Objective: To study absorption and transport characteristics of effective components from Isatidis Radix in Caco-2 cell. Method: Safety of drug candidates from Isatidis Radix was evaluated by establishing absorption and transport model of Caco-2 cells

which were qualified beforehand with three indexes including trans-epithelial electrical resistance(TEER)

alkaline phosphatase activity and permeability of sodium fluorescein.Several influential factors for absorption and transport process of effective components from Isatidis Radix had been investigated

such as concentration

time

temperature

pH value and inhibitors.HPLC was set up for determination of these compounds

their apparent permeability coefficients(Papp) and efflux rates were calculated. Result: Arginine and adenosine from Isatidis Radix could be absorbed well by absorptive cells of small intestine with Papp of 1.01×10-6-1.35×10-6 cm·s-1 and 0.40×10-6-0.71×10-6 cm·s-1

respectively.Two kinds of ingredients show good permeability in Caco-2 cell

following by absorbed degree of arginine with rate of>50%

better than that of adenosine.Efflux rates(ER) of arginine and adenosine from Isatidis Radix extract were between 1.0-2.0

indicating P-glycoprotein(P-gp) efflux effect existed in absorption and transport process of these two compounds.And other compounds from Isatidis Radix could enhance efflux effect of P-gp on absorption of arginine and adenosine. Conclusion: Arginine and adenosine from Isatidis Radix can be absorbed well by absorptive cells of small intestine

and directional differences of absorption and transport process in Caco-2 cells are found out with P-gp efflux effect.