[Absorption of extractive Radix Paeoniae Alba in rat everted gut sacs and its interaction with P-glycoprotein].

OBJECTIVE

To research the intestinal absorption characteristics of paeoniflorin in extractive Radix Paeoniae Alba in the different intestinal segment, and the interaction with P-glycoprotein.

METHOD

Paeoniflorin, a representative component in extractive Radix Paeoniae Alba, on the intestinal absorption was studied in vitro using everted gut sacs model and detected by HPLC method. The absorption characteristics was evaluated by the absorption parameter.

RESULT

The absorption of paeoniflorin was linearity at different intestine segment and dose, and the square of regrees correlation coefficient exceed 0.9 (R2 > 0.9), which consistent with zero order rate process. The Kalpha of paeoniflorin showed a dose-dependent increase along with the raised dose of extractive Radix Paeoniae Alba, indicated it was a mechanism of passive absorption. The absorption rate was jejunum > ileum > colon. Verapamil (100 micromol x L(-1)), a inhibitor of the P-glycoprotein, can remarkable increase the absorption of the paeoniflorin in ileum (P < 0.05). After administer the extractive Radix Paeoniae Alba for 5 days, the extraction of Rho123 is significantly increase in ileum (P < 0.01).

CONCLUSION

The intestinal absorption of paeoniflorin is zero order rate process and passive absorption. Paeoniflorin is a substrate of P-glycoprotein, and extractive Radix Paeoniae Alba could induce the expression of the P-glycoprotein.