Absorption of polymethoxyflavones and their derivatives

Abstract

Polymethoxyflavones (PMFs) are a group of flavonoids found exclusively in citrus genus that have been identified with many potent biological activities, including anti-inflammation, anti-cancer, anti-atherosclerosis, and antioxidant effects. However, the bioavailability of PMFs is seldom studied. Evaluating by aqueous solubility and permeability, absorption is the first indicator of bioavailability. In this research, we systemically investigated permeability and solubility of six PMFs and their derivatives, namely, sinensetin (SIN), 5-demethylsinensetin (5-OHSIN), 5-acetylsinensetin (5-AcSIN), 3,5,6,7,8,3′,4′-heptamethoxyflavone (HeptaMF), 5-hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone (5-OHHeptaMF), and 5-acetyl-3,6,7,8,3′,4′-hexamethoxyflavone (5-AcHeptaMF). From octanol/water solubility test, we found that PMFs and their derivatives had very low aqueous solubility. Permeability experiment via Caco-2 cell monolayer transport model indicated high permeability of all the tested compounds. Furthermore, PMFs had the greatest permeability, followed by 5-acetyl PMFs and 5-hydroxylated PMFs. Considering permeability and solubility together, PMFs and their derivatives are expected to have good absorption. This study provides indicative information on the bioavailability of PMFs and their derivatives, which offers clues on the application of PMFs in functional food or nutraceutical products.