Scientists at the University of California, Irvine (UCI), reported that they have uncovered the molecular mechanisms that help traditional herbs, including lavender, fennel, and chamomile, lower blood pressure. The team published its research (“KCNQ5 activation is a unifying molecular mechanism shared by genetically and culturally diverse botanical hypotensive folk medicines”) in 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, together 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, according to the scientists.
“Botanical folk medicines have been used throughout human history to treat common disorders such as hypertension, often with unknown underlying mechanisms. Here, we discovered that hypotensive folk medicines from a genetically diverse range of plant species each selectively activated the vascular-expressed KCNQ5 potassium channel, a feature lacking in the modern synthetic pharmacopeia, whereas nonhypotensive plant extracts did not. Analyzing constituents of the hypotensive Sophora flavescens root, we found that the quinolizidine alkaloid aloperine is a KCNQ-dependent vasorelaxant that potently and isoform-selectively activates KCNQ5 by binding near the foot of the channel voltage sensor,” the investigators wrote.
“Our findings reveal that KCNQ5-selective activation is a defining molecular mechanistic signature of genetically diverse traditional botanical hypotensives, transcending plant genus and human cultural boundaries. Discovery of botanical KCNQ5-selective potassium channel openers may enable future targeted therapies for diseases including hypertension and KCNQ5 loss-of-function encephalopathy.”
“We found KCNQ5 activation to be a unifying molecular mechanism shared by a diverse range of botanical hypotensive folk medicines. Lavandula angustifolia, commonly called lavender, was among those we studied. We discovered it to be among the most efficacious KCNQ5 potassium channel activators, along with fennel seed extract and chamomile,” said Geoff Abbott, PhD, professor of physiology and biophysics at the UCI School of Medicine and senior investigator on the study.
Interestingly, 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.
“Our discovery of these botanical KCNQ5-selective potassium channel openers may enable development of future targeted therapies for diseases including hypertension and KCNQ5 loss-of-function encephalopathy,” noted Abbott.
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.