1. Laboratory of Pharmacognosy, Institute of Pharmacy, University of Liège, CHU, Tour 4, Avenue de l'Hôpital 1, B-4000 Liège, Belgium, Laboratory of Medical Microbiology, University of Liège, CHU, Tour 3, Avenue de l'Hôpital 1, B 4000 Liège, Belgium, Laboratory of Histology and Cytology (Centre de Recherche en Cancérologie Expérimentale), Institute of Anatomy, University of Liège, Liège, Belgium, and Laboratory of NMR, Institute of Physics, University of Liège, Sart Tilman, B 4000 Liège, Belgium