Hypertension affects up to one-third of the world’s adult population and is the leading modifiable risk factor for global cardiovascular disease and premature mortality. Novel approaches to managing hypertension have tremendous potential to boost global public health.
Antihypertensive Properties Of Tea
Both green and black tea contains compounds that relax blood vessels by stimulating ion channel proteins in the blood vessel wall, according to a recent report from the University of California, Irvine. This sheds light on tea’s antihypertensive effects and could pave the way for the creation of new blood pressure drugs.
Geoffrey Abbott, Ph.D., a professor in the Department of Physiology and Biophysics at the University of California, Irvine, made the discovery published in Cellular Physiology and Biochemistry. Moreover, a thesis titled “KCNQ5 potassium channel activation underlies vasodilation by tea” was first-authored by Kaitlyn Redford, a graduate student in the Abbott Lab.
According to the findings, two catechin-type flavonoid compounds present in tea (epicatechin gallate and epigallocatechin-3-gallate) stimulate a special type of ion channel protein known as KCNQ5, which helps potassium ions to diffuse out of cells and reduce cellular excitability. The presence of KCNQ5 in the smooth muscle that lines blood vessels helped predict that its activation by tea catechins would relax blood vessels. This was further verified by collaborators at the University of Copenhagen.
“It was found that a few catechins bind to the foot of the voltage sensor, which is the part of KCNQ5; this opens the channel in response to cellular excitation, using computer modeling and mutagenesis experiments. Due to this binding, the channel will open even more quickly and earlier during the cellular excitation process, “Abbott elaborated.
Previous research has shown that drinking green or black tea can lower blood pressure by a small but consistent amount, and catechins have been linked to this effect. The discovery of KCNQ5 as a novel target for tea catechins’ hypertensive properties could help with medicinal chemistry optimization for better potency and efficacy.
KCNQ5 is even present in different parts of the brain, where it controls electrical activity and signaling between neurons, in addition to its function of regulating vascular sound. It was found that the presence of pathogenic KCNQ5 gene variants affects the channel activity and induces epileptic encephalopathy, an extremely debilitating developmental condition characterized by recurrent seizures.
Since catechins can pass the blood-brain barrier, their capacity to stimulate KCNQ5 could point to a potential pathway for repairing damaged KCNQ5 channels and alleviating brain excitability disorders caused by them.
Tea has been developed and consumed for over 4,000 years, and about 2 billion cups of tea are consumed per day across the world, second to water in terms of the amount consumed. The three most prevalent caffeinated teas (green, oolong, and black) are all made from the leaves of the evergreen Camellia sinensis plant. The variations are resulting from varying levels of fermentation during the tea-making process.
In countries such as the United Kingdom and the United States, black tea is usually blended with milk before being drunk. When black tea was specifically added to cells containing the KCNQ5 channel, the researchers discovered that adding milk blocked the tea’s beneficial KCNQ5-activating effects.
Abbott, on the other hand, claims that “We don’t agree that this means that to reap the benefits of tea, one must drink it without milk. We are assured that the condition in the human stomach would isolate the catechins from the proteins and other molecules in milk that will otherwise prevent catechins from exerting their beneficial effects.”
Other experiments have shown that tea has antihypertensive properties independent of whether or not it is consumed with milk. Using mass spectrometry, the researchers discovered that heating green tea to 35°C changes its chemical structure, making it more efficient at activating KCNQ5.
Merely drinking tea activates its antihypertensive effects.