1. Molecular Biology Section, Department of Biology, Faculty of Science, University of Istanbul, 34459 Vezneciler-Istanbul, Turkey, TUBITAK, Marmara Research Center, Materials and Chemical Technologies Research Institute, Department of Chemistry, P.O. Box 21, 41470 Gebze-Kocaeli, Turkey, and Program for Collaborative Research in the Pharmaceutical Sciences, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Ilinois 60612