Glucosidases catalyze the cleavage of individual glucosyl residues from various glycoconjugates, including complex carbohydrates and glycoproteins. Castanospermine is an inhibitor of both α- and β-glucosidases, inhibiting lysosomal and neutral α-glucosidases with Ki values of 0.1 and 10 μM, respectively, and lysosomal and cytosolic β-glucosidases with Ki values of 7 and 40 μM, respectively. It is effective both in vitro and in vivo. Through its effects on glucosidases, castanospermine blocks N-linked glycosylation during post-translational modification of proteins, affecting protein trafficking and cell functions that are dependent on glycosylation, including angiogenesis. Castanospermine also interferes with viral replication and infection that is dependent on glucosidase activity.
