Mechanism of black cohosh versus hot flashes revealed

Dec 21, 2006

The natural herb black cohosh is commonly used by women to treat menopausal symptoms such as hot flashes, but the molecular mechanisms underlying its action have eluded scientists -- until now.

Researchers at the University of Illinois at Chicago and the National Institutes of Health Center for Botanical Dietary Supplements Research have discovered that black cohosh may act on human opiate receptors, which play a role in regulating a body's temperature.

Z. Jim Wang, assistant professor of pharmacology and pharmaceutics, led the study, which will be published in an upcoming issue of the Journal of Agricultural and Food Chemistry; the paper is currently available on the journal's web site.

Opiate receptors are chemical sensors that respond to opiates like morphine and endorphins, Wang said. Chemical substances with opiate activity bind to the receptors and produce the appropriate response, including the regulation of pain, temperature and appetite.

"We used several extracts of black cohosh and found that elements of the herb could bind to the human 'mu' opiate receptor," Wang said. "The opiate receptor system affects several aspects of female reproductive neuroendocrinology, such as the levels of sex hormones and neurotransmitters that are important for temperature regulation."

Black cohosh (known as both Actaea racemosa and Cimicifuga racemosa) is a member of the buttercup family. A perennial plant, it is native to North America. It has been used by Native Americans to treat malaise, gynecological disorders, kidney ailments, malaria, rheumatism and sore throat, as well as colds, cough, constipation, hives and backaches, and to induce lactation.

Women experience a variety of symptoms of menopause, but the hot flash is the most common. Although the exact mechanism of the hot flash is unclear, estrogen withdrawal during menopause clearly plays an important role, Wang said. It is assumed that declining estrogen concentrations may change the levels of brain chemicals called neurotransmitters.

As a result, the thermoregulatory center located in the hypothalamus functions irregularly, which leads to inappropriate peripheral vasodilatation that causes hot flashes.

"The hypothalamic thermostat setting can be controlled directly or indirectly by the opiate system," Wang said.

Wang said this is the first time black cohosh has been linked to the activity of the opiate receptors. The ethanol extract used in this study, he said, is currently being used in a phase II clinical trial conducted by researchers from the UIC/NIH Center for Botanical Dietary Supplements Research.

Source: University of Illinois at Chicago

Explore further: Brazil finds coffee protein with morphine effect

add to favorites email to friend print save as pdf

Related Stories

Obama recommends extended wilderness zone in Alaska

9 hours ago

US President Barack Obama said Sunday he would recommend a large swath of Alaska be designated as wilderness, the highest level of federal protection, in a move likely to anger oil proponents.

NASA craft set to beam home close-ups of Pluto

9 hours ago

Nine years after leaving Earth, the New Horizons spacecraft is at last drawing close to Pluto and on Sunday was expected to start shooting photographs of the dwarf planet.

Navy wants to increase use of sonar-emitting buoys

10 hours ago

The U.S. Navy is seeking permits to expand sonar and other training exercises off the Pacific Coast, a proposal raising concerns from animal advocates who say that more sonar-emitting buoys would harm whales and other creatures ...

Uganda seizes massive ivory and pangolin haul

11 hours ago

Ugandan wildlife officers have seized a huge haul of elephant ivory and pangolin scales, representing the deaths of hundreds of endangered animals, police said Sunday.

Recommended for you

Cochlear implant users can hear, feel the beat in music

11 hours ago

People who use cochlear implants for profound hearing loss do respond to certain aspects of music, contrary to common beliefs and limited scientific research, says a research team headed by an investigator at Georgetown University ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.