Study on the Mechanism of Epigallocatechin Gallate (EGCG) to the Cell Membrane of Escherichia coli

Tea polyphenols have disinfection ability, but the mechanism of tea polyphenols on bacteria is still unclear. The changes of E. coli cell membrane were monitored by using EGCG, a catechin monomer with high content in tea polyphenols, as the main disinfectant. Aiming at the main factors affecting the oxidative polymerization of EGCG, three factors and three levels orthogonal test were designed. From the quantitative point of view, the damage law of EGCG on E. coli cell membrane under different conditions was obtained, and then the destruction mechanism model of EGCG on E. coli cell membrane was established. The results showed that EGCG could increase the permeability of E. coli outer membrane and inner membrane, accordingly, depolarize the cell membrane. Experimental optimum conditions is 60 mg/L EGCG, pH = 8.0 at temperature of 25 degrees C, which was beneficial to the oxidation polymerization of tea polyphenols.