Absorption and Metabolism of Luteolin and Its Glycosides from the Extract ofChrysanthemum morifoliumFlowers in Rats and Caco-2 Cells

To elucidate the bioavailability of luteolin and its glycosides in Chrysanthemum morifolium flowers, the absorption and metabolism of luteolin from them was investigated in rats and Caco-2 cells using HPLC and LC-MS. After oral administration of C. morifolium extract (1.7 g/kg body weight (bw), equivalent to 22.8 and 58.3 μmol/kg bw of luteolin and luteolin-7-O-glucoside, respectively) to rats, luteolin and its glycosides were quickly absorbed and luteolin, luteolin monoglucoside, and luteolin monoglucuronide were detected in the plasma. Their levels were highest at 1 h after administration (0.76 ± 0.27 μM). These compounds were also detected in media on the basolateral side from Caco-2 cells treated with the C. morifolium extract. These results suggest that luteolin and luteolin monoglucoside are rapidly absorbed after administration of C. morifolium flower extract and that luteolin, luteolin monoglucoside, and luteolin monoglucuronide may circulate in humans.