The Sakurajima radish dwarfs the regular radishes pictured here.
The official name for the so-called monster radish is the Sakurajima daikon.
Originally cultivated on the island of Sakurajima, Japan, centuries ago, it is an impressive beast.
The largest Sakurajima on record weighed almost 69 pounds, measuring well over 1 meter in circumference.
Radishes in general are known to contain high levels of antioxidants. Also, according to earlier studies, they may influence factors associated with heart attack and stroke — namely, increased blood pressure and the risk of blood clots.
Roughly 1 in 4 deaths are due to cardiovascular diseases, such as heart attack and stroke, so discovering a natural chemical that can reduce the risks would be a big win.
Dissecting the monster radish
To date, no studies have investigated the potential cardiovascular benefits of the monster radish. So, recently, researchers from Kagoshima University in Japan set up a trial to see whether the radishes' health benefits are as sizable as its girth. The results were published recently in the Journal of Agricultural and Food Chemistry.
The team of scientists, led by Katsuko Kajiya, was particularly interested in the Sakurajima's influence over nitric oxide production, an important regulator of blood vessel function.
The cells that line blood vessels — vascular endothelial cells — produce nitric oxide; when this gas is released into the bloodstream, it causes blood vessels to relax, which reduces blood pressure.
Nitric oxide helps reduce cardiovascular risk in more than one way: white and red blood cells sometimes attach to blood vessel walls, which increases the risk of clots forming. Nitric oxide release prevents this from happening so freely.
Antioxidants are thought to damage endothelial cells, which reduces their ability to produce nitric oxide and therefore increases the risk of cardiovascular disease.
Uncovering interventions that can induce nitric oxide release from these cells would, therefore, have a protective effect on vascular health.
The team used vascular endothelial cells from both humans and pigs to pit Sakurajima daikon against other, less impressive types of radish. Using a range of tests, including fluorescence microscopy, the scientists demonstrated that the monster radish "induced more nitric oxide production" than its diminutive cousins.
Radish compound identified
Kajiya also wanted to understand exactly how the Sakurajima daikon influences nitric oxide. After ruling out other potential compounds, including the neurotransmitter GABA, the team concluded that a plant hormone called trigonelline could be the main player.
Trigonelline seems to trigger a molecular cascade that boosts nitric oxide production. Interestingly, trigonelline is not a stranger to medical research, as the authors explain:
"The compound is found in coffee and some agricultural and marine products. [...] Trigonelline has been reported to reduce brain aging and Alzheimer-type dementias, and it has inhibitory effects on the invasion of cancer cells."
The compound may also be useful in the prevention of diabetes. It is present in a number of plants, including garden peas, hemp seed, oats, and potatoes. It might be that, over the coming years, we hear more about the potential uses of this chemical.
The authors of the new study hope that their results will be useful to scientists looking for active components in other vegetables.
Once the mechanism is understood in more detail, it could lead to much improved pharmaceutical interventions that slow the progression of cardiovascular disease or prevent it from developing in the first place.