Inhibition of some hepatic lysosomal glycosidases by ethanolamines and phenyl 6-deoxy-6-(morpholin-4-yl)-β-d-glucopyranoside

The hepatic lysosomal glycosidases α-glucosidase and β-glucuronidase were inhibited in vitro and in vivo by mono- and diethanolamines. The in vivo inhibition is dose dependent and occurs at a value less than LD50. Phenyl 6-deoxy-6-(morpholin-4-yl)-β-d-glucopyranoside inhibited α-glucosidase both in vitro and in vivo. The treatment of the enzymes in vitro by ethanolamine exhibited a reversible inhibition of the mixed and competitive types for α-glucosidase and β-glucuronidase, respectively. Diethanolamine showed a reversible inhibition of the competitive type for both enzymes. It is a potent inhibitor for β-glucuronidase, in vitro, whose inhibition constant (Ki) is 5×10−5 M. Phenyl 6-deoxy-6-(morpholin-4-yl)-β-d-glucopyranoside is a potent inhibitor only for hepatic α-glucosidase with a Ki value of 1.6×10−5 M. The pattern of the pH dependence of enzymic activity was not affected by ethanolamine inhibition. The magnitude of the inhibition of enzymes is dependent on the structure of the inhibitor.