Epigallocatechin gallate (EGCG) esters with different chain lengths fatty acids and their antioxidant activity in food and biological systems

Ester derivatives of epigallocatechin gallate (EGCG) were prepared by acylation with different chain lengths acyl chlorides, namely acetyl chloride, C2:0; propionyl chloride, C3:0; caproyl chloride, C6:0; capryloyl chloride, C8:0; lauroyl chloride, C12:0; stearoyl chloride, C18:0; and docosahexaenoyl chloride, C22:6. The resultant products, mainly tetra-esters, were purified and their lipophilicity, radical scavenging ability and antioxidant activities in food (bulk oil, β-carotene/linoleate emulsion and ground meat) and biological systems (LDL cholesterol and DNA) evaluated. The lipophilicity of the esters increased with increasing chain length of the acyl group and also led to the enhancement of their antioxidant properties. These findings strongly suggest that the EGCG ester derivatives have great potential as lipophilic alternatives to the water-soluble EGCG.