Their study is scheduled to appear in the Jan. 26 issue of the American Chemical Society's Journal of Agricultural and Food Chemistry, one of the Society's peer-reviewed journals. ACS is the world's largest scientific society.
"This is one of a growing number of studies that provide evidence that commonly used natural products really do contain chemicals that may be of medicinal value," says study leader Elaine Holmes, Ph.D., a chemist with Imperial College London. "The healthcare industry is placing increasing emphasis on functional foods including natural remedies, yet little work has been conducted on the long term effects of such products on human biology."
The herbal plant used in this study was German chamomile (Matricaria recutita), also known as manzanilla, whose flowers and leaves are brewed as a fragrant, flavorful tea. The study involved fourteen volunteers (seven women and seven men) who each drank five cups of the herbal tea daily for two consecutive weeks. Daily urine samples were taken and tested throughout the study, both before and after drinking chamomile tea.
The researchers found that drinking the tea was associated with a significant increase in urinary levels of hippurate, a breakdown product of certain plant-based compounds known as phenolics, some of which have been associated with increased antibacterial activity. This could help explain why the tea appears to boost the immune system and fight infections associated with colds, according to the researchers.
Drinking the tea also was associated with an increase in urinary levels of glycine, an amino acid that has been shown to relieve muscle spasms. This may explain why the tea appears to be helpful in relieving menstrual cramps in women, probably by relaxing the uterus, say the researchers. Glycine also is known to act as a nerve relaxant, which may also explain why the tea seems to act as a mild sedative, the scientists note. Glycine supplements are sold in stores for that purpose, they add.
Levels of both hippurate and glycine remained elevated for up to two weeks after the study participants stopped drinking the tea, indicating that the compounds may remain active for quite some time, according to the researchers. Additional studies are needed before a more definitive link between the tea and its alleged health benefits can be established, they emphasize. Funding for this study was provided by Oxford Natural Products, a pharmaceutical, nutraceutical and technology company located in Oxford, England.
The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with a multidisciplinary membership of more than 159,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
-- Mark T. Sampson
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