Pharmacokinetic Comparison of Scutellarin and Paeoniflorin in Sham-Operated and Middle Cerebral Artery Occlusion Ischemia and Reperfusion Injury Rats after Intravenous Administration of Xin-Shao Formula.

Xin-Shao formula is a folk remedy widely used in China to prevent and cure stroke. Cerebral ischemic reperfusion (I/R) injury often takes place during the treatment of stroke. Information about the pharmacokinetic behavior of the remedy under cerebral I/R injury conditions is lacking. The present study aimed to compare the pharmacokinetic properties of scutellarin and paeoniflorin, two major bioactive components of Xin-Shao formula, under physiological state in cerebral I/R injury rats. Neurobehavioral dysfunction was evaluated and cerebral infarcted volume was measured in middle cerebral artery occlusion I/R injury (MCAO) rats. Plasma samples were collected at various time points after a single dose (intravenous, i.v.) of Xin-Shao formula. The levels of plasma scutellarin and paeoniflorin at the designed time points were determined by a UPLC-MS/MS method, and drug concentration versus time plots were constructed to estimate pharmacokinetic parameters. Increase in terminal elimination half-life (t1/2z) and mean residence time (MRT(0-t)) of scutellarin as well as elevation in area under the plasma drug concentration-time curve from 0 h to the terminal time point (AUC(0-t)) and maximum plasma drug concentration (Cmax) of paeoniflorin, along with decreased clearance of paeoniflorin and scutellarin as well as reduced apparent volume of distribution (Vz) of paeoniflorin, were observed in MCAO rats, compared with those in sham-operated animals. The elimination of scutellarin and paeoniflorin were reduced in cerebral I/R injury reduced rats.

[Absorption characteristics of 5 components of Xinshao extract in Caco-2 cells].

To study the absorption characteristics of Xinshao extracts in Caco-2 cells. In this paper, human colon adenocarcinoma cell line Caco-2 cell model was established, and UPLC-MS method was applied to determinate the contents of five components of Xinshao extracts(albiflorin, gallic acid, caffeic acid, scutellarin and apigenin-7-O-glucronide) in cell lysates. This model was also used to study the effect of different drug concentrations, pH, time and temperature on the absorption of five components, investigate the transport of the five components of Xinshao extracts under the conditions with or without P-glycoprotein inhibitors, and predict the absorption mechanism of these five components in Caco-2 cells. The experimental results showed that the absorption of five components of Xinshao extracts in Caco-2 cells was time-dependent at 37 ℃, and concentration-dependent in the range of 0.5-12.5 g•L⁻¹, with a passive diffusion mechanism. At the pH of 4-7.4, the absorption of caffeic acid, scutellarin and apigenin-7-O-glucronide was significantly declined with the increase of pH(P<0.05). At the temperature of 4 to 37 ℃, the absorption of caffeic acid was declined with the increase of temperature, while the absorption of other four components was increased with the increase of temperature. Compared with the control group, caffeic acid and scutellarin cell absorption was significantly higher(P<0.05) after treatment with P-glycoprotein inhibitors(verapamil and cyclosporine A). The results indicated that, the absorption mechanism of five components in Xinshao extracts may be of passive diffusion, and the caffeic acid and scutellarin may be the substrates of P-glycoprotein.