Synthesis and Biological Testing of Novel Glucosylated Epigallocatechin Gallate (EGCG) Derivatives.

Xin Zhang,Ye-Wei Huang,Xiao-Yun Wu,Jiang-Miao Hu,Xuan-Jun Wang,Jun Sheng,Jing Wang,Cheng-Ting Zi

doi:10.3390/molecules21050620

Abstract

Epigallocatechin gallate (EGCG) is the most abundant component of green tea catechins and has strong physiological activities. In this study, two novel EGCG glycosides (EGCG-G1 and EGCG-G2) were chemoselectively synthesized by a chemical modification strategy. Each of these EGCG glycosides underwent structure identification, and the structures were assigned as follows: epigallocatechin gallate-4′′-O-β-d-glucopyranoside (EGCG-G1, 2) and epigallocatechin gallate-4′,4′′-O-β-d-gluco-pyranoside (EGCG-G2, 3). The EGCG glycosides were evaluated for their anticancer activity in vitro against two human breast cell lines (MCF-7 and MDA-MB-231) using MTT assays. The inhibition rate of EGCG glycosides (EGCG-G1 and EGCG-G2) is not obvious. The EGCG glycosides are more stable than EGCG in aqueous solutions, but exhibited decreasing antioxidant activity in the DPPH radical-scavenging assay (EGCG > EGCG-G2 > EGCG-G1). Additionally, the EGCG glycosides exhibited increased water solubility: EGCG-G2 and EGCG-G1 were 15 and 31 times as soluble EGCG, respectively. The EGCG glycosides appear to be useful, and further studies regarding their biological activity are in progress.

Highlights

Green tea has been consumed by human beings for thousands of years and is an important source of tea catechins
We report the synthesis of epigallocatechin gallate (EGCG) glycosides by a chemical strategy, in which the 4′- and 4′′-hydroxyl groups of EGCG (EGCG-G2, 3, Figure 1)
Data (Figure 2), the chemical shift of C-411 was observed at 137.1 ppm, and coupling appeared to have occurred between C-411 and H-1111 (4.87 ppm, d, J = 9.0 Hz) of the glucosyl residue, which indicated that the glucosyl residue had been attached to C-411 of the EGCG, whereas C2 11 -H, C6 11 -H

Summary

Introduction

Green tea has been consumed by human beings for thousands of years and is an important source of tea catechins. EGCG has been studied previously for its effects in inducing breast cancer apoptosis and cell-cycle arrest [9,10]. Molecules 2016, 21, 620 breast cancer cell proliferation by inhibiting the α9-nAChR signaling pathway [11] and could block. Wnt signaling by inducing the HBP1 transcriptional repressor to inhibit aspects of invasive breast cancer [12]. These mechanisms reveal repressor that EGCG have significant chemopreventive by inducing the HBP1 transcriptional tomay inhibit aspects of invasive breast cancerapplications [12].

Methods

Results

Conclusion