Past and present postgraduate students

| DTech | 2009 in progress
A biosystematic study of commercially important Sceletium species.

The increasing demand for Sceletium products has led to increased collection from the wild and establishment of commercial plantations of the plant in order to cope with consumer needs. Positive identification of the different species in the Sceletium species complex is not clear as reflected by the use of the same names to refer to different species and the undifferentiated use of the taxa by different communities. There is lack of standard methods based on both primary and secondary metabolites and also at genetic level to determine the authenticity of the different Sceletium species as well as raw material and products. It is therefore necessary to conduct a biosystematic investigation of the genus to provide better understanding of the specific differences between the eight Sceletium species. This will help to resolve the taxonomic delimitations of this species.


The main objective of the study is to develop an efficient protocol to assist in the delimitation of the Sceletium species complex.

The specific objectives of the study are to:
•    Investigate the chemical profiles of eight Sceletium species using Fourier transform infrared spectroscopy (FTIR), high performance thin layer chromatography (HPTLC), HPLC, capillary electrophoresis (CE) and GC-MS.
•    Observe the morphological differences between the different Sceletium species.
•    Investigate both inter- and intraspecific genetic differences between the eight Sceletium species.
•    Isolate alkaloids from Sceletium species.
•    Elucidate the structures of isolated compounds.
•    Determine interspecies variations of alkaloids in the eight Sceletium species.
•    Determine intraspecies variations of alkaloids from within and between S. tortuosum populations.
•    Determine seasonal variations of the alkaloids in S. tortuosum.
•    Compare the effect of different methods of processing such as fermentation of Sceletium plant material on alkaloid yield.
•    Conduct stability studies of Sceletium alkaloids in extracts and in dry plant material.

Principal supervisor: Prof AM Viljoen
Co-supervisors: Prof S Combrinck and Dr N Gericke

Sceletium tortuosum | Mesembryanthemaceae | "kougoed" | flower | botanical | photo: N Gericke - South Africa [2007 ©]