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Grant Abstract

Grant Number: 1R21AT002076-01
PI Name: Amy Howell
Project Title: Identification of Bioactive Cranberry Metabolites

Abstract: DESCRIPTION (provided by applicant): Cranberries have been clinically studied to assess their potential role in prevention of urinary tract infections. The results have been generally favorable, but many of the studies have been criticized for design flaws. One vital component at issue is participant adherence to study dosage, which has been particularly difficult to assess due to the lack of a reliable compliance marker. A quantifiable urinary metabolite(s) would be an ideal compliance marker for clinical trials, as the level could be associated with a biologically effective dosage of cranberry. Proanthocyanidins have been identified as the potential active compounds in cranberry, preventing the in vitro adhesion of P-fimbriated uropathogenic bacteria to uroepithelial cells, and producing an anti-adhesion effect in mouse urine following ingestion. However, the proanthocyanidin urinary metabolites have never been elucidated. The objectives of this proposal are to utilize bioassay-directed fractionation to isolate and identify the molecular structures of the active urinary metabolites and to determine the scope of the bacterial anti-adhesive properties of these metabolites. The long-term goal is to identify and quantify the levels of the active urinary metabolites so they can be utilized as markers for measuring compliance in clinical research. Urine will be collected over time from swine that have been fed defined quantities of standardized cranberry powder. Bioassay-directed fractionation of urine will be performed to identify active compounds. Assays will measure the ability of the fractions and subsequent pure compounds to prevent the adhesion of P-fimbriated E. coli. The structures of the active compounds will be identified by a range of spectroscopic techniques, including HPLC/API MS, LC/MS/MS, NMR and MALDI/TOF. The scope of activity of the metabolites will be measured by testing their anti-adhesion ability against a range of uropathogenic E. coli bacteria with known virulence factors. This will establish their utility for use as a broad-spectrum marker for measuring compliance to cranberry protocols.

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