Lipophilization of EGCG and effects on antioxidant activities.

A green, fast, and efficient method for synthesizing lipophilic epigallocatechin gallate (EGCG) derivatives was set up for the first time. EGCG was lipophilized by esterification in order to promote its application in lipid products and to possibly enhance its bioactivity. A high conversion of EGCG was achieved. Three monoesters of the EGCG derivatives were confirmed by high performance liquid chromatography-mass spectrometry, and the predominant one was identified as 4'-O-palmitoyl EGCG by nuclear magnetic resonance. The EGCG derivatives exhibited good radical scavenging capacities. In lard the solubility of EGCG derivatives was enhanced 470 times compared to EGCG, and they exhibited excellent antioxidative activity in the oil. These results indicate that the palmitoylated EGCG derivatives may be used as potent antioxidants in lipophilic medium, such as edible oils and fatty foods. In addition, this method can be applied to commercial application, producing antioxidants to substitute for synthetic ones like tert-butylhydroquinone.