1. National Museum, P.O. Box 266, Bloemfontein 9300, South Africa
2. Department
of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
3. Department
of Biomolecular Sciences, Division of Pharmacognosy, and Research
Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, Mississippi 38677-1848, United States