Curcumin

Curcumin is known for its antitumor,antioxidant, antiarthritic, anti-amyloid and anti-inflammatory properties. Anti-inflammatory properties may be due to inhibition of eicosanoid biosynthesis. In addition it may be effective in treating malaria, prevention of cervical cancer, and may interefere with the replication of the HIV virus

Curcumin acts as a free radical scavenger and antioxidant, inhibiting lipid peroxidation and oxidative DNA damage. Curcuminoids induce glutathione S-transferase and are potent inhibitors of cytochrome P450.

For the last few decades, extensive work has been done to establish the biological activities and pharmacological actions of curcumin. Its anticancer effects stem from its ability to induce apoptosis in cancer cells without cytotoxic effects on healthy cells. Curcumin can interfere with the activity of the transcription factor NF-κB, which has been linked to a number of inflammatory diseases such as cancer. Indeed, when 0.2% curcumin is added to diet given to rats or mice previously given a carcinogen, it significantly reduces colon carcinogenesis (Data from sixteen scientific articles reported in the Chemoprevention Database). A 2007 report indicates that curcumin may suppress MDM2, an oncogene involved in mechanisms of malignant tumor formation.

A 2004 UCLA-Veterans Affairs study involving genetically altered mice suggests that curcumin might inhibit the accumulation of destructive beta-amyloid in the brains of Alzheimer's disease patients and also break up existing plaques associated with the disease.
There is also circumstantial evidence that curcumin improves mental functions

Numerous studies have demonstrated that curcumin, amongst only a few other things such as high impact exercise, learning, bright light, and antidepressant usage, has a positive affect on neurogenesis in the hippocampus and concentrations of Brain-derived neurotrophic factor (BDNF), both of which reductions in are associated with stress, depression, and anxiety.

Another method to increase the bioavailability of curcumin has recently been patented that involves a simple procedure creating a complex with soy phospholipids.  At this point no supplements are available on the market in this form.