The transport of gastrodin in Caco-2 cells and uptake in Bcap37 and Bcap37/MDR1 cells

Gastrodin (GAS) is the major bioactive component of the extracts from the rhizome of Gastrodia elata Blume.  The aim of this study is to investigate the transport of GAS in Caco-2 cells and the interaction of P-glycoprotein and GAS.  The apparent permeability coefficients (P_app) of GAS were measured as a function of directions and concentrations.  It was demonstrated that the efflux ratio was < 2.0 over the range of 50−500 μmol·L⁻¹ of GAS from bi-directional transport studies.  The transport rate of GAS was dependent on the  concentrations.  P_app of GAS was not affected by transport directions, GAS concentration or the classical  inhibitors of P-glycoprotein (verapamil and GF 120918).  The cellular accumulation of GAS in Bcap37/MDR1 cells transected with hMDR1 gene, was similar to that in Bcap37 cells.  The accumulation in both cell lines was concentration dependent.  GAS did not affect the accumulation of Rhodamine 123 in Bcap37/MDR1 cells over the range of 50−500 μmol·L⁻¹.  It indicated that the transport of GAS in Caco-2 cell monolayers mainly is by passive paracellular transport pathway.  P-glycoprotein did not participate in the absorption of GAS in the  intestine or the transport across the blood-brain barrier.