Efficient enzymatic modification of epigallocatechin gallate in ionic liquids

• Main Authors: Song Zhu, Na Meng, Yue Li, Shang-Wei Chen
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2021-04-01
• Series: Green Chemistry Letters and Reviews
• Subjects: egcg derivatives; ionic liquids; enzymatic; immobilized lipase
• Online Access: http://dx.doi.org/10.1080/17518253.2021.1926549

Epigallocatechin gallate (EGCG), the main polyphenolic substance in tea, exhibits well-known biological benefits. In order to improve fat solubility and bioavailability, a novel path for the lipase enzymatic transesterification synthesis of acylated EGCG derivatives in an ionic liquid solvent was established. The optimal reaction parameters were determined and a maximum conversion of the transesterification reaction was achieved at 98.65%. [Bmim][BF4] was the best reaction medium and the immobilized lipase Novozym 435 was the best catalyst. The enzyme was added to a final concentration of 2% (w/w, EGCG), and the reaction was performed at an optimum temperature of 70°C stirring for 10 h at 250 rpm. The most suitable acyl donor, vinyl acetate, and EGCG were mixed at a molar ratio of 90:1 for the reaction. The structure of the purified acetylated EGCG was determined to be 5″-O-acetyl-EGCG and 3″, 5″-2-O-acetyl-EGCG by mass spectrometry, NMR, and infrared analyses.