Feature Article: June 2025 – Natural Strategies for Managing Hypertension

Elizabeth Sutherland, N.D. and Michael Friedman, N.D.

Hypertension in the U.S.: Significance and Underlying Risk Factors

Uncontrolled, chronically high blood pressure (hypertension) contributes to a host of complications known collectively as hypertensive heart disease (HHD).¹ HHD accounts for approximately 10 million deaths annually and is, therefore, a serious global public health issue.² Nonmodifiable risk factors for high blood pressure include age, genetic predisposition, ethnicity, and some comorbid conditions, such as diabetes or kidney disease,^3,4 which may themselves be affected by modifiable contributory factors. High blood pressure is also influenced by several modifiable factors such as being overweight, poor diet, excessive salt intake, smoking, high alcohol intake, and lack of physical exercise. In fact, hypertension is considered to be the leading modifiable risk factor for cardiovascular disease and premature death worldwide.⁵ The majority of patients with heart failure, which can be acute or chronic,⁶ have a history of hypertension.⁷ 

The Role of Hypertension in Heart Failure

The mechanisms by which hypertension influences the development of heart failure are not completely understood, but they may differ between heart failure with reduced ejection fraction(systolic) and heart failure with preserved ejection fraction (diastolic). Systolic heart failure means the heart does not optimally contract during each heartbeat, whereas diastolic heart failure refers to the heart’s inability to optimally relax between beats.⁸ Over time, increased hemodynamic stress on the heart from high blood pressure leads to the compensatory development of left ventricular hypertrophy (LVH). 

Medical understanding of heart failure centers on this model of chronically elevated blood pressure leading to LVH and diastolic dysfunction, which cause myocardial rigidity to the extent that the myocardium can no longer effectively function in response to changes in preload, afterload, and sympathetic tone. Emerging evidence, however, suggests that heart failure with preserved ejection fraction, which is characterized by abnormalities in the relationship between diastolic pressure and volume, may be due to systemic proinflammatory changes that are secondary to certain comorbid conditions, including hypertension. Signs and symptoms of heart failure with preserved ejection fraction can overlap with those of systolic heart failure, but diastolic heart failure is a more heterogeneous condition. 

Addressing systemic hypertension, therefore, is key to managing both types of heart failure, but pharmacologic treatments used for systolic heart failure are not as successful in the treatment of diastolic heart failure and have not shown definitive benefit against mortality.⁹ Several non-pharmacological and lifestyle approaches may offer considerable support in the management of high blood pressure. One such botanical ally is Rauwolfia.

Clinical Applications of Rauwolfia as an Anti-Hypertensive

Before pharmaceutical drugs such as beta blockers, calcium channel blockers, and angiotensin-converting enzyme (ACE) inhibitors were available, a natural substance known as reserpine was widely used to manage hypertension. Reserpine is a bioactive indole alkaloid derived from the plants Rauwolfia serpentina (Indian snake root) and Rauwolfia vomitoria (African snake root). In India, Rauwolfia serpentina has a documented history spanning 3000 years of medicinal use for a variety of ailments.¹⁰ Traditionally, Rauwolfia was also used as a calming agent, likely for people exhibiting signs of what we now know to be high blood pressure and arrhythmias. In more modern times, scientific research on the anti-hypertensive properties of Rauwolfia began in the 1930s and 1940s. Serpasil, a Rauwolfia-based medicine for hypertension, was released in the United States in the 1950s.¹¹ The use of isolated alkaloid preparations fell out of favor as other antihypertensive pharmaceuticals became available, but several medications for hypertension derived from reserpine are still used in other parts of the world today. 

In recent years, Rauwolfia vomitoria has been studied for its therapeutic effects, as an alternative to Rauwolfia serpentina, which is an endangered species that it is now illegal to export. Rauwolfia vomitoria grows in Africa, mainly in Cameroon, Senegal and Egypt. Every part of Rauwolfia vomitoria is rich in indole alkaloids, but the root bark contains the highest concentration, and is used both as a sedative, and to treat hypertension.^12,13 In addition, Rauwolfia vomitoria has been found to have hypoglycemic properties,¹⁴ and the leaf extract was shown to reduce cholesterol levels in animal models.¹⁵ Both of these effects may be helpful to attenuate certain modifiable risk factors for hypertension, such as diabetes and being overweight. They also underscore the importance of using whole-plant extracts, as the whole plant contains β-sitosterol, which inhibits cholesterol absorption.¹⁶

Rauwolfia and High Blood Pressure: Mechanisms of Action

Rauwolfia’s effects on the heart include decreasing myocardial excitability, inhibiting atrial-ventricular conduction, and prolonging the refractory period of the heart rhythm.¹⁷ While many therapeutic effects of Rauwolfia serpentina and Rauwolfia vomitoria have been attributed to the hypotensive indole alkaloid reserpine,¹⁸ more than 50 indole alkaloids have so far been identified in Rauwolfia roots including ajmaline, ajmalicine, hydroxysarpagine, imethylajmaline, isorauhimbinic acid, methylisoajmaline, raubasine, and yohimbinic acid. The hypotensive and antiarrhythmic effects of Rauwolfia are likely mediated by reserpine, ajmaline, and ajmalicine.^19,20

