university of kwazulu-natal faculty of science and agriculture school ...

This indicated that the dihydroxy compound had better activity than its monoacetylated
counterpart. This is different from that in the literature where the dihydroxy isomer (33)
showed worse activity with MIC values of 62.50 and 31.25µg/mL than the isomer of the
acetylated compound (36) with MIC values of 15.63 and 31.25µg/mL against two strains
of vancomycin-resistant E. faecalis. Even though our compounds displayed weaker
activity than the antibiotic, gentamicin, they do exhibit stronger activity than that reported
for vancomycin in Gaspar-Marques et al. (2006).
4.2 Anti-cancer screening
An in-house test method which was developed by the CSIR was employed for the
evaluation of the anticancer activity of compounds I to IV. This test method was
implemented by the CSIR in 1999 and is known as the three cell prescreening method
(Fouche et al., 2006; 2008). Breast (MCF-7), renal (TK-10) and melanoma (UACC-62)
cell lines were three human cell lines chosen for anticancer testing due to their high
sensitivity to detect anticancer activity (Fouche et al., 2008). Compounds need to
demonstrate growth inhibitory activity in this pre-screen panel before proceeding to
advanced testing in the full 60-cell-line screen.
Melanoma refers to cancer of the skin and occurs when a UV photon strikes a
chromophore in a skin cell. A chromophore is the part of a molecule which gives it
colour. When the chomophore is struck by the UV photon, a singlet oxygen ( 1 O2) or
hydroxyl (•OH) free radical is produced, which then travels about the body until it finds a
home in a melanocyte, where DNA is mutated by means of oxidation. The damaged
melanocyte then becomes a malignant tumour, which is apparent by a change in skin
colour, usually to a darker shade. Genetic predisposition, excessive, unprotected
exposure to the sun as well as the use of tanning or sun beds are some of the factors
which lead to the formation of melanomas.
Breast cancer is a form of cancer which originates from breast tissue, commonly found in
the inner lining of milk ducts or lobules, the ducts responsible for the supply of milk.
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