Effect of different concentrations of Gegen Qinlian decoction on expression of P-glycoprotein and multi-drug resistance protein transporter in Caco-2 cells / 中国中药杂志

To investigate the effects of Gegen Qinlian decoction on the expression of P-glycoprotein (P-gp) and multi-drug resistance protein (MRP) in epithelial cells of human colon adenocarcinoma Caco-2 cells．The effects of different concentrations of Gegen Qinlian decoction on the expression levels of p-gp and MRP1-6 mRNA in Caco-2 cells were detected by real time quantitative reverse transcriptase PCR (qRT-PCR).12 h after drug treatment (5.00 g·L⁻¹), the expression levels of MDR1 and MRP1-6 were significantly down-regulated at concentration of 5.00 g·L⁻¹; the mRNA expression levels of MDR1，MRP1，MRP2，MRP4，MRP5 and MRP6 were significantly down-regulated at concentration of 2.50 g·L⁻¹; only the expression levels of MRP2 and MRP5 were significantly affected at concentration of 1.00 g·L⁻¹. The results showed that the expression levels of MDR1 and MRP1-6 mRNA in Caco-2 cells could be down-regulated in a dose-dependent manner. Gegen Qinlian decoction may reduce drug efflux by down-regulating the mRNA expression of cell transporters in Caco-2 cell, and increase the time of drug action, thereby enhancing the bioavailability of chemotherapeutic drugs.

Research on intestinal permeability of glycyrrhetinic acid in multicomponent environment / 中草药

Objective: To investigate the characteristics of intestinal absorption of glycyrrhetinic acid in rats in the multicomponent environment. Methods: The effect of multicomponent environment on intestinal absorption of glycyrrhetinic acid was investigated in rat model of in situ single-pass intestinal perfusion, HPLC was used to determine the concentration of glycyrrhetinic acid in intestinal perfusion fluid samples, the effective permeability coefficient (Peff), absorption rate constant (Ka), and absorption fraction (Fa) of glycyrrhetinic acid in rats ileum were calculated, the effects of glycyrrhetinic acid with different mass concentration and P-glycoprotein (P-gp) inhibitor verapamil, as well as the compatibility of different components on intestinal absorption of glycyrrhetinic acid were examined,. Results: The Peff, Ka, and Fa values of glycyrrhetinic acid perfusion liquid (10 and 20 µg/mL) in the ileum segment had no significant difference. Added with 100 µmol/L verapamil, Peff, and Fa values of 10 µg/mL glycyrrhetinic acid increased, which illustrated that the glycyrrhetinic acid might be the substrate of P-gp; In two components compatibility, the effect of baicalin on absorption of glycyrrhetinic acid was the most obvious, Peff value of glycyrrhetinic acid was from (4.05 ± 0.78) × 10-5 cm/s to (2.18 ± 0.63) × 10-5 cm/s, and the penetration of glycyrrhetinic acid was reduced. The puerarin consociation baicalin and berberine had no obvious effect on permeability of glycyrrhetinic acid. In the three components compatibility condition, the experimental results showed that after glycyrrhetinic acid combined with puerarin and berberine, the permeability coefficient did not change, while the permeability coefficient changed, but not obviously, glycyrrhetinic acid combined with baicalin and berberine had lower permeability, Peff values were from (4.05 ± 0.78) × 10-5 cm/s down to (1.35 ± 0.69) × 10-5 cm/s, and the effects of baicalin on glycyrrhetinic acid was evident. Conclusion: Glycyrrhetinic acid can be absorbed in the ileum of rats, and has no obvious influence on Peff and Ka values within a certain range of quality concentration. The absorption mechanism is determined to be passive diffusion, glycyrrhetinic acid is substrate of P-gp, and saturation phenomenon exists transporters; Baicalin has significant effects on glycyrrhetinic acid absorption, which may be related to the induction by P-pg expression, increasing the glycyrrhetinic acid from cell to the extracellular discharge, reducing the penetration of glycyrrhetinic acid, and influencing the absorption.

