1. Department of Chemistry, Faculty of Science, Rhodes University, Makhanda 6140, South Africa
2. Department of Pharmaceutical Sciences, School of Pharmacy, Sefako Makgatho Health Sciences University, Box 218, MEDUNSA, Pretoria, 0204, South Africa
3. Departments of Biochemistry and Microbiology, Faculty of Science, Rhodes University,
Makhanda 6140, South Africa
4. Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, P. O Box 35061, Dar es Salaam, Tanzania
5. Center for Chemical and Biomedicinal Research (CCBR), Rhodes University, South Africa