1. Department of Chemistry, Faculty of Science, University of Dschang, Dschang P.O. Box 67, Cameroon
2. Department of Chemistry, Inorganic and Structural Chemistry, Bielefeld University, P.O. Box 100131, 33501 Bielefeld, Germany
3. Centre Pasteur du Cameroun, Yaounde P.O. Box 1274, Cameroon
4. Department of Biology, Higher Teacher Training College, University of Yaoundé 1, Yaoundé P.O. Box 47, Cameroon
5. Molecular Biology Center, Yaoundé P.O. Box 14475, Cameroon
6. Department of Chemistry, Higher Teacher Training College, University of Yaoundé 1, Yaoundé P.O. Box 47, Cameroon
7. Department of Chemistry, Organic and Bioorganic Chemistry-OC3, Bielefeld University, P.O. Box 100131, 33501 Bielefeld, Germany