[Intestinal Absorption Characteristics and Mechanism of Polygala tenuifolia Hydrolysate in Rats]

To evaluate the absorption feature and mechanism of tenuifolin(TF) and polygalaxanthone III (PT) in different intestinal parts of rats and the impact of MRP2 and P-glycoprotein (P-gp) on it.

In situ unidirectional perfusion was used to detect the concentration of TF and PT through HPLC-DAD with gravimetric method. Furthermore, impact of different parts, cosolvents and inhibitors to TF and PT was also explored with data of Ka and Papp.

Tween as cosolvent, Ka and Papp of TF was significantly higher in colon than in other intestinal parts(P <0. 05 or P <0. 01). Whereas, Ka of PT was in sequence of colon, duodenum, jejunum, ileum,but with no significant difference among them(P >0. 05). SDS as cosolvent, Papp of TF was higher in colon than in duodenum(P <0. 05). K. of TF was significantly higher compared with control when added with VH, an inhibitor of P-gp(P <0. 05). In addition, Papp of PT in different concentration of VH increased(P <0. 05, P <0. 01). Papp of TF significantly increased with IT at the concentration of 0. 02 and 0. 04 mmol/L, an inhibitor of MRP2(P <0. 05, P <0. 01). Meanwhile, Ka of PT,with IT at the concentration of 0. 04 and 0. 08 mmol/L, was significantly higher(P <0. 05, P <0. 01).

TF is mainly absorbed in colon, whereas PT is in duodenum. P-gp but not MRP2 influences the intestinal absorption of TF, indicating TF as substrate of P-gp. However, both of P-gp and MRP2 impact the absorption of PT, illustrating PT as substrate of P-gp and MRP2. It also indicates that inhibitors of P-gp and/or MRP2 in combined application may improve the absorption of PT and TF.