitro and animal studies of lung models point to anti-proliferative and modulatory mechanisms involving inhibition of the signal transducer and activator of transcription 3 Stat3 pathway (32), matrix metalloproteinase, and vascular endothelial growth factor (33); caspase- and mitochondria-dependent apoptosis (34) (35); and cyclin-dependent kinase downregulation (35). Curcumin also appears to have synergistic effects with isoflavones, suppressing the prostate-specific antigen (PSA) production in prostate cells through anti-androgen effects (36).
Studies done on breast cancer show that curcumin may inhibit chemotherapy-induced apoptosis via inhibition of the c-Jun NH2-terminal kinase (JNK) pathway and generation of reactive oxygen species (ROS) (28). Data also suggest that curcumin induces apoptosis in human colon cancer cells independent of p21 expression (39). Curcumin’s antitumor actions appear to be due to its interactions with arachidonate metabolism and its in vivo antiangiogenic properties (14). Another possible chemopreventive mechanism maybe via binding and activating the vitamin D receptor (VDR), thereby protecting the small intestine and colon where VDRs are expressed and vitamin D is known to serve an anticancer function (38). Curcumin also inhibited growth of uterine leiomyosarcoma cells by targeting the AKT-mTOR (RAC-alpha serine-threonine-protein kinase; mTOR (mammalian target of rapamycin) pathway (37). And recent findings indicate that curcumin inhibits progression of bladder cancer by down-regulating the expression of beta-catenin, high levels of which are associated with several cancers (69).
Another study found that CRM1, an important nuclear exportin, is a cellular target of curcumin; and that the inhibition of nuclear traffic by curcumin may be responsible for its many biological effects (63).
- Laboratory findings indicate that dietary turmeric may inhibit the anti-tumor action of chemotherapeutic agents such as cyclophosphamide (28).
- Curcumin may also interact with drugs that are substrates of P-glycoprotein (P-gp) (47) (48) or cytochrome P450 enzymes (48) (49).
- Patients with gastrointestinal disorders or predisposed to kidney stone formation (50) should also use this supplement with caution.
Anticoagulants / Antiplatelets: Turmeric may increase risk of bleeding, as it also has antiplatelet properties (54) (55) (66).
Camptothecin: Turmeric inhibits camptothecin-induced apoptosis of breast cancer cell lines in vitro (28).
Mechlorethamine: Turmeric inhibits mechlorethamine-induced apoptosis of breast cancer cell lines in vitro (28).
Doxorubicin: Turmeric inhibits doxorubicin-induced apoptosis of breast cancer cell lines in vitro (28).
Cyclophosphamide: Dietary turmeric inhibits cyclophosphamide-induced tumor regression in animal studies (28).
Norfloxacin: Pretreatment with curcumin resulted in increased plasma elimination half-life, thereby reducing the dosage of norfloxacin (56).
Amphotericin B: Curcumin may enhance the effect and decrease the toxicity of amphotericin B (57).
Drugs metabolized by CYP3A4 enzyme: Curcumin inhibits cytochrome 3A4 enzyme, altering the metabolism of some prescription drugs (26). But according to conflicting data, short-term use of curcumin may not result in a clinically relevant interaction (67).
Drugs metabolized by CYP1A2 enzyme: Curcumin inhibits cytochrome 1A2 enzyme, affecting the metabolism of certain prescription medicines (27).
Drugs metabolized by CYP2A6 enzyme: Curcumin enhances cytochrome 2A6 enzyme, and can affect the metabolism of certain prescription drugs (27).
Celiprolol and Midazolam: Curcumin was shown to downregulate intestinal P-gp levels, thereby increasing the concentrations of celiprolol and midazolam (48).
Verapamil: Curcumin inhibited intestinal P-gp expression and function, thereby increasing concentrations of verapamil (47).
Tacrolimus: Pretreatment with turmeric increases the plasma levels of tacrolimus (59).
Acetaminophen: The cytotoxic effects of curcumin increased significantly in the presence of Acetaminophen (60).
Ibuprofen: The cytotoxic effects of curcumin increased significantly in the presence of ibuprofen (60).
Aspirin: The cytotoxic effects of curcumin increased significantly in the presence of aspirin (60).