Quercetin : A compound commonly found in pickled capers can directly regulate proteins required for heartbeat, thought, muscular contraction and normal functioning of the thyroid, pancreas and gastrointestinal tract


A compound commonly found in pickled capers has been shown to activate proteins required for normal human brain and heart activity, and may even lead to future therapies for the treatment of epilepsy and abnormal heart rhythms.

Researchers from the University of California, Irvine School of Medicine have discovered that a compound named quercetin, commonly consumed when eating capers, 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.

Published in Communications Biology, the discovery was made by the laboratory of Geoffrey Abbott, Ph.D., a professor in the Department of Physiology and Biophysics at the University of California, Irvine School of Medicine. Kaitlyn Redford, a graduate student in the Abbott Lab, was first author of the study titled, “The ubiquitous flavonoid quercetin is an atypical KCNQ potassium channel activator.”

The Abbott Lab 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,” said Abbott, “future medicinal chemistry studies can be pursued to create and optimize quercetin-related small molecules for potential use as therapeutic drugs.”

The Abbott Lab 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,” said 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 traditional 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.

Cardiovascular disease has brought a great health and economic burden for society, and it has been 1 of the 10 main causes of death in the world.[1] Ischemic heart disease (ie, coronary heart disease) is a common clinical disease caused by insufficient myocardial blood and oxygen.

Restoring myocardial blood supply is the fundamental measure for treatment, and reperfusion therapy is the most effective method for clinical treatment of ischemic heart disease.

Thrombolytic agent, percutaneous coronary intervention and coronary artery bypass grafting are used for reperfusion in clinical practice.[2] Although revascularization as early as possible is the most effective way to reduce myocardial ischemic injury, it is accompanied with myocardial ischemia reperfusion injury (MIRI).

MIRI is caused by calcium overload, apoptosis, mitochondrial damage, increased generation of oxygen free radicals and other biological processes.[3]

Though the myocardial reperfusion has been improved with more timely and effective reperfusion, and more advanced percutaneous coronary intervention techniques, antiplatelet, and antithrombotic agents used to maintain the patency of infarct-related coronary arteries, there is still no effective therapy to prevent MIRI.[4]

How to effectively prevent and reduce MIRI is the focus of medical research in recent years.

Flavonoidqs are widely found in fruits, vegetables, wines, and Chinese herbal medicine. Flavonoids play an important role on antioxidative, anti-inflammatory, and antitumor.[5,6]

Quercetin is a part of natural polyphenol flavonoids in plants[7] and it is rich in Camellia sinensis.[8] Considerable quantities of quercetin were found in kale and red onions contain.[9]

Quercetin exerts multiple pharmacological effects, such as antidiabetic, antioxidative, anti-inflammatory, and antitumor.[10–12]

Epidemiological studies have shown that increasing the intake of quercetin properly can reduce the risks of certain chronic diseases such as osteoporosis, cardiovascular disease and diabetes.[13–16]

Many animal experiments have shown that quercetin has a positive effect on MIRI. In order to clarify the effectiveness and potential mechanism of quercetin for MIRI animals, we will conduct a preclinical systematic review, which is of great significance for transforming basic research into clinical treatment.


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[11]. Sinha R, Srivastava S, Joshi A, et al. In-vitro anti-proliferative and anti-oxidant activity of galangin, fisetin and quercetin: role of localization and intermolecular interaction in model membrane. Eur J Med Chem 2014;79:102–9.Cited Here |PubMed | CrossRef

[12]. Burak C, Wolffram S, Zur B, et al. Effect of alpha-linolenic acid in combination with the flavonol quercetin on markers of cardiovascular disease risk in healthy, non-obese adults: a randomized, double-blinded placebo-controlled crossover trial. Nutrition 2019;58:47–56.Cited Here

[13]. Griffiths K, Aggarwal BB, Singh RB, et al. Food antioxidants and their anti-inflammatory properties: a potential role in cardiovascular diseases and cancer prevention. Diseases 2016;4:3.Cited Here

[14]. Xing LZ, Ni HJ, Wang YL. Quercitrin attenuates osteoporosis in ovariectomized rats by regulating mitogen-activated protein kinase (MAPK) signaling pathways. Biomed Pharmacother 2017;89:1136–41.Cited Here

[15]. Eitah HE, Maklad YA, Abdelkader NF, et al. Modulating impacts of quercetin/sitagliptin combination on streptozotocin-induced diabetes mellitus in rats. Toxicol Appl Pharmacol 2019;365:30–40.Cited Here |View Full Text | PubMed | CrossRef

[16]. Shi GJ, Li Y, Cao QH, et al. In vitro and in vivo evidence that quercetin protects against diabetes and its complications: A systematic review of the literature. Biomed Pharmacother 2019;109:1085–99.Cited Here

[17]. Wong EK, Lachance CC, Page MJ, et al. Selective reporting bias in randomised controlled trials from two network meta-analyses: comparison of clinical trial registrations and their respective publications. BMJ open 2019;9:e031138.Cited Here

[18]. Henderson VC, Kimmelman J, Fergusson D, et al. Threats to validity in the design and conduct of preclinical efficacy studies: a systematic review of guidelines for in vivo animal experiments. PLoS Med 2013;10:e1001489.Cited Here |PubMed

More information: Kaitlyn E. Redford et al, The ubiquitous flavonoid quercetin is an atypical KCNQ potassium channel activator, Communications Biology (2020). DOI: 10.1038/s42003-020-1089-8


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