Enzymatic preparation of N-substituted 4-O-α-D-glucopyranosylmoranoline derivatives

A transglycosylation reaction with A-substituted moranolines was carried out with soluble starch as the glucose donor and cyclodextrin glycosyltransferase [EC 2.4.1.19] from Bacillus stear other-mophilus, the degree of A-substituted moranolines that were converted to transglycosylation products being within the range of 60~81%. The resultant transglycosylation products were hydrolyzed by glucoamylase [EC 3.2.1.3] from Rhizopus niveus, and the degree of A-substituted moranolines that were converted to A-substituted 4–0-α-d-glucopyranosylmoranolines was within the range of 53 ~ 72 %.The inhibitory activities of A-substituted 4–0-α-d-glucopyranosyImoranolines against cyclodextrin glycosyltransferase were greater than those of the corresponding ^-substituted moranolines, and N-substituted 4-O-α-d-glucopyranosylmoranolines lost the inhibitory activities against glucoamylase. Among these A^-substituted 4–0-α-d-glucopyranosylmoranolines, the A-methyl derivative was a very potent inhibitor.