Black Cohosh: Insights into its Mechanism(s) of Action

• Published in: Infectious diseases Vol. 3; pp. 21 - 32
• Main Authors: Ruhlen, Rachel L., Sun, Grace Y., Sauter, Edward R.
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.2008; Sage Publications Ltd. (UK); Sage Publications Ltd; Libertas Academica
• Subjects: Alternative medicine; Antioxidants; Biological response modifiers; Estrogen; Health aspects; Hormone therapy; Menopause; Nitric oxide; Original Research; Saponins; Serotonin uptake inhibitors; Terpenes; Women; OPG, osteoprotegerin; estrogen; nitric oxide; SSRI, selective serotonin reuptake inhibitor; inflammatory; NOS, nitric oxide synthase; ER, estrogen receptor; CNS, central nervous system; botanical; NO, nitric oxide; BCE, black cohosh extract; SERM, selective estrogen receptor modulator; LPS, lipopolysaccharide; IFNγ, interferon γ; ROS, reactive oxygen species; Black cohosh; complementary and alternative medicine
• ISSN: 1177-3936; 1178-6337; 1177-3936
• DOI: 10.4137/117863370800300002

The Women's Health Initiative found that combination estrogen and progesterone hormone replacement therapy increases breast cancer and cardiovascular disease risk, which compelled many women to seek herbal alternatives such as black cohosh extract (BCE) to relieve their menopausal symptoms. While several clinical trials document the efficacy of BCE in alleviating menopausal symptoms, preclinical studies to determine how BCE works have yielded conflicting results. Part of this is because there is not a universally accepted method to standardize the dose of black cohosh triterpenes, the presumed active ingredients in the extract. Although the mechanism by which BCE relieves symptoms is unknown, several hypotheses have been proposed: it acts 1) as a selective estrogen receptor modulator, 2) through serotonergic pathways, 3) as an antioxidant, or 4) on inflammatory pathways. We found that while the most prominent triterpene in BCE, 23-epi-26-deoxyactein, suppresses cytokine-induced nitric oxide production in brain microglial cells, the whole BCE extract actually enhanced this pathway. A variety of activities have been reported for black cohosh and its compounds, but the absorption and tissue distribution of these compounds is unknown.