1. Department of Chemistry, Higher Teachers’ Training College, University of Maroua, Maroua, Cameroon
2. Section of Pharmacognosy, Institute of Natural Medicine, University of Toyama, Toyama, Japan
3. Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
4. Department of Chemistry, Faculty of Sciences, National University of Burundi, Bujumbura, Burundi