1. Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, Department of Human Nutrition and Epidemiology, Wageningen University, P.O.B. 8129, 6700 EV Wageningen, The Netherlands, and Department of Gastroenterology, University Medical Centre, Nijmegen, The Netherlands