Botanical Products Act like Estrogen in Animals, Finds University of Pittsburgh Team
PITTSBURGH, April 11, 1999 — A University of Pittsburgh and Pittsburgh VA Medical Center team has provided new evidence that certain botanical products act like estrogen in animals. The findings indicate how these agents may work to relieve menopausal symptoms but suggest their potential danger for women who should not take estrogen.
The scientists are reporting their findings April 11 at the annual meeting of the American Association for Cancer Research in Philadelphia.
"Of the plant products we examined, we found that vitex, dang gui, American ginseng and cohosh produced estrogen-like effects in animals," remarked Patricia Eagon, Ph.D., associate professor of medicine at the University of Pittsburgh and principal investigator on the study. "These findings confirm reports that these plants relieve menopausal symptoms, especially hot flashes. However, we still need to conduct further pre-clinical tests with these substances to study their long-term effects and to ensure that they are safe to use."
"Our results should signal a strong note of caution to women who want to relieve menopausal symptoms but who have a family or personal history of breast or uterine cancer," added Dr. Eagon. Estrogen is known to fuel the growth of these cancers.
Because the U.S. Food and Drug Administration does not regulate these botanical products, many women who should not take them could end up using them, remarked Dr. Eagon. Moreover, overuse of these remedies or impurities in the products can lead to liver problems and blood clotting disorders, she added.
The Pittsburgh research team found that extracts of vitex, dang gui, American ginseng and cohosh bound directly to estrogen receptors, just as natural estrogen would. The investigators next tested these compounds in rats whose ovaries were removed so they could not produce significant levels of natural estrogen. After 30 days of treatment, the researchers found that the uterus in each rat grew heavier, an indication that this organ had an estrogen-like response to the extracts. In addition, the scientists found that blood levels of luteinizing hormone (LH) decreased in these animals. Produced by the pituitary, LH triggers other organs to make estrogen. Naturally high levels of estrogen turn off LH production. In the treated animals, the plant extracts similarly reduced LH production, according to the investigators.
"It appears as though these extracts work through several biological pathways," added Dr. Eagon.
Herbal remedies have been used for centuries to relieve various gynecological symptoms, including absent periods, painful periods and symptoms of menopause. Vitex, or chaste berry, is a Mediterranean plant traditionally used to relieve menopausal symptoms. Dang gui and ginseng are traditional Chinese remedies for a variety of gynecological problems. Cohosh is a traditional American Indian cure for menstrual pain and menopausal discomfort. Black cohosh has been shown to relieve hot flashes in European clinical trials.
Dr. Eagon’s research is supported by a breast cancer research grant from the U.S. Army.