Separation and Antioxidant Activities of New Acetylated EGCG compounds

Acetylation could improve the bioavailability of (-)-Epigallocatechin-3-Gallate (EGCG), but the relationship of 11 substitution degree and antioxidant capacity of acetylated EGCG was unclear. The acetylated EGCG products were separated 12 by preparation high performance liquid chromatography (HPLC). Two mono substituted acetylated EGCG, three substituted 13 acetylated EGCG (T-AcE), eight substituted acetylated EGCG (E-AcE) and (-)-Epigallocatechin gallate (EGCG) were isolated. 14 The 7-acetyl-EGCG (S7-ACEGCG) and 7-acetyl-EGCG (T-AcE) were identified for the first time. The antioxidant capacity, 15 superoxide anion radical scavenging capacities, and hydroxyl radical scavenging capacities of EGCG decreased significantly 16 after acetylation modification. The more EGCG acetylation modification sites, the lower the total antioxidant capacity, 17 superoxide anion radical scavenging capacities, and hydroxyl radical scavenging capacities. The antioxidant capacity, 18 superoxide anion radical scavenging capacities, and hydroxyl radical scavenging capacities of 5-acetyl-EGCG (S5-ACE) were 19 higher than 7-acetyl-EGCG (S7-AcE). Combining all the results in this and previous studies, acetylation modification is not 20 conducive to the performance of EGCG antioxidant capacity.