GLUCOSYLATION OF CAFFEIC ACID WITH BACILLUS-SUBTILIS X-23 ALPHA-AMYLASE AND A DESCRIPTION OF THE GLUCOSIDES

Caffeic acid was glucosylated with hydroquinone glucosylating enzyme ( HGE) from Bacillus subtilis X-23 in order to improve its characteristi cs. Caffeic acid glucosides were found to be produced effectively from maltopentaose and caffeic acid in 30% ethanol solution. The glucoside s were isolated from the reaction mixture by successive chromatography on DIAION HP-20, Sephadex G-10, and octadecyl sililated silica gel, f ollowing which two kinds of glucosides were obtained. The structures o f these glucosides were confirmed to be caffeic acid 3-O-alpha-glucopy ranoside and caffeic acid 4-O-alpha-glucopyranoside by H-1-NMR and C-1 3-NMR. The solubility of caffeic acid in water was increased by glucos ylation without the loss of any biological activity, such as its antio xidative and antimutagenic properties.