Non-steroidal as well as steroidal aromatase inhibitors are currently being discussed as alternatives to tamoxifen in the first-line treatment of patients with hormone-dependent breast cancer. Many of these women are in a postmenopausal state and additionally troubled by climacteric complaints. Naturally occurring symptoms like hot flushes and night sweats can be triggered or augmented by anti-hormonal drugs. At the aromatase molecule, steroidal inhibitors like exemestane and formestane compete with the hormonal precursors for the substrate binding site and inactivate the enzyme irreversibly. An isopropanolic extract of the rootstock of black cohosh (iCR), which is a common comedication of aromatase inhibitors in breast cancer patients suffering from climacteric symptoms, contains triterpene glycosides and cinnamic acid esters, both of which possess structural similarities to steroids. We therefore tested a high dose of iCR, guaranteeing an effective uptake of 60 mg herbal substance per kg body weight and shown to influence rat bone and uterus, for putative interactions with two low dosing regimens of 3.5 mg or 5.0 mg formestane per animal and day. We chose a rat model of chemically induced breast cancer and evaluated tumor growth and serum estrogen levels. Compared to a tumor area of 1400 mm2 after 21 days of unopposed tumor growth, formestane treatment, irrespective of concomitant black cohosh application, significantly reduced neoplastic growth by 50%. Formestane also significantly reduced serum estrogen levels, an effect which was also not abolished by iCR. Therefore, in this experimental setting, when challenging two low doses of formestane with a high dose of iCR, our data do not raise concerns against combining aromatase inhibitors with black cohosh.

Herbal therapeutics are increasingly associated with herb drug interactions. The vast majority of the purported cases is unsubstantiated and misinterpreted. Pharmacological and clinical studies should only be demanded in cases of reliable evidence. First steps to be taken by manufacturers of herbal drugs should be in vitro studies with metabolizing systems like CYP and P-gp. Manufacturers of drugs that are metabolized by modulated systems should be requested to conduct drug specific interaction studies as necessary.

BACKGROUND:The isopropanolic extract of black cohosh (iCR)b has recently been reported to exert antiproliferative and apoptosis-inducing effects on estrogen receptor-positive MCF-7, as well as estrogen receptor-negative MDA-MB 231 human breast cancer cells. To broaden observations, the anti-invasive effects of iCR and its two major fractions triterpene glycosides (TTG) and cinnamic acid esters (CAE) were tested in highly invasive MDA-MB 231 cells.MATERIALS AND METHODS:The effect of drugs upon the invasive potential of MDA-MB231 cells was studied in BD Biocoat Matrigel invasion chambers over a period of 24 h.RESULTS:The suppression of invasion reached 51.8% at 77.4 microg/ml of iCR, an extract concentration where 89% of MDA-MB231 cells were viable. TTG and CAE reduced cell invasion by 34% and 25.5%, respectively, at a dose of 5 microg/ml. The motility of cells was only moderately reduced.CONCLUSION:In this study iCR was found to suppress tumor cell invasion without affecting cell viability. This result together with the antiproliferative and apoptosis-inducing effect of iCR suggest its use as a secure agent in postmenopausal hormone replacement therapy with additional chemopreventive activity.

Zusammenfassung Phytopharmaka werden in den letzten Jahren vermehrt mit Arzneimittelwechselwirkungen in Verbindung gebracht. Die Mehrzahl der Verdachtsmomente ist jedoch unbegründet und führt zu oft nicht nachvollziehbaren Schlussfolgerungen. Pharmakologische oder klinische Studien sollten nur dann gefordert werden, wenn tatsächlich belastbare Hinweise existieren. Die Hersteller von Phytopharmaka sollten in solchen Fällen Studien zur Beeinflussung metabolisierender Systeme wie CYP bzw. P-gp durchführen. Weiterführende Interaktionsstudien sind von den Herstellern der Arzneistoffe zu fordern, die über die beeinflussten Systeme verstoffwechselt werden.

