What is Black cohosh?
Definition
Black cohosh is a medicinal plant that originates from eastern North America. Its botanical name is Cimicifuga racemosa (synonyms Actaea racemosa or Actea macrotys), which has been used by native American Indians and Europeans for women’s conditions such as chronic ovaritis and amenorrhea (ref 1). Most recently, black cohosh has been used as a therapy for menopausal symptoms such as hot flushes. The characteristic chemical constituents of the roots and rhizomes of black cohosh include cycloartenol-type triterpenoids, and cimicifugoside, as well as cinnamic acid derivatives (ref 2). The commonly used dosage for black cohosh is 40 to 80 mg daily.
Prevalence of use
Black cohosh was first listed in the U.S. Pharmacopoeia in 1830 under the name "black snakeroot". This herb was introduced for use in Germany in the 1940s for the treatment of menopausal discomfort, dysmenorrhoea, and climacteric neurovegetative complaints (ref 3). An investigation in California, US, showed that 72% of women with breast cancer used at least one form of complementary and alternative therapy, in which herbal preparations accounted for a substantial proportion (ref 4).
Theory
Breast cancer treatment can cause premature menopause, which results in hot flushes before the physiological menopause. Hot flushes are also the main adverse effect of one common anti-breast cancer treatment, tamoxifen. Hormone replacement therapy (HRT) for hot flushes in breast cancer patients may not be appropriate because of evidence of a relationship between long-term use of HRT and increased risk of breast cancer and cardiovascular disease (ref 5), and potential stimulation of cancer growth by HRT (ref 6). Therefore, there is an increasing interest in seeking safe and effective alternatives to HRT for the treatment of menopausal symptoms in breast cancer patients. Herbal preparations such as black cohosh are used as alternatives to HRT in the treatment of hot flushes (ref 7). The mechanism of action was proposed as being mediated by an inhibitory effect on the hypothalamus, or an effect on neurotransmitters (ref 8), or a possible oestrogenic effect from the phyto-oestrogens (ref 9).
Providers
Black cohosh products are commercially available on the market. Remifemin®, an isopropanolic extract of black cohosh standardised to contain 1 mg of triterpenes per 20 mg of extract (ref 10). The other standardised ethanolic extract of black cohosh is BNO 1055 (Menofem®/Klimadynon®), BIONORICA (ref 11). There are numerous other herbal preparations made from black cohosh: for example, in Switzerland there are four registered drugs, for instance, Cimifemin®.
Legal issues
In most European countries and the US, plant-based preparations including herbal remedies are regulated as dietary supplements. However, the recent European Directive on traditional herbal medicinal products allows herbal medicines to be registered as drugs if they have been used medicinally for at least 30 years (including at least 15 years within the EU countries) (ref 12).
References
1.Anonymous. Cimicifuga racemosa. Monograph. Alternative Medicine Review 2003; 8(2):186-9.
2.Mahady GB, Fabricant D, Chadwick LR, Dietz B. Black cohosh: an alternative therapy for menopause? Nutr Clin Care 2002;5(6):283-9
3.Blumenthal M, ed. Herbal Medicine: Expanded Commission E Monograph. 1st ed. Newton, Mass: Integrative Medicine Communications; 2000.
4.Adler S. Complementary and alternative medicine use among women with breast cancer. Medical Anthropology Quarterly 1999;13(2):214-22.
5.Rossouw JE, Anderson GL, Prentice RL, LaCroix AZ, Kooperberg C, Stefanick ML, Jackson RD, Beresford SA, Howard BV, Johnson KC, Kotchen JM, Ockene J; Writing Group for the Women's Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial. JAMA. 2002;288(3):321-33.
6.Schairer C, Lubin J, Troisi R, Sturgeon S, Brinton L, Hoover R. Menopausal estrogen and estrogen-progestin replacement therapy and breast cancer risk. JAMA. 2000;283(4):485-91.
7.Graf MC, Geller PA. Treating hot flushes in breast cancer survivors: a review of alternative treatments to hormone replacement therapy. Clin J Oncol Nurs 2003; 7(6):637-40.
8.Einer-Jensen N, Zhao J, Andersen KP, Kristoffersen K. Cimicifuga and Melbrosia lack oestrogenic effects in mice and rats. Maturitas 1996; 25:149-53.
9.Kruse SO, Lohning A, Pauli GF, Winterhoff H, Nahrstedt A. Fukiic and piscidic acid esters from the rhizome of Cimicifuga racemosa and the in vitro estrogenic activity of fukinolic acid. Planta Med 1999; 65(8):763-4.
10.Piersen CE. Phytoestrogens in botanical dietary supplements: implications for cancer. Integrative Cancer Therapies 2003; 2(2): 120-38.
11.Popp M, Schenk R, Abel G. Cultivation of Cimicifuga racemosa (L.) nuttal and quality of CR extract BNO 1055. Maturitas 2003; 44 (Suppl 1):S1-7.
12.De Smet P. Herbal medicine in Europe – relaxing regulatory standards. N Engl J Med 2005;352:1176-8.
