Flavonoid Fractions from Cranberry Extract Inhibit Growth of Human Tumor Cell Lines

摘要

In spite of improvements in cancer chemotherapy, approximately 50% of cancers are not cured and improvement is needed. Given the association of diets high in fruits and vegetables with lower cancer risk, these foodstuffs have been investigated as sources of compounds to both prevent cancer and treat established tumors. Flavonoids, found in high amounts in cranberries, contribute to improved human health. A flavonoid-rich extract of cranberries (Fr6) and isolated polymers of the flavan-3-ol class of cranberry flavonoids (proanthocyanidins, PACs) were investigated for anticancer activity. Both Fr6 and PACs inhibited proliferation of various human cancer cell lines when grown in culture (in vitro). When Fr6 or PACs were administered by injection to mice bearing explants of human tumor cell lines, growth of the tumors was delayed. When treating the prostate tumor cell line DU145 explant, 50% of tumors completely regressed. Both Fr6 and PACs were able to block cell cycle progression and induce cell death. Subfractionation of Fr6 by high performance liquid chromatography yielded fractions containing 3 detectable peaks that exhibited most of the in vitro anticancer activity. Work continues on identifying these compounds, which appear to differ chemically from those identified in other laboratories. It is proposed that several components of cranberry will be identified for use in humans as a cancer preventive dietary supplement and, potentially, as a treatment for established tumors.