New substituted pyrrolidine-3,4-diol derivatives were prepared from d-(-)- and l-(+)-phenyl
glycinol. The influence of the configuration and the substitution of the lateral side chain of these derivatives on the inhibition of 25 commercial
glycosidases were determined. (2R,3R,4S)-2-({[(1R)-2-Hydroxy-1-phenylethyl]amino}methyl)
pyrrolidine-3,4-diol ((+)-7a) was a potent and selective inhibitor of jack bean
alpha-mannosidase (K(i) = 135 nM). However, when evaluated on human
tumor cells, 7a, and the reference compound
swainsonine, did not efficiently inhibit the growth of
glioblastoma cells. Further derivatization of the
hydroxyl group with lipophilic groups to increase bioavailability improved their growth inhibitory properties for human
glioblastoma and
melanoma cells. In particular, the 4-bromobenzoyl derivative 26 demonstrated high efficacy for human
tumor cells whereas primary human fibroblasts were less sensitive to 26. Therefore, functionalized
pyrrolidines have the potential to inhibit the growth of
tumor cells and display selectivity for
tumor cells when compared to normal cells.