Metabolic Profiling of Dietary Polyphenols and Methylxanthines in Normal and Malignant Mammary Tissues from Breast Cancer Patients

SCOPE: Dietary polyphenols may protect against breast cancer. However, it is unknown whether polyphenols reach human malignant breast tumors in molecular forms and(or) at concentrations likely to act against cancer. METHODS AND RESULTS: ) are urolithin-A-3-O-glucuronide (26.2; 3.2-66.5), 2,5-dihydroxybenzoic acid (40.2; 27.7-52.2), resveratrol-3-O-sulfate (86.4; 7.8-224.4), dihydroresveratrol-3-O-glucuronide (109.9; 10.3-229.4), and theobromine (715.0; 153.9-3,216). Metabolites, as detected in breast tissues, do not exert antiproliferative or estrogenic/antiestrogenic activities in MCF-7 breast cancer cells. CONCLUSION: This is the first study that describes the metabolic profiling of dietary phenolics and methylxanthines in MT and NT comprehensively. Although phase-II conjugation might hamper a direct anticancer activity, long-term tumor-senescent chemoprevention cannot be discarded.