1. Department of Organic Chemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
2. Department of Chemistry, Higher Teacher Training College, University of Yaoundé 1, Yaoundé, Cameroon
3. Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
4. Department of Process Engineering, National Polytechnique School, University of Douala, Douala, Cameroon
5. Department of Chemistry, Faculty of Science, The University of Bamenda, Bambili, Cameroon
6. Department of Biology, Higher Teacher Training College, University of Yaoundé 1, Yaoundé, Cameroon
7. Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, Bielefeld, Germany