SEQUENTIAL GLUCOSYLATION DETERMINED BY NMR IN THE BIOSYNTHESIS OF MULBERROSIDE-D, A CIS-OXYRESVERATROL DIGLUCOSIDE, IN MORUS-ALBA L CELL-CULTURES

Three new diglucosides, mulberrosides D, E, and F, were isolated from Morus albu cell cultures and their structures were established by spec troscopy. In the biosynthesis of mulberroside D, a cinnamoylpolyketide -derived cis-oxyresveratrol diglucoside in the cell cultures, the diff erent ratio of C-13-enrichment between two glucose moieties of mulberr oside D, revealed by administering [U-C-13(6)]-D-glucose and [1,3-C-13 (2)]glycerol to the cell cultures, suggested that two glucosylation st eps in the biosynthesis of the glucoside occur with different time cou rses.