1. Chemistry Laboratory, Department of Chemistry, Faculty of Science, University of Douala, Douala, Cameroon
2. Department of Organic Chemistry, University of Yaounde 1, Yaounde, Cameroon
3. Department of Chemistry, University of Buea, Faculty of Sciences, Buea, Cameroon
4. University Institute of Technology, University of Ngaoundere, Ngaoundere, Cameroon
5. Department of Chemical Sciences, Faculty of Science, Pen Resource University, Gombe, Nigeria
6. Department of Chemical Sciences, Faculty of Science, Federal University of Kashere, Gombe, Nigeria
7. Royal Botanic Gardens Kew, Richmond, UK