1. Department of Chemistry, Higher Teachers Training College, University of Yaoundé I, Yaoundé, Cameroon
2. Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
3. Faculty of Natural and agricultural sciences, Department of Chemistry, University of the Free State, Bloemfontein, South Africa
4. Centre de Recherche en Plantes Médicinales et Médecine Traditionnelle (CRPMT), IMPM, Yaoundé, Cameroon