How Do Herbs and Medicinal Plants Lower Blood Pressure?

We all know that regular exercise and diets low in saturated fats reduce arterial plaques and improve overall cardiovascular health. We're more likely to substitute lower-fat foods for rich, high-cholesterol dishes if they're elegantly seasoned and prepared, but can herbs and other plant-based foods — outside of their culinary functions — directly prevent hypertension?

Understanding High Blood Pressure

The American Heart Association defines hypertension (high blood pressure) as the consistently-elevated force of blood pushing against the walls of your blood vessels. When blood pressure is too high, it overworks your heart and arteries. Damage to the circulatory system makes it easier for cholesterol plaques to stick to arterial walls, both hardening and narrowing them. This buildup is called atherosclerosis, and it prevents your organs and tissues from receiving nutrients and oxygen. High blood pressure contributes to heart attacks and strokes. 

Blood vessel walls have special muscles that constrict and relax to help regulate blood flow in response to body temperature, physical activity, and stress. Vasoconstriction, if you haven't guessed, increases blood pressure while vasodilation allows it to pass more freely.

Now that we've got Hypertension 101 out of the way, let's take a look at how medicinal plants can fight heart disease. 

Hypertension-Reducing Compounds in Medicinal Plants

Here are some quick-and-dirty facts about some of the major plant-based compounds that promote cardiovascular health. We're breaking things down to Barney-level basics since we skated through chemistry class. 

Flavonoids

This large family of plant-based micronutrients has earned its stripes fighting all sorts of diseases in humans, including diabetes, cancer, neurological disorders, and cardiovascular problems. Of the six major flavonoid types, anthocyanins or flavan-3-ols (yes, that's a thing) are the chemicals believed to play the largest role in maintaining vascular health, specifically aiding blood vessel linings (vascular endothelium) in repelling plaque buildups and maintaining the ability to constrict and relax. Flavonoids are effective at fighting cell-damaging free-radicals. 

Nitric oxide 

Our vascular endothelium generates the nitric oxide molecule (NO), but we can also source nitric oxide from our diets. Nitric oxide triggers enzymes that cause vasodilation. 

Caffeic acid

Present in almost all plants, caffeic acid is an anti-inflammatory and antioxidant. 

Omega-3 fatty acids

You might think of salmon as being the primary source of omega-3 fatty acids, but it's present in vegetable matter as well. According to The Mayo Clinic, Omega-3 fatty acids may benefit heart health by:

• Decreasing triglycerides
• Lowering blood pressure slightly
• Reducing blood clotting
• Decreasing your risk of strokes and heart failure risk
• Reducing irregular heartbeats

Eugenol

Eugenol is a naturally-occurring anti-inflammatory and anti-pain compound. Eugenol is a primary active ingredient in dental pain treatments, but in high concentrations administered in high dosages may be toxic. Eugenol is believed to be a calcium channel blocker, reducing calcification in vessels. 

Terpenes

Terpenes contribute to a plant's resin, oils, and pungent aroma. Thank terpenes for their anti-inflammatory, anti-viral, and pain-relieving (analgesic) properties. Terpene compounds also reduce anxiety, but their direct influence on cardio function is still up for scientific debate. We're leaving this here anyway. 

These Herbs and Plants May Lower Blood Pressure

We've selected a few plants that have become popular in Western cultures for their marketed potential to improve cardiovascular health, highlighting their active compounds and, when available, relevant and recent scientific research. There are a lot of contradictory studies out there, so consider this list and its contents as a jumping-off point for your own research.

Bay leaf/Cinnamon (Cinnamomum tamala)

There are several types of bay leaf plants, but C. tamala is used for both its aromatic leaves and its bark — what we know as cinnamon. Bay leaf is an essential Ayurvedic herb and is rich in eugenol and Vitamin A. It's also flush with potassium, important for moderating blood pressure and heart rate. 

Clove (Syzygium aromaticum)

Clove oil contains up to 95% eugenol, and it's rich in flavonoids. The eugenol used in dental medicine was sourced from clove oil for the purpose of easing inflammation and pain. 

Flax (Linum usitatissimum)

There's a lot of hype associated with flaxseed oil and its benefits to heart health, with some studies claiming it's the end-all, be-all natural solution to hypertension while others warn that, at best, flax is a possible supplement to conventional blood pressure treatments.  

We do know that flax is high in Omega-3 fatty acids, but its alpha linolenic acid and lignan content may be the reason flaxseed is a good candidate for a more focused study using concentrated flaxseed oils. 

