Hawthorn flower and cardiovascular health

James Meschino DC, MS, ROHP

Hawthorn Flower and Cardiovascular Health

There is growing acceptance of herbal medicine in the western world. Extensive international research has revealed that various plants contain specific active ingredients that can be used for health-promotion or curative purposes. Although not well publicized, 30 percent of modern conventional drugs are derived from plant sources.

Among the many botanical agents, hawthorn flower and hawthorn berries are known to contain specific bio-agents that target cardiovascular health. In fact, these effects are quite profound as they impact the bio-energetics of heart muscle and the dilation physiology of coronary arteries.

 Description 

The hawthorn tree/shrub, otherwise known as Crataegus laevigata, is native to Europe; its fruit and blossoms are used medicinally. The white flowers are strong-smelling and grow in large bunches from April to June. The fruit of the hawthorn, the berry, is known as Crataegi fructus, or Fructus oxycanthae. The berry is a wine-red to yellowish brown, wrinkled false fruit, inside of which is a brownish yellow tissue (fruit flesh) in which are embedded up to 3 hard yellow stones, or seeds.

Composition

The flowers and berries of hawthorn are rich in plant flavonoids and oligomeric proanthocyanidins.

Flavonoids:                 These components include Quercetin, quercetin-3-galactoside, hyperoside, vitexin, vitexin-4-rhamnoside, and others.

Proanthocyanidins:     These phytochemicals are special flavonoids found in darkly colored fruits and vegetables.

Carditonic amines:      These include phenylethylamine, o-methoxyphenylethylamine, tyramine and isobutylamine.

Purine derivatives:      These include adenosine, adenine, guanine and caffeic acid.

Triterpene acids:          These include ursolic, oleanolic and crataegolic acids.

Other constituents:      These include choline, acetylcholine, amygdalin, catechins and pectins.

Pharmacological Action

The main organ which hawthorn berries and flower target is the heart.

The proanthocyanidins are potent antioxidants and have proven beneficial effects, especially on stabilizing capillaries, decreasing permeability and fragility. The flavonoids in hawthorn berries can protect against the enzymatic destruction of inflammation (Biochem Pharm 1983;32:1141-1148), and prevent the release of inflammatory substances, such as prostaglandins, leukotrienes, proteases and histamine. They improve blood supply to the heart by dilating blood vessels (Planta Medica 1981;43:105-120), improve metabolic processes in the heart, increase the force of contraction, reduce rhythm disturbances, and inhibit ACE (angiotensin-converting enzyme). (Arznelmittel-Forsch 1993;43:945-949; Jpn J Pharmacol 1987;43:242-245.) Some of the flavonoids increase the force of contraction of the heart by inhibiting the enzyme cyclic AMP phosphodiesterase (Planta Medica 1981;43:183-186.)

Clinical Applications / Research

• Mild diuretic
• Heart disorders
• Congestive heart failure
• Atherosclerosis
• Angina
• High blood pressure
• Arrhythmias

A phytopharmaceutical encyclopedia lists some of the areas in which hawthorn berries are utilized: cardiotonics, coronary remedies, antihypertonics, arteriosclerosis remedies, geriatric remedies, and general tonics (Grainer, NB ed., Herbal Drugs and Phytopharmaceuticals. Medpharm Scientific Publishers. CRC Press. Boca Raton, Fla., 1994).

Hawthorn berries have a favourable effect on blood pressure (Forsch Med 1933;111:352-354; Planta Medica 1981;43:313-322.) This is probably due to the flavonoids having a stabilizing effect on collagen structures, such as the blood vessels and small capillaries, and by affecting vasodilation by the response in the prostaglandin pathway. The ability to inhibit angiotension converting enzyme (ACE) (Jpn J Pharmacol 1987;43:242-245) and to demonstrate mild diuretic activity also help reduce hypertension. The dilation of the vessels results in reduced peripheral resistance and increased coronary circulation (Hamon NW, Canad Pharm J 1988; Nov:708-724). Angiotension converting enzyme converts a relatively inactive form of angiotensin (angiotensin I) into an active, very powerful vasoconstrictor, angiotensin II. The ability of the proanthocyanidins to inhibit the converting enzyme results in relaxed blood vessels, and its action has rivaled that of the drug, Captopril (Jpn J Pharmacol 1987;43:242-245) a synthetic enzyme inhibitor used widely for hypertension.

Hawthorn berries have been traditionally used in the area of congestive heart failure, because of their ability to increase the contraction of the heart. They do this by inhibiting the enzyme cyclic AMP phosphodiesterase (Planta Medica 1981;43:183-186.) Since the enzyme breaks down the energy-boosting signaler, cyclic AMP, inhibition of the enzyme results in more forceful contractions. Hawthorn is commonly used in conjunction with other drugs for heart failure, such as digitalis, or in combination with other herbs containing cardiac glycosides (i.e., Cereus grandifloris) as it potentiates the action of the glycosides. Since hawthorn does enhance the action of the cardiac glycosides, it allows for lower doses of adjunctive therapy to be used. Magnesium also has an enhancing action  on digitalis and can be considered a good synergistic nutrient. Double-blind studies have consistently shown that hawthorn is effective for congestive heart failure in the early stages (and also minor arrhythmias) where digitalis is not yet indicated (no adverse reactions occurred in the studies.) (Forsch Med 1992; 110:290-292; Forsch Med 1986; 104:805-808; Forsch Med 1993;111:352-354.) For moderate to severe heart failure, a health care professional can recommend a combination with other cardiac glycosides.

Persistence in supplementation is recommended, as it can take up to 2 weeks to reach a satisfactory tissue saturation level. Extended use of hawthorn berries has had a beneficial effect on cholesterol, triglycerides, and blood sugar levels in Chinese animal studies (Chung His I Choeh Ho Tsa Chih 1990;10:361.)

Contra-Indications/Toxicology

Hawthorn berries are determined to have low toxicity. The average acute 50% lethal dose in rats is 25 ml per kg. And chronic dose is approximately 5 ml per kg, which is a high dose that is never achieved with standard recommendations, much less at lower levels found in synergistic combination formulas. Medicinal amounts of any herb should only be taken with the advice of a trained licensed healthcare professional.