In einer Vielzahl von Publikationen wurde vom antiproliferativen Effekt eines isopropanolischen Extraktes (iCR) aus dem Wurzelstock der Traubensilberkerze auf die menschliche, estrogenabhangige Brustkrebszellinie MCF-7 berichtet. Diese Proliferationshemmung ist auf die Induktion von Apoptose zuruckzufuhren und hier sollte nun untersucht werden, inwieweit die beiden Hauptfraktionen aus iCR, die Triterpenglykoside (TTG) und die Zimtsaureester (CAE), an diesem Effekt beteiligt sind. Die antiproliferative Wirkung wurde mittels des enzymbasierten WST-1-Assays, die Apoptose anhand von Lichtstreuverhalten und der Bindung von Annexin V an (apoptosetypische) Phosphatidylserinreste in MCF-7-Zellen quantifiziert. Eine 72stundige iCR-Behandlung fuhrte zu einer dosisabhangig reduzierten Zellproliferation, mit einer IC50 von 55,3 µg/ml Trockenruckstand, d. h. theoretisch 19,3 µg/ml TTG oder 2,7 µg/ml CAE. Die proliferationsinhibierende IC50 fur TTG lag bei 59,3 µg/ml und fur CAE bei 26,1 µg/ml. Apoptose wurde durch TTG ab einer Konzentration von 25 µg/ml verursacht und durch CAE ab einer Konzentration von 5 µg/ml. Somit zeigte diese Studie erstmals, das TTG und CAE die Proliferation estrogenabhangiger Brustkrebszellen uber Apoptoseinduktion hemmen. Zwar erschienen die Zimtsaureester als die wirksamere der beiden Fraktionen, jedoch kommt den TTG durch ihre deutlich hoheren Gehalte vermutlich eine zumindest ebenso grose Bedeutung zu. Schlusselworter: Apoptose, Traubensilberkerze, Actaea/Cimicifuga racemosa, Brustkrebszelllinie, Triterpenglykoside, Zimtsaureester Induction of Apoptosis by Triterpene Glycosides and Cinnamic Acid Esters from an Isopropanolic Extract of Black Cohosh in Human MCF-7 Breast Cancer Cells. An isopropanolic-aqueous extract of black cohosh (iCR) exerts antiproliferative effects on estrogen-receptor positive human breast cancer cells MCF-7 via the induction of apoptosis. Here we tested whether apoptosis induction is attributable to one of the two major fractions of iCR, the triterpene glycosides (TTG) or the cinnamic acid esters (CAE). The antiproliferative activity of TTG and CAE on MCF-7 cells were investigated by WST-1 assay. Apoptosis was detected and quantified by flow cytometry using light scatter characteristics and Annexin V binding. 72 h iCR treatment induced a dose-dependent down regulation of cell proliferation with an IC50 of 55.3 µg/ml dry residue which corresponds to 19.3 µg/ml TTG and 2.7 µg/ml CAE. Both, isolated TTG and CAE fractions inhibited cell growth, the IC 50 being 59.3 µg/ml and 26.1 µg/ml, respectively. Interestingly, whereas IC50 and apoptosis induction correspond well for the whole extract, TTG and CAE fractions induced apoptosis at concentrations (25 and 5 µg/ml) well below those required for significant growth inhibition. Observations in this study firstly showed that TTG and CAE compounds significantly contribute to iCR’s apoptotic effect. Even though CAE is the more potent inhibitor of proliferation and apoptosis inducer, TTG – due to its quantitative predominance – is at least as important as the former for iCR’s net effect. J Menopause 2006; 13 (1): 24–6.

