ABSTRACT
Polyphenols are a diverse group of phytochemicals that include many of the molecules that give fruits and vegetables their colors. They are characterized structurally by the presence of multiple phenol rings and have numerous functions, ranging from ultraviolet (UV) shielding to pathogen resistance (Winkel-Shirley 2002). Polyphenols are also the major source of antioxidant activity in plant-derived foods, a fact that is often overlooked in favor of the more familiar antioxidant vitamins (Halliwell 2007). Recently, polyphenols have been thrust into the spotlight, due in part to the apparent health benets of resveratrol, a relatively uncommon member of this class found in wine, berries, and traditional medicines (Figure 9.1). At least in rodents, resveratrol prevents cancer, increases endurance, and ameliorates many of the consequences of obesity, including the loss of insulin sensitivity and increase in mortality rate, albeit at doses in excess of what could be obtained from dietary sources (Jang et al. 1997; Baur et al. 2006; Lagouge et al. 2006). Although these results have garnered much attention, resveratrol is far from the only member of this class of molecules to exert benecial effects on mammalian health. For example, many of the benets of green tea have been attributed to the polyphenol epigallocatechin gallate (EGCG), pterostilbene in blueberries may have anticancer and anti-inammatory effects, and a number a foods thought to promote health, including wine, contain the polyphenol quercetin, which has independent benets and may synergize with resveratrol (Mertens-Talcott and Percival 2005). More than 8000 distinct polyphenols have been described (Bravo 1998), and in most cases almost nothing is known about these molecules. Nevertheless, a handful of specic polyphenols, including resveratrol, have been studied in some detail and may provide clues as to how these molecules interact with mammalian biology.
