Lipophilised epigallocatechin gallate (EGCG) derivatives and their antioxidant potential in food and biological systems

Abstract

Epigallocatechin gallate (EGCG) was structurally modified for enhanced lipophilicity and hence expanded applications, as well as improved cellular absorption in vivo. Ester derivatives of EGCG with stearic acid, eicosapentaenoic acid and docosahexaenoic acid were prepared. All EGCG derivatives inhibited oxidation of bulk oil, and their potency was superior or similar to that of the parent EGCG molecule. The derivatives were more efficient than EGCG in inhibiting oxidation in a β-carotene/linoleic acid emulsion and pork model systems, and their efficiency correlated well with their lipophilicity. In biological systems, the ester derivatives showed higher cell membrane affinity and therefore better cellular absorption than EGCG. The derivatives were more effective than EGCG against Cu2+-induced LDL-cholesterol oxidation and also effectively inhibited hydroxyl and peroxyl radical-induced DNA scission and UV-induced liposome oxidation. These results suggest that EGCG esters may be used in food as lipophilic alternatives to EGCG, without compromising functional and physiological properties. Moreover, EGCG-polyunsaturated fatty acid esters may render additional advantages to human health. © 2011 Elsevier Ltd. All rights reserved.