1. Department of Organic Chemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
2. Department of Organic Chemistry, Faculty of Science, University of Douala I, Douala, Cameroon
3. Department of Biochemistry, Faculty of Science, The University of Yaoundé I, Yaoundé, Cameroon
4. Department of Chemistry and Physics Southeastern, Louisiana University SLU 10878, Hammond, LA 70402, USA
5. Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, Bielefeld D-33501, Germany
6. Department of Chemistry, Higher Teacher Training College, University of Yaounde I, Yaounde, Cameroon