1. Natural Products Chemistry Research Unit Chemistry Department Faculty of Science University of Dschang P.O. Box 67 Dschang Cameroon
2. Research Unit of Microbiology and Antimicrobial Substances Biochemistry Department Faculty of Science University of Dschang Dschang Cameroon
3. Department of Bioorganic Chemistry Leibniz Institute for Plant Biochemistry D-06120 Halle (Saale) Germany
4. Institute of Pharmaceutical Biology Technische Universität Braunschweig D-38106 Braunschweig Germany