Chemopreventive effects of orange peel extract (OPE) II. OPE inhibits atypical hyperplastic lesions in rodent mammary gland

Cancer chemoprevention via the ingestion of natural substances is a current topic of considerable interest. Flavonoids are a family of biologically active phytochemicals having a variety of biological effects. Orange peel extract (OPE) is an abundant source of polymethoxyflavones (PMFs) with potential chemopreventive properties. The OPE used here was a mixture containing tangeretin (19.0%), heptamethoxyflavone (15.24%), tetramethoxyflavone (13.6%), nobiletin (12.49%), hexamethoxyflavone (11.06%), and sinensitin (9.16%). C57Bl/6 mice were fed a new “Western-style” diet (NWD), which had previously induced atypical hyperplasias in mammary gland, and NWD supplemented with a standardized OPE containing 30% PMFs. Mice were fed one of four diets: (1) AIN-76A diet (control); (2) NWD; (3) 0.25% OPE in NWD; or (4) 0.5 % OPE in NWD. After 3 months of feeding, atypical hyperplasias developed in mammary glands of mice fed NWD, but not in controls. After feeding OPE in NWD, atypical hyperplasias per mouse decreased in ...