Transglycosylation and biochemical characterization of epigallocatechin gallate glucosides using dextransucrase

Abstract

Green tea (Camellia sinensis) has attracted significant attention, both in the scientific and in consumer communities, because of its health benefits for a variety of disorders, ranging from cancer to weight loss. Epigallocatechin gallate (EGCG) is the most abundant catechin and the main polyphenolic components of green tea. Although EGCG possess various biological activities but EGCG has limited for application in functional food, cosmetic because of its low solubility. In this study epigallocatechin gallate glucosides (EGCG-Gs) were synthesized by acceptor reaction using dextransucrase from Leuconostoc mesenteroides B-1299CB expressed in E. coli and analyzed their solubility. The solubility was measured by HPLC using C18 column. Novel compounds have shown 42 to 347-folds higher solubility than that of EGCG, especially the solubility of compound 6 (EGCG-5-O-a-D-glucopyranoside) was 1878.47 mM. With this, glucosylated EGCG could be utilized highly in various fields. Additionally While EGCG being studied as cosmetic materials for brightening effect, in this study EGCG and its glucosides activated human tyrosinase expressed in E.coli and produce melanin unlike mushroom tyrosinase. In biofunctionally, EGCG-Gs have less cell cytotoxicity on epidermal cells than it of EGCG, therefore EGCG-Gs could be treated up to 200 μM. In addition, EGCG-Gs have higher inhibition ability to produce nitric oxide than EGCG up to 68% in Raw 264.7 cells related with skin aging. Melanin synthesis in B16F10 cells is also inhibited up to 40% (compound 4, EGCG-7,5',4''-O-α-D-glucopyranoside ).