1. Department of Chemistry, University of Nairobi, Nairobi, Kenya
2. Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
3. Faculty of Science, Department of Biochemistry, University of Dschang, Dschang, Cameroon
4. Institute of Chemistry, University of Potsdam, Potsdam, Germany
5. Centre for Traditional Medicine and Drug Research, Kenya Medical Research Institute, Nairobi, Kenya