Pharmacokinetics of ginsenosides following repeated oral administration of red ginseng extract significantly differ between species of experimental animals.

We aimed to investigate ginsenoside pharmacokinetics in mice and rats following the repeated oral administration of red ginseng extract (RGE) (2 g/kg/day for 7 days). In mouse plasma, seven protopanaxadiol (PPD)-type ginsenosides (20(S)-ginsenoside Rb1, Rb2, Rc, Rd, Rg3, 20(S)-compound K, and 20(S)-PPD) and one protopanaxatriol (PPT)-type 20(S)-ginsenoside Re were detected, whereas 20(S)-ginsenoside Rb1, Rb2, Rc, Rd, 20(S)-PPD, and 20(S)-PPT were detected in rat plasma. The tetra- or tri-glycosylated PPD-type ginsenosides Rb1, Rb2, Rc, and Rd, high content ginsenosides in RGE, showed high plasma exposure, a short absorption time (Tmax), and a long elimination time (T1/2) among the ginsenosides detected in both species. Among the deglycosylated metabolites existing in the feces, 20(S)-compound K and 20(S)-PPD in mice and 20(S)-PPD and 20(S)-PPT in rats were found in the plasma samples. In addition to the differences in the ginsenosides detected in mice and rats, the Tmax and T1/2 of 20(S)-PPD and 20(S)-PPT in rats were greater than those in mice, suggesting the species-dependent difference in the gut metabolism and absorption of ginsenosides in the pathway from 20(S)-ginsenoside Rd to 20(S)-PPD and from 20(S)-ginsenoside Re to 20(S)-PPT. In conclusion, the choice of animal model should be the subject of careful consideration when exploring the pharmacology of RGE with specific focus on the plasma profile of an individual ginsenoside.