A potential bone-sparing effect of Rhizoma actaeae (=cimicifugae) racemosae (black cohosh) was evaluated in ovariectomized Sprague–Dawley rats. The rats were ovariectomized at 12 weeks of age (body weight, 219–226 g) and placed on a soy-free diet 6 days after surgery. Animals were randomly assigned the following groups: control (n = 10), soy-free diet only; RAL (n = 10), soy-free diet plus raloxifene 3 mg/kg intragastrically; and REM (n = 10), soy-free diet supplemented with an isopropanolic black cohosh extract (Remifemin) with a daily intake of 4500 µg triterpeneglycosides. Urinary levels of pyridinoline (PYR) and deoxypyridinoline (DPY), specific markers for bone loss, were measured at baseline and at weekly intervals. At the end of the study, the animals were killed and bone loss was determined by volumetric bone mineral density (BMD) measurements and peripheral quantitative computed tomography (pQCT). Mechanical resistance to fracture was also determined. Results demonstrated that an isopropanolic extract of black cohosh significantly diminished the urinary content of PYR and DPY and the morphometric correlates of bone loss associated with ovariectomy in rats. Reversal of the effects of ovariectomy on bone loss began 2–5 weeks after the start of treatment and continued through at least 7 weeks. Results similar in quality and magnitude were obtained in the group treated with raloxifene, a known selective estrogen receptor modulator (SERM). Because extracts of black cohosh are already recognized as safe and effective in the treatment of certain gynecological disorders, a longer-term clinical trial of this herbal remedy for the treatment of osteoporosis is warranted.

Hormone replacement therapy, which is a common menopausal treatment, is contraindicated in women with breast cancers due to concerns regarding the potential for breast cell proliferation. As such, there is a need for alternative methods for treating menopausal symptoms. To determine the influence of one such alternative, black cohosh (Cimicifuga racemosa [CR]), on estrogen-dependent mammary cancers, we conducted an in vitro investigation of the effect of an isopropanolic CR-extract on the proliferation of estrogen receptor-positive breast cancer cells. The experiments were performed using the human breast adenocarcinoma (MCF-7) cell test system, an established in vitro model for estrogen-dependent tumors. The influence of CR-extract on the proliferation of the MCF-7 cells was determined by measuring the incorporation of radioactively labeled thymidine. Under estrogen-deprived conditions, the CR-extract (10−3–10−5 dilutions) significantly inhibited MCF-7 cell proliferation. Additionally, application of the CR-extract inhibited estrogen-induced proliferation of MCF-7 cells. Moreover, the proliferation-inhibiting effect of tamoxifen was enhanced by the CR-extract. Such data that suggest a non-estrogenic, or estrogen-antagonistic effect of CR on human breast cancer cells lead to the conclusion that CR treatment may be a safe, natural remedy for menopausal symptoms in breast cancer.

Echinacea extracts are widely used in European countries and in the United States as "immune-stimulating" agents. Even though the evidence to stimulate certain components of the nonspecific immune system (phagocytosis, macrophages, and production of cytokines) stems from in vitro experiments or studies after parenteral application, the commercially available Echinacea preparations used as drugs or supplements are for oral use. The aim of the study was to determine whether phagocytic activity and production of cytokines is stimulated by oral application of a commercially available Echinacea preparation. Forty healthy male volunteers (ages 20-40 years) participated in the study. They received either a freshly expressed juice of Echinacea purpurea herbs or placebo juice using a double-blind placebo-controlled crossover design with two treatment periods of 14 days and a wash-out period of 4 weeks in between. Endpoints for immune stimulation: phagocytic activity of polymorphonuclear leukocytes and monocytes measured by flowcytometry, production of tumor necrosis factor alpha (TNF)-alpha and Interleukin (IL)-1beta by LPS-stimulated blood monocytes. Echinacea purpurea herbs did neither enhance phagocytic activity of polymorphonuclear leukocytes nor that of monocytes when compared with placebo. Echinacea purpurea herbs did not influence the production TNF-alpha and IL-1beta by LPS-stimulated monocytes. Unexpectedly, Echinacea purpurea herbs decreased serum ferritin concentration (p = 0.0005). All other laboratory and safety data remained unchanged. The "immune stimulation" by Echinacea purpurea observed in vitro and after parenteral administration are not confirmed in healthy humans after oral intake. Other immunomodulatory effects may explain the benefits of Echinacea preparations in reducing duration and severity of upper-respiratory tract infections found in randomized, double-blind clinical trials.