1. Department of Organic Chemistry, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
2. Section of Organic Chemistry, Department of Chemistry, Faculty of Science, Ege University, 35500 Bornova-Izmir, Turkey
3. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
4. Department of Pharmaceutical Sciences and Traditional Pharmacopeia, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, P.O. Box 8664, Yaoundé, Cameroon