The indole alkaloid, reserpine, appears to act as an adrenergic blocking agent via its binding affinity with the vesicular monoamine transporters (VMATs) system that regulates norepinephrine vesicular storage. Reserpine binds to and inhibits the pumping of catecholamine storage vesicles in both central and peripheral adrenergic neurons. This results in the decreased uptake of norepinephrine, dopamine, and serotonin, which control heart rate, cardiac contraction, and peripheral resistance from presynaptic storage vesicles.²¹ Depleting releasable stores of catecholamines from storage vesicles, therefore, decreases sympathetic activity, which lowers heart rate and dilates arterial blood vessels, thereby producing both hypotensive and parasympathetic, calming effects.^22,23,24

Cellular calcium influx and transport mechanisms that result in vascular smooth muscle constriction are also implicated in the pathogenesis and clinical course of hypertension. Research suggests that Rauwolfia interacts with vascular baroreceptors to elicit vascular relaxation and reduce peripheral resistance, thereby improving blood pressure and oxygen saturation of the tissues.²⁵ 

Clinical Evidence of Rauwolfia Efficacy

In recent years, only a few small randomized controlled trials have examined the use of reserpine or Rauwolfia for hypertension, but the results have been promising and corroborate decade’s worth of clinical observation.²⁶ A Cochrane meta-analysis concluded that Rauwolfia displayed similar efficacy to first-line antihypertensive drugs, without significant side effects.²⁷ A study of 108 elderly patients with II stage hypertensive disease found that reserpine decreased arterial pressure and peripheral vascular resistance while increasing oxygen saturation in the tissues.²⁸ In another study, a Rauwolfia product was given to more than 100 patients with essential hypertension for periods of one month to one year. The product was well tolerated, and had a moderate hypotensive effect, particularly in patients with unstable hypertension and tachycardia, but did not cause postural hypotension.²⁹

Important Takeaways 

It is important to note that most Rauwolfia studies were conducted using isolated preparations of a single indole alkaloid constituent, reserpine, rather than extracts of the whole plant. This has given rise to a great deal of misinformation regarding the safety profile of Rauwolfia, as concerns about adverse effects that may have been observed with the reserpine isolate have been extrapolated, without any basis in evidence, to Rauwolfia, the whole plant. Unlike isolates of single extracts, which may have a greater potential to lead to negative effects, whole plant extracts generally act in balanced and synergistic ways. Furthermore, even the idea that reserpine may lead to depression by depleting dopamine from dopaminergic neurons turns out to be speculative. In fact, a systematic review found that both reserpine and Rauwolfia are associated with improvements in depression.³⁰ Another serious misconception about Rauwolfia is that it is hepatotoxic. However, in an animal model of liver toxicity, Rauwolfia vomitoria was actually shown to be hepatoprotective.³¹

The usual starting dose for Rauwolfia is about 10-25 mg of crude herb (which typically contains around 125 mcg of reserpine) once or twice a day. Based on extensive traditional use and current use in clinical practice, the main side effect to be on the lookout for with Rauwolfia in the therapeutic range is hypotension, which can be used as a gauge for monitoring dosage of this powerful plant ally in the management of high blood pressure. 

References

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BIOS:

Dr. Michaël Friedman

Naturopathic physician Dr. Michaël Friedman is author of the recent book There’s No Pill for This: A Naturopathic Physician’s Personal Prescription for Managing Multiple Sclerosis (Chelsea Green, 2020). He is the founder of the Association for the Advancement of Restorative Medicine and the Journal of Restorative Medicine. He also creates and formulates herbal and nutritional supplements, and is cofounder and president of the Restorative Formulations supplement company. He is the author of the medical textbook Fundamentals of Naturopathic Endocrinology, a contributing author of Evidence-Based Approach to Restoring Thyroid Health, and co-author of Healing Diabetes. He has treated patients with illnesses ranging from lymphoma to liver cancer, achieving remarkable results that have been published in several medical journals.

Dr. Elizabeth Sutherland

Dr. Elizabeth (Liz) Sutherland began her undergraduate degree at the University of Cambridge in Classics and finished it at Tufts University with a BS in Biopsychology. She earned her doctorate in naturopathic medicine (ND) from National University of Natural Medicine (NUNM), in Portland, OR, after which she completed post-doctoral research fellowships at the Kaiser Permanente Northwest (KPNW) Center for Health Research (where she subsequently became the first KPNW Research Associate to hold an ND degree) and the University of Arizona College of Medicine. She also earned a Certificate in Human Investigations for clinical trials at Oregon Health and Science University. Dr. Sutherland has served as co-investigator on a number of NIH-funded studies and is primary author or co-author on multiple peer-reviewed publications. She was Chair of the Institutional Review Board at NUNM, and also taught and redesigned the Mind-Body medicine curriculum. Currently, Dr. Sutherland serves as Vice President of Continuing Education Compliance for AARM, and editor in chief of the Journal of Restorative Medicine. In addition, she helps physicians and scientists from several wellness and medical disciplines write grant proposals, books, and manuscripts for submission to academic journals.