Anti-Adhesion Capacities of Cranberry Polyphenols and Metabolites Against Type-P and Type-1 Fimbriated Uropathogenic E. Coli Tested Using a Fluorometric Method

Adhesion of type-P and type-1 fimbriated uropathogenic E. coli (UPEC) to uroepithelial cells initiates urinary tract infections (UTIs). This research aimed to evaluate the capacities of cranberry polyphenols and their microbial metabolites to inhibit such adhesion in vitro using a modified fluorometric method. Data showed that the inhibition capacity of myricetin increased with concentration and plateaued at 70%. It had IC 50 values of 13.2 μM against type-P E. coli and 5.50 μM against type-1 E. coli . Quercetin showed similar anti-adhesion capacities to myricetin. Procyanidin A2 and B2 had weaker anti-adhesion activities than myricetin and quercetin with maximal inhibition capacity of 20-30% against UPEC. Hippuric acid, a major metabolite of cranberry polyphenols in human urine, showed a maximal inhibition of 20% at 558 μM against type-1 E. coli adhesion, whereas no anti-adhesion activity against type-P E. coli was detected. Cranberry fruit fractions enriched with procyanidin polymers showed the highest anti-adhesion activity compared to fractions enriched with anthocyanins, flavonols, or anthocyanins. Overall, anti-adhesion activities of cranberry polyphenols and metabolites depend on the structures of these compounds and the types of fimbriae on E. coli