Phytochemical Investigation of the Estrogenic Aerial Parts of Cimicifuga racemosa (L.) Nutt(Ranunculaceae)

The roots of Cimicifuga racemosa (L.) Nutt. (Black Cohosh, syn: Actea racemosa) have been widely used as a remedy for menopausal symptoms. Despite many in vitro bioactivity studies and positive data on in vivo efficacy, the mechanism of action of C. racemosa remains unclear. The focus of this study was on the aerial parts of C. racemosa rather than the well-studied roots/rhizomes. Where as traditional uses of roots/rhizome have implied that the estrogenicity is a property of the roots/rhizome parts, while there are almost no studies dealing with the aerial parts. Moreover, it is reasonable to hypothesize that roots/rhizome extracts can be adulterated with aerial parts, due to the burdensome wild collection procedure, but also due to morphologic ambiguities. Thus, it is important to gain knowledge about the aerial parts of C.racemosa. After sequential extractions with petroleum ether (PE), dichloromethane (DCM), and 75% methanol (MeOH), bioassay guided fractionation regarding estrogenicity was carried out using an estrogen receptor (ER) binding assay. After two steps of fractionation of the total extract using HSCCC and FCPC, the activity was enriched in a fraction that showed more than 80% inhibition in both ER∀(84∀4%) and ER∃(91∀1%) assays at a concentration of 200 (g/ml. The presence of several cycloartane triterpenes was indicated by the characteristic proton NMR signals (two dd signals of H19∀ and ∃ resonating at approx. 0.54 ppm, 0.30 ppm, respectively) in the active fraction. One major aglycone was identified as cimigenol, which has not been previously described as a genuine plant constituent.