Evaluation of triterpene glycoside estrogenic activity using LC/MS and immunoaffinity extraction

We present a study on the mass spectral as well as the binding, properties of three triterpene glycosides (cimicifugoside, cimiracemoside F, 27-deoxya ctein) contained in black cohosh to the ligand binding domain of estrogen r eceptor beta (ER-beta). Using affinity ultrafiltration and LC/ MS detection , initial experiments using estradiol and the phytoestrogens daidzein and g enistein (compounds known to bind ER-beta were performed to serve as positi ve controls. The same affinity techniques and LC/MS procedures were then em ployed to show that neither the triterpene glycosides nor their enzymatical ly prepared aglycons bound significantly to ER-beta, except for 27-deoxyact ein aglycon, which showed weak binding affinity (4%). Additionally, metabol ites of the aglycons were prepared by incubation with female human liver mi crosomes and subjected to binding experiments with ER-beta. No significant binding of the metabolites to the receptor was observed. Further studies ar e needed to fully characterize whether these triterpene glycosides as well as other components of black cohosh in this plant extract bind to the estro gen receptor alpha (ER-alpha).