PURPOSE: Vaccinium macrocarpon--the American cranberry--irreversibly inhibits the expression of P-fimbriae of E. coli. Further effects on the function and expression of P-fimbriae were studied by growing P-fimbriated E. coli in solid media laced with cranberry juice.

METHODS: Cranberry concentrate at pH 7.0 was added to CFA medium to a final concentration of 25%. E. coli strains JR1 and DS17 were plated on this medium with a plain CFA control and incubated at 37C. Cultures were tested for ability to agglutinate P-receptor specific beads. Bacteria were washed in PBS and agglutination retested. Cultures were also replated on plain CFA agar and rechecked for their ability to agglutinate. Transmission electron micrographs were performed on positive control and test bacteria.

RESULTS: For E. coli strain JR1, P-fimbrial agglutination was inhibited after the third plating. DS17 was fully inhibited after the second plating. Washing in PBS did not affect agglutination, but replating on CFA agar allowed agglutination to recur. Electron micrographic study of control populations confirmed fimbriae. Fully inhibited bacteria had a 100% reduction in expression of fimbriae. Additionally, inhibited bacteria showed cellular elongation.

CONCLUSIONS: Cranberry juice irreversibly inhibits P-fimbriae. Electron micrographic evidence suggests that cranberry juice acts on the cell wall preventing proper attachment of the fimbrial subunits or as a genetic control preventing the expression of normal fimbrial subunits or both.

Because previous studies have shown that a high molecular mass constituent of cranberry juice inhibited adhesion of Escherichia coli to epithelial cells and coaggregation of oral bacteria, we have examined its effect on the adhesion of Helicobacter pylori to immobilized human mucus and to erythrocytes. We employed three strains of H. pylori all of which bound to the mucus and agglutinated human erythrocytes via a sialic acid-specific adhesin. The results showed that a high molecular mass constituent derived from cranberry juice inhibits the sialic acid-specific adhesion of H. pylori to human gastric mucus and to human erythrocytes.

Phenolics from the American cranberry (Vaccinium macrocarpon) were fractionated into a series of proanthocyanidins and other flavonoid compounds by vacuum chromatography on a hydrophilic, porous polyvinylic gel permeation polymer. Antioxidant activity was not restricted to a particular class of components in the extract but was found in a wide range of the fractions. Significant chemopreventive activity, as indicated by an ornithine decarboxylase assay, was localized in one particular proanthocyanidin-rich fraction from the initial fractionation procedure. Further fractionation of the active anticarcinogenic fraction revealed the following components: seven flavonoids, mainly quercetin, myricetin, the corresponding 3-O-glycosides, (-)-epicatechin, (+)-catechin, and dimers of both gallocatechin and epigallocatechin types, and a series of oligomeric proanthocyanidins.

In the 20th century, the health benefit most often attributed to the cranberry is its role in maintaining urinary-tract health. A 1998 study by the International Food Information Council (personal communication) indicated that 47% of consumers surveyed were aware of a link between cranberry juice and urinary-tract health.

Phytochemicals from North American cranberry (Vaccinium macrocarpon) fruit may be expected to influence the development of colon cancer. Tissue-culture models were used to assess effects of cranberry components on cell proliferation, apoptosis, and the formation of tumor cell colonies. Several phytochemicals and fractions isolated from whole cranberry fruit were previously reported to inhibit growth and proliferation of breast, colon, prostate, and other tumor cell lines. In HT-29 and HCT116 colon tumor cell lines, cranberry proanthocyanidins (PACs) and ursolic acid inhibited the formation of tumor colonies over a two week period in a dose-dependent manner. Apoptosis is likely to play a role in limiting tumor cell proliferation. In HT-29 and HCT116 colon tumor cell lines treated with either ursolic acid or a cranberry proanthocyanidin fraction, the percentage of cells undergoing apoptosis increased in a dose-dependent manner. Thus, cranberry phytochemicals have the potential to limit carcinogenesis.

