Antimicrobial activity of 10 different plant polyphenols against bacteria causing food-borne disease

The antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (MICs) against several food-borne pathogenic bacteria, Staphylococceus aureus (20 strains), some serotypes of the genus Salmonella (26 strains), Escherichia coli (23 strains), and some species of the genus Vibrio (27 strains). The polyphenols examined were epigallocatechin (1). epigallocatechin-3-O-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelphinidin (6). geraniin (7)2 procyanidins (8) a theaflaAn mixture of black tea (9), and green tea polyphenols treated with loquat polyphenol oxidase (10). The average MICS of all polyphenols against S. auretts and the genus Vibrio (192 +/- 91 and 162 +/- 165mug/ml. respectively) were much lower than the values against the genus Sahnonella and E. coli (795 +/- 590 and 1519 +/- 949 mug/ml. respectively) (p<0.01). The coefficient of variation of the MICs of all polyphenols against S. aureus was the least and that against the genus Vibrio was the greatest. The mean MICs of each plant polyphenol against S. aureas (98389 Ag/ml) and the genus Vibrio (68-488 mug/ml) were similar. The relatively lower mean MIC values of 1. 2. 5. and 6 suggest the importance of 3,4,5-trihNdroxyphenyl groups in antibacterial activitv.