Pomegranate materials inhibit flagellin gene expression and flagellar-propelled motility of uropathogenic Escherichia coli strain CFT073

This report describes the inhibitory effect of pomegranate rind extract (PGRE) on the motility of uropathogenic Escherichia coli (UPEC), a common agent of uncomplicated urinary tract infections (UTIs). To this end, a fliC-lux reporter, as well as Western blot analysis and scanning electron microscopy, was used to demonstrate that when UPEC strain CFT073 is exposed to PGRE, expression of the flagellin gene, fliC, and flagellin production decrease. In agreement with these results, the swimming and swarming motilities of UPEC were observed to be hindered in the presence of PGRE. To evaluate the effect of other pomegranate materials (PMs), the hydrolysable tannins in pomegranate (PG; punicalagin) and pomegranate fruit powder (PGP) were also investigated. Of the materials tested, PGRE had the strongest inhibitory effect on fliC expression and motility. Moreover, a fractionation of PGRE showed fractions with a molecular weight between 1000 and 3000 similar to kDa to be the strongest inhibitors of fliC expression. Because flagellum-mediated motility has been suggested to enable UPEC to disseminate to the upper urinary tract; we propose that PGRE might be therapeutically beneficial in the treatment and prevention of UTIs.