While eating foods rich in omega-3 fatty acids, such as fatty fish, certain nuts and seeds, have been known to prevent heart diseases and arthritis, a new research, led by one of Indian-origin, showed that omega-3 fatty byproducts may also have anti-cancer effects.

The new study, led by Aditi Das from University of Illinois at Urbana-Champaign, US, showed that when the human body metabolises omega-3 fatty acids, it produces a class of molecules called endocannabinoid epoxides, or EDP-EAs. These have anti-inflammatory properties and can inhibit cancer's growth and spread.

The EDP-EAs have similar properties to cannabinoids found in marijuana -- but without the psychotropic effects -- and they target the same receptor in the body that cannabis does. "We have a built-in endocannabinoid system which is anti-inflammatory and pain-reducing. Now we see it is also anti-cancer, stopping the cells from proliferating or migrating," said study leader Aditi Das from University of Illinois at Urbana-Champaign.

"These molecules could address multiple problems: cancer, inflammation and pain," Das added. For the study, published in the Journal of Medicinal Chemistry, the team studied the effect of the molecule in mice with tumours of osteosarcoma -- a bone cancer that is not only painful but also difficult to treat.

The results showed that the endocannabinoids slowed the growth of tumours and blood vessels, inhibited the cancer cells from migrating and caused cancer cell death. The higher concentrations of EDP-EAs did kill cancer cells, but not as effectively as other chemotherapeutic drugs on the market. But, the compounds slowed tumour growth by inhibiting new blood vessels from forming to supply the tumour with nutrients. They also prevented interactions between the cells, and most significantly, they appeared to stop cancerous cells from migrating.

While dietary consumption of omega-3 fatty acids can lead to EDP-EAs, for those with cancer, something concentrated and fast acting is needed, Das said. "That's where the endocannabinoid epoxide derivatives come into play - you could make a concentrated dose of the exact compound that's most effective against the cancer. You could also mix this with other drugs such as chemotherapies," she added.