1. Department of Medicinal Chemistry and Pharmacognosy, Program for Collaborative Research in the Pharmaceutical Sciences, UIC/NIH Center for Botanical Dietary Supplements Research, College of Pharmacy, M/C 781, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, and Department of Mathematics, Statistics, and Computer Science, University of Illinois at Chicago, 851 South Morgan Street, M/C 249, Chicago, Illinois 60607