Impact of saikosaponin on absorption and transport of paeoniflorin in Caco-2 cell model

Abstract

To study the impact of saikosaponin on absorption and transport of paeoniflorin in Caco-2 cell model. The concentration of paeoniflorin in cell culture medium was measured by UPLC and the apparent permeability coefficients (P(app)) was calculated to study differences in bi-direction transport of paeoniflorin solutions of different concentrations and its compatibility with saikosaponin a, and saikosaponin d in Caco-2 cell model. Meanwhile, the electric resistance of Caco-2 cell was determined before and after the experiment. The amount of paeoniflorin increased linearly with the transport of Caco-2 cell monolayer in 4 h, with a lower absorptive permeability, which was (0.98 +/- 0.10) x 10(-6), (0.92 +/- 0.09) x 10(-6), (0.89 +/- 0.04) x 10(-6) cm x s(-1) at the concentration of 20, 50, 100 micromol x L(-1), respectively. After compatibility with saikosaponin a and saikosaponin d, the absorptive permeability of paeoniflorin increased by 2.37 times and 2.54 times, respectively, while the electric resistance of Caco-2 cell was decreased significantly after the experiment. Saikosaponin a, d can enhance the absorption of paeoniflorin in Caco-2 cell monolayer, which may be related to saikosaponin's ability to open up intercellular tight junctions among Caco-2 cells.