PHARMACOLOGY AND BIOLOGICAL
ACTIVITIES
Extracts of the rhizome have failed to show
either estrogenic or antiestrogenic activity
in either animal orin vitrostudies.8–10How-
ever, selective estrogen receptor modulating
(SERM) activity has been demonstrated fol-
lowing oral administration of black cohosh
extracts(e.g.,inhibitionofpituitaryluteinizing
hormone secretion^11 and estrogenic-like ef-
fects in fat tissue and osteoblasts in the bone
of rats).^10 In vitrostudies have shown that the
triterpene glycoside fraction inhibits the
growth of human breast cancer cells,^12 that
extracts of the rhizome show serotonin recep-
tor-binding^8 and dopaminergic activity,^9 and
that cimicifugoside exhibits nicotinic acetyl-
cholinereceptor(nAChR)agonistactivity.^13 In
a rat model of hot flashes, a standardized
ethanolic-aqueous extract of the rhizome ad-
ministeredorallyreducedthesymptomsandin
abehavioraltestinrats,showedantidepressant
activity.^14 The extract also reduced the loss
of bone mineral density in ovariectomized
rats.^10
Clinical trials of standardized isopropano-
lic extracts of the rhizome (randomized, dou-
ble-blind, placebo-controlled) have found sig-
nificant benefits in thetreatment of menopause
symptoms (MCKENNA), including an improve-
ment in bone metabolism.^15
TOXICOLOGY
A critical review on clinical studies of black
cohosh in the treatment of menopausal symp-
toms concluded that specific extracts of the
rhizome are safe alternatives to estrogen ther-
apy. In trials of black cohosh preparations
involving over 2800 patients, the incidence
of adverse effects was 5.4%; the majority
(97%) were minor and none attributed to black
cohosh were serious.^16 An isopropanolic ex-
tract failed to increase estrogen-dependent
mammary tumors in rats^17 and in a rat model
of endometrial cancer, failed to increase
growth or metastasis of the primary tumor.^18
No toxic effects were found in humans admin-
istered a fluidextract oftherhizome at doses of
up to 890 mg/day. Rats administered an iso-
propanolic extract (up to 5 g/kg) for 26 weeks
showed no organ toxicity. The minimum acute
lethal oral dose of a tincture of black cohosh in
rats was reported to be>1 g/kg. No mutage-
nicity was foundfrom an isopropanolicextract
in the Ames test (MCKENNA).USESMedicinal, Pharmaceutical, and Cosmetic.
Used in certain analgesic and tonic prepara-
tions, among others. In European phytomedi-
cine, isopropanol or ethanol extracts of the
dried rhizome standardized to triterpene gly-
coside contents are used in treating menopaus-
al symptoms, menstrual disorders, including
premenstrual discomfort, dysmenorrhea, and
postoperatively in patients after hysterectomy
or ovariectomy in the treatment of functional
deficits (BLUMENTHAL1;MCKENNA).Dietary Supplements/Health Foods. Used
alone and in herbal formulas to relieve pro-
blems related to menopause; capsules, tablets,
tinctures, fluid extract, crude root in infusion
or decoction (BRADLY;MCKENNA;WREN).Traditional Medicine. Used in treating
amenorrhea, postpartum and labor pains, uter-
ine disorders, support for natural uterine con-
tractions during labor, cough, dropsy, fever,
nervous disorders, smallpox, yellow fever,
lumbago, pain of acute rheumatism, head-
ache, hysteria, nervous system disorders, in-
fluenza, and itch.^16 Used by American Indian
tribes as a galactogogue, diuretic, to stimulate
menstruation, and in the treatment of colds,
rheumatic pains, constipation, coughs, and
kidney problems (MOERMAN).COMMERCIAL PREPARATIONSAvailable as crude and extracts (fluid, solid,
and powdered). Formerly official in N.F. and
U.S.P. Potencies of extracts are expressed only
in strength (seeglossary) based on weight-
to-weight ratio of crude and extracts.98 Black cohosh