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The science behind folk remedies

October 22, 2019 | UCI Health
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Lavender, basil, chamomile and fennel all have a venerable tradition as folk remedies to lower blood pressure. Cilantro has long been said to be an anti-convulsant for people with epilepsy.

UCI School of Medicine researchers have now discovered how these herbs work at the molecular level, opening a path to develop natural products to treat these conditions and perhaps others.

“We’re doing the hard science to understand how botanical medicines work,” says Geoffrey Abbott, PhD, a professor in the medical school’s Department of Physiology and Biophysics, whose lab is leading the research effort.

“It’s really satisfying to be able to look at plants used by ancient civilizations and say that we now partially understand how they work.”

How do herbs lower blood pressure?

The scientists tested 10 different herbs known to lower blood pressure to see if they activated the KCNQ5 gene, which is a potassium channel expressed in the smooth muscles surrounding blood vessels.

All the herbs — lavender, basil, chamomile, fennel seed, thyme, oregano, marjoram, ginger, Vietnamese Sophora root and Sophora flavescens root — activated KCNQ5, which relaxed the muscles and allowed the same amount of blood to flow through the vessels but at a lower pressure.

“From our results, we can say fairly conclusively that activation of KCNQ5 is at least part of the mechanism that works to lower blood pressure in all 10 of the hypotensive plant extracts we tested,” Abbott says. “We were pretty stunned by our findings.”

Lavender, fennel seed extract and chamomile were the most effective KCNQ5 potassium channel activators.

“It’s a new way of thinking about lowering blood pressure,” he says. “But in a way it’s an old way, because people have been using them for millennia, without knowing how they worked.”

How does cilantro reduce seizures?

Folk medicine and modern medicine have found a range of benefits from cilantro, from reducing pain and inflammation to protecting against skin cancer. It also has been used throughout Central America, the Caribbean and other cultures for hundreds of years to reduce seizures in epileptics.

As it turns out, disruption of KNCQ2 and KCNQ3 channels can cause seizures. The UCI team thought cilantro might work the same way as the herbs did to open the KCNQ5 potassium channel. It turns out, they were right — it opens the brain channels and eases seizures.

“We found that one of the compounds in cilantro is a highly potent KCNQ channel activator, and discovered the molecular basis for the anticonvulsive effect of cilantro,” Abbott explained.

Will these herbs replace drugs?

While Abbott sees a great potential for these herbs to help lower blood pressure, ease seizures and help with a variety of other conditions, he cautions that people shouldn’t stop taking any medications prescribed for these conditions.

There may be value — and little harm — from consuming herbs, although this might only lower blood pressure by a few points, he says.

But if you want to take any of the various so-called nutraceuticals — or herbal supplements — that are currently sold online and in health food stores, he recommends doing careful research first since most of these don’t require FDA approval or the testing for safety and efficacy that drugs do.

“Look at how trusted the source is, the safety procedures used, whether the producer is certified,” Abbott says. “Just because they’re natural, it doesn’t mean they’re safe.”

Back to the future

Abbott believes the future for developing nutraceutical compounds and drugs based on these research findings is bright. But that will come only after much more research is conducted. Going forward, he wants to do more studies on the efficacy of these herbs on the whole person.

His interest in plants as medicine began after one of his post-doctoral trainees, Rian W. Manville, discovered a component in an African shrub that activated the KCNQ2/3 potassium channel. But it didn’t help with seizures. Further testing revealed that two compounds in the plant were needed — and when they were added together, they synergized more effectively to open the KCNQ2/3 channels and prevent seizures. 

The researchers then became interested and discovering whether herbs more commonly used in the United States worked in similar ways. They started gathering herbs from local supermarkets and analyzing them, which ultimately led to these important discoveries.

Abbott says they now are studying roughly 3,000 plants used for traditional Native American medicine and are currently taking field trips to various national parks, where Abbott holds research permits to collect plants for scientific analysis.

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