1. The University of Mississippi, School of Pharmacy, Research Institute of Pharmaceutical Science and Department of Pharmacognosy, National Center for Natural Products Research, MS 38677
2. University of the Western Cape, Department of Chemistry, Private Bag X17, Bellville 7535, South Africa
3. University of Missouri-Columbia, Division of Plant Sciences, 215 Curtis Hall, Columbia, MO 65211-7020
4. University of the Western Cape, Department of Biodiversity & Conservation Biology, Private Bag X17, Bellville 7535, South Africa