Tokyo, Aug 10 (IANS): Eating carrots, onions and broccoli are passe, the humble radish could be the newest heart-healthy vegetable, say researchers.

The findings showed that compounds found in the Sakurajima Daikon, or "monster," radish could help protect coronary blood vessels and potentially prevent heart disease and stroke, researchers including Katsuko Kajiya from the Kagoshima University in Japan said.

Grown for centuries in Japan, the Sakurajima Daikon is one of the Earth's most massive vegetables. In 2003, the Guinness Book of World Records certified a Sakurajima weighing nearly 69 pounds as the world's heaviest radish.

Radishes are good sources of antioxidants and reportedly can reduce high blood pressure and the threat of clots, a pair of risk factors for heart attack and stroke.

But to date, no studies have directly compared the heart-health benefits of the Sakurajima Daikon to other radishes.

The study, appearing in the Journal of Agricultural and Food Chemistry, could lead to the discovery of similar substances in other vegetables and perhaps lead to new drug treatments, the researchers said.

Kajiya's team exposed human and pig vascular endothelial cells to extracts from Sakurajima Daikon and smaller radishes.

Using fluorescence microscopy and other analytical techniques, the team found that the Sakurajima Daikon radish induced more nitric oxide production in these vascular cells than a smaller Japanese radish.

Nitric oxide is a key regulator of coronary blood vessel function.

They also identified trigonelline -- a plant hormone -- as the active component in Sakurajima Daikon that appears to promote a cascade of changes in coronary blood vessels resulting in improved nitric oxide production.