Elucidation of the Transport Mechanism of Puerarin and Gastrodin and Their Interaction on the Absorption in a Caco-2 Cell Monolayer Model

Puerarin (PUR) and gastrodin (GAS) are often used in combined way for treating diseases caused by microcirculation disorders. The current study aimed to investigate the absorption and transportation mechanism of PUR and GAS and their interaction via Caco-2 monolayer cell model. In this work, the concentration in Caco-2 cell of PUR and GAS was determined by HPLC method. The bidirectional transport of PUR and GAS and the inhibition of drug efflux including verapamil and cyclosporine on the transport of these two components were studied. The mutual influence between PUR and GAS, especially the effect of the latter on the former of the bidirectional transport were also investigated. The transport of 50 μg·mL⁻¹ PUR in Caco-2 cells has no obvious directionality. While the transport of 100 and 200 μg·mL⁻¹ PUR presents a strong directionality, and this directionality can be inhibited by verapamil and cyclosporine. When PUR and GAS were used in combination, GAS could increase the absorption of PUR while PUR had no obvious influence on GAS. Therefore, the compatibility of PUR and GAS is reasonable, and GAS can promote the transmembrane transport of PUR, the effect of which is similar to that of verapamil.