A compound common in pickled capers, quercetin, activates proteins required for normal human brain and heart activity, researchers report.

In a new study in Communications Biology, the researchers report that quercetin can directly regulate proteins required for bodily processes such as the heartbeat, thought, muscular contraction, and normal functioning of the thyroid, pancreas, and gastrointestinal tract.

They found that quercetin, a plant-derived bioflavonoid, modulates potassium ion channels in the KCNQ gene family. These channels are highly influential in human health and their dysfunction is linked to several common human diseases, including diabetes, cardiac arrhythmia, and epilepsy.

The study revealed that quercetin modulates the KCNQ channels by directly regulating how they sense electrical activity in the cell, suggesting a previously unexpected mechanism for the therapeutic properties of capers.

The mechanism may extend to other quercetin-rich foods in our diet, and quercetin-based nutritional supplements.

“Now that we understand how quercetin controls KCNQ channels,” says Geoffrey Abbott, a professor in the physiology and biophysics department at the University of California, Irvine School of Medicine, “future medicinal chemistry studies can be pursued to create and optimize quercetin-related small molecules for potential use as therapeutic drugs.”

The researchers screened plant extracts for the ability to alter activity of KCNQ channels and found that one percent extract of pickled capers activated channels important for normal human brain and heart activity. Further studies revealed the molecular mechanism—quercetin from the caper extract binds to a region of the KCNQ channel required for responding to electrical activity, and in doing so, tricks the channel into opening when it would normally be closed.

“Increasing the activity of KCNQ channels in different parts of the body is potentially highly beneficial,” says Abbott. “Synthetic drugs that do this have been used to treat epilepsy and show promise in preventing abnormal heart rhythms.”

Archaeological evidence for human caper consumption dates back as far as 10,000 years, according to archaeological findings from Mesolithic soil deposits in Syria and late Stone Age cave dwellings in the Greece and Israel.

Capers have been used as folk medicine for hundreds if not thousands of years and are in current use or study for their potential as anti-cancer, anti-diabetic, and anti-inflammatory properties, and their possible circulatory and gastrointestinal benefits.

Support for this study came from the National Institutes of Health, National Institute of General Medical Sciences, and National Institute of Neurological Disorders and Stroke.

Source: UC Irvine

Original Study DOI: 10.1038/s42003-020-1089-8