1. Department of Pharmacognosy, Faculty of Pharmacy, Hacettepe University, TR-06100 Ankara, Turkey, Department of Biology, Faculty of Science, Hacettepe University, TR-06532 Ankara, Turkey, Institute of Organic Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Centre for Pharmacy and Phytotherapy, School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom