People have practiced traditional or folk medicine — which the Western world generally considers alternative medicine — for centuries, and it remains the mainstay of healthcare in many countries.
Much traditional medicine relies on the use of plants, which have been the basis of medical treatments for thousands of years. Sometimes, researchers examine this traditional knowledge, interpret it in modern scientific terms, and then translate it into Western medicine.
Aspirin, for example, comes from willow plants and has played a role in medicine since ancient Egyptian times, long before people understood its mechanism of action.
A new study from the University of California, Irvine School of Medicine shows a similar story for capers, which people around the world consume and also use in traditional medicine.
The study, which appears in Communications Biology, finds that a compound in pickled capers activates potassium channels that regulate the activity of the heart and brain.
The researchers say that their findings could aid the design of new drugs for epilepsy and arrhythmia (abnormal heart rhythms).
The authors of the study note that humans have been eating capers for more than 10,000 years. Findings in soil deposits in Syria and late Stone Age cave dwellings in modern day Greece and Israel have shown this to be true.
The ancient Roman cookbook “Apicius” also mentions capers. People continue to use them in traditional medicine for their antihelminthic, anticancer, antidiabetic, and anti-inflammatory properties and their possible circulatory and gastrointestinal benefits.
The research team behind the current study has now shown how capers act on the body, which includes activating a potassium channel important for heart and brain activity.
The researchers started looking at capers based on the results from a screen of plant extracts. They screened a range of extracts for activity on a family of potassium channels called KCNQ channels.
The KCNQ family of potassium channels plays several important roles in the body, including regulating the heartbeat, the contraction of muscles, and the function of the gastrointestinal tract. Their dysfunction is associated with certain diseases, including diabetes, arrhythmia, and epilepsy.
The researchers used an extract from pickled capers, the most common form in the United States, and found that a 1% extract was able to activate the channels.
The pickling process causes the formation of quercetin, which is the compound that activates KCNQ channels.
Further experiments with quercetin found that it binds to a part of the channels responsible for sensing electrical activity. This binding causes the channels to open when they would otherwise be closed, which may underlie the medicinal properties of capers.
Although capers are the richest natural source of quercetin, the authors note that other plant-derived compounds, such as E-2-dodecenal (present in cilantro), are more potent activators of KCNQ channels.
However, the authors also found that these compounds can work together. So, while eating capers alone may not have a significant effect, eating them together with other specific foods, such as cilantro, could increase their benefits.
Quercetin is also very common in food, being present in apples, berries, celery, chili peppers, and onions, as well as green tea and red wine. The compound may, therefore, accumulate in the body over time to provide benefits. Research has also shown that adding quercetin to food is safe, although this practice does not currently exist in the U.S.
Outside of food, the researchers say that their findings could help medicinal chemists design new drugs.
“Increasing the activity of KCNQ channels in different parts of the body is potentially highly beneficial. Synthetic drugs that do this have been used to treat epilepsy and show promise in preventing abnormal heart rhythms.”
– corresponding author Geoffrey Abbott, Ph.D.
Researchers are also investigating capers for their potential benefits against cancer, diabetes, and various inflammatory, circulatory, and gastrointestinal diseases. Understanding how capers act on the body on a molecular level could, therefore, lead to a wide range of new treatments.
