Mmushi T MSc (Microbiology).pdf
Mmushi T MSc (Microbiology).pdf
Mmushi T MSc (Microbiology).pdf
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this plant. However, as can be seen the MIC value of the acetone extracts of A.<br />
dimidiata was 0.63 mg/ml and this MIC value increased to more than 2.5 mg/ml with the<br />
purified compound. It is uncommon to find that the initial crude extract has a lower MIC<br />
and as it is fractionated the MIC increases (Jean et al., 2001). Various researchers have<br />
cited the following reasons for this increase. Firstly, the crude extract may have several<br />
compounds which act simultaneously on the test organism. Alternatively, several<br />
compounds may act synergistically to inhibit growth. Therefore, as fractionation takes<br />
place some of constituent compounds may be lost. When one compares the MIC values<br />
for the two purified compounds against rifampicin they were found to be 10 fold weaker.<br />
The two compounds were isolated in relatively small amounts (25 mg and 39 mg,<br />
respectively). However the compounds were inactive at MIC value of 2.5 mg/ml against<br />
all the tested organisms, (results not shown). The data obtained from nuclear magnetic<br />
resonance (NMR) results suggested that the compounds isolated were long fatty acids<br />
chain (compound A) and a triterpene (compound B). We could not establish this<br />
conclusively as more plant materials were required to enable further testing and there<br />
was not sufficient time to redo the purification of these compounds. There is certainly a<br />
need to increase the amount of purified compounds to enable further mass<br />
spectroscopy analysis in order to identify the compounds conclusively. The cytotoxicity<br />
and mode of action of the bioactive compounds has to be ascertained.<br />
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