1. Research Unit of Environmental and Applied Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
2. Department of Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany
3. Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
4. Groupe Isolement et Structure, Institut de Chimie Moléculaire de Reims (ICMR), Reims, France