1. Department of Pharmacognosy, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences; Kwame Nkrumah University of Science and Technology; Kumasi Ghana
2. Department of Herbal Medicine, Faculty of Pharmacy and Pharmaceutical Sciences; College of Health Sciences, Kwame Nkrumah University of Science and Technology; Kumasi Ghana
3. Natural Product Unit; Novartis Institutes for Biomedical Research; Basel 4056 Switzerland
4. Analytical Sciences; Novartis Institutes for BioMedical Research; Basel 4056 Switzerland
5. Department of Biological and Pharmaceutical Chemistry; UCL School of Pharmacy; 29-39 Brunswick Square London WC1N 1AX UK