A latin American seed once used by Mayans as body paint and today as an orange food coloring in your cheddar cheese may prove useful in the fight against skin cancer. Scientists have found that a compound found in natural food additive annatto prevents the formation of cancer cells resulting from UV radiation in mice, and are now exploring whether annatto-rich diets can prevent similar sun damage in humans.

Derived from the achiote tree, annatto has been a source of lipstick, body makeup, and cooking ingredients for native Americans since the pre-Columbian era. Now it is used as a common food additive for things like cheese, butter and margarine.

Scientists working at the University of Arizona College of Pharmacy have now discovered that it may also have a role to play in tackling skin cancer. Associate professor Georg Wondrak hunts for small molecules that can prevent the cancer by activating the Nrf2 pathway, which strengthens the body's cells against exposure to carcinogens.

When he happened upon a compound in annatto called bixin that appeared to do just that, he conducted an experiment on mice to further investigate its cancer-preventing properties. One group of mice that was injected with bixin and another group that was not were both exposed to UV radiation, with those receiving the dosage experiencing much less severe damage to their skin.

Wondrak says the compound works by inducing cells to produce protective antioxidants and repair factors, meaning it prevents the forming of skin cancer cells rather than attacking them after the fact.

The team are now seeking to explore if it has the same effect in humans. Conveniently, the fact that annatto is already approved by the Food and Drug Administration as a safe food additive means there'll be less hoops to jump through as they work toward clinical trials.

The research was published in the journal Free Radical Biology and Medicine.