1. Institute of Organic Chemistry
2. University of Würzburg
3. D-97074 Würzburg
4. Germany
5. Faculté des Sciences Pharmaceutiques
6. Faculté des Sciences
7. Université de Kinshasa
8. Democratic Republic of the Congo
9. Swiss Tropical and Public Health Institute
10. CH-4002 Basel
11. Switzerland
12. University of Basel
13. CH-4003 Basel