1. Department of Chemistry, University of Nairobi, Nairobi, Kenya
2. Institut für Chemie, Universität Potsdam, Potsdam, Germany
3. United States Army Medical Research Directorate-Kenya (USAMRD-K), Kenya Medical Research Institute (KEMRI)/Walter Reed Project (WRP), Kisumu, Kenya
4. Centre for Traditional Medicine and Drug Research, Kenya Medical Research Institute, Nairobi, Kenya
5. Department of Pharmacology and Pharmacognosy, University of Nairobi, Nairobi, Kenya
6. Department of Medical Laboratory Sciences, Masinde Muliro University of Sciences and Technology, Kakamega, Kenya