Seeds from South African plants as a source of bioactive metabolites
South Africa has a rich diversity of plant species which contain various classes of bioactive compounds . Seeds of these plants have been little studied from a chemical viewpoint and a survey of their constituents is of high interest. The source plants of these seeds may grow in areas with extreme climatic conditions, thus increasing the chances of finding original metabolites.
Seeds from plants (mainly trees) growing in different areas of South Africa were extracted with methanol and screened for radical scavenging activity in a TLC assay with the 2,2-diphenyl-1-picrylhydrazyl radical. Inhibition of acetylcholinesterase by TLC bioautography  was also performed, as compounds which inhibit this enzyme may have some application in the management of Alzheimer's disease. The extracts were also screened for antimicrobial and antimalarial activities.
Two species were selected for further study: Schotia brachyphylla Sond. (Fabaceae) and Colophospermum mopane (J. Kirk ex Benth.) J. Kirk ex J. Leonard (Fabaceae). The bioactive constituents of the seeds, including two new 4-coumaroyl derivatives of flavonoids (1, 2), were isolated by a combination of high-speed countercurrent chromatography and classical chromatographic techniques.
References: 1. Mulholland DA and Drewes SE (2004) Phytochemistry 65: 769–782.
2. Marston A, Kissling J and Hostettmann K (2002) Phytochemical Analysis 31: 51–54.