1. Department of Biological Sciences, University of Ngaoundere, Ngaoundere, Cameroon
2. Department of Biological Sciences, University of Bamenda, Bamenda, Cameroon
3. Center for Research on Medicinal Plants and Traditional Medicine (CRPMT), Institute of Medical Research and Medicinal Plants Studies, Yaoundé, Cameroon
4. Julius Kühn-Institut, Institute for Ecological Chemistry, Plant Analysis and Stored Products Protection, Königin-Luise Str.19, Berlin, Germany