This project was conducted to investigate the antimicrobial properties and to record the essential oil profiles of a selection of species belonging to the genus Agathosma. Plants have been used for many years by the local South Africans to treat various infections and illnesses. This knowledge has largely been untapped. Buchu is one of the plant species that are used extensively by the San and Koi people. It is remarkable that of the ca. 150 Agathosma species indigenous to South Africa (Goldblatt and Manning 2000) only two species (Agathosma crenulata and Agathosma betulina) have been investigated for biological activity (van Wyk and Gericke, 2000). The genus Agathosma is traditionally used for the following conditions; stomach ailments, fever, coughs, colds, flu, urinary and kidney infections, haematuria, prostatitis, rheumatism, gout, bruises and for antiseptic purposes (Watt and Breyer-Brandwijk,
1962). The antimicrobial activity and leaf essential oil chemistry were investigated for A. arida, A. capensis, A. lanata, A. mundtii, A. ovalifolia, A. ovata, A. recurvifolia, A. serpyllaceae and A. zwartbergensis. The phytochemistry of the essential oils was analyzed by using gas chromatograph-mass spectroscopy. The antimicrobial properties were analyzed by using disc diffusion assays, MIC/microplate assays and TLC bioautographic assays.
All the species showed some degree of antimicrobial activity. The minimum
inhibitory concentrations of A. capensis, A. ovata and A. recurvifolia were
determined. A TLC bioautographic assay for A. zwartbergensis indicated that
citronellal could be a responsible for the antimicrobial activity.
Principal supervisor: Prof AM Viljoen
Co-supervisor: Dr SF van Vuuren (WITS)