Tea polyphenols inhibit Pseudomonas aeruginosa through damage to the cell membrane

This paper aims to delineate the inhibition mechanism of tea polyphenols (TP) toward Pseudomonas aeruginosa by cell membrane damage. Morphological changes in bacteria treated with TP were investigated by transmission electron microscopy, with results indicating that the primary inhibitory action of TP is to damage bacterial cell membranes. TP also increased the permeability of the outer and inner membranes of P. aeruginosa and disrupted the cell membrane with the release of small cellular molecules. A proteomics approach based on two-dimensional gel electrophoresis and MALDI-TOF/TOF MS analysis was used to study the differences in the membrane proteins of TP-treated P. aeruginosa and those of control samples. Twenty-seven differentially expressed proteins were observed in the treated and the control groups. Most of the proteins identified by MALDI-TOF/TOF MS were enzymes (dihdrollpoamide dehydrogenase 50s ribosomal protein, and so on), which may have induced the metabolic disorder of the bacteria and resulted in their death. (C) 2010 Elsevier B.V. All rights reserved.