Olive oil contains a naturally occurring chemical that acts in a similar way to the anti-inflammatory painkiller ibuprofen, according to US scientists.

The chemical named oleocanthal by the researchers inhibits the activity of enzymes involved in inflammation in the same way as ibuprofen.

Scientists from the Monell Chemical Senses Centre in Philadelphia say the findings our significant because inflammation increasingly is believed to play a key role in a variety of chronic diseases like heart disease and cancer.

They were led to the discovery after one of the researchers noticed that fresh extra-virgin olive oil irritates the back of the throat in a similar way to ibuprofen.

"I had considerable experience swallowing and being stung in the throat by ibuprofen from previous studies on its sensory properties," said Monell biologist Gary Beauchamp.

"So when I tasted newly-pressed olive oil while attending a meeting on molecular gastronomy in Sicily, I was startled to notice that the throat sensations were virtually identical."

According to the researchers, a daily dose of 50g of olive oil is equivalent to about 10 per cent of the dose of ibuprofen recommended for adult pain relief.

The findings also explain the healthiness of a Mediterranean diet.

Dr Paul Breslin, who directed the research with Beauchamp, added: "The Mediterranean diet, of which olive oil is a central component, has long been associated with numerous health benefits, including decreased risk of stroke, heart disease, breast cancer, lung cancer, and some dementias."

The research is published in the journal Nature.