August 2004 - A compound in blueberries shows promise in preliminary laboratory studies of lowering cholesterol as effectively as a commercial drug and has the potential for fewer side effects, according to a researcher with the U.S. Department of Agriculture.
The compound, pterostilbene, has the potential to be developed into a nutraceutical for lowering cholesterol, particularly for those who don't respond well to conventional drugs used for this purpose, the researcher says. Findings were described at the 228th national meeting of the American Chemical Society, the world's largest scientific society.
"We are excited to learn that blueberries, which are already known to be rich in healthy compounds, may also be a potent weapon in the battle against obesity and heart disease, which are leading killers in the U.S.," says study leader Agnes M. Rimando, Ph.D., a research chemist with the USDA's Agricultural Research Service (ARS). She works at the ARS' Natural Products Utilization Research Unit in Oxford, Miss.
Researchers have suspected for some time, based on anecdotal studies, that blueberries may play a role in lowering cholesterol, says Rimando.
Pterostilbene is an antioxidant that is similar to resveratrol, another antioxidant identified in grapes and red wine that is also believed to lower cholesterol. Other researchers have found pterostilbene in grapes, but this is the first time it has been found in blueberries, says Rimando. She and her associates earlier showed that this compound may help fight cancer. Pterostilbene has been reported previously by others to have anti-diabetic properties as well.
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In this new laboratory study using rat liver cells, Rimando and her collaborators, Rangaswami Nagmani and Dennis Feller, of the University of Mississippi's School of Pharmacy, exposed the cells to four other compounds found in blueberries. Of the four compounds, pterostilbene showed the highest potency for activating the cells' PPAR-alpha receptor, which in turn plays a role in reducing cholesterol and other lipids.
Pterostilbene was similar in activity to ciprofibrate, a commercial drug that lowers LDL (bad) cholesterol and triglycerides. But ciprofibrate, whose mechanism of action on cells is less specific, can have side effects such as muscle pain and nausea. Pterostilbene, which targets a specific receptor, is likely to have fewer side effects, Rimando says, adding that the compound did not show any signs of cell toxicity in preliminary studies.
Until studies are conducted in humans, no one knows how many blueberries a person needs to eat to have a positive effect at lowering cholesterol, Rimando cautions. Her study adds to a growing list of health benefits attributed to the little antioxidant-rich fruit, including protection against aging, heart disease and cancer, as well as acting as a memory booster.
Agnes M. Rimando, Ph.D., is a research chemist with the USDA's Agricultural Research Service. She works at the ARS' Natural Products Utilization Unit in Oxford, Miss. Rangaswamy Nagmani, Ph.D., and Dennis R. Feller, Ph.D., of the University of Mississippi School of Pharmacy in University, Miss., are collaborators of Dr. Rimando on this project.
Source: American Chemical Society