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For the first time, researchers have identified a particular polyphenol and its metabolites in human low-density lipoproteins (LDL) after moderate consumption of red wine. Polyphenols in red wine have been shown to protect the heart from atherosclerosis, but it is unclear exactly which ones are responsible for the beneficial effects. As described in the May 15 issue of Analytical Chemistry (pp 3149–3155), Cristina Andres-Lacueva, doctoral student Mireia Urpí-Sardà, and colleagues at the University of Barcelona, the Institute of Medical Investigation (both in Spain), and the University of Vienna (Austria) have developed a new LC/ESIMS/MS method that can detect the polyphenol resveratrol in human LDL at levels down to 0.15 pmol/mL. Resveratrol has been shown to inhibit the oxidation of LDL in vitro. High levels of oxidized LDL are a hallmark of heart disease. Some in vitro studies have investigated the antioxidant capabilities of polyphenols in red wine, but no one has described which polyphenols bind to LDL in vivo, says Andres-Lacueva. Using their new method, the researchers measured the amounts of resveratrol and several of its metabolites in human LDL after intake of 250 mL of Merlot. They chose that particular variety of wine because it is known
to have the highest levels of resveratrol. Human volunteers were put on a special diet, which limited foods that are high in antioxidants, for one week. They were then put on a strict diet, which excluded high-phenolic foods, such as coffee, tea, fruit, vegetables, peanuts, soy, wine, grape juice, and olive oil, for an additional three days. At the end of the 10-day period, a baseline blood sample was taken, and the subjects were given a single 250-mL dose of red wine. After 24 h, another blood sample was taken. In most of the 24-h LDL samples, the researchers detected the metabolites transresveratrol-3-O-glucuronide, cis-resveratrol-3-O-glucuronide, and cis-resveratrol3-O-glucoside, as well as free trans-resveratrol. The concentrations of all the compounds varied between individuals. “This variability between individuals is important because not everybody absorbs polyphenols the same way,” says AndresLacueva. She and her colleagues are currently trying to determine why such variability exists. One hypothesis is that individuals have different polymorphisms of intestinal enzymes or transporters that can affect phenolic absorption. Red wine contains hundreds of polyphenols, and resveratrol may not be the only one with beneficial effects. After absorption there are many metabolites, so it is important to study not just the polyphenols themselves, but how they arrive
to plasma or tissues, says Urpí-Sardà. We may never fully understand what makes moderate amounts of red wine good for the heart, but as analytical methods become more sensitive, researchers are starting to unravel some of the mystery. Vitamin E and beta-carotene in food have been shown to protect the heart by binding to LDL, and now it is clear that resveratrol in red wine does the same thing. So sit back, relax, and have a glass of red wine. a —Britt E. Erickson
plied the most sophisticated MS techniques to characterize these materials because they do not readily form gas-phase ions. He has contributed widely to both the MS and biological communities by providing new tools, methods, and creativity. Gary J. Van Berkel of Oak Ridge National Laboratory will receive the 2005 Biemann Medal, which recognizes achievements in MS made by
an individual early in his or her career. Van Berkel was selected for his contributions to the elucidation of the electrochemical aspects of ESI. By combining electrochemistry and MS, he has advanced technology in several areas, including electrochemically modulated separations, the design of ESI tips, inductively coupled plasma MS, and miniaturized analysis. Both awards will be presented in early June at the ASMS annual conference in San Antonio, Texas.
PHOTODISC
Drink to your health
Thanks to more sensitive analytical methods, researchers are one step closer to understanding how polyphenols in red wine protect the heart.
PEOPLE ASMS awards James A. McCloskey, a professor at the University of Utah, will receive the American Society of Mass Spectrometry (ASMS) 2005 Award for a Distinguished Contribution in Mass Spectrometry. McCloskey is best known for his work in the analysis of nucleic acids and modified RNA. He has regularly ap212 A
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