1. Natural Products Chemistry Research Unit, Faculty of Science, University of Dschang, Dschang, Cameroon
2. Research Unit of Microbiology and Antimicrobial Substances, Faculty of Science, University of Dschang, Dschang, Cameroon
3. Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, Bielefeld, Germany
4. Department of Chemistry, Higher Teacher Training College, University of Yaounde I, Yaounde, Cameroon