Absorption, distribution, metabolism, and excretion of decursin and decursinol angelate from Angelica gigas Nakai

The pharmacokinetics of decursin and decursinol angelate (D/DA) was investigated in male SD rats following oral and intravenous administration. D/DA and metabolites obtained from in vitro samples were evaluated by LC/MS. The level of D/DA and metabolized decursinol in the blood following oral and intravenous administration declined according to first-order kinetics, with T1/2 values of 56.67, 58.01 and 57.22 h, respectively, being observed after administration of a dose of 2 mg/kg body weight. The large intestine was the major site of disposition following oral administration. These data indicate that D/DA is rapidly absorbed from the gastrointestinal tract. In in vitro experiment utilizing liver microsomal protein, the major metabolic reaction of D/DA occurred to change decursinol. The cumulative biliary, urinary, and fecal excretion of D/DA in bile duct-cannulated rats was 36.10+/-2.9, 25.35+/-3.8, and 34.20+/-3.2%, respectively, at 72 h after administration. These results indicate that the absorption of D/DA is almost complete, and that its metabolites are primarily excreted into feces through the bile. These results indicate that D/DA is subject to enterohepatic circulation.