Folk medicines traditionally used to lower blood pressure based on lavender, fennel, and chamomile among herbs discovered to act upon a shared therapeutic target in blood vessels. In a UC Irvine study, the team explain the molecular mechanisms that make them work.
Documented use of botanical folk medicines stretches back as far as recorded human history. There is DNA evidence, dating back 48,000 years, that suggests the consumption of plants for medicinal use by Homo neanderthalensis. Archaeological evidence, dating back 800,000 years, even suggests non-food usage of plants by Homo erectus or similar species. Today, evidence of the efficacy of botanical folk medicines ranges from anecdotal to clinical trials, however the underlying molecular mechanisms often remain elusive.
Published in the Proceedings of the National Academy of Sciences (PNAS), the study illustrates how many of the known traditional botanical plants used to lower blood pressure activate a specific potassium channel (KCNQ5) in blood vessels. KCNQ5, combined with other potassium channels including KCNQ1 and KCNQ4, is expressed in vascular smooth muscle. When activated, KCNQ5 relaxes blood vessels, making it a logical mechanism for at least part of the hypotensive actions of certain botanical folk medicines.
Interestingly, UC Irvine reported in its press release that the KCNQ5-selective potassium channel activation feature found in the botanicals is lacking in the modern synthetic pharmacopeia. Until now, it seems to have eluded conventional screening methods utilizing chemical libraries, which may account for why it is not a recognized feature of synthetic blood pressure medications.
The study was supported by the National institutes of Health, National Institutes of General Medical Sciences and the National Institute of Neurological Disorders and Stroke. Also involved in the study were UCI’s Rian Manville, PhD, PhD student Kaitlyn Redford and Benjamin Katz, PhD and from the University of Copenhagen, Denmark, PhD student Jennifer van der Horst and Thomas Jepps, PhD.
Geoff Abbott, PhD, professor of Physiology and biophysics, UCI School of Medicine