Goldenseal for Upper Respiratory Infections
Goldenseal for Upper Respiratory Infections
May 2000; Volume 3; 56-58
By Dónal P. O’Mathúna, PhD
Goldenseal remains one of the most popular herbs sold in the United States. In the first eight months of 1999, sales of echinacea and goldenseal, often formulated together, ranked fifth among herbal remedies sold through mainstream markets.1 If your patients use herbal remedies, there’s a good chance they take goldenseal as a "natural antibiotic" to treat and prevent colds and flu.
History and Harvesting
Goldenseal (Hydrastis canadensis) is a member of the buttercup family. It is a low-growing herbaceous perennial, characterized by a bright yellow rhizome (or underground thickened stem), from which it gets its name. Other common names include golden root, eye root, and ground raspberry, because of its small red fruit. It grows naturally in the woodland areas across much of the Eastern and Midwestern United States. Overharvesting of goldenseal in the 1980s and early 1990s led to concerns that it was becoming an endangered species, especially as it was difficult to cultivate. Much progress has since been made in this area, leading to significantly expanded agricultural acreage.2
Folklore
Native American tribes (including the Cherokee, Iroquois, Crow, Seminole, and Blackfoot) commonly used this herb as a diuretic and stimulant, as a treatment for stomach ulcers, and as a wash for irritated eyes and mouth sores. It was also an important source of yellow dye. European settlers first mentioned it in 1804 as a powerful "bitter" to increase appetite and facilitate digestion, and as a mouth and eye wash.3 Goldenseal was enthusiastically promoted by the Eclectic medical doctors, who focused on herbal remedies and gave many American herbs their first scientific evaluations by carefully observing and recording their effects.3 Many Eclectics were critical of overblown claims about goldenseal, such as its alleged ability to cure cancer.
With the decline of the Eclectics in the 1930s, goldenseal’s use dropped off in the United States. Recent interest in goldenseal began when it was reported during the 1970s that oral ingestion would mask morphine in drug urinalysis. These claims have been shown to be without scientific merit, but they persist, and have broadened to include masking of marijuana and cocaine.4
Official Recommendation and Current Use
Goldenseal was officially approved as a medicinal herb in the United States Pharmacopoeia (1830-1840 and 1860-1926), and in the National Formulary (1888 and 1936-1955).3
Many pharmaceutical companies sold the root and preparations of it until the early 20th century. Goldenseal is now sold as a cure-all type of herb to prevent and treat colds and flu, strengthen the immune system, potentiate insulin, cleanse vital organs, and promote the functioning capacity of the heart, lungs, liver, spleen, pancreas, and colon.
Pharmacology
The active ingredients in goldenseal are a group of benzylisoquinoline alkaloids, the most abundant of which are berberine and hydrastine. Alkaloids are a diverse group of alkaline nitrogen-containing compounds made by many plants from a small group of amino acids. Many have pharmacological activity. The chloride salt of berberine is responsible for goldenseal’s yellow color. Most of goldenseal’s alleged medicinal effects have been linked to berberine, with recent studies confirming the lack of antibacterial activity of other constituents.5
The active ingredients in goldenseal belong to the group of plant chemicals called:
a. flavonoids.
b. diterpenes.
c. alkaloids.
d. steroids.
Mechanism of Action
The mode of action of goldenseal and berberine in humans is not understood well. Berberine (also isolated from barberry, Oregon grape root, golden thread, and several Chinese herbs) has antimicrobial effects, inhibiting the adherence of microorganisms to host cells.5 Berberine has in vitro antimicrobial activity against a wide variety of microbes, including Bacillus, Streptococcus, and Candida organisms.6 Antiviral activity has not been reported for berberine.
Goldenseal is believed to relieve colds and flu by increasing the flow of mucous and causing the release of more antibodies.7 Goldenseal allegedly acts in humans as an "alterative," an herbalist’s term for substances that gradually produce beneficial changes in the body by stimulating natural healing processes. In this case, goldenseal’s GI effects are said to result from "increasing deficient flow but decreasing excessive flow" of various mucous secretions.7
Animal Studies
One animal study examined goldenseal’s effect on the rat immune system.8 Animals given goldenseal in their drinking water showed significantly elevated IgM antibody levels compared to control rats during the first two weeks, but not in the four subsequent weeks. Levels of IgA antibodies did not differ between the two groups.
Another animal study provides some support for goldenseal’s relief of cold symptoms.9 Mice with drug-induced diabetes were fed a diet containing 6.25% by weight of goldenseal to investigate its reputation as a natural diabetes treatment. No significant changes in plasma glucose and insulin concentrations were detected, but hyperphagia and polydipsia were significantly reduced.
Clinical Studies
A search of MEDLINE, TOXLINE, and International Pharmaceutical Abstracts (using the terms goldenseal, golden seal, hydrastis, and berberine) found no clinical studies using goldenseal. Several goldenseal monographs also were consulted, and none reported clinical studies. A clinical study of giardiasis and berberine found it active against Vibrio cholerae, protozoa, and fungi.10
Goldenseal contains 2-4% of berberine, so one would have to take 26 commercial 500 mg goldenseal capsules daily to obtain the berberine dose typically given in the referenced clinical studies. Twenty-six capsules (or 13 g) daily far exceeds the usual recommended dose.7
The active ingredient in goldenseal has shown activity as an:
a. insulin-regulating compound.
b. antibacterial agent.
c. estrogen replacement agent.
d. antiviral agent.
