The synthesis of two polyhydroxylated pyrrolidines as 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) analogues bearing a hydrazide moiety is described. The DAB analogues act as selective and potent inhibitors of α-mannosidase in the submicromolar concentration ranges (Ki values ranging from 0.23 to 1.4 μM)