ABSTRACT
The stilbene resveratrol (3,5,4′-trihydroxy-stilbene) is a secondary metabolite with a C6-C2-C6 structure that in planta is a phytoallexin produced in response to disease, injury, and stress (Langcake and Price 1977; Chong et al. 2009). It occurs as both the cis and trans isomers, and the main dietary sources are grapes red wines, peanuts (Arachis hypogaea), and to a lesser extent, berries, red cabbage (Brassica oleacea), spinach (Spinaceae oleacea), pistachio nuts (Pistacia vera L.), and certain herbs. Stilbenes occur in a variety of forms with cis-and trans-resveratrol-3-Oglucosides, commonly known as cis-and trans-piceid, being the major stilbenes in grapes and wines (Stervbo et al. 2007). Brazilian red wines have also been shown to contain trans-piceatannol (3,3′,4,5′-tetrahydroxystilbene) and its 3-O-glucoside trans-astringin (Vitrac et al. 2005). Trans-resveratrol is transformed by Botrytis cinerea, a fungal grapevine pathogen, to pallidol and resveratrol trans-dehydrodimer,
8.1 Sources of Dietary Resveratrol ..................................................................... 167 8.1.1 Grapes and Wines ............................................................................. 168 8.1.2 Peanuts .............................................................................................. 169 8.1.3 Berries ............................................................................................... 170 8.1.4 Tomatoes ........................................................................................... 170 8.1.5 Cocoa-Based Products ...................................................................... 170 8.1.6 Hops and Beer................................................................................... 171 8.1.7 Japanese Knotweed ........................................................................... 171 8.1.8 Dietary intake of Resveratrol ............................................................ 171
8.2 Bioavailability and Metabolism of Resveratrol ............................................ 172 8.2.1 In Vitro Studies and Animal Models ................................................ 172 8.2.2 Human Studies .................................................................................. 173 8.2.3 Factors Inuencing Trans-Resveratrol Metabolism In Vivo ............. 176 8.2.4 Summary of Resveratrol Absorption and Metabolism ..................... 177
References .............................................................................................................. 179
and both these compounds have been detected in grape cell cultures along with the 11-O-and 11′-O-glucosides of resveratrol trans-dehydrodimer (Waffo-Teguo et al. 2001). Viniferins are another family of oxidized resveratrol dimers (Langcake and Pryce 1977), and δ-viniferin and smaller amounts of its isomer ε-viniferin have been detected in Vitis vinifera leaves infected with Plasmopara viticola (downy mildew) (Pezet et al. 2003). Structures of these stilbene are illustrated in Figure 8.1. For further information on the structural diversity of naturally occurring stilbenes, interested readers should consult Shen et al. (2009).
