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

Since the 7α-isomers of compounds I and II (36 and 33, respectively) exhibited the
above mentioned activity, it was decided to determine the antibacterial activity and
anticancer activity of these two compounds. The bacterial strains tested were that of E.
faecalis and P. aeruginosa with the hope of these two compounds exhibiting greater
activity than that reported in literature where 33 and 36 (having MIC values of
62.50µg/mL and 31.25µg/mL and 15.63µg/mL and 31.25µg/mL against two VRE strains,
respectively) displayed stronger activity against VRE than vancomycin (having a
minimum MIC value of 125µg/mL) and where 36 displayed more potent activity against
MRSA (with MIC values averaging 7.8µg/mL) than oxacillin (having a MIC value of
15.63µg/mL) (Gaspar-Marques et al., 2006). The 7-acetoxy function also proved
superior in activity to the 7-hydroxy function when tested for anticancer activity against
MCF-7, NCI-H460, SF-268, TK-10 and UACC-62 cell lines (Gaspar-Marques et al.,
2002). The purpose of the anticancer testing performed in this study was to see how the
isomers of 36 and 33, I and II respectively, faired in the anticancer assays.
Even though, compound III has been isolated by Ansell (1989) there hasn’t been any
report of this compound showing biological activity. The only report of an ent-pimarene
displaying antibacterial activity was by Porto et al. (2009) where ent-8(14),15-
pimaradien-3β-ol was found to be active against E. faecalis having an an MIC value of
20µg/mL. It is still unknown as to whether ent-pimarene compounds possess anticancer
activity as they have not been tested against any cell lines to date.
There were three reports of anticancer testing of compound IV, however none of these
studies tested for activity against the TK-10 (renal) and UACC-62 (melanoma) cell lines.
Cheng et al. (2010) tested compound IV for activity against four human cancer cell lines
(MCF-7, tested in this work, NCI-H460, HT-29 and CEM) (Cheng et al., 2010). The
results indicated that this compound was inactive as an anticancer agent based on cancer
cell proliferation (Cheng et al., 2010). Studies by Ogura et al. (1977) and Mujovo (2010)
proved that compound IV does possess anticancer activity by testing positive for activity
against P-388 lymphocytic leukaemia cell lines (Ogura et al., 1977) and exhibiting strong
142