Garlic (Allium sativum)

A few decades ago, garlic stepped up as the gateway drug in the mainstream zeitgeist of plant-based medicine. Since then, numerous legitimate studies have backed up claims that garlic is effective in heart health, particularly reducing hypertension, fat levels in the blood, and plaque buildup. Garlic's most notable compounds are allicin and nitric oxide. According to research, allicin is believed to act as a vasodilator and a preventative for blood clots. Most research indicates that garlic is most effective as an aged extract.

Ginger (Zingiber officinale)

This rhizome's active compounds, [6]-shogaol, and [6]‐Gingerol, may help reduce vasoconstriction. Traditional medicine promotes ginger's antioxidizing compounds as beneficial to reducing cholesterol and the risk of blood clots. 

Green tea (Camellia sinensis)

High in flavonoids, specifically catechins and epicatechins, green tea is believed to reduce plaque buildup and help vessels regulate blood flow during times of stress. It may even lower harmful LDL cholesterol levels, according to Harvard Health Publishing. Black tea, to a lesser extent, shares these benefits. A couple of cups of green tea a day are considered safe, according to Dr. Howard Sesso, associate professor of medicine at Harvard Medical School and associate epidemiologist at Brigham and Women's Hospital, but he warns against using concentrated formulas due to the potential risk of kidney stones caused by oxalates. And take it straight; adding sugar to green tea cancels out its benefits. 

Hawthorn (Crataegus oxyacantha) 

A staple herb in Chinese medicine, flavonoid-rich hawthorn is believed to serve as a vasodilator and may reduce diastolic blood pressure and hardening of the arteries. 

Motherwort (Leonurus cardiaca)

The specific name, cardiaca, bodes well for this plant's place in contemporary herbal medicine. In the past few decades, studies on motherwort's notable compounds, including ursolic acid and the alkoloid stachydrine, respectively fight free radicals and reduce systolic and diastolic blood pressure. Motherwort's also known to reduce anxiety and ease insomnia. 

Pansy (Viola tricolor)

Also called "heartsease" for its long history as a traditional medicinal herb, pansy is believed to be a rich source of antioxidants and flavonoids. Herbalists claim pansy essential oil helps soothe depression, anxiety, and even "broken hearts." It's up to you to decide if the latter benefit qualifies as improving heart health.

Rose (Rosa)

The aromatherapeutic use of rose oil appears to lower systolic blood pressure and increase blood flow. Rose oil is heavy in terpenes and flavonoids, and fresh rose hips (not dried) contain a ton of anti-oxidizing Vitamin C, but the jury's still out on findings that high doses of Vitamin C have a beneficial effect on hypertension. 

Sweet basil (Ocimum basilicum) and Holy basil (Ocimum sanctum)

Basil is loaded with eugenol, Omega-3, antioxidants, and other vitamins and minerals essential to circulatory health. Basil extract is known to temporarily lower blood pressure, but its compounds may have longer-lasting, heart-protective effects. Holy basil, also known as "tulsi," is an Ayurvedic herb with a higher eugenol content than its cousin. 

A Lesson Learned from Chamomile, Fennel, and Lavender

All three of these herbs have gained notice in a study at the University of California, Irvine for their ability to open up pathways for potassium in vascular smooth tissue, helping the vasodilation process. The plants' superpowers exist on a molecular level, rather than in a compound or essential oil. The authors wrote:

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.

The study tips its hat to herbal folklore's long (we're talking 800,000+ years) history, and unintentionally reminds us that sometimes "stuff just works" and we haven't gotten around to figuring out exactly why. Who knows what we'll learn about these traditional medicinal plants in the future?

Growing Your Own Heart-Healthy Plants is the Best Medicine

Just because something is rich in hypertension-reducing compounds doesn't mean it's right for you, or that you'll be able to consume enough of the plant to reap the rewards. We wanted so badly to add red wine to the list (we'd have been going out on a limb anyway) but the alcohol cancels out all but the psychological benefits. 

The best natural heart medicine is exercise and a balanced diet. When you have fresh, high-quality seasonings and produce on hand, you're more likely to prepare healthy snacks and meals — especially if you grow them at home. According to The American Institute of Stress, gardening provides physical activity, sunlight-produced Vitamin D, and mental focus that helps improve heart health. They also claim that 45 minutes spent gardening can significantly reduce the "stress hormone" cortisol, which contributes to hypertension. 

Seed Needs won't try and take your prime rib and roast pork away from you but we can help you grow your own vegetables and herbs from seed. How you use them is up to you and your doctor. We're happy to share what we know about plants and their potential medicinal properties, but we encourage you to do your own objective research and consult with medical professionals, including your pharmacist. 

As for other matters of the heart? If you don't have room for a garden at home, seek out and support a local community garden. Socializing reduces hypertension, and given what we know about our customers, gardeners make wonderful friends.