Scientists from UC Irvine found compounds in both green and black tea relax blood vessels by activating ion channel proteins in the blood vessel wall.
The finding helps explain tea’s antihypertensive properties and could lead to the design of new blood pressure-lowering drugs.
The research is published in Cellular Physiology and Biochemistry and was conducted by ….. et al.
As many as one-third of the world’s adult population has high blood pressure, and this condition is considered to be the number one modifiable risk factor for global cardiovascular disease and premature mortality.
New approaches to treating hypertension have enormous potential to improve global public health.
In the study, the team found that two catechin-type flavonoid compounds (epicatechin gallate and epigallocatechin-3-gallate) in tea, each activate a specific type of ion channel protein named KCNQ5, which allows potassium ions to diffuse out of cells to reduce cellular excitability.
As KCNQ5 is found in the smooth muscle that lines blood vessels, its activation by tea catechins was also predicted to relax blood vessels.
Prior studies found that drinking green or black tea can reduce blood pressure by a small but consistent amount, and catechins were previously found to contribute to this property.
Identification of KCNQ5 as a novel target for the hypertensive properties of tea catechins may facilitate medicinal chemistry optimization for improved potency or efficacy.
In addition to its role in controlling vascular tone, KCNQ5 is expressed in various parts of the brain, where it regulates electrical activity and signaling between neurons.
Pathogenic KCNQ5 gene variants exist that impair its channel function and in doing so cause epileptic encephalopathy, a developmental disorder that is severely debilitating and causes frequent seizures.
Because catechins can cross the blood-brain barrier, the discovery of their ability to activate KCNQ5 may suggest a future mechanism to fix broken KCNQ5 channels to ameliorate brain excitability disorders stemming from their dysfunction.
The team also found the addition of milk prevented the beneficial KCNQ5-activating effects of tea.
But they don’t believe this means one needs to avoid milk when drinking tea to take advantage of the beneficial properties of tea.
They suggest that the environment in the human stomach will separate the catechins from the proteins and other molecules in milk that would otherwise block catechins’ beneficial effects.
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If you care about tea, please read studies that green tea can boost your immune function, and green tea may protect your body as a vaccine.
For more information about blood pressure, please see recent studies that blood pressure swings could be an early sign of heart disease, and results showing beetroot may protect against high blood pressure.
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