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Phytoestrogen Black Cohosh May Have Potential as a SERM: Presented at ENDO

By Paula Moyer

Special to DG News

SAN FRANCISCO -- June 24, 2002 -- A preparation of the phytoestrogen cimicifuga racemosa (CR), also known as black cohosh, may have potential as a selective estrogen receptor modulator (SERM) in treating some of the symptoms of menopause.

Investigators from the University of Goettingen in Goettingen, Germany, presented these findings at ENDO 2002, the 84^th annual meeting of the Endocrine Society.

They noted that, although extracts of the rhizome of black cohosh have been used traditionally to treat climacteric complaints, little data exist to demonstrate whether these preparations have effects on other postmenopausal concerns, such as osteoporosis and lipid metabolism.

Therefore, they recruited a group of 97 women had been amenorrhoeic for over six months and who had several menopause-related complaints, including more than three hot flushes per day. Among the original group, 35 patients had to be excluded because they had begun menstruation or because their hot flushes decreased to less than three per day. The remaining 62 patients were the assigned to one of three study arms: black cohosh, conjugated oestrogen, or placebo. The study was double-blinded.

The 20 patients in the black cohosh group received 40 mg of a commercially available black cohosh preparation (Klimadynona, Menofema). The 22 patients in the oestrogen group received 0.6 mg conjugated oestrogens. Prior to and at 4 weeks intervals during and after the 3 months trial period, the investigators obtained blood samples from the patients and their self-ratings on the menopause rating scale (MRS).

The subjects' major climacteric complaints were significantly more reduced by both conjugated oestrogens and black cohosh than by placebo (p< 0.05). The serum ratio for bone-specific alkaline phosphatase and crosslaps, as well as that for HDL and LDL, were significantly increased by black cohosh (p< 0.05). The investigators noted that they did not see this effect with conjugated oestrogens for HDL/LDL ratios. The black cohosh preparation had no significant effect on endometrial thickness, which was increased in the conjugated oestrogen group.

"We did notice a large placebo effect on some symptoms, such as hot flushes, but the more anatomic the symptom, the less placebo effect we saw," said lead investigator Wolfgang Wuttke, MD, professor of clinical and experimental endocrinology at the University of Goettingen. For example, less placebo effect was seen regarding vaginal dryness. "We were pleased also to see that this preparation of black cohosh seems to stimulate osteoblasts."

This, he said, was the first double-blind, controlled study to demonstrate black cohosh's efficacy in treating menopause. He stressed that many preparations of black cohosh are isoproponylic, and that the formulation used in the study was an aqueous ethanolic extract. "The way the phytoestrogen is extracted from black cohosh determines whether it has an oestrogenic or anti-oestrogenic effect," Dr. Wuttke said. "For example, isoproponylic extracts have no effect on the vaginal epithelium, but ours promoted vaginal epithelial growth while having a neutral effect on the uterus."

Prior in vitro and animal studies have shown that the study formulation is not active on mammary cells, and therefore may not have breast cancer risks, Dr. Wuttke said.

This black cohosh preparation, known for now as BNO 1055, is manufactured by Bionorica AG, which donated the product for the study. Dr. Wuttke has no proprietary interest in the company.

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