Enzymatic syntheses of dopamine glycosides

Glucoamylase from Rhizopus mold and β-glucosidase catalysed synthesis of dopamine-d-glucoside was optimized in terms of pH, buffer, enzyme, dopamine concentrations and incubation period in organic media. Under the optimum conditions, β-glucosidase showed regioselectivity by giving rise to 3-hydroxy-4-O-(β-d-glucopyranosyl)phenylethylamine 5b. Presence of hydroxyl group at 3rd and 4th position of phenyl ring showed only monoglycosylation/arylation products with d-glucose 2, d-galactose 3 and d-mannose 4 for both the enzymes. Synthesized glycosides also exhibited ACE inhibition and antioxidant activities.