DOI: 10.12187/2025.06.005
Comparative study on antioxidant activity of EGCG and theaflavin based on density functional theory
XU Yucong
LI Wenzheng
FAN Maomei
BU Ying
ZHU Wenhui
LI Jianrong
LI Xuepeng
Abstract：[Objective]To investigate the structure-activity relationship between the antioxidant activities of EGCG/theaflavin and their molecular structures.[Methods]The molecular structures and corresponding free radicals of the main functional components—epigallocatechin gallate(EGCG)and theaflavin—in green/black tea were theoretically calculated using the density functional theory(DFT)method.The differences in antioxidant activity and solvation effects between EGCG and theaflavin were analyzed based on multiple antioxidant indices.[Results]Theaflavin exhibited higher antioxidant activity than EGCG,with a frontier molecular orbital energy gap ΔE(LUMO-HOMO)of 5.67 eV,a bond dissociation energy(BDE)of the C7′—OH phenolic hydroxyl of 321.9 kJ/mol,an ionization potential(IP)of 461.4 kJ/mol,and a spin population of the Cb—OH oxygen atom of 0.218.In non-polar solvents,sequential proton-loss electron transfer(SPLET)is preferred as the dominant reaction mechanism,while in polar solvents,single electron transfer followed by proton transfer(SET-PT)is preferred.The C5′—OH of the B ring may be the active site of EGCG,while the C7′—OH of the A′ ring may be that of theaflavin.[Conclusion]Theaflavin exhibits stronger antioxidant activity than EGCG,with the position of phenolic hydroxyl groups significantly influencing its activity.The DFT method offers a novel perspective for investigating the antioxidant activity of functional components in tea.
Keywords：epigallocatechin gallatetheaflavindensity functional theoryantioxidant activityfree radical
Publication Date：2025-12-15
Online Publishing Date：2025-12-22(First online date of this platform, not the publication date of the document)
Pages：11( 43-53 )