The compound, an epicatechin polyphenol, is found in bitter English apples that were originally grown hundreds of years ago but are now no longer eaten.
Trials have revealed that epicatechin can help maintain a healthy circulation by relaxing arteries and increasing blood flow.
The research was conducted independently by the Institute of Food Research in Norwich.
It shows it can dramatically reduce arterial stiffness by 21 per cent, which in turn leads to lower blood pressure and a reduced risk of heart disease and stroke, reports the Daily Express.
In the study, volunteers who were given the ingredient mixed in with fruit juice also saw their vascular age - the apparent age of a person's blood vessels rather than their real age - reduced by an average of 17 years.
British firm Coressence has now developed a strain of red-fleshed apples called Evesse that are rich in epicatechin.
The company tested many varieties but found that older, bitter strains contained far more epicatechin than the sweet modern ones sold in supermarkets.
The Evesse variety, which has its root in a hawthorn apple dating back to 1650, is being grown on 100 acres of orchards in Herefordshire.
Nutrition expert Dr Carrie Ruxton said: "The research on Evesse is tremendously exciting. The fact that it is easily incorporated into ordinary foods means that it has the potential to benefit many people."