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

ABSTRACT

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.