1. Institut für Pharmazeutische Biologie und Biotechnologie, Heinrich-Heine-Universität, Universitätsstraße 1, Geb. 26.23, D-40225 Düsseldorf, Germany
2. Permanent address: Department of Pharmacognosy, Faculty of Pharmacy, Khartoum Sq. Azarita, Alexandria, Egypt
3. Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, The John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR, Scotland, UK
4. Helmholtz Centre for Infection Research, Inhoffenstraße 7, D-38124 Braunschweig, Germany
5. Institut für Physiologische Chemie und Pathobiochemie, Johannes-Gutenberg-Universität, Duesbergweg 6, D-55128 Mainz, Germany
6. State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, People’s Republic of China
7. Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen AB24 3UE, Scotland, UK.