121 The Influence of Food Formulation on Digestive Behavior and Bioavailability of Catechin Polyphenols M.G. Ferruzzi 1,2 , R.J. Green 1 , C.M. Peters 2 , A.P. Neilson 1 and E.M. Janle 2 1 Department of Food Science and 2 Department of Foods and Nutrition Purdue University, West Lafayette, IN USA Keywords: catechins, tea, in vitro digestion, Caco-2, digestive stability, plasma pharmacokinetics, bioavailability Abstract Consumption of catechin rich foods is associated with a reduction of chronic disease risks. While promising, poor oral bioavailability of catechins from foods is believed to minimize the potential efficacy of these polyphenols. Many factors are believed to contribute to poor catechin bioavailability including: digestive instability, poor intestinal transport, and rapid metabolism and clearance. In order to better understand how food formulation influences catechin bioavailability, both in vitro and in vivo techniques were applied to pure catechins and tea model systems to investigate specific aspects of human digestion and intestinal absorption. Extracts were formulated with common adjuncts including: fruit juices, creamers and food grade antioxidants. Model beverages were subjected to a two stage in vitro digestion coupled to a Caco-2 culture model to determine digestive stability and accumulation/transport by human intestinal cells. Concurrently, in vivo catechin bioavailability was investigated in a Sprague Dawley rat model. Exposure of catechins to simulated digestive conditions resulted in significant loss of epigallocatechin (EGC) (91%), epigallocatechin-gallate (EGCG) (72%) and epicatechin-gallate (ECG) (60%), compared to epicatechin (EC) (11%) and catechin (C) (7%). Homo- and hetero-dimers of EGCG and EGC were characterized in simulated intestinal juices by LC-MS/MS as digestive products. Addition of ascorbic acid (0.25 mg/mL) and citrus juices (20% (v/v)) were found to enhance digestive recovery of native EGCG (20 to > 70%) and EGC (5 to > 90%). Accumulation of catechins by Caco-2 human intestinal cells was also enhanced by formulation with ascorbic acid and citrus juices primarily due to improved digestive recovery and increased uptake efficiency. Ongoing animal studies suggest that in vivo bioavailability of digestively labile catechins, EGCG and EGC, may be improved by formulation with ascorbic acid relative to controls. These data provide evidence that formulation factors impact digestive recovery and may influence intestinal absorption of catechins in vivo. INTRODUCTION Catechins, present in many fruits, vegetables and tea (Camellia sinensis), have been linked by epidemiological studies to the prevention of several chronic diseases including cancer and cardiovascular disorders (Scalbert et al., 2005; Nichenametla et al., 2006). Interest in tea catechins (Fig. 1a) as a potential physiologically active agents has intensified due to their abundance in brewed tea, and their documented biological activities (Higdon and Frei, 2003). While catechins hold significant promise as health promoting compounds, their eventual significance may be limited by their limited oral bioavailability (< 2%) (Feng, 2006), and evidence suggests that instability of tea catechins to digestive conditions may contribute, in part, to this reduced bioavailability (Record and Lane, 2001; Green et al., 2007). Instability of catechins to small intestinal conditions (pH > 6) has been documented (Zhu et al., 1997; Yoshino et al., 1999; Green et al., 2007). Additionally, absorption of catechins may be limited by apical ABC transporters such as P-glycoprotein and Multidrug Resistance Proteins that serve to reduce the effective transepithelial transport of native catechins from tea (Vaidyanathan and Walle, 2003). Proc. II nd IS on Human Health Effects of F&V Ed.: B. Patil Acta Hort. 841, ISHS 2009