PDF
(Download)
|
- Black Cohosh (Actaea racemosa syn. Cimicifuga racemosa)
- Menopause
- Climacteric Complaints
|
Date:
08-15-2013 | HC# 041354-478
|
Re: Black Cohosh as a Non-estrogenic Therapy for Menopausal Symptoms
Wuttke W, Jarry H, Haunschild J, Stecher G, Schuh M, Seidlova-Wuttke D. The
non-estrogenic alternative for the treatment of climacteric complaints: Black
cohosh (Cimicifuga or Actaea racemosa). J Steroid Biochem Mol Biol. February 28, 2013; [epub ahead of
print]. doi: 10.1016/j.jsbmb.2013.02.007.
Concerns about the safety of hormone replacement therapy (HRT) have stimulated efforts
to find alternative treatments for adverse menopausal symptoms or
"climacteric complaints." Phytoestrogens (plant-derived estrogen
mimetics) have been shown to have minimal, if any, efficacy and promote
estrogen-dependent carcinomas. The ideal plant-based therapy would be devoid of
estrogenic effects in the mammary glands and uterus while having beneficial
effects on climacteric symptoms and bone health. This paper summarizes the
evidence pertaining to the leading non-estrogenic herbal medicine that has been
clinically demonstrated to be efficacious in the treatment of menopausal
symptoms, black cohosh (Actaea racemosa
syn. Cimicifuga racemosa).
In
most countries where black cohosh is regulated as a prescription medication (i.e.,
countries in Europe), health authorities require that black cohosh not be taken
by patients with estrogen-dependent tumors. This is primarily due to a study published
in 1985 that said that the estrogenic isoflavone formononetin was found in a
black cohosh extract. This finding was never confirmed in subsequent analyses.
Isoflavones stimulate the growth of estrogen-dependent cancer cells in vitro and
stimulate uterine growth in vivo. Newer studies have used high-performance
liquid chromatography (HPLC) to try to identify formononetin in black cohosh
extracts. These analyses demonstrated that formononetin was not present in the
various extracts tested.
According
to the authors, there is ample evidence that extracts of black cohosh do not
contain estrogenic compounds—they do not bind to alpha or beta estrogen
receptors. Black cohosh dose-dependently inhibited the proliferation of estrogen-dependent
cancer cells in vitro, and inhibited estradiol-stimulated proliferation of estrogen-dependent
cancer cells and estrogen-receptive endometrial cancer cells. Moreover, animal studies
have demonstrated that: (1) black cohosh extracts did not have estrogenic
actions in the mammary gland, (2) oral black cohosh inhibited typical mammary
tumors in rats, and (3) uterine weight and endometrial thickness (which
increase in response to estrogens) remained unaffected in rats treated with
oral black cohosh.
In
humans, 12 months of black cohosh treatment did not affect mammary gland
density, and 12 weeks of treatment did not alter mammary gland cell morphology
or proliferation (dosages not reported). A case-controlled study of 949
patients with breast cancer revealed that black cohosh had a significant breast
cancer protective effect (study details not provided). In addition to these studies
evaluating mammary tissue, 2 studies demonstrated that black cohosh (treatment
durations: 1 year or 3 months; doses not reported) had no effect on endometrial
thickness. The authors conclude that black cohosh has no estrogenic effects on
the endometrium and poses no risks for the uterus.
The
authors briefly describe 6 randomized, placebo-controlled studies conducted in
Europe that demonstrated that black cohosh decreases climacteric complaints; these
studies evaluated German/Swiss extracts of black cohosh produced in accordance with
pharmaceutical quality standards. They also reference 2 studies conducted in
the United States (US) that concluded that black cohosh had no significant
effect on climacteric complaints and the authors suggest two possible
explanations for these negative results: (1) the US trials used a much higher
dose than the European studies, and (2) possible adulteration of the US study material.
They point out that black cohosh products in the American market are sold as
food supplements and not pharmaceuticals, and studies have found that some black
cohosh supplements contained Asian species of Cimicifuga which have different pharmacological effects, as well as
other adulterants. They also describe a third US study which found that black
cohosh extract standardized to 2.5% triterpenes was efficacious, while a triterpene-free
extract was ineffective.
The
authors conclude that the preponderance of evidence indicates that black cohosh
has beneficial effects on climacteric complaints without having adverse estrogenic
effects on mammary gland or uterine tissue. They emphasize that this lack of an
estrogenic effect on peripheral tissue should not be confused with data that
demonstrate that black cohosh has an estrogen-like effect on central nervous
system neurotransmitters. Most of the studies described evaluated a proprietary,
aqueous/ethanolic extract of black cohosh called BNO 1055® (Bionorica
SE; Neumarkt i.d.OPf., Germany). The authors conclude that the black cohosh
extract BNO 1055 may be a good non-estrogenic alternative for the treatment of climacteric
complaints in menopausal women, including patients with breast cancer.
—Heather S. Oliff,
PhD
|