Formulation
Goldenseal reportedly enhances the effects of echinacea and is frequently added to other herbal preparations. It is available as dried root and rhizome in capsules, tinctures, extracts, tablets, salves, and ointments. For colds and flu, one or two 500 mg capsules are recommended 2-3 times daily. Alternatively, one teaspoonful of herb (the contents of 2 or 3 capsules) or tincture can be added to a cup of boiling water to make a tea taken three times daily. Stronger mixtures are recommended for external use only.
Adverse Effects
Large doses or prolonged use of goldenseal can cause nausea, vomiting, paresthesia, hypertension, and respiratory failure. Fatalities have been reported.11 Goldenseal (10 capsules; strength not reported) is one of several berberine-containing herbs used as abortifacients.7 Berberine displaces serum-bound bilirubin, raising blood levels and increasing the risk of brain damage in infants with previously raised bilirubin levels.12
Adulteration
Widespread use of goldenseal has led to over-collection and deforestation of the plant, leading to high prices and adulteration with less expensive berberine-producing herbs.13 These include Chinese goldthread (Coptis chinensis), yellow root (Xanthorhiza simplicissima), and Oregon grape (Mahonia aquifolium or Berberis vulgaris), which have different overall effects. Oregon grape in particular has been associated with adverse effects, especially diarrhea, nephritis, confusion, and stupor.14 The European Union’s drug regulating agency in 1996 listed Oregon grape as an Herbal Drug with Serious Risks because of its berberine content.7
Conclusion
The likely active ingredient in goldenseal has in vitro antibacterial, antifungal, and antiparasitic activity. However, its systemic efficacy, especially against viral infections, remains unproven. One animal study showed it may induce short-lasting immune system stimulation.
Recommendation
Given goldenseal’s serious adverse effects, its popular use for colds and flu appears unwarranted. Goldenseal certainly should not be used during pregnancy or lactation. Traditional usage has primarily been as a topical antimicrobial, and berberine does have broad antimicrobial activity. Ironically, goldenseal has fallen prey to the same tendency toward overuse as have prescription antibiotics, resulting in endangerment of the plant’s wild variety.
Which group of patients should most certainly limit or avoid use of goldenseal?
a. Older men
b. Teenagers
c. Immunosuppressed adults
d. Pregnant women
Dr. O’Mathúna is Professor of Bioethics and Chemistry at Mount Carmel College of Nursing, Columbus, OH.
References
1. Blumenthal M. Herb market levels after five years of boom. HerbalGram 1999;47:64-65.
2. McGuffin M. AHPA goldenseal survey measures increased agricultural production. HerbalGram 1999;46:66-67.
3. Hobbs C. Golden seal in early American medical botany. Pharm Hist 1990;32:79-82.
4. Foster S, Tyler VE. Tyler’s Honest Herbal. 4th ed. Binghamton, NY: Haworth Herbal Press; 1999:195-197.
5. Gentry EJ, et al. Antitubercular natural products: Berberine from the roots of commercial Hydrastis canadensis powder. Isolation of inactive 8-oxotetra-hydrothalifendine, canadine, beta-hydrastine, and two new quinic acid esters, hycandinic acid esters-1 and -2. J Nat Prod 1998;61:1187-1193.
6. Pepeljnjak S, Petricic J. The antimicrobic effect of berberine and tinctura berberidis. Pharmazie 1992;47:307-308.
7. Bergner P. The Healing Power of Echinacea, Golden-seal, and Other Immune System Herbs. Rocklin, CA: Prima Publishing; 1997.
8. Rehman J, et al. Increased production of antigen-specific immunoglobulins G and M following in vivo treatment with the medicinal plants Echinacea angustifolia and Hydrastis canadensis. Immunol Lett 1999;68:391-395.
9. Swanston-Flatt SK, et al. Evaluation of traditional plant treatments for diabetes: Studies in streptozotocin diabetic mice. Acta Diabetol Lat 1989;26:51-55.
10. Gupte S. Use of berberine in treatment of giardiasis. Am J Dis Child 1975;129:866.
11. Lewin NA, et al, eds. Goldfrank’s Toxicological Emergencies. 5th ed. Norwalk, CT: Appleton & Lange; 1996:963-979.
12. Chan TY, et al. Chinese herbal medicines revisited: A Hong Kong perspective. Lancet 1993;342:1532-1534.
13. Betz JM, et al. Differentiation between goldenseal (Hydrastis canadensis L.) and possible adulterants by LC/MCS of the alkaloids. FDA 1997 Science Forum poster abstract. Available at: http://vm.cfsan.fda.gov/~frf/eweb.filelist/forum97.filelist/97a01.htm. Accessed March 31, 2000.
14. Fetrow CW, Avila JR. Professional’s Handbook of Complementary & Alternative Medicines. Springhouse, PA: Springhouse Publishing Company; 1999.
May 2000; Volume 3; 56-58
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