title: Black cohosh (Actaea racemosa, Cimicifuga racemosa) behaves as a mixed competitive ligand and partial agonist at the human mu opiate receptor.
abstract: Black cohosh is a commonly used botanical dietary supplement for the treatment of climacteric complaints. Because the opiate system in the brain is intimately associated with mood, temperature, and sex hormonal levels, the activity of black cohosh extracts at the human mu opiate receptor (hMOR) expressed in Chinese hamster ovary cells was investigated. The 100% methanol, 75% ethanol, and 40% 2-propanol extracts of black cohosh effectively displaced the specific binding of [3H]DAMGO to hMOR. Further studies of the clinically used ethanol extract indicated that black cohosh acted as a mixed competitive ligand, displacing 77 +/- 4% [3H]DAMGO to hMOR (Ki = 62.9 microg/mL). Using the [35S]GTPgammaS assay, the action of black cohosh was found to be consistent with an agonist, with an EC50 of 68.8 +/- 7.7 microg/mL. These results demonstrate for the first time that black cohosh contains active principle(s) that activate hMOR, supporting its beneficial role in alleviating menopausal symptoms.
authors.affiliation: Department of Medicinal Chemistry and Pharmacognosy, UIC/NIH Center for Botanical Dietary Supplements Research and Program for Collaborative Research in the Pharmaceutical Sciences, University of Illinois, Chicago, Illinois 60612, USA.
authors.forename: Mee-Ra
authors.initials: MR
authors.lastname: Rhyu
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Donna E
authors.initials: DE
authors.lastname: Webster
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Fabricant
authors.forename: Norman R
authors.initials: NR
authors.lastname: Farnsworth
authors.forename: Z Jim
authors.initials: ZJ
authors.lastname: Wang
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D016466:CHO Cells; D031885:Cimicifuga / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000378:metabolism; D006801:Humans; D010936:Plant Extracts / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000819:agonists* / Q000378:metabolism*; D014316:Tritium
chemical_list: D010936:Plant Extracts; D017450:Receptors, Opioid, mu; D014316:Tritium; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-