Synthesis, Structure Analyses, and Characterization of Novel Epigallocatechin Gallate (EGCG) Glycosides Using the Glucansucrase from Leuconostoc mesenteroides B-1299CB

In this study, three epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with epigallocatechin gallate (EGCG) and sucrose. Each of these glycosides was then purified, and the structures were assigned as follows: epigallocatechin gallate 7-O-α-d-glucopyranoside (EGCG-G1); epigallocatechin gallate 4‘-O-α-d-glucopyranoside (EGCG-G1‘); and epigallocatechin gallate 7,4‘-O-α-d-glucopyranoside (EGCG-G2). One of these compounds (EGCG-G1) was a novel compound. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG ≥ EGCG-G1 > EGCG-G1‘ > EGCG-G2), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G1‘, and EGCG-G2 were 49, 55, and 114 times as water soluble, respectively, as EGCG. Keywords: Leuconostoc mesenteroides glucansucrase; EGCG; glycoside; acceptor reaction