What is Black Cohosh?
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Thanks to the University of North Carolina School of Pharmacy for the use of this article!
General DescriptionBlack cohosh can be found in shady woodlands of the United States and Canada, particularly in the southeast, northern Oregon, Washington, and Ontario. The plant is hardy and tall with feathery racemes of white blossoms measuring 1 to 3 feet long. The flowers bloom in June and July and thrive in moist, shady areas. The stout, black rhizome along with the root are used for medicinal effects.
Chemical Composition
Black cohosh contains cimicifugin (macrotin) which has estrogenic effects. Also found in assay are acetein (antihypertensive effects) and ferulic/isoferulic acids (anti-inflammatory effects). The following components can also be found: isoflavones, salicyclic acid, tannins, resins, starch, and sugars.
History and Folk Use
The American Indians boiled black cohosh root in water and drank it for rheumatism, sore throat, rattlesnake bite, gynecological problems, and childbirth. In the 19th century, some physicians used black cohosh for fever, rashes, insomnia, malaria, gynecological problems. For treatment of the latter, black cohosh was often combined with alcohol to produce "Pinkham's Compound."
Pharmacology
Estrogenic Effects
Black cohosh may selectively reduce pituitary LH serum concentrations as well as reduce LH's ability to bind to receptors in the hypothalamus. This results in the alleviation of menstrual and menopausal discomfort.
Anti-inflammatory effects
Ferulic and isoferulic acid, both found in black cohosh, are potent inhibitors of interleukin-8, which is produced upon stimulation of an inflammatory response and serves as a chemoattractant for neutrophils. By inhibiting these acids, inflammation is inhibited.
Anti-hypertensive effects
Black cohosh reduced arterial pressure by decreasing constriction of the peripheral blood vessels. The result is a slight decrease in blood pressure.
Expectorant
By increasing blood flow to the lungs and increasing membrane secretions, black cohosh can thin respiratory mucous, facilitating its removal.
Clinical Applications
Menopause
Black cohosh has been widely studies in the treatment of menopause. In Germany, a commercial formulation, Remifemin®, is available and is the most popular alternative to estrogen therapy. This formulation contains 1 mg of triterpenes calculated as 27-deoxyacteine per tablet. In 1997, over ten million monthly units of this extract were sold in the United States, Germany, and Australia.
One large open study (Stolze, H) involving 131 physicians and 629 female patients showed that cimicifuga extract was beneficial in improving menopausal symptoms in over 80% of patients within 6-8 weeks. The following table summarizes symptomatic relief provided by black cohosh:
Cimicifuga in the Treatment of Menopause Symptom % No Longer Present % Improved Total % Improved Tinnitus 54.8
38.1
92.9
Heart palpitation 54.6
35.2
90.4
Profuse perspiration 49.9
38.6
88.5
Vertigo 51.6
35.2
86.8
Hot flashes 43.3
43.3
86.6
Nervousness/irritability 42.4
43.2
85.6
Headache 45.7
36.2
81.9
After 6-8 weeks, complete resolution of symptoms was evident in a large percentage of participants. The extract was well-tolerated, with only 7% of patients reporting mild transient stomach complaints.
In a double-blind study (Warnecke, G), 60 patients were given either cimicifuga extract (2 tablets twice per day, providing a daily dosage of 4 mg 27-deoxyacteine), conjugated estrogens (0.625 mg daily), or diazepam (2 mg daily) for 12 weeks. The Kupperman Menopausal Index was used to assess symptomatic relief. This index quantifies symptomatic involvement by grading severity: Severe = 3; Moderate = 2; Mild = 1; Not present = 0. A total score is achieved by adding all scores together. Symptoms assessed are as follows:
Depressive moods, Feelings of vertigo, Headache, Heart palpitation, Hot flashes, Joint pain, Loss of concentration, Nervousness/irritability, Profuse perspiration, Sleep disturbances
The following table summarizes the results:
Effect of Cimicifuga on Kupperman Menopausal Index Compared to Conjugated Estrogens and Diazepam Treatment Group Beginning At 12 Weeks Cimicifuga 35
14
Conjugated Estrogens 35
16
Diazepam 35
20
Another double-blind study (Stoll, W), 80 patients were given either cimicifuga extract (2 tabs BID, providing 4 mg 27-deoxyacteine daily), conjugated estrogens (0.625 mg daily), or placebo for 12 weeks. Black cohosh produced better Kupperman Menopausal Index scores, Hamilton Rating Scale for Anxiety scores, and greater improvement in the patients' vaginal lining (dramatic increase in the number of superficial cells). Daily occurrences of hot flashes dropped from an average of 5 to less than 1 in the cimicifuga group. The same drop in the estrogen group was only from 5 to 3.5.
