1. Department of Chemistry, Higher Teacher Training College, University of Yaounde I, Yaounde P.O. Box 47, Cameroon
2. Department of Organic Chemistry, Faculty of Science, University of Yaounde I, Yaounde P.O. Box 812, Cameroon
3. Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, D-33501 Bielefeld, Germany
4. Department of Chemistry, University of Dschang, Dschang P.O. Box 67, Cameroon
5. Department of Biology, Higher Teacher Training College, University of Yaounde I, Yaounde P.O. Box 47, Cameroon
6. Molecular Biology Center, Yaounde P.O. Box 14495, Cameroon