Synthesis and Characterization of Epigallocatechin Gallate Fructosides by using Levansucrase

Abstract

Levansucrase is one of fructosyltransferases and synthesizes levan, composed of β-(2-6)-linked fructose residues, or inulin, composed of β-(2-1)-liked fructose residues. Levansucrase also catalyzes transfructosylation from sucrose to a variety of acceptors. In this study, I expressed of levansucrase from Leuconostoc mesenteroides 512 in E. coli. The optimum condition for levansucrase expression is 1 mM lactose, 25 µM ampicillin at 33°C. The levansucrase activity was 2.84 U/mg. The production of levansucrase was used to catalyze transfructosylation using sucrose as substrate and pigallocatechin gallate (EGCG), one of the most abundant catechin in green tea, as acceptors. The five novel epigallocatechin gallate fructosis were detected. When compare to EGCG, water solubility of 5'-EGCG-β-D-fructofuranosyl-β-2-6-fructofuranoside was increased 350 mM, which is 64-fold water solubility of EGCG. Also antioxidant activities of EGCG-F2 (SC50, 9.7 μM) are similar to EGCG (SC50, 7.6 μM), and EGCG-F1 (IC50, 173.6 μM) showed higher inhibitory activity against HMA than EGCG-F2 (IC50, 253 μM).