头花蓼提取物的大鼠在体肠吸收研究

利用大鼠在体循环灌流模型,采用UPLC-ESI-MS/MS测定灌流液中头花蓼提取物主要活性指标成分没食子酸、原儿茶酸、杨梅苷、金丝桃苷和槲皮苷的含量,并计算出吸收速率常数和累积吸收百分率。分别考察不同药物浓度、不同肠段、胆汁及P-糖蛋白抑制剂对头花蓼提取物中没食子酸等成分在大鼠体内的吸收机制的影响。实验结果表明,头花蓼提取物中没食子酸、原儿茶酸、杨梅苷、槲皮苷在高浓度下存在饱和现象(P<0.05);胆汁对原儿茶酸的吸收具有显著的抑制作用(P<0.05),对杨梅苷和金丝桃苷的吸收具有促进作用(P<0.05);P-糖蛋白抑制剂维拉帕米能显著增加原儿茶酸的吸收(P<0.05);各成分的吸收总体趋势为小肠优于结肠。表明头花蓼提取物在大鼠肠道的吸收符合一级动力学特征。几种成分在整个肠段都有吸收,主要吸收部位在小肠,原儿茶酸可能是转运蛋白P-gp的底物。

Intestinal absorption kinetics of Polygonum capitatum extract in rats

A UPLC-ESI-MS/MS method was used to determinate the main active fractions gallic acid, protocatechuic acid, myricetrin, hyperoside and quercitrin in Polygonum capitatum extracts by in situ intestinal perfusion models; the absorption rate constants and cumulative penetration rate of absorption were calculated. The effect of different drug concentrations, different intestine segments, bile and P-gp inhibitors on the absorption mechanism of Gallic acid and other compositions in P. capitatum extracts. The experimental results showed that gallic acid, protocatechuic acid, myricetrin and quercitrin were observed saturated at high concentration (P<0.05). Bile had significant inhibition effect on protocatechuic acid absorption and had promotion effect on myricetrin and hyperoside absorption (P<0.05). P-gp inhibitor verapamil could significantly enhance the absorption of Protocatechuic acid (P<0.05). The overall trend for absorption of various compositions was that small intestine>colon. This indicated that the absorption mechanism of P. capitatum extracts in rat intestine was in line with fist-order kinetics characteristics. The compositions could be absorbed in all of the different intestinal segments, and the absorption was mainly concentrated in small intestine. The protocatechuic acid may be the substrate of P-gp.