Novel alpha-mannosidase inhibitors of the type (2R,3R,4S)-2-({[(1R)-2- hydroxy-1-arylethyl]amine}methyl) pyrrolidine-3,4-diol have been prepared and assayed for their anticancer activities. Compound 30 with the aryl group = 4-trifluoromethylbiphenyl inhibits the proliferation of primary cells and cell lines of different origins, irrespective of Bcl-2 expression levels, inducing a G2/Mcell cycle arrest and by modification of genes involved in cell cycle progression and survival. (C) 2010 Elsevier Ltd. All rights reserved.