Publications

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Moolla, A., Van Vuuren, S.F., Van Zyl, R.L., Viljoen, A.M. 2007. Biological activity and toxicity profile of 17 Agathosma (Rutaceae) species. South African Journal of Botany, 73: 588–592.

The antimicrobial, anti-oxidant and cytotoxic activities of the extracts obtained from 17 indigenous Agathosma species (19 samples) were investigated in order to validate the historic and continued use of Agathosma species in traditional healing. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method on four pathogens, i.e. Staphylococcus aureus (ATCC 12600), Bacillus cereus (ATCC 11778), Klebsiella pneumoniae (NCTC 9633) and Candida albicans (ATCC 10231). The anti-oxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, while the cytotoxic properties was determined using the MTT (3-[4,5-dimethyl-2-thiazol-yl]-2,5-diphenyl-2H-tetrazolium bromide) cellular viability assay. Agathosma ovata (round-leaf) displayed the best activity against S. aureus and B. cereus with MIC values of 0.16 mg/ml and 0.13 mg/ml, respectively. Most of the extracts had moderate to poor activity in the DPPH assay with the exception of A. capensis (Gamka) and A. pubigera which were the two most active species in the assay (IC50 values of 24.08 ± 4.42 μg/ml and 35.61 ± 0.86 μg/ml). The results obtained from the ABTS assay differed from that of the DPPH assay. All extracts showed greater activity in the ABTS assay with A. namaquensis and A. capensis (Besemfontein) being the most active species (IC50 values of 15.66 ± 4.57 μg/ml and 19.84 ± 0.09 μg/ml). Agathosma lanata (IC50 value of 26.17 ± 9.58 μg/ml) and A. ovata (round-leaf) (IC50 value of 25.20 ± 6.30 μg/ml) proved to be the most toxic in the MTT assay. Agathosma arida, A. collina, A. hirsuta, A. pubigera, A. roodebergensis, A. stipitata and A. zwartbergense also displayed some degree of toxicity.



Agathosma betulina | Rutaceae | Buchu | leaf | botanical   - Driefontein, Clanwilliam, South Western Cape, South Africa [2009 © alvaroviljoen.com]