1. Department of Chemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon
2. Organic and Bioorganic Chemistry, Faculty of Chemistry, University of Bielefeld, D-33501 Bielefeld, Germany
3. Department of Chemistry, Higher Teacher Training College, University of Yaoundé I, P.O. Box 47, Yaoundé, Cameroon
4. Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, P.O.
Box 812, Yaoundé, Cameroon
5. Department of Chemistry, Faculty of Science, The University of Bamenda, P.O. Box 39, Bambili, Cameroon
6. Department of Biology, Higher Teacher Training College, University of Yaoundé I, P.O.
Box 47, Yaoundé, Cameroon