Twenty-one female and 19 male subjects who had normal physical and laboratory examinations were randomly assigned into four groups of 10 subjects each. Each group was then randomly assigned a number (150, 180, 210, 240) which determined the amount of cranberry juice, in milliliters, members of that group would ingest with each meal during the experimental phase of the study. The study took place over a 12-day period. A one-group before-and-after design was used, with each subject serving as his or her own control. Diet was controlled; menus on days 1 through 6 were repeated on days 7 through 12 with the addition of cranberry juice at each meal. Subjects used nitrazine pH tape to measure the pH of midstream urine at each voiding. There were significant (.01 level) differences in mean urinary pH between each control group and its corresponding experimental group. Anticipated problems with increased number of bowel movements, weight gain, increased voiding frequency, and subject pH measurement inaccuracy did not occur.

Most research suggests that ingestion of cranberry juice may be useful in preventing urinary tract infections. This pilot study examines the effect of drinking moderate amounts of commercially available cranberry juice cocktail on urinary pH in older, institutionalized adults. The results of the study have implications for home care nurses who have similar patients in their case loads.

The purpose of this study was to quantitate the effect of cranberry juice ingestion on urinary acidification and calcium excretion, in a diet-controlled situation.

The influence of diet on aryl acid metabolism was determined in normal and azotemic subjects. Aryl acid content of serum and urine was estimated by fluorometry in relation to hippuric acid as a standard (FI-Hipp). Secretory activity, a reflection of the biological potency of aromatic acids in serum and urine, was determined by bioassay. The urinary excretion of FI-Hipp and secretory activity of five normal persons on an ad lib diet was 0.78 and 2.25 mM/day, respectively; similar values were observed in two subjects with chronic renal insufficiency. Subjects were fed prunes and cranberries, since these foods contain abundant quantities of hippurate precursors. Prunes 1.5 g/kg body weight, caused the urinary excretion of both FI-Hipp and secretory activity to increase about tenfold in normal and azotemic subjects. Prune feeding caused the serum levels of FI-Hipp and secretory activity to increase about threefold. Cranberries increased the renal excretion of FI-Hipp and secretory activity as did the ingestion of a beverage containing benzoate as a preservative. On the basis of these studies it is clear that diet is an important determinant of the load of aryl acids for urinary excretion; in patients with renal insufficiency the ingestion of foods containing precursors may cause serum level of biologically active aryl acids to increase strikingly.

This study investigated that the antioxidative effect of freeze-dried cranberry powder against protein and lipid oxidation and ameliorative effect of serum lipid profile in rat fed atherogenic diet. Six weeks old male Sprague-Dawley rats were divided into the following four groups: normal diet group with 5% corn oil (control), atherogenic diet group with 5% corn oil, 10% lard, 1% cholesterol, and 0.5% sodium cholate (HFC), atherogenic plus 2% cranberry powder diet group (HFC + C2), and atherogenic plus 5% cranberry powder diet group (HFC + C5), and respective diet and water were fed daily for 6 weeks. After the experimental period, the serum lipid profile, such as total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride, ferric reducing ability of plasma (FRAP), plasma phenolics content, superoxide dismutase (SOD) activity, serum protein carbonyl and thiobarbituric acid reactive substances (TBARS) levels were examined. Total phenolic compound and total flavonoid levels in freeze-dried cranberry powder were 9.94 mg/g and 8.12 mg/g, respectively. Serum total cholesterol and LDL-cholesterol levels were not significantly different for cranberry powder treatment, but serum HDL-cholesterol level was significantly increased in HFC + C5 group compared with HFC group. Plasma FRAP value tended to be increased by cranberry powder treatment though there was no significant difference. Plasma total phenol concentrations and SOD activities were not significantly different among all groups. Serum protein carbonyl and TBARS levels were significantly decreased in HFC + C5 group compared with HFC group. Overall results suggested that freeze-dried cranberry powder might have the serum lipid improving effect, as well as antioxidative effect demonstrated by its protective effect against protein and lipid oxidation.