Blue cohosh is an early spring perennial herb whose yellowish-green flowers mature into bitter, bright blue seeds. It is found throughout woodlands of the eastern and midwestern United States, especially in the Allegheny Mountains. The matted, knotty rootstock, col?lected in the autumn, is used for medicinal purposes. The root of an Asian species, C. robustum Maxim., has also been used medicinally.
Blue cohosh was used by Native Americans; , the name "cohosh" comes from the Algonquin name of the plant. It was used by Menomini, Meskawi, Ojibwe, and Potawatomi tribes for menstrual cramps, to suppress profuse menstruation, and to induce contractions in la?bor.1 It was widely used in 19th century Eclectic medicine as an emmenagogue, parturient, and antispasmodic. It continues to be used for regulating the menstrual cycle and for inducing uterine contractions.
The quinolizidine alkaloids anagyrine, baptifoline, and N-methylcytisine were isolated from blue cohosh rhizomes. Other lupine alkaloids have been detected? In addition to the quinolizidines, the aporphine alkaloid magnoflorine is found in substantial quantities. Levels of the major quinolizidine alkaloids in herbal preparations have been determined by gas chromatography. Blue cohosh root also contains triterpene saponins derived from hederagenin;5 however, these saponins have not been purified or elucidated by modern chemical techniques. The saponins of the related species C. robus?turn have recently been more thoroughly characterized as a series of hederagenin bisdesmosides.
N-methylcytisine (caulophylline) was found to be a nicotinic agonist in animals? and to displace [3H]nicotine from nicotinic acetylcholine receptors with 50 nm potency. It was essentially inactive at muscarinic receptors. Other quinolizidine alkaloids were considerably less potent nicotinic ligands, with anagyrine having IC50 values greater than 100 mcm in these test systems.
Magnoflorine has its own pharmacological properties, decreasing arterial blood pressure in rabbits and inducil1i hypothermia in mice, as well as inducing contractions in the isolated pregnant rat uterus and stimulating isolated guinea pig ileal preparations in cell membranes. The blue cohosh saponins have uterine stimulant effects, as well as cardiotoxicity presumably due to vasoconstricTIon of coronary blood vessels.1O Extracts of Caulophyllum given to rats were found to inhibit ovulation and affect the uterus. The saponins of the Siberian species C. robus. turn (caulosides) have antimicrobial activity. A mecha. nism for cytotoxicity has been suggested for cauloside C involving formation of pH-dependent channels.
Blue cohosh berries are poisonous to children when consumed raw although the roasted seeds have been used as a coffee substitute. The root can cause contact dermatitis. The alkaloid anagyrine is a teratogen in ruminants,15 causing "crooked calf syn. drome." Another quinolizidine alkaloid in the plant, N. methylcytisine, was teratogenic in a rat embryo culture. The skeletal malformations seen in calves have been postulated to be due to the action of the quinolizidine alkaloids on muscarinic and nicotinic receptors of the fetus, preventing normal fetal movements required for proper skeletal development.
A case was reported in which a newborn human infant, whose mother was administered blue cohosh to promote uterine contractions, was diagnosed with acute MI associated with CHF and shock. The infant eventually recov. ered after being critically ill for several weeks. The FDA Special Nutritionals Adverse Event Monitoring System notes fetal toxicity cases of stroke and aplastic anemia following ingestion by the mother.
Blue cohosh root is a dangerous product that can be toxic to humans. While it appears to be effective for inducing uterine contractions, its toxici appears to outweigh any medical benefit.