Characterization of Novel Glycosides using the Glucansucrase

Abstract Six epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with 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 7,4"-O-α-D-glucopyranoside (EGCG-G2), epigallocatechin gallate 7,4′-O-α-D-glucopyranoside (EGCG-G3), epigallocatechin gallate 4"-O-α-D-glucopyranoside (EGCG-G4), epigallocatechin gallate 4′-O-α-D-glucopyranoside (EGCG-G5), and epigallocatechin gallate 4′,4" -O-α-D-glucopyranoside (EGCG-G6). Three of these compounds (EGCG-G1, EGCG-G2 and EGCG-G4) were novel compounds. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG ≥ EGCG-G1 p EGCG-G4 p EGCG-G5 p EGCG-G2 p EGCG-G3p EGCG-G6), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G5, EGCG-G4, EGCG-G3, EGCG-G6, and EGCG-G2 were 49, 55, 71, 114, 125, and 130 times as water soluble, respectively, as was EGCG. Two arbutin glucosides were also synthesized via the acceptor reaction. The purified glucosides were elucidated as 4-hydroxyphenyl α-isomaltoside (arbutin-G1), 4-hydroxyphenyl α-isomaltotrioside (arbutin-G2). Arbutin glucoside (4-hydroxyphenyl β-isomaltoside) exhibited slower effects on DPPH radical scavenging and similar effects on tyrosinase inhibition, and increased inhibitory effect on MMP-1 production induced by UVB than arbutin.