Lipophilized derivatives of epigallocatechin gallate (EGCG): preparations and bioactivities

摘要

Green tea polyphenols (GTP) are a major source of dietary phenolics that render a myriadudof health benefits. Among GTP, epigallocatechin gallate (EGCG) is dominant and has been considered as being effective in both food and biological systems. However, its application and benefits may be compromised due to limited absorption and bioavailability. In order to expand the application of EGCG to more diverse systems, it may be lipophilized through structural modification.udIn this work, lipophilized derivatives of EGCG were prepared by acylation with different chain lengths fatty acyl chlorides such as acetyl chloride, C2:0; propionyl chloride, C3:0; hexanoyl chloride, C6:0; octanoyl chloride, C8:0; dodecanoyl chloride, C12:0; octadecanoyl chloride, C18:0; and docosahexaenoyl chloride, C22:6. The resultant products, mainly tetra-esters, were purified and their bioactivities evaluated, including antioxidant activities in different model systems and anti-glycation activities. The lipophilicity of the esters increased with increasing chain length of the acyl group and also led to the enhancement of their antioxidant properties that were evaluated using assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, oxygen radical absorbance capacity (ORAC) and reducing power of the molecules involved. These findings strongly suggest that the EGCG ester derivatives have great potential as lipophilic alternatives to the water-soluble EGCG.ud