tiviral, antiproliferative effects of some triterpenene glycosides and the inhibitory effect of neutrophil elastase and collagenolytic activity by cinnamic acid

Cimicifuga racemosa L. NUTT), have since long been used as a popular herbal medicine to alleviate menopausal symptoms. Apart from the use of Cimicifuga racemosa extracts (CR) for treating menopausal symptoms mainly in the European countries and United States, CR have long been used for the treatment of rheumatism, and as antipyretic and analgesic agents in Japan and China. An isopropanolic extract of black cohosh (iCR) has been shown repeatedly to be devoid of proliferative activity on ER positive breast cancer cells, even iCR inhibited the growth of both estrogendependent MCF-7 and estrogen-independent MDA-MB231 human breast cancer cells. We recently demonstrated that apoptosis, the essential regulatory mechanism associated with many autoimmune disorders, malignant tumours and viral infections, is one underlying mechanism responsible for the observed inhibition of the proliferation of ER and ER breast cancer cells by iCR. As herbal extracts must be considered multi-component drugs, any influence on the balance between cell growth and programmed cell death should ideally be attributable to a single ingredient or at least an enriched fraction of closely related compounds. Two main classes of compounds have been isolated from the rhizomes of CR, triterpene glycosides (TTG, e.g. actein, 26-deoxyactein, cimigenol, cimiracemoside) and aromatic acids (e.g. caffeic, ferulic, isoferulic, fukiic, piscidic) and their derivates (cinnamic acid esters-cimicifugic acid A-H) which differ in their biological activity. According to recently published reports, these include cytotoxic, antitumor, antiviral, antiproliferative effects of some triterpenene glycosides and the inhibitory effect of neutrophil elastase and collagenolytic activity by cinnamic acid derivates. We therefore chose these two fractions, the fairly black cohosh-characteristic TTG and, due to their similarity to synthetic estrogenic compounds, the cinnamic acid esters (CAE). Furthermore, as the commercially available iCR preparations are exclusively for oral ingestion, we also tested whether the observed inhibition of proliferation and apoptosis induction would withstand simulated liver metabolism. Therefore we incorporated an incubation step in that we added rat liver S9 mix containing P450 enzymes to the cytotoxicity and apoptosis assays of iCR. The aim of our study in ER MCF-7 breast cancer cells was therefore twofold. Firstly, we compared the proliferation inhibiting and apoptosis inducing potential of iCR before and after S9-incubation. Then we tested two major fractions of iCR, namely TTG and CAE, for their share in the overall effect on programmed cell death as observed with unmodified iCR. We could verify that the cell growth inhibition exerted by iCR on ER breast cancer cells was due to apoptosis induction, that these effects withstood a metabolic activation system with S9 fraction and that a significant part of the extract’s activity was due to both TTG and CAE fractions.