Plant Proanthocyanidin Extract Effective at Inhibiting Adherence of Bacteria with P-type Fimbriae to Surfaces

Left: Bacterial Anti-Adhesion Activity of A-type Proanthocyanidins. Right: Cranberry (Vaccinium macrocarpon)

Invention Summary:

Rutgers scientists have isolated and identified unique A-type plant proanthocyanidin extracts that are useful for prevention of bacterial adhesion caused by P-fimbriated Escherichia coli or other microorganisms containing structurally-related fimbriae or molecules involved in microbial adherence. Adhesion is the initial step in development of urinary tract and other bacterial infections. While such extracts can be obtained from a variety of proanthocyanidin-containing plants, they are preferably obtained from cranberry plants (Vaccinium macrocarpon). Cranberry is very high in the unusual A-type proanthocyanidins, which are linked to the prevention of bacterial adhesion, as opposed to the B-type proanthocyanidins found in other plants, which do not exhibit this activity.

The straightforward extraction method involves homogenizing plant material (leaves, fruit, etc.) in a mixture of water, acetone, methanol, and ascorbic acid and purifying the extract obtained. Positive results have been obtained confirming the bioactivity of the extracts using various assays, including inhibition of bacterial adherence. The extracts are highly potent and active at a concentration of 10 ug/mL, as opposed to the majority of whole cranberry products, which are active at about 7 mg/mL.

The extracts of this invention can be used in a variety of applications, in particular prevention and treatment of urinary tract infections caused by P-fimbriated E. coli, and in various forms (e.g., as a food/beverage ingredient or supplement in pills, capsules, tablets, concentrate, powders, juices). 

Market Applications:

  • Urinary Tract Infection
  • Supplements
  • Nutraceuticals
  • Food
  • Beverages
  • Pet/Animal Feed


  • First identification of the bioactive compounds that inhibit P-type E. coli from adhering to surfaces such as uroepithelial cells.
  • Compared to other known extraction methods, the developed method results in improved yields of sugar-free purified A-type proanthocyanidins with less oxidative damage and/or structural degradation.
  • The extracts could help reduce antibiotic resistance issues because they do not kill the bacteria, like other common antibiotics. They inhibit a step in the infection process. The extract would be a high potency, safe alternative for low-dose antibiotic use in prevention of urinary tract infections.

Intellectual Property & Development Status:

Issued United States Patents 6,608,102, 6,720,353, and others.

Rutgers ID: 1998-0017
Food, Nutrition and Nutraceuticals
Deborah Perez
Senior Licensing Manager
Nicholi Vorsa
Amy Howell