Biopharmaceutics classification system of Chinese materia medica of berberine in Gegen Qinlian decoction / 中国中药杂志

One of the top-level researches of biopharmaceutics classification system of Chinese materia medica (CMMBCS) is the study on single component in compound Chinese medicine. The medicines shall be classified according to its solubility and intestinal permeability, as well as the ascending degree in multicomponent environment. Based on above, we chose berberine as the main object to explore the change rules of its solubility and intestinal permeability in Gegen Qinlian decoction. Shaking flask-HPLC was used to detect the solubility changes of berberine in compounds. The qualitative investigation of berberine in intestinal absorption was measured by everted gut sac, and the quantitative research of berberine in intestinal absorption was measured by single-pass intestinal perfusion experiment, while the qualitative and quantitative research of berberine absorption into blood was measured by in intestinal perfusion with venous sampling experiment.

Validation of in situ single pass perfusion model based on P-gp / 中国中药杂志

To validate in situ rats intestinal single pass perfusion model based on P-glycoprotein (P-gp). Firstly, phenol red perfusion was carried out to verify the close connection structure of intestinal epithelial cells, and the integrity of the intestinal epithelium, with a gravimetric method for correcting water flux. The level of phenol red was determined by high performance liquid chromatography (HPLC) both before and after perfusion. Secondly, the positive drug digoxin specified by FDA was used to validate the model. After different mass concentrations of verapamil were given in the rats, the absorption parameters of digoxin in ileum of rats were observed and compared. The results showed that the phenol red was absorbed in rats ileum segment, with an effective permeability coefficient of (1.09±0.62)×10 ⁻⁶ cm•s ⁻¹. The experiment results indicated that the close connection structure of intestinal epithelial cells was normal, and the integrity of the intestinal epithelium was maintained well. In digoxin perfusion experiment, in case no verapamil was given, digoxin showed certain degree of absorption in rat ileum, with an effective permeability coefficient (Peff) of (1.07±0.59)×10 ⁻⁵ cm•s ⁻¹; after mass concentrations of 0.01,0.1 mmol•L ⁻¹ verapamil were given, the absorption of digoxin was on the rise in rat ileum, with an effective permeability coefficient Peff of (1.58±0.69)×10 ⁻⁵, (3.28±0.95)×10 ⁻⁵ cm•s ⁻¹ respectively (P<0.05). Digoxin perfusion experiment verified that P-gp expression in small intestine epithelium was intact and can be used in the research of P-gp efflux transporter.

Study on property of biopharmaceutics classification system of berberine in Huanglian decoction / 中国中药杂志

The study of single component in the multicomponent environment is one of the basic researches for biopharmaceutics classification system of Chinese materia medica (CMMBCS). That is to say, the classification research shall be based on the respective lift of solubility and permeability in the multicomponent environment, besides solubility and intestinal permeability of the single component. We chose berberine as the main research object to investigate the changes of its solubility and intestinal permeability in Huanglian decoction. Shake-flask and HPLC were used to detect the solubility of berberine in different pH buffer solutions and different concentrations of Huanglian decoction. In situ single-pass intestinal perfusion (SPIP) and intestinal perfusion with venous sampling (IPVS) were carried out to study berberine's intestinal absorption and absorption into blood, respectively.

Overall intestinal permeability of multiple components in lotus leaves / 中国中药杂志

In the study of biopharmaceutics classification system of Chinese materia medica (CMMBCS), the interactions of multiple components in the absorption should be taken into consideration in simultaneous multi-component determination. To investigate the absorption of multiple components, the in vitro everted gut sac model was used in this study, wtih lotus leaves as the research object. Aquantitative analysis was also carried out for the known components in this study. Totally 19 components in lotus extracts were absorbed by the intestinal tract, the Papp levels of the known components were nuciferine (1×10⁻⁵-1×10⁻⁶ cm•s⁻¹), rutin (1×10⁻⁶-1×10⁻⁷ cm•s⁻¹), hyperoside (1×10⁻⁶ cm•s⁻¹), isoquercitrin (1×10⁻⁶-1×10⁻⁷ cm•s⁻¹) and astragalin (1×10⁻⁶-1×10⁻⁷ cm•s⁻¹), respectively. These components showed a low permeability under a multi-component environment. This study was carried out to lay a foundation for further relevant target studies for different categories of components.