Japanese Plum Juice Concentrate Improves Cardiovascular Health

Fruit from the Japanese plum tree (Prunus mume) is a traditional food in Japan. Traditionally referred to as ‘Ume,’ the raw fruit contains toxins, and is therefore processed into juice or wine safe for consumption. Recently, bainiku-ekisu, an infused juice concentrate of Prunus mume, has attracted attention as a health promoting supplement. It has been reported that bainiku-ekisu treatment attenuates the growth-promoting signaling induced by Angiotensin II (Ang II) — a circulatory hormone that plays a central role in development of hypertension — in vascular smooth muscle cells. In a new study, scientists at Temple University explored the potential anti-hypertensive benefit of bainiku-ekisu utilizing a mouse model of hypertension with Ang II infusion.

Hypertension remains the major pre-existing pathophysiology for the development of cardiovascular diseases including myocardial infarction and stroke.

Although significant accomplishments have been made to normalize blood pressure in hypertension patients, patients still have significantly greater risk for cardiovascular disease mortality even when their blood pressure is controlled by medications.

Ang II, the major peptide hormone of the renin angiotensin system plays a central role in development of hypertension.

Inhibitors against the system are an effective and first line choice as hypertension medications. However, meta-analysis suggests that general adherence to angiotensin-converting enzyme inhibitors and angiotensin receptor blockers was only 50-60%.

“It is recognized that drugs alone are not enough to reduce the risk of cardiovascular disease in hypertension patients,” said Temple University’s Professor Satoru Eguchi.

“To help solve this problem, we became interested in a supplement that could potentially decrease cardiovascular disease risk and began investigating the effects of bainiku-ekisu, an infused juice concentrate of the Japanese plum.”

To better understand the potential anti-hypertensive effects of bainiku-ekisu, Professor Eguchi and colleagues utilized a mouse model in which animals received infusions of Ang II to induce hypertension.

Mice were then given either plain water, in the control group, or water containing bainiku-ekisu.

Evaluation of cardiovascular function and vascular tissues from both groups of mice revealed stark differences.

Most notably, mice given bainiku-ekisu did not develop hypertension, and in these animals tissue analysis indicated that the juice concentrate protected the vasculature from the effects of Ang II.

In particular, hypertrophy (growth and enlargement) of the aorta was minimal in mice given bainiku-ekisu, whereas control animals had marked aortic hypertrophy.

Bainiku-ekisu also attenuated the infiltration of immune cells, which trigger inflammatory processes associated with hypertension.

The study authors then explored possible mechanisms by which bainiku-ekisu prevented hypertension in mice.

They looked specifically at molecular pathways involved in glycolysis, the process by which cells breakdown glucose and which is a central feature of hypertension-induced hypertrophy.

“In hypertension, cells shift from aerobic metabolism to glycolysis because there is less oxygen available in the cellular environment,” Professor Eguchi said.

“This switch results in high levels of oxidative stress, which leads to more inflammation, more vascular stiffness, and, eventually, the development of more severe cardiovascular disease.”

The experiments in cells showed that bainiku-ekisu prevents the switch to glycolysis, suggesting that it protects against Ang II-induced hypertension by mitigating harmful metabolic changes that underlie hypertrophy and inflammation.

The team now plans to identify the specific compounds in bainiku-ekisu that are responsible for its protective effects.

“There may be two or three compounds working together, which could explain why the infused juice concentrate of Ume is so popular as a health supplement,” Professor Eguchi said.

“Multiple compounds working together would produce additive or synergistic effects that might be lost in a pharmaceutical preparation.”

The findings appear in the journal Hypertension Research.

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