Chemistry and health effects of polymethoxyflavones and hydroxylated polymethoxyflavones

Polymethoxyflavones (PMFs) and hydroxylated polymethoxyflavones exist exclusively in citrus genus, especially in the citrus peels which have been used as herbal medicine for several diseases for thousands of years. In this review, the natural occurrence, isolation and separation of PMFs; synthetic scheme of hydroxylated PMF preparation, especially the reaction mechanism of preparation of 5-hydroxylated PMFs; biotransformation and metabolic fate of PMFs; the preliminary study on PMF bioavailability and the close relationship among solubility, permeability, absorption and oral bioavailability are summarized. The published bioactivity data on anti-inflammatory, anti-cancer and anti-atherogenic properties of PMFs have also been detailed along with a report of new findings of hydroxylated PMFs and their potent biological activities.