Abstract
Decursin is considered the major bioactive compound of Angelica gigas roots, a popular Oriental herb and dietary supplement. In this study, the pharmacokinetics
of decursin and its active metabolite, decursinol, were evaluated after the administration
of decursin in rats. The plasma concentration of decursin decreased rapidly, with
an initial half-life of 0.05 h. It was not detectable at 1 h after intravenous administration
at an area under the plasma concentration-time curve of 1.20 µg · mL−1·h, whereas the concentration of decursinol increased rapidly reaching a maximum concentration
of 2.48 µg · mL−1 at the time to maximum plasma concentration of 0.25 h and an area under the plasma
concentration-time curve of 5.23 µg · mL−1·h. Interestingly, after oral administration of decursin, only decursinol was present
in plasma, suggesting an extensive hepatic first-pass metabolism of decursin. The
extremely low bioavailability of decursin after its administration via the hepatic
portal vein (the fraction of dose escaping first-pass elimination in the liver, FH = 0.11) is indicative of extensive hepatic first-pass metabolism of decursin, which
was confirmed by a tissue distribution study. These findings suggest that decursin
is not directly associated with the bioactivity of A. gigas and that it may work as a type of natural prodrug of decursinol.
Key words
decursin - decursinol - first-pass metabolism - absorption barrier -
Angelica gigas Nakai - Apiaceae
