Cranberry and its related fruits and their beverage products have received considerable attention for their health beneficial effects to human beings. These health benefits include prevention and treatment of urinary tract infections (UTIs), stomach ulcers, gum diseases, dental infections, blocking biofilm formation associated with bacterial infections, providing protection against aging, stroke, cardiovascular diseases and more recently anticancer activity. In spite of research in the past few decades, little is known about the molecular mechanism of action of these health beneficial effects. We have initiated research exploring the possible mechanisms. Based on the chemical structures and bioactivities of certain cranberry constituents, as well as the current understanding of iron homeostasis and its relation to medicine, a novel molecular mechanism of action for certain health benefits of cranberry has been hypothesized in this proposal. This mechanism may give reasonable biochemical explanations to many of the health benefits demonstrated for cranberry and its related fruits so far. The general goal of the work proposed here is to test this hypothesis. Multi-disciplinary approach including using knowledge and techniques from chemistry, electrochemistry, biochemistry and molecular biology, microbiology, spectroscopic methods and X-ray crystallography have been designed to test the proposed mechanisms. Experiments described herein are designed to elucidate the iron-binding properties of certain cranberry constituents, including structures and affinities, and the effects of these properties on the antibacterial, antioxidant and antitumor properties of cranberry and its related products. This research has profound impact to applying cranberry and its related fruits and products in human health, nutrition and medicine.