The non-geranylated intermediates (2a, 2d–f) exhibited weak inhibitory activities (>100 μM), while
the preservation of the geranyl moiety as in compounds (3a, 3c, 3e–g) improved the enzyme inhibitory
activities. In terms of SARs, compound 3a is slightly less potent when compared to tHGA. However,
the removal of a branched methyl group as in compound 3c resulted in a two-fold increment in activity
in comparison with tHGA. Elongation of the aliphatic chain length of the acyl group to 5Cs as in
compound 3e yielded the most potent inhibitor in this series (IC50 = 10.31 μM ± 1.5). The dose
response curves of compound 3e and tHGA are showed in Figure 3.