Other applications:
Black cohosh may be effective in inflammatory conditions such as rheumatoid arthritis. It also may be helpful as an expectorant.
Toxicity
The BGA (the German equivalent to the FDA in the US) does not list any contraindications or limitations for the use of cimicifuga. Researchers have sought to discover if black cohosh may stimulate the growth of estrogen-dependent breast tumor cells. These in vitro studies have shown no stimulatory effects - in fact, the effects seem to be inhibitory. In fact, combination of Remifemin® with tamoxifen has been shown to potentiate the effects of tamoxifen.
Thorough toxicology studies have been performed on Remifemin® and have not shown to produce any teratogenic, mutagenic, or carcinogenic effects. One 6-month study in rats used dosages of 1,800 mg/kg (~90 times the therapeutic dose) and showed no adverse effects.
The German Commission E recommends that treatment with cimicifuga be limited to 6 months (the standard recommendation for hormone replacement therapy also). However, this recommendation was made prior to the aforementioned toxicology studies. Current knowledge suggests that cimicifuga is appropriate and safe for long-term continued use in patients who are not pregnant and with no history of breast cancer. (Neither of these conditions has been proven to be a contraindication to the use of black cohosh. However, the lack of extensive research in these populations warrants caution in the use of cimicifuga.)
Some side effects have been reported: dizziness, nausea, vomiting, diarrhea, abdominal pain, visual dimness, headache, tremors, joint pains, and depressed heart rate.
Drug Interactions
Oral contraceptives / ERT
Because black cohosh appears to contain some estrogenic activity, side effects of OCs containing estrogen may be more pronounced. The same holds true for estrogen replacement therapy (such as conjugated estrogens).
Dosage
- Powdered root or as tea: 1-2 grams
- Fluid extract (1:1): 4 mL (1 teaspoonful)
- Solid (dry powdered) extract (4:1): 250-500 mg
- Remifemin® (containing 1 mg of 27-deoxyacteine per tablet): 2 tablets twice daily
References:
Andersen, KP, et al. Cimicifuga and melbrosia lack oestrogenic effects in mice and rats. Maturitas. 25(2):149-53, 1996 Oct.
Castelman, M. The Healing Herbs. Rodale Press, Emmaus, PA. 1991. Pp. 75-78.
Covington, TR, et al. Handbook of Nonprescription Drugs. American Pharmaceutical Association, Washington, DC. 1996. P. 705-706.
Duker, EM, et al. The use of black and blue cohosh in labour. New Zealand Medical Journal. 109(1032):410-11, 1996 Oct 25.
Giesler, Michelle and Kimberly Jones. Cimicifuga Racemosa: Black Cohosh. Presentation handout, Pharmacy 100, Fall 1997. UNC-Chapel Hill, School of Pharmacy.
Hirabayashi, T, et al. Inhibitory effect of ferulic acid and isoferulic acid on murine interleukin-8 production in response to influenza virus infections in vitro and in vivo. Planta Medica. 61(3):221-6, 1995 June.
Moore, M. Medicinal Plants of the Pacific West. Red Crane Books, Santa Fe, NM. 1993. Pp. 74-79.
Murray, MD. The Healing Power of Herbs. Prima Publishing, Rocklin, CA. 1996. p 376.
Murray, Michael and Joseph Pizzorno. Encyclopedia of Natural Medicine. Prima Publishing, Rocklin, CA. 1998. pp. 639-641.
Stoll, W. "Phytopharmacon Influences Atrophic Vaginal Epithelium. Double-Blind Study: Cimcifuga vs. Estrogenic Substances," Therapeuticum 1(1987): 23-31.
Stolze, H. "An Alternative to Treat Menopausal Complaints," Gyne 3(1982): 14-6.
Tyler, VE. The Honest Herbal. Pharmaceutical Products Press, Binghamton, NY. 1993. pp.45-46.
Warnecke, G. "Influencing Menopausal Symptoms with a Phytotherapeutic Agent," Med Welt 36 (1985): 871-4.
Web sites:
http://www.viable-herbal.com
http://www.botanical.com
http://ncnatural.com/wildflwr
http://www.mothernature.com
http://www.a-better-way.com
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