Comparative Analysis of Antibacterial Activity and Membrane Permeability to Pathogenic Bacteria of Polyphenols Extracts from 3 Kinds of Tea

Objective:This paper mainly studied the antibacterial activity and its effect on cell membrane permeability of polyphenols from 3 kinds of tea. Methods:The west lake longjing, tieguanyin and puer tea were selected for tea polyphenols extraction. Inhibition diameter was determined by filter method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by double broth dilution. Cell membrane integrity and effect on DNA damage by tea polyphenols were evaluated by DNA permeability and DNA damage tests. Results:In the same conditions, polyphenols contents was (48.12±3.22) mg/g in green tea, (37.36±2.64) mg/g in wulong tea and (31.61±1.92) mg/g in black tea. Green tea had good antibacterial activity, and its inhibition diameter of Staphylococcus aureus was (1.80±0.06) cm, MIC value was 0.125 mg/mL, MBC value was 0.25 mg/mL. With the increasing of tea polyphenols concentration, bacteria material permeability increased gradually under 260 nm and the damage degree of genome DNA increased gradually. Conclusion:Green tea had better antibacterial ability in the three kinds of tea, and enhanced the bacterial cell membrane permeability, which would cause certain damage to DNA.